Theses and Dissertations Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/106

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Efficacy of commonly used anthelmintics in selected sheep farms in Arusha
(Sokoine University of Agriculture, 2006) Chang’a, Jelly Senyagwa
Morphological study of the ileal Peyer’s patches of mammals
(Sokoine University of Agriculture, 2001) Antallo,Hando Hussein
Ileal Peyer’s patches of some mammals such as sheep and goats have similar morphological characteristics to the avian bursa of Fabricius. The objective of this study was therefore to obtain more data on the morphological properties and life history of ileal Peyer’s patches in a wider range of mammalian species. Thus, gross and histologic methods were used to evaluate the morphological changes in the ileal Peyer’s patches during fetal, youth and adult periods in wildebeests, reedbucks, cattle, donkeys, pigs, dogs, cats, wild rats, giant rats, baboons and vervet monkeys. In each age group three animals were used. Grossly, no Peyer’s patches were visible in duodenum, jejunum and ileum of fetuses except donkey fetuses, which had 29 ileal Peyer’s patches and 40 jejunal Peyer’s patches. However, microscopic evaluation of fetal ileal samples from fetuses of all mentioned species except rats at about mid gestation, showed accumulation of lymphoid cells in the sub-mucosa. During late fetal period, cattle and donkey fetuses had conical follicles while dogs had round follicles. In addition, bovine fetus ileal Peyer’s patch follicles showed distinct cortico-medulla differentiation. Young wildebeests, reedbucks, cattle, pigs, dogs and cats had long continuous band ofileal Peyer’s patch that covered the ileum and extended into the jejunum. Donkeys, baboons and vervet monkeys possessed 32, 1, 3 oval shaped individual ileal Peyer’s patches respectively, while rats had nopatches. Young wildebeests, reedbucks, cattle, cats, baboons and vervet monkeys possessed oval shaped jejunal Peyer’s patches numbering 32, 10, 26, 3, 12 and 18, respectively. Foals and puppies had round jejunal Peyer’s patches that numbered 48 and 8, respectively. No jejunal Peyer’s patches were seen in piglets and rats. Duodenal Peyer’s patches were only seen in puppies. Microscopically, ileal Peyer’s iii patch showed follicles that were sac-like, tightly packed, with clear cortico-medulla differentiation and small domes, corona and interfollicular areas. The adults of wildebeest, rcedbuck, cattle, pig, donkey, dog and cat had no grossly visible ileal Peyer’s patches. However, microscopically, sub-mucosa was filled with connective tissue. Nevertheless, wild rats had 2 and giant rats had 8 small round ileal Peyer’s patches that contained pear-shaped follicles, wider domes, conspicuous corona and large interfollicular areas. All animals under study possessed jejunal Peyer’s patches, which were bigger than those of respective youths and their numbers averaged 55 in wildebeest, 15 in rcedbuck, 37 in cattle, 8 in pig, 57 in donkey, 9 in dog, 6 in cat, 3 in wild rat and 17 in giant rat. Again, 3 duodenal Peyer’s patches were seen in dogs. Adults of non-human primates were not obtained. The study has therefore demonstrated presence of a continuous long ileal Peyer’s patches in young animals in orders; Artiodactyla and Carnivora while young animals of the order Perissodactyla had discrete round patches. At least, the study has also demonstrated a prenatal maturation of the ileal Peyer’s patches in the mammalian ordersArtiodactyla, Perissodactyla and Carnivora which is followed by full maturation at young age and lastly by involution at adulthood except in rats. This morphological pattern resembles that of avian bursa of Fabricius.
Prevalence of enterohaemorrhagic escherichia coli (ehec) o157:h7 in cattle meat (beef) in Tanzania.
(Sokoine University of Agriculture, 2002) Hayghaimo,Abdu Amman
A cross sectional study on the occurrence of EHEC O157:H7 serotype in cattle meat (beef) destined for human consumption was undertaken in two slaughterhouses of Tanzania between December 2000 and June 2001. Surface swabs were taken from 384 beef carcasses immediately after slaughter and were examined for EHEC O157:H7 by first growth enrichment in modified tryptone soya broth (mTSB), followed by immunomagnetic separation (IMS) and finally by culture of bead- 0157 media. Presumptive EHEC O157:H7 were isolated from 25 of 200 (12.5%) beef samples collected from Morogoro slaughterhouse and 21 of 184 (11.4%) beef samples collected from Ukonga- Mombasa slaughterhouse in Dar-es-Salaam. When the presumptive EHEC O157:H7 colonies were subjected to the latex agglutination and biochemical tests for confirmation, 22 (5.7%) isolates showed typical agglutination and biochemical patterns characteristic of EHEC O157:H7. This study suggests that beef in the two slaughterhouses may be contaminated with EHEC O157:H7. Given the hygienic conditions of most slaughterhouses in Tanzania, it can be concluded that beef from slaughterhouses if not properly cooked may present a risk of VTEC 0157 infections and associated disease to humans. This is the first report on the isolation of EHEC O157:H7 in cattle meat in Tanzania.
Immunohistochemical characterization and quantification of lymphocytes infiltrating lungs during east coast fever.
(Sokoine University of Agriculture, 2002) Kessy,Vallery Msafiri John
A study was conducted to investigate the hypothesis that the lungs in East Coast fever are infiltrated by different subsets of lymphocytes that may be responsible in the pathogenesis of pulmonary edema. Four steers 7-10 months old were experimentally infected by subcutaneous injection with 0.5 ml of live Theileria parva sporozoites (Muguga stabilate 3087). Two others remained as uninfected controls. All six animals were clinically monitored daily before and after infection by screening peripheral blood smears, lymph node smears, rectal temperatures, lymph node enlargement, coughing and dyspnea. Also blood samples were taken at intervals of 3-4 days and analysed for total RBC and WBC counts, Hb, PCV and exsanguinated to death under general anaesthesia at the onset of dyspnea, together with one of the controls for sampling of lung tissues. In addition, two lung tissue samples were collected from two ECF naturally infected cattie that were slaughtered during the advanced stage of the disease. The lung tissue samples from the experimentally and naturally infected animals were fixed in 4% neutralbuffered formaldehyde (pH 7.4) for 48 hours and subjected to routine tissue processing procedures to obtain 4 gm thin sections that were stained routinely by H & E for histopathological examination and immunohistochemically by monoclonal antibodies labelled by streptavidin-biotin peroxidase complex to visualize lymphocyte subsets BoCD21+, BoCD4+, BoCD8+ and BoWCl+. Rectal temperatures differential leukocyte count. Each of the infected animal was humanely started to increase above normal by day 8 post infection while ECF was confirmed by lymph node smear examination by day 7 and dyspnea by day 15 post infection. It was demonstrated that the majority of lymphocyte subsets infiltrating the lungs of cattle infected with Theileria parva are BoCD4+ and BoCD8+ in the acute and advanced stages of ECF, respectively. The BoCD8+ T cells were about eleven times more than the rest of the other subsets in the naturally infected animals slaughtered in the advanced stages of ECF. The apparent higher mean number of both BoCD21+ and BoWCl+ during midway of the course of infection suggests that these may have more roles to play in this stage than in the advanced stages of Theileria parva infection. Notwithstanding the mechanisms that attract these lymphocytes into the lungs, their presence indicates that they likely bring about local release of cytokines that contribute towards development of inflammation and pulmonary edema. It was concluded that any endeavour to develop ways to treat Theileria parva infection should study the specific cytokines released during ECF
Incidence and management practices of bacterial meningitis in children in Morogoro regional referral hospital
(Sokoine University of Agriculture, 2013) Chambuso, Ramadhani
The analysis and evaluation of meningitis situation in Morogoro Region was done by looking at the incidence and management practices of meningitis in children at the Morogoro Regional Referral Hospital (MRRF) for a period of 7 months. A total of 1352 children aged between 7 days and 12 years were admitted at MRRH, of these 72 (5.3%) had meningitis symptoms during the period. Lumbar puncture was done on the 72 children with meningitis symptoms to collect CSF for observation and laboratory analysis. Of the examined CSF samples, 23 (31.9%) were positive for Streptococcus pneumoniae, 6 (8.3%) for Haemophilus influenzae, 5 (6.9%) for Group B Streptococcus, 3 (4.2 %) for Echerichia coli and one (1.4%) was AFB positive on Ziehl-Neelsen (ZN) stain. Thirty nine percent (n=72) of the samples showed no bacterial growth in the culture media. Latex agglutination test was used to confirm the bacterial colonies. The incidence of meningitis infection was 5.3% (n=1352) among the admitted patients. Intravenous administration of Ceftriaxone at 80mg/kg body weight was given once a day for 10 days to all the 72 children with symptoms of meningitis. Of the 72 treated children, 32 (44.4%) responded well to the treatment of whom 19 (26.4%) fully recovered, while 13 (18.1%) recovered but with neurological defects. Nevertheless, 39 (54.2%) of the treated children did not respond to the therapy whereas 31 (43.1%) of them died while 8 (11.1%) were referred to the Muhimbili National Referral Hospital. Only one case of Tuberculosis (TB) Meningitis was recorded which responded well to TB medication of rifampicin, isoniazid and pyrazinamide in a combination. This study has shown that Streptococcus pneumoniae was the major bacteria associated with meningitis in children admitted at the MRRH.
Immune response to new plasmodium falciparum liver stage antigens in children naturally exposed to malaria
(Sokoine University of Agriculture, 2009) Mkindi, Catherine Gerald
Interferon gamma (IFN-y) responses to Human Leukocyte Antigen (HLA) class 1 restricted peptide antigens have been shown to be protective against malaria in different populations where malaria is endemic. The present study examined whether newly discovered liver stage Plasmodium falciparum (P. falciparum) protein antigens, which were matched to different HLA class 1 alleles predicted to be expressed by Tanzanians, can stimulate T cells with subsequent production of IFN-y. A crossectional study from an ongoing cohort of children between the age of 0-5 years in malaria endemic area of Morogoro municipality, Tanzania, was undertaken to test IFN-y responses to the new liver stage antigens. To examine whether the these liver stage peptides stimulated T cell proliferation and IFN-y production, an enzyme linked immunospot (ELISPOT) assay was used, and results were compared to parasitological and haematological parameters of the children investigated. HLA B15 predicted specific responses were most frequent 63.6%, (21/33) when compared to responses to peptides predicted to be restricted by other HLA class 1 alleles such as HLA B35 22% (4/18) and HLA A02 15.2% (7/49) (P<0.05) by a chi square test. Children below 6 months were found to respond to the peptide antigens less frequently (7.2%, 5/70) than children above 6 months (92.8%, 65/70) (P=0.0001). Moreover, responding children above 6 months (78.8%, 26/33) were found to be protected from malaria parasitemia within two months follow up period, P=0.0003. This study confirms the presence of adaptive cell-mediated immunity to the liver stage malaria antigens in children from Tanzania and demonstrates that alleles of the HLA-B15 can effectively present antigenic epitopes. These antigens therefore provide suitable candidates for inclusion into the pool of pre-erythrocytic antigens for malaria vaccine candidates.
Investigation of oxytetracycline use and abuse: determination of its residues in meat consumed in Dodoma and Morogoro municipalities
(Sokoine University of Agriculture, 2004) Mmbando, Louis Mshakale Gregory
In spile of oxytetracycline (OTC) being a widely used drug in livestock production in Tanzania for many years, there is no published information on its use and occurrence of its residues in the meat consumed in the country. This study was aimed at establishing the mode of OTC use, the occurrence and levels of its residues in the meat consumed in Dodoma and Morogoro regions. The mode of OTC use was studied by the administration of a questionnaire to respondents in some of the slaughter cattle catchment areas. The residue occurrence levels were accomplished by analysis of 131 muscle, liver and kidney samples by using the high performance liquid chromatography (HPLC) technique. OTC sample extraction was done using a pH 4.0 Mcllavaine-EDTA buffer and cleanup by application on Supelclean LC-18 solid phase extraction (S.P.E.) cartridges. OTC quantification was done by using an ATIUNICAM H.P.L.C. system with an electron capture UV detector set at 350nm. The separation of OTCs was carried out by an RP 8-10 Lichrosorb (4.6 mmd x 25cm) column and a Methanol: Acetonitrile: O.OlMaq. Oxalic Acid mobile phase in the ratio 1:2:7 V/V/V, respectively. The study established a high degree of OTC abuse of use especially by the livestock keepers through overdosing by as much as 10-20 times the recommended therapeutic doses, use of wrong routes of administration, arbitrary drug combinations and non-observance of the OTC withdrawal period. Out of the 131 beef samples analysed, 54 (41.2%) had detectable OTC residues. Furthermore 41 (31.3%) samples had violative OTC residues levels compared to the FAO/WHO 1999 OTC maximum residue levels (MRLs) of 0.2 mg/kg (muscle), 0.6 mg/kg (liver) and 1.2mg/kg (kidney). Violative OTC residues ranged from 0.52 mg/kg to 8.98mg/kg of tissue. The 31.3% violative samples, coupled with the high mean OTC residue concentrations observed were very significant compared to those of other countries. It is an indication of the seriousness of the OTC abuse problem with its attendant residue occurrence and harmful effects on public health, our international trade of animal products and the environment. Deliberate steps need to be taken by the state to redress the situation before it gets worse.
Effectiveness of health education intervention for controlling porcine cysticercosis in Kongwa and Songwe districts, Tanzania
(Sokoine University of Agriculture, 2024) Wilson, Christina
Taenia solium taeniasis/cysticercosis (TSTC) is a parasitic zoonotic disease that is endemic in several developing countries in sub- Saharan Africa, Latin America, and East and Southeast Asia. Tanzania is one of the developing countries where the parasite has major negative effects on the economy and public health. Based on previous reports in Tanzania, the disease is widespread in the central region,the northern and southern highland regions. Several studies on disease control have been conducted in Tanzania. Interventions for health education have been conducted with promising results. However, prior health education was characterized by limited community engagement, which could lead to limited sustainability. This study used a health education package (HEP), which was co- created with community participation to ensure knowledge uptake and sustainability for controlling porcine cysticercosis in Kongwa and Songwe Districts in the central and southern highland regions of Tanzania, respectively. Three phases of data collection were used in the study: first, a baseline survey was conducted between June and September 2019 in 42 villages (28 in Kongwa and 14 in Songwe districts), followed by a community health education intervention between October and December 2020 in 21 villages (14 in Kongwa and 7 in Songwe district). The second survey of data collection was conducted one year after a community health education intervention between October and December 2021 in all 42 villages. A cross-sectional study was conducted in a baseline survey to assess farmers’ knowledge, attitudes, and practices (KAP) related to the transmission, prevention, and control of PCC and also assess the seroprevalence of porcine cysticercosis (PCC). The survey was administered using a Kobo toolbox. The interview was conducted in the village office, followed by a household survey to evaluate and verify hygiene and sanitary practices. A total of 692 smallholder pig farmers were interviewed. To assess the seroprevalence of PCC, about 5 ml of blood samples were collected from 692 pigs through a jugular vein using a plain vacutainer tube. Later, the sera were harvested, and using a cysticercosis Ag-ELISA kit, the parasite's circulating antigens were detected. The villages were then stratified into three strata based on the comparability of the PCC seroprevalence measured at baseline using Ag-ELISA. The first stratum consisted of 10 villages with zero seroprevalence. The second stratum consisted of 13 villages with a seroprevalence of 4.5% to 9.5%. The third stratum consisted of 19 villages with a seroprevalence of 10.5% to 33.3%. Half of the selected villages in each stratum were randomly assigned to either the intervention or control groups. Twenty-one villages with 361 households were allocated to the intervention (treatment) group, whereas the other 21 villages with 331 households were allocated to the control group. After the baseline study, a community health education intervention trial was administered to the intervention group using leaflets, posters, and booklets. The health education was conducted in two phases. Phase one involved a two-day training of the trainers (ToT), which included village and ward leaders, livestock, and human health professionals. Phase two involved a one-day training of the pig farmers by the selected ToT. A second survey was conducted one year following the community health education intervention using the same data collection instruments as in the baseline survey. The baseline survey showed that 72% (n = 692) of respondents had heard about porcine cysticercosis (PCC), approximately half (42% (n = 692) of the respondents had little knowledge regarding PCC, and only 34% (n = 692) were aware that pigs can acquire PCC by ingesting human faeces with T. solium eggs. Approximately 36% (n = 692) of the respondents could identify cyst-infected pigs. About 72% had a positive attitude toward PCC prevention and control measures. Approximately 64% (n = 692) of the respondents believed that cyst- infected pork should be outlawed. In addition, 59% of respondents (n = 692) thought that using latrines with functional doors might reduce the occurrence of PCC. The majority of smallholder pig farmers (73%) acknowledged consistently deworming their pigs; 85% of respondents admitted to deworming themselves and their family members each year. The two drugs that are frequently used to treat worms in humans and pigs are albendazole and ivermectin, respectively. In addition, 92% of households in the districts had latrines, and around 28% (n = 692) of the pigs were raised in free-range environments. Ag-ELISA results showed that 67 (9.7%) pigs had PCC. In Kongwa and Songwe districts, the seroprevalence was 7.3% and 14.0%, respectively. In addition, the baseline seroprevalence of PCC was 10.2% and 9.1% in the intervention and control groups, respectively. Twelve months after community health education, the differences in difference analysis found that health education increased the knowledge level (β = 1.779, p = 0.004), attitude level (β = 1.024, p =0.038), and practice level (β = 0.719, p = 0.023) over time. In addition, the study found an increase in knowledge of the transmission of porcine cysticercosis by 41.5% (p <0.001) and 11.3% (p = 0.011) in pig farmers in the intervention group and control group, respectively. Further, the study found improvements of 14.5% (p <0.001) and 3.5% (p = 0.034) in farmers’ desire to condemn cysticerci-infected pork in both the intervention and control groups, respectively. Furthermore, the study observed that PCC seroprevalence decreased to 0.5% and 3.9% in the control and intervention villages, respectively, although the decrease was not statistically significant in both groups. The study showed that PCC was still prevalent in the area and that farmers’ knowledge about the disease was poor, and risky practices were present. The community health education intervention using the HEP has improved the knowledge, attitudes, and practices of smallholder pig farmers toward PCC transmission and control; however, the short observation period compromised the power of the study to definitively attribute the reduction of PCC seroprevalence to the interventions. Therefore, the study recommends that, future research to integrate health education interventions with treatment of human taeniosis, which could be an important step to immediately interrupt the lifecycle of T.solium which may have helped to see the larger short-term effects of health education interventions
Effect of blood-host plasticity on life history traits of tropical bed bugs species from selected areas of Tanzania
(Sokoine University of Agriculture, 2024) Mwamundela, Baraka Edson
Bed bug infestations are on the rise worldwide, turning them into a bothersome pest with serious public health implications. Furthermore, due to high resistance to insecticides, the control of bed bugs is increasingly becoming a challenge. However, little is known about their life history characteristics and microbial community when they consume different blood meals. Understanding their life history characteristics as well as bacterial diversity and composition are necessary in informing their epidemiology as well as management and control strategies. Therefore, this study aimed to assess i) the effect of host‘s blood meals on life history characteristics namely survival, fecundity hatchability and development and (ii bacteria composition and diversity. Bed bugs (cimex hemipterus) collected from the field were reared on mice blood meal source in an insectary and thereafter second filial generation was used in this study. Each cohort contained ten (10) bed bugs with a 1:1 sex ratio and was replicated three (3) times for each of the five different hosts. As such, a total of 30-bed bugs were blood-fed on each of the host species. The bed bugs were allowed to feed on different host species for 10 minutes every two days and mortality, fecundity, hatchability and development were recorded, thereafter. A subset of one-bed bug per group was selected to assess the bacteria composition. After DNA extraction, metagenomic was used to sequence the microbiome of each bed bug group. Human-fed bed bugs had higher survival rate compared to those fed on mice, rats, guinea pigs and bats (in decreasing order). Similarly, the fecundity of human-fed bed bugs (248 eggs) was relatively higher than those fed on mice (212 eggs), rats (118 eggs), guinea pigs (97 eggs), and bats (88 eggs). The hatchability of eggs was proportionally higher in bed bugs fed on humans (n=54, 91%) than those fed on mice (n=44, 73%), rat (n=40, 67%), guinea pig (n=40, 67%) and bats (n=39, 65%). Furthermore, Human-fed bed bugs (nymph) survival was slightly observed to be higher on human-fed bed bugs compared to those fed on mice, rats, guinea pigs and bats ( in descending order) and development from one instar to another was frequently observed on bed bugs fed on humans, followed by mice rats and bats-nymph was the least. Hemoglobin concentrations from the host have demonstrated a significant negative correlation with survival, fecundity and hatchability. The metagenomic show that only phylum Proteobacteria was dominant with 158011 sequences of microbial composition, of which Wolbachia was the most dominant genera with 136134 (86.15%) sequences, followed by Pectobacterium with 21708 (13.74%) sequences. The Wolbachia genus had three strains: Wolbachia1, Wolbachia2, and Wolbachia3. These accounted for 85.03% (134,367 sequences), 1.08% (1,701 sequences), and 0.04% (66 sequences) respectively of the Wolbachia diversity in our samples. Interestingly, we only found two pathogenic genera: Salmonella with 158 (0.1%) reads and Massilia with 11 (0.01) reads. In conclusion, the results herein indicate that blood-meal source affects the life-history traits of the bed bug species Cimex hemipterus. Bed bugs fed on humans showed the highest survival rate, fecundity, hatchability and development relative to those fed on mice, rats and guinea pigs. Our findings indicate that bed bugs feeding on humans have greater microbial diversity compared to those feeding on guinea pigs, rats, mice, or bats Furthermore, these results will potentially inform further studies aimed to understand their epidemiology as well as the management and control strategies.
Antimicrobial resistance pattern of escherichia coli and salmonella species, isolated from domestic and peridomestic rodents in Iringa municipality, Tanzania
(Sokoine University of Agriculture, 2024-05) Mkopi, Jackson Chrispin
Escherichia coli (E. coli) and Salmonella species are two of the most common causes of foodborne illness worldwide. E. coli is a Gram- negative bacterium that is found in the intestines of humans and animals. Most strains of E. coli are harmless, but some strains can cause serious infections, such as food poisoning and urinary tract infections. Salmonella species is a gram-negative bacterium that is found in the environment and in the intestines of animals. Salmonella species can cause a variety of infections, including gastroenteritis, typhoid fever, and paratyphoid fever. Antimicrobial resistance is a major concern in the treatment of E. coli and Salmonella infections. When E. coli and Salmonella species become resistant to antimicrobials, they are more difficult to treat, which can lead to more severe infections and even death. Rodents are known to be reservoirs of E. coli and Salmonella spp. bacteria. Rodents can transmit E. coli and Salmonella spp. to humans and other animals through their faeces, urine, and saliva. The aim of this study was to determine the prevalence and antimicrobial resistance pattern of E. coli and Salmonella spp. isolated from domestic and peridomestic rodents in Iringa, Tanzania. A cross-sectional study design was used in this study. The study sites possessing favourable rodents habitats were purposively selected. A total of eight wards (sampling sites) were selected. The target study population was rodents, a total of 153 rodents were trapped in Iringa municipality, Tanzania. The rodents were trapped in both domestic and peridomestic settings. Following euthanization, rats were identified to genus/species level using morphological and morphometric features. Faecal swab samples were collected from the rodents and pre-enriched in buffered peptone water, followed by culture and biochemical tests for identification of E. coli and Salmonella spp. Molecular confirmation tests were done using 16RrRNA PCR identification methods. The antimicrobial susceptibility test was performed by disk diffusion method comprising five antimicrobials, including tetracycline (30μg), ciprofloxacin (5μg), gentamicin (10μg), ceftriaxone (30μg), and trimethoprim-sulfamethoxazole (25μg). Seven resistant genes were analyzed by PCR, which were blaCTX-M, blaSHV, sul1, sul2, tetA, acr(A), and aac(3)-1 in each isolate. Three rodent species, Rattus rattus (75.2%), Mastomys natalensis (23.5%), and Mus musculus (1.3%), were captured. 17 (11.1%) E. coli were detected, and no Salmonella species were isolated. All 17 isolates were susceptible to Gentamycin, while Sulphamethaxazole/Trimethoprim was highly resistant (52.9%). Four E. coli isolates exhibited multidrug resistance (MDR), whereby 75% of these MDR isolates originated from the same area. Six resistant genes were detected: blaCTX-M, sul1, sul2, tetA, acr(A), and aac (3)-1, where the acr(A) resistant gene was the most abundant. There were co-occurrences of the resistant genes per isolate such as sul2, acr(A), and aac(3)-1. This study reveals the antimicrobial resistance of E. coli isolated from rodents, providing preliminary data on the prevalence and antimicrobial resistant features of these pathogens in their respective reservoirs in Iringa municipality. The study recommends observation of regular antimicrobial resistance screening and improvement in rodent management and control programs in the studied area.
Influence of variations in species and host physiological attributes on olfactory response and reproductive performance of female adult ornithodoros moubata
(Sokoine University of Agriculture, 2024-05) Mohamed, Mariam Said
ick-borne relapsing fever (TBRF) poses a significant threat to public health, particularly in Tanzania, where it causes high mortality rates in children under five and disrupts the health of pregnant women. Pervasiveness of this disease has raised the need to understand behavioural response of the ticks to their reservoir hosts. To effectively combat this disease, it is crucial to understand the behavioural responses of the vector, Ornithodoros moubata, to its various host species. This study delves into this intricate relationship, exploring the impact of host characteristics and species on the tick's olfactory response and feeding behaviour. Additionally, despite the evident role of climatic, anthropogenic, and biological factors in increasing the risk of recurrent TBRF outbreaks in many African countries like Tanzania, there is a significant lack of comprehensive data from studies elucidating intra-species variations in the feeding and reproduction patterns of the primary vectors (O. moubata) across diverse hosts. The first part of the study investigates the influence of physiological factors such as age, sex, and weight of white mice on the tick's attraction. Additionally, it examines the attractiveness of different host species, including Mus musculus, Mastomys natalensis, Rattus rattus, and Gallus gallus domesticus, to O. moubata. The second part focuses on intra-species variations in the feeding behaviour and reproductive performance of O. moubata across different hosts, including mice, rats, and chickens. This comprehensive analysis sheds light on the tick's host preferences and provides valuable insights for developing effective control strategies against TBRF and other tick-borne diseases. The assessment of effects of physiological status specifically age, sex, and weight of white mice and different host species on the olfactory behavioural response of O. moubata, initially involved obtaining an adult colony to be utilized in the experiment from the Tanzania Plant Health and Pesticide Authority (TPHPA). 15 (10 males and 5 females) ticks were introduced through the release chamber in the middle of each olfactometer and allowed to select the test stimulus/host for 12 hours over night. The numbers of ticks trapped in both arms and the release chamber was counted. Each dual choice mode was composed 12 olfactometers. The experiment had five replicates per three of the four choice dual choice modes employed (fixed age, fixed sex and varying age and sex) while remaining dual-choice mode (varying hosts) had six replicates. The number of ticks trapped in both arms of the olfactometer was the measure of attractiveness. Results revealed that mice sex (P = 0.028) and low weight (P < 0.001) to be highly associated with O. moubata attraction. Slight significant attraction was observed in 45 days old mice (P = 0.045). Gallus gallus domesticus was most attractive compared to white mice. Additionally, only sex and weight interaction had positive correlation to attraction of O. moubata (P= 0.020). Additional testing is required to evaluate exact age, weight, and the species dependent response as well as the role of mice skin microbiota on attraction of O. moubata. On the other hand, the second part of the study focused on assessing intra-species variations in the feeding and reproduction patterns of O. moubata across different hosts in a controlled lab experiment. Employing a cross-sectional experimental study design, the controlled-lab experiment sought to examine differences in feeding behaviours and reproductive success of the ticks exposed to various host species including Mus musculus, Mastomys natalensis, Rattus rattus, and Gallus gallus domesticus. Descriptive and inferential analysis of the generated data was performed using the R Software Version 2023.12.1. The study revealed that O. moubata exhibited the highest feeding success on Rattus rattus, indicating a preference for this host species. However, the results lacked statistical significance, emphasizing the necessity for further research to confirm host preference. Additionally, the study uncovered host-specific feeding behaviour and reproductive success in O. moubata, with Gallus gallus domesticus being the most favorable host for egg production compared to others. Given the potential impact on disease transmission and pest control, it is crucial to investigate the underlying factors influencing the preference of the ticks for Rattus rattus, necessitating exploration of strategies to mitigate their impact. Furthermore, additional research into the physiological and ecological factors affecting tick feeding efficiency and host-specific variations is warranted.
Assessment of dichapetalum plants infestation and its susceptibility to three herbicides in Mkuranga district Tanzania.
(Sokoine University of Agriculture, 2007) Mopei, Nassoro Athumani
A study was conducted in Mkuranga District between October, 2005 and February, 2006 to investigate Dichapetalum plants infestation and effectiveness of selected herbicides on these plants. Specifically, this study intended to identify species prevalence and their coverage in this District. The study further aimed at determining effectiveness of herbicides on the control of Dichapetalum plants. The Purposive sampling was used to select farms for the study. The actual areas of infestation for surveys in these farms were chosen on random basis so as to get representative picture for whole area infested with these plants in the District. The survey conducted using Scientific Quadrant Method, established presence of four Dichapetalum species; Dichapetalum stuhlmanii, Dichapetalum mossambicence, Dichapetalum ruhlandii and Dichapetalum arenarium, with percentage cover of 76%, 42%, 37% and 27% respectively. The plants that were commonly in close association with Dichapetalum plants were Deinbollia borbonica, Annona senegalensis, Xylotheca tetensis and Milletia spp. Dichapetalum plant sprouts were individually sprayed with 2,4-dichlorophenoxy acetic acid (2,4-D), glyphosate (Round up®) and paraquat in the field, followed by observation for responses to herbicides for 60 days. A number of phytotoxic effects were recorded. The efficacies of selected herbicides were assessed in terms of killing percentages. Killing percentages recorded at the end of study (Day 60) were analyzed by MSTAT-C. Overall killing percentage was 16.2 %. On individual herbicide, paraquat recorded the highest killing percentages (17.8 %) among the three tested herbicides. This was followed by 2,4-D (16.3 %). Glyphosate recorded killing percent of 14.6 % which was the lowest in the study. Analysis of variance (ANOVA) has shown that the degree of control on Dichapetalum plants is influenced by herbicide type, dosage rate, and interaction between herbicide and dose. It was concluded that Mkuranga District is heavily infested with Dichapetalum plants and application of 2,4-D, Glyphosate and Paraquat in dry conditions gave poor herbicide performance.
Mechanisms of gestational diabetes mellitus using rat model
(Sokoine University of Agriculture, 2024) Mbepera ,Saada .
Gestational diabetes mellitus (GDM) is a form of hyperglycemia due to carbohydrate intolerance that begins during pregnancy. This may be due to insulin resistance or impairment of insulin secretion during pregnancy. Knowledge on the pathophysiology of GDM is important for its management. Thus, the main objective of the current study was to explore the mechanisms of GDM development due to high fat diet (HFD) or heat stress (HST) in a rat model. Specifically, the study was done to evaluate the role of differential adipose tissue (AT) expansion, influence of oxidative stress (OS) and to determine the role of placental cytokine (tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)) in the development of GDM. The study used Wistar rats as experimental animals. Rats of 8 - 10 weeks old were used and experiments were conducted at the Small Animal Research Unit (SARU), College of Veterinary Medicine and Biomedical Science (CVMBS), Sokoine University of Agriculture (SUA), Morogoro, Tanzania. Samples were analysed in research laboratories in the Departments of Physiology, Biochemistry and Pharmacology and Veterinary Anatomy and Pathology. This thesis is divided into three chapters. Chapter one is on introduction and literature review. It includes a general introduction, animal models for GDM, factors governing the development of GDM, establishing GDM models, histopathology of pancreas during GDM, placenta and GDM, objectives of the study, and organization of the thesis. Chapter two comprises three manuscripts describing the research findings. The first manuscript describes the contribution of HFD to the development of GDM. The second manuscript is on evaluation of how OS due to HST predisposes rats to GDM. Findings on assessment of theiv role of placental cytokines (TNF-α and IL-6) in the development of GDM are presented and discussed in the third manuscript. Lastly, general discussion, conclusion and recommendations of the study are provided in chapter three. Work described in the first manuscript evaluated contribution of HFD in differential AT expansion and subsequent development of GDM in Wistar rats. Pregnant and non- pregnant rats were given streptozotocin (STZ) by a single intraperitoneal injection or HFD throughout the experiment. The animals were sacrificed by a combination of ketamine 50 mg/kg and xylazine 5 mg/kg on days 1, 8, 15, and 21 of the experiment. Blood, AT (both visceral (VAT) and subcutaneous (SAT)) and pancreas were collected and analysed. In this study, STZ-treated animals had a significant increase (p<0.05) in serum glucose and a decrease in insulin, without changes in the size of adipocytes. The levels of both serum glucose and insulin were significantly high in HFD-fed animals (p<0.05); being higher in pregnant (p<0.05) than non-pregnant rats. The increase in glucose and insulin levels was associated with an increase in the size (hypertrophy) than the number (hyperplasia) of adipocytes. The increase in adipocytes was higher in VAT and corresponded to insulin resistance and GDM development than in SAT. Histologically, β-cells were decreased in number and deformed in STZ groups while maintained in HFD groups in both pregnant and non- pregnant animals. This study concluded that intake of HFD during pregnancy leads to AT expansion, which is one of the risk factors for the hyperglycemia and development of GDM. This study demonstrates in the second manuscript the association between HST and GDM. Pregnant and non- pregnant Wistar rats were maintained at 41 - 42°C for 21 days. On days 1, 8, 15 and 21 the animals were humanely sacrificed by a combination of ketamine 50 mg/kg andv xylazine 5 mg/kg. Blood samples were collected from the heart for glucose, insulin, malondialdehyde (MDA) and glutathione peroxidase (GPx) analyses. Pancreatic tissues were fixed in neutral buffered formalin, and processed for histopathology. The findings demonstrated that, in pregnant rats, HST induced a significant increase in glucose in conjunction with a drop in insulin levels than non-pregnant rats (p<0.05). In addition, heat treatment was accompanied by an increase in MDA and a drop in GPx levels. Histological examinations of the pancreas revealed damaged β-cells from day 15 and a reduction in the number of β-cells by day 21 of the experiment in pregnant rats. These results suggest that HST raises the levels of OS in pregnant rats more than in non-pregnant rats and increases the chances of GDM as it is associated with β-cell defects in the pancreas. Findings on serum concentration and placental production of TNF-α and IL-6 of HFD-given rats during pregnancy and their correlation with the development of GDM are presented and discussed in the third manuscript. Pregnant and non- pregnant rats were given STZ single IP injection or HFD throughout the experiment. On days 1, 8, 15 and 21, the animals were humanely sacrificed by a combination of ketamine 50 mg/kg and xylazine 5 mg/kg. Blood samples were collected from the heart for glucose, insulin, TNF-α and IL-6 analyses. Placenta samples were dissected, fixed in neutral buffered formalin, and processed for histopathological and immunohistochemical analyses for TNF-α and IL-6. The levels of serum glucose and insulin were significantly high in HFD-fed animals (p<0.05); being higher in pregnant (p<0.05) than non-pregnant rats. The increase in glucose and insulin levels was associated with an increase in serum levels of TNF-α and IL-6; which were higher in HFD pregnant than non-pregnant animals on day 21 of the experiment. Histologically, placenta tissues of STZ- treated animals were severely congested with blood vesselsvi on days 15 and 21 compared with those from HFD-fed rats which had low congestion on day 21. In both pregnant and non-pregnant rats, immunostaining intensity for TNF-α and IL-6 was high in HFD and STZ-treated animals on day 15 and 21. The findings of this study show that intake of HFD during pregnancy leads to an increase in the levels of IL-6 and TNF-α in the placenta towards the end of gestation resulting in insulin resistance and hyperglycemia that may predispose to GDM. Therefore, Intake of HFD during pregnancy causes AT expansion as well as increase in the levels of placental cytokines (TNF-α and IL-6) resulting in insulin resistance and hyperglycemia, which are risk factors for GDM development. In addition, exposing rats to HST during pregnancy raises the levels of OS which is associated with β-cell defects hence increasing the chances for GDM.
Bionomics, blood-host plasticity and its effect on host-choice and feeding behaviour of tsetse species from selected human- wildlife interface in Tanzania
(Sokoine University of Agriculture, 2024-04) Mdee, Filbert Ewald
Tsetse flies are vectors of trypanosome parasites which cause human African trypanosomiasis (HAT) in human and African animal trypanosomiasis (AAT) in livestock across Sub-Saharan Africa. These flies feed exclusively on animals’ blood. It is during blood- feeding process of these flies; un-infected host get infected by parasites carried by infected vector. Several tsetse controls programs have been implemented so as to minimize the incidences of trypanosome infections; however, the human-wildlife interfaces remain as the risk areas where both livestock and human being can be infected with trypanosome parasites. Therefore, surveillance and control of these flies is important so as to minimize the African trypanosomiasis’ risks in these areas. This study assessed the species composition, abundance and phylogenetic relatedness of wild collected tsetse flies from selected human-wildlife-livestock interface in Tanzania. Variation in host choice and feeding behaviours of predominant species’ (Glossina morsitans) siblings whose parents were blood-fed on different host species were also investigated. The tsetse flies were trapped seasonally in two selected wards within Morogoro Rural district. The study wards and villages were purposively selected targeting those which are bordering to protected areas. In each ward, baited NZI, Pyramidal and Biconical traps were deployed at 200m distance apart from each other for 72 hours before rotating to the next trapping sites. Trapped flies were collected from the traps after 24 hours then identified morphologically and later confirmed using the Polymerase Chain Reaction (PCR). Moreover, a colony of tsetse flies were established from pupa obtained from tsetse and vector control centre, Tanga. Hatched flies were maintained on selected hosts blood until the offsprings were obtained for the experiments. The host-choice and feeding behaviours experiments were carried out in large semi-field cage containing four small equal size screen cages. During the experiments, individual host was placed in a screen cage which allowed flies to enter through openings on each side. The groups of flies (20 per replicate) colour-marked differently basing on their parents’ bloodmeal hosts, were released from the centre of large semi-field cage and left to forage for 24 hours before being collected, then, sorted basing on the location, feeding status and parents’ bloodmeal. The total of 784 tsetseflies were collected; Glossina pallidipes (n=371; 47.32%) and Glossina morsitans morsitans (n=413; 52.68%). Of these, 96 flies (80-female, 16-male) were blood-fed; 57(48-female and 9-male) G. pallidipes and 39(32- female, 7-male) G.m. morsitans. Overall abundance of collected tsetse significantly varied across surveyed wards (χ2=4.597, df=1, p= 0.032), villages (χ2=9.491, df=3, p= 0.023), habitats (χ2=17.239, df=2, p<0.001), months (χ2=13.507, df=3, p= 0.004) and deployed traps (χ2=6.348, df= 2, p= 0.04). About 78.82% of tsetse flies were collected from Kisaki ward (n=618; p<0.001) and 21.17% (n=166; p=0.032) from Bwakila chini. The highest proportion of these flies were collected in Mbojoge village (62%; n= 489) followed by Kiperege (18%; n=141) and Sebo (16%; n=129). NZI traps collected the highest proportion of tsetse flies (n=422; 54%; 4.98 FTD) followed by Pyramidal traps (n=281; 36%; 4.01 FTD) and Biconical traps (n=81; 10%; 1.87 FTD). Similarly, the large proportion of tsetse flies (78.06%) were collected in bushed grassland habitat (n=612; 55.41 FTD) followed by woodland habitat (16.45%; n=129; 20.56 FTD) and farmland (5.5%; n=43; 7.17 FTD). The phylogenetic analysis revealed genetic relatedness of tsetse flies collected in Tanzania with those collected from Nigeria and Senegal. Furthermore, a total of 213 flies (72.95% of the recovered) were attracted to the hosts. The number of flies attracted to different hosts varied significantly (χ24= 33.685, p= 0.0001); Rodent (n=80, p=0.006), Rabbit (n=59, p=0.331), Guinea pig (n=49, p=0.057) and squirrel (n=25, p=0.005). The number of flies attracted to their parent’s blood meal source varied significantly (χ212 = 56.476, p<0.001); rabbits (n= 35, 59.32%, p<0.001), rodent (n=25, 31.25%, p=0.043) and guinea pig (n= 19, 38.78%, p=0.45). But, only 39 flies (18.31% of total attracted) bloodfed on the hosts; Guinea pigs (n=10, 25.64%), Rodents (n=23, 58.97%), Rabbits (n=6, 15.38%) and Squirrels (n=0,0.0%). There was significant variation in number of flies that fed successively across hosts (χ24=49.478, p<0.001). The present study recommends NZI and Pyramidal traps for tsetse fly control at the interface and wet season as appropriate season for conducting control activities. Also, the study confirms the presence of the hosts’ differential attractiveness to flies but failed to explain observed behaviours in relation to genetic inheritance. Therefore, future studies are recommended to investigate the effect of bloodmeal sources on tsetse fly siblings’ behaviours across filial generations using small mammals.
Prevalence of leptospirosis in livestock, rodents, and shrews in Kilwa district of Southern Tanzania
(Sokoine University of Agriculture, 2024-04) Kikoti, Mathayo Cralency
Leptospirosis is a globally resurgent zoonotic disease that affects both humans and animals, with occurrences widespread in tropical and sub-tropical regions. Tanzania, located in Sub-Saharan Africa, is among the tropical countries grappling with the burden of leptospirosis in both human and animal populations. Following the reporting of 20 confirmed symptomatic cases and 3 deaths, the Tanzanian Ministry of Health (MoH) declared the outbreak of leptospirosis on July 5, 2022. The main objective of this cross- section study was to determine the prevalence of leptospirosis by using the Microscopic Agglutination Test in Rodents, shrews and livestock (Cattle, Goats, and Sheep) in Kilwa district of southern Tanzania. Blood samples were collected from 100cattle, 120goats, 20 sheep and 202 small mammals (Rodents and shrews) in Kilwa district in selected villages for decanting sera. The serum samples harvested were tested against five Leptospira live antigens to detect Leptospira antibodies through Microscopic Agglutination Tests. In this study, five leptospiral antigens that were reported in Tanzania were employed such as Sokoine, Pomona, Hebdomadis, Lora, and Grippotyphosa. The overall prevalence of leptospirosis in cattle was 26%=95%CI=0.1774-0.3573, in goats was 27.5%=95%CI=0.1975- 0.3640, in sheep was 30%=95%CI=0.1189-0.5428 .and prevalence of small mammals was 14.36%=95%CI=0.0983-0. 1996. Among the small mammals, 61.2% of the sample tested positive for leptospiral serovars and were from Mastomys natalensis, making it a more prevalent species. Serovars Sokoine was more prevalent than all tested serovars. Most of the antibody titers obtained ranged from 1:20 to 1:80, suggesting prolonged infection. Livestock demonstrated also a high prevalence of leptospirosis with serovar Sokoine being the most prevalent serovar. Some of the leptospirosis antibodies were low, suggesting chronic infection, but others tested with high titers, which suggested new infection of leptospirosis, especially in goats. Logistic regression was also performed to determine the association between Leptospiral antibody infection and different characteristics such as sex, location, host, and serovars with P= 0.0086. There was a significant association between the leptospiral infection and serovars Sokoine and Grippotyphosa with P=0.0073, nevertheless, there was no significant between the disease with other characteristics such as sex, host, location and serovars This present study suggests that leptospira infection is a matter of public health concern as it is associated with different burdens from animals and humans, decreased livestock economy to livestock keepers due to the death of livestock animals, and decline in milk production, death of people following outbreak as it reported in Tanzania. Increased contact between human and their animals suggests possible transmission of leptospirosis in Kilwa district the southern, Tanzania. Therefore, control of the disease is inevitable to reduce the burden of the disease.
Brucellosis in humans, livestock and rodents in Unguja, Zanzibar
(Sokoine University of Agriculture, 2023-05) Njau, Gloria Peter
Brucellosis is a globally significant zoonotic disease with profound economic and public health implications. Brucellosis in humans is characterized by intermittent fever. In Zanzibar, despite the decline in malaria, fever cases persist in human population. However, limited information exists regarding brucellosis in Unguja, encompassing both humans and animals. A cross sectional study was conducted at Unguja Island between July and November, 2022 to determine the seroprevalence of brucellosis in humans and animals and assess knowledge, awareness, and community practices related to its transmission and control. Prevalence of human brucellosis was determined by analyzing 405 human serum samples from three hospitals. Seroprevalence of animal brucellosis was determined using 247 cattle, 130 goats, and 32 sheep serum samples collected from farms across five districts, alongside 384 rodent serum samples from farms, households, and marketplaces in seven districts of Unguja. The sera were screened using the Rose Bengal Test (RBT), and confirmed by indirect ELISA (i-ELISA). A structured questionnaire was used, on a purposively selected population (n=236) based on willingness of participants and their close association with keeping livestock in all seven districts of Unguja who were residents for their knowledge, awareness and practices related to occurrence and transmission of the disease. For human brucellosis, 153 participants were assessed for their knowledge, awareness and control measures towards the disease by using the structured questionnaire. The study found a lower prevalence of human brucellosis (0.74% n=3/405) based on iELISA. Seroprevalence in cattle were 1.62% (n=4/247), goats (0% n=0/130), sheep (12.5% n=4/32), and rodents (0.26% n=1/384). From questionnaire survey, findings revealed that there is high consumption of dairy milk (92.2% n=141) with relatively low (2% n=3/153) raw milk consumption since most consume it boiled (82% n=126). Few respondents were aware of human brucellosis (28.8% n=44), and fewer identified it as a zoonosis (22.9% n=35). For the animal brucellosis questionnaire, that had a total of 83 livestock keepers, majority were male (75.9% n=63), farmers (50.6% n=42), with secondary education (39% n=47) and an age range of 18-45 years (71.1% n=59). Cattle were the predominant livestock (41% n=34), most animals (65.1% n=54) were reared under open housing system and tethering (56.6% n=47); and family members (72.3% n=60) primarily cared for the animals. The survey revealed that awareness of brucellosis was evenly distributed, with 52% (n=43) of respondents being unaware. Knowledge was primarily sourced from mass media (40%) and veterinarians (32%). Clinical signs on animals such as abortion (13% n=11) were observed. Veterinary officers played a vital role in calving/kidding assistance (55.4% n=46), and many respondents (60.2% n=50) reported using protective gear when handling sick/calving animals. Reproductive outcomes highlighted stillbirths (36.1% n=30) and abortions (33.7% n=28), with placenta retention mostly in normal deliveries (32.5% n=27) compared to abortions/stillbirths. Moreover, abortion took place at different stages of pregnancy. Most animals were also not vaccinated against brucellosis (90.4% n=75). This study concluded that human and livestock brucellosis prevalence was low in Unguja Island. Despite its rarity, the potential impact on animal productivity and human heath underscores the need for persistent surveillance and increased efforts in raising community awareness to interrupt transmission and mitigate risks to livestock and public health. Further research is also required to explore other potential causes of fever in humans, abortion in livestock and the role of rodents in disease occurrence and transmission.
Seroprevalence and molecular detection of toxoplasma gondii infection in rodents and pigs and risk factors for human exposure in Iringa municipality, Tanzania
(Sokoine University of Agriculture, 2024-04) Herman, Oscar
Toxoplasma gondii is one of the protozoan parasites of worldwide distribution causing infection to various warm-blooded animals. The parasite's life cycle requires both primary and intermediate hosts. Notably, rodents and pigs are significant intermediate hosts due to their frequent contact with humans, thereby assuming a pivotal role in the public health implications of the disease. Mortalities due to Toxoplasmosis have been documented in southern highland regions including the Iringa region. However, there is a lack of information on the disease status in rodents and pigs and risk factors for human transmission in the Iringa region. This study aimed at establishing the seroprevalence and molecular detection of T. gondii infection in rodents and pigs and risk factors associated with human exposure in Iringa municipal in Tanzania. A cross-sectional study design was adopted. The study wards were randomly for rodent sampling and questionnaire survey. Blood samples were collected from both rodents and pigs; in addition, brain samples were obtained from rodents. The antibody ELISA technique was employed on rodent and pig samples and seropositive samples were subsequently subjected to molecular detection. The rodent brain samples were also used in molecular analysis which is considered the most susceptible part of infection for the parasite and pig blood samples were used targeting the B1 gene at 530bp by nested PCR. Obtained T. gondii DNA was further sent for sequencing. A total, of 127 rodents and 240 pigs were sampled, while the questionnaire survey involved 143 participants who either reported complaints of rodent infestation in their homes or kept pigs. The overall T. gondii infection seroprevalence for rodents and pigs was 1.57% and 26.25%, respectively. Seropositive rodents originated from Kitwiru ward, seropositivity was predominantly associated with Mastomys natalensis, while seropositive results were found across all surveyed wards for pigs. The statistical analysis showed a significant correlation between seropositivity and rodent species (df= 2, χ2=6.2926, p=0.043). However, no significant correlation was found between seropositivity and sex in either rodents or pigs. T. gondii DNA was detected from all two seropositive rodents and two out of the sixty-three seropositive pigs. Sequences from this study formed phylogenetic linkage when compared with other sequences from different animals including humans from other parts of the globe with the highest homology percentage of 99.15%. However, the questionnaire survey showed an inadequate level of awareness of about 30.1%, exposure to cat feces without gloves, keeping cats at their homes, and mishandling of abortion cases in livestock were identified as risk factors for disease transmission in humans in the study area. Detection of antibodies against T. gondii infection in a notable proportion of rodents and pigs, coupled with the subsequent identification of its DNA within both animal species samples, indicates the potential public health implications of these animals in the study area. Moreover, the observed inadequate awareness about toxoplasmosis amplifies the risk of disease transmission among the community. Consequently, it is crucial to implement effective strategies to safeguard the community from this neglected but serious disease.
Diversity and temporal fluctuations in abundance of rodents, shrews and their flea- ectoparasites in an extensive agricultural landscape of Mgeta division, Morogoro region, Tanzania
(Sokoine University of Agriculture, 2024-05) Chonde, Constance Chisala
Rodents and shrews play an important role in a variety of ecosystems including crop farming and the keeping of food animals. Increasing cultivation of crops and livestock keeping in Mgeta division, along the western slopes of Uluguru Mountain, is threatening the survival of rodents and shrews, and consequently, changes in the likelihood of these animals in their disease transmission patterns, which involves also their ectoparasites, particularly fleas, due to changes in their abundance and distribution in the ecosystem. This study was conducted from December 2021 to May 2022, and intended to investigate the diversity and temporal fluctuations in abundance of rodents, shrews and their flea- ectoparasites in Mgeta, an area with extensive agriculture in south- east Tanzania. Three habitats (forest, fallow and cultivated lands), each, were selected and defined as low (1,100 - 1,500 m a.s.l) and high (1,600 - 1,900 m a.s.l) elevations and subsequently sampled for rodents, shrews and their flea-ectoparasites. Removal trapping with baited live Sherman®, Harvahart® and locally made traps was carried out. A total of 192 rodents and 15 shrews were captured, and 199 fleas were collected. Identification of the rodents, shrews and fleas was done up to their species levels. Captured rodents included: Rattus rattus (1.45%), Mastomys natalensis (9.66%), Beamys hindei (1.45%), Lophuromys flavopunctatus (21.74%), Lophuromys kilonzoi (2.42%), Praomys delectorum (40.58%), Grammomys ibeanus (8.7%), Graphiurus murinus (1.45%), Mus minutoides (3.38%), Mus musculus (1.45%) and Dasmys spp (0.48%), whereas, the shrew species included: Crocidura olivieri (3.86%) and Crocidura hirta (3.38%). A Total number of 95 (45.89%) rodents and 6 (2.8%) shrews were infested by Dinopsyllus lypusus, Nosopsyllus fasciatus or Ctenopthalmus calceatus. The mean abundance of fleas presented a significant variation among the host species (F (12, 194) = 11.82, P < 0.001), habitats (F (2, 204) = 9.935, P < 0.001) and along the elevation gradient (F (1, 205) = 10.15, P = 0.02). Similarly, the prevalence varied significantly between the hosts (F (12, 194) = 22.44, P < 0.001) and habitats (F (2, 204) = 4.837, P = 0.009) but not with elevation (F (1, 205) = 0.291, P = 0.59). The mean intensity of flea infestation, on the other hand, varied significantly among the hosts (F (12, 194) = 9.257, P < 0.001) and along the elevation gradient (F (1, 205) = 47.91, P < 0.001), but not habitats (F (2, 204) = 0.75, P = 0.474). Furthermore, while rainfall intensity was strongly associated with mean abundance of fleas (r = 0.054, P < 0.05), neither temperature, elevation, nor humidity were correlated with either mean intensity or prevalence of fleas on the hosts. However, rainfall, temperature, and relative humidity had a significant effect on rodent and shrew abundance (P< 0.05). Given the discovery of D. lypusus, which is a well-known vector of the plague pathogen, Yersinia pestis, and a common ectoparasite of M. natalensis and R. rattus. Effective conservation strategies to preserve the remainder forest patches and community awareness programs regarding the existence of potential plague vectors and mitigation measures in the study area as well as avoidance mechanism should be implemented to ensure the health of the entire ecosystem.
Prevalence of parasites in silvery mole rats in Morogoro region, Tanzania
(Sokoine University of Agriculture, 2024-05) Shija, Debora Elias
The silvery mole rat (Heliophobius argenteocinereus) is a subterranean rodent with a wide distributional range throughout Sub- Saharan Africa. They are herbivores feeding on underground organs of a variety of plants. Despite being used as a source of protein by some local communities in Africa, the rats have been reported to host several parasites. However, the status of the parasites infesting/infecting silvery mole rats in Tanzania has not been well studied. Exploring the ectoparasites and endoparasites species diversity in silvery mole rats opens up a fascinating avenue for understanding the intricate relationships between these underground-dwelling mammals and their parasites. It is intriguing to consider the potential threat for transmission of parasitic zoonoses between humans, livestock, and silvery mole rats due to the notable interactions in the environment. Consequently, the key aim of this study is to acquire crucial information about the ectoparasites and endoparasites in silvery mole rats in the Morogoro region, Tanzania. A survey to establish the status of ectoparasites and endoparasites in silvery mole rats was conducted in Mlali (Mlali, Mkuyuni, Mongwe and Kipera villages) and Mji mkuu wards of Mvomero and Morogoro urban districts in Tanzania, from March to June 2023. Silvery mole rats were collected manually using hand hoes excavation from their burrows in agroecological areas. The captured rats were euthanized using Diethyl Ether, ectoparasites were collected from animal fur, blood samples were collected directly from the heart, and GIT contents were collected by flushing the GIT using physiological saline after opening of the abdominal cavity. During postmortem adult worms found inside the tract and around the pelvic, thoracic, and abdominal cavities were collected and preserved in 70% ethanol. The collected ectoparasites were fixed in a series of alcohols, cleared in xylene, and mounted on microscopic slides. A flotation method was adopted for processing gastrointestinal contents, and the recovered adult helminths were processed by using lactophenol mounting techniques for nematodes and aceto-carmine staining techniques for cestodes. For hemoparasites detection, the blood and impression smears from the kidney, liver, and lungs were prepared and stained with Giemsa stain for microscopic examination. Using taxonomic keys, ectoparasites, hemoparasites, and helminths were identified based on their morphological features. The prevalence of ectoparasites, hemoparasites, and gastrointestinal parasites was computed, and a chi-square test was applied to assess the relationship between parasites and animal body parameters, the association with a p ≤ 0.05 was considered significant. One hundred thirty-seven silvery mole rats were collected, adult females 65% (89/137) were the dominant among the collected rats. A total of 1503 ectoparasites were collected, identified, and revealed to two taxa of mite spp which were Androlaelaps spp 93.15% (1400/1503) and Echinolaelaps spp 6.19% (93/1503), and one taxon of tick the Haemaphysalis spp 0.6% (10/1503) with an overall prevalence of 71.5% (98/137), mite species were the most abundant (94.98%). Two species of blood parasites were detected with an overall prevalence of 29.2% (40/137) and identified as Anaplasma spp 25.5% (35/137) and Babesia spp 16.8% (23/137). Three species of gastrointestinal helminth were detected including taxa of cestode and nematode. A taxon of cestode was identified as Hymenolepis diminuta with an overall prevalence of 20.44% (28/137). A total of 385 adult H. diminuta and 1450 cestode EPG were collected from the gastrointestinal tract. Two species of nematodes; Physaloptera spp and Strongyloides spp were revealed with an overall prevalence of 39.42% (54/137), Physaloptera infection was the most prevalent at 37.22% (51/137) and the only adult nematode recovered among the two nematode species. A significant association was shown between blood parasites and adult silvery mole rats (p = 0.004), and between ticks and babesiosis, tick and anaplasmosis with p of 0.001 and 0.01, respectively. The cestode infection had a significant association with both host age and reproductive category (p< 0.05). Adult silvery mole rats had a lower infection risk than sub-adult rats, with an odds ratio of 0.6 (95% CI 0.24-1.87). Female silvery mole rats were at higher risk of being infected with nematode parasites compared to males, with an odds ratio of 1.6 (95% CI 0.78-3.43). The findings of this study indicate that ectoparasites, hemoparasites, and gastrointestinal helminths are prevalent among silvery mole rats in Morogoro region and might be the source of the infection in humans and livestock. Further studies on the epidemiology of the parasites identified and others that were not found in this study at the molecular level for advanced characterization are recommended to explore their zoonotic potential.
Prevalence and antimicrobial resistance profile of foodborne salmonella enterica and escherichia coli from rodents and shrews in Morogoro municipality, Tanzania
(Sokoine University of Agriculture, 2024-05) Uwanyirigira, Marie Chantal
Rodents and shrews were identified as transmitters and carriers of Salmonella enterica, Escherichia coli (E. coli), and their antimicrobial resistant strains; however, few researchers have examined rodents feces infections. Antimicrobial resistance (AMR) is a pressing issue in the field of global public health, impacting both human and animal health. Small mammals such as rodents and shrews excrements constitute a significant reservoir of zoonotic pathogens, including bacteria resistant to antimicrobials. To date, there is a need for more documented research specifically addressing Escherichia coli (E. coli) and Salmonella enterica strains derived from small mammal feces samples collected in Morogoro Municipality. This study aimed to determine the prevalence and antimicrobial resistance profile of Salmonella enterica and E. coli associated with rodents and shrews in five wards selected in Morogoro Municipality, Tanzania, from March to November 2023. Questionnaires were used to assess risk factors of Salmonella enterica and E. coli associated with house rodents and shrews. This study isolated bacteria extracted from fecal samples of rodents and shrews by using a culture test and identified them with biochemical tests. Molecular tests were used to screen out bacteria-targeted. The isolates bacteria were analyzed for AMR using the disc diffusion method for susceptibilities test to the selected antibiotics. Molecular analysis was used to identify the species of bacteria using 16S rRNA and InvA. Polymerase chain reaction (PCR) was used to find resistance genes in each isolate, including Bla TEM, Bla SHV, Bla CTXM, Sul 1, and Sul 2. A total of 148 small mammals were captured, 145 (98%) were rodents and 3(2%) were shrews. These small mammals were captured from domestic, peri-domestic, and marketplaces. Salmonella enterica was detected in 3/148 (2%), and E. coli was found in 54/148 (36.5%) samples. Most rodents infected by E. coli and Salmonella enterica were Mus species, with 16.2% and 1.3% respectively. Regarding habitat, the high prevalence of E. coli was bserved in open markets, at 16.9%, while Salmonella enterica was high inside households, with 1.3%. Regarding the risk factors associated with house rodents and shrews, 83.7% of respondents found rodents feces in uncooked or cooked food, 30.4% found rodents feces in the water storage, 93.2% found food eaten by rodents, whereby 66.9 % of households used food contaminated with feces or eaten by rodents. Twenty-seven percent (27%) of the respondents were diagnosed with Diarrhea, which may be linked with pathogens from rodents and shrews. The AMR on Amoxicillin was observed in shrews at 100%, in Rattus rattus was 89.5%, and Mus spp was 87.5%, while AMR to Ampicillin on Rattus rattus was 74% and in Mus spp was 62.5%. Salmonella Enterica was more resistant than E. coli for Sulphamethoxazole/Trimethoprim, Ciprofloxacin, and ampicillin. E. coli was more resistant to Amoxicillin than Salmonella Enterica. Concerning the genes linked to E. coli and Salmonella enterica, the results showed that Salmonella Enterica harbored more resistance genes (20%) than E. coli (12%). Two (2) isolates, out of 13 contained Sulphonamide-resistant genes as follows: Sul 1 (n=1) of Salmonella enterica and Sul 2 (n=1) of E. coli, both representing 15.4% of the total resistant gene analyzed in this study. β- lactamases (Bla TEM , Bla SHV, Bla CTXM) were found in 7 isolates (53.8%), with Salmonella enterica harboring more resistance genes than E. coli. The results of this study indicated that the public health significance of pathogens in rodents and shrews from the study area requires further investigation because these animals live close to humans and are also able to move from one place to another, which can increase the transmission of pathogens harbored by them to humans or the environment. Also, this research reveals the presence of resistant Escherichia coli and Salmonella enterica in small mammals, which indicate the potential role of rodents and shrews as a reservoir for AMR E. coli and Salmonella enterica that can be transferred to humans.

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