Articles, Conference and Workshop Papers Collection

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Use of molecular methods to detect shedding of mycobacterium bovis in cattle faeces and milk
(Sokoine University of Agriculture, 2015) MALAKALINGA,JOSEPH
Bovine tuberculosis (BTB) is a chronic bacterial disease caused by Mycobacterium bovis. It affects cattle and occasionally other animals and human. Several techniques exist for detection of BTB in animals. In Tanzania, Single Intradermal Comparative Tuberculin Test (SC1TT) and abattoir meat inspection are the commonly used methods for screening of BTB. This study has used molecular biology method namely; RD4 Real time PCR (RD4 Rt PCR) to detect shedding M. bovis in milk and faecal samples from cattle tested by SCITT and Bovigam test. The study has also determined the detection limit of Immunomagnetic capture (IMC) and Centrifugation methods of M. bovis cells in spiked milk. A total of 63 cattle dairy form LITA farm Morogoro were tested for BTB with SCITT and Bovigam test. Faecal and milk samples-were collected and RJD4 Rt PCR was used to detect M. bovis DNA. BTB prevalence detected by SCITT and Bovigam was 3.1% and 3.1% respectively and BTB prevalence detected by RD4 Rt PCR in milk and faeces was 36.1% and 9.5% respectively. The kappa value between the SCITT and Bovigam was 1 and between shedding of M. bovis in milk and faeces detected using RD4 Rt PCR was 0.07. The detection limit of IMC and centrifugation coupled with Real time PCR ranges from 100 to 1 000 M. bovis cells per 500 pl milk and 10 to 100 M. bovis cells per 500 pl milk sample. High number of cattle was detected by Real time PCR to have BTB compared to SCITT or Bovigam. The confirmation of M. bovis in milk indicates potential root of transmission of M. bovis from cow to calf also to human who consume raw milk. Moreover, confirmation of M. bovis in feces indicates possible contamination of cattle carcasses during slaughter process. The study proposes that in order to improve BTB diagnosis for controlling and management of BTB, both conventional, SCITT or Bovigam and molecular methods in feces and milk need to be deployed in parallel but considering their own merits like cost and repeat access to animals.
Molecular investigation of multiplicity of infections and drug resistance to sulphadoxine-pyrimethamine (sp) in plasmodium falciparum malaria in Mlimba, Tanzania
(Sokoine University of Agriculture, 2004) MBUGI,ERASTO
The study was aimed at molecular investigation of multiplicity of infections and drug resistance to sulphadoxine-pyrimethamine (SP) in Plasmodium falciparum malaria. This molecular epidemiological study involved 141 blood samples from patients aged less than five years from malaria-endemic Mlimba division of Kilombero District, Morogoro, south eastern Tanzania. Blood samples were collected on filter papers (3MM Whatmann) and parasite DNA was extracted by Chelex technique. Molecular analysis on the merozoite surface protein 2 (MSP2), dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) was based on polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) of PCR products (PCR-RFLP). These techniques made it possible to determine the multiplicity of infections and SP resistance-associated point mutations anticipated at sorting out recrudescence from new infections. The commonly reported point mutations occurring at codons 51, 59, 108 and 164 in the DHFR and codons 437, 540 and 581 in the DHPS domains were investigated. The results showed the multiplicity of infection array of single to six infections per patient with an average multiplicity of 2.58 infections per patient. Fifty-one patients possessed single alleles of either allelic families of the MSP2 gene in PCR-RFLP successful samples. Double, triple and multiple infections were detected in 37.7%, 11.9% and 5.9% of patients, respectively. Regarding drug resistance molecular markers, 66.9% carried mutations at codon 108, 62.7% at codon 51 and 48.8% at codon 59 of DHFR domain. Fifty-six (43.7%) of samples carried mutations at codon 437, 39.2% at codon 540 and 0.8% at codon 581 on the DHPS domain. Proportions of mixed variants in the DHFR domain ranged from 0 - 21.5% and 0.8 - 6.3% in the DHPS domain. About 44 (36.4%) of isolatesiii harboured triple mutant DHFR genotypes, whereas quintuple mutation was observed in 24 (19.8%) of isolates. Ten (8.3%) isolates possessed at least double DHFR and double DHPS mutants. This study found a high proportion of SP resistance- associated point mutations in Mlimba two years after deployment of SP as a first-line antimalarial drug in Tanzania. However, the adequate clinical response (81.1%) observed clinically reflects the role of semi-immunity component in the study population. This implies that used molecular markers for monitoring drug resistance, be done simultaneously with studies on confounding factors pertaining to development of resistance against SP in falciparum malaria. The extensive use of antifolates other than SP for treatment of infections other than malaria is a probable candidate for potentiating selection of mutations ascribed to SP resistance. The SP resistance potential detected in this study, caution on its useful therapeutic life as an interim first-line drug against malaria in Tanzania
The role of rodents in the maintenance of the east African tick-borne relapsing fever aetiological agent, Borrelia duttonii
(Sokoine University of Agriculture, 2003) JESSEY,PAX
A total of 250 rodents, 251 adult and nymph ticks and seven human blood samples were collected from Mvumi township in Dodoma region, Tanzania, between November, 2001 and February, 2002, and analysed for the presence of the tick-borne relapsing fever agent (TBRF), Borrelia duttonii. Cultures of the spirochetes were made in Barbour-Stoenner-Kellys (BSK-II) medium, and molecular characterization of the spirochetes was done by polymerase chain reaction (PCR). Spirochete cultures were successfully grown from two out of the seven human blood samples. No spirochetes grew in either of the cultures of the rodent blood or the tick haemolymph and crushed tick samples. These samples were negative for spirochetes by staining and direct microscopy. PCR detected Borrelia DNA from two of the seven human blood samples, and from one of either rodent (Rat t us rattus), and tick samples. This is the first study on the possibility of rodents playing a role in the transmission of Borrelia spp in Tanzania. The detection of Borrelia DNA in rodents originating from this TBRF endemic area suggests the possibility of rodents playing a role in the maintenance of the TBRF agent, B. duttonii. Since it is generally accepted that only humans are the reservoirs of B. duttonii, this study calls for further investigation to determine the importance of commensal rodents and other mammals in the epidemiology of relapsing fever in Tanzania.
The distribution of contagious caprine pleuropneumonia in selected areas of Tanzania
(Sokoine University of Agriculture, 2005) KIMARYO,STEPHEN JAMES
A study was carried out to establish the distribution of Contagious Caprine Pleuropneumonia (CCPP) in Iringa, Mpwapwa and Kilosa districts, Tanzania. Information on the history of outbreaks was collected and clinical examination of goats with respiratory disease was conducted. Some typical cases were sacrificed for gross pathological evaluation. A total of 1247 serum samples (including 8 from sheep) were collected for serological analysis using the latex agglutination test (LAT). Nasal swab (57), lung (13), bronchial lymph node (13) and pleural fluid (6) samples were collected for microbiological culture and isolation of Mycoplasma capricoluni subsp. capripneiunoniae (M. capripneiunoniae') using a Ilayflick-based medium enriched with sodium pyruvate and containing 25% serum (H25P medium). Some samples were also cultured on a commercial freeze-dried CCPP diagnostic medium. Mycoplasma isolates on H25P medium were identified using the disc growth inhibition test while those on CCPP diagnostic medium were identified on the basis of their growth and colonial characteristics. All the sick and sacrificed goats showed clinical signs and post mortem features that were highly suggestive of CCPP. In Iringa district, out of the 250 goat sera from Mahenge division, 126 (approx. 50%) were positive for antibodies against M. capripneiunoniae, whereas of the 250 sera from Idodi division, 115 (46%) were seropositive. In Mpwapwa district, out of 301 analysed goat sera from Kibakwe division, 152 (approx. 50%) were seropositive compared to 47 (approx. 47%) of the 99 sera from Rudi division. Out of eight sheep sera, which were collected from Mpwapwa district, three (38%) had antibodies against M. capripneiunoniae. In Gairo division (Kilosa district), 339 goat sera were screened and 253 (approx. 75%) were seropositive. M. capripneiunoniaeiii was isolated from specimens from all the study districts. The results of this study indicate that the suspected outbreaks in the study areas were true CCPP. This provides additional information on the distribution of the disease in the country. The observation of characteristic colonics of M. capripneumoniae on the CCPP diagnostic medium demonstrates the latter’s potential in the field investigations of suspected CCPP outbreaks. The demonstration of M. capripneumoniae antibodies in sheep probably suggests that sheep are also susceptible to infection with the mycoplasma and may play a role in the epidemiology of CCPP. However, this aspect needs further investigation especially in pastoral and agro-pastoral systems where goats and sheep are often reared together.
Studies on canine transmissible venereal tumour of dogs in Mvomero and Morogoro municipality, Tanzania
(Tanzania Veterinary Association, 2018) Ishengoma, V. L.; Ndossi, D. G.; Nonga, H. E.
Canine transmissible venereal tumour (CTVT) is a contagious tumour that is naturally transmitted between dogs by the allogeneic transfer of living tumour cells during coitus. A cross-sectional study was conducted in Mvomero and Morogoro Municipality between September and November 2017 in order to determine the prevalence of CTVT and level of people’s awareness on the disease. The knowledge and interventions in reference to CTVT were evaluated using a structured questionnaire, whereas the status of the disease in animals was investigated through clinical examination. A total of 200 respondents were interviewed and 300 dogs were examined. Results on questionnaire showed that, most of the respondents had their dogs managed freely as stray dogs. Majority of the dog owners had one to five dogs and with no controlled breeding. It was further established that majority of the respondents knew CTVT as a disease of bleeding in dogs and had seen dogs affected by the disease suggesting that the disease is common in the study areas. Nevertheless, the real cause and treatment was not clear to most of the dog keepers. Based on clinical examination of dogs, the prevalence of CTVT in dogs was 12%, with Mvomero district having more cases of CTVT, 23 (15.4%) than Morogoro Municipality which had 13 (8.6%). In Mvomero district, Dakawa ward had the highest number of CTVT cases 12 (8.1%). Furthermore, it was found that male dogs were more affected by CTVT (15.3%) as compared to female dogs (8.7%). This study shows that magnitude of CTVT is high in the study area and insufficient knowledge and misconception on clinical presentation, spread, and treatments of the disease prevail. Therefore deliberate measures aimed at minimizing the problem need to be taken.
Effect of pyriproxyfen and ivermectin on survival and reproductive perfomance of plague flea vectors, xenopsylla cheopis
(Sokoine University of Agriculture, 2023-11) Mwakalinga, Nicolaus Anania
EXTENDED ABSTRACT One of the primary carriers of plague in many tropical and subtropical regions of the world is Xenopsylla Cheopis. Targeting flea vectors by sprinkling or dusting homes and surroundings with chemical insecticides is the primary method for controlling plague. However, the likelihood of insecticide resistance has increased because to the prolonged use and excessive reliance on chemical insecticides. Ivermectin and pyriproxyfen, which target both endoparasites and ectoparasites, will limit their actions and reduce their susceptibility to resistance. These substances have however not tested against plague fleas. The objectives of this study were to evaluate the effects of pyriproxyfen and ivermectin on reproduction and survival, as well as the viability of incorporating them into the current management methods. Two experimental designs were used; the first exposure to pyriproxyfen was investigated for its efficacy against adult, fecundity, and larval stages of the oriental rat flea. The contact bioassays against both the larval and adult stages of fleas conducted through series of laboratory experiments. In adult fleas, treatment and controls groups were tested in four replicates while larvae were six replicates. Exposure time of pyriproxyfen for adult fleas were 30 minutes and none for larvae Twelve rats were used in total for the second exposure method of the ivermectin and pyriproxyfen . Four rats were given 0.2 ml of ivermectin, four were given 0.3 g of pyriproxyfen powder, and four were left untreated. The adult fleas were exposed for 12 hours, and 10 days of observation followed. The survival curve of adult fleas was produced after data analysis using the R software. Additionally, the least square method was used to calculate the impact of pyriproxyfen and ivermectin on adult mortality. The survival rate of adult Xenopysylla cheopis fleas in a treatment group shown to be 100% at day 0. As time passed, there was a decreasing chance that the treated group would survive, and by day six, every flea in the treated group had died (P=0.0313). In comparison to the control group, the treatment group significantly produced less eggs (<0.0001). In the treatment group of flea larvae, ii 90% of the larvae died by day eight, and by day 20 of monitoring and observation, there were no cocooned flea larvae. 98% of the larvae in a control group survived and 60% of them formed cocoons. According to the research, adult fleas, egg viability, egg laying, and larval growth are all affected when 2g of pyriproxyfen mixed with sand and dried cattle blood powder is directly applied to them. Pyriproxyfen alone was considerably less toxic to adult fleas during a period of 24 hours, and mortalities began from day 2 and increased. However, similar hormone with other exposure methods in conjunction with ivermectin in action have shown that this is not the case. Pyriproxyfen was very effective in day four using the least square method, with an LS mean of 3.75 and a 0% egg-laying rate. Maximum mortalities were achieved at day five with an LS mean of 4.5 and a P-value of (0.0001), and 5% less eggs were deposited by adult fleas that were exposed to ivermectin. The combination of pyriproxyfen and ivermectin was effective against adult fleas, with the largest mortalities occurring on days three and four with LS Means of 4.75 and 5, respectively, and no eggs being deposited during the course of the monitoring period of ten days. This combination of pyriproxyfen and ivermectin may be utilized to better control the plague in endemic areas and as flea vector control agents.
Respiratory syndrome in relation to occupational pesticide exposure among farmworkers: A case study of Kilimanjaro and Arusha regions, Northern Tanzania
(Sokoine University of Agriculture, 2023-09) Owisso Rose Donati
In developing countries, the use of pesticides has been increasing due to an increase in new pests and diseases. This has resulted in the use of highly hazardous pesticides (HHPs) with the potential of causing health risks including respiratory syndromes and sometimes deaths to humans. The World Health Organization (WHO) estimated three million cases of acute pesticide poisoning and 220,000 deaths annually worldwide. Despite the significance of pesticide exposure to pesticides, studies on long health effects associated with pesticide exposure among the working population are limited in low- and middle-income countries (LMICs). A previous study conducted among farmworkers in Arumeru District of Tanzania revealed health problems resulting from Acute Pesticide Poisoning (APP) were related to other diseases such as malaria and pneumonia that lead to misdiagnosis and underreporting of the health challenges resulting from exposure to occupational pesticides. Thus, the current study aimed at investigating the association between occupational exposure to pesticides and respiratory syndromes among farmworkers in Arumeru and Moshi Districts in Arusha and Kilimanjaro regions. A cross-sectional study involving both semi- structured questionnaire and Key informative interview data collection methods was used to assess the respiratory health challenges experienced by farmworkers when applying either synthesized pesticides or organic inputs to either coffee or flowers farm. Key Informant Interviews (KIIs) was used to gain a deeper understanding of the farmworkers’ awareness of occupational exposure to pesticides and organic inputs in relation to the respiratory syndrome. The study participants included both male and female farmworkers of between 18 and 48 years of age working in flower and coffee plantation farms in Arumeru and Moshi Districts. 194 non-organic and 195 organic farmers who were directly engaged in agricultural activities were randomly selected from their farms to participate in the study. Among 389 study participants, 24 farmworkers were purposively selected to participate in the key informative interview (KII). Supporting staff such as Human Resource Officers found in the study farms but not engaged directly in agricultural activities were excluded from this study. adj. OR (95% CI)4.58(1.68, 12.54), 4.74 (1.83, 12.29) and 6.30 (1.29,30.72] . In the KII, it was reported that pesticide mixers and sprayers were using person protective equipment, taking baths and changing clothes after farm work while other farmworkers such as flower pruners, flower graders and coffee pickers were not using protective equipment. The visited coffee organic farm was not equipped with sanitary facilities and farmworkers were not protecting themselves from direct contact with the organic inputs. The results in the quantitative study indicate that pesticide mixers and sprayers in flower farms were significantly associated with cough, rhinitis and wheezing, [ respectively. Moreover, there was a decreasing risk of cough and rhinitis for flower farmworkers taking baths after work, [adj. OR (95% CI) 0.33 (0.16, 0.68) and 0.44(0.26, 0.75)] results showed the association between respiratory syndrome and occupational exposure to pesticides among to chemical pesticides. There was an inconclusive result on Furthermore, non-organic farmworkers who were at high risk of exposure the association between respiratory syndrome and organic inputs given that other causes such as allergies were not investigated.
Hatching of artemia franciscana and it’s performance in fertilized ponds
(Sokoine University of Agriculture, 2024-05) Jacob, Augustino Tegemea
This study was conducted to assess the general performance of Artemia franciscana from saltworks in Tanga, Tanzania. The study aimed to determine Artemia cysts’ biometry and hatching efficiency, and effect of pond fertilization on growth performance and nutritional composition of Artemia. For the study on biometry and hatching efficiency, Artemia cysts were collected from salt farms in Tanga, Tanzania, using a 100-150 mesh net. Then the cysts were processed and packed in airtight containers. In the laboratory, the diameter of each cyst was measured from a sub sample of 200 cysts and another sub-samples were incubated in beakers at 28 °C, 35 ppt, and a pH of 8. After 24 hours, newly hatched nauplii were moved in triplicate to the culturing tanks, where they were cultured for 15 days while being fed microalgae (Nannochloropsis oculate). As a reference, the Vinh Chau Artemia cyst strain (from Vietnam) was used as control. The findings showed that Artemia cyst from Tanga had a higher value of capsulated cyst diameter (213.4μm) and chorion thickness (9.7μm) compared to Vinh Chau Artemia cysts (208.3 μm; 8.3 μm) respectively. Also, a higher hatching percentage and efficiency was observed in Vinh Chau Artemia cyst compared to Tanga (p < 0.05). However a higher growth performance and survival percentage (74.56%) were observed in Tanga Artemia strain compared to Vinh Chau Artemia strain (53.85%) which is very promising. Hence, Tanga Artemia strain showed good quality hence its prospects to production in pond. However, the study on the effects of pond fertilization, examined the growth performance and nutritional composition of Artemia. At 28 °C, 35 ppt, and a pH of 8, six buckets each holding 20 liters of water were used to hatch a total of 30g cysts. The newly hatched nauplii were then inoculated in triplicates into the fertilized and non-fertilized ponds, where they were cultured for 28 days at a density of 100 nauplii/litre. The results on Artemia’s growth performance and nutritional composition were significantly greater in fertilized ponds (p<0.05). Phytoplankton communities were also more abundant in fertilized ponds compared to non-fertilized ponds. All the environmental parameters monitored were within the recommended range for example the mean salinity was above 70ppt. The findings from this study suggested that pond fertilization is of great importance for quality and optimal production of Artemia in ponds. The results of this study lead to the conclusion that Tanga cysts exhibit good biometric characteristics as well as good growth performance when exposed to pond fertilization. As a result, we recommend further research in order to enhance more traits of the local Artemia breed in pond production.
Estimating risk of introduction of ebola virus disease from the democratic republic of Congo to Tanzania: a qualitative assessment
(MDPI, 2022-02-11) Rugarabamu Sima; Mwanyika Gaspary O.; Misinzo Gerald; Mboera Leonard E. G.; George Janeth; Mbanzulu Kennedy M.
Between April 2018 and November 2020, the Democratic Republic of Congo (DRC) experi- enced its 11th Ebola virus disease (EVD) outbreak. Tanzania’s cross-border interactions with DRC through regular visitors, traders, and refugees are of concern, given the potential for further spread to neighboring countries. This study aimed to estimate the risk of introducing EVD to Tanzania from DRC. National data for flights, boats, and car transport schedules from DRC to Tanzania covering the period of May 2018 to June 2019 were analyzed to describe population movement via land, port, and air travel and coupled with available surveillance data to model the risk of EVD entry. The land border crossing was considered the most frequently used means of travel and the most likely pathway of introducing EVD from DRC to Tanzania. High probabilities of introducing EVD from DRC to Tanzania through the assessed pathways were associated with the viability of the pathogen and low detection capacity at the ports of entry. This study provides important information regarding the elements contributing to the risk associated with the introduction of EBV in Tanzania. It also indicates that infected humans arriving via land are the most likely pathway of EBV entry, and therefore, mitigation strategies including land border surveillance should be strengthened.
Forty-two years of responding to Ebola virus outbreaks in Sub-Saharan Africa: a review
(BMJ Global Health, 2020-01-27) Rugarabamu Sima; Mboera Leonard E. G.; Mbanzulu Kennedy M.; Rweyemamu Mark; Lutwama Julius; Paweska Janusz; Misinzo Gerald
Introduction Ebola virus disease (EVD) is one of the deadliest haemorrhagic fevers affecting humans and non- human primates. Thirty-four outbreaks have been reported in Africa since it was first recognised in 1976. This review analysed 42 years of EVD outbreaks and identified various challenges and opportunities for its control and prevention in Sub-Saharan Africa. Methods A literature search of relevant articles on EVD was done in PubMed, Web of Science and Google Scholar electronic databases. Articles published from 1976 to 2019 were reviewed to document reports of EVD outbreaks in Sub-Saharan Africa. Data extraction focused on the year of outbreak, geographical spread, virus strain involved, number of cases and deaths, case fatality, and outbreak management. Analyses of trends in case fatality were performed by calculating ORs between times. Results In the past four decades, a total of 34 EVD outbreaks affecting 34 356 cases and causing 14 823 deaths were reported in 11 countries in Sub-Saharan Africa. The overall case fatality rate (95% CI) was 66% (62 to 71) and did not change substantially over time (OR in 2019 vs 1976=1.6 (95% CI 1.5 to 1.8), p<0.001). The results of this review indicate that challenges to control EVD outbreaks are related to epidemiological, sociocultural and health system factors. Conclusions Sub-Saharan Africa continues to face considerable challenges in EVD control, whereby there are no significant changes in case fatality rates observed during the past four decades. Socioeconomic and cultural processes need to be critically considered to shape the community behaviours that lead to exposure to EVD outbreaks. Areas that need to be addressed to prevent future EVD outbreaks include a broad-based, one-health approach, effective communication, social mobilisation, and strengthening of the health systems.
Seroprevalence and associated risk factors of selected zoonotic viral hemorrhagic fevers in Tanzania
(ELSEVIER, 2021) Rugarabamu Sima; Rumisha Susan F.; Mwanyika Gaspary O.; Sindato Calvin; Lim Hee‐Young; Misinzo Gerald; Mboera Leonard E. G.
Objective: To determine the seroprevalence of selected zoonotic viral hemorrhagic fevers (VHFs) and their associated risk factors in Tanzania. Methods: Blood samples were collected from consenting outpatients and community members in eight districts selected from five ecological zones of Tanzania. Serum was harvested and tested for the presence of immunoglobulin G (IgG) and M (IgM) antibodies against Crimean-Congo hemorrhagic fever (CCHF), Ebola virus disease (EVD), Marburg virus disease (MVD), Rift Valley fever (RVF), and yellow fever (YF). Results: The presence of IgM and IgG antibodies against CCHF, EVD, MVD, RVF, and YF was detected in 64 of 500 samples (12.8%). The prevalences of IgM and IgG antibodies to CCHF, EVD, MVD, RFV, and YF were 2.0%, 3.4%, 1.2%, 4.8%, and 1.4%, respectively. Contact with wild animals (OR = 1.2, CI = 1.3–1.6) and keeping goats (OR = 1.3, CI = 1.5–1.9) were significantly associated with RVF, while contact with bats (OR = 1.2, CI = 1.1–1.5) was associated with MVD. Conclusion: The findings of this study provide evidence of exposure to CCHF, EVD, MVD, RVF, and YF in Tanzania. Since most of these VHFs occurred without apparent clinical forms of the disease, these findings call for the need to strengthen the surveillance system and management of febrile illnesses in Tanzania.
Viral haemorrhagic fevers and malaria co‐infections among febrile patients seeking health care in Tanzania
(BMC, 2022) Rugarabamu Sima; Rumisha Susan F.; Mwanyika Gaspary O.; Sindato Calvin; Lim Hee‐Young; Misinzo Gerald; Mboera Leonard E. G.
Background: In recent years there have been reports of viral haemorrhagic fever (VHF) epidemics in sub-Saharan Africa where malaria is endemic. VHF and malaria have overlapping clinical presentations making differential diagno‐ sis a challenge. The objective of this study was to determine the prevalence of selected zoonotic VHFs and malaria co-infections among febrile patients seeking health care in Tanzania. Methods: This facility-based cross-sectional study was carried out between June and November 2018 in Buhigwe, Kalambo, Kyela, Kilindi, Kinondoni, Kondoa, Mvomero, and Ukerewe districts in Tanzania. The study involved febrile patients seeking health care from primary healthcare facilities. Blood samples were collected and tested for infections due to malaria, Crimean-Congo haemorrhagic fever (CCHF), Ebola virus disease (EVD), Marburg virus disease (MVD), Rift Valley fever (RVF) and yellow fever (YF). Malaria infections were tested using rapid diagnostics tests while exposure to VHFs was determined by screening for immunoglobulin M antibodies using commercial enzyme-linked immuno‐ sorbent assays. The Chi-square test was used to compare the proportions. Results: A total of 308 participants (mean age = 35 ± 19 years) were involved in the study. Of these, 54 (17.5%) had malaria infection and 15 (4.8%) were positive for IgM antibodies against VHFs (RVF = 8; CCHF = 2; EBV = 3; MBV = 1; YF = 1). Six (1.9%) individuals had both VHF (RVF = 2; CCHF = 1; EVD = 2; MVD = 1) and malaria infections. The highest co-infection prevalence (0.6%) was observed among individuals aged 46‒60 years (P < 0.05). District was significantly associated with co-infection (P < 0.05) with the highest prevalence recorded in Buhigwe (1.2%) followed by Kinondoni (0.9%) districts. Headache (100%) and muscle, bone, back and joint pains (83.3%) were the most significant complaints among those infected with both VHFs and malaria (P = 0.001). Conclusions: Co-infections of VHF and malaria are prevalent in Tanzania and affect more the older than the younger population. Since the overlapping symptoms in co-infected individuals may challenge accurate diagnosis, adequate laboratory diagnosis should be emphasized in the management of febrile illnesses.
Trypanosome non-specific antibody responses during trypanosoma congolense infection of cattle
(Sokoine University of Agriculture, 1998) Buza Joram Josephat
EXPERIMENT ONE Trypanosome infections of cattle are characterized by concomitant increase in serum IgM, development of antibodies reacting with non-trypanosome antigens and an increase in the proportion of CD5+ B cells in peripheral blood and spleen. It is not known whether the three events are related. In mice and humans, CD5+ B cells have been shown to predominantly produce IgM antibodies that are polyreactive in nature. This experiment was initiated first to confirm whether trypanosome non-specific antibodies develop during the course of Trypanosoma congolense infections of susceptible Boran or resistant N’Dama cattle. In addition, to investigate whether a different trypanosome species, Trypanosoma vivax, can also induce these antibodies. Secondly, to investigate whether the CD5+ B cells, which increase during trypanosome infections of cattle, are the source of the trypanosome non-specific antibodies observed. Experimental infections were initiated Trypanosoma congolense by tsetsefly bite in 13 susceptible Boran and 6 resistant N’Dama cattle. A separate group of 4 Boran cattle was also infected with a different trypanosome species T. vivax. Serum samples were collected from infected cattle at different time points and tested in ELISA for trypanosome-specific and trypanosome non-specific antibodies. Seven Boran cattle from the T. congolense-infected group were killed between 31-51 after iii infection and mononuclear cells prepared from spleen tissue. The cells were double-stained for CD5 using monoclonal antibody IL-A67 and surface immunoglobulins using monoclonal antibody IL-A58. Separate populations of CD5+ and CD5‘ B cells were obtained by sorting using a flow-cytometer. Equal numbers of CD5+ and CD5‘ B cells were tested in the Silver Immunogold (SIG) blot assay for enumeration of number of cells secreting IgM, IgG and antibodies reacting with non-trypanosome antigens B-galactosidase, ovalbumin and lysozyme. ELISA tests on sera from both Boran and N’Dama cattle infected with Trypanosoma congolense revealed an increase in antibodies which react with a number of non-trypanosome antigens such as B-galactosidase, ferritin and cytochrome, but less or no reactivity was found for antigens such as ssDNA and TNP. A similar development of trypanosome non-specific antibodies reacting with B-galactosidase was found in T. vivax infections of Boran cattle. The trypanosome non-specific antibodies were exclusively IgM, while the trypanosome-specific antibodies were both IgM and IgG. Results from the SIG blot assay revealed that numbers of IgM- and IgG-secreting cells were not different between CD5+ and CD5’ populations (P>0.05). However, significantly more cells in the CD5+ population secreted antibodies reacting with non-trypanosome antigens than in the CD5' population (p<0.05). iv It is concluded from these studies that trypanosome non-specific antibodies develop during trypanosome infections of both in Boran and N’Dama cattle, they can be induced by different trypanosome species, are exclusively IgM and mainly secreted by the CD5+ B cells. EXPERIMENT TWO In the first experiment, IgM antibodies reacting with a number of unrelated non trypanosome antigens were detected in serum of trypanosome infected cattle. These antibodies were mainly secreted by the CD5+ B cells. However, the specificity of these antibodies is not known. Two alternative hypotheses have been put forward to explain the reactivity to unrelated antigens observed in serum of trypanosome infected cattle. The first one ascribes reactivity to unrelated antigens due to presence of different antibody clones, each one possessing different specifity as observed in cases of polyclonal activation. The second one attribute reactivity to unrelated antigens due to presence of antibody molecules, each one capable of binding more than one unrelated antigens, such as the polyreactive antibodies secreted by murine and human CD5+ B cells. This experiment was initiated to investigate whether the trypanosome non-specific antibodies are polyclonal or polyreactive. A pool of serum was made from samples of 6 Boran cattle on 30 days after infection, when trypanosome non-specific antibody levels were highest. The serum V pool was passed through immunoaffmity colums conjugated with either trypanosome antigens or non-trypanosome antigen B-galactosidase. Antibody fractions that bound to the column and those which did not bind were collected and tested in ELISA for their reactivity to trypanosome and non-trypanosome antigens. The IgM fraction purified on B-galactosidase reacted with B-galactosidase, cytochrome, ferritin and the trypanosome lysate. Similar results were obtained for IgM fraction purified on a trypanosome lysate column. The IgM fraction that exhibited reactivity to different antigens was present in both pre-and post-infection sera. In contrast, the IgG fraction purified on trypanosome lysate column reacted only with trypanosome lysate but not with the non-trypanosome antigens. The trypanosome-specific IgG fraction was only found in post-infection sera. These results conclude that trypanosome non-specific IgM antibodies are polyreactive. Their presence in pre-infection sera indicates that the infection does not specifically induce them, but helps to amplify their production. In contrast, trypanosome-specific IgG antibodies are monoreactive and specifically induced by trypanosome infection. EXPERIMENT THREE Trypanosome infections in cattle induce production of both trypanosome-specific and the trypanosome non-specific antibodies. It is known that specific antibodies vi that are directed at the exposed determinants of the variable surface glycoprotein coat play a role of destruction of trypanosomes and eventual elimination of infection. However, the significance of specific antibodies, which recognize various antigens released after the destruction of trypanosomes, and the trypanosome non-specific antibodies are not known. Some workers suggested that antibodies recognizing products of lysed trypanosomes contribute to immunopathological processes such as development of anaemia. However, others suggested that some of these antibodies, such as those binding to trypanosome enzyme cystein protease may play a protective role to the host by neutralizing the enzymatic function of the enzyme. The polyreactive trypanosome non-specific antibodies may potentially bind to host or trypanosome antigens; and both pathogenic and protective consequences are possible. It is therefore, important to study regulation of antibody responses which takes place during trypanosome infections in cattle. Information obtained may help in designing means by which protective antibody responses can be selectively upregulated at the expense of pathogenetic responses. T lymphocytes play an important regulatory role on antibody responses. CD4+ T cells provide helper function to antibody production by B cells during T-cell dependent antibody responses. CD8+ T cells sometimes suppress antibody production. The role played by these two T cell subsets on antibody responses during trypanosome infections of cattle is not known. The aim of this experiment was to investigate the role played by CD4+ or CD8+ on antibody response during T. congolense infection of Boran cattle. vii Cattle were depleted of CD4+ or CD8+-T cells subpopulations by intravenous injection of specific monoclonal antibodies IL-A11 or IL-A105 respectively, before infection. The levels of the two cell subsets in peripheral blood were monitored by flow-cytometric analyses. Serum samples collected at various time points were tested in ELISA for determination of levels of trypanosome-specific and trypanosome non-specific antibodies. Flow-cytometric analyses of peripheral blood mononuclear cells revealed a complete depletion of these T cells subpopulations over a period of two weeks. Serum samples collected at various time points were tested in ELISA assay for specific antibodies reacting with whole lysate of trypanosomes, non-specific antibodies reacting with a non-trypanosome antigen B-galactosidase, and total IgM. Trypanosome-specific antibodies were detected in both IgM and IgG isotypes. In contrast, non-specific antibodies reacting with B-galactosidase were exclusively IgM. Depletion of CD4+-T cells significantly reduced levels of specific, non specific and total IgM (p<0.05) while depletion of CD8+-T cells no effect on these antibody types (p>0.05). These results show that CD4+-T cells play a crucial role in production of trypanosome-specific as well as the trypanosome non-specific antibody responses to viii T. congolense infection in susceptible Boran cattle. CD8 T cells have no effect on antibody responses to trypanosome infections in cattle.
Respiratory mycoplasmoses of cattle and goats with special reference to molecular epidemiology of contagious bovine pleuropneumonia in Tanzania.
(Sokoine University of Agriculture, 2010) Kusiluka Lughano Jeremy Moses
The objective of this PhD study was to elucidate the mycoplasma flora in respiratory tract diseases of cattle and goats and to determine the genetic diversity among them. In a study of pneumonic lungs of Danish cattle, Mycoplasma dispar, M. bovis, M. bovirhinis, M. bovigenitalium and Ureaplasma spp. were the species encountered, predominantly occurring as mixed infections. There was a notable increase in prevalence ofM. bovis, thus calling for special attention upon this mycoplasma. Mycoplasmas belonging to the Mycoplasma mycoides cluster were not encountered in the examined lungs, suggesting that the Danish cattle population is still free from this group of mycoplasmas and that, it is not under special threat from contagious bovine pleuropneumonia (CBPP) if the Danish surveillance system for infectious diseases remains in place. A study of the mycoplasma flora in the respiratory tract of indigenous cattle in selected regions of Tanzania revealed that Mycoplasma mycoides subsp. mycoides, Small Colony type (M. mycoides SC) was the predominant species affecting the animals, and thereby confirming that CBPP is the major respiratory mycoplasmosis of cattle in the study areas. A very low prevalence of M. arginini was recorded in cattle. Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae), M. mycoides SC, M. ovipneumoniae and M. arginini were demonstrated in the respiratory tract specimens of goats originating from different regions of Tanzania. The isolation of M. capripneumoniae during outbreaks of caprine pleuropneumonia in the Coast and Morogoro regions confirmed the presence of contagious caprine pleuropneumonia (CCPP) in these regions. The demonstration of M. mycoides SC in goats with severe pleuropneumonia in the two regions suggests that this mycoplasma may be involved in the pathogenesis of the syndrome, and that goats may play a 17 significant role in the epidemiology of CBPP if cross-transmission of the mycoplasma from cattle and goats and vice versa, does efficiently occur. Amplified fragment length polymorphism (AFLP) fingerprinting of 42 M. bovis strains isolated from Danish cattle from 1981 to 1998 revealed a remarkable homogeneity among them. An epidemiological link between two separate outbreaks of M. Aov/'s-induced mastitis was demonstrated. The association between the first three strains ofAY. bovis isolated in 1981 and those isolated from various disease syndromes in different parts of the country in subsequent years was evidenced by the strong genomic similarity between them. AFLP and pulsed-field gel electrophoresis (PFGE) showed that genomic heterogeneity was more evident among M bovis strains isolated after 1991, probably indicating different origins from those isolated before. The AFLP and PFGE profiles of M. bovis type strain (PG45T) were different from those of the field strains. AFLP and PFGE analysis of 56 field strains of M mycoides SC isolated from cattle in six regions of Tanzania revealed a strong genomic homogeneity among them, which was highly suggestive of a common epidemiological source. This finding supports the idea that nearly all CBPP outbreaks in Tanzania since 1990 are due to spread of one particular epidemic clone of M mycoides SC, and it implies that it would have been possible and cheap to prevent the spread of the disease if appropriate control measures were instituted to contain the initial outbreaks. Strains from Tanzania, Kenya, Botswana and Portugal displayed different genomic profiles, reflecting diversity in their epidemiological origins. In addition, the genomic difference between the Portuguese strain and those from Tanzania, Kenya and Botswana affirmed the separate clustering of the African and European strains of M 18 mycoides SC. The type- (PG1T) and vaccine- (T1.SR49) strains showed indistinguishable AFLP profiles but exhibited different PFGE profiles, which were also different from those of the field strains. The genomic difference between the vaccine- and the field strains probably indicates that a genetic drift has occurred in the field strains, enabling them to avert the protective effects of the vaccine. Hence, the poor efficacy of the vaccine reported in eastern and southern Africa. A strong genomic homogeneity was demonstrated among strains of M. capripneumoniae isolated from outbreaks of CCPP in Tanzania when analysed by AFLP and PFGE, suggesting a common epidemiological source. Genomic homogeneity was also evident among Tanzanian-, Kenyan- and Ugandan strains of M. capripneumoniae, supposing that cross- border transmission of CCPP between these countries was possible. However, subtle differences were also discernible among some Tanzanian and Kenyan strains of M capripneumoniae, probably indicating different evolutionary lineages or epidemiological origins of the strains. The AFLP profile of the type strain ofM capripneumoniae (F38T) was different from those of the field strains. PFGE analysis did not unveil genomic differences among the strains of M. capripneumoniae analysed. This may be due to the inherent strong homogeneity among the strains, but it may also be indicative of the limited discriminatory power of the protocol used for this mycoplasma, and therefore, suggesting further evaluation of the protocol using different restriction enzyme combinations and electrophoresis parameters in order to increase its discriminatory power. Strains of M. mycoides SC isolated from goats with respiratory tract disease including cases of severe fibrinous pleuropneumonia in three regions of Tanzania exhibited indistinguishable 19 AFLP and PFGE profiles, except for one strain which differed from the rest at only position. The AFLP and PFGE profiles ofM. mycoides SC from goats were indistinguishable from those isolated from CBPP-affected cattle in the same regions, suggesting a probable cross transmission of the mycoplasma between the two animal species especially because, in most parts ofthe country, cattle and goats are reared together. In conclusion, this work has demonstrated that mycoplasmas play a significant role in the aetiology of respiratory tract diseases of cattle and goats, thus emphasizing the need to control them. Furthermore, a strong intraspecies homogeneity has been demonstrated among strains of M. bovis, M. mycoides SC and M. capripneumoniae isolated from diseased cattle and goats, which is strongly indicative of close epidemiological relatedness, and most likely common origins of the strains. This implies that it would have been possible to prevent the spread of these infections if effective surveillance and control programmes were in place. Thus, a review of the effectiveness of the existing disease surveillance systems is recommended. Moreover, the study has demonstrated that AFLP and PFGE can be used as additional tools in molecular epidemiological studies of mycoplasma infections in cattle and goats. However, because the methods demonstrated variable levels of discrimination among strains of the mycoplasma species analysed, further studies are recommended to improve their discriminatory power.
Antimicrobial usage in cattle and poultry production in Dar es Salaam, Tanzania: pattern and quantity
(BMC Veterinary Research, 2022) Azabo Rogers; Mshana Stephen; Matee Mecky; Kimera Sharadhuli I.
Background: Antimicrobials are extensively used in cattle and poultry production in Tanzania. However, there is dearth of information on its quantitative use. A questionnaire-based cross-sectional study was conducted from August to September 2019 in randomly selected poultry and small-scale dairy farms, in three districts of Dar es Salaam City eastern, Tanzania, to assess the practice and quantify antimicrobial use. Descriptive and statistical analyses were performed at a confidence interval of 95%. The ratio of Used Daily Dose (UDD) and Defined Daily Dose (DDD) were used to determine whether the antimicrobial was overdosed or under dosed. Results: A total of 51 poultry and 65 small-scale dairy farms were involved in the study. The route of antimicro- bial administration was 98% orally via drinking water and 2% in feeds for poultry and for small-scale dairy farms, all through parenteral route. Seventeen types of antimicrobials comprising seven classes were recorded in poultry farms while nine belonging to six classes in the small dairy farms. Majority of the farms (poultry, 87.7% and small scale dairy, 84.3%) used antimicrobials for therapeutic purposes. About 41% of the poultry and one third (34%) of the dairy farm- ers’ were not compliant to the drug withdrawal periods. Beta-lactams, fluoroquinolones, sulphonamides, tetracyclines and macrolides were the commonly used antimicrobials on these farms. In the poultry farms both those with records and those which relied on recall, antimicrobials were overdosed whereas in the small dairy farms, sulfadimidine, oxytetracycline and neomycin were within the appropriate dosing range (0.8–1.2). The majority (58.6%) of farmers had adequate level of practices (favorable) regarding antimicrobial use in cattle and poultry production. This was associ- ated with the age and level of education of the cattle and poultry farmers. Conclusion: The study revealed a widespread misuse of antimicrobials of different types and classes in both poultry and small-scale dairy farming in Dar es Salaam, Tanzania. This result gives insight into the antimicrobial use practices and its quantification. The information obtained can guide and promote prudent use of antimicrobials among the farmers by developing mitigate strategies that reduce antimicrobial resistance risk potentials.
Taenia saginata cysticercosis in cattle in Tanzania
(Sokoine University of Agriculture, 1993) Maeda Godfrey Elikalia
A review on the epidemiology and diagnosis of human taeniasis and bovine cysticercosis with special reference to East Africa is given. All humans are susceptible to the adult tapeworm, T. saginata. Cattle, is the predominant intermediate host, young animals being more susceptible than older ones. Susceptibility of a few wild ruminants makes them potential reservoirs of infection. Characteristics of T. saginata, including a long life span, a high reproductive potential, spontaneous shedding of proglottids from human carriers, occult nature of the cysticerci in cattle, etc, contribute to maintenance of infections. Dispersion and survival of T. saginata eggs are determined by sanitation, personal hygiene, coprophagous animals and weather conditions. Prevalence rates of cysticercosis in cattle reported from various countries depend on local meat hygiene legislations, efficiency of meat inspection, and record keeping in the abattoirs. In this thesis, factors promoting the spread of T. saginata infections in Tanzania were investigated, by interview information from 105 cattle owners, belonging to Masai, Arusha, Iraqw, Gogo and Rangi ethnic groups, from 52 villages in Tanzania. Taeniasis and cysticercosis were reported as common problems among members of the ethnic groups interviewed. Lack of awareness of the source of human tapeworms, scarcity of medicines against taeniasis, habits of consuming raw beef, consumption of uninspected meat, defaecation in the bush, were some of the outstanding factors elucidated. The details of this investigation are discussed and it is concluded that some of the observations need confirmation through further studies in the villages of the ethnic groups concerned. Prevalence rates of taeniasis recorded at Mbulu Hospital were 10% in 1990 and 21% in 1991. In a separate investigation, cysticercosis was detected in 52 (10.5%) out of 496 cattle xi slaughtered in municipal abattoirs of Arusha, Dodoma, Iringa, Morogoro and Mpwapwa districts in Tanzania during the period between June 1991 and November 1991. The prevalence rates in the individual abattoirs were 16.7% (Arusha), 8% (Dodoma), 9.6% (Iringa), 6.5% (Morogoro) and 7.6% (Mpwapwa). The overall annual prevalence rates of cysticercosis in the Dodoma and Iringa regions were lower than the rates officially recorded in these abattoirs. The results are discussed in relation to sources of infection, endemicity of cysticercosis, efficiency of meat inspection, and records keeping in the abattoirs in the country. In a detailed examination, anatomical distribution of cysticerci of T. saginata (864) was analyzed in zebu cattle at Morogoro abattoir in Tanzania. The cysticerci were found located in the examined tissues preferentially in the following order: heart, M. triceps brachii, tongue, M. psoas and masseter muscles. The liver had relatively high numbers of cysts and is thus considered an important predilection site. Examination of the predilection sites for detecting carcasses positively infected with cysticerci of T. saginata revealed the following efficiency: 80% (heart), 80% (M. triceps brachii), 60% (masseter muscles), 60% (tongue) and 53% (liver). However examination of the heart, M. triceps brachii and the liver together detected all infected carcasses. Most (60%) of the infected carcasses had viable cysticerci. In conclusion, T. saginata taeniasis and cysticercosis are major, but underestimated problems in Tanzania. The diagnostic methods of cysticercosis in cattle and taeniasis in humans all have inherent limitations. But nevertheless, their sensitivity may be significantly be improved and the usual control may be more efficient. The various chapters of the thesis include discussions on ways to improve public control measures and educate consumers and herdsmen. SAMMENDRAG (Summary in Danish) Taenia saginata cysticercose hos kvaeg i Tanzania Afhandlingen indledes med en litteraturoversigt over epidemiologi og diagnostik af human taeniiasis og bovin cysticercose med saerlig omtale af forholdene i 0stafrika. Alle mennesker er modtagelige for infektion med baendelormen T. saginata. Kvaeget er den almindeligste mellemvaert, og yngre dyr er mere modtagelige end aeldre. Nogle f
Development and evaluation of a novel vaccine storage device for effective vaccination strategy against rabies
(Sokoine University of Agriculture, 2023) Lugelo, Ahmed Kambinda
Canine-mediated human rabies has the highest case fatality rate of any known infectious disease and kills approx. 59,000 people annually, with most deaths being children under 15 years. The vast majority (99%) of these fatalities occur in Africa and Asia, where access to appropriate Post Exposure Prophylaxis (PEP) is limited and where canine vaccination is either inconsistently applied or, commonly, non-existent. Epidemiological studies have shown that rabies has epidemiological features that make elimination a realistic and feasible goal, with success demonstrated by comprehensive mass dog vaccination programmes in the Americas, Western Europe and Japan. In rabies endemic countries, dogs are often vaccinated using annually delivered central point clinics at the village level on an annual basis. For this method to be effective at least 70% of the dog population must be vaccinated to maintain herd immunity between campaigns. However, studies have shown that only a few programmes utilising this approach have attained this level of coverage, highlighting the need for alternative approaches to address this challenge. The current study was carried out to develop an alternative strategy for delivering and maintaining herd immunity over time in low-resource field settings. Through an iterative process of improvement and testing with local communities in northern Tanzania, a passive cooling device “Zeepot” for storage of thermotolerant rabies vaccines was developed at a cost of $11 per unit. The results from a non-inferiority randomised controlled trial showed that the serological response of dogs vaccinated using Nobivac ® Rabies vaccine stored within the Zeepot was not inferior to the response of dogs vaccinated using cold-chain stored vaccine (z = 1.1, df = 313, p-value = 0.25). Indeed, the 28-day post vaccination group geometric mean titre was 1.8 IU/ml and 2.0 IU/ml for dogs vaccinated with vaccines stored under cold-chain versus non-cold-chain respectively. Moreover, the percentage of dogs that seroconverted in each arm was almost identical (85%). There was a positive linear trend between Body Condition Score (O.R. 2.2, 95% CI: 1.1 – 5.1) and seroconversion, suggesting that dogs of poor condition may not respond as expected to vaccination. Our study demonstrated that the potency of Nobivac ® Rabies vaccine is not impacted following storage in Zeepot Clay locally designed Passive Cooling Device. A total of 17,571 dogs were vaccinated in the field study that was conducted to evaluate the effectiveness of the standard delivery method also known as Central Point Vaccination (CPV) and a novel strategy, Decentralized Continuous Vaccination (DCV), 2654 dogs were vaccinated using CPV and 14,917 dogs were vaccinated through three sub-strategies of DCV. At time point 1 (1 month after the initial vaccination campaign), the vaccination coverage achieved by DCV coverage was higher (64.10%; 95CI 62.12 – 66.04) than for CPV (35.86%; 95CI 32.59 – 39.51). Similarly, at time point 2 (11 months after the vaccination campaign) the coverage in DCV (60.67%; 95CI 58.47 – 62.84) remained high while the coverage in pulse vaccination was lower (32.10%; 95CI 28.82-35.57). Overall, > 84% of the respondents were satisfied with the vaccination services they received. DCV has the potential to consistently maintain population level immunity. Overall, this thesis showed that Zeepot Clay has a utility for storing thermotolerant vaccines at sub-ambient temperatures. Moreover, DCV has the potential to consistently maintain population level immunity making it a useful strategy to further investigate for scaling up of mass dog vaccination in East Africa. Together the findings of this work have potential application for rabies elimination programmes, particularly in achieving the global target of zero human deaths by 2030 and potentially for use in other vaccination programmes aiming to reach remote or inaccessible communities.
Reproduction of East-African bats may guide risk mitigation for coronavirus spillover
(BMC, 2020-02-07) Montecino-Latorre, Diego; Goldstein, Tracey; Gilardi, Kirsten; Wolking, David; Van Wormer, Elizabeth; Kazwala, Rudovick; Ssebide, Benard; Nziza, Julius; Sijali, Zikankuba; Cranfield, Michael; PREDICT Consortium; Mazet, Jonna A. K.
Background: Bats provide important ecosystem services; however, current evidence supports that they host several zoonotic viruses, including species of the Coronaviridae family. If bats in close interaction with humans host and shed coronaviruses with zoonotic potential, such as the Severe Acute Respiratory Syndrome virus, spillover may occur. Therefore, strategies aiming to mitigate potential spillover and disease emergence, while supporting the conservation of bats and their important ecological roles are needed. Past research suggests that coronavirus shedding in bats varies seasonally following their reproductive cycle; however, shedding dynamics have been assessed in only a few species, which does not allow for generalization of findings across bat taxa and geographic regions. Methods: To assess the generalizability of coronavirus shedding seasonality, we sampled hundreds of bats belonging to several species with different life history traits across East Africa at different times of the year. We assessed, via Bayesian modeling, the hypothesis that chiropterans, across species and spatial domains, experience seasonal trends in coronavirus shedding as a function of the reproductive cycle. Results: We found that, beyond spatial, taxonomic, and life history differences, coronavirus shedding is more expected when pups are becoming independent from the dam and that juvenile bats are prone to shed these viruses. Conclusions: These findings could guide policy aimed at the prevention of spillover in limited-resource settings, where longitudinal surveillance is not feasible, by identifying high-risk periods for coronavirus shedding. In these periods, contact with bats should be avoided (for example, by impeding or forbidding people access to caves). Our proposed strategy provides an alternative to culling – an ethically questionable practice that may result in higher pathogen levels – and supports the conservation of bats and the delivery of their key ecosystem services.
Factors lowering levels of rabies vaccination: a case of Kibaha town District of Tanzania
(Tanzania Veterinary Journal, 2019) Chikoondo, F. M; Majid, K.S; Muhairwa, A.P; Mpelumbe-Ngeleja, C.A.R
A study was conducted in Kibaha Town Council of Pwani Region of Tanzania to survey the probable factors that negatively affected the anti-rabies vaccinations leading to low percent coverage in some selected wards. The data used in this study were gathered from households keeping dogs and cats and institutions, using a semi-structured questionnaire and interviews. Another set of data was the record of the rabies control programme at the district veterinary office. Analysis of the data was done using SPSS.16, Microsoft Excel 2007 and EpiInfo TM 7. The enquiry instrument centred on three main fields, namely, knowledge of respondents about rabies, responsible dog ownership and their perception of issues pertaining to the conduct of the rabies control programme. The results showed that the last round of vaccination covered dogs for 57% of the sampled households in the selected wards. A huge percentage of the respondents (64%) kept the wrong perception that clinical rabies could be cured. Only 34% of the respondents indicated that they had been taught about rabies in a WHO project area. It was also learnt that there was an outbreak of rabies in the district after 2 years of consecutively vaccinating the dogs in the area. The Chi- square test for linear trends showed very highly significant statistical differences in the progression of numbers of dogs vaccinated over the years (p<0.05; = 0.0000). This study concludes that, lack of sufficient knowledge on rabies and negative attitude towards the control programme were the biggest drawbacks on the vaccination coverage.
Socio-cultural practices related to taenia solium taeniosis and cysticercosis Epidemiology in endemic areas
(TVA, 2020) Kajuna, F.F; Mwang’onde, B.J; Holst, C.; Ngowi, B.; Noll, J; Winkler, A.S.; Ngowi, H.A.
Socio-cultural settings and lifestyles of communities in Taenia solium taeniosis/cysticercosis (TSTC) in endemic areas influence significantly the epidemiology of the disease. This study investigated the community perceptions and practices influencing the occurrence and endemicity of TSTC. A cross- sectional survey focusing on pig-keeping households was carried out in three wards of Iringa District Council as a representative of other TSTC endemic areas. Questionnaire and observation checklists were employed for data collection. Eighty-seven (99%) of the 88 surveyed households had pit latrines, and 84(95%) of the households were found using their latrines. These latrines varied from good to a very good quality according to subjective qualitative scores. About 294 (85%) pigs were enclosed and 52(15%) were free roaming. The results indicated poor adherence to routine pig inspection at sales (50% inspection) and less pork inspection at slaughter (50% uninspected). Furthermore, there were no authorized centres for slaughter and sales. Health Officers and farmers were comfortable with the boiling form and home prepared pork (>90%). Health Officers perceived deep-frying and roasting of pork as inappropriate preparation methods. Generally, the social cultural practices and life style in the study area promoted the endemicity of Taenia solium life cycle. A strategy for surveillance on socio- cultural practices in the community is important during planning for TSTC control. This community needs sustainable health education on TSTC diseases control.

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