Department of Veterinary Pathology

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Correlation between type of adaptive immune response against porcine circovirus type 2 and level of virus replication
(Mary Ann Liebert, Inc., 2005-06-01) Meerts, Peter; Gucht, Van S; Cox, Eric; Vandebosch, A; Nauwynck, H. J
Porcine circovirus 2 (PCV2) replication is characterized by high variation among infected pigs. This study investigated the role of immunologic responses in causing this variation. Twelve gnotobiotic pigs were inoculated with PCV2. Four of these pigs were treated with cyclosporin A (CysA) to monitor the effect of the adaptive immunity on the development of the PCV2 infection. Through lymph node biopsies at 10, 15, and 21 days postinoculation (DPI), PCV2 replication in lymphoid tissues was monitored. The production of total PCV2-specific and PCV2-neutralizing antibodies was followed, together with interferon-γ (IFN-γ) mRNA expression levels in peripheral blood monocytes as a marker for cellular immunity. In general, the CysA-treated pigs showed the highest PCV2 titers, indicating that the adaptive immunity is necessary to restrain PCV2 replication. Three different PCV2 replication patterns were observed in …
Large induction of type III deiodinase expression after partial hepatectomy in the regenerating mouse and rat liver
(Oxford University Press, 2008-09-11) Kester, M. H. A.; Matondo, R. B.; Toussaint, M. J. M.; Punt, C. A.; Aarnio, A. M.; Darras, V. M.; Everts, M. E.; Bruin, A.; Visser, T. J.
The deiodinase types 1 (D1) and 2 (D2) catalyze the activation of T4 to T3, whereas type 3 deiodinase (D3) catalyzes the inactivation of T3 and T4. D3 plays a key role in ontrolling thyroid hormone bioavailability. It is highly expressed during fetal evelopment, but also in other processes with increased cell proliferation, e.g. in vascular tumors. Because tissue regeneration is dependent on cellular proliferation and is associated with activation of fetal genes, we evaluated deiodinase activities and mRNA expression in rat and mouse liver, as well as the local and systemic thyroid hormone status after partial hepatectomy (PH).Weobserved that in rats, D3 activity was increased 10-fold at 20 h and 3-fold at 48 h after PH; D3 mRNA expression was increased 3-fold at 20 h. The increase in D3 expression was associated with maximum 2- to 3-fold decreases of serum and liver T3 and T4 levels at 20 to 24 h after PH. In mice, D3 activity was increased 5-fold at 12 h, 8-fold at 24 h, 40-fold at 36 h, 15-fold at 48 h, and 7-fold at 72 h after PH. In correlation with this, D3 mRNA was highest (6-fold increase), and serum T3 and T4 were lowest at 36 h. Furthermore, as a measure for cell proliferation, 5-bromo-2_-deoxyuridine incorporation peaked at 20–24 h after PH in rats and at 36 h in mice. No significant effect on D1 activity or mRNA expression was found after PH. D2 activity was always undetectable. In conclusion, we found a large induction of hepatic D3 expression after PH that was correlated with an increased cellular proliferation and decreased serum and liver T3 and T4 levels. Our data suggest that D3 is important in the modulation of thyroid hormone levels in the regenerating liver, in which a decrease in cellular T3 permits an increase in proliferation
Deletion of the serotonin transporter in rats disturbs serotonin homeostasis without impairing liver regeneration
(American Physiological Society, 2009-04-01) Matondo, RB; Punt, C; Homberg, J; Toussaint, MJM; Kisjes, R; Korporaal, SJA; Akkerman, JWN; Cuppen, E; de Bruin, A
The serotonin transporter is implicated in the uptake of the vasoconstrictor serotonin from the circulation into the platelets, where 95% of all blood serotonin is stored and released in response to vascular injury. In vivo studies indicated that platelet-derived serotonin mediates liver regeneration after partial hepatectomy. We have recently generated serotonin transporter knockout rats and demonstrated that their platelets were almost completely depleted of serotonin. Here we show that these rats exhibit impaired hemostasis and contain about 1–6% of wild-type serotonin levels in the blood. Despite the marked reduction of serotonin levels in blood and platelets, efficient liver regeneration and collagen-induced platelet aggregation occur in rats lacking the serotonin transporter. These results provide evidence that liver regeneration is not dependent on the release of serotonin from platelets. Our findings indicate that very low levels of serotonin in blood are sufficient for liver regeneration.
Lymphoid leukosis in commercial layers in Morogoro
(Tanzania Veterinary Association, 2010) Mathew, C.; Matondo, R. B.; Malago, J. J.; Maselle, R. M.; Mwamengele, G. L.
A total of 25 commercial layer carcases from seven poultry farms in Morogoro municipality were examined for gross and histopathological changes. Grossly, splenomegally, renomegally and hepatomegally were striking features. Both the liver and spleen were almost twice the size of normal organs. The surfaces of the liver, spleen, kidneys, lungs and the heart had yellowish white to grey multifocal and focally extensive patches of variable sizes. The lungs were consolidated. Histologically, the liver, spleen, kidneys, lungs, and the heart had heavy infiltration of large lymphocytes with abundant cytoplasm and poorly stained eosinophilic cytoplasm. There were also small lymphocytes with scant cytoplasm and deeply stained eccentrically placed nuclei and numerous mitotic figures. The history, clinical signs, and pathologic features were suggestive of avian lymphoid leukosis
Effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus) under small scale fish farming systems in Morogoro, Tanzania
(Livestock Research for Rural Development, 2011) Mdegela, R H; Omary, AN; Mathew, C; Nonga, HE
A cross-sectional study was conducted in small scale fish farming systems in Morogoro urban and rural area between December 2007 and February 2008 to determine the effect of pond management on prevalence of intestinal parasites in Nile Tilapia (Oreochromis niloticus). Water physicochemical parameters in fish ponds and the risk factors for intestinal parasites were determined. Information on pond type and cleanness, feeding and general pond management was also gathered through questionnaires and participant observations during the sample collection. One fifty three adult O. niloticus from 13 ponds were examined. It was found that most ponds (69%) were small and of earthen type, 77% were clean and were using river water. Up to 92% of farmers changed pond water regularly and almost all farmers reported to use maize bran as the main feed for fish. Farmers used different types of animal manure to fertilize the ponds. The observed water physicochemical levels were within the normal range for fish water ponds as recommended by FAO. The prevalence of intestinal parasites was 16.3%. Specifically, 15% of fish had Eimeria oocysts while 1.3% had unidentified flukes. Prevalence of parasites was significantly higher (P < 0.05) in ponds located in rural (18.7%) than in urban areas (6.7%). Significantly (P<0.05) higher prevalence of parasites was observed in fish ponds using river water (18.8%) than in ponds using rain water (0%). Pond type was also a risk factor as there was a significantly (P < 0.05) higher parasite infection rates in earthen ponds (20.9%) than in fish reared in concrete ponds (4.7%). It is concluded that earthen fishponds, keeping fish in rural areas and using river water in ponds predisposes fish to intestinal parasites. Good water quality management and proper fish husbandry techniques will eliminate most parasitic infection and improve fish production.
Gastrointestinal disorders: symptoms, treatment and prevention
(Nova Science Publishers, Inc, 2012) Malago, J. J.
The digestive system, which extends from the mouth to the anus, is responsible for receiving food, breaking it down into nutrients (digestion), absorbing the nutrients into the bloodstream, and eliminating the undigestible parts of food from the body. It consists of the mouth, throat, esophagus, stomach, small intestine, large intestine, rectum, and the anus. In addition, the digestive system consists of accessory digestive glands namely the liver, exocrine pancreas, and the biliary system consisting of the gallbladder and the bile duct. Disorders of the gastrointestinal system can be divided into: 1. Upper gastrointestinal disorders which involve diseases of the oral cavity, esophagus, and the stomach. Disorders of the oral cavity include those in the mouth, parotid and other salivary glands, and the pharynx. 2. Intestinal disorders which include disorders of the small intestine, large intestine, those involving both small and large intestine, rectum, and the anus. Conditions affecting the small intestine include conditions like enteritis (duodenitis, jejunitis, ileitis), duodenal (peptic) ulcer, and malabsorption. Those affecting the large intestine include appendicitis, colitis, functional colonic disease (e.g. irritable bowel syndrome, intestinal pseudoobstruction), megacolon, and diverticular disease. Examples of conditions occurring in both large and small intestines are enterocolitis and Crohn’s disease. Conditions affecting the rectum and the anus include proctitis, rectal prolapsed, anorectal fistula/fissure, and hemorrhoids. 3. Accessory digestive gland disorders are disorders of the liver, exocrine pancreas, gallbladder and bile duct. Examples of conditions affecting the liver include disorders of the liver parenchyma such as acute viral hepatitis (hepatitis A,B,C,D,E), yellow fever, cirrhosis, haemochromatosis and tumors like hepatocellular carcinoma. The biliary system could suffer from cholecystitis, gallstones, and cholesterolosis whereas the exocrine pancreas may have developmental abnormalities, pancreatitis, and pancreatic insufficiency. Owing to the nature and location of the condition, symptoms and subsequent treatment and prevention vary significantly. In general terms, congenital disorders may need surgical correction while infectious cases need antimicrobial therapy following identification of specific causative agents. Most of the gastrointestinal disorders are treated symptomatically. In this case, therapy is instituted to correct effects of symptoms such as vomiting and diarrhea (antiemetics, oral rehydration salts, intravenous fluid infusion) or muscular disorders like esophageal spasms where long acting anticholinergics or calcium blockers such as nifedipine relief the symptoms. Thus use of antimicrobials, surgery, and symptomatic therapy are major approaches to treatment of gastrointestinal disorders. Apart from congenital and inherited disorders, many gastrointestinal conditions can be prevented by proper and safe nutrition as well as drinking of safe water. Some specific conditions, such as gastritis, gastric and duodenal ulcers, inflammatory bowel diseases, cirrhosis, liver failure, and pancreatitis may need very special attention for treatment. In this book chapter, current findings on research and medical practice on symptoms, treatment and prevention of specific gastrointestinal disorders will be described in detail.
Clinico-pathological findings of the 2011 outbreak of peste des petits ruminants (PPR) in Tandahimba district, southern Tanzania
(Research Opinions in Animal and Veterinary Sciences, 2012) Matondo, R. B.; Muse, E. A.; Karimuribo, E. D.; Misinzo, G.; Albano, M. O.; Gitao, G. C.
Although PPR outbreaks were reported in Northern Tanzania since 2008, there has been no description of the clinical or pathological manifestation of the disease, an important criterion in guiding veterinarians and farmers on proper recognition and diagnosis of the disease. A study was therefore conducted to investigate and describe clinical signs and pathological lesions associated with 2011 Peste des petits ruminants (PPR) outbreak in goats and sheep in Tandahimba district located in Southern Tanzania. The investigation involved taking history and conducting clinical examination of PPR suspected cases (25 goats and 3 sheep) in the study district which had neither a history of vaccination against PPR nor previous illness due to PPR. This work was complemented by collection of pathological samples and specimens for laboratory examination. A detailed post-mortem was performed on three sacrificed animals followed by collection of specimens including lungs, liver, spleen and lymph nodes for histopathological examination. Clinical samples from 30 animals which included swabs from ocular, nasal and mouth lesions were also collected for confirmation of PPR through detection of PPR ribonucleic acid using reverse transcription polymerase chain reaction (RT-PCR). Clinical examinations of the cases showed signs suggestive of PPR including severe depression, high fever (41oC), anorexia, muco-pulurent nasal discharge, erosive and necrotic stomatitis, mild diarrhoea and skin nodules. Post mortem examination showed evidence of pneumonia including lung congestion and consolidation, increased thickness of inter-alveolar walls, moderate infiltration of inflammatory cells in bronchiolar subepithelial and perivascular layers. Overall 56.7% of the samples (n=30) tested were positive for PPR by RTPCR. This study has confirmed and described the presence of PPR in southern Tanzania. A more detailed study including other districts is recommended to provide more information regarding the magnitude and factors associated with PPR in Southern Tanzania.
Pathogenic Escherichia fergusonii and Staphylococcus gallinarum co-infection in a free-ranging domestic chicken
(ROAVS, 2012) Misinzo, G; Mathew, C; Matondo, RB; Jumapili, F; Ludosha, M; Masola, S; Munisi, W; Viaene, W; Doorsselaere, J.
Examination was carried out in an emaciated and depressed free-range domestic chicken from Mpwapwa where multiple cases of a similar condition were observed in 2010. A loosely attached unilateral nodule on the ventral aspect of the right eye and similar other nodules around the base of feathers mainly on dorsal aspects of wings, neck and head were observed. The cut nodules were yellowish with a firm and cheesy consistency surrounded by hyperaemic skin. In addition, multiple grey foci of variable size on liver and localized areas of hyperaemia on duodenal mucosa with mucoid exudates in the lumen were observed. On histopathology, the nodular lesions consisted of hyperplastic feather follicles with broad bands of keratinocytes and extension of follicular epithelium into surrounding dermis. In addition, luminal folliculitis in the skin and hepatic portal vasculitis were observed. Excised lesions from the eye, skin and liver were streaked on bacteriological agar with or without penicillin and streptomycin to isolate bacteria. Bacteria grew in agar without antibiotics but not in agar containing antibiotics. Bacterial colonies were subcultured and passaged four times to obtain pure cultures. Based on colony morphology, two types of bacteria were isolated from each of the organs. DNA was extracted from bacteria followed by amplification and sequencing of the 16S rDNA using 27F and 1492R primers. Sequence similarity search in GenBank showed that the bacteria were Escherichia fergusonii and Staphylococcus gallinarum. The present study shows that the chicken had E. fergusonii and S. gallinarum co-infection sensitive to penicillin and streptomycin
Peste des Petits Ruminants (PPR) outbreak in southern, Tanzania
(RUFORUM, 2012) Muse, E. A.; Matondo, R. B.; Karimuribo, E. D.; Misinzo, G.; Mellau, L. S. B.; Msoffe, P. L. M.; Albano, M. O.; Gitao, G. C.
Peste des petits ruminants (PPR) was first confirmed in Tanzania in 2008, however description of clinical or pathological signs was not carried out although this is important to assist quick identification and reporting of PPR cases by both livestock keepers and field-based animal health workers. A study was therefore conducted to investigate and describe clinical signs and pathological lesions associated with suspected PPR cases in southern Tanzania. It involved history taking and clinical examination of suspected cases of 25 goats and 3 sheep. Post- mortem examination of some cases was performed followed by collection of specimens for histopathological examination. Swabs were also collected for confirmation of PPR by detecting ribonucleic acid using reverse transcription polymerase chain reaction (RT-PCR). Serum samples were analysed using competitive enzyme linked immunosorbent assay (cELISA). Severe depression, high fever, anorexia, muco-pulurent nasal discharge, erosive and necrotic stomatitis, mild diarrhoea and skin nodules were major signs suggestive of PPR. Post mortem examination showed evidence of pneumonia including lung congestion and consolidation. RT-PCR confirmed presence of the PPR virus in samples and serum antibodies showed seroprevalence of 31%.
Detection of Contagious bovine pleuropneumonia in condemned cattle lungs at Morogoro municipal abattoir in Tanzania
(Tanzania Veterinary Journal, 2013) Malago, J. J.; Mlay, J. D.
Control of re-emerged Contagious bovine pleuropneumonia (CBPP) in Tanzania in 1990s left spots of unvaccinated animals in various areas. Some of these animals were carriers of CBPP and have presumably continued to be sources of infection to other animals. We made an abattoir follow-up of slaughtered animals to understand whether the disease is still present in Tanzania. A total of 13 condemned lungs due to CBPP-like lesions at Morogoro municipal abattoir were collected from November 2011 to April 2012 and examined grossly, histologically and bacteriologically. Typical gross lesions of CBPP including expanded interlobular septa, sequestration, coalescing lungs, and fibrinonecrotic exudation were observed. Histologically, we observed fibrinonecrotic exudates filling and expanding the alveoli, desquamation of alveolar epithelial cells, lymphoplasmacytic infiltration in the interalveolar septa and around bronchi, bronchioles, and blood vessels, and vasculitis with subsequent vascular rupture and hemorrhage. Mycoplama cultures in two samples isolated Mycoplasma organisms with “fried egg appearance”, typical of Mycoplasma mycoides mycoides small colony type, the causative agent of CBPP. We conclude that CBPP is still prevalent in Tanzania and continues to pose a potential impending epidemic in the future.
Detection of Contagious bovine pleuropneumonia in condemned cattle lungs at Morogoro municipal abattoir in Tanzania
(Tanzania Veterinary Journal, 2013) Malago, J. J.; Mlay, J. D.
Control of re-emerged Contagious bovine pleuropneumonia (CBPP) in Tanzania in 1990s left spots of unvaccinated animals in various areas. Some of these animals were carriers of CBPP and have presumably continued to be sources of infection to other animals. We made an abattoir follow-up of slaughtered animals to understand whether the disease is still present in Tanzania. A total of 13 condemned lungs due to CBPP-like lesions at Morogoro municipal abattoir were collected from November 2011 to April 2012 and examined grossly, histologically and bacteriologically. Typical gross lesions of CBPP including expanded interlobular septa, sequestration, coalescing lungs, and fibrinonecrotic exudation were observed. Histologically, we observed fibrinonecrotic exudates filling and expanding the alveoli, desquamation of alveolar epithelial cells, lymphoplasmacytic infiltration in the interalveolar septa and around bronchi, bronchioles, and blood vessels, and vasculitis with subsequent vascular rupture and hemorrhage. Mycoplama cultures in two samples isolated Mycoplasma organisms with “fried egg appearance”, typical of Mycoplasma mycoides mycoides small colony type, the causative agent of CBPP. We conclude that CBPP is still prevalent in Tanzania and continues to pose a potential impending epidemic in the future.
Contribution of microbiota to innate and acquired gut immunity during health and disease
(Nova Science Publishers, Inc, 2014) Malago, J. J.
The contribution of intestinal epithelium to the innate immune system includes detecting luminal microbes, transducing signals, and activating inflammatory mediator release by epithelial and other cells of the immune system like the antigen presenting cells. Microbial antigens are detected by cells of the innate immune system through their pattern recognition receptors (PRRs). The PRRs recognize microbe-associated molecular patterns and generate signals that activate transcription pathways like nuclear factor kappa B and mitogen activated protein kinases. This activation leads to production of inflammatory and growth mediators that drive the immune system to elicit tolerance or immune response designated at maintaining immune homeostasis. Key to this signaling is the gut microbiota. Intestinal epithelial cell sensing of optimally balanced microbiota favors immune homeostasis whereas sensing under disrupted microbiota impairs immune function and predisposes to disease. Understanding the PRR-microbiota signaling would be useful in designing therapeutics for various immune-mediated disorders caused by imbalances of microbiota.
Prevalence and mean intensity of ectoparasite infections in pond reared Nile tilapia (Oreochromis niloticus) in Morogoro Tanzania.
(Tanzania Veterinary Journal, 2014) Mathew, C; Mwamengele, G; Mdegela, R. H.; Kassuku, A. A.
cross sectional study was carried out between September 2007 and September 2008 to investigate the prevalence and mean intensity of ectoparasite infections on the gills and skin of Nile tilapia (Oreochromis niloticus) in Morogoro, Tanzania. A total of 229 fish from 19 ponds were studied. Trichodina spp. and Monogeneans were the only ectoparasites observed. Overall prevalence of ectoparasites in the study area was 68% and the average mean intensity was 5.3. Trichodina spp. were more prevalent (P<0.05) than Monogeneans. Gills were more affected with parasites than the skin (P<0.05). There was no strong relationship between water quality and prevalence and mean intensity of parasites. Prevalence and mean intensity varied in different ponds due to different management practices and the knowledge of fish husbandry. Parasite infection was significantly higher in urban than in rural areas (P<0.05). There is a need for farmers to be trained on proper fish husbandry and pond management in order to reduce the risk of parasite multiplication in the ponds and hence infection rate.
The role of probiotics on immune mediated disorders
(Nova Science Publishers, Inc, 2014) Malago, J. J.
According to hygiene hypothesis, diseases of the immune system are increasing with socio-economic and sanitary conditions. This is evidenced by high incidences of allergic and autoimmune diseases in Western countries than in developing countries. The underlying factor is disruption of normal microbiota and their associated beneficial effects on intestinal mucosal immunity. Thus the pathogeneses of these disorders appear to revolve around impaired ability of the intestinal microbiota to effectively modulate and thus balance the body immune responses. As a result the immune system reacts excessively to antigens that would otherwise be tolerated and thus results in allergic reactions. Alternatively, the immune system reacts to self-antigens to cause autoimmune diseases. Some of these disorders are characterized by persistent production of inflammatory mediators leading to chronic inflammation and tissue damage. Several reports have indicated that oral administration of excessive numbers of selected members of microbiota, so called probiotic bacteria, prevents, treats, and improves the conditions of patients with immune-mediated disorders like allergy, inflammatory bowel diseases, and type 1 diabetes mellitus. Current knowledge suggests that probiotic bacteria mediate their beneficial effects via modulation of the immune system to balance its responses and institute protection. Herein the knowledge of new research on the role of probiotic bacteria on the development of some of the immune mediated diseases is reviewed in order to provide an insight in the role of probiotics in health and disease.
Risks of enteropathogen infection in humans and cattle associated with manure management in urban and peri-urban areas of Morogoro, Tanzania
(Sokoine University of Agriculture, 2014) Lupindu, Athumani Msalale
Urban population growth has created an increase in demand for food including those of animal origin. In response to ample market, urban and peri-urban livestock farming has expanded both in the number of livestock and the number of households engaged in livestock keeping. As a result, human-animal interaction has increased and concurrent increase in manure production within the same land space has increased human-manure-environment contact. The present study was aimed at investigating cattle and manure management practices and associated risks of manure-borne enteropathogen infection to humans and animals and environmental contamination in urban and peri-urban settings of Morogoro, Tanzania. One hundred and nineteen smallholder dairy cattle keeping households from urban and peri-urban areas of Morogoro municipal, Morogoro rural and Mvomero districts were randomly selected for the study. To each cattle keeping household, a non-cattle keeping neighbor from within a radius of 100m was selected and a pair formed a cluster. Administration of structured questionnaires to cattle keepers and non-cattle keepers, together with observations was used to collect information about cattle and manure management practices. Individual fecal samples were collected from all cattle present at the household registered for the study. Stool samples from individuals from cattle keeping households and non-cattle keeping neighbors as well as soil and water samples were collected for the purpose of isolating zoonotic Salmonella spp., non-sorbitol fermenting diarrheagenic E. coli and non-pathogenic commensal E. coli strains. In total, there were 446 cattle fecal, 201 stool, 201 soil and 201 water samples for bacteria isolation. Zoonotic Salmonella species were isolated on Salmonella-Shigella agar and characterized by biochemical and standard serological methods. Diarrheagenic E. coli were isolated from sorbitol MacConkey agar and characterized by conventional biochemical, serological and antimicrobial susceptibility tests and molecular methods such as PCR and DNA hybridization. The non-pathogenic E. coli isolated from MacConkey agar were screened for double resistance for ampicillin and tetracycline using Petri film Select E. coli count plate and later analysed for genetic relatedness by Pulsed Field Gel Electrophoresis (PFGE). Logistic regression was used to quantify the risks for transmission of E. coli between cattle, humans, water and soil based on PFGE results. It was revealed that cattle from different herds were allowed to mix and there was indiscriminate defecation during grazing. Manure collection, conveyance and disposal resulted into direct human contact with manure and manure was disposed off within and around residential areas either as fresh or composted. The prevalence of shiga toxin-producing E. coli (STEC) O157:H7 in cattle was 0.9% (95% CI: 0.29 –237 2.15) while the prevalence of all STEC strains in cattle was 1.6% (95% CI: 0.69 – 3.08). The overall prevalence of diarrheagenic E. coli in cattle was 2.2% (95% CI: 0.99 – 3.67) and 0.5% (95% CI: 0.025 – 2.44) in water sources. This shows that cattle remain potential source of pathogenic E. coli to humans and environment. Among the non-sorbitol fermenting E. coli isolates, one Extended Spectrum Beta Lactamase (ESBL)-producing isolate showed the Multilocus Sequence Typing (MLST) type ST131 that causes antimicrobial-resistant infections in humans. Zoonotic Salmonella strains such as Salmonella amager, S. kentucky and S. weltevreden were isolated from humans and cattle. Overall, four samples out of 1046 (0.38%) were positive, while the prevalences of Salmonella in humans and cattle were 1% and 0.45% respectively. Isolation of S. amager in asymptomatic human subject shows that, the pathogen that was previously reported to cause gastroenteritis outbreak in humans, may have lost its virulence characteristics but still exists within the human population. There was transmission of E. coli between cattle, humans, soil and water within and between clusters due to manure management. Out of 44 clusters from which ampicillin and tetracycline resistant E. coli were isolated, 16 clusters (36%) had at least one isolate that was 100% identical to another isolate but from another source within the same epidemiological unit. Cattle (OR=19.2, CI: 2.04-179.8) and manure (OR=0.4, CI: 0.17-0.89) management practices were the risk factors for E. coli transmission between cattle, humans, soil and water. Cattle and manure management practices in urban and peri-urban areas of Morogoro put humans and animals at risk of infection with pathogens including E. coli O157:H7 and ESBL producing ST131 strains while contaminating the environment. Therefore, there is a need for formulation and enforcement of manure management guidelines that safeguide human, animals and the environment.
Contribution of microbiota to innate and acquired gut immunity during health and disease
(Nova Science Publishers, Inc, 2014) Malago, J. J.
The contribution of intestinal epithelium to the innate immune system includes detecting luminal microbes, transducing signals, and activating inflammatory mediator release by epithelial and other cells of the immune system like the antigen presenting cells. Microbial antigens are detected by cells of the innate immune system through their pattern recognition receptors (PRRs). The PRRs recognize microbe-associated molecular patterns and generate signals that activate transcription pathways like nuclear factor kappa B and mitogen activated protein kinases. This activation leads to production of inflammatory and growth mediators that drive the immune system to elicit tolerance or immune response designated at maintaining immune homeostasis. Key to this signaling is the gut microbiota. Intestinal epithelial cell sensing of optimally balanced microbiota favors immune homeostasis whereas sensing under disrupted microbiota impairs immune function and predisposes to disease. Understanding the PRR-microbiota signaling would be useful in designing therapeutics for various immune-mediated disorders caused by imbalances of microbiota.
Detection of serum neutralizing antibodies to Simbu sero-group viruses in cattle in Tanzania.
(BMC Veterinary Research, 2015) Mathew, C; Klevar, S; Elbers, A; van der Poel, W; Kirkland, P; Godfroid, J; Mdegela, R; Mwamengele, G; Stokstad, M
Background: Orthobunyaviruses belonging to the Simbu sero-group occur worldwide, including the newly recognized Schmallenberg virus (SBV) in Europe. These viruses cause congenital malformations and reproductive losses in ruminants. Information on the presence of these viruses in Africa is scarce and the origin of SBV is unknown. The aim of this study was to investigate the presence of antibodies against SBV and closely related viruses in cattle in Tanzania, and their possible association with reproductive disorders. Results: In a cross-sectional study, serum from 659 cattle from 202 herds collected in 2012/2013 were analyzed using a commercial kit for SBV ELISA, and 61 % were positive. Univariable logistic regression revealed significant association between ELISA seropositivity and reproductive disorders (OR = 1.9). Sera from the same area collected in 2008/2009, before the SBV epidemic in Europe, were also tested and 71 (54.6 %) of 130 were positive. To interpret the ELISA results, SBV virus neutralization test (VNT) was performed on 110 sera collected in 2012/2013, of which 51 % were positive. Of 71 sera from 2008/2009, 21 % were positive. To investigate potential cross reactivity with related viruses, 45 sera from 2012/2013 that were positive in SBV ELISA were analyzed in VNTs for Aino, Akabane, Douglas, Peaton, Sabo, SBV, Sathuperi, Shamonda, Simbu and Tinaroo viruses. All 45 sera were positive for one or more of these viruses. Twenty-nine sera (64.4 %) were positive for SBV, and one had the highest titer for this virus. Conclusions: This is the first indication that Aino, Akabane, Douglas, Peaton, Sabo, SBV, Sathuperi, Shamonda and Tinaroo viruses circulate and cause negative effect on reproductive performance in cattle in Tanzania. SBV or a closely related virus was present before the European epidemic. However, potential cross reactivity complicates the interpretation of serological studies in areas where several related viruses may circulate. Virus isolation and molecular characterization in cattle and/or vectors is recommended to further identify the viruses circulating in this region. However, isolation in cattle is difficult due to short viremic period of 2 to 6 days, and isolation in vectors does not necessarily reflect the situation in cattle.
Intraperitoneal administration of butyrate prevents the severity of acetic acid colitis in rats
(Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), 2015) Malago, J. J.; Sangu, C. L.
Intrarectal infusion of butyrate improves colorectal disorders including ulcerative colitis (UC). However, it is not established whether systemically administered butyrate benefits such patients. The current study aimed at exploring and comparing the potential of intraperitoneally, intrarectally, and orally administered butyrate against acetic acid (AA)-induced UC in rats. Intrarectal administration of 2 ml of 50% AA was done after or without prior treatment of rats for 7 consecutive days with 100 mg/kg sodium butyrate (SB) intraperitoneally, intrarectally, or orally. Rats were sacrificed after 48 h of AA-treatment. Subsequently, colon sections were processed routinely for histopathological examination. We clinically observed diarrhea, loose stools, and hemoccult-positive stools, and histologically, epithelial loss and ulceration, crypt damage, goblet cell depletion, hemorrhage, and mucosal infiltration of inflammatory cells. The changes were significantly reduced by intraperitoneal, intrarectal, or oral butyrate, with intraperitoneal butyrate exhibiting the highest potency. It is concluded that intraperitoneal administration of butyrate abrogates the lesions of AA-induced UC and its potency surpasses that of intrarectal or oral butyrate.
Immunohistochemical detection of Mycoplasma mucoid mucoid small colony type in lungs of slaughtered cattle at Morogoro slaughterhouse, Tanzania
(Tanzania Veterinary Journal, 2015) Malago, J. J.; Mlay, J. D.
Diagnosis of contagious bovine pleuropneumonia (CBPP) in carrier animals remains to be a challenge in developing countries partly because of lack of diagnostic tools that can detect asymptomatic animals. As a result many apparently healthy animals pose a potential impending epidemic in periods of stress. We examined condemned lungs with CBPP-like lesions from apparently healthy slaughtered animals to confirm presence of the disease in these animals. A total of 13 lungs collected at abattoir were examined immunohistochemically using 3H12 and 6E3 monoclonal antibodies against Mycoplasma mycoides mycoides (MmmSC), the causative agent of CBPP. Both 3H12 and 6E3 antibodies detected the MmmSC antigens in all the 13 lungs in bronchial, bronchiolar and alveolar epithelia, bronchial glands, bronchial cartilage, and in alveoli. We conclude that CBPP is still present in various places of Tanzania, posing a threat to livestock production and that immunohistochemistry can be an efficient diagnostic method to confirm presence of the disease in asymptomatic healthy animals passed for slaughter.
Contribution of microbiota to the innate and acquired gut immunity during health and disease
(Nova Science Publishers, Inc., 2015) Malago, J. J.
The large number of microbials in the intestine that overrides the total human cells by ten folds alludes to significant contribution of the microbiota to human health. This is vivid in enteric and some systemic diseases emanating from disruption of the microbiota. The microbiota influences the development and functioning of both, innate and acquired immune systems for gut health. The effect of microbiota spills throughout the various components of the gut immune systems from “primitive” non specific pattern recognition receptors (PRR) to most specific adaptive T cell responses. To induce immune responses, commensal microbes are recognized by PRRs, which in turn regulate mucosal innate immunity and inflammatory responses. PRRs detect microbe-associated molecular patterns (MAMPs or "infectious non-self") or endogenous "danger signals" derived from stressed, damaged or infected tissue to stimulate the intestinal innate immunity that initiates adaptive immune responses. MAMPs include peptidoglycans, lipoproteins, lipopolysaccharides, teichoic acids, CpG DNA motif, double strand RNA and flagellin. In a balanced microbiota profile, PRR signaling ensures immune homeostasis and protects the host against enteral pathogens. Chapter one of this book will discuss the influence of the microbiota to PRR signaling during health and disease for intestinal immunity. Chapter two of the book focuses on a second level of innate immune system. This involves cells of the innate immune system that are responsible for driving non-specific innate immunity. They include natural killer cells, mast cells, eosinophils, basophils and the phagocytic cells including macrophages, neutrophils and dendritic cells. However, owing to the great commitment of macrophages and dendritic cells, a separate chapter for these two phagocytic cell types is allocated. Thus chapter two discusses the influence of microbiota on innate cells engendering intestinal immunity under health and disease. It concludes the innate immune system of the intestine. Macrophages and dendritic cells are professional antigen presenting cells. They sample antigens from the intestinal lumen, process, and present them to cells of the adaptive immune system. Despite of enormous types of enteral antigens ranging from harmful to beneficial, the antigen presenting cells are capable of efficiently discriminating them and driving respective responses to effector cells of the adaptive immune system. While dendritic cells are capable of priming T cell responses, macrophages do polarize the responses. As to how the microbiota influences the functioning of these cells, chapter three is devoted to discuss that phenomenon. The chapter links innate and adaptive intestinal immune systems since macrophages and dendritic cells lie in the interface between innate and adaptive immune systems. The acquired or adaptive immunity of the gut is split in humoral and cellular components. The humoral immune system is mainly geared by gut-associated lymphoid tissue (GALT) whose components include effector (i.e. epithelial lymphocytes and lamina propria) and inductive (i.e. mesenteric lymph nodes, Peyer’s patches, isolated lymphoid follicles, and cryptopatches) sites. It is interesting to note that microbiota influences GALT development and functioning during health and diseases. In germ free animals and those with disrupted microbita, GALT functioning is heavily compromised leading to diseases. Restoration of normal microbiotal profile to such individuals cures the disorders. Chapter four of this book will describe how the microbiota interacts with GALT and other components of the humoral immune system to maintain intestinal immunity under health and disease. The last chapter, chapter 5, focuses on the second part of the adaptive immune system which is cellular immune system. This system is dominated by several CD4 and CD8 lymphocytes that drive the cellular adaptive immune system. The main components are CD4+ cells which include T helper and regulatory T cells. Other T cells include cytotoxic T, memory, natural killer, and mucosa associated invariant T cells. While T helper cells drive most of the inflammatory responses, regulatory T cells downregulate these responses. As such, they are considered potential therapeutic agents of the future. Current knowledge indicates that the functioning of most, if not all, T cells is influenced by the microbiota. Chapter 5 is therefore devoted to discuss how the microbiota interacts with T cells during health and disease to foster intestinal immunity. In the past few years we have encountered mounting evidence showing that the microbiota plays essential role in regulating and maintaining host’s intestinal immunity. This is done through various ways including; regulation of mucin gene expression by goblet cells, modification of glycosylation of mucus to interfere with bacterial adhesion, colonization and invasion, induction of secretion of antimicrobial peptides by intestinal Paneth cells, regulation of alterations of intestinal permeability caused by infection, stress, and inflammation, and influences on development of mucosal and systemic immunity. It is becoming well comprehended that microbiota is pivotal to the intestinal immunity through crosstalk with the epithelium, immune cells and the immune system in general. Disruption of microbiota balance often leads to disease. This book explores recent findings on how microbiota influences the intestinal immune responses, both innate and adaptive, to foster the intestinal mucosal immunity. The insight gained could contribute to designing approaches suitable for treating gastrointestinal diseases caused by disruption of the microbiota.

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