Department of Veterinary Pathology
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Item A 12- year retrospective study on pattern and relative frequency of preventable canine diseases in Morogoro(Tanzania Veterinary Journal, 2018) Raymond, R.; Matondo, A. B.A retrospective study was undertaken to determine the occurrence and relative frequency of canine cases admitted at the University Animal Hospital located at Sokoine University of Agriculture (SUA). The study involved examination of canine cases recorded for the past 12 years starting from 2005 to 2016. A total of 2,288 canine cases were evaluated and grouped based on disease condition matching with the hospital records. The top five most frequently admitted cases were found to be worm infestation (19%), parvo viral diarrhoea (15%), wound (13%), canine distemper (7.7%) and bacterial diarrhoea (7.6%). Worm infestation showed a high and steady occurrence; parvo viral diarrhoea and canine distemper cases were on the increasing trend whereas rabies and canine transmissible venereal tumour were on the decreasing trend. Interestingly, majority of cases reported were those which can be prevented through adequate veterinary care such as vaccination, routine deworming, and sanitation. The findings in this study call for further follow-up studies and re-assessment of the current strategies used in disease control in order to have a comprehensive understanding in the existing gaps which limit progress in the control of some diseases identified in this study.Item Atypical E2f functions are critical for pancreas polyploidization(PLOS ONE, 2018-01-12) Matondo, RB; Moreno, E; Toussaint, MJM; Tooten, PCJ; van Essen, SC; van Liere, EA; Youssef, SA; Bongiovanni, L; de Bruin, AThe presence of polyploid cells in the endocrine and exocrine pancreas has been reported for four decades. In rodents, pancreatic polyploidization is initiated after weaning and the number of polyploid cells increases with age. Surprisingly the molecular regulators and biological functions of polyploidization in the pancreas are still unknown. We discovered that atypical E2f activity is essential for polyploidization in the pancreas, using an inducible Cre/LoxP approach in new-born mice to delete biquitously the atypical E2f transcription factors, E2f7 and E2f8. In contrast to its critical role in embryonic survival, conditional deletion of both of both atypical E2fs in newborn mice had no impact on postnatal survival and mice lived until old age. However, deficiency of E2f7 or E2f8 alone was sufficient to suppress polyploidization in the pancreas and associated with only a minor decrease in blood serum levels of glucose, insulin, amylase and lipase under 4 hours starvation condition compared to wildtype littermates. In mice with fewer pancreatic polyploid cells that were fed ad libitum, no major impact on hormones or enzymes levels was observed. In summary, we identified atypical E2fs to be essential for polyploidization in the pancreas and discovered that postnatal induced loss of both atypical E2fs in many organs is compatible with life until old age.Item Bovine tuberculosis and brucellosis in livestock at the Greater Ruaha Ecosystem(The Tropical Veterinarian, 2020) Medardus, J. J.A cross-sectional study was conducted to determine the prevalence of bovine tuberculosis (BTB) and the seroprevalence of brucellosis in livestock at the Greater Ruaha Ecosystem in Tanzania. The study further characterized the Mycobacterium spp. from the slaughtered livestock. Survey conducted to assess potential herd-level risk factors for BTB and brucellosis revealed that the respondents’ ethnicity and herd mixing were the significant risk factors. Twenty-eight percent of 102 cattle herds had at least one positive or suspect BTB reactor. The overall prevalence of BTB infection in the cattle was 1.32% (18/1368). Forty-two percent of 93 flocks of the small ruminants had at least one brucellosis seropositive animal. The overall seroprevalence of brucellosis in the cattle and small ruminants was 6.6%. Although the prevalence of both diseases was relatively low for individual animals, herd-level prevalence was high, suggesting that infection is widespread in the study area and a significant number of households are at risk. Mycobacterium bovis strain identified via polymerase chain reaction (PCR) was confirmed by spoligotyping as spoligotype SB0133. This cattle strain of M. bovis was similar to previously reported involving wild animals in adjacent protected areas. Isolation of identical M. bovis from the wildlife and livestock and the demonstration of Brucella spp. seroprevalence in livestock in the same interface, strongly suggest livestock-wildlife interspecies sharing of these pathogens. Occurrence of the microorganisms poses a serious challenge to disease management strategies in pastoralist communities in the interface area.Item Case report: Suspected Piscine Chlamydia like infection in Tanzania(Tanzania Veterinary Journal, 2019) Matondo, A. B.; Mtalika, M. I.; Mdegela, R. H.Ten moribund fish were received at pathology laboratory to establish the cause of sponteneous mortalities of farmed tilapia recorded in Kilosa District, Morogoro region. Post-mortem examination revealed macroscopic mucous bands connecting gills and operculum; and oval to round grey-white cysts on the gill lamella. Gill samples were collected for microscopic and bacteriological investigation. Histopathological investigation revealed gill epithelial hyperplasia and characteristic enlargement of epithelial cells infected with pale and basophilic cytoplasmic inclusions. The gross pathological changes coupled with histopathological findings recorded in this case are typical features of epitheliocystis. Furthermore, fish mortalities ceased in the farm after water replacement and reconnection of all fish ponds with direct supply of fresh water from the source. This is the first report in Tanzania describing characteristic epitheliocystis lesions. Furthermore, this report re-affirm previous findings that epitheliocystis can be managed through routine management of water quality.Item Circulating Brucella species in wild animals of the Serengeti ecosystem, Tanzania(Springer, 2021) Sambu, R. M; Mathew, C; Nonga, H. E; Lukambagire, A. S; Yapi, R. B; Akoko, J; Fokou, G; Keyyu, J. D; Bonfoh, B; Kazwala, R. RBackground: Brucellosis is a bacterial zoonosis of public health and economic importance worldwide. It affects a number of domestic animals, wild animals and humans. Human brucellosis originates from either livestock or wildlife. The species of Brucella circulating in wild animals in Tanzania is largely unknown due to insufficient surveillance. This study was carried out to identify Brucella species found in selected wildlife hosts in the Serengeti ecosystem. Methodology: The study used a total of 189 archived samples that were obtained from cross-sectional studies previously conducted between 2000 and 2017 in the Serengeti ecosystem in Tanzania. Whole blood, serum and amniotic fluid collected from buffalos, lions, wildebeest, impala, zebra and hyena were available for DNA extraction. Multiplex polymerase chain reaction for B. abortus, B. melitensis, B. ovis and B. suis (AMOS PCR) and quantitative real time PCR (qPCR) targeting the bcsp31 and IS711 genes for Brucella genus detection and the IS711 targets alkB for B. abortus and BMEI1162 for B. melitensis were used to detect Brucella strains. Results: Out of the 189 samples tested, 12 (6.35 %) and 22 (11.6 %) were positive to AMOS-PCR and qPCR, respectively. Most of the positive samples were from lions (52.6 %) and buffaloes (19.6 %). Other animals that were positive included: wildebeest (13.6 %), impala (13.6 %), zebra (4.5 %) and hyena (4.5 %). Out of 22 positive samples, 16 (66.7 %) were identified as B. abortus and the other six samples did not amplify for neither B. abortus nor B. melitensis. Conclusions: The detection of Brucella DNA in archived wild animal samples shows testing potential of samples collected from this population. The zoonotic species B. abortus and B. melitensis detected in wild animals have previously been reported in livestock and humans in the region. The findings suggest that, due to the contact network, some of the identified wild animal hosts in this study could be reservoirs for infections in domestic animals and humans within the Serengeti ecosystem while others are likely dead-end hosts. One Health control strategies and continuous surveillance programs in other wildlife reserved areas should be implemented to help predicting transmission in livestock and humans in the region.Item 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.Item 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.Item 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.Item 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.Item Contribution of microbiota to the intestinal physicochemical barrier(Beneficial Microbes, 2015) Malago, J.J.The large number of intestinal microorganisms, which exceeds the total number of human cells by ten folds, alludes to a significant contribution to human health. This is vivid in enteric and some systemic diseases emanating from disruption of the microbiota. As life style keeps shifting towards disruption of the microbiota in most societies worldwide, interest in the contribution of the microbiota to gut health has grown enormously. Many studies have been conducted to elucidate the exact contribution of the microbiota to human health. The knowledge gained from these studies indicates that the microbiota interacts with the intestinal milieu to maintain gut health. In this review, the crosstalk of microbiota with the intestinal physicochemical barrier pivotal to the gut innate immunity is highlighted. In particular, the review focuses on the role of the microbiota on competitive exclusion of pathogens, intestinal pH, epithelial mechanical barrier integrity, apical actin cytoskeleton, antimicrobial peptides, and the mucus layer. Understanding this microbe-host relationship will provide useful insight into overcoming some diseases related to the disruption of the host microbiota.Item 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. JPorcine 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 …Item 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, AThe 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.Item 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.Item 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.Item 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, MBackground: 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.Item E2f8 mediates tumor suppression in postnatal liver development(The American Society for Clinical Investigation, 2016-08-01) Machiraju, Raghu; Kent, L. N.; Rakijas, J. B.; Pandit, S. K.; Westendorp, B.; Chen, H.; Huntington, J. T.; Tang, X.; Bae, S.; Srivastava, A.; Senapati, S.; Koivisto, C.; Martin, C. K.; Cuitino, M. C.; Perez, M.; Matondo, R. B.E2F-mediated transcriptional repression of cell cycle–dependent gene expression is critical for the control of cellular proliferation, survival, and development. E2F signaling also interacts with transcriptional programs that are downstream of genetic predictors for cancer development, including hepatocellular carcinoma (HCC). Here, we evaluated the function of the atypical repressor genes E2f7 and E2f8 in adult liver physiology. Using several loss-of-function alleles in mice, we determined that combined deletion of E2f7 and E2f8 in hepatocytes leads to HCC. Temporal-specific ablation strategies revealed that E2f8’s tumor suppressor role is critical during the first 2 weeks of life, which correspond to a highly proliferative stage of postnatal liver development. Disruption of E2F8’s DNA binding activity phenocopied the effects of an E2f8 null allele and led to HCC. Finally, a profile of chromatin occupancy and gene expression in young and tumor-bearing mice identified a set of shared targets for E2F7 and E2F8 whose increased expression during early postnatal liver development is associated with HCC progression in mice. Increased expression of E2F8-specific target genes was also observed in human liver biopsies from HCC patients compared to healthy patients. In summary, these studies suggest that E2F8-mediated transcriptional repression is a critical tumor suppressor mechanism during postnatal liver developmentItem 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, HEA 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.Item Epidemiological investigation of Peste des petits ruminants in selected regions of Tanzania(Sokoine University of Agriculture, 2021) Kgotlele, TebogoPeste des petits ruminants (PPR), one of the most economically important disease of small ruminants has been earmarked for eradication following the successful global eradication of rinderpest. The disease is caused by peste des petits ruminants virus (PPRV). For eradication to be successful, the different PPR situations and contexts in each region and country must be well understood and reflected upon. In this study, the objective was to conduct an epidemiological assessment of the spread and persistency of PPR in selected areas of Tanzania with focus on distribution of antibodies to PPRV, PPRV genetic diversity and identification of practices by small stock farmers in response to this disease. The study was carried out using samples collected between 2013 to 2016. Sera samples were collected from clinically healthy sheep and goats for detection of antibodies to PPRV, together with blood, swabs and tissues for detection of the virus using molecular assays. A questionnaire was also administered in order to collect demographic characteristics, knowledge and practices relating to this disease from small ruminant farmers during sample collection. The overall true seroprevalences from samples collected in 2013 and 2015 was 27% (n = 3838) and for samples collected in 2016 was 30% (n = 328). Seroprevalences for samples collected in 2013, 2015 and 2016 show that the disease is continuing to spread in the country as seropositivity was observed in regions where previously no disease had been reported. Presence of the virus was found in samples collected in Morogoro and Arusha regions in 2016. Molecular characterization of the virus clustered them into two lineages, II and III. This confirmed presence of two lineages circulating in animals from the same herd, adding another dimension into the complexity of the disease in Tanzania. Other findings were confirmation of co-infections with Mycoplasma capricolum subspecies capripneumoniae, Pasteurella multocida and Capripoxvirus which cause similar clinical signs to PPR, complicating clinical diagnosis but emphasizing the importance of laboratory confirmation. Small ruminant farmers’ knowledge by regions on the disease occurrence was found to be high in Arusha region (northern Tanzania) and low in Morogoro region (eastern Tanzania), corresponding with the seroprevalences observed from samples collected in 2013, 2015 and 2016 in the said regions. Risk practices identified during outbreaks included trading of live animals, use of veterinary drugs and unattendance to sick animals. These risk practices could facilitate the spread of the disease in the country especially as the disease is transmitted through contact with infected animals. In conclusion, this study has revealed that PPR continues to spread within Tanzania as evidenced by antibodies to PPRV detected in areas that previously did not have the disease. Presence of two PPRV lineages shows the ability of lineages to co-circulate in an endemic area as well as in the presence of co-infections with other diseases in the local herd. Overall, there is poor knowledge by small ruminant farmers in the study areas that may be contributing to the spread of PPR. It is therefore recommended that annual vaccinations be carried out after well designed participatory surveillances are conducted to improve the herd immunity to levels that can contain the spread of PPR as a control measure. These vaccinations should take into consideration the geographical distribution of PPR in Tanzania so as to create buffer zones to stop further spread to areas with low or no disease, within and in neighboring countries. Genetic diversity of the virus strains circulating in the country should be further investigated by whole genome sequencing and how they compare to other strains. To prioritize on small ruminant farmer’s knowledge on the disease and emphasize how their participatory disease surveillance can help with the ultimate goal of eradicating PPR in Tanzania, regionally and globally.Item Epidemiology and host genetic factors associated with bancroftian filariasis in endemic communities of North eastern Tanzania(Sokoine University of Agriculture, 2017) Mshana, H. J.Tanzania started a countrywide lymphatic filariasis elimination programme in 2000 adopting the mass drug administration (MDA) strategy. The drugs used for the MDA programme are a combination of ivermectin and albendazole. Clinically, the initial stages of lymphatic filariasis present as an acute febrile conditions with adenolymphangitis (ADL). Later on the disease is characterized by development of scrotal swelling (hydrocele) and swelling of the legs (lymphoedema) which gradually lead to elephantoid oedema. There is limited information on the current epidemiological trend of infections in areas where MDA implementation is ongoing and the immunological markers for early diagnosis of the disease have not been identified. The present study aimed at assessing the current status of bancroftian filariasis infection rate and morbidity in areas where MDA has been administered for over eight rounds as well as the clinical disease presentation and possible human genetic factors associated with disease development. The study was a cross-sectional descriptive study involving 472 individuals (>18 years) from endemic communities in Tanga region in north-eastern Tanzania where MDA has been implemented. Clinical data, socio-demographic survey and circulating filarial antigen (CFA) test was conducted using questionnaire and immuno chromatographic card test according to the manufacturer’s instructions respectively. A total of 76 individuals were tested for the presence or absence of a 23 nucleotide deletion within the 5’ untranslated region of toll like receptor 2 using allele specific real time -polymerase chain reaction (qPCR). A total of 472 individuals were screened: 307/472 (65.1%) of which were males while 165/472 (34.9%) were females. Of those, 272 were recruited for the study of which 87.86% were males and 12.14% were females. The proportion of CFA was 5.51%, that of hydrocoele was 73.2%, and that of lymphoedema was 16.0%. The proportion of hydrocoele combined with lymphoedema was 5.5%. The proportion of individuals with deletions in their toll like receptor 2 gene was 36.7 %. However, the presence of this deletion within the the TLR 2 gene was not statistically significantly associated with clinical outcome of the disease (P0.05). Our findings demonstrate a considerable low burden in filarial infection. However, there is clear evidence of ongoing transmission despite the 8 rounds of MDA. It is unlikely that the annual MDA would eliminate filarial transmission. The evidence of the presence of TLR 2 deletion genotypes in the 5’ untranslated region was found in individuals who reside in the endemic villages of Tanga region, North Eastern Tanzania, highlighting the potential for the susceptibility of bancroftian filariasis infection. These findings should inform the design of additional strategies to accelerate lymphatic filariasis control and elimination.Item Evaluation of baobab seed cake based diets for growth performance and carcass quality of pig in central zone, Tanzania(AJOL, 2021) Magonka, J. M.; Komwihangilo, D. M.; Malago, J.This study was carried out in Central Tanzania and aimed at evaluating the effect of Baobab seed cake (BSC) on growth performance and carcass quality of pigs. Twenty-four (24) weaners of both sexes were involved in the study which lasted for 84 days. Four diets were formulated with BSC replacing sunflower seed cake at four levels of 0, 7, 14 and 21% and allotted to four dietary treatments T1, T2, T3 and T4 respectively, in a completely randomized design. Results showed that the four levels of replacement had no significant effect on body weight gains although T2 outperformed the others in terms of weight gain with 23.19kg whereby T1 (20.54kg) and T3 (20.21kg) had almost similar weights and T4 had the lowest weight gain (15.52kg). The cost of production, carcass weights, and dressing percentages varied significantly (P≤ 0.05) whereby costs of production (in Tshs) were 151,643.28, 162,965.52, 150,820.03 and 117,646.74 for T1, T2, T3 and T4 respectively. Carcass weight and dressing percentages were 23kg, 20.5kg, 18.50kg, 9.50kgs and 55.4, 53.9, 51.4 and 48.7% for T1, T2, T3 and T4 respectively. Histopathology analyses of the carcasses indicated that there were no any detrimental changes resulting from an inclusion of BSC in pig diets thus the pork was fit for human consumption.
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