College of Veterinary and Medical Sciences

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Epidemiology and control of bovine fasciolosis and schistosomosis in the Southern highlands of Tanzania
(Sokoine University of Agriculture., 201) Makundi, Asanteli Eliangikundi
The main purpose of this study was to determine if anthelmintic treatment of early patent primary fasciolosis and schistosomosis would prevent development of acute disease and would improve productivity of calves which continue grazing high potential natural transmission areas, without causing unwanted side effects or interfering with the development of immunity. Aspects of transmission biology and host parasite relationship were also investigated. Field studies, including cattle and snails, were performed at Lulanzi dairy farm where the trematode infections were highly prevalent. In addition experimental Schistosoma bovis infections were carried out in confined calves. The results from snail studies showed that Bulinus natalensis was the most abundant freshwater snail, which was responsible for the transmission of Schistosoma bovis mainly towards the end ofthe rainy season. Results ofthe field study, where cattle were naturally exposed, showed that acquisition of trematode infections was gradual. It took five months for the peak egg excretion to be reached, followed by a gradual decline to a very low level. Both triclabendazole and praziquantel drugs were highly efficacious and reduced Fasciola and Schistosoma worms by 100% and 95.6% respectively; while for S. bovis faecal and tissue eggs the reduction was 98.9% and 79-96%, respectively. Treatment kept the faecal egg excretion of both parasites species at a very low level for more than seven months and did not affect the development of immunity. Deterioration of the body weights pathological lesions, mainly fibrosis of the liver, were observed in the treated experimentally infected animals than in the untreated ones. However, no clinical and haematological parameters were only seen during the dry season and it was more severe in the untreated compared to the treated, challenged calves. More severe iii signs were associated with such changes and there was a gradual resolution of the pathological lesions. In the experimental S. bovis infections it was shown that, along the small intestine, eggs were mainly deposited in the anterior part at week seven, in the central part at week 18 and evenly distributed at week 32 post infection. The key findings from the present study are that B. natalensis for the first time was proved to transmit S. bovis and that such an infection occurred in the snails that had an existing amphistome infection. The animal studies have demonstrated that natural Fasciola and Schistososma infections in cattle are mainly sub-clinical and their impact is seen mainly during the dry season when feed supply is limited. Although treatment of early infections transiently causes additional liver fibrosis, treatment prevents development of acute disease and does not interfere with the development of immunity. Furthermore, treatment prevents further deterioration of the health of the cattle during the dry period. In addition, the observed reduction in faecal egg excretion has an epidemiological impact of reducing the transmission of these infections. In general, the present findings raise the possibility of strategic use of anthelmintics for preventing the development of acute trematode disease in young ruminants, improving their productivity and reducing the transmission intensity in endemic areas
Dose-response relationships in a microneutralization test for foot-and-mouth disease viruses
(1977-05) Booth, J. C; Rweyemamu, M. M; Pay, T. W. F
Two-dimensional quantal microneutralization tests on foot-and-mouth disease viruses, in which neutralizing antibody activity was titrated against a serial range of virus doses, demonstrated a variety of dose-response curves some of which were rectilinear, others clearly curvilinear. Moreover, in the case of the non-linear responses obtained with some antisera, the shape of the curve was such that antibody titres recorded with doses of virus ranging from lCP-lO 5 TCD50 were closely similar. Studies were carried out on the effect of varying the con- ditions of the test on the shape of the dose-response curve: significant differences were obtained after treatment of the antiserum-virus mixtures with anti-species globulin, and when the test was assayed in cells of differing susceptibility to infection.
Microneutralization tests for serological typing and subtyping of foot-and-mouth disease virus strains
(1977-12) Rweyemamu, M. M; Booth, J. C; Head, Morwen; Pay, T. W. F
A microneutralization test for serotyping of FMD viruses is described. It is based on earlier observations by Booth, Rweyemamu & Pay (1978) that dose-response relationships in quantal microneutralizations often deviated from linearity. The typing test described therefore utilizes undiluted virus preparations. In about 90 % of samples a positive typing was obtained in contrast with about 50 % for the complement fixation test. The test was also found to be susceptible to minimal quantities of heterotypic viral contamination. For strain differentiation the microneutralization test was carried out as a checkerboard test. When compared with the complement fixation test it was found to be more specific. The necessity to utilize virus-neutralization test systems for comparing FMD virus strains particularly for the purpose of vaccine selection is emphasized. The two dimensional microneutralization test has been applied to a study of comparing FMDV vaccine strains for Europe, South America, the Middle East and East Africa.
Community response to malaria: Muheza district Tanzania 1983-1984 . A study in cultural adaptation
(1986) Fivawo, Margaret
This study of a rural community in the malaria endemic area of Muheza in Tanzania deals with several issues. (1) Malaria as a health problem is looked at from its ecological epidemiological context. It is seen as a problem which has made it necessary for the resident people to develop knowledge and ways of dealing with it. adaptation to a known hazardous environment. This is the people's (2) The resident people are considered in a historical and cultural context including their early contact with outside cultures. Their closeness to the Indian Ocean made it possible for them to develop early contact with Islamic Arab culture and others that followed later. Missionary contact came early as well and was followed by other Europeans who started the development of sisal, tea anc/ coffee plantations. As a result of this cultural contact, the resident peoples of Muheza developed new adaptive ways of managing malaria. Hence, today, a combination of methods are used to handle malaria and other diseases of the environment. (3) Even though Chloroquine and other Western medicines are popularly used, traditional medicines are also used in various combinations. djins and ancestors. Disease etiologies include parasites, This shows that traditional beliefs and values still strongly influence malaria management behavior even though otheriv factors are also present. The institution of the African extended family, which is based on ancestor kinship linkage, has strong influence on malaria management behavior. (4) The Fishbein behavioral model and theory of reasoned action serve to point out and explain the underlying processes behind the pragmatic observed behavior regarding the use of chloroquine in the management of malaria. (5) Problems in the health services are pointed out and suggestions are made on the direction of change needed to achieve improved management of malaria and other diseases.
Hematology and Glinical Chemistry in Goats
(Sokoine University of Agriculture, 1991) Mbassa, Gabriel
The initial objective of this work was to gather as much information on the hematological and clinical chemical reference values for goats. It was desired to present the work in easily readable tables and figures to facilitate comparisons and reference assessments. To achieve this objective it was thought natural, first to review the literature on the factors that affect the reference values and secondly to investigate the trends under the influence of some of the factors. On the second part studies were conducted on growth, environment and metabolic influence on the reference values. This thesis is based on these investigations. Data reported in conventional units were transformed into the International System of Units (SI) to enable comparisons from different sources. Although the contents of the thesis are far from the desired perfection of the objective, it is a pleasure to state that some parts of the original purposes have been accomplished. Credit for this part of the work goes to the Central Laboratory, Department of Clinical Studies, Royal Veterinary and Agricultural University, Frederiksberg and the financial sponsor, the Danish International Development Agency. I am very pleased to express my sincere thanks to Associate Professor Dirch Poulsen, Head of the Central Laboratory. I owe my deep gratitude for his interest in my research on hematological and clinical chemical reference values in goats, his continuous encouragement and allowing me free access to the facilities in the laboratory. I am indebted to Professor Prebcn Willeberg, Department of Animal Science and Animal Health for his fruitful and concentrated knowledge on experimen tal planning and data management via the supporting subject epidemiology. I am also indebted to Associate Pofessor Knud Christensen, Department of Animal Science and Animal Health for advice on statistical analysis of the results. I gratefully acknowledge Mr. Walther Kraul, Central Laboratory for his invaluable knowledge on the theoretical and practical use of computers and softwares in the laboratory. My deep gratitude is extended to Miss Emma Thomsen for her encourage ment, technical help in blood sample collections, careful and skillful work in analysis of the numerous parameters I requested for, which in most cases went beyond normal working hours. I am indebted to Associate Professor Jesper Monrad, Department of Veterinary Microbiology, Mr. Knud Larsen, Ms. Greta Schmedes, Jytte Anderson, Pia Jensen and Ingrid Dam for the offer of goats for blood samples in their herds in Denmark. I extend this gratitude to Dr. D. B. Mpiri, The Commissioner for Livestock Research, Ministry of Agriculture and Livestock Development Tanzania, for granting me permission to perform research at Malya Livestock Research Station, Mwanza, Tanzania. I would like to give my sincere thanks to Professor Sven Gade Christensen, Danida Project Coordinator, Faculty of Veterinary Medicine, Sokoine viUniversity of Agriculture, Morogoro, Drs. J. Msanga, J. Mukangi, M. Yongolo, Mr. Lugola, A. Masanja and other staff of The Veterinary Investigation Center, Mwanza and Malya Livestock Research Station for transport, laboratory facilities and technical assistance. It is impossible to list all my colleagues in the Department of Clinical Studies who assisted me in this project. I express my thanks to them all. I am obliged, however, to mention particularly Associate Professor Jens Ambjerg, Drs. Magishi Mgasa, Asger Lundorff Jensen, Falmer Hansen, Thomas Eriksen and Jens Madsen for their very useful discussions and comments on the manuscripts. I am very grateful to Lis Kjaer Jensen for translation of the thesis abstract into Danish and together with Anne Marie Norregird for secretarial assistance throughout my studies. I am happy to express my profound gratitude to Drs. Kaj Bruhn and Jorgen Henriksen of Research and Information Bureau. As a student of two Universities in a sandwich program, they offered me their sincere and friendly advice on my scholarship and provided solutions to problems that arose in the course of this program. I am also thankful to Mrs Mariane Boesen, the students adviser, Internation al Student Center and Mr. Sdren Clausen, the caretaker of my residential place at the Danida fellowship Center for offering me a very comfortable place that enabled me to concentrate fully on my studies. I am also very pleased to once again acknowledge the continuous support offered to this project by the Danish International Develop ment Agency, Ministry of Foreign Affairs, Copenhagen. Finally I wish to express my deepest gratitude to Anna, Leah, Patrick, Peter and John Mbassa (my family) for allowing me to fulfil my obligations and expectations in Denmark, to gain knowledge for development of Tanzanian people. They have been patient and accepted to endure difficulties due to my absence
Ultrastructural study of brain with experimental cowdria ruminantium infection (heartwater)
(1991) Mwamengele, George L. M.
Heartwater is an infectious, vector-borne, non-contagious disease of ruminants caused by Cowdria ruminantium. The etiologic agent is an obligate, intracellular parasite infecting phagocytic cells and, particularly, vascular endothelium. Transmission is effected by a three- host tick of the genus Amblyomma. Clinically, the disease is characterized by fever and signs of central nervous system disorder. There is general agreement on a deranged transport mechanism across the vascular wall as the basis for the development of morphologic lesions and clinical signs, but the actual mechanism of damage is poorly understood. Previous ultrastructural studies are few and have mainly been concerned with the parasite itself. The present morphologic study of the cerebral microvasculature is an attempt to elucidate the pathogenesis of the central nervous system changes. Five, clinically healthy, adult, Danish goats were used to establish the optimal procedure for perfusion fixation of the brain and, at the same time, to serve as normal controls. The animals were put under general anesthesia with pentobarbitone intravenously at 25 mg/kg and placed in dorsal recumbency. Following dissection of the ventral neck region intubation was performed and carotid arteries were isolated. Heparin (1250 i.u./kg) was injected and perfusion done through one of the carotid arteries using 3% phosphate-buffered glutaraldehy de solution at pH 7.4 and 500 mOsm. The best perfusion results were achieved with the tank placed 1.5 m above the heart. The brain was removed and 1 mm3 samples were diced from the best fixed areas of the cerebral and cerebellar cortices and further fixed i 3% glutaraldehyde solution. Some of the samples were routinely processed and stained for transmission electron microscopy. In an attempt to improve fixation and enhance demonstration of cellular membranes and other structures, other samples were subjected to alternative processing and staining regimes including reduced osmium tetroxide, ruthenium red, tannic acid, and uranyl block staining. On balance, however, these regimes did not produce entirely satisfactory results and were therefore omitted in the experimental studies. Corresponding pieces of brain tissue were post-fixed in 10% neutral, buffered formalin and routinely processed for light microscopy. A complete necropsy was performed and various tissues were taken and similarly processed for light microscopy. Fourteen Tanzanian blended goats were experimentally infected by intravenous inoculation with the Ball 3 strain of Cowdria ruminantium. Following an incubation period of about 2 weeks the animals developed temperatures up to 41.7°C. Other clinical signs included bleating, loss of appetite, loss of body condition, listlessness, abdominal respiration, stupor, head tremors and ataxia. In 2 goats, fits, opisthotonus, paddling movements and lateral recumbency were also observed. When temperatures started to drop the animals were killed and subjected to the same procedures as the controls. Necropsy revealed mild hydropericardium (2-13 ml) and splenomegaly in all 14 goats. Other, inconstant findings were urine retention in bladder, subepi- or subendocardial petechiae and flabbiness of the heart. In areas of incomplete perfusion leptomeninges appeared hyperemic. Light microscopically, Cowdria organisms were found in vascular endothelium of the brain in 8 goats. Focal perivascular mononuclear cell infiltrations, sometimes extending into the adjacent neuropil, were present in the brains of 12 animals. More extensive mononuclear cell infiltrations, occasionally with a few eosinophils, were in the leptomeninges of 11 goats. Focal mononuclear cell infiltrations were also found, although variably, in pulmonary and renal interstitium and in subepi- and subendocardial locations. All experimental animals ex hibited moderate hyperplasia of splenic lymphoid tissue. The only ultrastructural change of parasitized endothelial cells was compression and displacement of cytoplasm and organelles by membrane-bound colonies of Cowdria organisms. Perivascular accumulations of cells, consisting of macrophages, lymphocytes and occasional plasma cells, were invariably associated with non-parasitized segments of capillaries or venules. Often intravascular mononuclear cells were seen adhering to the endothelium with portions of their cytoplasm dipping into the endothelial cell membrane or interposed between the endothelial cell and the basement membrane. Large, spherical, electron-dense inclusions, often several in the same cell, were found in pericytes, both in control and experimental animals but with a notably higher incidence in the latter. Similar inclusions as well as smaller inclusions with the features of lipofuscin were seen in perivascular macrophages. An additional and unique type of cytoplasmic inclusion was encountered in perivascular macrophages. These inclusions presented as aggregations of irregularly round, membrane bound particles, 0.25-0.4 /zm in diameter, in some cases with an internal structure remini scent of partly degraded mitochondria. However, the aggregations were not convincingly enclosed within membranes as would be expected in case of autophagocytosis. Another, hypothetical, interpretation is that they represent abortive stages of Cowdria ruminantium attempting to develop extravascularly and that possibly cell-mediated immunity, developed during and after the incubation period, limits this second cycle within the host and results in the perivascular mononuclear cell infiltrations observed. The findings in this study suggest the possibility of a direct involvement of circulating monocytes in the pathogenesis of the brain lesions. Such cells may carry and shield the antigen through the vessel wall into extravascular sites since no signs of vasculitis or abnormal vascular permeability were found, making it unlikely that soluble antigens are involved. The finding of a morphologically intact endothelium and vessel wall, even under perfusion conditions, also casts doubt on a possible role of vasoactive substances in the development of the lesions. If and when permeability changes of the brain microvasculature occur, they apparently represent a later development of an inflammatory process rather than a primary mechanism in the pathogenesis of cerebral heartwater.
The role of management systems in the epidemiology of thermophilic campylobacters among poultry in eastern zone of Tanzania
(Epidemiology and infection, 1993) Kazwala, R. R.; Jiwa, S. F. H.; Nkya, A. E.
A total of 255 samnples of droppings collected from a total of 22 different poultry units were exainined for the presence of thermophilic campylobacters and the isolates biotyped using Skirrow's protocol. The organismTs were isolated from 90 (35*3 %) of all samples. Among the 22 units investigated, 13 (59 %) were found to have unsatisfactory management svstems, while 7 (32 %) and 2 (9 %) were found to have unsatisfactory and good systems respectively. Significantly large numbers of isolations, 68 of 147 (46 2 %), were made from samples collected from poultry units with poor management (P < 0 005). compared with 19 out of 84 (22 6%) samples which were collected from satisfactory units and 3 out of 24 (125%) samples collected from units exercising particularly good management. Nineteen of 72 (26-4%) samples collected from broilers, 32 out of 132 (24-2%) samples collected from layers and 39 out of 51 (76 49 %) samples collected from indigenous free range poultry were positive for campylobacters. Among the 90 strains isolated from various units, 64 (704 0 ) were Cnampylobacterjejuni, 25 (27-7 %) were C. coli, and only 1 (2 2 %) was C. laridis.
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
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 X 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. saginara (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. saginara 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. saginara 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.
Studies on the effects of trypanosoma congolense infection on the reproductive function of the ram
(University of Glasgow, 1993-12) Mutayoba, Benezeth Mugyabuso
This thesis describes a series of studies carried out in Scottish blackface rams experimentally infected with Trypanosoma congolense stabilates 57/10 and 57/11 (originally imported from ILRAD, Kenya as ILRAD 1180) with the primary aim of determining the effects of infection on the function of the hypothalamo-pituitary-gonadal axis. The studies also investigated the possibility that pyrexia is responsible for inducing gonadal endocrine and exocrine dysfunctions in infected animals. In addition the effect of infection on the function of the hypothalamo-pituitary-adrenal (HPA) axis was assessed in order to determine whether reproductive dysfunction generally seen during trypanosomiasis is related to stress caused by the infection. Chapter I comprises an introduction and a literature review on trypanosome- induced reproductive dysfunctions with emphasis on pyrexia and changes in the HPA axis. Chapter II describes the two experiments carried out in rams infected with T. congolense and the general materials and methods used in these studies. Chapter III describes the effects of infection on semen characteristics and pathology of various reproductive organs such as the testis, cauda epididymis, prostate and pituitary gland. It was found that T. congolense induced a progressive deterioration of semen quality in terms of an increased percentage of abnormal spermatozoa in the ejaculate. Progressive non-inflammatory degenerative changes were observed in the testis and prostate gland. The cauda epididymis showed varying degrees of decreased sperm reserve. Trypanosome-induced pyrexia led to an elevation of scrotal temperature in infected rams, suggesting that the changes in the gonads could have been due to increased testicular temperature. Indeed, similar changes were observed in the semen and gonads of uninfected rams following artificial elevation of testicular temperature by scrotal insulation. The pituitary gland showed changes associated with increased basophilic degranulation in infected rams. Changes in plasma concentrations of reproductive hormones in the same rams are described in Chapter IV. It was observed that soon after the onset of parasitaemia, which occurred within 1-2 weeks of infection, plasma testosterone concentration declined and levels remained low throughout the infection period. This reduction in plasma testosterone concentration was associated with a progressive and marked decline in testosterone pulse amplitude and testosterone secretion after injection of gonadotrophin-releasing hormone (GnRH) was also depressed throughout the infection period. By four weeks after infection, declining plasma testosterone concentration was accompanied by a significant increase in plasma luteinizing hormone (LH) pulse amplitude and increased pituitary responsiveness (LH secretion) to exogenous GnRH. As the infection progressed up to 8 weeks, the plasma LH concentration declined. This could not be associated with some aspects of gonadal steroid feedback as similar LH changes were observed in infected rams which had been castrated. Neither was the decline in plasma LH concentration caused by the inability of the pituitary gland to secrete and release LH as secretion of LH in response to exogenous GnRH was not impaired throughout the infection period. It was therefore concluded that the decline in plasma LH concentration after 8 weeks of infection was possibly induced by a progressive impairment of the ability of the hypothalamus to synthesize and/or release GnRH. Gonadal steroidogenesis in infected rams was investigated in the in vitro experiments described in Chapter V. This work showed that the alteration in plasma testosterone concentration following infection was associated with a decline in Leydig cell steroidogenesis, possibly mediated by increased testicular temperature affecting testosterone biosynthetic enzymes. However, by 4 weeks after infection, reduced plasma testosterone in infected animals was exacerbated by the impaired ability of the testes to release testosterone into the circulation resulting in a significant increase in intratesticular testosterone content. A similar increase was also observed in scrotal- insulated rams and it was therefore suggested that changes in intratesticular testosterone in infected rams at 4 weeks of infection was associated with a trypanosome-induced increase in testicular temperature perhaps through an effect on testicular blood flow. The effects of T. congolense infection on the function of the HPA axis in rams and the relationship between this and the changes in the hypothalamo-pituitary-gonadal axis are described in Chapter VI. The onset of parasitaemia stimulated a significant increase in plasma cortisol concentration which was followed within 3-6 week of infection by a decline in plasma cortisol levels and a reduced ability of the pituitary to secrete adrenocorticotrophin hormone (ACTH) after injection of corticotrophin-releasing hormone (CRH). Thereafter, the activity of the HPA axis was increased in step with the fluctuating parasitaemia. CRH stimulation of the HPA axis had no effect on LH secretion but reduced the plasma concentration of testosterone indicating the possible aggravation of T. congolense-induced reproductive disorders by stress-induced cortisol. The general discussion and conclusions drawn from all the experiments are. presented in Chapter VII. It can be concluded that T. congolense causes a very profound dysfunction of the hypothalamo-pituitary-gonadal axis in rams through actions at various sites. These effects may be partly associated with trypanosome-induced pyrexia and are exacerbated by increased plasma cortisol concentrations resulting from the activation of the HPA axis.
Urinary tract infection: The role of canine transmissible venereal tumour
(Wiley Online Library, 1996) Batamuzi, E. K.; Kristensen, F.
The role of transmissible ‘venereal tumours in the pathogenesis of urinary tract infection in dogs was investigated in 86 dogs. Fifty-five had transmissible venereal tumours, and the remaining 31 animals were used as controls. A thorough clinical examination of the external genitalia was carried out in each case. In the dogs with transmissible venereal tumours, the sites of attachment were recorded. Urine samples were taken by cystocentesis and the external genitalia swabbed; the samples were cultured for bacteria using standard methods. Tumours were found on the prepuce and other parts of the penis in male dogs; in bitches they were found in the vagina, vestibule or the vestibulovaginal junction. Dogs with transmissible venereal tumours were found to be at a high risk of having bacteriuria (odds ratio [OR] = 7.04). Obliteration of the urethral orifice by the tumour, possibly leading to urine retention, was thought to be the main reason for the high incidence of urinary tract infection among dogs with transmissible venereal tumours. Long-standing cases of transmissible venereal neoplasia had a higher chance of becoming bacteriuric compared with recent cases (OR=29.60). This study indicates that transmissible venereal tumour may he a predisposing factor for the development of urinary tract infection.
Urinalysis in companion animals : a urinary sediment, microbiology and protein study
(Sokoine University of Agriculture, 1996) Batamuzi, Emmanuel K.
This thesis is comprised of two parts, first is a general part which is an overview of the diagnostic methods for the diseases of the urinary system. The purpose of the general part is to bring together contemporary information about a whole range of diagnostic methods for diseases of the urinary system in companion animals.This section has been prepared for students, veterinary technicians and practitioners of veterinary medicine, who have not specialized in urology and nephrology, but whose work requires exposure with respect to available diagnostic techniques. The six papers listed below forms the second part. I: Batamuzi, E. K. and F. Kristensen : Diagnostic importance of urothelial cells of the dog and cat. Journal of Small Animal Practice 1995, 36: 17-21. II: Batamuzi, E. K., F. Kristensen, A. Basse and S. Dahl: Idiopathic renal hematuria in a dog. Veterinary Record 1994, 135: 603. in: Batamuzi, E. K. and F. Kristensen: Urinary tract infection: the role of canine transmissible venereal tumour. Journal of Small Animal Practice 1996 (In Press). IV: Batamuzi, E. K., F. Kristensen and A. L. Jensen : Analysis of serum proteins in geriatric dogs using agarose electrophoresis. J. Vet. Med. Series A. 1996 (In preparation). V: Batamuzi, E. K., F. Kristensen and A. L. Jensen : Subclinical glomerulopathy in selected cases of recurrent pyoderma in dogs. Veterinary Dermatology 1996 (In Press). VI: Batamuzi, E. K., F. Kristensen and A. L. Jensen : Composition of protein in urine from dogs with pyoderma. Veterinary Record 1996 (Submitted).
Prevalence of canine gastrointestinal parasites in Morogoro, Tanzania
(Taylor and Francis, 1996-07) Muhairwa, A. P; Mtambo, M. M.A; Kusiluka, L. J.M; Maeda, G. E; Kambarage, D. M; Makene, V. W
Out of 235 domestic dogs from Morogoro municipality and Mgeta area in Morogoro region coproscopically screened for gastrointestinal parasitic infections, 174 (74%) were found positive for one or the other parasite. Ancylostonza caninunz was the most common parasite (72%). Protozoan parasites and other helminths were less prevalent (4%). The prevalence of gastrointestinal parasitism was significantly higher (P<0.05) in dogs <6 months (prkppies) than in adults with no sex effect.
Intestinal protozoan parasites of pigs reared under different management systems in Morogoro, Tanzania
(Taylor and Francis, 1996-07) Muhairwa, A. P; Mtambo, M. M.A; Kambarage, D. M; Esrony, K; Kusiluka, L. J.M
Sixty three piggery units with a total herd size of 424 pigs i n the small-scale and semi-intensive management systents from semi arid and tropical highlund areas of Morogoro region were screened for intestinal protozoan parasites. Thirtysix percent of the screened animals were positive for eimeriosis and 7.8% for cryptosporidiosis. Prevalences of eimeriosis in the semi-intensive and sntall-scale management systems were 22% and 48%, respectively. High prevalences of eimeriosis and cryptosporidiosis (60% and 25%, respectively) were observed in the tropical highland climate area (Mgeta) and low rates (26% and 0.3%, respectively) were evident i n the semi-arid zone. Ninety five per cent of infected pigs excreted between 100 and 5000 OPG and five per cent were excreting more
Eimeriosis in dairy cattle farms in Morogoro municipality of Tanzania
(Elsevier Science B.V., 1996-10) Muhairwa, A.P; Chibunda, R.T; Kambarage, D.M; Mtambo, M.M.A; Kusiluka, L.J.M; Kazwala, R.R
Coccidial oocysts were detected in 35% of 445 cattle in four medium-scale and 20 small-scale dairy farms in Morogoro municipality, Tanzania. The highest prevalence (56%) was observed in animals aged between 5 and 18 months, whereas lower prevalences were observed in calves (29%) aged between 12 days and 4 months and adults (30%). No coccidial oocysts were detected in calves less than 12 days old. The oocyst output was high in calves, followed by weaners; adults had the lowest oocyst output. The number of oocysts per gram of faeces was significantly higher (P < 0.001) in diarrhoeic animals than in non-diarrhoeic animals, and more so in young calves. Eimeria species infecting the animals included Eimeria bovis (68%) and Eimeria zuemii (57%), Eimeria ellipsoidalis (25%), Eimeria cylindrica (23%), Eimeria aubumensis (22%), Eimeria alabamensis (12%) and Eimeria subspherica (5%). Mixed infections involving two or three species were common. Our findings indicate that eimeriosis is common in cattle in Morogoro municipality. Published by Elsevier Science B.V.
Manual on the preparation of national animal disease emergency preparedness plans
(FAO, 1996-11) Geering, William A; Roeder, Peter L; Obi, Timothy U; Rweyemamu, Mark M
The control and eradication of livestock diseases are primarily the responsibility of national governments whose executive for this purpose is the national veterinary service. Since its inception FAO has been actively involved in the control of livestock diseases and its Animal Health Service (AGAH) is dedicated to this purpose. Over the years AGAH, with the help of expert panels and technical assistance schemes, has played a key normative role in developing standards and policies for dealing with major diseases. The result has been progressive reorientation of veterinary services, education and research so as to ensure an integrated approach to major diseases, to the improvement of animal health and productivity and in the preparation of animal products. In this regard AGAH collaborates with other international and regional organizations, particularly the International Office of Epizootics (OIE), the World Health Organization (WHO), the International Atomic Energy Agency with which FAO has a Joint Division (FAO/IAEA), regional organizations such as the Pan-American Health Organization (PAHO) and the Inter-African Bureau for Animal Resources of the Organization of African Unity (OAU/IBAR), as well as with bilateral and multilateral donor agencies. A characteristic of transboundary animal diseases (TADs) is that they themselves can be the cause of national emergencies and, as this manual demonstrates, their significance often transcends national boundaries. They are of particular importance to food security and sustained economic development and trade for many countries. It is imperative therefore, wherever possible, to limit the socio-economic disruptions resulting from outbreaks of TADs. The role of FAO in the fight against epidemic diseases of livestock has recently been strengthened with the establishment of the special programme, Emergency Prevention System for Transboundary Animal and Plant Pests and Diseases (EMPRES). Furthermore, the World Food Summit, through Objective 3.1 of Commitment Three of the Rome Declaration on World Food Security and the Plan of Action, November 1996, commits governments, in partnership with all actors of civil society, and with the support of international institutions to “seek to secure effective prevention and progressive control of plant and animal pests and diseases, including especially those which are of transboundary nature, such as rinderpest, cattle tick, foot and mouth disease and desert locust, where outbreaks can cause major food shortages, destabilize markets and trigger trade measures; and promote concurrently, regional collaboration in plant pests and animal disease control and the widespread development and use of integrated pest management practices”. It should also be noted that the need for effective preparedness for and response to emergencies, including those caused by pests and diseases, is enshrined in Commitment Five of the World Food Summit Plan of Action, where Objective 5.2 states inter alia that international organizations will “maintain, promote and establish, as quickly as possible, in collaboration with non-governmental organizations and other organizations, as appropriate, the preparedness strategies and mechanisms agreed upon at the ICN, including development and application of climate forecast information for surveillance and early warning, drought, flood, other natural disasters, pest and disease alertness”. The Manual on the preparation of national animal disease emergency preparedness plans is thus both a book of reference for national veterinary services and a contribution of the EMPRES programme towards the fulfilment of a component of the World Food Summit Commitments.
Bovine tuberculosis in the lake Victoria zone of Tanzania and its possible consequences for human health in the HIV/AIDS era
(Veterinary Research Communications, 1997) Jiwa, S. F. H.; Kazwala, R. R.; Aboud, A. A. O.; Kalaye, A. J.
A total of 8190 cattle from 42 well-managed herds in the Lake Victoria zone of Tanzania were tested for bovine tuberculosis by a single comparative intradermal test (SCITT) using avian and bovine puri¢ed protein derivative (PPD) antigens. The prevalence of bovine tuberculosis in this area was found to be 0.2%. There was signi¢cant variation (p50.001) among the herds tested in the four regions in this zone (Kagera, Mara, Mwanza and Shinyanga). The highest prevalence (2.12%) was in a herd of 566 cattle which had recently arrived in Kagera region from Dar-es-Salaam. None of the 915 cattle tested in Shinyanga or of the 254 resident cattle in the Kagera region were positive by SCITT. This area, and particularly the Kagera region, has the highest human morbidity and mortality due to the acquired immunode¢ciency syndrome in Tanzania. Therefore, the presence of bovine tuberculosis in cattle necessitates further investigations on the role of animal-derived tuberculosis in human health.
Factors associated with diseases and mortality of calves in Morogoro, Tanzania
(Sokoine University of Agriculture, 1997) Mellau, Lesakit Sipira Bernard
This study was aimed at elucidating the influence of management and other factors associated with diseases and mortality of calves managed under intensive, semi intensive and free range systems practised by stale farms, parastatal farms and small scale dairy producers in the region. Management factors include bucket feeding versus suckling of colostrum, administration of post colostra! feeds, housing and disease control schemes. Other factors were breeds of cattle and season of the year. A total of 368 calves were involved in the study over a period covering one rain season and one dry season. 138 calves were from Kingolwira Prisons farm (KPF), 127 from Mlali, 57 from Azam Estate, 22 from Magadu dairy Unit and 24 from SUA farm. All these farms are within a radius of 50 kilometers from Morogoro town and were selected on the basis of differing management systems, herd size and access to the farm by road. The study was conducted through questionnaires, clinical examination and laboratory analysis for hematological, parasitological and pathological parameters. Prevalence of diarrhoea was significantly high in bucket fed calves than suckeld calves “(Pc0.001). Bovine coronavirus, rotavirus and Escherichia coli K 99 antigens were detected in 61% of faecal samples collected, and mixed infection of 2 or all of these organisms was frequent. Helminthosis was observed in both weaned and unweaned calves but calves less than 1 month old were relatively less affected as compared to older calves "(P <0.001). Haemonchus spp, Trichostnmgylus spp, Strongyloides papillosus, Oesophagostonium spp and Cooperia oncophora were the most frequently isolated worms, where they accounted for 35.5%, 15.5%, 15.5%, 31.1% and 2.2% respectively. Toxocara vindorum infestation was detected in only 4 calves of less than 28 days at Mlali farm where water buffaloes graze with cattle. Other diseases were, pneumonia, cutaneous mycosis which subsided with increasing age, bovine parasitic otitis, cases of Beta hemolytic E. coll otitis and alopecia of unknown cause. Mortality rate among calves was 25%, 17.4%, 13.6%, 8.7% and 7.8% for SUA farm, KPF, Magadu dairy unit, Azam Estate and Mlali farms respectively. Weaned and unweaned calf mortality contributed equally to total calf mortality. Helminthosis was the cause of mortality in weaned calves, whereas, pneumonia and diarrhoea were the main causes of death in unweaned calves. Coccidiosis was not a serious disease in calves managed under semi intensive and free range systems as it was in intensively managed calves.
Helminthosis in local and cross-bred pigs in the Morogoro region of Tanzania
(Elsevier, 1997-01) Muhairwa, A.P; Mtambo, M.M.A; Kambarage, D.M; Elsrony, K; Kusiluka, L. J. M
We investigated the prevalence, burden and types of gastro-intestinal helminths in 424 local and cross-bred pigs kept under different management systems in two climatic zones in the Morogoro region of Tanzania. Coprological examination revealed that 53% of the pigs excreted hehninth eggs in their faeces. The median eggs per gram of faeces (EPG) was 500 (range 100-22000). Local breeds in the Mgeta location with tropical highland climate showed signifi- cantly higher prevalence (P < 0.001) and median EPG values ( P < 0.001) than the cross-bred animals in the semi-arid area. There was no significant difference in the prevalence (P = 0.90) of helminth infection and egg outputs (P = 0.78) in cross-bred pigs raised under the small-scale and semi-mtensive management systems in the semi-arid zone. Piglets showed significantly lower prevalence of helminthosis (P < 0.001) than the weaners, growers and adults in both local and cross-bred animals. Median EPGs of growers and adult animals were significantly higher than those of piglets and weaners (P = 0.006). The prevalences of various hehninth species were Oesophagostomum sp. (40%), Ascaris suum (12%), Strongy loides ransomi (9% ) and Trichuris suis (St% ). 0 1997 Elsevier Science B.V.
Trypanosome non-specific antibody responses during trypanosoma congolense infection of cattle
(Sokoine University of Agriculture, 1998) Buza, Joram Josephat
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-vai&ci&d group were killed between 31-51 after infection and mononuclear cells prepared from spleen tissue. The cells were 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 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). number of non-trypanosome antigens such as B-galactosidase, ferritin and double-stained for CD5 using monoclonal antibody IL-A67 and surface 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. In the first experiment, IgM antibodies reacting with a number of unrelated nontrypanosome 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 to unrelated antigens due to presence of antibody molecules, each one capable of binding more than one unrelated antigens, such as the poly reactive antibodies secreted by murine and human CD5+ B cells. This experiment was initiated to investigate whether the trypanosome non-specific antibodies are polyclonal or poly reactive. 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 as observed in cases of polyclonal activation. The second one attribute reactivity pool was passed through immunoaffinity 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 only with trypanosome lysate but not with the non-trypanosome antigens. The trypanosome-specific IgG fraction was only found in post-infection sera. polyreactive. Their presence in pre-infection sera indicates that the infection does 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 sera. In contrast, the IgG fraction purified on trypanosome lysate column reacted These results conclude that trypanosome non-specific IgM antibodies are polyreactive. Their presence in pre-infection sera indicates that the infection does 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 sera. In contrast, the IgG fraction purified on trypanosome lysate column reacted These results conclude that trypanosome non-specific IgM antibodies are not specifically induce them, but helps to amplify their production. In contrast 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 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 antibody responses during trypanosome infections of cattle is not known. The aim antibody response during T. congolense infection of Boran cattle. of this experiment was to investigate the role played by CD4+ or CD8+ on various antigens released after the destruction of trypanosomes, and the 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 fl-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, nonspecific 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 T. congolense infection in susceptible Boran cattle. CD8 T cells have no effect onantibody responses to trypanosome infections in cattle.

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