Animal Diseases Commons^™

Prospects For Developing Odour Baits To Control Glossina Fuscipes Spp., The Major Vector Of Human African Trypanosomiasis, Maurice O. Omolo, Ahmed Hassanali, Serge Mpiana, Johan Esterhuizen, Jenny Lindh, Mike J. Lehane, Philippe Solano, Jean Baptiste Rayaisse, Glyn A. Vale, Steve J. Torr, Inaki Tirados

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We are attempting to develop cost-effective control methods for the important vector of sleeping sickness, Glossina fuscipes spp. Responses of the tsetse flies Glossina fuscipes fuscipes (in Kenya) and G. f. quanzensis (in Democratic Republic of Congo) to natural host odours are reported. Arrangements of electric nets were used to assess the effect of cattle-, human- and pig-odour on (1) the numbers of tsetse attracted to the odour source and (2) the proportion of flies that landed on a black target (1 × 1 m). In addition responses to monitor lizard (Varanus niloticus) were assessed in Kenya. The effects of …

Trypanosoma Brucei Rhodesiense Transmitted By A Single Tsetse Fly Bite In Vervet Monkeys As A Model Of Human African Trypanosomiasis, John K. Thuita, John M. Kagira, David Mwangangi, Enock Matovu, C. M.R. Turner, Daniel Masiga

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We have investigated the pathogenicity of tsetse (Glossina pollidipes)-transmitted cloned strains of Trypanosoma brucei rhodesiense in velvet monkeys. Tsetse files were confirmed to have mature trypanosome infections by xenodiagnosis, after which nine monkeys were infected via the bite of a single infected fly. Chancres developed in five of the nine (55.6%) monkeys within 4 to 8 days post infection (dpi). All nine individuals were successfully infected, with a median pre-patent period of 4 (range = 4-10) days, indicating that trypanosomes migrated from the site of fly bite to the systemic circulation rapidly and independently of the development of the chancre. …

Eco-Social Analysis Of An East African Agro-Pastoral System: Management Of Tsetse And Bovine Trypanosomiasis, Johann Baumgärtner, Gianni Gilioli, Getachew Tikubet, Andrew Paul Gutierrez

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A key constraint for development of many East African agro-pastoral communities is African animal trypanosomiasis or nagana caused by Trypanosoma spp. and vectored by species of tsetse flies (Glossina spp.). Suppression of trypanosomiasis through trapping of tsetse fly populations was conducted from 1995 to 2005 at and near Luke, Southwest Ethiopia. Odor baited mass trapping technology was used to suppress adult fly populations to very low levels while tryponocidal drugs were used to treat trypanosome infections in cattle. Data on ecological, economic and social variables were collected and analyzed in the context of eco-social dynamics in the community. The bio-economic …

The Glossina Proteolytic Lectin (Gpl) Gene Is Expressed Only In Members Of Glossina Species, M. W. Burugu, B. N. Mbatia, E. O. Osir, E. U. Kenya, L. U. Abubakar

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Differentiation of bloodstream-form trypanosomes into procyclics in tsetse flies (Diptera: Glossinidae) is a crucial step in the establishment of midgut infections. A number of factors have been implicated in the transformation process, including enzymes and lectins or lectin-like molecules. Recently, Glossina proteolytic lectin (Gpl) gene, which encodes a protein with both lectin and trypsin activities has been shown to stimulate transformation of bloodstream-form trypanosomes into procyclics in vitro. Using RT-PCR, we show that the induction of Gpl gene expression by blood meal occurs only in Glossina fuscipes fuscipes Newstead, Glossina austeni Newstead, Glossina pallidipes Austen, and not in the Anopheles …

Livestock Farmers' Perception And Epidemiology Of Bovine Trypanosomosis In Kwale District, Kenya, S. O. Ohaga, E. D. Kokwaro, I. O. Ndiege, A. Hassanali, R. K. Saini

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We did cross-sectional surveys in Kwale District, Kenya to determine the epidemiology of bovine trypanosomosis and livestock owners' perceptions of the disease. The surveys involved relative importance of trypanosomosis, examination of the current disease constraints, current control practices and drug-use patterns. Informal meetings were held with farmers and cattle census undertaken. Tsetse-fly densities and trypanosomosis prevalences in cattle were determined. A total of 132 farmers were interviewed. Trypanosomosis, anaplasmosis, East Coast fever, foot-and-mouth diseases were reported to be the major constraints to livestock production. Trypanosomosis was the most important compared to other diseases. Chemotherapy was the most widely used method …

Molecular Characterization Of A Tsetse Fly Midgut Proteolytic Lectin That Mediates Differentiation Of African Trypanosomes, Laila U. Abubakar, Wallace D. Bulimo, Francis J. Mulaa, Ellie O. Osir

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Differentiation of bloodstream-form trypanosomes into procyclic (midgut) forms is an important first step in the establishment of an infection within the tsetse fly. This complex process is mediated by a wide variety of factors, including those associated with the vector itself, the trypanosomes and the bloodmeal. As part of an on-going project in our laboratory, we recently isolated and characterized a bloodmeal-induced molecule with both lectin and trypsin activities from midguts of the tsetse fly, Glossina longipennis [Osir, E.O., Abubakar, L., Imbuga, M.O., 1995. Purification and characterization of a midgut lectin-trypsin complex from the tsetse fly, Glossina longipennis. Parasitol. Res. …

Evidence For The Involvement Of A Tsetse Midgut Lectin-Trypsin Complex In Differentiation Of Bloodstream-Form Trypanosomes, L. U. Abubakar, G. Zimba, C. Wells, F. Mulaa, E. O. Osir

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We have previously described a bloodmeal-induced molecule (lectin-trypsin complex) from the midgut of the tsetse fly, Glossina longipennis, with both lectin and trypsin activities (Osir et al., 1995). In this paper, we report on the isolation of a similar molecule from the midguts of Glossina fuscipes fuscipes and provide direct evidence for its involvement in the development of African trypanosomes. The molecule (native Mr ∼65,700) has two non-covalently linked subunits, Mr ∼28,800 and Mr ∼35,700. The native molecule was found to be capable of inducing differentiation of bloodstream-form trypanosomes into procyclic (midgut forms) in vitro. In the assays, specific antibodies …

Isolation Of Trypanosoma Brucei From The Monitor Lizard (Varanus Niloticus) In An Endemic Focus Of Rhodesian Sleeping Sickness In Kenya, Zipporah Njagu, Steve Mihok, Elizabeth Kokwaro, Didier Verloo

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Monitor lizards were sampled along the shores of Lake Victoria to detect natural infections of potentially human-infective trypanosomes. In an area with endemic rhodesian sleeping sickness, one of 19 lizards was infected (Busia, Kenya). Six of ten lizards also showed indirect evidence of infection with Trypanosoma brucei (antibody ELISA). In an area with no recent history of human disease (Rusinga Island), no parasites were found and no antibodies to T. brucei were detected. The isolate was identified as T. brucei through xenodiagnosis (completion of the life cycle in the salivary glands of tsetse), and through molecular techniques (positive reactions with …

Trypanosome Infection Rate In Cattle At Nguruman, Kenya, R. A. Tarimo-Nesbitt, T. K. Golder, R. D. Dransfield, M. F. Chaudhury, R. Brightwell

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Trypanosome infection rate in cattle at Nguruman was investigated in a study conducted in 1984-1986. Shifting pastoralism significantly reduced trypanosome infections in cattle. The cattle were more heavily infected with Trypanosoma congolense (16.5%) than Trypanosoma vivax (4.95%) and Trypanosoma brucei (0.19%). Trypanosoma theileri was observed only once among the cattle examined. Mixed trypanosome infections in cattle were observed to be 2.75% and 0.014% for T. congolense/T. vivax and T. congolense/T. brucei, respectively. The duration of infection in the cattle was 55 days for T. congolense and 79 days for T. vivax. High infections in cattle were observed 2 months after …

Dynamics Of Host Blood Effects In Glossina Morsitans Sspp. Infected With Trypanosoma Congolense And T. Brucei, Reardon O. Olubayo, Steve Mihok, Eli Munyoki, Leonard H. Otieno

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The pattern of infection in Glossina morsitans morsitans and G. m. centralis membrane-fed on eland, buffalo or goat blood mixed with Trypanosoma congolense or T. brucei was studied from day 1 to day 10. Tsetse were initially permissive vectors, with most flies harbouring infections of 104-105 parasites on day 3. However, after a second blood meal on day 3, flies cleared many infections with G. m. morsitans clearing more infections than G. m. centralis. Infective feeds of goat blood consistently increased final infection rates by limiting the number of infections lost between days 3 and 6. In further experiments with …

Detection Of Trypanosome Infections In The Saliva Of Tsetse Flies And Buffy-Coat Samples From Antigenaemic But Aparasitaemic Cattle, P. A.O. Majiwa, R. Thatthi, S. K. Moloo, J. H.P. Nyeko

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Relatively simple protocols employing non-radioactive DNA probes have been used for the detection of African trypano-somes in the blood of mammalian hosts and the saliva of live tsetse flies. In combination with the polymerase chain reaction (PCR), the protocols revealed trypanosomes in buffy-coat samples from antigenaemic but aparasitaemic cattle and in the saliva of live, infected tsetse flies. Furthermore, the protocols were used to demonstrate concurrent natural infections of single tsetse flies with different species of African trypanosomes. © 1994, Cambridge University Press. All rights reserved.

Isolation Of Trypanosoma Spp. From Wild Tsetse Flies Through Procyclic Expansion In Glossina Morsitans Centralis, Steve Mihok, Eli N. Munyoki, Freddie Masaninga, Paul N. Ndegwa, Reardon O. Olubayo

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Procyclic trypanosomes from wild tsetse flies were membrane-fed to Glossina morsitans centralis in order to develop an optimal technique for propagating field isolates. A 70% success rate was achieved in isolating Trypanosoma simiae and a variety of genotypes of T. congolense originating from G. pallidipes, G. brevipalpis and G. swynnertoni. Parasites matured into forms infective for mammals, and could be maintained by passage of gut forms to new groups of flies. In experiments with laboratory stocks, we also passaged immature gut infections of T. congolense and T. brucei from various tsetse species to G. m. centralis. The optimal technique was …

Trypanosoma Simiae In The White Rhinoceros (Ceratotherium Simum) And The Dromedary Camel (Camelus Dromedarius), Steve Mihok, Erich Zweygarth, Eli N. Munyoki, John Wambua, Richard Kock

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Trypanosoma simiae was identified as the cause of a disease outbreak in dromedary camels (Camelus dromedarius) introduced to Tsavo East National Park, confirming the susceptibility of camels to this pathogen. T. simiae was also isolated from a new host, the white rhinoceros (Ceratotherium simum) through xenodiagnosis with a susceptible tsetse species (Glossina morsitans centralis). A white rhinoceros showed some evidence of anaemia and lymphopaenia when harbouring T. simiae, but did not suffer any long-term health effects. © 1994.

Experimental Immunity Against Trypanosomiasis In Rabbits, Curtis Powell

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Rabbits were immunized with specially prepared subcellular fractions of a cloned Trypanosoma brucei brucei stock 427. One fraction was found to be highly immunoprophylactic in rabbits exposed to the vector fly genus Glossina m. morsitans (tsetse flies) infected with EATRO Trypanosoma brucei brucei 1969. The most immunoprotective fraction IPFA from T. b. brucei 427 gave 75% protection to animals challenged by EATRO T. b. brucei 1969. IPFA also showed the highest IgG antibody titre against the heterologous and homologous strains. In in vitro studies, the sera from these immunized rabbits killed different strains of parasites, T. b. brucei strains 1969 …

The Influence Of Host Blood On Infection Rates In Glossina Morsitans Sspp. Infected With Trypanosoma Congolense, T. Brucei And T. Simiae, S. Mihok, R. O. Olubayo, N. Darji, E. Zweygarth

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Trypanosoma congolense, T. brucei and T. simiae isolated from wild-caught Glossina pallidipes were fed to laboratory-reared G. morsitans centralis and G. m. morsitans to determine the effect of host blood at the time of the infective feed on infection rates. Bloodstream forms of trypanosomes were membrane-fed to flies either neat, or mixed with blood from cows, goats, pigs, buffalo, eland, waterbuck and oryx. The use of different bloods for the infective feed resulted in differences in infection rates that were repeatable for both tsetse subspecies and most parasite stocks. Goat, and to a lesser extent, pig blood facilitated infection, producing …

Inhibitory Effect Of Trypanosoma Brucei Brucei On Glossina Morsitans Midgut Trypsin In Vitro, M. O. Imbuga, E. O. Osir, V. L. Labongo

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The ability of Trypanosoma brucei brucei to inhibit trypsin or trypsin-like enzymes in crude midgut homogenates of Glossina morsitans morsitans was studied in vitro. The isolated parasites caused a concentration-dependent decrease in midgut trypsin activity. Furthermore, trypanosomes lysed by repeated freeze-thawing had a similar effect on trypsin activity. In both cases, the inhibition by either intact or lysed parasites was partial as revealed by Dixon plots. Similarly, trypanosome membrane proteins stoichiometrically inhibited trypsin activity, suggesting that the enzyme interacts specifically with a moiety on the parasite surface. The Km and Ki values obtained in this case were 35 μm and …

Trypanosome Infection Rates In Tsetse Flies (Diptera: Glossinidae) And Cattle During Tsetse Control Operations In The Kagera River Region Of Rwanda, Steve Mihok, Leonard H. Otieno, Christopher S. Tarimo

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Trypanosome infections were monitored in three species of tsetse fly (Glossina pallidipes Austen, G. morsitans centralis Machado, and G. brevipalpis News-tead) at four locations in the Kagera River region of Rwanda from May 1989 to September 1990. Two of the four areas (Mpanga Ranch and Bukora Ranch) were subjected to tsetse fly suppression operations with odour-baited traps. Proboscis infections of the Trypanosoma congolense and T. vivax types accounted for roughly equal numbers of the 207 mature infections detected (3.8%). Variation in infection rates was area-specific rather than tsetse species-specific. Order of magnitude differences in tsetse fly densities among areas were …

Studies On Tsetse Midgut Factors That Induce Differentiation Of Bloodstream Trypanosoma Brucei Brucei In Vitro, M. O. Imbuga, E. O. Osir, V. L. Labongo, N. Darji, L. H. Otieno

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An in vitro system for studying the transformation of bloodstream forms of Trypanosoma brucei brucei into procylic (midgut) forms is described. In this system, transformation of the parasites was stimulated by Glossina morsitans morsitans midgut homogenates at 27° C but not at 4° C. The transformation-stimulating capacity was irreversibly destroyed by heating the midgut homogenates at 60° C for 1 h. A correlation was established between the transformation activity of the midgut homogenates and trypsin activity. The protease inhibitors (soybean trypsin inhibitor and N-p-tosyl-l-lysine-chloromethyl-ketone) inhibited trypsin activity and completely blocked the transformation of the parasites. Furthermore, the midgut homogenates could …

Influence Of D(+)-Glucosamine On Infection Rates And Parasite Loads In Tsetse Flies (Glossina Spp.) Infected With Trypanosoma Brucei, Steve Mihok, Leonard H. Otieno, Nafisa Darji, David Munyinyi

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Teneral Glossina morsitans centralis, G. m. morsitans and G. pallidipes were infected with three different clones of Trypanosoma brucei in blood containing d(+)-glucosamine, an inhibitor of tsetse midgut lectin. On average, 5 days of d(+)-glucosamine treatment tripled infection rates, without affecting the proportion of infections that matured. Total infection rates were equal in males and females, but twice as many infections matured in males. Counts of parasites in the guts and salivary glands of 277 flies revealed order of magnitude differences among flies, with females consistently having 2-3-times as many parasites as males. Parasite numbers varied in a sex-specific manner …

Infection Rates In Glossina Morsitans Morsitans Fed On Waterbuck And Boran Cattle Infected With Trypanosoma Congolense, Steve Mihok, Reardon O. Olubayo, David F. Wesonga

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Teneral Glossina morsitans morsitans were fed on waterbuck (Kobus defassa) and Boran cattle (Bos indicus) infected experimentally with Trypanosoma congolense clone IL2895. Infection rates in tsetse varied from 9 to 31% when fed on cattle, and from 2 to 59% when fed on waterbuck. In waterbuck, infections were often detected through the development of parasites in tsetse at times when parasitaemia could not be detected through microscopic examination of blood. Male and female, and 1- and 2-day-old flies were equally susceptible to infection on both hosts. Infection in tsetse was associated with a 14% absolute reduction in survival during the …

Pathogenicity Of Tsetse-Transmitted Trypanosoma Congolense For Waterbuck (Kobus Defassa) And Boran Cattle (Bos Indicus), R. O. Olubayo, S. Mihok, D. F. Wesonga, E. R.M. Mbwabi

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Five waterbuck (Kobus defassa) and four Boran cattle (Bos indicus) were infected with Trypanosoma congolense IL2895 using Glossina morsitans morsitans. At the same time, two waterbuck and two cattle were inoculated intravenously with bloodstream forms. With both methods of challenge, cattle had short prepatent periods followed by a continuous high parasitaemia. All cattle became severely anaemic and had to be treated with trypanocidal drugs to prevent death. In contrast, tsetse and intravenous challenge of waterbuck resulted in a long prepatent period, followed by brief, intermittent levels of low parasitaemia, and eventual selfcure. Waterbuck did not become anaemic, even during short …

Ticks Affecting Animals In Australia, J Shilkin

Journal of the Department of Agriculture, Western Australia, Series 4

WHILE there are many external parasites affecting animals in Australia, information in regard to their geographical distribution and incidence is far from complete.

However, there is little doubt that the ticks, and in particular, the cattle tick, are the most important of these parasites in Australia.

We are fortunate that many species are not present in this country, as some of them are carriers of serious diseases of both man and animals.

The Gizzard Worm And Its Transmission To Chickens In Hawaii, Joseph E. Alicata

Harold W. Manter Laboratory of Parasitology: Library Materials

Gizzard-worms of poultry, Cheiloapirura hamulosa, are nematodes occurring in the gizzards of chickens and turkeys.

Summary and Conclusions

Previous to this report the carriers for the gizzard-worm in Hawaii were unknown. Recent investigations by the writer have shown that the flour beetle, Tenebroides nana, and the sand hopper, Orchestia platensis, collected from poultry farms in the Territory of Hawaii have been found naturally infested with the infective larvae of the poultry gizzard-worm, Cheilospirura hamulosa. Out of 8 laboratory-raised chickens to which there were fed about 2,300 grasshoppers that had been collected in an endemic gizzard-worm area, …