African Animal Trypanosomosis Research Articles

Are integrated livestock disease-management practices complements or substitutes? The case of AAT control in rural Ethiopia

Livestock, particularly cattle, are an integral part of livelihoods in rural sub-Saharan Africa. However, diseases such as African animal trypanosomosis (AAT) have limited the potential of this important sector in the rural household economy. Using a representative sample of small-scale cattle farmers, this study investigates the adoption of modern AAT-management technologies in rural Ethiopia. Specifically, this study investigatesthe adoption of so-called ‘best-bet technologies’ (BBTs), recommended by veterinary experts as complementary measures to manage AAT. The results show that the multiple adoption of BBTs was low. In addition, BBTs were adopted as substitutes, and not as complements as suggested by veterinary experts. The results suggest budgetary constraints are proxied by wealth, and information asymmetry explains the substitution effects. The training and reeducation of veterinary personnel, as well as programmes and interventions that would improve access to livestock-management inputs, should be pursued vigorously by policy makers to increase the adoption of modern AAT-management technologies to improve cattle productivity.

In vitro cultivation of Trypanosoma congolense bloodstream forms: State of the art and advances

Animal African Trypanosomosis (AAT or Nagana) is a severe vector-borne disease caused by protozoan parasites belonging to the Trypanosomatidae family and is usually cyclically transmitted by blood-sucking tsetse flies. AAT remains a major problem in sub-Saharan Africa. Among the main AAT causative agents, Trypanosoma congolense (T. congolense or Tc) is one of the most important trypanosome species, in terms of economic and animal health impacts, infecting cattle and a wide range of animal hosts as well. To advance in AAT prevention and control, it is essential to better understand trypanosome biology and pathogenesis using bloodstream form (BSF) in vitro culture. The in vitro cultivation of T. congolense IL3000 BSF strain is already well established and widely used in research studies and drug activity assays. However, it may probably no longer truly reflect the reality of field trypanosome strains, due to decades of use and subsequent modifications. Here, we propose a novel culture protocol that supports the long-term in vitro growth of the animal-infective BSFs of three Savannah and Forest types of T. congolense strains, including T. congolense clone IL1180, which is not only a field strain but also a commonly-used reference strain in experimental animal assays. We established a homemade culture medium which made it possible to sustain T. congolense IL1180 growth from infected mouse blood for 18 days in axenic conditions. Moreover, we developed an efficient freezing/thawing system that allowed, for the first time, T. congolense IL1180 BSF growth within 30 days after thawing. Our results on T. congolense adaptation to in vitro culture are encouraging for future gene studies using new molecular tools or for new therapeutic drug assays.

Farmer perceptions and willingness to pay for novel livestock pest control technologies: A case of tsetse repellent collar in Kwale County in Kenya.

Tsetse-transmitted Animal African Trypanosomosis (AAT) is one of the most important constraints to livestock development in Africa. Use of trypanocides has been the most widespread approach for the management of AAT, despite the associated drug resistance and health concerns associated with drug metabolites in animal products. Alternative control measures that target tsetse fly vectors of AAT, though effective, have been hard to sustain in part because these are public goods applied area-wide. The International Centre of Insect Physiology and Ecology (icipe) and partners have developed and implemented a novel tsetse repellent collar (TRC) applied on animals to limit contact of tsetse flies and livestock, thereby reducing AAT transmission. The TRC has now advanced to commercialization. A household-level survey involving 632 cattle keeping households, was conducted in Shimba Hills region of Kwale County, where field trials of the TRC have been previously conducted to assess farmers' knowledge, perception, and practices towards the management of tsetse flies, their willingness to pay (WTP) for the TRC, and factors affecting the WTP. Almost all the respondents (90%) reported that tsetse flies were the leading cattle infesting pests in the area. About 22% of these correctly identified at least four AAT clinical signs, and even though many (68%) used trypanocidal drugs to manage the disease, 50% did not perceive the drug as being effective in AAT management (50%). Few respondents (8%) were aware of the harmful effects of trypanocidal drugs. About 89% of the respondents were aware of icipe TRC, and 30% of them were using the field trial collars during the survey. Sixty-three (63%) of them were willing to pay for the TRC at the same cost they spend treating an animal for AAT. On average farmers were willing to pay KES 3,352 per animal per year. Male educated household heads are likely to pay more for the TRC. Moreover, perceived high AAT prevalence and severity further increases the WTP. Wider dissemination and commercialization of the herd-level tsetse control approach (TRC) should be encouraged to impede AAT transmission and thus enhance food security and farm incomes among the affected rural communities. Besides the uptake of TRC can be enhanced through training, especially among women farmers.

Trypanosoma brucei Lipophosphoglycan Induces the Formation of Neutrophil Extracellular Traps and Reactive Oxygen Species Burst via Toll-Like Receptor 2, Toll-Like Receptor 4, and c-Jun N-Terminal Kinase Activation.

Trypanosoma brucei brucei is the causative agent of African animal trypanosomosis, which mainly parasitizes the blood of the host. Lipophosphoglycan (LPG), a polymer anchored to the surface of the parasites, activates the host immune response. In this study, we revealed that T. brucei LPG stimulated neutrophils to form neutrophil extracellular traps (NETs) and release the reactive oxygen species (ROS). We further analyzed the involvement of toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4) and explored the activation of signaling pathway enzymes in response to LPG stimulation. During the stimulation of neutrophils by LPG, the blockade using anti-TLR2 and anti-TLR4 antibodies reduced the phosphorylation of c-Jun N-terminal kinase (JNK), the release of DNA from the NETs, and the burst of ROS. Moreover, the addition of JNK inhibitor and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor exhibited similar effects. Our data suggest that T. brucei LPG activates the phosphorylation of JNK through TLR2 and TLR4 recognition, which causes the formation of NETs and the burst of ROS.

Anaemia Associated with Trypanosomes Infections in Cattle of West Gojjam Zone, Northwest Ethiopia

Background African animal trypanosomosis is a major veterinary problem over a large area of the tsetse belt region of Africa. Anaemia is a cardinal sign of trypanosome infections. The mechanism of anaemia due to trypanosomosis is complex and multifactorial in origin. Packed cell volume (PCV) usually gives an indication of the anaemia and disease status of a trypanosome-infected animal. Methods A cross-sectional study was conducted from December 2017 to January 2018 in West Gojjam zone, Northwest Ethiopia, to determine the trypanosome infections rate and the possible correlation between parasitic infection and anaemia using the dark ground buffy coat technique, Giemsa-stained thin blood smear, and PCV reading on a haematocrit reader. Results The overall trypanosomosis prevalence was 7.81%, 95% CI = 7.45–8.17. Trypanosoma congolense (4.25%) and T. vivax (3.56%) were the trypanosomes species identified in the studied area. PCV for all sampled cattle was analysed to estimate the degree of anaemia. From the total examined animals (N = 730), 356 (48.77%) were anaemic and 374 (51.23%) were nonanaemic. The mean PCV of parasitemic cattle was significantly lower (21.09%, 95% CI = 20.13–22.05) than that of aparasitemic ones (25.96%, 95% CI = 25.68–26.24). There was a positive association between trypanosome infection and anaemia. Although both trypanosome species are significantly associated with a decreased herd mean PCV (<24), the mean PCV of cattle infected with T. congolense (19.45%) was lower than that of infected with T. vivax (23.04%). The herd mean PCV was not significantly associated to locations, age, and sex of the studied animals. Conclusions The study confirms that the prevalence of trypanosomes infections and herd mean PCV has a significant association. The mean herd PCV can be a useful cheap tool to screen for possible trypanosome infection. However, there were cattle positive for trypanosomes having mean PCV within the reference interval and negative animals with anaemia. Furthermore, PCV reading should be confirmed by other diagnostic techniques to accurately conclude that trypanosomosis is the only cause of anaemia.

Interactions Between Tsetse Endosymbionts and Glossina pallidipes Salivary Gland Hypertrophy Virus in Glossina Hosts.

Tsetse flies are the sole cyclic vector for trypanosomosis, the causative agent for human African trypanosomosis or sleeping sickness and African animal trypanosomosis or nagana. Tsetse population control is the most efficient strategy for animal trypanosomosis control. Among all tsetse control methods, the Sterile Insect Technique (SIT) is one of the most powerful control tactics to suppress or eradicate tsetse flies. However, one of the challenges for the implementation of SIT is the mass production of target species. Tsetse flies have a highly regulated and defined microbial fauna composed of three bacterial symbionts (Wigglesworthia, Sodalis and Wolbachia) and a pathogenic Glossina pallidipes Salivary Gland Hypertrophy Virus (GpSGHV) which causes reproduction alterations such as testicular degeneration and ovarian abnormalities with reduced fertility and fecundity. Interactions between symbionts and GpSGHV might affect the performance of the insect host. In the present study, we assessed the possible impact of GpSGHV on the prevalence of tsetse endosymbionts under laboratory conditions to decipher the bidirectional interactions on six Glossina laboratory species. The results indicate that tsetse symbiont densities increased over time in tsetse colonies with no clear impact of the GpSGHV infection on symbionts density. However, a positive correlation between the GpSGHV and Sodalis density was observed in Glossina fuscipes species. In contrast, a negative correlation between the GpSGHV density and symbionts density was observed in the other taxa. It is worth noting that the lowest Wigglesworthia density was observed in G. pallidipes, the species which suffers most from GpSGHV infection. In conclusion, the interactions between GpSGHV infection and tsetse symbiont infections seems complicated and affected by the host and the infection density of the GpSGHV and tsetse symbionts.

Molecular Prevalence of Trypanosome Infections in Kachia Grazing Reserve of Kaduna State Nigeria

African Animal Trypanosomosis (AAT) is a major factor limiting livestock productivity in large areas of humid and subhumid Africa. Astudy was conducted to estimate the prevalence of Trypanosomiasisin sheep and goats from Laduga, Kachia grazing reserve area of Kaduna State. Blood samples (5 ml) were randomly collected by venepuncture of the jugular vein, from 21 goats and 21 sheep of both sexes. The 42 blood samples were first screened by wet mount and samples were later analyzed by nested polymerase chain reaction (PCR) using generic primers that amplified the internal transcribed spacer-1 (ITS-1) gene region of the 16S rRNAgene. Microscopic examination revealed only 2.4% prevalence for T. vivax and 0% for T. brucei, whereas the DNA-based technique revealed 19.0% and 2.4% prevalence for T. vivax and T. brucei infections respectively, with the overall prevalence being 21.4%. Samples from goats revealed 13.6% and 5.0% prevalence of T. vivax in male and female respectively, while 4.5% and 0% prevalence of T. brucei was observed in male and female respectively. Similarly, samples from sheep revealed 9.1% and 10.0% prevalence of T. vivax in males and females respectively. Generally, the findings showed that tryponosomosis is more associated with males than females, there was however no significant different (P &gt; 0.05). Furthermore, 23.8% and 19.0% prevalence was revealed by PCR in goats and sheep respectively. This shows that trypanosomiasis still exist and may worsen if not addressed properly in Kachia grazing reserve area of Kaduna State, and the use of microscopic evaluation alone might greatly underscore the prevalence rate.&#x0D; Keywords: Trypanosomosis, molecular diagnosis, prevalence, sheep and goats, Nigeria

Financial losses estimation of African animal trypanosomosis in Nigeria: field reality-based model.

Theoretical and modelling approaches were undertaken on Nigerian livestock industry to estimate financial losses due to African animal trypanosomosis. Surveys were conducted between March 2018 and February 2019 to include focus group interactions, in-depth household engagements concerning livestock practices in relation to AAT. Financial losses estimation on livestock were targeted to provide ways to regain cost and maximize household livelihoods. Mathematical equation was developed to project the effects of intervention strategies. Important variables such as mean AAT prevalence, incidence rate, birth rate, morbidity and mortality were estimated and inserted in the model. Mean total income per capita was US$ 1.31 / person / day among livestock producers in Nigeria. A total of US$ 518. 9 million were estimated from direct losses, while US$ 58.8 million as indirect losses. Annual estimated losses to AAT from cattle, sheep, goat and pigs in Nigeria is US$ 577.7 million. This is equivalent to 207.98 billion Nigerian naira and represents 6.93% of annual livestock GDP in the country. This could increase to 85% in the next 50 years if there are no proper control interventions. Control efforts could reduce the losses to US$ 16.7 million at the rate of 0.2% during the same period. AAT has severe socioeconomic impact on producer's livelihood and urgent improved control intervention strategies should be instituted to reduce the losses attributed to the disease.

Dispersal in heterogeneous environments drives population dynamics and control of tsetse flies.

Spatio-temporally heterogeneous environments may lead to unexpected population dynamics. Knowledge is needed on local properties favouring population resilience at large scale. For pathogen vectors, such as tsetse flies transmitting human and animal African trypanosomosis, this is crucial to target management strategies. We developed a mechanistic spatio-temporal model of the age-structured population dynamics of tsetse flies, parametrized with field and laboratory data. It accounts for density- and temperature-dependence. The studied environment is heterogeneous, fragmented and dispersal is suitability-driven. We confirmed that temperature and adult mortality have a strong impact on tsetse populations. When homogeneously increasing adult mortality, control was less effective and induced faster population recovery in the coldest and temperature-stable locations, creating refuges. To optimally select locations to control, we assessed the potential impact of treating them and their contribution to the whole population. This heterogeneous control induced a similar population decrease, with more dispersed individuals. Control efficacy was no longer related to temperature. Dispersal was responsible for refuges at the interface between controlled and uncontrolled zones, where resurgence after control was very high. The early identification of refuges, which could jeopardize control efforts, is crucial. We recommend baseline data collection to characterize the ecosystem before implementing any measures.

Optimizing the feeding frequency to maximize the production of sterile males in tsetse mass-rearing colonies.

Tsetse flies are cyclical vectors of trypanosomes, the causative agents of sleeping sickness or Human African Trypanosomosis and nagana or African Animal Trypanosomosis in Sub-Saharan Africa. The Insectarium de Bobo-Dioulasso (IBD) was created and equipped in the frame of Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) with the main goal to provide sterile males for the different eradication programs in West Africa which is already the case with the ongoing eradication program in Senegal. The aim of this study was to identify the best feeding regime in mass-rearing colonies of Glossina palpalis gambiensis to optimize the yield of sterile males. We investigated the mortality and fecundity for various feeding regimes and day alternation (3×: Monday-Wednesday-Friday, 4×: Monday-Wednesday-Friday-Saturday, 4×: Monday-Wednesday-Thursday-Friday and 6×: all days except Sunday) on adult tsetse flies in routine rearing over 60 days after emergence. The day alternation in the 4 blood meals per week (feeding regimes 2 and 3) had no effect on tsetse fly mortality and fecundity. The best feeding regime was the regime of 4 blood meals per week which resulted in higher significant fecundity (PPIF = 2.5; P = 0.003) combined with lower mortality of females (P = 0.0003) than the 3 blood meals per week (PPIF = 2.0) and in similar fecundity (PPIF = 2.6; P = 0.70) and mortality (P = 0.51) than the 6 blood meals per week. This feeding regime was extended to the whole colonies, resulting in an improved yield of sterile males for the ongoing eradication program in Senegal and would be more cost-effective for the implementation of the next-coming sterile insect technique (SIT) programs in West Africa.

Prevalence of trypanosomosis and associated haematological changes among hunting dogs in Abeokuta, Nigeria

African animal trypanosomosis (AAT) is one of the major constraints to the development of effective livestock production systems. Dogs are human companion and are believed to be sentinels for infection with the human species. This study was to detect subclinical and clinical infection of trypanosomes among hunting dogs in Abeokuta and its environs using molecular technique. A total of 87 dogs comprising of 49 males and 38 females were ramdomly screened for trypanosomes by polymerase chain reaction technique. Among 87 dogs screened, 17.2% were positive for Trypanosoma congolense and Trypanosoma brucei. Prevalence of trypanosomosis in males was 14.3% while the females accounted for 21.1%.Hematological examination revealed a significant increase (p &lt; 0.05) in mean white blood cells (20.9 ± 2.11) and monocyte counts (5.9 ± 0.62) of the infected dogs compared to uninfected dogs. Packed Cell Volume (36.0 ± 3.73) and haemoglobin concentration (13.9 ± 2.10) decreased insignificantly, while, red blood cells (7.1 ± 0.87), lymphocyte (60.9 ± 9.63), neutrophil (33.3 ± 9.16) and eosinophil (1.4 ± 0.42) counts increased insignificantly (p &gt; 0.05) in infected dogs compared to uninfected dogs. In conclusion, trypanosomosis is prevalent in hunting dogs, in Abeokuta.

Trypanosomosis prevalence in natural field-based infection: insights into systematic review and meta-analysis of studies from 1980 to 2018 on The Gambian ruminants with special emphasis on cattle.

Consistent quantification of trypanosomes, the parasite responsible for African animal trypanosomosis, is important for effective surveillance, control, and eradication strategies. Here, we used a rigorously predefined protocol to search and select eligible publications that utilized either microscopy, serology, or molecular methods to investigate prevalence of trypanosomosis based on the presence of any of three most common Trypanosoma spp. (T. congolense, T. vivax, and T. brucei) in the field-based naturally grazed Gambian cattle, sheep, and goats. To combine results of studies on cattle through meta-analysis, sensitivity and subgroup analyses were carried out with the random effects model, and prevalence estimates of each study with 95% confidence intervals (CI) were presented with a forest plot. All the eligible studies utilized the buffy coat technique (BCT) to detect trypanosomes in the blood samples, while the more sensitive serological and molecular detection methods are yet to be widely exploited. Heterogeneity among the studies on cattle was moderate (I2 = 55%), and the pooled trypanosomosis prevalence based on the BCT was 5.2% (95% CI: 4.0-6.4). Meanwhile, estimated prevalence varied according to the trypanosome detection methods, study locations, types of publication, year, and length of observations. We could not pool the trypanosomosis prevalence in sheep and goats through meta-analysis due to small number of studies. The prevalence estimates based on the BCT ranged from 3.2 to 8.1% in goats and 2.8 to 10.6% in sheep. Even though there seems to be a slight decrease in trypanosomosis prevalence in cattle in one of the Gambian districts, there was no consistent trend across the years. It is thought that the literature search and formatting procedures presented in this study contribute to doing systematic reviews on the investigated subject and can be adapted for similar cases.

Mathematical modelling and control of African animal trypanosomosis with interacting populations in West Africa-Could biting flies be important in main taining the disease endemicity?

African animal trypanosomosis (AAT) is transmitted cyclically by tsetse flies and mechanically by biting flies (tabanids and stomoxyines) in West Africa. AAT caused by Trypanosoma congolense, T. vivax and T. brucei brucei is a major threat to the cattle industry. A mathematical model involving three vertebrate hosts (cattle, small ruminants and wildlife) and three vector flies (Tsetse flies, tabanids and stomoxyines) was described to identify elimination strategies. The basic reproduction number (R0) was obtained with respect to the growth rate of infected wildlife (reservoir hosts) present around the susceptible population using a next generation matrix technique. With the aid of suitable Lyapunov functions, stability analyses of disease-free and endemic equilibria were established. Simulation of the predictive model was presented by solving the system of ordinary differential equations to explore the behaviour of the model. An operational area in southwest Nigeria was simulated using generated pertinent data. The R0 < 1 in the formulated model indicates the elimination of AAT. The comprehensive use of insecticide treated targets and insecticide treated cattle (ITT/ITC) affected the feeding tsetse and other biting flies resulting in R0 < 1. The insecticide type, application timing and method, expertise and environmental conditions could affect the model stability. In areas with abundant biting flies and no tsetse flies, T. vivax showed R0 > 1 when infected wildlife hosts were present. High tsetse populations revealed R0 <1 for T. vivax when ITT and ITC were administered, either individually or together. Elimination of the transmitting vectors of AAT could cost a total of US$ 1,056,990 in southwest Nigeria. Hence, AAT in West Africa can only be controlled by strategically applying insecticides targeting all transmitting vectors, appropriate use of trypanocides, and institutionalising an appropriate barrier between the domestic and sylvatic areas.

Molecular Detection of &lt;i&gt;Trypanosoma species&lt;/i&gt; in Cattle Slaughtered at Zango and Yantukwane Abattoirs in Zaria, Kaduna State, Nigeria

African animal trypanosomoses constitute the most important vector-borne cattle diseases in Sub-Saharan Africa. A total of170 blood samples were collected from cattle in Zango abattoir and Yantukwane abattoir in Zaria, Kaduna State. BloodSamples collected were examined for the presence of trypanosomes using the buffy coat technique and Giemsa thin bloodsmears which shows a single 1(0.58%; 1/170) infection using microscope. Positive and negative samples were subjected tofurther analysis using nested PCR reaction with nested primers for detection of trypanosomes, and 9 of the samples showedpositive bands after gel electrophoresis at 998bp (lane 1-9) indicating the presence of Trypanosoma theileri. Percentage, Chisquareand Odds ratio were used to analyse the data. A total of 9(5.29%; 9/170) animals were found infected with the parasiteout of which 4(4.65%; 4/85) were found in Zango abattoir, while 5 (5.95%) were found in Yantukwane abattoir. The resultswere not statistically (P&gt;0.05) location dependent. The infection in male (6.45%) cattle was higher than the female (4.63%)with no infection in young animals. No infection was observed in Sokoto Gudali breed, while White Fulani breed had 5.77%.From this study, it is clear that trypanosomosis is still a major obstacle to livestock production in Zaria and its Environs andthe incidence is majorly in adult cattle. In addition, nested PCR reaction showed more sensitivity than microscopy. Hence,there is need for proper diagnosis and treatment of animals to promote more beef and milk production for humanconsumption. Further study is necessary to determine the pathogenicity of T. theileri in other domestic animals.&#x0D; Keywords: Trypanosomosis, White Fulani, Sokoto Gudali, breed, infection.

Gamma Irradiation and Male Glossina austeni Mating Performance.

Simple SummaryAfrican animal trypanosomosis, also known as nagana, is a neglected disease in South Africa, transmitted by tsetse flies. It has been proposed to manage this disease through the eradication of Glossina austeni, one of the vectors of this disease in South Africa. The strategy would be an integration of various control tactics and the release of sterilised colonised males (sterile insect technique) to eliminate relic pockets. The irradiated colonised males must be able to compete with wild males. In preparation of the technique, the mating performance of colony-reared male flies was assessed. Factors that can influence male mating performance, such as radiation dose, and the development stage that is exposed to radiation were evaluated in the laboratory and under semi-field conditions. Radiation doses of 80 Gy and 100 Gy induced 97–99% sterility in colony females that mated with colony males treated as adults or pupae. Walk-in field cage assessments indicated that a dose of up to 100 Gy did not adversely affect the mating performance of males irradiated as adults or late stage pupae. This study indicated that the colonized G. austeni males irradiated as adults or late stage pupae will be suited for the sterile insect technique. An area-wide integrated pest management (AW-IPM) strategy with a sterile insect technique (SIT) component has been proposed for the management of African animal trypanosomosis (AAT) in South Africa. In preparation for the SIT, the mating performance of colony reared Glossina austeni males under influencing factors such as radiation dose and the development stage that is exposed to radiation, was assessed under laboratory and semi-field conditions. The radiation sensitivity of G. austeni colonized 37 years ago when treated as adults and late-stage pupae was determined. Radiation doses of 80 Gy and 100 Gy induced 97–99% sterility in colony females that mated with colony males treated as adults or pupae. Males irradiated either as adults or pupae with a radiation dose of 100 Gy showed similar insemination ability and survival as untreated males. Walk-in field cage assessments indicated that a dose of up to 100 Gy did not adversely affect the mating performance of males irradiated as adults or late stage pupae. Males irradiated as adults formed mating pairs faster than fertile males and males irradiated as pupae. The mating performance studies indicated that the colonized G. austeni males irradiated as adults or late stage pupae will still be suited for SIT.

Morphological, Molecular Identification and Distribution of Trypanosome-Transmitting Dipterans from Cattle Settlements in Southwest Nigeria.

Glossina spp. (Glossinidae), Tabanus spp. (Tabanidae), Ancala spp. (Tabanidae), Atylotus spp. (Tabanidae) and Stomoxys spp. (Muscidae) are important transmitting vectors of African animal trypanosomosis in sub-Saharan Africa. There is paucity of information on the distribution and identification of these flies in cattle settlements in southwest Nigeria. The distribution patterns, genetic variations and diversities of dipteran flies in southwest Nigeria were described and identified using morphological and molecular analysis of the 28S rDNA gene. Of the 13,895 flies examined morphologically between April 2016 and March 2017, tabanids were identified [Tabanus (0.34%), Ancala (0.03%), Atylotus (0.01%), Haematopota (0.014%) and Chrysops (0.11%)]. Two stomoxyine species were identified; Stomoxys niger niger Macquart (45.30%) and Stomoxys calcitrans Linnaeus (17.29%) and two Glossina spp. namely; Glossina p. gambiense Vanderplank, 1911 (0.46%) and Glossina tachinoides Westwood (0.51%) were identified. The identities were further confirmed in a BLAST search using their nucleotide sequences. The median-joining network of the 28S rDNA gene sequences indicated that fly species examined were genetically distinct. The apparent density of all the trapped flies was highest at a mean temperature of 26-28℃, humidity > 80% and rainfall of 150-220mm/month. The distribution of flies was observed to increase as vegetation increased in density and decreased in areas with relatively high human population density (> 100/km2). The population indices of the 28S rDNA gene of the flies suggest that analysis of nuclear DNA fragments may provide more information on the molecular ecology of these flies. Characterising fly species and assessing their impact are essential in distribution and monitoring AAT spread.

Studies on Comparative Hematological and Biochemical Changes in Yankasa Sheep Experimentally Infected with Trypanosoma vivax and Trypanosoma congolense Field Isolates of Nigerian Origin

Background: African Animal Trypanosomosis is one of the key hindrances to full livestock development in most parts of sub-Saharan Africa, despite years of efforts to eradicate the disease. It is an important parasitic disease of human and animals. Control of the disease relies majorly on chemotherapy of one of the three trypanocidal drugs. The severity of haematological indices depends on parasite species, host involved and nutrition. Hence, there is need to assess the pathogenicity and compare their effects on some of our local breeds of livestock.&#x0D; Methodology: Field isolates Trypanosoma vivax and Trypanosoma congolense of Nigerian origin were used. Thirty sheep were acquired and preconditioned for two weeks in arthropod- proofed pens before the commencement of the experiment. The sheep were divided into five groups (A- T. vivax infected-treated, B- T. vivax infected-untreated, C- No infection, no treatment, E- T. congolense infected-treated and F- T. congolense infected-untreated. Packed Cell Volume, serum protein, WBC, DLC were monitored weekly for 8 weeks.&#x0D; Results: There was gradual decreased in PCV of all the infected animals which was an indication of anaemia but more severe in T. vivax groups. Also decreased in plasma protein that was more pronounced and prolonged in T. vivax than the T. congolense groups, this was similar with WBC. Neutrophils had initial increased in all the groups before dropping and low value of monocyte at the early period of infections which later disappeared. There was no basophil seen in all the T.vivax groups but few were observed in T. congolense groups. &#x0D; Conclusion: Anaemia is a general feature of most parasitic infections especially in trypanosomosis. Trypanosoma vivax used in this study is more pathogenic than the T. congolense, hence may have more negative effects in sheep production in author’s environment.

In vitro and in vivo antitrypanosomal efficacy of combination therapy of Anogeissus leiocarpus, Khaya senegalensis and potash

Ethnopharmacological relevancePastoralists in Nigeria mix barks of Anogeissus leiocarpus (AL) Khaya senegalensis (KS) and potash (Pt) to treat animal African trypanosomosis. AimTo evaluate antitrypanosomal potential of A. leiocarpus, K. senegalensis and potash for insights into the traditional claim of antitrypanosomal combination therapy (ATCT). Materials and methodsFifty microliter each of six different concentrations of AL, KS, Pt, AL + KS, AL + KS + Pt and diminazene aceturate (DA, positive control) was incubated with 50 μL of parasite-laden blood containing 108Trypanosoma congolense cells in a 96-well microtitre plate. Negative control wells were devoid of the extracts and drug but supplemented with phosphate-buffered saline (PBS). Efficacy of treatment was observed at 1 h interval for complete immobilisation or reduced motility of the parasites. Each incubated mixture was inoculated into mouse at the point of complete immobilisation of parasite motility or at the end of 6-h observation period for concentrations that did not immobilise the parasites completely. For in vivo assessment, thirty-five parasitaemic rats were randomly allocated into seven groups of 5 rats each. Each rat in groups I–V was treated with 500 mg/kg of AL, KS, Pt, AL + KS and AL + KS + Pt, respectively, for 7 days. Rats in groups VI and VII were treated with diminazene aceturate 3.5 mg/kg once and PBS 2 mL/kg (7 days), which served as positive and negative controls, respectively. Daily monitoring of parasitaemia through the tail vein, packed cell volume and malondialdehyde were used to assess efficacy of the treatments. ResultsThe AL + KS + Pt group significantly (p < 0.05) and dose-dependently reduced parasite motility and completely immobilized the parasites at 10, 5 and 2.5 μg/μL with an IC50 of 9.1×10-4 µg/µL. All the mice with conditions that produced complete cessation of parasite motility did not develop parasitaemia within one month of observation. The AL + KS group significantly (p < 0.05) lowered the level of parasitaemia and MDA, and significantly (p < 0.05) maintained higher PCV than PBS group. ConclusionThe combination of A. leiocarpus and K. senegalensis showed better antitrypanosomal effects than single drug treatment and offers prospects for ATCT. Our findings support ethnopharmacological use of combined barks of A. leiocarpus and K. senegalensis by pastoralist in the treatment of animal African trypanosomosis in Nigeria.

From farmers to livestock keepers: a typology of cattle production systems in south-western Burkina Faso

Cattle production is an essential livelihood strategy in south-western Burkina Faso. Although having a distinct cultural role and known to be resistant against African animal trypanosomosis, the Lobi taurine cattle breed is endangered due to its low market value. As the first step in preservation efforts, our study aimed to develop a typology of production systems at the farm level. We used a structured questionnaire and focus group discussions for collecting data on household characteristics, socioeconomic activities, livestock, and access to services. The sample comprised 169 households in three communities. The analytical strategy included factor analysis of mixed data and hierarchical clustering. We identified four distinct types of cattle production systems: (1) sedentary Lobi farms, (2) sedentary crossbreed farms, (3) semi-transhumant Fulani zebu farms, and (4) transhumant Fulani zebu farms. Significant factors in developing this typology were the farmers’ ethnic group, crop diversity, cattle herd size, cattle herd composition, number of small ruminants, and livestock management strategies. Across all production systems, men were considered being primary decision-makers in cattle production, with women, herders, and children being responsible for specific tasks. All identified production systems are increasingly confronting disease pressure and scarcity of water and land. Future efforts in preservation and breeding will need to respond to these trends in the agroecosystem, integrate risk management measures, and resonate with the specific needs of the different household members involved in cattle rearing.

Structural and kinetic characterization of Trypanosoma congolense pyruvate kinase

Trypanosoma are blood-borne parasites and are the causative agents of neglected tropical diseases (NTDs) affecting both humans and animals. These parasites mainly rely on glycolysis for their energy production within the mammalian host, which is why trypanosomal glycolytic enzymes have been pursued as interesting targets for the development of trypanocidal drugs. The structure–function relationships of pyruvate kinases (PYKs) from trypanosomatids (Trypanosoma and Leishmania) have been well-studied within this context. In this paper, we describe the structural and enzymatic characterization of PYK from T. congolense (TcoPYK), the main causative agent of Animal African Trypanosomosis (AAT), by employing a combination of enzymatic assays, thermal unfolding studies and X-ray crystallography.