Prevalence Of Trypanosome Infections Research Articles

Bovine trypanosomosis, vector distribution and infection rate in three districts of Gamo Zone, southwestern Ethiopia

African animal trypanosomosis is one of the main obstacles to the development of livestock and agricultural output in Ethiopia. It usually results in a severe, frequently fatal sickness, and the infected animals were more weakened as the disease progress and become unfit for work. A cross sectional study design was conducted from December 2021 to April 2022 with the aim of estimating the prevalence of trypanosome infection both in Glossina spp. and cattle, and to assess apparent density of Glossina spp. A total of 298 cattle were selected and examined for trypanosome by using buffy coat technique. The overall prevalence of bovine trypanosomosis was 19.1%; and two species of trypanosomes, T. congolense and T. vivax, were identified in the study area. The prevalence of T. congolense and T. vivax were 15.8% and 2.3%, respectively. The prevalence of trypanosomosis was significantly higher in adult animals (OR = 2.7; p < 0.05) than in younger cattle and poor body condition (OR = 3.18; p < 0.05) than medium body condition animals. The mean PCV value of infected animals was 14.3% (13.3–15.4) significantly lower than the non-infected animals 18.5% (17.8–19.2). Glossina pallidipes is the only tsetse species encountered in all the study areas. In total, 2992 flies were caught of which 90.8% belong to G. pallidipes and 9.2% were other biting flies. The overall apparent density of G. pallidipes was 20.1 F/T/D and other biting flies were 2.0 F/T/D. A total of 307 live Glossina pallidipes were dissected. The overall prevalence of Glossina pallidipes infection rate was 9.1% (95% CI = 5.9–12.4). The prevalence of G. pallidipes infection was significantly higher in Kucha district (OR = 3.2, χ2 = 2.6, p < 0.05) than the other two districts, Daramalo and Arba Minch Zuria. Also it was significantly higher in flies trapped from riverine forest areas (OR = 5.5, χ2 = 2.86, p < 0.05). Therefore, to reduce the impact of trypanosomosis and Glossina, vector control and treating infected cattle with prophylactic or chemotherapeutic drugs and active community participation can play a key role.

A narrative review on trypanosomiasis and its effect on food production

Trypanosomiasis is an endemic parasitic disease affecting both humans and animal with a severe negative impact on food production in almost all parts of the world. This review seeks to summarize the history of trypanosomiasis and examine the prevalence of trypanosome infection in animals and its effects on food production. A narrative review was conducted on the history of trypanosomiasis. The literature search was conducted on different databases, and selected articles were screened, data extracted, and analyzed. It is believed that trypanosomiasis has been in existence for several decades dating as far as about 2500 BC during the era of the Egyptian kingdom. Africa was found to have the most common cases of animal trypanosomiasis, with 36 out of 40 articles reporting cases. Cattle among other mammals are the most studied animals and they are the most affected. Hence, milk and meat production are greatly affected by trypanosomiasis. The age of animals and the feed provided to animals also played a role in the prevalence and distribution of the pathogen. This review reveals a wide geographical distribution and diverse host range of trypanosome species. The study also highlights the severity of trypanosomiasis and its impact on food production.

Diversity of trypanosome species in small ruminants, dogs and pigs from three sleeping sickness foci of the south of Chad.

Despite considerable data generated on livestock trypanosomoses in tsetse-infested areas, little attention was paid for animal African trypanosomosis (AAT) in sleeping sickness foci. This study aimed to fill this gap by determining the diversity and prevalence of trypanosome species in animals from three Chadian human African trypanosomosis (HAT) foci. Blood samples were collected from 443 goats, 339 sheep, 228 dogs and 98 pigs of the Mandoul, Maro and Moissala HAT foci in the south of Chad. Capillary tube centrifugation (CTC) and specific primers were used to search trypanosomes. The prevalence of trypanosome infections was 6.3% for CTC and 22.7% for PCR. Trypanosomes of the sub-genus Trypanozoon had the highest prevalence (16.6%) while T. congolense savannah (1.9%) was least prevalent. Significant differences were recorded between the prevalence of trypanosome species (χ2 = 8.34; p = 0.04) and HAT foci (χ2 = 24.86; p ≤0.0001). Maro had the highest prevalence (32.7%) and Mandoul the lowest (17.4%). Significant differences were also recorded for T. congolense forest (χ2 = 45.106; p < 0.0001) and all T. congolense (χ2 = 34.992; p < 0.0001). Goats had the highest prevalence (26.9%) and sheep the lowest one (18.6%). Between animals, significant differences were recorded for trypanosome of the sub-genus Trypanozoon (χ2 = 9.443; p = 0.024), T. congolense forest (χ2 = 10.476; p = 0.015) and all T. congolense (χ2 = 12.152; p = 0.007). Of the 251 animals carrying trypanosome infections, 88.8% had single infections while 11.2% had more than one trypanosome species. The overall prevalence of single and mixed trypanosome infections were respectively 20.1% and 2.6% in animal taxa from of all foci. This study highlighted a diversity of trypanosomes in animal taxa of all HAT foci. It showed that AAT constitutes a threat for animal health and animal breeding in Chadian HAT foci. In these tsetse infested areas, reaching the elimination of AAT requires the designing and the implementation of control measures against trypanosome infections.

Molecular epidemiological survey of pathogenic trypanosomes in naturally infected cattle in northern Côte d'ivoire.

Bovine trypanosomiasis is a significant health concern for livestock intensification in Côte d'Ivoire. This study aimed to determine the prevalence and distribution of pathogenic trypanosomes and identify the most infected cattle breed in northern Côte d&apos;Ivoire. We examined 700 cattle and found that polymerase chain reaction (PCR) was more sensitive (12.3%) than microscopic observation (5.6%). Among the trypanosome species detected in naturally infected cattle, Trypanosoma vivax was 7.3%, Trypanosoma simiae tsavo was 6.7%, and Trypanosoma congolense was 0.4%. The overall prevalence of trypanosome infection in all cattle breeds was 12.3%, while the prevalence in individual breeds was 14.8%, 7.3%, 10.6%, and 12.3% for N'Dama, Baoule, Zebu, and Mere breed, respectively. The infected animals had low packed cell volume, influencing the prevalence. Our findings indicate that bovine trypanosomes are prevalent in Côte d'Ivoire, and their prevalence varies by region and breed. These pathogens include T. vivax, T. simiae tsavo, and T. congolense.

Seasonal Variation and Factors Affecting Trypanosoma theileri Infection in Wild Sika Deer (Ezo Sika Deer Cervus nippon yesoensis) in Eastern Hokkaido.

Trypanosoma (Megatrypanum) spp. are isolated from domestic and wild ruminants, including deer, worldwide. The prevalence of trypanosomes in mammals is influenced by a number of factors such as host age and vector abundance. However, the seasonal variation of and factors affecting trypanosome infection in the wild deer population remain elusive. In this study, we analyzed the seasonal variation in trypanosome prevalence and the factors that affect Trypanosoma theileri Laveran, 1902, infection in wild sika deer (Ezo sika deer) Cervus nippon yesoensis (Heude, 1884) in Eastern Hokkaido through a two-year survey. Seasonal variation in the prevalence of trypanosome infection in the deer population ranged from 0 to 41% as per hematocrit concentration and 17 to 89% as per PCR results. In general, the prevalence of T. theileri by PCR in 2020 was higher than that in 2019. Moreover, the prevalence was significantly higher in the aged population than among the younger population. These findings may explain why individual conditions and sampling season were associated with trypanosome prevalence. This is the first study to investigate the seasonal variation in and risk factors affecting trypanosome infection in wild deer.

Trypanosome infections in animals from tsetse infected areas of Cameroon and their sensitivity and resistance molecular profiles for diminazene aceturate and isometamidium chloride

Monitoring and assessment of control strategies for African trypanosomoses' elimination require not only updating data on trypanosome infections, but also to have an overview on the molecular profiles of trypanocides resistance in different epidemiological settings. This study was designed to determine, in animals from six tsetse-infested areas of Cameroon, the prevalence of trypanosome infections as well as the diminazene aceturate (DA) and isometamidium chloride (ISM) sensitivity/resistance molecular profiles of these trypanosomes. From 2016 to 2019, blood was collected in pigs, dogs, sheep, goats and cattle from six tsetse infested areas of Cameroon. DNA was extracted from blood and trypanosome species were identified by PCR. The sensitivity/resistance molecular profiles of trypanosomes to DA and ISM were investigated using PCR-RFLP. From 1343 blood samples collected, Trypanosoma vivax, Trypanosoma congolense forest and savannah, Trypanosoma theileri and trypanosomes of the sub-genus Trypanozoon were identified. The overall prevalence of trypanosome infections was 18.7%. These prevalence vary between trypanosome species, animal taxa, within and between sampling sites. Trypanosoma theileri was the predominant species with an infection rate of 12.1%. Trypanosomes showing resistant molecular profiles for ISM and DA were identified in animals from Tibati (2.7% for ISM and 65.6% for DA) and Kontcha (0.3% for ISM and 6.2% for DA). No trypanosome carrying resistant molecular profile for any of the two trypanocides was detected in animals from Fontem, Campo, Bipindi and Touboro. Mixed molecular profiles of sensitive/resistant trypanosomes were detected in animals from Tibati and Kontcha. Results of this study highlighted the presence of various trypanosome species as well as parasites carrying sensitive/resistant molecular profiles for DA and ISM in animals of tsetse infested areas of Cameroon. They indicate that the control strategies must be adapted according to epidemiological settings. The diversity of trypanosomes indicates that AAT remains a serious threat for animal breeding and animal health in these tsetse infested areas.

Prevalence of pathogenic trypanosome species in naturally infected cattle of three sleeping sickness foci of the south of Chad.

Although a diversity of trypanosome species have been detected in various animal taxa from human African trypanosomosis (HAT) foci, cattle trypanosomosis has not been addressed in HAT foci of west and central African countries including Chad. This study aimed to determine the prevalence of pathogenic trypanosome species in cattle from three HAT foci of the south of Chad. Blood samples were collected from 1466 randomly selected cattle from HAT foci of Mandoul, Maro, and Moïssala in the south of Chad. For each animal, the sex, age and body condition were recorded. Rapid diagnostic test (RDT) was used to search Trypanosoma brucei gambiense antibodies while the capillary tube centrifugation (CTC) test and PCR-based methods enabled to detect and identify trypanosome species. From the 1466 cattle, 45 (3.1%) were positive to RDT. The prevalence of trypanosome infections revealed by CTC and PCR-based method were respectively 2.7% and 11.1%. Trypanosomes of the subgenus Trypanozoon were dominant (6.5%) followed by T. congolense savannah (2.9%), T. congolense forest (2.5%) and T. vivax (0.8%). No animal was found with DNA of human infective trypanosome (T. b. gambiense). The overall prevalence of trypanosome infections was significantly higher in animal from the Maro HAT focus (13.8%) than those from Mandoul (11.1%) and Moïssala HAT foci (8.0%). This prevalence was also significantly higher in animal having poor body condition (77.5%) than those with medium (11.2%) and good (0.5%) body condition. The overall prevalence of single and mixed infections were respectively 9.4% and 1.6%. This study revealed natural infections of several pathogenic trypanosome species in cattle from different HAT foci of Chad. It showed similar transmission patterns of these trypanosome species and highlighted the need of developing control strategies for animal African trypanosomosis (AAT) with the overarching goal of improving animal health and the economy of smallholder farmers.

Molecular epidemiology of Animal African Trypanosomosis in southwest Burkina Faso.

Animal African Trypanosomosis (AAT) is a parasitic disease of livestock that has a major socio-economic impact in the affected areas. It is caused by several species of uniflagellate extracellular protists of the genus Trypanosoma mainly transmitted by tsetse flies: T. congolense, T. vivax and T. brucei brucei. In Burkina Faso, AAT hampers the proper economic development of the southwestern part of the country, which is yet the best watered area particularly conducive to agriculture and animal production. It was therefore important to investigate the extent of the infection in order to better control the disease. The objective of the present study was to assess the prevalence of trypanosome infections and collect data on the presence of tsetse flies. Buffy coat, Trypanosoma species-specific PCR, Indirect ELISA Trypanosoma sp and trypanolysis techniques were used on 1898 samples collected. An entomological survey was also carried out. The parasitological prevalence of AAT was 1.1%, and all observed parasites were T. vivax. In contrast, the molecular prevalence was 23%, of which T. vivax was predominant (89%) followed by T. congolense (12.3%) and T. brucei s.l. (7.3%) with a sizable proportion as mixed infections (9.1%). T. brucei gambiense, responsible of sleeping sickness in humans, was not detected. The serological prevalence reached 49.7%. Once again T. vivax predominated (77.2%), but followed by T. brucei (14.7%) and T. congolense (8.1%). Seven samples, from six cattle and one pig, were found positive by trypanolysis. The density per trap of Glossina tachinoides and G. palpalis gambiensis was 1.2 flies. Overall, our study showed a high prevalence of trypanosome infection in the area, pointing out an ongoing inadequacy of control measures.

Molecular survey of Trypanosoma congolense “Forest-Type” in Nigerian cattle

African animal trypanosomosis is an important livestock disease in Nigeria which is considered as a threat to the on-going effort on poverty alleviation in the continent. The disease is caused by several Trypanosoma species which are protozoan parasites transmitted by tsetse. Trypanosomosis is characterized by tissue injury including overwhelming activation of Classical Myeloid cells that results in destruction of the liver and uncontrolled parasite growth. Reduction in production and sometimes death are disease sequella. Hence, proper surveillance of the disease using a sensitive tool is very necessary for monitoring and control of trypanosomosis. Therefore this study concentrated on providing knowledge on the true infection rate of Trypanosoma congolense “forest type” and its effect on body weight and haematological parameters. Blood sample was collected from 180 cattle, DNA was extracted and PCR technique was adopted for prevalence study. Haematological analysis was carried out using Auto-haemo-analyser. Data generated were analysed using SAS statistical package. A prevalence rate of 91.67% was recorded. There were significant (p&lt;0.05) differences between Body-weight, Red Blood Cell count, Mean Corpuscular Volume and Monocyte number of infected and un-infected cattle. The haematology reveals that hosts were able to respond to anaemia compensatorily as perceived in the macro-cytic, normo-chromic status of the peripheral blood erythrocytic generation. The study concluded that the true prevalence of trypanosome infection is high and has both epidemiological and economic importance. This study `provides information that could facilitate future monitoring and control of the disease in the study area.

Parasitological and molecular identification of Trypanosoma species circulating in cattle and tsetse flies in Matutuine District, Maputo Province, Mozambique

Tsetse flies (Diptera: Glossinidae) are haematophagous insects of medical and veterinary importance due to their role in the transmission of trypanosomes. Tsetse-transmitted trypanosomosis is one of the major constraints to agriculture and livestock development in sub-Saharan Africa. Thus, the importance of the assessment of the distribution of both disease and vector in areas where cattle are kept, as is the case of Matutuíne district, where the last longitudinal study was conducted in 2000. From March 2009 to December 2012, 2427 bovine blood samples were collected in five administrative areas of Matutine district (Bela Vista, Zitundo, Catuane, Catembe and Machangulo). For each animal, the packed cell volume (PCV) was determined and blood examined for the presence of motile trypanosomes using microscopy. At the same time, tsetse flies were also captured. Additionally, DNA was extracted from both cattle blood and tsetse flies. The samples were further analysed using the 18S PCR–RFLP. Trypanosome infections in bovines were detected in all Matutuíne´s administrative areas. The overall prevalence of trypanosome infections was 15.62% by buffy coat and 47.34% by molecular testing. A total of 1379 tsetse flies (1379 Glossina brevipalpis and 150 G. austeni) were captured. From this, 408 were analysed by 18S PCR for the presence of trypanosomes. The results showed a percentage of infection of 12.74% and 3.19% for G. brevipalpis and G. austeni, respectively. With these results, it is concluded that tsetse-transmitted trypanosomosis is a major threat to cattle in Matutuine and control actions need to be implemented.

The prevalence of trypanosome infections in goats at Niassa National Reserve, Mozambique

African animal trypanosomosis (AAT), a debilitating tsetse-transmitted parasitic disease, is a major constraint to livestock ruminant production in Sub-Saharan Africa. In the southern Africa region, the main Trypanosoma species causing AAT include T. brucei, T. vivax and T. congolense. All three species have been described in acute, subacute, chronic or subclinical cases of AAT in goats. In the tsetse belt region, goat infections are estimated at 40 million per year. Despite this, the role of these small ruminants in the epidemiology of AAT is yet to be fully understood. To determine trypanosome prevalence and contribute to the understanding of the role of these small ruminants in the epidemiology of trypanosomosis, at Niassa National Reserve (NNR), a cross-sectional survey was conducted between July and September 2018 in five districts located inside the NNR (Sanga, Mavago, Majune, Marrupa and Mecula), Niassa Province, Mozambique. A total of 416 goat blood samples were collected and screened for trypanosomes using microscopy and Polymerase Chain Reaction (PCR). The overall prevalence was 0.96%, out of which, 0.72% corresponded to T. congolense and 0.24% to T. vivax. Mecula was the district with the highest prevalence (0.48%), followed by Sanga and Majune (both with 0.24%). Considering the aforementioned results, the role of goats in the epidemiology of the disease, within the NNR, may be considered negligible.

Occurrence, diversity and distribution of Trypanosoma infections in cattle around the Akagera National Park, Rwanda.

African Trypanosomiases threaten the life of both humans and animals. Trypanosomes are transmitted by tsetse and other biting flies. In Rwanda, the African Animal Trypanosomiasis (AAT) endemic area is mainly around the tsetse-infested Akagera National Park (NP). The study aimed to identify Trypanosoma species circulating in cattle, their genetic diversity and distribution around the Akagera NP. A cross-sectional study was carried out in four districts, where 1,037 cattle blood samples were collected. The presence of trypanosomes was determined by microscopy, immunological rapid test VerY Diag and PCR coupled with High-Resolution Melt (HRM) analysis. A parametric test (ANOVA) was used to compare the mean Packed cell Volume (PCV) and trypanosomes occurrence. The Cohen Kappa test was used to compare the level of agreement between the diagnostic methods. The overall prevalence of trypanosome infections was 5.6%, 7.1% and 18.7% by thin smear, Buffy coat technique and PCR/HRM respectively. Microscopy showed a low sensitivity while a low specificity was shown by the rapid test (VerY Diag). Trypanosoma (T.) congolense was found at a prevalence of 10.7%, T. vivax 5.2%, T. brucei brucei 2% and T. evansi 0.7% by PCR/HRM. This is the first report of T.evansi in cattle in Rwanda. The non-pathogenic T. theileri was also detected. Lower trypanosome infections were observed in Ankole x Friesian breeds than indigenous Ankole. No human-infective T. brucei rhodesiense was detected. There was no significant difference between the mean PCV of infected and non-infected animals (p>0.162). Our study sheds light on the species of animal infective trypanosomes around the Akagera NP, including both pathogenic and non-pathogenic trypanosomes. The PCV estimation is not always an indication of trypanosome infection and the mechanical transmission should not be overlooked. The study confirms that the area around the Akagera NP is affected by AAT, and should, therefore, be targeted by the control activities. AAT impact assessment on cattle production and information on the use of trypanocides are needed to help policymakers prioritise target areas and optimize intervention strategies. Ultimately, these studies will allow Rwanda to advance in the Progressive Control Pathway (PCP) to reduce or eliminate the burden of AAT.

Molecular identification and prevalence of trypanosomes in cattle distributed within the Jebba axis of the River Niger, Kwara state, Nigeria

BackgroundTrypanosomiasis is a fatal disease that threatens the economy of at least 37 countries in sub-Saharan Africa, particularly with regard to livestock farming. In this study, we investigated the prevalence of trypanosome infection in cattle, and molecularly identified the species of trypanosomes in infected cattle and the spatial distribution of trypanosome-infected herds along the Jebba axis of the River Niger.MethodsA randomized cross-sectional study was conducted along the Jebba axis of the River Niger by screening cattle from 36 herd clusters by nested PCR using ITS-1 generic primers. Data generated were analysed using the Chi-square test at a 95% confidence interval.ResultsMicroscopic examination revealed three infected cattle out of 398 examined, representing 0.8% prevalence. Twelve animals (3.0%) were positive by PCR. Our results showed a decline in the packed cell volume of infected animals (24.7%). The infection rates were categorized as single infection in 11/12 (91.7%) and mixed infection in 1/12 (8.3%). Animals were most frequently infected by Trypanosoma congolense (50.0%), with T. congolense Savannah being the most prevalent subspecies (71.4%). Aside from the infection rate by age (10.0%) and relative distance of animals from the River Niger (56.2%), statistical differences in every other parameter tested were based on mere probabilistic chance. Spatial data showed that the disease was prevalent among herds located less than 3 km from the River Niger.ConclusionsSix species of trypanosomes were identified in cattle herds along the Jebba axis of the River Niger, with T. congolense being the most prevalent. Age and relative distance of herds from the River Niger may be risk factors for trypanosome infection in cattle herds in this area.Graphical abstract

Prevalence and risk factors for trypanosome infection in cattle from communities surrounding the Murchison Falls National Park, Uganda

BackgroundBovine trypanosomosis transmitted by tsetse flies is a major constraint to cattle health and productivity in all sub-Saharan countries, including Uganda. The objectives of this study were to determine the prevalence of bovine trypanosomosis and identify its associated risk factors and the species of trypanosomes associated with the disease.MethodologyA cross-sectional study was conducted around Murchison Falls National Park, Uganda from January 2020 to April 2020. Trypanosomes were detected in blood samples by PCR analysis targeting the internal transcribed spacer 1 (ITS-PCR assays), and trypanosomes in positive blood samples were sequenced.ResultsOf 460 blood samples collected and tested, 136 (29.6%) were positive for trypanosome infections and 324 (70.4%) were negative. The overall trypanosome prevalence was 29.6% (95% confidence interval 25.4–33.8%), attributed to three trypanosome species. Of these three species, Trypanosoma vivax was the most prevalent (n = 130, 28.3%) while the others were detected as mixed infections: T. vivax + Trypanosomacongolense (n = 2, 0.4%) and T. vivax + Trypanosomaevansi (n = 1, 0.2%). There were significant differences in trypanosome prevalence according to sex (χ2 = 62, df = 1, P < 0.05), age (χ2 = 6.28, df = 2, P = 0.0043) and cattle breed (χ2 = 10.61, df = 1, P = 0.001).ConclusionsTrypanosomosis remains a major limitation to cattle production around Murchison Falls National Park and interventions are urgently needed. In our study, the prevalence of trypanosome infections was high, with T. vivax identified as the most prevalent species. Age, sex and breed of cattle were risk factors for trypanosome infection.Graphical

Bovine trypanosomosis and its vectors: prevalence and control operations in Kellem Wollega, Western Ethiopia

A cross-sectional study was conducted to estimate the prevalence of bovine trypanosomosis and to assess farmers’ perception of the disease and its control operations. From October to April 2012, a total of 586 cattle were sampled for the prevalence study. Buffy coat procedure and haematocrit value determination were performed. To capture the fly that was involved in the transmission dynamics, one hundred monopyramidal traps were deployed for 72 hours. A semi-structured questionnaire was conducted to study farmers’ perceptions of the diseases and their control operations. Trypanosomal infections were diagnosed in only 8.7 % (51) of animals. The overall prevalence of trypanosome infection in cattle was significantly varied between study districts (33.1% Dale Sadi and 66.9% Dale Wabera). Most infections were due to Trypanosoma congolense (81.8%) followed by T. vivax (15.6%) and mixed infections (2.6%). The association of hematological value changes and trypanosome infections was profound. The overall Packed Cell Volume (PCV) values of sampled cattle were 25.8%. A significant (P&lt; 0.05) variation in PCV values was recorded in infected (20.8%) and non-infected (26.5%) cattle. In the study period, a total of 2055 flies were captured and of which 92% belong to the genus Glossina followed by Stomoxys and Tabanids. Four types of tsetse species (G. pallidpes, G. m. morsitans, G. tachinoides, and G. f. fuscipes) were identified. The questionnaire survey revealed that trypanosomosis is the most important problem for agricultural activity and animal production in the study areas. Farmers are well aware of the problem, means of transmission, and the different control methods. Integrating tsetse control program with other trypanosomosis control options is recommended.

Paratransgenic manipulation of a tsetse microRNA alters the physiological homeostasis of the fly's midgut environment.

Tsetse flies are vectors of parasitic African trypanosomes, the etiological agents of human and animal African trypanosomoses. Current disease control methods include fly-repelling pesticides, fly trapping, and chemotherapeutic treatment of infected people and animals. Inhibiting tsetse's ability to transmit trypanosomes by strengthening the fly's natural barriers can serve as an alternative approach to reduce disease. The peritrophic matrix (PM) is a chitinous and proteinaceous barrier that lines the insect midgut and serves as a protective barrier that inhibits infection with pathogens. African trypanosomes must cross tsetse's PM in order to establish an infection in the fly, and PM structural integrity negatively correlates with trypanosome infection outcomes. Bloodstream form trypanosomes shed variant surface glycoproteins (VSG) into tsetse's gut lumen early during the infection establishment, and free VSG molecules are internalized by the fly's PM-producing cardia. This process results in a reduction in the expression of a tsetse microRNA (miR275) and a sequential molecular cascade that compromises PM integrity. miRNAs are small non-coding RNAs that are critical in regulating many physiological processes. In the present study, we investigated the role(s) of tsetse miR275 by developing a paratransgenic expression system that employs tsetse's facultative bacterial endosymbiont, Sodalis glossinidius, to express tandem antagomir-275 repeats (or miR275 sponges). This system induces a constitutive, 40% reduction in miR275 transcript abundance in the fly's midgut and results in obstructed blood digestion (gut weights increased by 52%), a significant increase (p-value < 0.0001) in fly survival following infection with an entomopathogenic bacteria, and a 78% increase in trypanosome infection prevalence. RNA sequencing of cardia and midgut tissues from paratransgenic tsetse confirmed that miR275 regulates processes related to the expression of PM-associated proteins and digestive enzymes as well as genes that encode abundant secretory proteins. Our study demonstrates that paratransgenesis can be employed to study microRNA regulated pathways in arthropods that house symbiotic bacteria.

Human-associated scarcity of hosts for tsetse flies (Diptera: Glossinidae) is related to an increase in prevalence of trypanosome infection in flies in north-eastern Zambia.

Occurrence of nutritional stress (due to depletion of fat reserves) in tsetse flies, associated with inadequate levels of access to blood meals, enhances susceptibility of the flies to trypanosome infection. Thus, in a tsetse-infested area, a spatial gradient of reducing tsetse habitat quality is potentially a gradient of increasing prospects for occurrence of stress in tsetse flies. This study investigated prevalence of trypanosome infection in Glossina morsitans morsitans and G. pallidipes along a transect line hypothesised to represent such a gradient, in relation to the edge of the tsetse belt and distribution of human settlements. This was undertaken in three sites located in Lundazi, Mpika and Rufunsa districts, respectively, in north-eastern Zambia. Human settlement was concentrated at the edge of the tsetse belt in the Mpika and Rufunsa sites and evenly distributed along transect line in the Lundazi site. Tsetse fly samples were collected using black-screen fly rounds and Epsilon traps. Detection of trypanosome infection was by dissection and microscopy in Lundazi and Mpika sites and loop-mediated isothermal amplification (LAMP) test in Rufunsa site. Multiple logistic regression models were applied to determine whether the following factors, 'change in distance from edge of tsetse belt', 'tsetse sampling method' and 'sex of tsetse fly', had effect on 'prevalence of trypanosome infection' in the tsetse flies. Only 'increase in distance from the edge of tsetse belt' for G. m. morsitans was significantly associated with 'prevalence of trypanosome infection' in the flies, in the Mpika and Rufunsa sites. Distance was associated with reduced likelihood of infection with 'one or more subgenera of trypanosomes' and with 'Nannomonas trypanosomes', in the case of 'all sites collectively', 'Lundazi and Mpika sites collectively', Mpika site alone, and Rufunsa site alone. Per site, increase in distance entailed reduced prospects for Trypanozoon infection but only in the Mpika and Rufunsa sites. We conclude that in the Mpika and Rufunsa sites, increase in distance from human settlements entailed reduced likelihood of trypanosome infection, likely due to reducing tsetse habitat degradation, increasing availability of hosts, and hence increasing levels of nutrition and fat reserves, thus enhancing tsetse immunity against trypanosome infection.

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

Distribution of tsetse flies and its Trypanosoma species infection in Old Oyo National Park, Nigeria

Tsetse fly infestation in national parks is a major health risk to both the wildlife and tourists coming to sub-Saharan Africa. However, information on distribution and diversity of tsetse flies and trypanosome infection rate in Protected Areas like Old Oyo National Park in south-west Nigeria is largely unknown. Thus, the study evaluates distribution and diversity of tsetse flies in Magurba Range of Old Oyo National Park. Twelve Nzi traps were set at 50 m equidistance to capture Glossina species for a period of six months between February and August, 2019, considering both the altitudinal and ecological significance. A total of 136 tsetse flies belonging to four species; G. palpalis, G. tachinoides, G. morsitans and G. fusca; were captured. More Glossina species were captured during dry season 77.9% (70.0-84.6) than the wet season 22.1% (15.4-30.0). There was significant difference (p = 0.0001; x2 = 84.9; OR = 12.5) between the proportion of Glossina species captured at the riverine areas (106; 77.9%) and the woodland/forest areas (30; 22.1%). Glossina captured at ground level and 30 cm above ground were 71 (52.2 %) and 65 (47.8%) respectively. The overall prevalence of trypanosome infection (2.94%) was observed for Glossina spp. The presence of infected Glossina spp. indicated an urgent need to establish a concise strategic vector control in National Parks, in order to reduce the risk of transmission to both wildlife and humans in the area. The park is frequently visited by tourists, rangers, researchers and students for educational purposes.&#x0D; Keywords: Glossina spp.; Trypanosoma spp.; vector distribution; Old Oyo National Park

THE PREVALENCE OF TRYPANOSOME INFECTIONS AMONG TRADE CATTLE IN SUBHUMID AND HUMID ZONES OF NIGERIA

The prevalence of trypanosome infections among trade cattle in the sub-humid and humid zones of Nigeria was investigated during a twelve-month period. The infections were prevalent throughout the year and a mean infection rate 11.04% was recorded in both zones, among 1,775 selected cattle. In the more northern area of sub-humid zone (Kaduna), mean prevalence was 12.16% in 989 cattle and monthly figures ranged from 2.10% to 19.62%. Trypanosome vivax and 7 congolense contributed almost equally to the infections being responsible for 36.6% and 35%, respectively of all positive cases. The importance of T. vivax, however, increase in Gboko (in the humid zone) where it was responsible for 50% of the parasitaemia encountered. Monthly prevalence in Gboko averaged 9.46% and ranged between 4.17% and 16.88%. Peak infections were common at the beginning of the dry season. The difference in PCV between infected and non-infected cattle was significant (P&lt;0.05) only in Kaduna where higher prevalence was also associated with increase differences in mean monthly PCV. T. brucei subspecies isolated from Gboko did not exhibit potentials for human infectivity: there were all T. brucei brucei, an animal pathogen.