A PCR-based survey of animal African trypanosomosis and selected piroplasm parasites of cattle and goats in Zambia

Molecular detection and internal transcribed spacer-1 sequence diversity of Trypanosoma evansi in goats from Cavite, Philippines

Goat production is an important source of livelihood and food. Goats may serve as reservoir of surra affecting livestock production. Here, forty-two free-roaming goats from Cavite, Philippines were screened using two primer sets, Trypanosoma brucei minisatellite chromosome for initial detection and the internal transcribed spacer 1 (ITS-1) to determine phylogeny. Initial PCR detection showed that 19/42 (45%) goats were positive, much higher than the rate previously reported in goats from Cebu (34%). The infectivity rate was higher in male (56%) than in female (42%) and the rate was higher in young ≤1 year old (100%) than in adult >1 year old (43%). Phylogenetic analysis of the ITS-1 sequences between T. evansi goat samples and other isolates indicate potential interspecies transmission.

Molecular genotyping reveals mixed bovine and human trypanosomiasis in cattle from West Africa

Background and Aim

Animal trypanosomiasis is a major contributor to agricultural and economic losses, especially in sub-Saharan Africa. We have shown that some animal species expressed genes that are significant players in immune response to bovine trypanosomosis, impeding signs and symptoms of the disease. We hypothesize that such animals are contributors to disease transmission dynamics and severe outcomes. Therefore, this study aims to ascertain trypanosome species diversity in cattle and their potential role as reservoirs for the transmission of human disease.

Materials and Methods

We performed a molecular genotyping of trypanosome internal transcribed spacer 1 (ITS-1) and 18S ribosomal RNA genes on genomic DNA extracts from randomly sampled N'Dama cattle from slaughterhouses in Nigeria. We identified trypanosome species circulating among the animals through polymerase chain reaction and genomic sequencing. We performed multiple sequence alignments as well as conducted a phylogenetic relationship between identified species.

Results

In all, 9 of 127 (7.1%) samples were positively amplified (band sizes ranging from 250 bp to 710 bp), including an isolate with two distinct bands (700 and 710 bp), indicating two trypanosome types. Sequence similarity and homology analysis identified four species, namely: Trypanosoma vivax, Trypanosoma congolense forest type, T. congolense savannah type, and Trypanosoma brucei. Interestingly, one of the bands, additionally verified by nucleotide sequencing, was identified as a human trypanosome (Trypanosoma brucei gambiense), confirming our hypothesis that cattle are potential reservoir hosts for human trypanosomes.

Conclusion

Overall, we observed different trypanosome species in our study area, with animals on the same farm infected with multiple species, which could complicate treatment and disease control strategies. Finding human trypanosome species strengthens the argument that disease transmission dynamics are modulated by other vertebrates, further complicating control programs.

Epidemiology of Ticks and Tick-Borne Pathogens in Domestic Ruminants across Southern African Development Community (SADC) Region from 1980 until 2021: A Systematic Review and Meta-Analysis

Ticks are hematophagous ectoparasites that are capable of infesting a wide range of mammals, including domestic animals, ruminants, wildlife, and humans across the world, and they transmit disease-causing pathogens. Numerous individual epidemiological studies have been conducted on the distribution and prevalence of ticks and tick-borne diseases (TBDs) in the Southern African Developing Community (SADC) region, but no effort has been undertaken to synchronize findings, which would be helpful in the implementation of consolidated tick control measures. With the aim of generating consolidated pooled prevalence estimates of ticks and TBDs in the SADC region, we performed a systematic review and meta-analysis of published articles using the PRISMA 2020 guidelines. A deep search was performed on five electronic databases, namely, PubMed, ScienceDirect, Google Scholar, AJOL, and Springer Link. Of the 347 articles identified, only 61 of the articles were eligible for inclusion. In total, 18,355 tick specimens were collected, belonging to the genera Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus (including Boophilus) across several countries, including South Africa (n = 8), Tanzania (n = 3), Zambia (n = 2), Zimbabwe (n = 2), Madagascar (n = 2), Angola (n = 2), Mozambique (n = 1), and Comoros (n = 1). The overall pooled prevalence estimate (PPE) of TBPs in livestock was 52.2%, with the highest PPE in cattle [51.2%], followed by sheep [45.4%], and goats [29.9%]. For bacteria-like and rickettsial TBPs, Anaplasma marginale had the highest PPE of 45.9%, followed by A. centrale [14.7%], A. phagocytophilum [2.52%], and A. bovis [0.88%], whilst Ehrlichia ruminantium had a PPE of 4.2%. For piroplasmids, Babesia bigemina and B. bovis had PPEs of 20.8% and 20.3%, respectively. Theileria velifera had the highest PPE of 43.0%, followed by T. mutans [29.1%], T. parva [25.0%], and other Theileria spp. [14.06%]. Findings from this study suggest the need for a consolidated scientific approach in the investigation of ticks, TBPs, and TBDs in the whole SADC region, as most of the TBDs are transboundary and require a regional control strategy.

Seroepidemiology of selected transboundary animal diseases in goats in Zambia

Transboundary pathogens of goats present significant constraints to the livelihoods of millions of farmers in countries such as Zambia. Consequently, this study aimed to investigate the seroprevalence of Mycoplasma capricolum subsp. capripneumoniae (Mccp), foot and mouth disease virus (FMDV), Brucella spp., Crimean Congo haemorrhagic fever virus (CCHFV), and Rift Valley fever virus (RVFV) in Zambian goats. Another aim was to identify associations between seroprevalence and different predictor variables, such as trade and border proximity. From September to October 2019, 962 serum samples were collected from goats in seven Zambian districts, four of which have an international border while the remaining three do not. A questionnaire survey was conducted with each household, focusing on trade routines, management strategies and herd disease history. Animal-level seroprevalence adjusted for herd-level clustering was 8.2 % (95 % confidence interval [CI] 7.5-9.0) for Mccp, 12.9% (95% CI 12.0-13.7) for FMDV, 13.0 % (95% CI 12.1-13.9) for Brucella spp., 3.3 % (95% CI 2.8-3.7) for CCHFV, and 0.4 % (95 % CI 0.3-0.7) for RVFV. The association between herd-level seroprevalence and border proximity and trade appeared negligible, with the exception of selling goats at least twice a year which was identified as a potential risk factor for Brucella spp. (OR 4.1, 95 % CI 1.1-16.0, p = 0.040). In addition, a positive association between herd-level seroprevalence of FMDV and a herd size of 21 goats or more (OR 3.3, 95 % CI 1.0-11.1, p = 0.049) was detected. Also, positive associations between animal-level seroprevalence of Brucella spp. and increasing age (OR 7.7, 95 % CI 1.5-40.7, p = 0.016), and CCHFV and keeping pigs in the household (OR 2.7, 95 % CI 1.0-7.1, p = 0.044), were found. For FMDV (OR 3.8, 95 % CI 1.4-10.9, p = 0.011) and Brucella spp. (OR 4.5, 95 % CI 1.2-17.3, p = 0.031) on the other hand, animal-level seroprevalence was significantly higher in households without pigs. To the best of the authors' knowledge, this is the first study to describe the presence of antibodies for CCPP and CCHF in the Zambian goat population. While the association between seroprevalence and trade and border proximity generally appeared negligible, it is recommended that their influence is further evaluated in future studies, preferably through in-depth longitudinal studies incorporating impacts of different biosecurity measures and trade variations, linked to for example seasonality and trade peaks.

Benzophenone Glucosides and B-Type Proanthocyanidin Dimers from Zambian Cassia abbreviata and Their Trypanocidal Activities

Two benzophenone glucosides (1 and 2), five flavan-3-ol dimers (5-9), and 17 known compounds (3, 4, and 10-24) were identified from the bark extract of Cassia abbreviata. The chemical structures display two points of interest. First, as an unusual characteristic feature of the ¹H NMR spectra of 1 and 2, the signals for the protons on glucosidic carbons C-2 are shielded as compared to those generally observed for glucosyl moieties. The geometrically optimized 3D structures derived from conformational analysis and density functional theory (DFT) calculations revealed that this shielding effect originates from intramolecular hydrogen bonds in 1 and 2. Additionally, 3-15 were identified as dimeric B-type proanthocyanidins, which have 2R,3S-absolute-configured C-rings and C-4-C-8″ linkages, as evidenced by X-ray crystallography and by NMR and ECD spectroscopy. These results suggest the structure-determining procedures for some reported dimers need to be reconsidered. The trypanocidal activities of the isolated compounds against Trypanosoma brucei brucei, T. b. gambiense, T. b. rhodesiense, T. congolense, and T. evansi were evaluated, and the active compounds were identified.

Development of Cathepsin L-like Real-Time PCR Assays for the Detection of African Animal Trypanosomosis (AAT) in South Africa

African animal trypanosomosis (AAT), is an infectious parasitic disease of wildlife and livestock caused by multiple species and strains of Trypanosoma. In South Africa, it is restricted to northern KwaZulu-Natal (NKZN) and caused by Trypanosoma congolense and Trypanosoma vivax. A cross-sectional study was done to determine AAT prevalence in 384 goat samples and identify trypanosome species circulating in 60 cattle at dip tanks that are on the interface with the Hluhluwe-uMfolozi game reserve in NKZN. Both cattle and goat samples were analyzed using the buffy coat technique (BCT) and a polymerase chain reaction (PCR) assay targeting the internal transcribed spacer 1 (ITS) region. Cattle samples were further analyzed using an ITS quantitative real-time PCR (qPCR) assays designed for the detection of T. congolense, T. vivax, and T. brucei. None of the goat samples tested positive for Trypanosoma infections. The ITS qPCR assay detected Trypanosoma DNA in 30% of the cattle samples, while only 8.3% were positive with the ITS PCR and 11.7% were positive using BCT. Quantitative real-time PCR assays were designed to amplify a 98 bp, 137 bp, and 116 bp fragment of the cathepsin L-like (CATL) gene from T. brucei, T. theileri, and T. congolense, respectively. Each assay was shown to be efficient (>94%) and specific (10⁹ to 10²/10¹ copies/reaction) in the detection of Trypanosoma species. The CATL qPCR assays detected T. congolense and T. theileri infections in 33.3% of the cattle samples. The CATL qPCR assays also detected T. congolense infections in goats (23.1%) that were neither detected by BCT nor the ITS PCR. The CATL qPCR assays provide an additional, sensitive, and specific tool for Trypanosoma diagnostics. The presence of trypanosomes in goats suggests they might be potential reservoirs of infections to other livestock.

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

Background

Bovine 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.

Methodology

A 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.

Results

Of 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).

Conclusions

Trypanosomosis 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 Abstract

Epidemiology of Trypanosomiasis in Wildlife-Implications for Humans at the Wildlife Interface in Africa

While both human and animal trypanosomiasis continue to present as major human and animal public health constraints globally, detailed analyses of trypanosome wildlife reservoir hosts remain sparse. African animal trypanosomiasis (AAT) affects both livestock and wildlife carrying a significant risk of spillover and cross-transmission of species and strains between populations. Increased human activity together with pressure on land resources is increasing wildlife–livestock–human infections. Increasing proximity between human settlements and grazing lands to wildlife reserves and game parks only serves to exacerbate zoonotic risk. Communities living and maintaining livestock on the fringes of wildlife-rich ecosystems require to have in place methods of vector control for prevention of AAT transmission and for the treatment of their livestock. Major Trypanosoma spp. include Trypanosoma brucei rhodesiense, Trypanosoma brucei gambiense, and Trypanosoma cruzi, pathogenic for humans, and Trypanosoma vivax, Trypanosoma congolense, Trypanosoma evansi, Trypanosoma brucei brucei, Trypanosoma dionisii, Trypanosoma thomasbancrofti, Trypanosma elephantis, Trypanosoma vegrandis, Trypanosoma copemani, Trypanosoma irwini, Trypanosoma copemani, Trypanosoma gilletti, Trypanosoma theileri, Trypanosoma godfreyi, Trypansoma simiae, and Trypanosoma (Megatrypanum) pestanai. Wildlife hosts for the trypansomatidae include subfamilies of Bovinae, Suidae, Pantherinae, Equidae, Alcephinae, Cercopithecinae, Crocodilinae, Pteropodidae, Peramelidae, Sigmodontidae, and Meliphagidae. Wildlife species are generally considered tolerant to trypanosome infection following centuries of coexistence of vectors and wildlife hosts. Tolerance is influenced by age, sex, species, and physiological condition and parasite challenge. Cyclic transmission through Glossina species occurs for T. congolense, T. simiae, T. vivax, T. brucei, and T. b. rhodesiense, T. b. gambiense, and within Reduviid bugs for T. cruzi. T. evansi is mechanically transmitted, and T. vixax is also commonly transmitted by biting flies including tsetse. Wildlife animal species serve as long-term reservoirs of infection, but the delicate acquired balance between trypanotolerance and trypanosome challenge can be disrupted by an increase in challenge and/or the introduction of new more virulent species into the ecosystem. There is a need to protect wildlife, animal, and human populations from the infectious consequences of encroachment to preserve and protect these populations. In this review, we explore the ecology and epidemiology of Trypanosoma spp. in wildlife.

Prevalence of Trypanosoma congolense and Trypanosoma vivax in Lira District, Uganda

Trypanosomes are the causative agents of animal African trypanosomiasis (AAT) and human African trypanosomiasis (HAT), the former affecting domestic animals prevalent in Sub-Saharan Africa. The main species causing AAT in cattle are T. congolense, T. vivax, and T. b. brucei. Northern Uganda has been politically unstable with no form of vector control in place. The return of displaced inhabitants led to the restocking of cattle from AAT endemic areas. It was thus important to estimate the burden of trypanosomiasis in the region. This study was designed to compare the prevalence of animal African trypanosomes in cattle in Lira District using microscopy and polymerase chain reaction amplification (PCR) methods. In this cross-sectional study, a total of 254 cattle from the three villages of Acanakwo A, Barropok, and Acungkena in Lira District, Uganda, were selected by simple random sampling technique and screened for trypanosomiasis using microscopy and PCR methods. The prevalence of trypanosomiasis according to microscopic results was 5/254 (2.0%) as compared to 11/254 (4.3%) trypanosomiasis prevalence according to PCR analysis. The prevalence of trypanosomiasis infection in the animal studied is 11/254 (4.3%). Trypanosoma congolense was the most dominant trypanosome species with a proportion of 9/11 (81.8%), followed by T. vivax 1/11 (9.1%) and mixed infection of T. congolense/T. vivax1/11 (9.1%). Barropok village had the highest prevalence of trypanosomiasis with 6/11 (54.5%). There is a statistically significant relationship (OR = 6.041; 95% CI: 1.634-22.331; p < 0.05) between abnormal PCV and trypanosome infection. Polymerase reaction amplification was the most reliable diagnostic method due to its high sensitivity and specificity as compared to the conventional microscopic method. Polymerase reaction amplification appears to have adequate accuracy to substitute the use of a microscope where facilities allow. This study, therefore, underscores the urgent need for local surveillance schemes more especially at the grassroots in Uganda to provide data for reference guideline development needed for the control of trypanosomiasis in Uganda.

Challenges in the Diagnostic Performance of Parasitological and Molecular Tests in the Surveillance of African Trypanosomiasis in Eastern Zambia

African animal trypanosomiasis (AAT) control programs rely on active case detection through the screening of animals reared in disease endemic areas. This study compared the application of the polymerase chain reaction (PCR) and microscopy in the detection of trypanosomes in cattle blood in Mambwe, a rural district in eastern Zambia. Blood samples were collected from 227 cattle and tested for infection with trypanosomes using microscopy and Ribosomal RNA Internal Transcribed Spacers (ITS)-PCR. Microscopy on the buffy coat detected 17 cases, whilst thin and thick smears detected 26 cases and 28 cases, respectively. In total, microscopy detected 40 cases. ITS-PCR-filter paper (FP) on blood spots stored on FP detected 47 cases, and ITS-PCR-FTA on blood spots stored on Whatman FTA Classic cards detected 83 cases. Using microscopy as the gold standard, ITS-PCR-FTA had a better specificity (SP) and sensitivity (SE) (SP = 72.2%; SE = 77.5%; kappa = 0.35) than ITS-PCR-FP (SP = 88%; SE = 60%; kappa = 0.45). The prevalence of Trypanosoma brucei s.l. was higher on ITS-PCR-FTA (19/227) than on ITS-PCR-FP (0/227). Our results illustrate the complexities around trypanosomiasis surveillance in rural Africa and provide evidence of the impact that field conditions and staff training can have on diagnostic results, which in turn impact the success of tsetse and trypanosomiasis control programs in the region.

Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys

Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.

Global distribution, host range and prevalence of Trypanosoma vivax: a systematic review and meta-analysis

BACKGROUND

Trypanosomosis caused by Trypanosoma vivax is one of the diseases threatening the health and productivity of livestock in Africa and Latin America. Trypanosoma vivax is mainly transmitted by tsetse flies; however, the parasite has also acquired the ability to be transmitted mechanically by hematophagous dipterans. Understanding its distribution, host range and prevalence is a key step in local and global efforts to control the disease.

METHODS

The study was conducted according to the methodological recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. A systematic literature search was conducted on three search engines, namely PubMed, Scopus and CAB Direct, to identify all publications reporting natural infection of T. vivax across the world. All the three search engines were screened using the search term Trypanosoma vivax without time and language restrictions. Publications on T. vivax that met our inclusion criteria were considered for systematic review and meta-analysis.

RESULT

The study provides a global database of T. vivax, consisting of 899 records from 245 peer-reviewed articles in 41 countries. A total of 232, 6277 tests were performed on 97 different mammalian hosts, including a wide range of wild animals. Natural infections of T. vivax were recorded in 39 different African and Latin American countries and 47 mammalian host species. All the 245 articles were included into the qualitative analysis, while information from 186 cross-sectional studies was used in the quantitative analysis mainly to estimate the pooled prevalence. Pooled prevalence estimates of T. vivax in domestic buffalo, cattle, dog, dromedary camel, equine, pig, small ruminant and wild animals were 30.6%, 6.4%, 2.6%, 8.4%, 3.7%, 5.5%, 3.8% and 12.9%, respectively. Stratified according to the diagnostic method, the highest pooled prevalences were found with serological techniques in domesticated buffalo (57.6%) followed by equine (50.0%) and wild animals (49.3%).

CONCLUSION

The study provides a comprehensive dataset on the geographical distribution and host range of T. vivax and demonstrates the potential of this parasite to invade other countries out of Africa and Latin America.

First molecular detection and identification of Trypanosoma evansi in goats from Cebu, Philippines using a PCR-based assay

The increasing number and severity of surra outbreaks in the Philippines led the government to consider it as the second most important disease of livestock in the country. It is one of the most economically important animal parasitic diseases and has been reported in several animal species, including water buffaloes, cattle, and horses in different regions of the Philippines. However, it has not yet been reported in Cebu, the usual gateway of livestock trade in the area that raises 6% of the 3.75 million goats in the country. In the current study, a PCR-based assay was conducted for the molecular detection and characterization of Trypanosoma evansi in goats in Cebu. A total of 251 goats were randomly sampled from four farms. DNA was extracted and ITS1-PCR was applied to detect different trypanosomes in goats. Eighty-five out of the 251 (33.9%) samples tested positive for T. evansi, two of which were also positive for T. theileri-like trypanosome. The detection rate of T. evansi was slightly higher in male goats (38.3%) than in females (32.5%), and in younger goats (34.5%) than in adults (33.5%). The findings, however, did not differ significantly to suggest any association between sex and age with T. evansi infection in goats. The detection of T. evansi and T. theileri-like trypanosome in goats was confirmed by sequence analysis of ITS1 region. To our knowledge, this is the first report on the molecular detection and identification of caprine T. evansi infection in Cebu, Philippines.

Prevalence of different trypanosomes in livestock in Blue Nile and West Kordofan States, Sudan

African animal trypanosomosis, transmitted cyclically by tsetse flies or mechanically by other biting flies, causes serious health problems in livestock. Although tsetse infestations have been observed in Blue Nile State in Sudan, tsetse was eradicated in West Kordofan in 1962, and no further studies have been carried out. Accordingly, in this study, we investigated the prevalence of trypanosomosis in cattle, sheep, and goats in Blue Nile and West Kordofan States, Sudan. This cross-sectional study was conducted using 70 cattle, 62 sheep, and 116 goats, and the microhematocrit centrifugation technique was used as a parasitological test. KIN-multispecies polymerase chain reaction (PCR) was used to detect Trypanozoon sp., Trypanosoma congolense, and T. vivax; RoTat 1.2 variable surface glycoprotein-specific PCR was used to detect T. evansi; and TviCatL PCR was used to specifically detect T. vivax. The seroprevalence of trypanosomosis was assessed using card agglutination tests CATT/ T. evansi. The parasitological prevalence rates were 4% (3/70) in cattle, 2% (1/62) in sheep, and 4% (5/116) in goats. The molecular prevalence rates of T. vivax, the most prevalent parasite, were 99% (69/70) in cattle, 98% (61/62) in sheep, and 84% (98/116) in goats. Trypanozoon (T. evansi or T. brucie) rates were 30% (21/70) in cattle, 32% (20/62) in sheep, and 12% (14/116) in goats. Among Trypanozoon-positive isolates, T. evansi was confirmed in 24% (5/21) of cattle, 70% (14/20) of sheep, and 86% (12/14) of goats. Finally, T. congolense was recorded only in cattle in Blue Nile State, with a prevalence of 14% (10/70). The seroprevalence rates of CATT/T. evansi were 46% (32/70) in cattle, 45% (28/62) in sheep, and 14% (16/116) in goats. Thus, we confirmed molecularly, for the first time, the presence of Trypanozoon, particularly T. evansi and T. vivax, in sheep and goats in Sudan. Our results show that sheep and goats could be an important reservoir for trypanosomes, potentially leading to the spread of the disease to the northern parts of the country following the movement of these animals. These findings provide important insights into the epidemiology of the disease and could affect the establishment of control strategies against trypanosomosis in Sudan.

A systematic review and meta-analysis of small ruminant and porcine trypanosomiasis prevalence in sub-Saharan Africa (1986 to 2018)

The appraisal of the disease burden of African animal trypanosomiasis (AAT) in some livestock at country level could invite a re-evaluation of trypanosomiasis-control strategy. This study thus estimates small ruminant and porcine trypanosomiasis prevalence in sub-Saharan African countries. It also describes Trypanosoma species prevalence in small ruminants and pigs and attempts identification of factors explaining between-study variations in prevalence. Articles reporting animal trypanosomiasis prevalence in sheep, goats, and pigs in countries within sub-Saharan Africa were retrieved from different databases (PubMed, Science Direct, Google Scholar, and African Journal Online) and reference lists of relevant literatures. A total of 85 articles from 13 countries published between 1986 and 2018 were included in the analysis. Overall random-effects meta-analytic mean prevalence estimates were: 7.67% (95% CI: 5.22-10.49), 5.84% (95% CI: 3.81-8.23), and 19.46% (95% CI: 14.61-24.80) respectively, for sheep, goats, and pigs with substantial heterogeneity (I² = >95.00%. p < 0.0001) noted between studies. Ovine, caprine, and porcine prevalence were highest in Tanzania (91.67%. 95% CI: 76.50-99.84), Equatorial Guinea (27%. 95% CI: 0-81.09), and Cameroon (47%. 95% CI: 29.67-66.06), respectively. Trypanosoma brucei s. l., T. vivax, and T. congolense were the most prevalent in the livestock. Trypanosoma brucei subspecies (T. b. gambiense and T. b. rhodesiense) occurred in all three livestock being mostly prevalent in pigs. Country of study was a significant predictor of trypanosomiasis prevalence in each livestock in addition to time and sample size for caprine hosts, diagnostic technique for both caprine and ovine hosts, and sample size for porcine hosts. The pattern of animal trypanosomiasis prevalence in the studied livestock reflects their susceptibility to trypanosomal infections and tsetse fly host feeding preferences. In conclusion, sheep, goats, and especially pigs are reservoirs of human infective trypanosomes in sub-Saharan Africa; consequently, their inclusion in sleeping sickness control programmes could enhance the goal of the disease elimination.

A meta-analysis of the prevalence of bovine trypanosomiasis in some African countries from 2000 to 2018

Bovine trypanosomiasis is a disease of cattle. In sub-Saharan Africa, the disease mean prevalence estimates are unknown in most endemic countries. We therefore performed a meta-analysis with the aim of estimating national mean prevalence of bovine trypanosomiasis in endemic countries across sub-Saharan Africa. Relevant articles reporting bovine trypanosomiasis prevalence were retrieved through systematic literature search and scanning of articles reference-lists. Eligibility criteria included that articles reported sample size, prevalence, and diagnostic technique adopted. Overall, data from 180 eligible articles from 19 countries satisfied the inclusion criteria. Meta-analysis of prevalence data based on the random-effects model resulted in an overall mean prevalence of 15.10% (95% CI: 13.22-17.08). National prevalence estimates were generally high except those of Benin and Senegal where estimates ranked below 10.00%. Significant heterogeneity (I² = 98.75%. p = <0.0001) was noted between studies, and univariate meta-regression analysis identified choice of diagnostic method being major contributor to observed heterogeneity (R² = 36.37%); while country of study (R² = 9.57%) and sample size (R² = 3.47%) had marginal effect on heterogeneity. In spite of past and ongoing control activities, bovine trypanosomiasis remains highly prevalent in most endemic sub-Saharan African countries. Nevertheless, dearth of epidemiological data in some countries and the use of less sensitive diagnostic tools limit reliable estimation of the disease prevalence. Therefore, there is the need to intensify efforts in aspects of surveillance and increased application of molecular diagnostic tool(s) across endemic locations as this would raise the chances of achieving a near-accurate estimate of the disease prevalence which is the first step to attempting eradication.