RESUMEN
Good dog-keeping practices and access to veterinary care are essential for the well-being of dogs. As the main causes of morbidity and mortality in the rural canine population in Zambia are poorly understood, we followed a cohort of 162 indigenous dogs for six months in wildlife-populated and tsetse-infested villages of Mambwe district, eastern Zambia to gain deeper insights. Dogs lacked basic home and veterinary care, they were often starved and burdened with ticks, and some passed live adult worms in their stool. The frequent exposure of dogs to tsetse bites and consumption of fresh raw game meat and bones puts them at greater risk of acquiring African trypanosomiasis. Nearly 20 % of dogs were lost to follow-up, with the main causes being poor health (58.1 %), predation by wild carnivores (29 %), and owner culling or euthanasia (12.9 %). We observed that indigenous dogs' general well-being and survival were largely influenced by their environment, infectious diseases, injuries sustained during interaction with conspecifics and wildlife, and community attitudes and practices associated with dog ownership.
Asunto(s)
Animales Salvajes , Enfermedades de los Perros , Animales , Perros , Enfermedades de los Perros/epidemiología , Zambia/epidemiología , Eutanasia Animal , DemografíaRESUMEN
Rickettsiales of the genus Anaplasma are globally distributed tick-borne pathogens of animals and humans with complex epidemiological cycles. Anaplasmosis is an important livestock disease in Zambia but its epidemiological information is inadequate. This study aimed to detect and characterize the species of Anaplasma present in domestic and wild ruminants in Zambia with a focus on the infection risk posed by the translocation of sable antelope (Hippotragus niger) from North-Western Province to Lusaka Province. Archived DNA samples (n = 100) extracted from whole blood (sable n = 47, cattle n = 53) were screened for Anaplasmataceae using 16S rRNA partial gene amplification followed by species confirmation using phylogenetic analysis. Out of the 100 samples, Anaplasma species were detected in 7% (4/57) of the cattle and 24% (10/43) of the sable antelope samples. Of the 14 positive samples, five were determined to be A. marginale (four from cattle and one from sable), seven were A. ovis (sable) and two were A. platys (sable). Phylogenetic analysis of the 16S rRNA partial gene sequences revealed genetic proximity between A. ovis and A. marginale, regardless of host. The detection of Anaplasma in wildlife in Zambia shows the risk of transmission of Anaplasma species associated with wildlife translocation.
Asunto(s)
Antílopes , Mustelidae , Humanos , Animales , Bovinos , Ovinos , Anaplasma/genética , ARN Ribosómico 16S/genética , Zambia/epidemiología , FilogeniaRESUMEN
Although rabies is endemic in Malawi, there have been no studies in which rabies virus was systematically investigated and characterized in multiple animal hosts in that country. In order to provide molecular epidemiological data on rabies virus in Malawi, 683 suspected rabies case reports from 2008 to 2021 were examined, and 46 (dog = 40, cow = 5, and cat = 1) viable rabies-positive brain samples archived at the Central Veterinary Laboratory (CVL), Lilongwe, Malawi, were analyzed genetically. The results showed an increase in the submission of brain samples from 2008 to 2010, with the highest number of submissions observed in 2020. Of the 683 case reports analyzed for the period under review, 38.1% (260/683) (CI: 34.44 - 41.84) were confirmed by direct fluorescent antibody test. Among the confirmed cases, 65.4% (170/260) (CI: 59.23 - 71.09) were canine rabies. Further, phylogenetic analysis revealed that sequences from different animal hosts clustered together within the Africa 1b lineage, suggesting that the strains circulating in livestock are similar to those in domestic dogs. This finding supports the hypothesis that canine rabies is spilling over to livestock and emphasizes the need for further studies to provide data for effective control of rabies in Malawi.
Asunto(s)
Enfermedades de los Perros , Virus de la Rabia , Rabia , Femenino , Bovinos , Animales , Perros , Virus de la Rabia/genética , Rabia/epidemiología , Rabia/veterinaria , Filogenia , Malaui/epidemiología , Epidemiología Molecular , Enfermedades de los Perros/epidemiología , GanadoRESUMEN
Human African trypanosomiasis (HAT) is a neglected tropical disease that has not received much attention in Zambia and most of the countries in which it occurs. In this study, we assessed the adequacy of the healthcare delivery system in diagnosis and management of rHAT cases, the environmental factors associated with transmission, the population at risk and the geographical location of rHAT cases. Structured questionnaires, focus group discussions and key informant interviews were conducted among the affected communities and health workers. The study identified 64 cases of rHAT, of which 26 were identified through active surveillance and 38 through passive surveillance. We identified a significant association between knowledge of the vector for rHAT and knowledge of rHAT transmission (p < 0.028). In all four districts, late or poor diagnosis occurred due to a lack of qualified laboratory technicians and diagnostic equipment. This study reveals that the current Zambian healthcare system is not able to adequately handle rHAT cases. Targeted policies to improve staff training in rHAT disease detection and management are needed to ensure that sustainable elimination of this public health problem is achieved in line with global targets.
RESUMEN
Insect symbionts have attracted attention for their potential use as anti-parasitic gene products in arthropod disease vectors. While tsetse species of the Luangwa valley have been extensively studied, less is known about the prevalence of symbionts and their interactions with the trypanosome parasite. Polymerase chain reaction was used to investigate the presence of Wolbachia and Sodalis bacteria, in tsetse flies infected with trypanosomes (Trypanosoma vivax, Trypanosoma congolense and Trypanosoma brucei). Out of 278 captured tsetse flies in eastern Zambia, 95.3% (n = 265, 95% CI = 92.897.8) carried endosymbionts: Wolbachia (79.1%, 95% CI 73.983.8) and Sodalis (86.3%, 95% CI 81.790.1). Overall, trypanosome prevalence was 25.5% (n = 71, 95% CI = 20.430.7), 10.8% (n = 30, 95% CI 7.114.4) for T. brucei, 1.4% (n = 4, 95% CI = 0.43.6) for both T. congolense and T. vivax, and 0.7% (n = 2, 95% CI 0.12.6) for T. b. rhodesiense. Out of 240 tsetse flies that were infected with Sodalis, trypanosome infection was reported in 40 tsetse flies (16.7%, 95% CI = 12.021.4) while 37 (16.8%, 95% CI 11.921.8) of the 220 Wolbachia infected tsetse flies were infected with trypanosomes. There was 1.3 times likelihood of T. brucei infection to be present when Wolbachia was present and 1.7 likelihood of T. brucei infection when Sodalis was present. Overall findings suggest absence of correlation between the presence of tsetse endosymbionts and tsetse with trypanosome infection. Lastly, the presence of pathogenic trypanosomes in tsetse species examined provided insights into the risk communities face, and the importance of African trypanosomiasis in the area.
Asunto(s)
Trypanosoma , Tripanosomiasis Africana , Moscas Tse-Tse , Wolbachia , Animales , Enterobacteriaceae/genética , Insectos Vectores/parasitología , Prevalencia , Trypanosoma/genética , Tripanosomiasis Africana/parasitología , Moscas Tse-Tse/parasitología , Wolbachia/genética , Zambia/epidemiologíaRESUMEN
East Coast Fever (ECF), caused by Theileria parva, is a major constraint to improved livestock keeping in east and central Africa, including Zambia. To understand the dynamics and determine the candidates for immunization in Zambia's Chongwe and Chisamba districts, a combination of Tp1 and Tp2 gene sequencing and microsatellite analysis using nine markers was conducted from which an abundance of Muguga, Kiambu, Serengeti and Katete epitopes in the field samples was obtained. Phylogenetic analysis showed six (Tp1) and three (Tp2) clusters with an absence of geographical origin clustering. The majority of haplotypes were related to Muguga, Kiambu, Serengeti and Katete, and only a few were related to Chitongo. Both antigens showed purifying selection with an absence of positive selection sites. Furthermore, low to moderate genetic differentiation was observed among and within the populations, and when vaccine stocks were compared with field samples, Chongwe samples showed more similarity to Katete and less to Chitongo, while Chisamba samples showed similarity to both Katete and Chitongo and not to Muguga, Kiambu or Serengeti. We conclude that the use of Katete stock for immunization trials in both Chongwe and Chisamba districts might produce desirable protection against ECF.
RESUMEN
Members of the genus Borrelia are arthropod-borne spirochetes that are human and animal pathogens. Vertebrate hosts, including wild animals, are pivotal to the circulation and maintenance of Borrelia spirochetes. However, information on Borrelia spirochetes in vertebrate hosts in Zambia is limited. Thus, we aimed to investigate the presence of Borrelia spirochetes in wild animals and cattle in Zambia. A total of 140 wild animals of four species and 488 cattle DNA samples from /near the Kafue National Park were collected for real-time PCR screening, followed by characterization using three different genes with positive samples. Five impalas and 20 cattle tested positive using real-time PCR, and sequence analysis revealed that the detected Borrelia were identified to be Borrelia theileri, a causative agent of bovine borreliosis. This is the first evidence of Borrelia theileri in African wildlife and cattle in Zambia. Our results suggest that clinical differentiation between bovine borreliosis and other bovine diseases endemic in Zambia is required for better treatment and control measures. As this study only included wild and domestic animals in the Kafue ecosystem, further investigations in other areas and with more wildlife and livestock species are needed to clarify a comprehensive epidemiological status of Borrelia theileri in Zambia.
RESUMEN
BACKGROUND: Tsetse flies (Diptera: Glossinidae) transmit trypanosomiasis (sleeping sickness in humans and nagana in livestock). Several studies have indicated that age, sex, site of capture, starvation and microbiome symbionts, among others, are important factors that influence trypanosome infection in tsetse flies. However, reasons for a higher infection rate in females than in males still largely remain unknown. Considering that tsetse species and sexes of larger body size are the most mobile and the most available to stationary baits, it was hypothesized in this study that the higher trypanosome prevalence in female than in male tsetse flies was a consequence of females being larger than males. METHODS: Black screen fly rounds and Epsilon traps were used to collect tsetse flies in eastern Zambia. Measurement of wing vein length and examination for presence of trypanosomes in the flies were carried out by microscopy. Principal component method was carried out to assess the potential of wing vein length as a predictor variable. The multilevel binary logistic regression method was applied on whole data, one-method data and one-sex data sets to evaluate the hypothesis. RESULTS: Data derived from a total of 2195 Glossina morsitans morsitans were evaluated (1491 males and 704 females). The wing length variable contributed the highest variance percentage (39.2%) to the first principal component. The variable showed significant influence on prevalence of trypanosomes when the analysis was applied on the whole data set, with the log odds for the prevalence of trypanosomes significantly increasing by 0.1 (P = 0.032), per unit increase in wing length. Females had higher trypanosome prevalence rates than males, though not always significant. Furthermore, moving from females to males, wing length significantly reduced by 0.2 (P < 0.0001). CONCLUSIONS: We conclude that wing length is an important predictor variable for trypanosome prevalence in Glossina morsitans morsitans and could partially explain the higher prevalence of trypanosomes in females than in males. However, reasonably representative population data are required for analysis-a serious challenge with the current tsetse sampling methods. Thus, analysis combining data from mobile and stationary methods that include both sexes' data could be useful to verify this hypothesis.
Asunto(s)
Insectos Vectores/parasitología , Tripanosomiasis/epidemiología , Moscas Tse-Tse/anatomía & histología , Moscas Tse-Tse/parasitología , Alas de Animales , Animales , Tamaño Corporal , Femenino , Insectos Vectores/anatomía & histología , Masculino , Prevalencia , Factores Sexuales , Tripanosomiasis/transmisión , Zambia/epidemiologíaRESUMEN
Rickettsia asembonensis is a flea-related Rickettsia with unknown pathogenicity to humans. We detected R. asembonensis DNA in 2 of 1,153 human blood samples in Zambia. Our findings suggest the possibility of R. asembonensis infection in humans despite its unknown pathogenicity.
Asunto(s)
Infecciones por Rickettsia , Rickettsia felis , Rickettsia , Siphonaptera , Animales , Humanos , Rickettsia/genética , Infecciones por Rickettsia/diagnóstico , Infecciones por Rickettsia/epidemiología , Zambia/epidemiologíaRESUMEN
African trypanosomes cause diseases in humans and livestock. Human African trypanosomiasis is caused by Trypanosoma brucei rhodesiense and T. b. gambiense. Animal trypanosomoses have major effects on livestock production and the economy in developing countries, with disease management depending mainly on chemotherapy. Moreover, only few drugs are available and these have adverse effects on patients, are costly, show poor accessibility, and parasites develop drug resistance to them. Therefore, novel trypanocidal drugs are urgently needed. Here, the effects of synthesized nitrofurantoin analogs were evaluated against six species/strains of animal and human trypanosomes, and the treatment efficacy of the selected compounds was assessed in vivo. Analogs 11 and 12, containing 11- and 12-carbon aliphatic chains, respectively, showed the highest trypanocidal activity (IC50 < 0.34 µM) and the lowest cytotoxicity (IC50 > 246.02 µM) in vitro. Structure-activity relationship analysis suggested that the trypanocidal activity and cytotoxicity were related to the number of carbons in the aliphatic chain and electronegativity. In vivo experiments, involving oral treatment with nitrofurantoin, showed partial efficacy, whereas the selected analogs showed no treatment efficacy. These results indicate that nitrofurantoin analogs with high hydrophilicity are required for in vivo assessment to determine if they are promising leads for developing trypanocidal drugs.
Asunto(s)
Nitrofuranos/administración & dosificación , Nitrofuranos/síntesis química , Nitrofurantoína/análogos & derivados , Tripanocidas/administración & dosificación , Tripanocidas/síntesis química , Tripanosomiasis Africana/tratamiento farmacológico , Administración Oral , Animales , Línea Celular , Modelos Animales de Enfermedad , Femenino , Ratones , Estructura Molecular , Nitrofuranos/química , Nitrofuranos/farmacología , Relación Estructura-Actividad , Tripanocidas/química , Tripanocidas/farmacología , Trypanosoma brucei gambiense/efectos de los fármacos , Trypanosoma brucei rhodesiense/efectos de los fármacosRESUMEN
Theileria parva (T. parva) is a protozoan parasite that causes East Coast fever (ECF). The disease is endemic in Burundi and is a major constraint to livestock development. In this study, the parasite prevalence in cattle in six regions namely; Northern, Southern, Eastern, Western, Central and North Eastern was estimated. Furthermore, the sequence diversity of p67, Tp1 and Tp2 genes was assessed coupled with the population genetic structure of T. parva using five satellite markers. The prevalence of ECF was 30% (332/1109) on microscopy, 60% (860/1431) on ELISA and 79% (158/200) on p104 gene PCR. Phylogenetic analysis of p67 gene revealed that only allele 1 was present in the field samples. Furthermore, phylogenetic analysis of Tp1 and Tp2 showed that the majority of samples clustered with Muguga, Kiambu and Serengeti and shared similar epitopes. On the other hand, genetic analysis revealed that field samples shared only two alleles with Muguga Cocktail. The populations from the different regions indicated low genetic differentiation (FST = 0.047) coupled with linkage disequilibrium and non-panmixia. A low to moderate genetic differentiation (FST = 0.065) was also observed between samples and Muguga cocktail. In conclusion, the data presented revealed the presence of a parasite population that shared similar epitopes with Muguga Cocktail and was moderately genetically differentiated from it. Thus, use of Muguga Cocktail vaccine in Burundi is likely to confer protection against T. parva in field challenge trials.
Asunto(s)
Bovinos/parasitología , Theileria parva/genética , Theileriosis/parasitología , Animales , Burundi , Variación Genética , Desequilibrio de Ligamiento , Repeticiones de Microsatélite , Filogenia , Vacunas Antiprotozoos/uso terapéutico , Theileriosis/prevención & control , Vacunación/veterinariaRESUMEN
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.
RESUMEN
We clarified the genetic diversity of Trypanosoma spp. within the Kafue ecosystem, using PCR targeting the internal transcribed spacer 1 and the cathepsin L-like cysteine protease (CatL) sequences. The overall prevalence of Trypanosoma spp. in cattle and tsetse flies was 12.65 and 26.85%, respectively. Cattle positive for Trypanosoma vivax had a significantly lower packed cell volume, suggesting that T. vivax is the dominant Trypanosoma spp. causing anemia in this area. Among the 12 operational taxonomic units (OTUs) of T. vivax CatL sequences detected, one was from a known T. vivax lineage, two OTUs were from known T. vivax-like lineages, and nine OTUs were considered novel T. vivax-like lineages. These findings support previous reports that indicated the extensive diversity of T. vivax-like lineages. The findings also indicate that combining CatL PCR with next generation sequencing is useful in assessing Trypanosoma spp. diversity, especially for T. vivax and T. vivax-like lineages. In addition, the 5.42% prevalence of Trypanosoma brucei rhodesiense found in cattle raises concern in the community and requires careful monitoring of human African trypanosomiasis.
RESUMEN
The capacity to detect, control and manage emerging and re-emerging zoonotic diseases in Africa has been limited by a lack of utilisation of available reporting structures and policies to support programmes at national and local levels. This study explored the impact of the Zambian government policies on animal and human disease reporting and management and on One Health opportunities. An in-depth review and analysis of strengths, weaknesses, opportunities, and threats in the existing policies and reporting structures in the departments responsible for Veterinary Services, Health, and Wildlife, was conducted. According to our findings, sub-optimal implementation of existing policies related to the control of zoonotic diseases was impacting disease reporting, and reporting structures play an important role in effective and sustainable reporting of zoonotic diseases. Further, the study explored capacities and strategies in trypanosomiasis control as a case study that could prompt effective adoption of a One Health approach, and as such, the study suggests measures that could help to assess the performance of a One Health system in the control of African trypanosomiasis and other zoonotic diseases.
RESUMEN
BACKGROUND: Piroplasms are vector-borne intracellular hemoprotozoan parasites that infect wildlife and livestock. Wildlife species are reservoir hosts to a diversity of piroplasms and play an important role in the circulation, maintenance and evolution of these parasites. The potential for likely spillover of both pathogenic and non-pathogenic piroplasm parasites from wildlife to livestock is underlined when a common ecological niche is shared in the presence of a competent vector. METHOD: To investigate piroplasm diversity in wildlife and the cattle population of the greater Kafue ecosystem, we utilized PCR to amplify the 18S rRNA V4 hyper-variable region and meta-barcoding strategy using the Illumina MiSeq sequencing platform and amplicon sequence variant (ASV)-based bioinformatics pipeline to generate high-resolution data that discriminate sequences down to a single nucleotide difference. RESULTS: A parasite community of 45 ASVs corresponding to 23 species consisting of 4 genera of Babesia, Theileria, Hepatozoon and Colpodella, were identified in wildlife and the cattle population from the study area. Theileria species were detected in buffalo, impala, hartebeest, sable antelope, sitatunga, wild dog and cattle. In contrast, Babesia species were only observed in cattle and wild dog. Our results demonstrate possible spillover of these hemoprotozoan parasites from wildlife, especially buffalo, to the cattle population in the wildlife-livestock interface. CONCLUSION: We demonstrated that the deep amplicon sequencing of the 18S rRNA V4 hyper-variable region for wildlife was informative. Our results illustrated the diversity of piroplasma and the specificity of their hosts. They led us to speculate a possible ecological cycle including transmission from wildlife to domestic animals in the greater Kafue ecosystem. Thus, this approach may contribute to the establishment of appropriate disease control strategies in wildlife-livestock interface areas.
Asunto(s)
Alveolados/aislamiento & purificación , Animales Salvajes/parasitología , Infecciones Protozoarias en Animales/parasitología , Alveolados/clasificación , Alveolados/genética , Animales , Animales Salvajes/clasificación , Biodiversidad , Búfalos/parasitología , Bovinos , Enfermedades de los Bovinos/parasitología , Enfermedades de los Perros/parasitología , Perros , Filogenia , Infecciones Protozoarias en Animales/epidemiología , Zambia/epidemiologíaRESUMEN
Spotted fever group (SFG) rickettsiae causes febrile illness in humans worldwide. Since SFG rickettsiosis's clinical presentation is nonspecific, it is frequently misdiagnosed as other febrile diseases, especially malaria, and complicates proper treatment. Aiming at rapid, simple, and simultaneous detection of SFG Rickettsia spp. and Plasmodium spp., we developed a novel multiple pathogen detection system by combining a loop-mediated isothermal amplification (LAMP) method and dipstick DNA chromatography technology. Two primer sets detecting SFG Rickettsia spp. and Plasmodium spp. were mixed, and amplified products were visualized by hybridizing to dipstick DNA chromatography. The multiplex LAMP with dipstick DNA chromatography distinguished amplified Rickettsia and Plasmodium targeted genes simultaneously. The determined sensitivity using synthetic nucleotides was 1000 copies per reaction for mixed Rickettsia and Plasmodium genes. When genomic DNA from in vitro cultured organisms was used, the sensitivity was 100 and 10 genome equivalents per reaction for Rickettsia monacensis and Plasmodium falciparum, respectively. Although further improvement will be required for more sensitive detection, our developed simultaneous diagnosis technique will contribute to the differential diagnosis of undifferentiated febrile illness caused by either SFG Rickettsia spp. or Plasmodium spp. in resource-limited endemic areas. Importantly, this scheme is potentially versatile for the simultaneous detection of diverse infectious diseases.
RESUMEN
Human African trypanosomiasis (HAT) is one of the neglected tropical diseases in sub-Saharan Africa. Early diagnosis and treatment prior to disease progression are crucial for the survival of HAT patients. We had previously established a loop-mediated isothermal amplification (LAMP) method for HAT diagnosis in which the reagents were dried for field-use purposes. In this study, we used a semi-automated process to produce the test tubes using a bio-inkjet printer to achieve an accurate production. The performance of the inkjet printer-produced dried LAMP test (CZC-LAMP) was found to be stable after storage for up to 180 days at 30 °C. The diagnostic accuracy of CZC-LAMP HAT was evaluated using DNA samples that were extracted from 116 Trypanosoma brucei gambiense patients and 66 T. b. rhodesiense patients. The sensitivity was 72% for T. b. gambiense (95%CI: 63%-80%) and 80% for T. b. rhodesiense (95%CI: 69%-89%). The specificity determined using DNA from 116 endemic control DNA samples was 95% (95%CI: 89%-98%). The performance of the CZC-LAMP HAT and CZC-LAMP rHAT were also evaluated using 14 crude blood lysate samples obtained from T. b. rhodesiense patients and endemic control samples collected from Rumphi District in Malawi. The sensitivity and specificity were both 100% (95%CI: 77%-100%). As the developed CZC-LAMP test does not require a cold chain or a sophisticated laboratory, it holds promise for use as a routine simple molecular tool for point-of-care HAT diagnosis in endemic areas.
Asunto(s)
Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Trypanosoma brucei gambiense/aislamiento & purificación , Trypanosoma brucei rhodesiense/aislamiento & purificación , Tripanosomiasis Africana/diagnóstico , Animales , ADN Protozoario/análisis , Humanos , Malaui , Sistemas de Atención de Punto , Sensibilidad y Especificidad , Trypanosoma brucei gambiense/genética , Trypanosoma brucei rhodesiense/genéticaRESUMEN
BACKGROUND: East Coast fever (ECF) caused by Theileria parva is endemic in Rwanda. In this study, the antigenic and genetic diversity of T. parva coupled with immunization and field challenge were undertaken to provide evidence for the introduction of ECF immunization in Rwanda. METHODS: Blood collected from cattle in the field was screened for T. parva using ELISA and PCR targeting the p104 gene. Tp1 and Tp2 gene sequences were generated from field samples and from Gikongoro and Nyakizu isolates. Furthermore, multilocus genotype data was generated using 5 satellite markers and an immunization challenge trial under field conditions using Muguga cocktail vaccine undertaken. RESULTS: Out of 120 samples, 44 and 20 were positive on ELISA and PCR, respectively. Antigenic diversity of the Tp1 and Tp2 gene sequences revealed an abundance of Muguga, Kiambu and Serengeti epitopes in the samples. A further three clusters were observed on both Tp1 and Tp2 phylogenetic trees; two clusters comprising of field samples and vaccine isolates and the third cluster comprising exclusively of Rwanda samples. Both antigens exhibited purifying selection with no positive selection sites. In addition, satellite marker analysis revealed that field samples possessed both shared alleles with Muguga cocktail on all loci and also a higher proportion of unique alleles. The Muguga cocktail (Muguga, Kiambu and Serengeti) genotype compared to other vaccine isolates, was the most represented in the field samples. Further low genetic sub-structuring (FST = 0.037) coupled with linkage disequilibrium between Muguga cocktail and the field samples was observed. Using the above data to guide a field immunization challenge trial comprising 41 immunized and 40 control animals resulted in 85% seroconversion in the immunized animals and an efficacy of vaccination of 81.7%, implying high protection against ECF. CONCLUSIONS: Antigenic and genetic diversity analysis of T. parva facilitated the use of Muguga cocktail vaccine in field conditions. A protection level of 81.7% was achieved, demonstrating the importance of combining molecular tools with field trials to establish the suitability of implementation of immunization campaigns. Based on the information in this study, Muguga cocktail immunization in Rwanda has a potential to produce desirable results.
Asunto(s)
Antígenos de Protozoos/inmunología , ADN Satélite/genética , Inmunización/veterinaria , Theileria parva , Theileriosis , Animales , Variación Antigénica , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/prevención & control , Ensayo de Inmunoadsorción Enzimática/veterinaria , Genes Protozoarios , Marcadores Genéticos , Variación Genética , Filogenia , Reacción en Cadena de la Polimerasa/veterinaria , Polimorfismo Genético , Vacunas Antiprotozoos/inmunología , Rwanda , Linfocitos T/inmunología , Theileria parva/genética , Theileria parva/inmunología , Theileriosis/inmunología , Theileriosis/prevención & control , Vacunación/veterinariaRESUMEN
Tsetse transmitted trypanosomiasis is a fatal disease commonly known as Nagana in cattle and sleeping sickness in humans. The disease threatens food security and has severe economic impact in Africa including most parts of Zambia. The level of effectiveness of commonly used African trypanosomiasis control methods has been reported in several studies. However, there have been no review studies on African trypanosomiasis control and management conducted in the context of One Health. This paper therefore seeks to fill this knowledge gap. A review of studies that have been conducted on African trypanosomiasis in Zambia between 2009 and 2019, with a focus on the control and management of trypanosomiasis was conducted. A total of 2238 articles were screened, with application of the search engines PubMed, PubMed Central and One Search. Out of these articles, 18 matched the required criteria and constituted the basis for the paper. An in-depth analysis of the 18 articles was conducted to identify knowledge gaps and evidence for best practices. Findings from this review provide stakeholders and health workers with a basis for prioritisation of African trypanosomiasis as an important neglected disease in Zambia and for formulation of One Health strategies for better control and/or management of the disease.
RESUMEN
The Kafue ecosystem is a vast conservation protected area comprising the Kafue National Park (KNP) and the Game Management Areas (GMA) that act as a buffer around the national park. The KNP has been neglected as a potential foci for rhodesiense sleeping sickness despite the widespread presence of the tsetse vector and abundant wildlife reservoirs. The aim of this study was to generate information on circulating trypanosomes and their eminent threat/risk to public health and livestock production of a steadily growing human and livestock population surrounding the park. We detected various trypanosomes circulating in different mammalian wildlife species in KNP in Zambia by applying a high throughput ITS1-polymerase chain reaction (PCR)/nanopore sequencing method in combination with serum resistant associated-PCR/Sanger sequencing method. The prevalence rates of trypanosomes in hartebeest, sable antelope, buffalo, warthog, impala and lechwe were 6.4%, 37.2%, 13.2%, 11.8%, 2.8% and 11.1%, respectively. A total of six trypanosomes species or subspecies were detected in the wildlife examined, including Trypanosoma brucei brucei, T. godfreyi, T. congolense, T. simiae and T. theileri. Importantly we detected human infective T. b. rhodesiense in buffalo and sable antelope with a prevalence of 9.4% and 12.5%, respectively. In addition, T. b. rhodesiense was found in the only vervet monkey analyzed. The study thus reaffirmed that the Kafue ecosystem is a genuine neglected and re-emerging foci for human African trypanosomiasis. This is the first assessment of the trypanosome diversity circulating in free-ranging wildlife of the KNP.