Molecular identification and prevalence of tick-borne pathogens in zebu and taurine cattle in North Cameroon.

Public interest for tick-borne pathogens in cattle livestock is rising due to their veterinary and zoonotic importance. Consequently, correct identification of these potential pathogens is crucial to estimate the level of exposition, the risk and the detrimental impact on livestock and the human population. Conventional PCR with generic primers was used to identify groups of tick-borne pathogens in cattle breeds from northern Cameroon. The overall prevalence in 1260 blood samples was 89.1%, with 993 (78.8%) positive for Theileria/Babesia spp., 959 (76.1%) for Anaplasma/Ehrlichia spp., 225 (17.9%) for Borrelia spp., and 180 (14.3%) for Rickettsia spp. Sanger sequencing of a subset of positively-tested samples revealed the presence of Theileria mutans (92.2%, 130/141), T. velifera (16.3%, 23/141), Anaplasma centrale (10.9%, 15/137), A. marginale (30.7%, 42/137), A. platys (51.1%, 70/137), Anaplasma sp. 'Hadesa' (10.9%, 15/137), Ehrlichia ruminantium (0.7%, 1/137), E. canis (0.7%, 1/137), Borrelia theileri (91.3%, 42/46), Rickettsia africae (59.4%, 19/32) and R. felis (12.5%, 4/32). A high level of both intra- and inter-generic co-infections (76.0%) was observed. To the best of our knowledge, B. theileri, T. mutans, T. velifera, A. platys, Anaplasma sp. 'Hadesa', R. felis and E. canis are reported for the first time in cattle from Cameroon, and for R. felis it is the first discovery in the cattle host. Babesia spp. were not detected by sequencing. The highest number of still identifiable species co-infections was up to four pathogens per genus group. Multifactorial analyses revealed a significant association of infection with Borrelia theileri and anemia. Whereas animals of older age had a higher risk of infection, the Gudali cattle had a lower risk compared to the other local breeds. Co-infections of tick-borne pathogens with an overall high prevalence were found in all five study sites, and were more likely to occur than single infections. Fulani, Namchi and Kapsiki were the most infected breed in general; however, with regions as significant risk factor. A better-adapted approach for tick-borne pathogen identification in co-infected samples is a requirement for epidemiological investigations and tailored control measures.

Abanda B ，Paguem A ，Abdoulmoumini M ，Kingsley MT ，Renz A ，Eisenbarth A ... -  《Parasites & Vectors》

Molecular prevalence and risk factors associated with tick-borne pathogens in cattle in western Kenya.

Tick-borne pathogens (TBPs) are of global importance, especially in sub-Saharan Africa where they represent a major constraint to livestock production. Their association with human disease is also increasingly recognized, signalling their zoonotic importance. It is therefore crucial to investigate TBPs prevalence in livestock populations and the factors associated with their presence. We set out to identify TBPs present in cattle and to determine associated risk factors in western Kenya, where smallholder livestock production is important for subsistence and market-driven income. Tick-borne pathogen infections in blood samples collected from cattle at livestock markets and slaughterhouses between May 2017 and January 2019 were identified by high-resolution melting analysis and sequencing of PCR products of genus-specific primers. Of the 422 cattle sampled, 30.1% (127/422) were infected with at least one TBP, while 8.8% (37/422) had dual infections. Anaplasma spp. (19.7%) were the most prevalent, followed by Theileria (12.3%), Ehrlichia (6.6%), and Babesia (0.2%) spp. Sequence analysis of the TBPs revealed them to be Anaplasma platys-like organisms (13.5%), Theileria velifera (7.4%), Anaplasma marginale (4.9%), Theileria mutans (3.1%), Theileria parva (1.6%), and Babesia bigemina (0.2%). Ehrlichia ruminantium, Rickettsia spp., and arboviruses were not detected. Exotic breeds of cattle were more likely to be infected with A. marginale compared to local breeds (OR: 7.99, 95% CI: 3.04-22.02, p <  0.001). Presence of ticks was a significant predictor for Anaplasma spp. (OR: 2.18, 95% CI: 1.32-3.69, p = 0.003) and Ehrlichia spp. (OR: 2.79, 95% CI: 1.22-7.23, p = 0.022) infection. Cattle sampled at slaughterhouses were more likely to be positive for Anaplasma spp. (OR: 1.64, 95% CI: 1.01-2.70, p = 0.048) and A. marginale (OR: 3.84, 95% CI: 1.43-12.21, p = 0.012), compared to those sampled at livestock markets. This study reports TBP prevalence and associated risk factors in western Kenya, factors which are key to informing surveillance and control measures.

Chiuya T ，Villinger J ，Masiga DK ，Ondifu DO ，Murungi MK ，Wambua L ，Bastos ADS ，Fèvre EM ，Falzon LC ... -  《-》

Tick-borne pathogens of zoonotic and veterinary importance in Nigerian cattle.

Ticks and tick-borne diseases undermine cattle fitness and productivity in the whole of sub-Saharan Africa, including Nigeria. In this West African country, cattle are challenged by numerous tick species, especially during the wet season. Consequently, several TBDs are known to be endemic in Nigerian cattle, including anaplasmosis, babesiosis, cowdriosis and theilerioris (by Theileria mutans and Theileria velifera). To date, all investigations on cattle TBDs in Nigeria have been based on cytological examinations and/or on serological methods. This study aimed to ascertain the occurrence of tick-borne pathogens of veterinary and zoonotic importance in cattle in Nigeria using molecular approaches. In October 2008, 704 whole blood samples were collected from indigenous cattle in the Plateau State, Nigeria. Analysis for tick-borne pathogens was conducted by means of PCR-based reverse line blotting (RLB) and sequencing targeting a panel of five genera of microorganisms (i.e. Babesia, Theileria, Anaplasma, Ehrlichia and Rickettsia spp.). In total, 561/704 (82.6%) animals were found infected, with 465 (69.6%) of them being infected by two or more microorganisms, with up to 77 possible combinations of pathogens detected. Theileria mutans was the most prevalent microorganism (66.3%), followed by Theileria velifera (52.4%), Theileria taurotragi (39.5%), Anaplasma marginale (39.1%), Anaplasma sp. (Omatjenne) (34.7%), Babesia bigemina (7.9%), Anaplasma centrale (6.3%), Anaplasma platys (3.9%), Rickettsia massiliae (3.5%), Babesia bovis (2.0%) and Ehrlichia ruminantium (1.1%). Calves were found significantly less infected than juvenile and adult cattle. This study provides updated, molecular-based information on cattle TBDs in Nigeria. The molecular approach employed allowed the diagnosis of numerous positive cases including carrier statuses, multiple infections and novel pathogen detections within the indigenous cattle population. Moreover, the RLB method here described enabled the detection of veterinary agents not only pertaining to bovine health, including also those of zoonotic importance. The high prevalence recorded for T. mutans, T. velifera, A. marginale, T. taurotragi and Anaplasma sp. (Omatjenne), suggests they may be endemically established in Nigeria, whereas the lower prevalence recorded for other microorganisms (i.e. A. centrale and B. bovis) highlights a less stable epidemiological scenario, requiring further investigations.

Lorusso V ，Wijnveld M ，Majekodunmi AO ，Dongkum C ，Fajinmi A ，Dogo AG ，Thrusfield M ，Mugenyi A ，Vaumourin E ，Igweh AC ，Jongejan F ，Welburn SC ，Picozzi K ... -  《-》

Molecular detection of tick-borne pathogens in cattle from Southwestern Ethiopia.

Tick-borne diseases (TBDs) cause significant losses among livestock and impact the livelihoods of resource-poor farming communities worldwide. In Ethiopia, detailed studies on the epidemiology of tick-borne pathogens (TBPs) in cattle using sensitive molecular detection methods are scarce. The objective of this study was to determine the prevalence and species composition of bovine TBPs of veterinary significance in local cattle populations. A comprehensive cross-sectional epidemiological study was conducted in cattle populations of Illubabor zone in Southwestern Ethiopia from June to August 2013. For this purpose, blood samples were collected from 392 cattle. A combination of polymerase chain reaction (PCR) and a Reverse Line Blot (RLB) hybridization assay was employed for the detection of TBPs in these samples. The PCR/RLB results of the 392 blood samples indicated a high overall prevalence of 96.9% for TBPs, including Theileria mutans (66.1%), Theileria orientalis (51.8%), Anaplasma sp. Omatjenne (25.5%), Anaplasma marginale (14.5%), Babesia bigemina (14.0%) and Theileria velifera (13.0%) and minor occurrences of Ehrlichia ruminantium (0.5%) and Ehrlichia minasensis (0.26%). Moreover, three novel Anaplasma genotypes were detected in bovine blood samples. A phylogenetic analysis revealed that they most likely represent three, but at least two, new species. The prevalence of the three novel Anaplasma species, preliminary designated as Anaplasma sp. Hadesa, Anaplasma sp. Saso and Anaplasma sp. Dedessa, was 12.5%, 14.3% and 5.6%, respectively. Overall, a total of 227 cattle (57.9%) were found to be co-infected with two or more TBPs simultaneously and 86 different species combinations were observed. The findings show a very high burden of infection of cattle with TBPs in Ethiopia. The high frequency of co-infections suggests that clinical manifestations might be complex. Further research is required to determine the pathogenicity, host cell types and vector of the three novel Anaplasma species identified in this study.

Hailemariam Z ，Krücken J ，Baumann M ，Ahmed JS ，Clausen PH ，Nijhof AM ... -  《-》

Molecular detection and characterization of tick-borne protozoan and rickettsial pathogens isolated from cattle on Pemba Island, Tanzania.

Tick-borne diseases cause significant losses to livestock production in tropical and subtropical regions. In Tanzania, detailed studies on tick-borne pathogens in cattle using sensitive molecular detection methods are scarce. In this study, we investigated the occurrence of Theileria spp., Babesia spp., Anaplasma spp. and Ehrlichia spp. in 245 blood samples collected from cattle on Pemba Island, Tanzania. We used polymerase chain reaction (PCR) and gene sequencing to detect and identify pathogens. PCR screening revealed overall infection rates of 62.4% for Theileria spp., 17.6% for Babesia bigemina, 15.9% for Anaplasma marginale, 7.4% for Ehrlichia ruminantium and 4.5% for Babesia bovis. Further analysis using sequences of Theileria spp. 18S rRNA revealed infection of cattle with Theileria mutans (68.6%), Theileria taurotragi (48.4%), Theileria parva (41.2%), and Theileria ovis (1.9%). Co-infections of cattle, with up to six tick-borne pathogens, were revealed in 46.9% of the samples. Sequence analysis indicated that T. parva p104, E. ruminantium pCS20 and A. marginale MSP-5 genes are conserved among cattle blood samples in Pemba, with 99.3%-100%, 99.6%-100% and 100% sequence identity values, respectively. In contrast, the B. bigemina RAP-1a and B. bovis SBP-2 gene sequences were relatively diverse with 99.5%-99.9% and 66.4%-98.7% sequence identity values respectively. The phylogenetic analyses revealed that T. parva p104, E. ruminantium pCS20 and A. marginale MSP-5 gene sequences clustered in the same clade with other isolates from other countries. In contrast, the B. bigemina RAP-1 and B. bovis SBP-2 gene sequences showed significant differences in the genotypes, as they appeared in separate clades. This study provides important data for understanding the epidemiology of tick-borne diseases, and is expected to improve the approach for diagnosis and control of tick-borne diseases in Tanzania.

Ringo AE ，Adjou Moumouni PF ，Lee SH ，Liu M ，Khamis YH ，Gao Y ，Guo H ，Zheng W ，Efstratiou A ，Galon EM ，Li J ，Tiwananthagorn S ，Inoue N ，Suzuki H ，Thekisoe O ，Xuan X ... -  《-》