Cross border transhumance involvement in ticks and tick-borne pathogens dissemination and first evidence of Anaplasma centrale in Burkina Faso

Ticks (Acari: Ixodidae) infesting cattle in coastal Kenya harbor a diverse array of tick-borne pathogens

Ticks and the microbes they transmit have emerged in sub-Saharan Africa as a major threat to veterinary and public health. Although progress has been made in detecting and identifying tick-borne pathogens (TBPs) across vast agroecologies of Kenya, comprehensive information on tick species infesting cattle and their associated pathogens in coastal Kenya needs to be updated and expanded. Ticks infesting extensively grazed zebu cattle in 14 villages were sampled and identified based on morphology and molecular methods and tested for the presence of bacterial and protozoan TBPs using PCR with high-resolution melting analysis and gene sequencing. In total, 3,213 adult ticks were collected and identified as Rhipicephalus appendiculatus (15.8%), R. evertsi (12.8%), R. microplus (11.3%), R. pulchellus (0.1%), Amblyomma gemma (24.1%), A. variegatum (35.1%), Hyalomma rufipes (0.6%), and H. albiparmatum (0.2%). Ticks were infected with Rickettsia africae, Ehrlichia ruminantium, E. minasensis, Theileria velifera and T. parva. Coxiella sp. endosymbionts were detected in the Rhipicephalus and Amblyomma ticks. Co-infections with two and three different pathogens were identified in 6.9% (n = 95/1382) and 0.1% (n = 2/1382) of single tick samples, respectively, with the most common co-infection being R. africae and E. ruminantium (7.2%, CI: 4.6 - 10.6). All samples were negative for Coxiella burnetii, Anaplasma spp. and Babesia spp. Our study provides an overview of tick and tick-borne microbial diversities in coastal Kenya.

Tick-Borne Diseases of Humans and Animals in West Africa

Ticks are a significant group of arthropod vectors that transmit a large variety of pathogens responsible for human and animal diseases worldwide. Ticks are the second biggest transmitters of vector-borne diseases, behind mosquitoes. However, in West Africa, there is often only limited knowledge of tick-borne diseases. With the scarcity of appropriate diagnostic services, the prevalence of tick-borne diseases is generally underestimated in humans. In this review, we provide an update on tick-borne pathogens reported in people, animals and ticks in West Africa by microscopic, immunological and molecular methods. A systematic search was conducted in PubMed and Google Scholar. The selection criteria included all studies conducted in West Africa reporting the presence of Rickettsia, Borrelia, Anaplasma, Ehrlichia, Bartonella, Coxiella burnetii, Theileria, Babesia, Hepatozoon and Crimean-Congo haemorrhagic fever viruses in humans, animals or ticks. Our intention is to raise awareness of tick-borne diseases amongst human and animal health workers in West Africa, and also physicians working with tourists who have travelled to the region.

Molecular survey of Anaplasma and Ehrlichia species in livestock ticks from Kassena-Nankana, Ghana; with a first report of Anaplasma capra and Ehrlichia minasensis

Tick-borne pathogens harm livestock production and pose a significant risk to public health. To combat these effects, it is necessary to identify the circulating pathogens to create effective control measures. This study identified Anaplasma and Ehrlichia species in ticks collected from livestock in the Kassena-Nankana Districts between February 2020 and December 2020. A total of 1550 ticks were collected from cattle, sheep and goats. The ticks were morphologically identified, pooled and screened for pathogens using primers that amplify a 345 bp fragment of the 16SrRNA gene and Sanger sequencing. The predominant tick species collected was Amblyomma variegatum (62.98%). From the 491 tick pools screened, 34 (6.92%) were positive for Ehrlichia and Anaplasma. The pathogens identified were Ehrlichia canis (4.28%), Ehrlichia minasensis (1.63%), Anaplasma capra (0.81%) and Anaplasma marginale (0.20%). This study reports the first molecular identification of the above-mentioned Ehrlichia and Anaplasma species in ticks from Ghana. With the association of human infections with the zoonotic pathogen A. capra, livestock owners are at risk of infections, calling for the development of effective control measures.