Seroprevalence of Selected Tick Borne Pathogens and Diversity and Abundance of Ixodid Ticks (Acari: Ixodidae) at the Wildlife-Livestock Interface in Northern Botswana

Identification of ticks and tick-borne pathogens of wildlife necropsy cases submitted to the SANBI National Zoological Gardens, South Africa

Ticks are arachnid blood-feeding parasites, which infest livestock, wildlife, and humans, transmitting medically and veterinary significant pathogens. Their biodiversity and distribution in wild animals remains complex. This study analysed archived tick samples (n = 48) from the South African Biodiversity Institute (SANBI) Wildlife Biobank utilizing morphology and genetic analyses of the 16S rRNA and COI (DNA barcoding) mitochondrial genes to identify ticks collected among 13 vertebratesavian, reptilian, and mammalian host species. The specimens came from nine localities including nature reserves and captive facilities (zoological garden) in South Africa, Namibia, and Botswana. These ticks were also assessed for associated pathogens with the reverse line blot (RLB) hybridization assay. Seven tick genera, Amblyomma, Hyalomma, Haemaphysalis, Ixodes, Rhipicephalus, Rhipicentor, and Otobius were identified, with Amblyomma being the most prevalent (22.9 %) in our sample set. Obtained sequences were 95-100 % similar to published records of tick species collected from wild and domestic animals, as well as those collected from vegetation, from different southern African areas. However, tick specimens (n = 3) identified morphologically as Hyalomma truncatum, Rhipicephalus e. evertsi, and R. simus, were, on a molecularly level, more closely related to their sister taxa (H. glabrum, R. e. mimeticus, and R. gertrudae, respectively) suggesting a need for taxonomic verification. With the RLB hybridization assay, six samples reacted with the Ehrlichia/Anaplasma genus-specific probe, while two reacted with the Theileria/Babesia genus-specific probe. Sequencing of the RLB amplicons targeting the 18S rRNA gene (n = 2) indicated 100 % similarity to Hepatozoon fitzsimonsi, while one was closely related to He. ingwe with 99.39 % similarity. The results show that wildlife harbour different tick species, and pathogen detection identified novel genotypes, indicating wildlife as potential pathogens reservoirs. This study enhances our understanding of tick biodiversity, distribution and highlights wildlife's role in harbouring diverse tick species and novel pathogens.

Detection of Tick-Borne Pathogens in Ticks from Cattle in Western Highlands of Cameroon

This study aimed to detect and identify microorganisms in ticks collected in the Western Highlands of Cameroon. Quantitative real-time and standard PCR assays, coupled with sequencing, were used. A total of 944 ticks collected from cattle in five distinct sites in Cameroon were selected for the analyses. They belonged to five genera (Amblyomma, Hyalomma, Rhipicephalus, Haemaphysalis, and Ixodes) and twelve species. Real-time PCR revealed that 23% (n = 218) of the ticks were positive for Rickettsia spp., 15% (n = 141) for bacteria of the Anaplasmataceae family, 3% (n = 29) for Piroplasmida, 0.5% (n = 5) for Coxiella burnetii, 0.4% (n = 4) for Borrelia spp., and 0.2% (n = 2) for Bartonella spp. The co-infection rate (3.4%, n = 32) involved mainly Rickettsia spp. and Anaplasmataceae. Of the Rickettsia spp. positive ticks, the targeted PCR and sequencing yielded Rickettsia africae (78.9%), Rickettsia aeschlimannii (6.4%), Rickettsia massiliae (7.8%), Candidatus Rickettsia barbariae (0.9%), and Rickettsia sp. (0.9%). Anaplasmataceae included Anaplasma marginale (4.3%), Anaplasma platys (1.4%), Anaplasma centrale (0.7%), Ehrlichia ruminantium (0.7%), Wolbachia sp., Candidatus Ehrlichia rustica (13.5%), Candidatus Ehrlichia urmitei (7%), and an uncultured Ehrlichia sp. (4.2%). Borrelia theileri was identified in one Rhipicephalus microplus tick. Unfortunately, Piroplasmida could not be identified to the species level. This study demonstrates that in Cameroon, ticks harbour a wide variety of microorganisms and present a risk of zoonotic diseases.

Predictive Analytics of Cattle Host and Environmental and Micro-Climate Factors for Tick Distribution and Abundance at the Livestock-Wildlife Interface in the Lower Okavango Delta of Botswana

Tick distribution and abundance is influenced by several factors that include micro-climate and environmental and host factors. Contextual understanding of the role played by these factors is critical to guide control measures. The aim of this study was to determine the predictive value of these factors for changes in tick distribution and abundance at the livestock-wildlife interface of the lower Okavango Delta. A two-stage quota sampling design was adopted to select 30 clusters of seven cattle each for tick investigation. Tick investigation was done by lifting the tail to count the total number of ticks at the anno-vulva region during the four meteorological seasons of the year. Additional data were collected on ear tag number, location of origin, sex, age, body condition score (BCS), season of the year, stocking density, and Normalized Difference Vegetation Index values of source terrain. A random effects model was used to evaluate predictive value of the above for tick abundance. Additional mapping of tick distribution pattern in the abattoir catchment area was conducted using spatial autocorrelation and hot-spot analysis. Tick intensity of infection increased linearly from males to females (Z = 3.84, p < 0.001), decreased linearly from lower to higher BCS (Z = -4.11, p < 0.001), and increased linearly from cold-dry through dry to wet seasons (Z = 10.19, p < 0.001). Significant clustering of neighboring crushes on account of tick count was noted in the late-hot-dry season, with high tick count in crushes located along the seasonal flood plains and low tick counts in those located in the dry grasslands. It was concluded from this study that cattle tick abundance is influenced largely by season of the year and that the micro-climatic conditions brought about by the seasonal flooding of the delta have a decided effect on tick distribution during the driest of the seasons. Our study has, for the first time, profiled drivers of tick distribution and population growth in this unique ecosystem. This has the potential to benefit human and veterinary public health in the area through implementation of sustainable tick control strategies that are not heavily reliant on acaricides.

A Survey of Potentially Pathogenic-Incriminated Arthropod Vectors of Health Concern in Botswana

Arthropod vectors play a crucial role in the transmission of many debilitating infections, causing significant morbidity and mortality globally. Despite the economic significance of arthropods to public health, public knowledge on vector biology, ecology and taxonomic status remains anecdotal and largely unexplored. The present study surveyed knowledge gaps regarding the biology and ecology of arthropod vectors in communities of Botswana, across all districts. Results showed that communities are largely aware of individual arthropod vectors; however, their 'potential contribution' in disease transmission in humans, livestock and wildlife could not be fully attested. As such, their knowledge was largely limited with regards to some aspects of vector biology, ecology and control. Communities were strongly concerned about the burden of mosquitoes, cockroaches, flies and ticks, with the least concerns about fleas, bedbugs and lice, although the same communities did not know of specific diseases potentially vectored by these arthropods. Knowledge on arthropod vector control was mainly limited to synthetic chemical pesticides for most respondents, regardless of their location. The limited knowledge on potentially pathogen-incriminated arthropod vectors reported here has large implications for bridging knowledge gaps on the bio-ecology of these vectors countrywide. This is potentially useful in reducing the local burden of associated diseases and preventing the risk of emerging and re-emerging infectious diseases under global change.

Ticks and Tick-Borne Pathogens Associated with Dromedary Camels (Camelus dromedarius) in Northern Kenya

Ticks and tick-borne pathogens (TBPs) are major constraints to camel health and production, yet epidemiological data on their diversity and impact on dromedary camels remain limited. We surveyed the diversity of ticks and TBPs associated with camels and co-grazing sheep at 12 sites in Marsabit County, northern Kenya. We screened blood and ticks (858 pools) from 296 camels and 77 sheep for bacterial and protozoan TBPs by high-resolution melting analysis and sequencing of PCR products. Hyalomma (75.7%), Amblyomma (17.6%) and Rhipicephalus (6.7%) spp. ticks were morphologically identified and confirmed by molecular analyses. We detected TBP DNA in 80.1% of blood samples from 296 healthy camels. "Candidatus Anaplasma camelii", "Candidatus Ehrlichia regneryi" and Coxiella burnetii were detected in both camels and associated ticks, and Ehrlichia chaffeensis, Rickettsia africae, Rickettsia aeschlimannii and Coxiella endosymbionts were detected in camel ticks. We also detected Ehrlichia ruminantium, which is responsible for heartwater disease in ruminants, in Amblyomma ticks infesting camels and sheep and in sheep blood, indicating its endemicity in Marsabit. Our findings also suggest that camels and/or the ticks infesting them are disease reservoirs of zoonotic Q fever (C. burnetii), ehrlichiosis (E. chaffeensis) and rickettsiosis (R. africae), which pose public health threats to pastoralist communities.

Tick Fauna and Associated Rickettsia, Theileria, and Babesia spp. in Domestic Animals in Sudan (North Kordofan and Kassala States)

Ticks and tick-borne diseases (TBDs) have a major economic impact on animal production worldwide. In the present study, 2410 ticks were collected from January to August 2017 from livestock and other domestic animals in North Kordofan and Kassala, Sudan, for species identification and investigation of Rickettsia spp. and piroplasms, either individually or as pools containing up to 10 ticks by molecular methods. In total, 13 tick species were identified by morphology and 16S rDNA sequencing. The most frequent tick species were Hyalomma impeltatum (24.90%), Rhipicephalus evertsi evertsi (18.84%), Amblyomma lepidum (16.06%), and Rhipicephalus camicasi (12.49%). A pan-Rickettsia real-time PCR revealed an overall minimum infection rate (MIR) with Rickettsia spp. of 5.64% (136 positive tick pools/2410 total ticks). Rickettsia africae and Rickettsia aeschlimannii were the most frequently identified species by sequencing. Furthermore, the following highly pathogenic livestock parasites were detected: Theileria annulata, Theileria lestoquardi, Theileria equi, and Babesia caballi. The present study documented Rhipicephalus afranicus as well as Rickettsia conorii israelensis, Rickettsia massiliae, and Babesia pecorum for the first time in Sudan. These findings are significant for the animal production sector as well as in terms of One Health, as the detected Rickettsia spp. can cause serious illness in humans.