Distribution and ecology of Ornithodoros phacochoerus in the coutada 9 game reserve in central Mozambique

Background Ornithodoros soft ticks of the O . moubata species complex are biological vectors of African swine fever (ASF) virus, the causative agent of ASF in domestic pigs, and vectors of Borrelia duttonii , the agent of Tick-Borne Relapsing Fever (TBRF) in humans. These ticks are nidicolous, living in subterranean warthog burrows and terrestrial shelters and can survive for extended periods without feeding. Data on the biotic and abiotic conditions influencing their field presence/absence, distribution, and abundance are, however, limited. Methods and Findings Warthog burrows and sandy crevices at the base of granite boulders were sampled for Ornithodoros soft ticks in Coutada 9-Macossa Game Reserve , Central Mozambique. Of the 140 sites investigated, 100 sites were infested, and 4,195 soft ticks were collected from these sites. Environmental variables (habitat, soil, altitude, humidity, vegetation, Normalised Difference Vegetation Index (NDVI) and land cover) were recorded at sites or retrieved from public databases. We found that habitat type and soil texture significantly affect soft tick collection rate in Coutada 9. Mitochondrial 16S rRNA gene sequencing of a subset of samples (n=83) identified the ticks as Ornithodoros phacochoerus . In addition, cytochrome b gene blood meal analysis of 136 engorged ticks successfully retrieved 5.88% (8/136) sequences of sufficient quality and identified three distinct vertebrate host donors, viz. Phacochoerus africanus (n=4), Kinixys zombensis (n=2) and Canis lupus familiaris (n=1). Conclusions Environmental factors affecting Ornithodoros phacochoerus tick collection rate include habitat type and soil texture. The warthog was the most frequently detected host among the small number of successful blood meal identifications. In addition, our results confirm that O . phacochoerus ticks also feed on alternative available hosts.