Molecular detection of Coxiella spp. in ticks (Ixodidae and Argasidae) infesting domestic and wild animals: with notes on the epidemiology of tick-borne Coxiella burnetii in Asia

Abstract

Tick-borneCoxiellaspp. are emerging in novel regions infecting different hosts, but information regarding their occurrence is limited. The purpose of this study was the molecular screening ofCoxiellaspp. in various ticks infesting goats, sheep, camels, cattle, wild mice, and domestic fowls (Gallus gallus domesticus) in various districts of Khyber Pakhtunkhwa, Pakistan. Morphologically identified tick species were confirmed by obtaining theircox1sequences and were molecularly screened forCoxiellaspp. by sequencingGroELfragments. Almost 345 out of 678 (50.9%) hosts were infested by nine tick species. Regarding the age groups, the hosts having an age >3 years were highly infested (192/345, 55.6%), while gender-wise infestation was higher in female hosts (237/345, 68.7%). In collected ticks, the nymphs were outnumbered (613/1,119, 54.8%), followed by adult females (293/1,119, 26.2%) and males (213/1,119, 19.7%). A total of 227 ticks were processed for molecular identification and detection ofCoxiellaspp. The obtainedcox1sequences of nine tick species such asHyalomma dromedarii, Hyalomma anatolicum, Haemaphysalis cornupunctata, Haemaphysalis bispinosa, Haemaphysalis danieli, Haemaphysalis montgomeryi, Rhipicephalus haemaphysaloides, Rhipicephalus microplus, andArgas persicusshowed maximum identities between 99.6% and 100% with the same species and in the phylogenetic tree, clustered to the corresponding species. All the tick species exceptHa. danieliandR. micropluswere found positive forCoxiellaspp. (40/227, 17.6%), includingCoxiella burnetii(15/40, 6.7%),Coxiellaendosymbionts (14/40, 6.3%), and differentCoxiellaspp. (11/40, 4.9%). By the BLAST results, theGroELfragments ofCoxiellaspp. showed maximum identity toC. burnetii, Coxiellaendosymbionts, andCoxiellasp., and phylogenetically clustered to the corresponding species. This is the first comprehensive report regarding the genetic characterization ofCoxiellaspp. in Pakistan's ticks infesting domestic and wild hosts. Proper surveillance and management measures should be undertaken to avoid health risks.