Prevalence and molecular characterization of ticks and tick-borne pathogens of one-humped camels (Camelus dromedarius) in Nigeria

Background: Ticks are hematophagous arthropods responsible for maintenance and transmission of several pathogens of veterinary and medical importance. Current knowledge on species diversity and pathogens transmitted by ticks infesting camels in Nigeria is limited. Therefore, the aim of this study was to unravel the status of ticks and tick-borne pathogens of camels in Nigeria. Methods: Blood samples (n = 176) and adult ticks (n = 593) were collected from one-humped camels (Camelus dromedarius) of both sexes in three locations (Kano, Jigawa and Sokoto states) in north-western Nigeria and screened for the presence ofRickettsiaspp.,Babesiaspp.,Anaplasma marginale,Anaplasmaspp. andCoxiella-like organisms using molecular techniques. All ticks were identified to species level using a combination of morphological and molecular methods. Results: Ticks comprised the three generaHyalomma,AmblyommaandRhipicephalus.Hyalomma dromedariiwas the most frequently detected tick species (n = 465; 78.4%) whileAmblyomma variegatum(n = 1; 0.2%) andRhipicephalus evertsi evertsi(n = 1; 0.2%) were less frequent. Other tick species includedH. truncatum(n = 87; 14.7%),H. rufipes(n = 19; 3.2%),H. impeltatum(n = 18; 3.0%) andH. impressum(n = 2; 0.3%). The minimum infection rates of tick-borne pathogens in 231 tick pools includedRickettsia aeschlimannii(n = 51; 8.6%);Babesiaspecies, (n = 4; 0.7%) comprising ofB. occultans(n = 2),B. caballi(n = 1) andBabesiasp. (n = 1);Coxiella burnetii(n = 17; 2.9%); and endosymbionts in ticks (n = 62; 10.5%). We detected DNA of CandidatusAnaplasma camelli in 40.3% of the blood samples of camels. Other tick-borne pathogens includingAnaplasma marginalewere not detected. Analysis of risk factors associated with both tick infestation and infection withAnaplasmaspp. in the blood indicated that age and body condition scores of the camels were significant (P < 0.05) risk factors while gender was not. Conclusions: This study reports low to moderate prevalence rates of selected tick-borne pathogens associated with camels and their ticks in north-western Nigeria. The presence of zoonoticR. aeschlimanniiemphasizes the need for a concerted tick control programme in Nigeria.