Rickettsia africae an Agent of African Tick Bite Fever in Ticks Collected from Domestic Animals in Eastern Cape, South Africa

Background:Ticks transmit a plethora of pathogens of zoonotic implications. Their distribution, diversity and the pathogens they transmit differ from one ecological location to another.Rickettsia africaeis the agent of African tick bite fever found in South Africa, a zoonotic infection that is frequently reported among travelers who have visited many sub-Saharan African countries where the pathogen is prevalent.Methods:Ticks were collected from domestic animals in Raymond Nkandla Municipality, Eastern Cape, South Africa. The ticks were identified morphologically prior to DNA extraction followed by molecular identification of randomly selected ticks from the morphologically delineated groups. To assess for the presence of tick-borne pathogens belonging toRickettsiaspp. by PCR (polymerase chain reaction), we used specific primer pairs targeting thegltA,ompA andompB genes. The selected amplified ticks, all positiveompB and forty threeompA amplicons were sequenced in a commercial sequencing facility. The obtained nucleotide sequences were edited and subjected to BLASTn for homology search and phylogenetic analyses were performed with MEGA 7 Version for genetic relationships with curated reference sequences in GenBank.Results:A total of 953 ticks collected in the study were delineated into three genera consisting ofAmblyomma,RhipicephalusandHyalommain decreasing order of abundance. The presence of rickettsial DNA was detected in 60/953 (6.3%) from the three genera of ticks screened. Genetic analyses of the DNA sequences obtained showed that they have phylogenetic relationship to members of the spotted fever group rickettsiae withR. africae, being the predominant SFGR (spotted fever group rickettsiae) detected in the screened ticks.Conclusion:This report shows thatR. africaeis the predominant spotted fever group rickettsiae in ticks collected from domestic animals in the study area and the human health impacts are not known.