Public Health risk of zoonotic ticks in Abeokuta, Southwest Nigeria

Abstract

Ticks are obligate blood-feeders that require a host to survive and reproduce and has been said to be second to mosquito in pathogen  transmission. Tick-borne diseases are increasingly becoming an important public health issue because of the possibility of acquiring them through tick bite and the presence of ticks in environment poses risk to humans and livestock alike. This study was carried out to determine the presence of ticks in Abeokuta environment and to screen harvested ticks for some zoonotic pathogens. Ticks were gathered from ten different spots in Abeokuta Ogun state using the cloth dragging method. The gathered ticks were morphologically identified to genus level using stereo microscope  and grouped based on their developmental stages. Harvested ticks were screened for 5 pathogens of Public Health importance namely Anaplasma, Babesia, Borrelia, Ehrlichia and Rickettsia by Polymerase Chain Reaction (PCR) using extracted DNA from the ticks. A total of 357 ticks were gathered from the environment, the environments were areas where cattle are being grazed. Using their morphology; 19 (5.3%) of ticks were of the genus Amblyomma, 274 (76.6%) were of the Genus Rhipicephalus (sub genus Boophilus), and 64 (17.9%) were of the Genus Rhipicephalus. Using the  developmental stages; 44 (12.3%) of the ticks were adults, 304 (85.2%) were larvae and 9(2.5%) were nymphs. Pathogen prevalence in the harvested ticks was 20.73%. PCR analysis revealed that 2 (0.56%) of ticks were positive for Coxiella and Rickettsia, 28 (7.84%) for Anaplasma, 29 (8.12%) for  Coxiella, 7 (1.96%) ticks were positive for Coxiella and Anaplasma and 8 (2.25%) ticks were positive for Rickettsia. None of the ticks had Babesia and Borrelia. With the presence of Anaplasma, Coxiella and Rickettsia in the harvested ticks, the risk of acquiring infection from bite of ticks by humans  and livestock is very high in the study areas and the possibility of transfer into other areas through movement of goods and services involved in global trade portend danger. Importance of co-infection in the harvested ticks and the dangers they pose in disease transmission to animal and humans are of great public health concern which require Public awareness and education.

Key words: zoonoses, Borrelia, pathogens, Rickettsia