Detection of Tick-Borne Rickettsia Species in Ticks Collected from Cattle in Some Selected Sites in Ghana
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Date
2019-07
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Publisher
University of Ghana
Abstract
Ticks continue to facilitate the spread of pathogens globally, thereby influencing the health of both humans and animals. Ticks have been documented to infest animals including pets and livestock, transmitting bacterial pathogens including Rickettsia species. It is common to find many Ghanaian households rearing animals, thus increasing the risk of infection. It is therefore important to identify the present tick species and determine their potential to transmit diseases. This study sought to collect, identify and analyse ticks from livestock for Rickettsia species across some selected sites in Guinea Savana and Coastal grassland of Ghana. The ticks were identified using available keys and pooled by sex and species. A total of 1,493 ticks were collected comprising of 516 (34.56%) females and 977 (65.44%) males. Seven tick species were identified with Amblyomma variegatum (73.14%) as the predominant species and Rhipicephalus boophilus (0.07%) as the least occurring species. There was a significant difference (p<0.001) between the tick species identified from the northern (Guinea Savanna) and southern (Coastal grassland) sectors. Out of the 541 pools, Rickettsia species was detected in 308 (56.93%) pools with Amblyomma variegatum (n=252 (69.61%)) being the most infected species. From the Rickettsia species positive pools, 238 (77.27%) were found to be positive for Rickettsia africae with A. variegatum (80.16%) recording the highest positivity. Using the PoolScreen software, Hyalomma truncatum was found to have the highest infection rate of 76.0% (95% CI, 30.0-99.0). However, the highest Rickettsia africae infection rate of 54.2% (95% CI, 47.8-60.7) was recorded in pools of A. variegatum. Further sequencing of Rickettsia positive pools revealed the presence of R. africae and R. aeschlimannii. This study reports the first molecular detection of R. africae and Rickettsia aeschlimannii in tick species in Ghana. There is the need to employ control measures to prevent infections from occurring in human populations within the two study areas.
Description
MPhil. Zoology
Keywords
Rickettsiae, Ghana, Arthropods