Genetic characterization of Coxiella burnetii in Amblyomma varigatum ticks from North-central Nigeria: public health importance

Abstract

Aim: The purpose of this pilot study was to genetically identify and characterize Coxiella burnetii from Amblyommavarigatum ticks collected on cattle in North central Nigeria.Materials and Methods: A total of 40 partially fed ticks morphologically identified as adult A. variegatum ticks collectedfrom cattle owned by Fulani pastoralists were evaluated for the presence of C. burnetii using PCR, cloning, and sequencing ofthe heat shock polypeptide gene htpB.Results: C. burnetii DNAwas detected in 10 (25%) of the ticks analyzed. Sequences for the C. burnetii gene htpB detected inour samples had 99-100% identity to all other C. burnetii that have been described and that are deposited in the GenBankdatabase. Phylogenetic analysis using neighbor-joining method indicates the clustering of C. burnetii sequences from ourstudy areas with those collected from Oyo state, South-western Nigeria and Spain.Conclusion: This study shows a high infection rate of C. burnetii in A. variegatum ticks in the study areas. Phylogeneticinferences indicates that the strain of C. burnetii found in the North central states of Plateau and Nasarawa were same as thosepreviously reported in the South western state of Oyo. The presence of this pathogen in naturally occurring A. variegatum tickpopulations could present an additional risk of Q-fever disease to humans, especially to the pastoralists that are closelyassociated with their animals and are easily exposed to tick bites. Therefore, further studies are needed to assess thecompetence of A. variegatum ticks as vectors of C. burnetii pathogens.

Keywords

• Amblyomma variegatum
• Coxiella burnetii
• Nigeria
• ticks
• zoonosis