Molecular detection of Rickettsia africae in Amblyomma ticks collected in cattle from Southern and Central Mozambique

INTRODUCTION : Rickettsia are Gram-negative and obligate intracellular bacteria, which cause typhus and spotted fever-like diseases in humans. In Africa, Rickettsia africae of the Spotted Fever Group Rickettsia (SFGR) is the etiologic agent of the African Tick-Bite Fever. The disease is transmitted by ticks of the genus Amblyomma, which serve as vectors and reservoirs of Rickettsia. In this study, we aimed to detect Rickettsia species in ticks collected from cattle in south and central Mozambique. METHODOLOGY : DNA from 412 adult ticks and 22 pools of larvae were extracted and tested for the presence of Rickettsia genes gltA, ompA and ompB by PCR, followed by sequencing and phylogenetic analysis. RESULTS : Our results showed that in adult ticks, 79.5% (n = 330), 66% (n = 274) and 67% (n = 275) samples were positive for gltA, ompA and ompB genes, respectively. Among the 22 pools of larvae analysed, 77.2% (n = 17) were positive for the three genes tested. The infection rates ranged from 43% to 100% for Rickettsia by gltA in all locations studied, with maximum values of 100% observed in the districts of Maputo province namely Changalane, Boane and Matutuine district. The phylogenetic analysis of amplified sequences revealed that samples under study grouped with R. africae for the 3 genes. CONCLUSION : The study showed that Spotted Fever Group Rickettsia represented by R. africae widely circulate in Amblyomma ticks collected in south and central regions of Mozambique.This manuscript is a part of the Master thesis of VM for the Master School in Biotechnology at the Eduardo Mondlane University.This manuscript is a part of the Master thesis of VM for the Master School in Biotechnology at the Eduardo Mondlane University. VM and ET were supported by the Italian Agency for Cooperation and Development (AICS) projects AID10524 and AID11096. The study was also implemented under the framework of the GeosAf project (www.rp-pcp.org/projects/) of the African, Caribbean and Pacific (ACP) Group of States, and the authors acknowledge Dr Fernando Chanisso and Eng. Valter Nuaila for their support in the experimental work (Center for Biotechnology, Eduardo Mondlane University).The Italian Agency for Cooperation and Development (AICS)http://www.jidc.org/index.php/journalam2021Veterinary Tropical Disease