First detection of Rickettsia japonica in Hyalomma dromedarii ticks infesting camels from Egypt: A call for enhanced surveillance of tick-borne pathogens.

Abstract

Tick-borne rickettsiosis has posed a significant threat to Egypt, with various pathogenic Rickettsia species being reported. In this study, 134 ticks were collected from camels in Esna City, Luxor, Egypt and all were identified as Hyalomma dromedarii through both morphological and molecular techniques. Using specific primers targeting the citrate synthase (gltA), outer membrane protein A (ompA) and 17 kD antigen (17 kDa) genes, Rickettsia japonica was detected via conventional and nested PCR assays. Remarkably, two samples tested positive for R. japonica across all three genes, indicating a prevalence of 1.5%. Phylogenetic analysis based on the gltA, ompA and 17 kDa genes confirmed the presence of R. japonica within H. dromedarii ticks. This is the first reported detection of R. japonica in Egypt. These findings highlight the urgent need to investigate the origin and spread of R. japonica in the country and underscore the importance of continuous surveillance and data collection on lesser-known pathogens circulating in ticks as part of Egypt's public health efforts to manage tick-borne diseases.