Spotted Fever Group Rickettsia spp. Diversity in Ticks and the First Report of Rickettsia hoogstraalii in Romania

Abstract

Tickborne bacterial pathogens have been described worldwide as risk factors for both animal and human health. Spotted fevers caused by Rickettsiae may cause non-specific symptoms, which make clinical diagnosis difficult. The aim of the current study was to evaluate and review the diversity of SFG Rickettsiae in ticks collected in 41 counties in Romania. A total of 2028 questing and engorged ticks collected in Romania belonging to five species were tested by PCR amplification of <i>Rickettsia</i> spp. gltA and 17-D gene fragments: <i>Ixodes ricinus</i> (<i>n</i> = 1128), <i>Dermacentor marginatus</i> (<i>n</i> = 507), <i>D. reticulatus</i> (<i>n</i> = 165), <i>Rhipicephalus rossicus</i> (<i>n</i> = 128) and <i>Haemaphysalis punctata</i> (<i>n</i> = 100). Five <i>Rickettsia</i> species were identified following DNA sequence analysis: <i>R. helvetica</i>, <i>R. monacensis</i>, <i>R. slovaca</i>, <i>R. raoultii</i>, and <i>R. hoogstraalii.</i> The most common species detected was <i>R. monacensis</i>. Moreover, <i>R. hoogstraalii</i> was detected for the first time in Romania and in <i>R. rossicus</i> ticks. The detection of <i>R. raoultii</i> and <i>R. monacensis</i> in questing larvae of <i>Hae. punctata</i> suggests the possible transovarial transmission of these <i>Rickettsia</i> species in ticks. The detection of <i>R. hoogstraalii</i> for the first time in Romania increases the reported SFG <i>Rickettsia</i> diversity in the country.