Prevalence of Spotted Fever Group Rickettsia and Candidatus Lariskella in Multiple Tick Species from Guizhou Province, China

Abstract

Rickettsiales (<i>Rickettsia</i> spp., <i>Ehrlichia</i> spp., and <i>Anaplasma</i> spp., etc.) are generally recognized as potentially emerging tick-borne pathogens. However, some bacteria and areas in China remain uninvestigated. In this study, we collected 113 ticks from mammals in Guizhou Province, Southwest China, and screened for the Rickettsiales bacteria. Subsequently, two spotted fever group <i>Rickettsia</i> species and one <i>Candidatus</i> Lariskella sp. were detected and characterized. "<i>Candidatus</i> Rickettsia jingxinensis" was detected in <i>Rhipicephalus microplus</i> (1/1), <i>Haemaphysalis flava</i> (1/3, 33.33%), <i>Haemaphysalis kitaokai</i> (1/3), and <i>Ixodes sinensis</i> (4/101, 3.96%), whereas <i>Rickettsia monacensis</i> was positive in <i>H. flava</i> (1/3), <i>H. kitaokai</i> (2/3), and <i>I. sinensis</i> ticks (74/101, 73.27%). At least two variants/sub-genotypes were identified in the <i>R. monacensis</i> isolates, and the strikingly high prevalence of <i>R. monacensis</i> may suggest a risk of human infection. Unexpectedly, a <i>Candidatus</i> Lariskella sp. belonging to the family <i>Candidatus</i> Midichloriaceae was detected from <i>Ixodes ovatus</i> (1/4) and <i>I. sinensis</i> (10/101, 9.90%). The <i>gltA</i> and <i>groEL</i> gene sequences were successfully obtained, and they show the highest (74.63-74.89% and 73.31%) similarities to "<i>Candidatus</i> Midichloria mitochondrii", respectively. Herein, we name the species "<i>Candidatus</i> Lariskella guizhouensis". These may be the first recovered <i>gltA</i> and <i>groEL</i> sequences of the genus <i>Candidatus</i> Lariskella.