Tick Borne Lymphoadenopathy (TIBOLA) is an emerging zoonosis in Europe, caused by Rickettsia slovaca transmitted by Dermacentor marginatus. Since transovarial transmission of R. slovaca occurs between adult and larval ticks, it is not clear whether wild animals solely serve as the blood source for D. marginatus, or may amplify and transmit the agent to susceptible ticks. R. slovaca was previously identified in ticks and tissues collected from wild boars in Tuscany (Italy), where human cases of TIBOLA were reported. The role of small rodents in R.slovaca transmission was investigated in the same area in 2009-2010. Animals were live trapped, ear biopsies and all the attached ticks were collected and identified. The tick engorgement index (TEI) was calculated. A sample of D. marginatus and mice ear biopsies was selected to detect SFG Rickettsiae by PCR. We performed 22 trapping nights. A total of 145 Apodemus spp. and 34 Myodes glareolus were trapped. The prevalence of R. slovaca was 38.17%(n=50) in D. marginatus collected from mice, and 26.09%(n=6) in host-seeking larval ticks collected in the same area. The TEI of infected ticks was higher than non infected ones, although the difference was not statistically significant. Two out of the 45 ear biopsies were positive. R. raoultii, the agent of a less severe TIBOLA disease, was also detected in two ticks from mice. The high prevalence of R. slovaca in host-seeking tick larvae indicates the maintenance of the pathogen by transovarial transmission in the area. However, the finding for the first time of positive mouse tissues, the high infection prevalence in attached ticks, and the tendency of the infected ones to have a higher TEI, may suggest a role of mice as maintenance or amplifier hosts for R. slovaca.
Role of wild animals in the eco-epidemiology of Rickettsia slovaca
MARTELLO, ELISA;MANNELLI, Alessandro;TOMASSONE, Laura
2012-01-01
Abstract
Tick Borne Lymphoadenopathy (TIBOLA) is an emerging zoonosis in Europe, caused by Rickettsia slovaca transmitted by Dermacentor marginatus. Since transovarial transmission of R. slovaca occurs between adult and larval ticks, it is not clear whether wild animals solely serve as the blood source for D. marginatus, or may amplify and transmit the agent to susceptible ticks. R. slovaca was previously identified in ticks and tissues collected from wild boars in Tuscany (Italy), where human cases of TIBOLA were reported. The role of small rodents in R.slovaca transmission was investigated in the same area in 2009-2010. Animals were live trapped, ear biopsies and all the attached ticks were collected and identified. The tick engorgement index (TEI) was calculated. A sample of D. marginatus and mice ear biopsies was selected to detect SFG Rickettsiae by PCR. We performed 22 trapping nights. A total of 145 Apodemus spp. and 34 Myodes glareolus were trapped. The prevalence of R. slovaca was 38.17%(n=50) in D. marginatus collected from mice, and 26.09%(n=6) in host-seeking larval ticks collected in the same area. The TEI of infected ticks was higher than non infected ones, although the difference was not statistically significant. Two out of the 45 ear biopsies were positive. R. raoultii, the agent of a less severe TIBOLA disease, was also detected in two ticks from mice. The high prevalence of R. slovaca in host-seeking tick larvae indicates the maintenance of the pathogen by transovarial transmission in the area. However, the finding for the first time of positive mouse tissues, the high infection prevalence in attached ticks, and the tendency of the infected ones to have a higher TEI, may suggest a role of mice as maintenance or amplifier hosts for R. slovaca.
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