engleski

Rickettsia raoultii in Dermacentor reticulatus ticks from Croatia

Objective: In Croatia, ft. helvetica and ft. slovaca have been recently de¬tected in D. reticulatus ticks. Also ft. hoogstraalii has been detected in Haemaphysalis sulcata in this country. The aim of this study was to de¬tect rickettsial agents in Croatian ticks and establish laboratory colonies of infected ticks. Methods: Using the cloth-dragging method, during April-May 2007, 159 adult D. reticulatus ticks and 9 Ixodes sp. ticks were collected from meadows in 2 different locations near Cakovec, in the central part of Medjimurje County. Alive ticks were sent to Unite des Rickettsies, Mar¬seille, France. Ticks were stored in environmental incubators at 20°C and 85% RH with a day/night photoperiod of 16:8 (L:D) h. Ten females and ten males were placed on a New Zealand White rabbit [Oryctola-gus cuniculus), that was used as the host for the blood meal. After they laid eggs, DNA was extracted from each engorged female tick and all other tick samples. DNA samples were tested by quantitative (q)PCR for rickettsial gltk. DNA of positive samples was tested by standard PCR as¬says incorporating the primers of ompA gene. Larvae and subsequently nymphs of one infected and non-infected tick were placed on rab¬bits. The next generation of infected female ticks (larvae, nymphs and adults) were tested by PCR and sequencing. Results: A total of 39 of 89 D. reticulatus ticks (44%) were positive by qPCR for gltA gene, presented in all Rickettsiae. ft. raoultii was identified on the basis of a 99.84% similarity (630/631) in ompA nucleotide se¬quence (HM161789). Four successive generations were obtained from aD. reticulatus infected female. Non-infected tick colonies were also maintained. Conclusions: Our data showed the presence of ft. raoultii for the first time in 0. reticulatus collected in Croatia. This infectious agent was de¬tected in several European countries: France, Russia, Poland, Slovakia, Spain, Portugal, Germany, UK, Italy and the Netherlands. R. raoultii has been found in D. marginatus, D. reticulatus, D. silvarum, and D. nuttalii. This agent causes a SENLAT syndrome: scalp eschar and nech lymph-adenopathy after tick bite. The Croatian physicians need to be aware of presence of this disease in this area.

Rickettsia raoultii; Dermacentor reticulatus; ticks; Croatia

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