Molecular identification of tick-borne pathogens in asymptomatic individuals with human immunodeficiency virus type 1 (HIV-1) infection: a retrospective study

Background: The studies on the occurrence and diversity of tick-borne infections in HIV-infected individuals have been few, and the subject has been relatively neglected when compared with other common infections associated with HIV. In HIV-positive patients in whom a serological diagnostics is complicated due to reduced positive predictive value, a method where the microorganism is detected directly is of great value. Therefore, we performed a molecular study to ascertain the prevalence and incidence of tick-borne infections in HIV-infected persons in Poland, an endemic area for Ixodes ricinus ticks. Methods: Genomic DNA was isolated from whole blood of tested patients. Detection of tick-borne pathogens was performed by amplification and sequencing of different loci. Molecular and phylogenetic analyses of obtained nucleotide sequences were performed. Serum samples were analyzed for antibodies against tick-borne pathogens by using commercial tests in all patients. Results: Among 148 studied blood samples from HIV-infected patients, two cases (1.4%) of infection with tickborne pathogen were reported. No symptoms of tick-borne infection were observed in these cases. In one case a patient was infected with Anaplasma phagocytophilum -the agent of human granulocytic anaplasmosis (HGA) and in the other with Borrelia garinii. Conclusions: Our study revealed the first case of HIV positive patient infected with A. phagocytophilum. Asymptomatic tick-borne infection can occur in HIV-positive patients. The detailed history of tick bites, especially in endemic tick areas, should be considered as part of anamnesis in routine clinical care of HIV-positive patients.