Tick-Borne Infections in Turkey

Tick-borne infections represent a significant public health concern in Turkey, with diverse pathogens transmitted by various tick vectors across different geographic regions and ecological zones. Crimean-Congo hemorrhagic fever (CCHF) is endemic in central and eastern Anatolia (Tokat, Sivas, Yozgat, Kelkit valley among highest endemic areas), caused by Nairovirus from Bunyaviridae family, transmitted primarily by Hyalomma marginatum ticks but also by direct contact with infected animal blood/tissue and human-to-human nosocomial transmission. CCHF is characterized by abrupt fever, hemorrhagic manifestations (petechiae, ecchymoses, mucosal bleeding, gastrointestinal hemorrhage), thrombocytopenia, leukopenia, hepatic dysfunction, mortality 5-30% without treatment, ribavirin and supportive care reduce mortality, vaccine in development.

Lyme borreliosis is increasingly recognized in Turkey, particularly in Black Sea region forests and northern Anatolia, caused by Borrelia burgdorferi sensu lato (multiple genospecies including B. afzelii, B. garinii, B. burgdorferi sensu stricto), transmitted by Ixodes ricinus ticks. Clinical stages: early localized (erythema migrans, days to weeks after bite), early disseminated (multiple erythema migrans, neurologic involvement with cranial neuropathies, meningitis, radiculopathy, cardiac involvement with conduction blocks, weeks to months), late disseminated (chronic arthritis, acrodermatitis chronica atrophicans, neuroborreliosis with encephalopathy, months to years). Diagnosis: clinical with characteristic erythema migrans (>5 cm, expanding), serology with two-tier testing (ELISA followed by Western blot), PCR for selected specimens. Treatment: doxycycline 100 mg twice daily for 14-21 days for early Lyme, ceftriaxone 2 g daily for 14-28 days for neuroborreliosis or late stages, amoxicillin alternative for pregnant patients/children.

Tularemia (Francisella tularensis) is endemic in Turkey, with oropharyngeal form predominant (water-borne transmission from contaminated streams, wells in rural areas of Central Anatolia, Black Sea, Eastern Anatolia regions), but also tick-borne transmission via Dermacentor and Ixodes ticks causing ulceroglandular form. Multiple outbreaks documented with hundreds of cases. Treatment with streptomycin, gentamicin, or oral doxycycline/ciprofloxacin. Mediterranean spotted fever (Rickettsia conorii) endemic in southern coastal regions (Mediterranean, Aegean), transmitted by Rhipicephalus sanguineus (brown dog tick), characterized by fever, eschar at tick bite site (tache noire), rash including palms and soles, treated with doxycycline. Q fever (Coxiella burnetii) endemic in agricultural areas with livestock exposure (sheep, goats, cattle), presents with fever, pneumonia, hepatitis, with chronic form causing endocarditis, treated with doxycycline (acute) or doxycycline plus hydroxychloroquine (chronic). Tick-borne encephalitis (TBE) emerging in Black Sea forested regions. Babesiosis rare, Anaplasma phagocytophilum reported. Prevention: avoid tick-infested areas, protective clothing, DEET or permethrin repellents, prompt tick removal with fine-tipped tweezers (within 24-48 hours reduces transmission), surveillance programs in endemic regions, education of healthcare workers and public, vaccination for at-risk populations (CCHF vaccine being developed, TBE vaccine available).