Based on the fact that ticks are known vectors of numerous pathogens, e.g. However, considering the sporadic nature of the cases of facial palsy despite high incidence of otoacariasis, we thought about other possible aetio-pathological conditions by about 2011. Thus patients were managed as if other cases of facial palsy, but recovery was slow and some patients took years. As it was an established fact that some tick species are capable of producing paralytic toxins, we attributed tick toxicosis and paralysis to explain the emerging problem of 7th cranial nerve palsy. However, by 1999, a very occasional detection of unilateral facial palsy associated with intra-aural tick bite at the ENT clinic, Kandy aroused curiosity and prompted us to investigate such cases from 2001. Even though, intra-aural tick infestation is an increasing problem, virtually all patients make recovery without local or systemic clinical problems. Another paper from Ratnapura district of Sri Lanka described 870 patients of intra-aural tick infestation over 2 years from year 2000 where most of the offending ticks belonged to genera of Rhipicephalus, Amblyomma and Hyalomma (Fig. From the same clinic another publication describes 66 patients with otoacariasis in 2014. At the dawn of the century, first report of intra-aural tick infestations was published in 2003 from the ENT clinic, General hospital, Kandy, Sri Lanka where investigators described 29 patients and recovery of nymphs of 29 Dermacentor auratus and one Hyalomma marginatus isaaci from ear canals of patients. Reports of tick infestations in humans are few in Sri Lanka, first being a report published in 1965 describing 4 genera of ticks recovered from human skin. Over the last two decades intra-aural tick infestations are becoming a common problem seen at the ear-nose-throat (ENT) clinics in the central hills of Sri Lanka, however, the exact incidence remains unknown. The tick infestation of ear canal is called otoacariasis. Ticks belong to genera of Dermacentor, Amblyomma, Hyalomma, Boophilus and Rhipicephalus are common vectors of both animal and human diseases in Sri Lanka Ticks have three stages of development namely larva, nymph and adult each of which is capable of transmission of diseases. Sri Lanka, a tropical island in the Indian ocean has a rich biodiversity including its ubiquitous tick population which comprises about 31 species of ticks belonging to 11 genera. On contrary to popular toxin theory, we were able to demonstrate treatable rickettsial aetio-pathology as the cause of otoacariasis associated lower motor facial palsy in Sri Lanka. Identified ticks belonged to Dermacentor, Amblyomma, Rhipicephalus and Hyalomma species. They had strong sero-conversion of immunofluorescence antibodies against spotted fever rickettsioses and the tick harvested from the last patient was PCR positive for rickettsial DNA. Last 5 patients were treated with doxycycline and recovered in 4 weeks. First 12 patients without specific treatment took 1–55 months for recovery and 4 had axonal degeneration. There were 29 patients with mean age of 46 years (range 22–76 years) with male to female ratio of 1:1.9. The facial palsies were assessed with nerve conduction studies and, harvested ticks were identified. MethodsĪll cases having isolated unilateral facial nerve palsy associated with otoacariasis presented to, Ear Nose and Throat clinic at General Hospital Kandy, Sri Lanka from 2001 to 2016 were included in the study. Very occasional detection of isolated unilateral facial nerve palsy associated with otoacariasis attributed to toxin damage of the nerve prompted us to study the clinico-epidemiology and aetio-pathology of the problem. Over the last two decades intra-aural tick infestation (otoacariasis) has been a common occurrence in the hilly central region in Sri Lanka.
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