Outbreak of human infestation by Ornithonyssus sylviarum associated with migratory Sturnus roseus in Bukan, Iran,...

Migratory birds act as important dispersal hosts for parasitic mites, facilitating their spread over long geographic distances and potentially contributing to the emergence of infestations in previously unaffected areas. This study investigates an unprecedented outbreak of mite infestation among residents of two villages in northwestern Iran, in July 2025. This outbreak coincided with the arrival and nesting of migratory rosy starlings (Sturnus roseus) within or near human dwellings. A comprehensive survey and clinical examination of the affected villagers revealed that 37.6% of residents in Ebrahim Khesar and 26.3% of residents in ZavehKuh presented with skin lesions consistent with mite parasitism, with housewives representing the most affected occupational group. All itching and skin irritation occurs during the day and mainly involved the trunk and hands. The mean age of affected individuals did not differ significantly between the two villages (35.7 ± 23.1 vs. 41.0 ± 25.8 years; t = -1.111, df = 100, P = 0.269; 95% CI: -15.0-4.2). Mites were collected from live birds and their carcasses and identified as Ornithonyssus sylviarum using morphological criteria. The close association between nesting rosy starlings and human settlements facilitated direct transmission of mites to humans, resulting in widespread symptoms of pruritus and dermatitis, but no systemic disease. This study found rosy starlings introduced bird mites (O. sylviarum) to homes, causing human infestations. Successful control depends on identifying the mite species, bird/nest management, education, and surveillance. A better understanding of the factors driving these outbreaks is essential for informing prevention strategies and reducing the impact of mite infestations on vulnerable populations.