Hard ticks (Ixodida: Ixodidae) on humans in Nicaragua.

Ticks pose an increasing threat to public health due to their geographic expansion and the emergence of tick-borne pathogens. In Nicaragua, information on ticks that infest humans is limited. This study reports human tick bites recorded between March 2023 and September 2025 in rural and peri‑urban areas of the departments of Chontales and Río San Juan. Twenty-five cases were analyzed, with 172 ticks collected (28 females, 6 males, 13 nymphs, and 125 larvae). Morphological identification revealed five species: Amblyomma mixtum, Amblyomma ovale, Amblyomma cf. parvum, Rhipicephalus linnaei, and Rhipicephalus microplus. Amblyomma mixtum was the dominant species, present in 80% of cases, and all developmental stages were found attached to humans. Skin reactions ranged from pruritus and local erythema to intense inflammatory responses associated with massive larval infestations (up to 123 larvae in a single individual). One infested individual presented transient systemic symptoms (fatigue, generalized pruritus, difficulty concentrating, and insomnia) that resolved after tick removal. This is the first report of A. ovale, A. cf. parvum, R. linnaei, and R. microplus infesting humans in Nicaragua. These findings underscore the risk of tick-borne diseases in rural areas of Nicaragua and the need for active surveillance, accurate tick identification, and molecular studies to detect rickettsial agents and other potential pathogens. Information on preferred attachment sites (e.g., lower limbs) is clinically relevant and may help inform preventive measures.