Copra itch outbreak caused by Tyrophagus longior mite in a family at village number 3, Thaimueang Subdistrict, Thaimueang District, Phang Nga Province, Thailand, 25 June–4 July 2016

Abstract

Background: On 5 July 2016, Phang-Nga Provincial Health Office received a notification of skin lesions and severe itching in a family. An outbreak investigation was undergone with the aim to confirm diagnosis and outbreak, identify the source of outbreak and implement control measures.
Methods: Cases were interviewed about clinical presentation, including exposure history, and physical examination was performed for all the suspected cases. Skin lesions were carefully explored and identify a parasite by direct microscopy. Complete blood count was done in all cases. Active case finding of people with any skin lesion and itching was carried out in the village. Environmental survey was done at the cases’ residents as well.
Results: Total six cases were identified, with age between 11 and 32 years old. All cases were living in the same family and onset dates of illness were during June 22-July 3, 2016. There was no additional case in the village. The most common skin lesion was erythematous papule and severe itching. Body (83%) and neck (67%) were the most affected areas. Leukocytosis was found in two cases. One mite was removed from one case and subsequently identified as Tyrophagus longior mite. Hence, copra itch could be cause of this outbreak. Six months ago, this house was used to be a cottage industry of handling copra and the dried kernel of the coconuts. Three months later, this family moved to this house. Three unused copra beds were also found in the bedrooms.
Conclusions and discussions: Copra itch is one of the most likely causes of the skin disease outbreaks. A previous outbreak was reported in the Netherlands since 1953. The clinical presentation was also matched with this disease. The copra beds were suspected to be source of the outbreak, which were removed and destroyed by burning. Gamma Benzene Hexachlorine (0.1%) was provided for the skin lesions and doxycycline was prescribed to prevent secondary skin infection. In addition, deltamethrin spaying was carried out to control the vector.