Parasitismo do ácaro Ornithonyssus bursa em humanos no Sul do Brasil
Oliveira, Camila BelmonteTonin, Alexandre AlbertoMonteiro, Silvia Gonzalez
Background: The mite Ornithonyssus bursa is a bloodsucking parasite of domestic and wild birds and it is typical of tropical regions. On the host it can cause considerable loss of blood and lesions with intense itching. Cases of parasitism in human beings have been reported causing dermatitis, and most of these cases are due to the presence of nests of synanthropic birds near of the residences. When in large infestations or lack of hosts, the mites leave the nests to perform the parasitism in humans. Human infestation occurs mainly in people who handle infected birds and nests, or when happen the dispersion of these mites, through some path which lead to the interior of homes, factories and hospitals. Case: The present case occurred in November of 2008, when one of the dwellers of an apartment on the fourth floor of a building downtown in Santa Maria, woke up with pruritic lesions over the arms and legs. Upon inspection of the bedroom, several mites were seen, measuring almost a millimeter long, coming out of a pipe of a portable air conditioner installed on site. They were already scattered by the inside walls, floor and bed. The mites were collected and maintained in 70% alcohol for later identification. After the clarification the slides mounting were performed, and the mites with measure between 0.48 mm wide by 0.74 mm long were classified by the position of the anal opening, formed by the dorsal plate and three pairs of bristle on the sternal plate, as belonging to the species Ornithonyssus bursa. On external outlet of the air portable conditioner, a nest with a couple of birds and three cubs was found. The birds were identified as belonging to the species Myiodynastes maculatus, popularly known as brindle Bem-Te-Vi. The birds were removed from the place and treated with antiparasitic macrolactones to control the infestation. Discussion: In the present case report the O. bursa was found inside of an apartment in the downtown area, parasitizing birds which had their nest sheltered in the outlet air of a portable air conditioner. The presence of synanthropic bird brindle Bem-Te-Vi and the ease of access to the interior of the residence led to a home infestation of this ectoparasite. This fact may be happend due to the nesting of birds in urban buildings, seeking for a favorable environment for their survival, specially near of local that providing heat, like heaters, furnaces and hot water pipes. When the young birds parasitized by hematophagous leave the nests, the mites can cause the parasitism in humans mainly by food shortage. In the present study the occurrence of accidental home infestation and accidental parasitism in humans is related to the presence of many specimens of birds in the same nest, with offering of food and favorable environmental conditions for reproduction of the mites and their dissemination. Mite infestations in humans are characterized by erythematous papulovesicles distributed throughout the body, mainly on the limbs and chest. In this case report the parasitism caused erythematous lesions, especially in the arms with intense itching. The dermatitis produced by mesostigmatas hematophagous mites are not specific impeding the diagnosis, and may be confusing with other ectoparasites. For this reason the present diagnosis was performed by isolation and identification of the mite. Based on the description above it was possible to conclude that the bird Myiodynastes maculatus are parasitized by the mite Ornithonyssus bursa and its synanthropic habits allowed the infestation of mites in this residence.
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