CHRONIC ULCERS IN LOWER EXTREMITIES OF HUMAN BEINGS CAUSED BY STINGS OF FRESHWATER STINGRAYS (Potamotrygonidae) IN BRAZILIAN RIVERS: EPIDEMIOLOGIC, CLINIC AND THERAPEUTICAL ASPECTS

Haddad Jr, V. (1,2) Cardoso, J.L.C.(2), Ribeiro, L.M.G.(3), Talhari, S.(4), Magalhães, M.R.(5), Paula Neto, J.B.(6)

(1)Universidade Estadual Paulista, (2)Instituto Butantan, (3)Três Lagoas, Mato Grosso do Sul, (4)Fundação Universidade do Amazonas, (5)Universidade Católica de Goiás, (6)ITPAC, Hospital de Doenças Tropicais, Tocantins.

OBJECTIVE: The authors report twenty-eight accidents caused by freshwater stingrays (family Potamotrygonidae) emphasizing the clinical aspects, in special the cutaneous necrosis that evolved to chronic ulcers in lower limbs.

METHODS AND PATIENTS: The authors observed patients in rivers of North, Midwest and Southwest regions of Brazil (Araguaia, Amazon, Paraguai and Parana rivers) and clinical and epidemiological aspects of the accidents were registered.

RESULTS: The stingray was always stepped by the victim while wading in shallow waters. The mechanism of the envenomation by the caudal spine is the same for marine stingrays. The freshwater stingrays occur in South America rivers, swamps and lakes, especially in Amazonas, Paraná and Paraguai rivers. The venom is localized in spine(s) on the caudal appendix and can to provoke intense pain, sudoresis, vomiting, diarrhea and cardiac arrythmias. The report of deaths are dubious, but the secondary infection can be very important and occasionally may provoke the death.

CONCLUSION: The necrosis appears in 12-24 hours and the ulcers in one a two weeks from the time of accident. The initial treatment for the stings was the immersion of the point injured in hot water during 30-90 minutes, since the venom of the fishes can be neutralized at high temperatures. The treatment of the ulcers is made by intensive washing, antibiotics and occasionally cutaneous grafts on the affected point, with good results.

Reference

Haddad JR, V. Atlas de animais aquáticos perigosos do Brasil. Editora Roca, São Paulo, 2000.

CORRESPONDENCE TO:

HADDAD JR., V., Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, Brasil, Caixa Postal 557, CEP 18618-000, Botucatu, SP, Brasil, Email: haddadjr@fmb.unesp.br