Characterization of anti-crotalic antibodies

AbstractCrotalus durissus terrificus, C. d. collilineatus, C. d. cascavella and C. d. marajoensis are responsible minor but severe snake bites in Brazil. The venoms of these snakes share the presence of crotoxin, a neurotoxin comprising of two associated components, crotapotin and phospholipase A2 (PLA2). Treatment of the victims with specific antiserum is the unique effective therapeutic measure. The ability of anti-Crotalus antisera produced by the routine using crude venom to immunize horses or purified crotoxin and PLA2 as individual immunogens was compared. Antisera obtained from horses immunized with C. durissus terrificus crude venom were able to recognize and neutralize not only the toxins presents in C. durissus terrificus, but also the ones present in the venoms from C. d. collilineatus, C. d. cascavella and C. d. marajoensis. Antisera from horses immunized with individual crotoxin or PLA2, although in lesser titers, were also able of recognizing the toxins in all four Crotalus species and neutralize the lethality of the C. d. terrificus venom

Clinical and epidemiological features of definitive and presumed loxoscelism in São Paulo, Brazil Aspectos clínicos e epidemiológicos do loxoscelismo em São Paulo, Brasil

A retrospective study analysed 359 proven or presume cases of loxoscelism seen at the Hospital Vital Brazil, Instituto Butantan, São Paulo, Brazil, between 1985 and 1996. The spider was identified in 14%. The bites occurred predominantly in the urban areas (73%) between September and February. Patients > 14 years were commonest inflicted (92%) and 41% were bitten while getting dressed. Only 11% sought medical care within the first 12 hours post bite. Cutaneous loxoscelism was the commonest form presenting (96%); commonest manifestations were: pain (76%), erythema (72%), edema with enduration (66%), ecchymosis (39%). Skin necrosis occurred in 53% of patients, most frequently seen on trunk, tigh and upper arm, and when patients seek medical care more than 72 hours after bite. Local infection was detected in 12 patients (3%). Hemolysis was confirmed in 4 cases (1.1%). Generalised cutaneous rash, fever and headache were also observed in 48% of the total of patients. None of them had acute renal failure or died. Treatment usually involved antivenom administration (66%), being associated with corticosteroids (47%) or dapsone (30%). Presumptive diagnosis of loxoscelism may be established based on clinical and epidemiological findings. Further investigations are required to prove the value of antivenom and other treatment schedules.<br>Foram analisados, em um estudo retrospectivo, 359 casos de loxoscelismo comprovados ou presumidos, acompanhados no Hospital Vital Brazil, Instituto Butantan, São Paulo, Brasil, entre 1985 e 1996. A aranha foi identificada em 14% dos casos. Os acidentes predominaram nas áreas urbanas (73%), entre setembro e fevereiro. Pacientes maiores de 14 anos foram mais freqüentemente atingidos (92%) e 41% foram picados ao se vestir. Apenas 11% procuraram o serviço médico nas primeiras horas após a picada. A forma cutânea foi a mais freqüente (96%), sendo as principais manifestações descritas: dor (76%), eritema (72%), edema com enduração (66%), equimose (39%). Necrose cutânea ocorreu em 53% dos pacientes, sendo mais freqüentemente observada no tronco, coxa e braço, e naqueles que procuraram atendimento médico mais de 72 horas após o acidente. Infecção local foi detectada em 12 pacientes (3%). A hemólise foi confirmada em 4 casos (1,1%). Exantema generalizado, febre e cefaléia foram observados em 48% dos pacientes. Não se verificou insuficiência renal ou óbito. O antiveneno foi administrado em 66% dos casos, associado a corticosteróide em 47% ou a dapsona em 30%. O diagnóstico presuntivo de loxoscelismo pode ser estabelecido baseado em achados clínicos e epidemiológicos. Maiores investigações são necessárias para se comprovar o valor do antiveneno e outras drogas