RESUMEN
"Black widow" spiders belong to the genus Latrodectus and are one of the few spiders in the world whose bite can cause severe envenomation in humans and domestic animals. In Argentina, these spiders are distributed throughout the country and are responsible for the highest number of bites by spiders of toxicological sanitary interest. Here, we studied the toxicity and some biochemical and immunochemical characteristics of eighteen venom samples from Latrodectus spiders from eight different provinces of Argentina, and the neutralization of some of these samples by two therapeutic antivenoms used in the country for the treatment of envenomation and by a anti-Latrodectus antivenom prepared against the venom of Latrodectus mactans from Mexico. We observed important toxicity in all the samples studied and a variation in the toxicity of samples, even in those from the same region and province and even in the same Latrodectus species from the same region. The therapeutic antivenoms efficiently neutralized all the venoms studied.
Asunto(s)
Antivenenos/uso terapéutico , Venenos de Araña/toxicidad , Animales , Argentina , Araña Viuda Negra , Femenino , Geografía , Ratones , Venenos de Araña/antagonistas & inhibidoresRESUMEN
Although the spiders of the genus Phoneutria cause envenomation and their presence has been described in several provinces of the north of Argentina, they are not as common as other spiders of sanitary importance. In the present work, we studied the toxicity of samples of venom of Phoneutria spiders from the provinces of Misiones (where severe envenomation and deaths by Phoneutria have been recorded) and Jujuy (where no deaths have been recorded and severe envenomations are not frequent). To this end, we assessed the lethal potency in mice and guinea pigs and the histopathological alterations caused by both venoms, as well as the neutralization by the commonly used therapeutic antivenom produced by the Butantan Institute in Brazil and by an experimental antivenom developed with venom of P. nigriventer from Misiones. There were no differences in the lethality of the venoms of spiders from both regions. Post mortem examination showed that the heart and lungs were the most affected organs, while important pulmonary edema was seen macroscopically. Histological analysis showed edema, atelectasis, emphysema and cardiac lesion in both experimental models. The antivenoms assayed showed good neutralization of the venoms in the two experimental models. Despite the different geographic origins, the venoms showed similar toxicity and both the experimental antivenom and therapeutic antivenmos were able to neutralize the venoms of Argentinean P. nigriventer.
Asunto(s)
Antivenenos/uso terapéutico , Venenos de Araña/toxicidad , Animales , Argentina , Cobayas , Corazón/efectos de los fármacos , Dosificación Letal Mediana , Pulmón/efectos de los fármacos , Pulmón/patología , Ratones , Miocardio/patologíaRESUMEN
BACKGROUND: The incidence and case fatality rate of snakebite in Argentina are poorly known. METHODS: The authors used questionnaires provided with antivenoms by the primary manufacturer of anti-venoms in Argentina. RESULTS: A total of 8083 completed questionnaires was collected between 1978 and 1998. The annual incidence of snakebite was 1.8 bites per 100,000 inhabitants, with a high geographical heterogeneity; in the northern provinces of the country, the incidence can exceed 150 snakebites per 100,000 people per year. Bothrops (pit viper) bites predominated, accounting for 96.6% (6720/6957) of envenomations, bites from Crotalus (rattlesnake) accounted for 2.8% (195/6957), and bites from Micrurus (coral snake) for 0.6% (42/6957). Most patients were young men, who were generally bitten during agricultural activities, i.e. while working in the fields. Most snakebites (78.9%, 5852/7419) were to the lower limb, including 58.3% (4322/7419) to the foot. The case fatality rate was <0.04% (3/8083). Most envenomations (90%, 7275/8083) were treated with specific antivenom during the first 4 h after the bite. The median dose of antivenom was two vials for viper bites (Bothrops and Crotalus) and three vials for Micrurus bites. CONCLUSION: These preliminary results should enable manufacturers to increase the availability of appropriate antivenom and health authorities to improve the management of snakebites where they are most common.