Geographic variation of individual venom profile of Crotalus durissus snakes

Background:

South American rattlesnakes are represented in Brazil by a single species, Crotalus durissus, which has public health importance due to the severity of its envenomation and to its wide geographical distribution. The species is subdivided into several subspecies, but the current classification is controversial. In Brazil, the venoms of C. d. terrificus and C. d. collilineatus are used for hyperimmunization of horses for antivenom production, even though the distinction of these two subspecies are mostly by their geographical distribution. In this context, we described a comparative compositional and functional characterization of individual C. d. collilineatus and C. d. terrificus venoms from three Brazilian states.

Methods:

We compared the compositional patterns of C. d. terrificus and C. d. collilineatus individual venoms by 1-DE and RP-HPLC. For functional analyzes, the enzymatic activities of PLA₂, LAAO, and coagulant activity were evaluated. Finally, the immunorecognition of venom toxins by the crotalic antivenom produced at Butantan Institute was evaluated using Western blotting.

Results:

The protein profile of individual venoms from C. d. collilineatus and C. d. terrificus showed a comparable overall composition, despite some intraspecific variation, especially regarding crotamine and LAAO. Interestingly, HPLC analysis showed a geographic pattern concerning PLA₂. In addition, a remarkable intraspecific variation was also observed in PLA₂, LAAO and coagulant activities. The immunorecognition pattern of individual venoms from C. d. collilineatus and C. d. terrificus by crotalic antivenom produced at Butantan Institute was similar.

Conclusions:

The results highlighted the individual variability among the venoms of C. durissus ssp. specimens. Importantly, our data point to a geographical variation of C. durissus ssp. venom profile, regardless of the subspecies, as evidenced by PLA₂ isoforms complexity, which may explain the increase in venom neurotoxicity from Northeastern through Southern Brazil reported for the species.

[Certificates of live birth: analysis of completion in the city of Ribeirão Preto, São Paulo, Brazil]

The study aims to identify the frequency with which certificates of live birth are filled out and to analyze the data they provide. To gather the data, the authors used a model birth certificate filled out by research assistants based on information obtained from the reports on mothers and newborns. This information was then compared to data contained in the official birth certificates available in the Information Technology Division of the Municipal Health Department. The sample consisted of 911 certificates of live birth from July 1996 in the ten maternity wards of the city of Ribeirão Preto. Data analysis showed that frequency of completion of birth certificates differs by hospital, involving both physicians and administrative personnel. The authors identified a high level of agreement in the data, i.e., over 90% in 13 of 18 variables compared in the birth certificates and in half of the hospitals investigated. The disagreement occurred especially with respect to data on the number of children per mother, number of prenatal visits, mother's schooling, and father's name.