Epidemiological and clinical aspects of snakebite in Belo Horizonte, southeast Brazil

Adjusting for spatial variation when assessing individual-level risk: A case-study in the epidemiology of snake-bite in Sri Lanka

Background

Health outcomes and causality are usually assessed with individual level sociodemographic variables. Studies that consider only individual-level variables can suffer from residual confounding. This can result in individual variables that are unrelated to risk behaving as proxies for uncaptured information. There is a scarcity of literature on risk factors for snakebite. In this study, we evaluate the individual-level risk factors of snakebite in Sri Lanka and highlight the impact of spatial confounding on determining the individual-level risk effects.

Methods

Data was obtained from the National Snakebite Survey of Sri Lanka. This was an Island-wide community-based survey. The survey sampled 165,665 individuals from all 25 districts of the country. We used generalized linear models to identify individual-level factors that contribute to an individual’s risk of experiencing a snakebite event. We fitted separate models to assess risk factors with and without considering spatial variation in snakebite incidence in the country.

Results

Both spatially adjusted and non-adjusted models revealed that middle-aged people, males, field workers and individuals with low level of education have high risk of snakebites. The model without spatial adjustment showed an interaction between ethnicity and income levels. When the model included a spatial adjustment for the overall snakebite incidence, this interaction disappeared and income level appeared as an independent risk factor. Both models showed similar effect sizes for gender and age. HEmployment and education showed lower effect sizes in the spatially adjusted model.

Conclusions

Both individual-level characteristics and local snakebite incidence are important to determine snakebite risk at a given location. Individual level variables could act as proxies for underling residual spatial variation when environmental information is not considered. This can lead to misinterpretation of risk factors and biased estimates of effect sizes. Both individual-level and environmental variables are important in assessing causality in epidemiological studies.

Use of EDTA in the treatment of local tissue damage caused by the Bothrops alternatus venom

ABSTRACT Twelve adult rabbits were distributed in three groups and received on the femoral biceps region, via intradermal injection (ID), 25µg of Bothrops alternatus venom dissolved in NaCl 0.9% and diluted in 0.25mL of phosphate buffered saline (PBS). Thirty minutes later, the group G1 received 0.25mL of phosphate buffered saline (PBS) ID while to G2 and G3 25mg of ethylenediamine tetraacetic acid (EDTA) dissolved in 0.25mL of PBS were administered via intramuscular (IM) and intravenous (IV) injection, respectively. Evaluations included local lesion and blood profile of all animals, before (time zero) and at 1, 2, 3, 4, 5, 6, 12, 18 and 24h after venom administration. All animal treated with PBS (G1) and EDTA IV (G3) presented increase of nociceptive stimuli at the site of inoculation of the venom, followed by moderate edema that persisted for 24h. Animals treated with IM EDTA (G2) only manifested increase of nociceptive stimuli at the site of injection 1h after treatment with discrete local edema between 12 and 24h. In relation to the local hemorrhagic halo no differences were found amongst the studied groups. Blood profile revealed significant decrease of segmented neutrophils in all groups. There was also increase in triglycerides and decrease in total protein and albumin in all groups. The local lesion was not altered by the treatments.

Injuries caused by venomous animals and folk medicine in farmers from Cuité, State of Paraiba, Northeast of Brazil

Injuries caused by venomous animals reported by the agricultural workers from the municipality of Cuité, Curimataú region of Paraiba State, Northeast of Brazil, and the practices of folk medicine which they use to treat these cases were studied in this work from June to August 2010. The farmers studied aged from 11 to 90 years. The number of people who reported cases of injury by these animals in their families was high (89.3%). Scorpions, wasps, bees and snakes were the most cited and the extremities of the body (hands, feet, legs and head) were the most affected. The practice of folk medicine to treat these injuries includes various procedures ranging from ritualistic treatments, use of animals or parts of them, and some herbal preparations. The folk treatment was reported as effective by most of the workers injured (63.9%). Body parts of dead snakes are used in various zootherapic treatments. In the imaginary of the agricultural workers the venomous animals are considered hazardous (48.7%) or disgusting (11.3%), and several parts of such animals as the rattle, bee sting or snake leather are used as amulet. Several legends have also been reported about snakes, scorpions and bees. The need for educational activities that aim to clarify these workers about the dangers of such practices is urgent.

Perfil dos acidentes ofídicos no norte do Estado de Minas Gerais, Brasil

O objetivo deste estudo foi descrever o perfil epidemiológico dos acidentes ofídicos da macrorregião de saúde do Norte do Estado de Minas Gerais, Brasil. Foram analisadas informações sobre os acidentes ofídicos relativos ao período compreendido entre janeiro de 2002 a dezembro de 2006, por meio de bancos de dados. Os resultados demonstraram 10.553 casos notificados, com ênfase para a maior casuística em meses de tempo quente e chuvoso, em áreas urbanas (54,1%), faixa etária menor de 20 anos (39,7%), acometendo mais homens e estudantes (53,1% e 29,1%) respectivamente. Os membros inferiores (pé, dedo do pé, perna e coxa) foram os locais mais afetados (35,9%), as serpentes prevalentes foram do gênero Bothrops (82,9%) e a gravidade da maioria dos acidentes foi leve (66,2%). Observou-se nesse estudo um importante impacto da sazonalidade, urbanização, subnotificação das espécies envolvidas nesses acidentes e busca rápida pelo pronto atendimento. Espera-se que os dados inéditos da casuística obtida possam servir de substrato para o planejamento e execução de medidas voltadas para vigilância em saúde e atendimento.

Características clínicoepidemiológicas dos acidentes ofídicos em Rio Branco, Acre

Com o objetivo de determinar o perfil clínico-epidemiológico dos acidentes ofídicos, em hospital do Estado do Acre, foram estudados prospectivamente 144 pacientes admitidos no período de janeiro a dezembro de 2002. Desses, 113 (78,5%) foram classificados como vítimas de acidente com envenenamento. Os gêneros Bothrops, Lachesis e Micrurus foram responsáveis por, respectivamente, 75,7%, 2,1% e 0,7% dos casos. Os acidentes predominaram em pessoas do sexo masculino (78,5%), trabalhadores rurais (51,4%) e com idades entre 10 e 29 anos (43,8%). Nos acidentes botrópicos, os envenenamentos considerados moderados (48,6%) prevaleceram sobre os leves (31,2%) e graves (20,2%). Dois casos envolvendo o gênero Bothrops não receberam terapia antipeçonha. Entretanto, soro heterólogo foi administrado em 23 vítimas de acidente sem envenenamento. Concluindo, os resultados obtidos neste estudo diferiram dos observados por outros autores quanto à gravidade dos casos e adequação do tratamento, indicando a necessidade de treinamento da equipe.

[Snake bite epidemiology in the last 100 years in Brazil: a review]

We review 30 studies on snake bites in Brazil, published from 1901 to 2000, and conclude that epidemiological analyses conducted in the last 100 years are based on the same variables already identified by Vital Brazil in his pioneering report, i.e., characteristics of the individuals prone to snake bites, the bites themselves, and treatment. The original epidemiological profile was also maintained over the years and indicates that such accidents are more frequent among male farm workers in the 15-49-year age bracket, affecting mainly the lower limbs, and caused by snakes from genus Bothrops.

Aspectos epidemiológicos e clínicos dos acidentes ofídicos ocorridos nos municípios do Estado do Amazonas

No Amazonas, o acidente ofídico é um problema de saúde pública pouco conhecido. Por este motivo, foi realizado um estudo descritivo dos acidentes ofídicos atendidos nas Unidades de Saúde de 34 municípios, um distrito e dois pelotões de fronteira do Estado do Amazonas. As características mais comuns encontradas dentre os pacientes foram: agricultor (50,4%), do sexo masculino (81,3%), em idade produtiva (72,1%), picado no membro inferior (88,5%), por jararaca (48,6%) ou surucucu (46,8%), na zona rural de seu município (70,2%) e que só recebeu atendimento médico em tempo superior a seis horas, após acidente (57,3%). As manifestações locais mais freqüentes foram: edema (76,9%), dor (68,7%), eritema (10,2%) e hemorragia (9,3%). Hemorragia (18,8%) foi a manifestação sistêmica mais freqüente. O antiveneno foi administrado em apenas 65,9% dos pacientes. A via mais utilizada foi a endovenosa (52,3%), sendo relevante o uso de vias não mais recomendadas (47,7%). O antiveneno administrado, na maioria dos pacientes, foi o antibotrópico (66,7%). As complicações mais freqüentes foram abcesso (13,7%), necrose (12,3%), infecção secundária (8,3%), insuficiência renal (2,5%) e gangrena (2,5%). Os procedimentos médicos mais usados para o tratamento das complicações foram: drenagem (52,6%), debridamento (28,9%), amputação (10,5%), limpeza cirúrgica (5,3%) e diálise peritoneal (2,6%). A letalidade foi de 1%.