title: Older Age and Time to Medical Assistance Are Associated with Severity and Mortality of Snakebites in the Brazilian Amazon: A Case-Control Study.
abstract: The Amazon region reports the highest incidence of snakebite envenomings in Brazil. We aimed to describe the epidemiology of snakebites in the state of Amazonas and to investigate factors associated with disease severity and lethality. We used a nested case-control study, in order to identify factors associated with snakebite severity and mortality using official Brazilian reporting systems, from 2007 to 2012. Patients evolving to severity or death were considered cases and those with non-severe bites were included in the control group. During the study period, 9,191 snakebites were recorded, resulting in an incidence rate of 52.8 cases per 100,000 person/years. Snakebites mostly occurred in males (79.0%) and in rural areas (70.2%). The most affected age group was between 16 and 45 years old (54.6%). Fifty five percent of the snakebites were related to work activities. Age ≤15 years [OR=1.26 (95% CI=1.03-1.52); (p=0.018)], age ≥65 years [OR=1.53 (95% CI=1.09-2.13); (p=0.012)], work related bites [OR=1.39 (95% CI=1.17-1.63); (p<0.001)] and time to medical assistance >6 hours [OR=1.73 (95% CI=1.45-2.07); (p<0.001)] were independently associated with the risk of severity. Age ≥65 years [OR=3.19 (95% CI=1.40-7.25); (p=0.006)] and time to medical assistance >6 hours [OR=2.01 (95% CI=1.15-3.50); (p=0.013)] were independently associated with the risk of death. Snakebites represent an occupational health problem for rural populations in the Brazilian Amazon with a wide distribution. These results highlight the need for public health strategies aiming to reduce occupational injuries. Most cases of severe disease occurred in the extremes of age, in those with delays in medical attention and those caused by Micrurus bites. These features of victims of snakebite demand adequate management according to well-defined protocols, including prompt referral to tertiary centres when necessary, as well as an effective response from surveillance systems and policy makers for these vulnerable groups.
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: Esaú L
authors.initials: EL
authors.lastname: Feitosa
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil; Núcleo de Sistemas de Informação, Fundação de Vigilância em Saúde do Amazonas, Manaus, Brazil.
authors.forename: Vanderson S
authors.initials: VS
authors.lastname: Sampaio
authors.affiliation: Department of Medicine, Emory University, Atlanta, United States of America.
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Salinas
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Queiroz
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: Iran Mendonça
authors.initials: IM
authors.lastname: da Silva
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: André A
authors.initials: AA
authors.lastname: Gomes
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Sachett
authors.affiliation: Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: André M
authors.initials: AM
authors.lastname: Siqueira
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: Luiz Carlos L
authors.initials: LC
authors.lastname: Ferreira
authors.affiliation: Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, Brazil.
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Dos Santos
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil; Instituto Leônidas & Maria Deane, Fundação Oswaldo Cruz, Manaus, Brazil.
authors.forename: Marcus
authors.initials: M
authors.lastname: Lacerda
authors.affiliation: Departamento de Ensino e Pesquisa, Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, Brazil; Escola Superior de Ciências da Saúde, Universidade do Estado do Amazonas, Manaus, Brazil.
authors.forename: Wuelton
authors.initials: W
authors.lastname: Monteiro
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000818:Animals; D017837:Bothrops; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D012909:Snake Bites / Q000453:epidemiology / Q000401:mortality* / Q000628:therapy; D013997:Time Factors; D017819:Viperidae; D055815:Young Adult