Crab fisherman communities in north Brazil: a new high risk population for vampire bat rabies
Authors: Paula Silva Nailde de , Andrade Elane Araújo , Cardoso Denis , Souza Guimarães Ruth de , Silva Mateus Borges , Gomes Nascimento Kelly Karoline , Arruda Xavier Diego de , Abel Isis 
Published: March 2019

An outbreak of human rabies transmitted by hematophagous bats occurred in 2018 in the state of Pará, Brazil, eastern Amazon, after 14 years with no record of the disease. It is necessary to understand the epidemiological characteristics of these attacks to protect the local population. This study aimed to characterize attacks of humans by vampire bats in the municipality of São João da Ponta, Pará state, Brazil, from 2013 to 2015. All individuals attacked by bats who sought medical care during the study period (n=5) were identified in the Notifiable Diseases Information System (SINAN) database and answered a questionnaire about the circumstances of the attack. Using snowball sampling, seed cases identified other individuals who were attacked in the same period but did not seek medical care (n=61), totalizing 66 people attacked in the same period. The interviewees were male (92.4%), adults between 20 and 50 years old (69.6%) and had completed elementary education (86.3%). Most were rural residents (92.4%) and crab fishermen (79.3%). The interviewees (92.4%) identified the mangrove of the Mãe Grande de Curuçá extractive reserve as an area conducive to attacks by vampire bats, where groups of fishermen sometimes concentrate for days for crab fishing, often living in improvised dwellings without walls and covered by tarps or straw (88.8%). The wounds were single bites (71.2%) and were located on the lower limbs (93.9%). Overall, 42.4% of participants had been bitten more than four times throughout their life (range 1-23 attacks). Participants were unaware of the risk of contracting rabies by the bite (95.4%). Using São João da Ponta as a model, this study shows that bat attacks are an essentially occupational problem in the study region. Indeed, for each reported attack, there are 12.2 unreported cases. It is necessary to develop strategies to reach this population for prophylactic treatment.

Author Summary

Different from which occurs worldwide in relation to rabies transmission, in Amazon region, vampire bat is involved on direct transmission of rabies virus to humans when searching for bloodmeal. It is common in the state of Pará, Eastern Amazon, large areas inhabited near forests and mangroves. People living there use forest natural resources as a way of income and sustenance and these working conditions is what our study points out as an important factor for aggressions predisposition. Here this subject is shown as an occupational problem. This study also quantified for the first time underreported human’s aggressions by bats in Amazon, using the snowball sampling, which valued the relationship between individuals to reach the target population. Based on these results, rabies surveillance may direct actions for prevention and health education for these individuals, including changes in notifications forms and suggesting pre-exposure prophylaxis in vaccination calendar of the Brazilian Ministry of Health for these individuals exposed to the rabies virus.