Increase in the risk of snakebites incidence due to changes in humidity levels: A time series study in four municipalities of the state of Rondônia

Abstract

Introduction: Snakebites represent a serious global public health problem, especially in tropical countries. In Brazil, the incidence of snakebites ranges from 19 to 22 thousand cases per 100000 persons annually. The state of Rondônia, in particular, has had an increasing incidence of snakebites. Methods: A retrospective cross-sectional study on snakebites was conducted from January 2007 to December 2018. Brazil's Information System for Notifiable Diseases was queried for all snakebites reported in Porto Velho, Ariquemes, Cacoal, and Vilhena. Data on land surface temperatures during the day and night, precipitation, and humidity were obtained using the Google Earth Engine. A Bayesian time series model was constructed to describe the pattern of snakebites and their relationship with climate data. Results: In total, 6326 snakebites were reported in Rondônia. Accidents were commonly caused by Bothrops sp. (n=2171, 81.80%). Snakebites most frequently occurred in rural areas (n=2271, 85.5%). Men, with a median age of 34 years (n=2101, 79.1%), were the most frequent bitten. Moderate clinical manifestation was the most common outcome of an accident (n=1101, 41.50%). There were clear seasonal patterns with respect to rainfall, humidity, and temperature. Rainfall and land surface temperature during the day or night did not increase the risk of snakebites in any city; however, changes in humidity increased the risk of snakebites in all cities. Conclusion: This study identified the population exposed to snakes and the influence of anthropic and climatic factors on the incidence of snakebites. According to climate data, changes in humidity increased the risk of snakebites.

Snakebites in Rio Branco and surrounding region, Acre, Western Brazilian Amazon

“…The snakebites analyzed in the present study had a greater occurrence during the rainy season (64,24%) and the historical series (2009-2018) was statistically associated with the low seasonal river levels and rainfall, thus confirming the observations of other studies 3 , 6 , 8 , 11 , 22 - 24 . This predominance of snakebites in the wettest months is probably related to the increase in snake activity in this period, due to the greater availability of prey and reproductive activities 25 , 26 .…”

Snakebite envenoming in humanitarian crises and migration: A scoping review and the Médecins Sans Frontières experience

“…One study in Thailand mentions the increased incidence of snakebite in children during floods ( Laohawiriyakamol et al, 2011 ). In Brazil a time-series study analyzing rainfall and humidity levels over years concluded that increased humidity (rather than rainfall) is related to increased snakebite yearly admissions ( Ferreira et al, 2020 ).…”

Review of Geospatial Technology for Infectious Disease Surveillance: Use Case on COVID-19

“…Such geographical link with diseases leads to the challenge of spatial mapping of disease transmission which overcame through the branches of biodiversity science—ecology and biogeography. Such approach of ecological and biogeographical modelling can be seen from various studies on disease transmission risks mapping, for example, Arboleda et al ( 2009 ), Deka and Morshed ( 2018 ), Ferreira et al ( 2020 ), Holt et al ( 2009 ), Mweya et al ( 2013 ), Nakazawa et al ( 2013 ), Reeves et al ( 2015 ), Samy et al ( 2014 ), Qian et al ( 2014 ), Zhao et al ( 2016 ), Zhu et al ( 2017 ).…”