Assessing the Increase of Snakebite Incidence in Relationship to Flooding Events

Abstract

Snakebite envenoming causes up to 138,000 deaths and 400,000 permanently disabled victims worldwide every year. Flooding is one of the many factors that seems to influence the incidence of snakebite. The catastrophic floods from late 2018 in Kerala (India) were widely broadcast and are an example of how flooding events are related to the increased incidence of snakebite. This relationship has been mentioned regularly in scientific and grey literature, but usually quite scarcely in comparison to other topics linked to snakebite. Additionally, web media, mobile communications, and social media have started playing an important role not only in providing access to information on flooding-related snakebite events, but also in snakebite prevention at a larger scale. In order to better understand to what extent the relationship between snakebite incidence and flooding is reported and quantified and appraise the importance of mobile communications and social media in snakebite prevention and management, we performed multiple searches in generic (Google) and specialized (PubMed, Web of Science, Google Scholar) databases. We retrieved 68 scientific articles and 5 reports ranging from 1892 to 2018 mentioning or analyzing flooding and the increased incidence of snakebite. Additionally, we found 68 web media reports linking flooding and snakebite. This review indicates that the increase of snakebite incidence due to flooding has been repeatedly observed all over the world. This phenomenon could be exacerbated because of climate change, which is expected to increase the overall magnitude and frequency of flooding. However, it could also be mitigated by the role the Internet, mobile communications, and social media could play in snakebite prevention and human and animal rescue strategies during flooding.

Novel transdisciplinary methodology for cross-sectional analysis of snakebite epidemiology at national scale

“…Recent studies have allowed to estimate human vulnerability to snakebite envenoming globally, by using proxy data on risk factors such as healthcare gaps, unavailability of antivenoms, and presence of medically important snake species [ 15 ], or through mathematical models [ 16 ], but without a direct measure of snakebite incidence and mortality. Additionally, new digital health applications have shown that it is partially possible to estimate areas of high snakebite incidence and identify populations at risk through citizen science [ 15 , 17 , 18 ] in countries where social media, citizen forums, and scientific online platforms are used to report snake-human encounters and map their geographic distributions [ 17 , 19 ].…”

Addressing the global snakebite crisis with geo-spatial analyses – Recent advances and future direction

“…As expected, snakebite incidence also correlates with measures of presence, activity, abundance, or diversity of snakes ( Bravo-Vega et al, 2019 ; Goldstein et al, 2021 ; Hansson et al, 2013 ; León-Núñez et al, 2020 ; Schneider et al, 2021 ; Suraweera et al, 2020 ; Yañez-Arenas et al, 2014 , 2016 ) or with variables that affect snake activity. Often snakebite incidence increases during certain seasons when snakes and farmers are both more active such as in rainy or harvest seasons ( Chippaux, 2017 ; Ediriweera et al, 2018 ; Goldstein et al, 2021 ; Hansson et al, 2010 ; Mohapatra et al, 2011 ; Molesworth et al, 2003 ; Patiño-Barbosa et al, 2019 ; Suraweera et al, 2020 ), during flooding events ( Ochoa et al, 2020 ), or at higher temperatures, lower altitudes, and higher precipitation ( Angarita-Gerlein et al, 2017 ; Chaves et al, 2015 ; Chippaux, 2017 ; Ediriweera et al, 2018 ; Ediriweera et al, 2016 ; Goldstein et al, 2021 ; Hansson et al, 2013 ; Schneider et al, 2021 ; Suraweera et al, 2020 , Table 2 ).…”

Implications of global environmental change for the burden of snakebite

“…Such relationships with precipitation are likely driven by demographic and activity patterns of snakes in response to precipitation levels ( Chaves et al, 2015 ), and precipitation is also known to influence the composition of local venomous snake ensembles. Furthermore, flooding events are widely considered a primary driver of snakebite risk as they wash snakes towards lowlands which usually have higher population density ( Ochoa et al, 2020 ). On the other hand, the positive effect of temperature on snakebites may be related to overall diversity ( Luiselli et al, 2020 ).…”

“…However, short term flooding events, such as monsoons, have been observed to lead to large numbers of snakebites by putting humans and snakes in proximity. The most likely mechanisms could be related to snakes being dragged by floodwaters from their natural home ranges or distributions (as has been the case of C. durissus in brazil; Bastos et al, 2005 ), to areas with higher human populations, and then seeking shelter from deep water in higher grounds along with people ( Ochoa et al, 2020 ). As climate change is altering the frequency, severity and location of flooding events, snakebite burden is expected to keep changing with flooding events.…”

“…The scarcity of examples of environmental change impacts on snakebite shows that snakebite eco-epidemiology has a long way to go, especially with regards to characterizing snakebite statistics in relation to ecological determinants of risk patterns, such as those described for flooding events ( Ochoa et al, 2020 ). As shown previously along this review untangling the latter is possible although, doing so at a global scale is an enormous but necessary challenge.…”