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Snakebites are associated with poverty, weather fluctuations, and El Niño.

Chaves LF, Chuang TW, Sasa M, Gutiérrez JM - Sci Adv (2015)

Bottom Line: We emphasize El Niño Southern Oscillation (ENSO), a climatic phenomenon associated with cycles of other neglected tropical diseases (NTDs) in the region and elsewhere.We found that periodicity in snakebites reflects snake reproductive phenology and is associated with ENSO.Nevertheless, snakebites cluster in Costa Rican areas with the heaviest rainfall, increase with poverty indicators, and decrease with altitude.

View Article: PubMed Central - PubMed

Affiliation: Nagasaki University Institute of Tropical Medicine (NEKKEN), Sakamoto 1-12-4, Nagasaki, Japan. ; Program for Tropical Disease Research (PIET), School of Veterinary Medicine, National University of Costa Rica, P.O. Box 304-3000, Heredia, Costa Rica.

ABSTRACT
Snakebites are environmental and occupational health hazards that mainly affect rural populations worldwide. The ectothermic nature of snakes raises the issue of how climate change's impact on snake ecology could influence the incidence of snakebites in humans in ways that echo the increased predation pressure of snakes on their prey. We thus ask whether snakebites reported in Costa Rica from 2005 to 2013 were associated with meteorological fluctuations. We emphasize El Niño Southern Oscillation (ENSO), a climatic phenomenon associated with cycles of other neglected tropical diseases (NTDs) in the region and elsewhere. We ask how spatial heterogeneity in snakebites and poverty are associated, given the importance of the latter for NTDs. We found that periodicity in snakebites reflects snake reproductive phenology and is associated with ENSO. Snakebites are more likely to occur at high temperatures and may be significantly reduced after the rainy season. Nevertheless, snakebites cluster in Costa Rican areas with the heaviest rainfall, increase with poverty indicators, and decrease with altitude. Altogether, our results suggest that snakebites might vary as a result of climate change.

No MeSH data available.


Related in: MedlinePlus

Variables spatially associated with snakebites in CR.(A) Altitude. (B) Rainfall. (C) Poverty gap index. (D) Destitute housing. Coefficients are shown (in the legend of each panel) only when pseudo t values are significant (P < 0.05).
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Figure 2: Variables spatially associated with snakebites in CR.(A) Altitude. (B) Rainfall. (C) Poverty gap index. (D) Destitute housing. Coefficients are shown (in the legend of each panel) only when pseudo t values are significant (P < 0.05).

Mentions: Figure 2 shows the spatial distribution of factors that might be associated with snakebites and their spatial relationship stratified by geographically weighted regression (GWR). We considered elevation (Fig. 2A) as a proxy for temperature, which linearly decreases with altitude (17) and rainfall (Fig. 2B), both being major environmental factors associated with terciopelo abundance and activity (9). Poverty gap index (Fig. 2C) and percentage of destitute housing (Fig. 2D) were analyzed to account for socioeconomic factors that might determine the occurrence of snakebites, as observed for other NTDs in CR (17). Results from GWR showed a negative association between average canton elevation and the cumulative number of snakebites (Fig. 2A). Rainfall demonstrated different impacts on snakebites. In wetter regions (Southern Pacific basin), higher precipitation was negatively associated with snakebites (Fig. 2B). In contrast, high precipitation in drier regions (Northern Pacific basin) increased the risk of snakebites (Fig. 2B). Overall, a high poverty gap index was predictive of snakebites (Fig. 2C), and a similar pattern was observed for the percentage of destitute housing, especially in rural areas (Fig. 2D). GWR was highly successful in explaining snakebite spatial patterns because 82% of the deviance was explained by the model (local deviance explanation ranged from 0.47 to 0.88), with the best performance observed in the Pacific basin of CR (fig. S2 and table S1), where snakebite hotspots occur (Fig. 1B and fig. S4).


Snakebites are associated with poverty, weather fluctuations, and El Niño.

Chaves LF, Chuang TW, Sasa M, Gutiérrez JM - Sci Adv (2015)

Variables spatially associated with snakebites in CR.(A) Altitude. (B) Rainfall. (C) Poverty gap index. (D) Destitute housing. Coefficients are shown (in the legend of each panel) only when pseudo t values are significant (P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643785&req=5

Figure 2: Variables spatially associated with snakebites in CR.(A) Altitude. (B) Rainfall. (C) Poverty gap index. (D) Destitute housing. Coefficients are shown (in the legend of each panel) only when pseudo t values are significant (P < 0.05).
Mentions: Figure 2 shows the spatial distribution of factors that might be associated with snakebites and their spatial relationship stratified by geographically weighted regression (GWR). We considered elevation (Fig. 2A) as a proxy for temperature, which linearly decreases with altitude (17) and rainfall (Fig. 2B), both being major environmental factors associated with terciopelo abundance and activity (9). Poverty gap index (Fig. 2C) and percentage of destitute housing (Fig. 2D) were analyzed to account for socioeconomic factors that might determine the occurrence of snakebites, as observed for other NTDs in CR (17). Results from GWR showed a negative association between average canton elevation and the cumulative number of snakebites (Fig. 2A). Rainfall demonstrated different impacts on snakebites. In wetter regions (Southern Pacific basin), higher precipitation was negatively associated with snakebites (Fig. 2B). In contrast, high precipitation in drier regions (Northern Pacific basin) increased the risk of snakebites (Fig. 2B). Overall, a high poverty gap index was predictive of snakebites (Fig. 2C), and a similar pattern was observed for the percentage of destitute housing, especially in rural areas (Fig. 2D). GWR was highly successful in explaining snakebite spatial patterns because 82% of the deviance was explained by the model (local deviance explanation ranged from 0.47 to 0.88), with the best performance observed in the Pacific basin of CR (fig. S2 and table S1), where snakebite hotspots occur (Fig. 1B and fig. S4).

Bottom Line: We emphasize El Niño Southern Oscillation (ENSO), a climatic phenomenon associated with cycles of other neglected tropical diseases (NTDs) in the region and elsewhere.We found that periodicity in snakebites reflects snake reproductive phenology and is associated with ENSO.Nevertheless, snakebites cluster in Costa Rican areas with the heaviest rainfall, increase with poverty indicators, and decrease with altitude.

View Article: PubMed Central - PubMed

Affiliation: Nagasaki University Institute of Tropical Medicine (NEKKEN), Sakamoto 1-12-4, Nagasaki, Japan. ; Program for Tropical Disease Research (PIET), School of Veterinary Medicine, National University of Costa Rica, P.O. Box 304-3000, Heredia, Costa Rica.

ABSTRACT
Snakebites are environmental and occupational health hazards that mainly affect rural populations worldwide. The ectothermic nature of snakes raises the issue of how climate change's impact on snake ecology could influence the incidence of snakebites in humans in ways that echo the increased predation pressure of snakes on their prey. We thus ask whether snakebites reported in Costa Rica from 2005 to 2013 were associated with meteorological fluctuations. We emphasize El Niño Southern Oscillation (ENSO), a climatic phenomenon associated with cycles of other neglected tropical diseases (NTDs) in the region and elsewhere. We ask how spatial heterogeneity in snakebites and poverty are associated, given the importance of the latter for NTDs. We found that periodicity in snakebites reflects snake reproductive phenology and is associated with ENSO. Snakebites are more likely to occur at high temperatures and may be significantly reduced after the rainy season. Nevertheless, snakebites cluster in Costa Rican areas with the heaviest rainfall, increase with poverty indicators, and decrease with altitude. Altogether, our results suggest that snakebites might vary as a result of climate change.

No MeSH data available.


Related in: MedlinePlus