El Niño

Parts of the planet warm and cool during El Niño and La Niña. And infectious [diseases:viruses] also wax and wane in step with the climate cycle. Take malaria - shown to spike in northern Venezuela during cool, La Niña conditions. Or flu pandemics, which often follow months after La Niña sets in. Now researchers have linked another public health risk to El Niño climate cycling: poisonous viper bites.Their study area was Costa Rica - where health centers keep rigorous records on snakebites. They [compared:matched] nine years of those snakebite records - including some 6,500 bites - to climate data over the same period. And they found that [snakebites:vaporise] were two to three times as prevalent in the hottest and coldest years of the El Niño climate cycle.Sounds counterintuitive, right - you might expect the climate extremes to have opposite effects. But the researchers say in hot, dry years, plant productivity peaks, driving an [increase:rise] in the number of rodents - aka snake food - [potentially:possibly] increasing the number of snakes.