Climate change may cut plague cases in U.S.: study

OSLO (Reuters) – Rare outbreaks of plague in the United States seem to match climate shifts over the Pacific Ocean in a hint that global warming may make the region too hot and dry for the disease, scientists said on Wednesday.

Feared as the “Black Death” of the 14th century that killed an estimated 50 million people, plague is still a threat mainly in Africa. The western United States has had 430 cases since 1950, or about seven per year.

The scientists, based in Norway, the United States and Sweden, said the number of U.S. infections seemed to vary with a natural shift between warm and cool ocean conditions known as the Pacific Decadal Oscillation (PDO) that can last 20-30 years.

Until now, researchers had been unable to explain swings in the number of cases — ranging from 40 in 1983 at a warm part of the PDO to almost none in the 1950s, a cool phase. The plague bacteria is spread to humans by fleas living on rats.

Reuters