El Nino favors seasonal diseases

Changes in climate and rainfall patterns triggered by El Niño have even affected hunting regimes for certain animals that favor the transmission and spread of infectious diseases in Latin America and the Caribbean.

Polycystic echinococcosis can be fatal in the Amazon, a new study finds.

Experts say El Niño and its changing climate affect the incidence and distribution of vector-borne diseases such as rodents, mosquitoes and ticks.

El Niño warms water in the central and eastern equatorial Pacific Ocean, causing winds to weaken and large amounts of hot water not to circulate, releasing more heat into the atmosphere and favoring rainfall in the region. At the same time, in other areas, it will also trigger drought.

Although it formed in the Pacific Ocean, it affects climates around the world. In Latin America, El Niño led to increased temperatures and rainfall along the Pacific coast, southern and southeastern Brazil, and northern Argentina, while causing drought in Central America, parts of the Caribbean, and northern South America.

The Institute of Physics at the University of São Paulo in Brazil added that these changes affect the incidence of infectious diseases. However, he pointed out that it is difficult to say which will prevail because the weather is not the only factor. “The health risks associated with El Niño vary by region, country and time of year,” the institute said.

In addition to the direct effects of climate on health, the study also identified indirect factors. A recent study published in the Proceedings of the National Academy of Sciences of the United States of America finds that in parts of the pan-Amazonian region, El Niño events may disrupt hunting patterns of certain animals by local and rural populations, thereby favoring the spread of polycystic echinococcosis and spread.

The lesser-known disease is caused by Echinococcus wausii, a worm that commonly infects pacas and agouti, which are often hunted in the region.

Hunters often discard raw offal in the environment, or use it as food for domestic dogs, “these dogs become infected and eliminate the eggs in their feces, contaminating soil, food and water for human consumption,” says Fiocruz The foundation explained that the disease that the foundation studies occurs in northern Brazil.

The international study analyzed more than 400 cases of polycystic echinococcosis in the region and data on hunting activity recorded in 55 regions over the past 55 years.

“In some areas, the drought caused by this phenomenon may affect fisheries, forcing locals to hunt pacas and agouti, thus increasing the number of animals contaminated with Vogelia spp. Risk.” One of the authors of the article.

El Niño also produces heavy rainfall and flooding, and increases water-related diseases such as schistosomiasis, hepatitis A and diarrheal diseases.

These rainfalls also create stagnant pools where the Aedes aegypti mosquito grows, causing dengue, Zika and chikungunya.

The incidence of dengue fever has increased significantly over the past two decades. In 2000, there were 505,000 cases around the world, and in the first half of 2023, more than 3 million cases will be registered in the US alone.

Brazil has more than 2.3 million cases, followed by Peru (more than 215,000) and Bolivia (more than 133,000). Meanwhile, Argentina is experiencing its worst dengue outbreak, with 66 deaths and more than 129,000 cases reported in the latest epidemiological report.