Extreme weather events (EWEs) often create conditions conducive to outbreaks of infectious diseases. The upsurge of insect, rodent and water-borne diseases following Hurricane Mitch in Central America in October, 1998 highlights this connection. Heavy rains can produce new breeding sites for insects, drive rodents from burrows and contaminate clean water systems. Conversely, flooding followed by drought can spread fungal spores and spark fires.
The 1997/98 El Niño-related extreme weather events spawned "clusters" of disease outbreaks in many regions of the globe. In the Horn of Africa extensive flooding led to large outbreaks of malaria, Rift Valley fever and cholera. In Latin America, extreme weather was associated with outbreaks of malaria, dengue fever and cholera. In Indonesia and surrounding island nations, delayed monsoons - and the compounding effects of local farming practices - led to prolonged fires, widespread respiratory illness, and significant losses of wildlife.
Throughout the 1990s an area the size of Massachusetts has burned each year in the Amazon. During 1997/98 tropical rainforests in Brazil, Mexico and Central America - normally soaked and relatively immune to forest fires - raged out of control. Winds brought the smoke from tens of thousands of Mexican fires - the largest forest fire complex on record for Mexico - in a great gyre through the southern U.S.. 500,000 acres later erupted in Florida; 100,000 people were evacuated and 300 homes were lost (Pyne 1998). The losses to Florida in timber alone were over $400 million. Flooding in California spawned agricultural pests and brought large economic losses. In Europe and the U.S., 1998 summer heatwaves killed hundreds.
The 1998 La Niña event- beginning abruptly in the Spring of '98 - continued the pattern of extreme weather. All told 1998, the warmest year on record - and perhaps of the millennium (Warwick 1998) - proved to be the most costly year on record in weather-related impacts. In the first 11 months of 1998, $89 billion was lost due to weather-related events; more than all the combined losses of the 1980s. If climate change continues to be associated with more frequent and intense El Niño and La Niña events - and the accompanying volatile and severe weather patterns - we have begun to see the profound consequences climate change can have for public health and for the international economy.
There are implications for monitoring, public health early warning systems and for environmental and energy policies.