Argentina ? Recent heavy rains in South America have killed dozens of people, wiped out thousands of homes and triggered outbreaks of dengue fever in several countries.

The floods have hit Bolivia hardest, where flooding has killed more than 40 people, destroyed nearly a half-million acres of farmland and forced tens of thousands to flee their homes.

Bolivian army officials announced this week that more than 77,000 families have been affected by the floods since December, mostly in the low-lying Amazon flood plains of the Beni province. Flooding in northern Argentina has also resulted in hundreds of evacuations in recent days.

The heavier-than-normal rains early this year are blamed on an El Nino weather cycle – a periodic warming of tropical Pacific Ocean waters that causes severe weather every several years, particularly in the Southern Hemisphere.

The rains also have indirectly contributed to a public health crisis in Paraguay, where an outbreak of mosquito-borne dengue fever in recent weeks has killed 10 people and sickened thousands more. Standing rainwater helped create prime breeding grounds for the mosquitoes that carry the virus, according to health experts.