An unusually potent outbreak of dengue fever has killed 26 people and infected nearly 40,000 more so far this year in Central America, where the mosquito-born illness is endemic.
Honduras has seen the most fatalities, with 15, followed by Nicaragua, with five. The highest number of infections has been recorded in Costa Rica, with 17,000.
Only Panama has so far been spared this year, with just 300 cases and no deaths.
With a warm and humid climate and powerful rainy seasons, Central America is an ideal region for the mosquitoes that carry the virus.
Like many countries in the region, Honduras, which has seen 12,000 cases of dengue fever this year, has been working to mobilize the population to limit the spread of mosquitoes.
The government program has been using the slogan, "Without breeding, there are no mosquitoes. Without mosquitoes, there is no dengue."
But authorities say initiatives to eliminate the standing water where mosquitoes lay their eggs have met with only limited success.
In nearby Costa Rica, where three have already died this year, a health official says people are not taking the issue seriously.
"Spraying does not help much if we don't eliminate the mosquito breeding sites," said Costa Rica's top health official Roberto Castro, "but not in all cases do the neighbors respond."
Honduras, Costa Rica, Nicaragua and El Salvador issued formal dengue alerts earlier this month, while Guatemala and Panama officials said they were monitoring the disease, which normally spreads more easily later in the rainy season.
Health authorities said they have been baffled by this recent outbreak, which has occurred despite a spate of unusually dry weather.
Dengue affects between 50 and 100 million people in the tropics and subtropics each year, resulting in fever, muscle and joint ache.
The disease is caused by four strains of virus that are spread by the mosquito Aedes aegypti.
There is no vaccine, so medical authorities in the region, where poverty is widespread, have been trying to stamp it out by focusing on mosquito control.
The illness can be fatal, developing into hemorrhagic fever, which can lead to shock and internal bleeding.