WASHINGTON – The Pan American Health Organization says Latin America will have between 2 million and 3 million Zika cases, warning that the 100,000 cases reported thus far do not reflect the magnitude of the situation because many infected people with either no symptoms or very mild ones do not go to the doctor.
“That figure does not represent the scope we think Zika has. We need better diagnostic tests. Brazil has already estimated that it will have 1.3 million (cases) and Colombia a half million,” Marcos Espinal, the director of PAHO’s Department of Communicable Diseases and Health Analysis, said Friday at the American Association for the Advancement of Science’s annual meeting in Washington.
The expert based his estimate on Latin America’s 2015 tally of 2.3 million cases of dengue and 600,000 of chikungunya – viral diseases that, like Zika, are transmitted by the Aedes aegypti mosquito.
“It wouldn’t surprise me if we had 2 or 3 million Zika cases because we’re seeing that the mosquito transmits (that disease) as or more effectively than chikungunya,” Espinal said.
Latin America is the region hardest hit by the current Zika epidemic, accounting for 26 of the 30 countries and territories where local transmission of the virus has been reported.
“The entire population is at risk because the virus is new in the hemisphere, and therefore no one has immunity,” Espinal said.
The expert stressed, however, that it was still too early to say that Zika was the direct cause of a surge in Brazil in the number of babies born with abnormally small heads, a condition known as microcephaly.
“We can only talk about a potential link. Brazil and Colombia are conducting case studies that will tell us a lot about this question,” Espinal said.
The World Health Organization’s director of strategy, Christopher Dye, said for his part that “the case for a causal link” between Zika and microcephaly “is quite strong.”
“We should now say that Zika is guilty until proven innocent,” he added.
Dye said there would be many more microcephaly cases in Latin America, although he acknowledged that it was impossible at this time to offer a more precise prediction.
Brazil has reported 4,000 cases of microcephaly, and the number of cases in Latin America is going to rise, Dye said, adding that the explosion in the number of babies born with that condition was a “cause of great concern.”