The Pan American Health Organization (PAHO) has reiterated its previous recommendation that Caribbean and other international travelers be vaccinated at least 10 days prior to traveling to or visiting areas where yellow fever is circulating.
PAHO said it continues to encourage member states to take all actions necessary to keep travelers well informed of risks and preventive measures, including vaccination.
“Travelers should also take precautions to prevent mosquito bites and should seek immediate medical attention if they fall ill during or after their trip,” PAHO said.
“Confirmed cases of yellow fever in unvaccinated travelers underscore the need for countries to ensure wide dissemination of these recommendations,” it added.
Between January 2016 to January 2018, PAHO said seven countries and territories in the Region of the Americas have reported cases of yellow fever: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Peru and Suriname.
PAHO said Brazil has notified the largest number of yellow fever cases during this period, with cases being recorded in areas where virus circulation had not been observed in several decades, including in the states of São Paulo and Rio de Janeiro.
Sylvatic yellow fever outbreaks occur periodically in wild monkeys and are known as epizootics, PAHO said.
In these epizootics, it said the yellow fever virus is transmitted to monkeys by forest dwelling mosquitoes, such as Haemagogus and Sabethes.
PAHO said humans who are exposed to these mosquitoes can become infected if they are not vaccinated.
In the current outbreak in Brazil, all human cases of yellow fever have been linked to Haemagogus andSabethes mosquitoes, PAHO said.
Additionally, it said these epizootics have been observed in ecosystems near cities and in forest corridors within urban areas.
Urban transmission of yellow fever virus occurs when the virus is spread from human to human by the Aedes aegypti mosquitoes, PAHO said. The last documented outbreak of urban yellow fever in Brazil was recorded in 1942.
PAHO said yellow fever is an acute viral hemorrhagic fever that can result in death.
“It is preventable with a vaccine that is safe, effective and accessible,” PAHO said.