In January of this year, several monkeys in a forested area of Trinidad were found to have died from yellow fever. The affected districts were Mayaro (southern Trinidad) and Nariva (south-eastern).
As yellow fever is transmitted between monkeys (and also between monkeys and humans) by mosquitoes, local authorities carried out an extensive public education campaign and intensified its efforts to protect the local population through vaccination.
The last outbreak of yellow fever in the monkey population of Trinidad was in 1995, and amongst humans it was even earlier, in 1975.
The World Health Organisation recommends that travellers to Trinidad and Tobago receive the yellow fever vaccination. This applies to many other countries in the region, so contact Travelvax to find out the requirements for your particular itinerary.
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