Dengue in South America
In the spring months of the southern hemisphere there is an increasing interest in taking a cruise around the coastline of the countries of the continent stopping daily to see the wonders of the exotic flora and culture .
At the same time is a need to protect against infection and this year there are concerning reports about the levels of dengue in some of these countries. In 2023 there were 6.5 million reported cases and 7300 deaths. In 2024 the countries with some of the highest reported levels are in Brazil, Colombia, Argentina.
Dengue is a viral disease spread by a daytime feeding mosquito. It is this awareness of the daytime feeding habit that makes in different to other mosquito borne diseases such as malaria. Dengue is further complicated as it has 4 different sub-groups called serotypes. In order to be fully protected against the disease there would be need for the traveller to contract all 4 types as there is no cross-protection between them.
With the increasing levels of dengue in the urban areas a recently licensed vaccine has been made available in the UK for protection against dengue. The UK licence makes this available to all travellers over the age of 4 years, with no upper age limit. With the high levels of reported dengue this makes it a priority vaccine for consideration during activities such as cruising.
Traditionally cruises in this part of the world sail to new destinations overnight and allow passengers to explore the local ports during the day. With dawn and the early morning being of a high-risk time for the feeding female mosquito, the prevention was formally only by using insect repellents applied to the skin. As no vaccine is fully protective then the application of products containing DEET, picaridin or oil of lemon eucalyptus need to be applied. These are the only 3 active ingredients that WHO confirm have evidence to repel insects, other products may claim to have protection but have no evidence to support such claims.
When considering a cruise or land-based activity in South America this autumn the high risk of dengue needs to be assessed with your travel clinic to consider the vaccine and use of the correct insect repellent.
Written by Derek Evans FFTM RCPS(Glasgow), FISTM, FRPharmS, FRGS
Travel Health and Vaccination Lead
