Travellers should take precautionary measures to avoid mosquito bites following the declaration of a national dengue alert in the Philippines on 15th July. 106,630 cases have been recorded from January to June this year. This represents an 85% increase compared to the same period in 2018. The most number of cases have been recorded in Western Visayas, Calabarzon, Central Visayas, northern Mindanao and Soccsksargen.
Meanwhile, similar dengue warnings have been posted by the Brazilian Public Health Department aimed at travellers in Minas Gerais state and its capital city, Belo Horizionte. As of 8th July, at least 438,666 probable cases of dengue and 107 fatalities were reported in multiple municipalities. Governor Romeu Zema had announced a public health emergency in the state on 23rd April. So far, thousands of probable cases of Zika and chikungunya fever have also reported in the state this year. In many other countries, dengue is also imposing a large and rapidly growing burden.
The number of countries subject to infection is increasing and there have been recent reports of cases also occurring in cooler temperate climates.
The infection often displays no symptoms and it’s likely that you won’t even know you’ve had it, especially when it affects children. Alternatively, in some cases it may cause flu-like symptoms, such as fever, severe headache, muscle and joint pain. But, if you get infected a second time, with a different strain of the virus, some people will develop a more severe infection. It can provoke an acute illness with organ failure and uncontrolled bleeding which can cause death. Other tropical viruses, such as Ebola have much higher mortality rates but infect few individuals. In comparison dengue has a low mortality rate, but as it is common, many thousands of patients die each year.
There is now a vaccine for dengue fever. CYD-TDV is the first dengue vaccine to be licensed. It was first licensed in Mexico in December 2015 for use in individuals nine to 45 years of age living in endemic areas, and is now licensed in 20 countries. CYD-TDV is a live vaccine, given as a three-dose series on a zero, six and 12 month schedule. In studies, the vaccine was shown to prevent more than 90% of severe disease and 80% of hospitalisations due to dengue.
It should be noted, however, that the vaccine should not be given to individuals who have not previously been infected by dengue virus, because an increased risk of hospitalisation for dengue and clinically severe dengue has been observed in these individuals during long-term follow-up studies. Previous infection must be confirmed by blood tests before the vaccine is given.
As there is no specific treatment for dengue and the number of infections is increasing, it is still very important to prevent mosquito bites and seek medical attention at the first sign of symptoms.