Dengue is a flavivirus infection transmitted by the bites of female mosquitoes, mainly of the species Aedes aegypti and Aedes albopictus, which are daytime biters. It is only the female mosquito that feeds off blood to provide protein for the eggs;the males feed off plant nectar.
From its origins in south-east Asia, it has spread to many parts of the tropical and sub-tropical world. Aedes mosqitoes are capable of breeding in small quantities of water, such as accumulated rainwater in oil drums and old tyres, as a consequence of which,
dengue often occurs in urban areas.
What are the main symptoms?
The incubation period is usually between two and five days, but may occasionally be longer. This is followed by fever, which may abate after a day or two, only to rise again. This is known as saddleback fever.
Common symptoms are severe arthralgia and myalgia, giving rise to the name breakbone fever, and headache.
Up to 50% of patients develop a maculopapular rash and there may be widespread lymphadenopathy. Recovery may be accompanied by prolonged fatigue and/or depression.
About 2% of patients may develop severe complications
of dengue such as haemorrhagic fever (DHF) or dengue shock
Warning signs for the rare dengue haemorrhagic fever include:
tiny bloods spots or large patches of blood under your skin, bleeding from the gums or nose, persistent vomiting and severe abdominal pain, vomiting blood or black, tarry stools. If you have any of these symptoms, you must seek immediate medical assistance.
Can it be diagnosed by blood test?
Dengue fever can be diagnosed by isolating the virus in the blood during first five days. Also, on examining the blood there can be low white cell count and platelets and a raised alanine amino transferase (a liver enzyme) but this is not specific to Dengue Fever.
IgM antibodies may persist in the blood for two to three months
and a positive test may indicate recent or previous dengue
infection. If a traveller has had no previous exposure to dengue, a positive test is likely to be due to recent infection, but there is also cross-reactivity with other flaviviruses,
Is there a vaccine?
There is no vaccine
How can Dengue Fever be prevented?
It is a viral infection transmitted by mosquitos that bite in the day. It is important to wear clothing that covers as much of the skin as possible and use effective insect repellents such as diethyltoluamide (DEET) from dawn until dusk (in contrast to malaria prevention throughout the night from dusk until dawn)
How can it be treated?
There is no specific treatment for dengue. In most people symptoms can be managed by taking paracetamol (you should avoid aspirin, ibuprofen or other similar drugs), drinking plenty of fluids and resting.
Most people will recover within one to two weeks.
Before travelling it is advisable to attend a travel centre to obtain appropriate immunisations and advice.
Most immunisations can be given by our practise nurse or at one of the local travel clinics
Travel advice for Brazil
Having said this I had an amazing trip to Brazil several years ago to see my daughter who was studying there and absolutely loved Rio de Janeira, swimming on Copacabana beach, sky-diving on to the beach, dancing Salsa and even visited a Favela under escort. Then going on to explore the incredible Amazon river and Amazonian jungle and fortunately remained very well.