10 facts about dengue fever in Brazil

February 11, 2008 | By More

1. Dengue fever is one of the biggest threats to the health of those living in Brazil and of those visiting the country as well.

Dengue hemorrhagic fever can cause death.

2. Dengue fever is spread throughout most of Brazil.

Contrary to what happens with yellow fever, dengue is present both in rural and urban areas. In many places it occurs in the form of epidemics. From January to November 2007 there were 536,519 cases of dengue fever in Brazil. In the entire 2007, there were 1,541 cases of dengue hemorrhagic fever, with 158 deaths. The fight against dengue fever is hindered by precarious hygiene and sanitation standards in most of the country, the insufficient resources made available by the authorities at all levels, and the attitude of part of the population. According to a recent poll, 91% of the population know what needs to be done to erradicate the mosquito than transmits dengue; however, 55% do nothing about it as their neighbours do nothing either.

Google has an online tool that tracks the occurrence of dengue fever cases in Brazil. It can be checked at Dengue trends: Brazil.

3. Cases of dengue fever increase during the rainy season.

The mosquito that transmits dengue fever becomes active with rain and high temperatures. 86% of the cases registered in 2007 occurred between January and May.

4. So far, there is no vaccine against dengue fever.

Primary prevention of dengue fever consists on avoid being bitten by the mosquito that transmits the disease. Cover your exposed skin and your clothes with repellent.

5. Dengue is transmitted through the bite of the Aedes Agypti mosquito.

The fight against dengue is synonym whth the fight against the mosquito. The adult mosquito is middle-sized, dark with white markings on the sides and the upper part of the thorax. It has white rings on its legs. It is found on houses and their vicinities. It needs clean water to deposit its eggs.

6. Dengue fever is not transmitted between humans.

7. There are four serotypes of dengue fever: 1, 2, 3, 4. Type 4 is the only one not found in Brazil.

Update: type 4 has finally made it to Brazil.

8. Two forms of dengue fever are found in Brazil: classic dengue fever and dengue hemorrhagic fever.

On average, symptom manifest between 5 and 6 days after the infection.

The main symptoms of classic dengue fever are high fever (39° to 40°C); severe headache; rashes (bright red on the lower limbs and the chest); muscle and joint pains; nausea and vomiting.

Initially, the symptoms of dengue hemorrhagic fever are the same as those of classic dengue. After the third or fourth day, hemorrhages appear. It the disease is not treated inmmediately, it can lead to the death of the patient.

If symptoms appears, immediate medical care is need – do go to a hospital or health centre.

9. There is no specific treatment for classic dengue fever.
Aspirins should be avoided as they may favour the appearance of hemorrhages. It is important that the patient prevents dehydration through increased oral fluid intake.

Dengue hemorrhagic fever should be trated in hospital.

10. Dengue fever can be caught more than once (although it will never be the same type). Those who have contracted dengue fever in the past should be extra careful as dengue hemorrhagic fever seems to develop almost exclusively on patients that had had classic dengue fever before.


Combata a Dengue. Website of the Brazilian Ministry of Health, in Portuguese only. Given the size of the problem and the fact that dengue fever does not discriminate between residents and visitors, one would have expected a more proactive attitude from Brazilian authorities when it came to informing tourists about the risks of dengue fever. I haven’t found any mention of dengue fever on the Brazil Tourism Portal, also belonging to the Brazilian government.

One wonders what are the reasons behind this silence and reaches the conclusion that the authorities want to avoid at all costs associating yet another negative issue to the image of a country already blemished by violence, precarious infrastructures and lack of tourist information. If a blogger with no financial support and the collaboration of a doctor can write a entry like the one you are reading now, why shouldn’t a government be able to do something similar?

The U.S. government’s CDC Dengue Fever Fact Sheet can be consulted for further information in English.

This entry has been entirely written with the medical supervision of dr. Gustavo R. Bonzón, to whom we are grateful for this co-operation. Any mistakes contained in the text are the sole responsibility of the blog.

dengue fever alert: state of Bahia (2009)
Dengue fever epidemic in Rio (2008)
Dengue fever in Natal (2008)

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Category: health

Comments (34)

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  1. Rafael says:

    People can travel to Brazil without being afraid of dengue.

  2. Tony says:

    Hi Rafael. I agree with you, you shouldn’t approach your holiday destination with fear unless you want to put in jeopardy the always-important enjoyment factor.

    However, that doesn’t mean you should play down the risks of contracting dengue fever, which are very real. Only recently a couple of Argentinian readers of the blog reported how they had contracted dengue fever while in Ubatuba last year. The symptoms only manifested back in Buenos Aires. One of them stayed 10 days in hospital, in a very serious condition – thankfully she recovered ok.

    Information is the name of the game.

  3. wally says:

    sono appena tornata dal brasile dopo 23 giorni di soggiorno e dopo 4 giorni dal rientro sono stata ricoverata per dengue, considerate che avevo fatto tutta la profilassi preventiva anche se per il dengue non esiste niente, ho sempre usato ddt in camera, zanzariere, autan, abiti chiari e avevo passato tutti gli abiti, materassi e tende con permertina, per me il problema sono le piscine.

  4. Tony says:

    Wally, you forgot to mention where in Brazil you spent your holidays.

    When swimming pools are properly treated against the mosquito, there is no risk whatsoever. The problem are pools belonging to houses and mansions that are left closed by their owners during long periods of time.

  5. Robyn says:

    We are supposed to go to Rio at the end of April to visit family. However, I think planning our trip this time of year was very bad planning and I may pull the plug on it. I have two small children and I am pregnant. We are planning to go to the mountains in Rio to a nice hotel and stay with family for 5 days, then hang out in Rio (staying at my father in laws house in Jardim Botanico) for a few days. Having a week of fun doesn’t seem worth it for the amount of worry and the amount of deet entering my system at this time.

  6. Tony says:

    Robyn, cancel the trip. The risks involved are too high. The crisis in Rio is not improving and will not do so until the beginning of winter (summer in the northern hemisphere). Thousands of new cases are being recorded every week.

  7. Aaquila says:

    I was planning a trip to Brazil in August, but recently one of my friends is threatening to drop out due to dengue fever. From the u.s. embassy website it seems like cases decrease in the winter, but i’m wondering, would contracting the disease still be a substantial risk in August?

  8. Tony says:

    Hi Aaquila, you can tell your friend that, as stated on point 3 of this entry, the vast majority of dengue cases occur during the rainy season. By the beginning of June the situation should be back to normal and the risk should be minimal in August. Look at the statistics for last year, 87% of the cases were recorded between January and May.

  9. stephen downey says:

    im going to rio mid june with 2 mates staying in cococabannashould i reconsider ???? steve

  10. Tony says:

    Hi Stephen, it’s a tough call, things should have improved quite a bit in a couple of months time, and Copacabana is not at the center of the epidemic (worst hit areas are in the west of the city) so I guess you could probably go ahead with your trip – be extra vigilant, though, and bring plenty of repellent with you.

  11. tony says:

    How is the situation now, at the end of june?

  12. Priscy says:

    My dad leaves in Rio and he told me that because of the cold weather has arrived now, things have gotten much better since March. He told me that people should be fine when travelling to Brazil now. As Tony mentioned earlier, the Dengue season always happens during the summer months down there, from December to April. You should be fine if you’re traveling outside the Dengue season.
    As a matter of fact, I’ll be flying down there with my husband in August and we’ll be staying there for 2 weeks. We’ll bring mosquito repellent just in case. Hope this information helps.

  13. Tony says:

    Tony, Priscy is absolutely right, things are much better now and more likely than not we will hear about dengue fever again only at the end of the year with the arrival of the first summer rains.

  14. LL says:

    What is the risk of dengue in the amazon during November and December?

  15. Tony says:

    Should be low, the first cases of the dengue season would usually be reported during that time, but the epidemic usually develops in January/February.

  16. Aggie says:


    Do you have any information about the status for this year (Feb. 2009). We have a trip planned for Feb 7-20. In Rio we’re staying in Copacobana Beach. Planning on using plenty of repallant all the time.


  17. Tony says:

    Aggie, dengue hasn’t made the headlines… yet. As soon as new information emerges I’ll post it in the blog.

  18. Gil says:

    I was reading in O Globo, the Rio paper, the story of dengue fever deaths in Bahia. According to the report, this year’s epidemic has reached 36,000, with 29 confirmed deaths and another 36 suspected.
    I’ve a conference in mid-May in Bahia, and I think that this is a concern. What can I do to minimize my risks? I’d like to pass any information on to colleagues who are also attending.

  19. Tony says:

    Gil, unfortunately dengue fever is fact of life in most of Brazil. I reported recently on the Bahia outbreak (dengue fever alert: state of Bahia) and althought the situation is serious it doesn’t reach the proportions of Rio’s dengue epidemic last year, when the number of cases were counted in hundreds of thousands.

    The situation is not particularly critical in Salvador (there have been dengue cases there, but that is the case for most Brazilian capital cities). Worst affected are Ilhéus and Porto Seguro. I would not cancel any trip because of the situation in Salvador but I would be aware of what the dengue fever symptoms are. There is little you can do. If you are attending a conference you are likely to be on an air-conditioned environment for most of the day, where there is no risk. Outside that environment, apply insect repellent. Have a safe trip!

  20. Andrea says:

    We are travelling from Chile to Porto Seguro with a group of 28 teenagers in the middle of July, I am getting really concerned about this dengue fever, because I’ll be their chaperone. They are asking me about the Dengue and I don’t know what to tell them….what’s your opinion?…please tell me, because I’m starting to bea nerve wreck, besides, we have to deal with swine flu prevention!!!!

  21. Tony says:

    Andrea, very difficult to hand out advice beyond what’s been said here. The dengue outbreak in Porto Seguro this year was quite serious, but if it’s of any comfort, in July it should be clearly on the decline. Do find out more as soon as you arrive in your hotel, get them to tell you the specifics of dengue fever in the area where the hotel is found. Have there been any cases?

    Dengue is much more of an issue than swine flu. A hundred cases of the flu in Brazil versus hundreds of thousands of cases of dengue fever.

  22. Andrea says:

    thanks a lot, I’ll contact the hotel right away!

  23. Maria says:

    i m planning to travel to Brazil in two weeks (mid of July). I already hava had dengue before and I m wondering if july is already cold enough (?) for going there without it being too risky.. The south shoulg be fine, right!? what about the north then?

  24. Tony says:

    Maria, it will be cold in the south and south east states, but dengue still remains a possibility in Bahia and further up north. Where about are you planning to go. As you must be aware, you need to take special care as those who have had dengue fever once are can develop haemorragic dengue if they contract the disease a second time. All the best.

  25. Sérgio says:


    I was planning on visiting Rio, Salvador, Chapada Diamantina and Praia do Forte in August, and researching about swine flu I´ve dicovered the Dengue problem. We travel with our 2 (almost 3) year old daughter and I´m concerned now. Is dengue still a big problem in Bahia in August?


  26. Tony says:

    Sérgio, the outbreak of dengue fever was particularly severe this year in Salvador (last year it was Rio). With the arrival of lower temperatures the number of cases diminishes. That seems to be the case in Salvador (you don’t need to worry about Praia do Forte or de Chapada Diamantina). There are no absolute guarantees, as there are cases almost all-year round, but the worst of the 2009 epidemic seems to be over. If it’s of any comfort, I went to Salvador in the midst of the outbreak.

  27. Sérgio says:

    Thank you Tony. We´ll have to use plenty of repellent in Salvador then, but it seems there´s no reason to cancel…

  28. Tony says:

    Sérgio, I think that’s the idea, don’t cancel the trip but take the necessary precautions while in Salvador. Have a nice trip!

  29. Klas says:

    Hello Tony. Nice website.
    What is your recommendation for pregnant women for visits to Rio and surronding islands in early November? Thanks, klas

  30. Tony says:

    Klas, I’m no health professional, I can’t give recommendations. I can only reproduce statistics and give you a general idea of what the situation in the country is. The number of cases is decreasing and as the warmer weather arrives chances are they will fall even more. November should see very few cases of flu in Rio, a state which, in any case, hasn’t suffered as much as other southern states. The best thing is to keep an eye on the news and see the way the epidemic is evolving. All the best.

  31. Klas says:

    Sorry I meant specificly for dengue fever. What I understand peak period is Jan-Apr. Thanks, klas

  32. Tony says:

    Klas, my apologies, I get so many questions about influenza A these days… This year’s dengue epidemic was milder than last year’s. Hard to tell how the epidemic will come in 2010. But what interests you the most, in November the number of cases is usually negligible as the rainy season is only about to start. The worst of the dengue epidemic usually happens in February and March.

  33. Bernie says:

    We will be cruising from Manaus to the mouth of the Amazon in mid-January 2010. We do have yellow fever immunizations. What is the status there of dengue fever and malaria? Thanks.

  34. Tony says:

    Bernie, I’m just back from Manaus, I did not take any malaria pills as it was the dry season (no mosquitoes around). But the situation changes when the rain starts. I would seek specific advice from the organizers of the trip, as the Amazon is a vast region and advice that is good for Manaus might not be so for Santarém or Belém (and vice-versa). As for dengue fever, it is not so much an issue as it is malaria.