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Jun 13, 2016 05:38 PM


Brazil shows an 87% reduction in the number of Zika cases notified

Data points to a fall in the number of diseases transmitted by the Aedes aegypti, resulting from national actions put in place. Transmission risk at Games time is of 1.8 cases per 1 million people

The risk of transmission of Aedes agepyti mosquito related diseases in Brazil at Games time is minimal. This Friday (10.06), the Minister of Health Ricardo Barros presented data that backs this up at a press conference with foreign correspondents in Rio de Janeiro. The number of Zika virus cases has been falling in the country, having dropped 87% from February to May this year.

The peak in the number of cases registered happened in the third week of February, with 16,059 occurrences having been notified. In the first week of May, the number of cases fell to 2,053. The figures reinforce the result of actions put in place to fight the Aedes aegypti mosquito, as well as showing a different behaviour this year in relation to what is normally expected. In 2016, the drop in the number of cases started before expected, as historically the peak of diseases transmitted by the Aedes aegypti is in April.

"According to a study published by the University of Cambridge, less than 1 case of infection is expected amongst the 500 thousand tourists who will be coming to Brazil for the Olympics. The Zika risk is minimal, particularly because of the period's weather conditions and mobilisation aimed at fighting the mosquito here in Rio de Janeiro", pointed out Minister Ricardo Barros.

He also said that Rio de Janeiro will have reinforcements of 2.5 thousand health professionals. In addition, all athletes under the charge of the Olympic Committee will have repellent made available to them, as well as specific clothing and necessary material. "Like the World Cup and World Youth Day, we're certain that our people's courtesy and the quality in staging mega events are guaranteed for the Olympic Games".
In cities where Olympic and Paralympic events will be held, the numbers behaved similarly to the national figures, with the disease reaching its peak in February and falling expressively in the following months. For example, the municipality of Rio de Janeiro saw the highest number of cases in the third week of February (2,116). In the following weeks, numbers fell, reaching 208 cases notified in May, which represents a 90% reduction.

» See presentation in full, in Portuguese (document in pdf format)


Contrary to the northern hemisphere, Brazil is in the winter period now, when historically and epidemiologically, the number of cases of diseases transmitted by the mosquito drop and reach their lowest figures. The date corresponds to the months of August and September, when the Olympic and Paralympic Games will be held in Brazil.

The Minister of Health Ricardo Barros recalls that during the 2014 World Cup, people were also afraid of visiting the country and catching diseases transmitted by the Aedes aegypti. "During the World Cup three cases were registered in tourists. Statistics show that it is not an endemic period. This happens mainly because in winter it doesn't rain as often, which makes it more difficult for the mosquito to proliferate", he stated.

Rio de Janeiro: 90% fall this year - Zika peak in February, 2,116 cases. First week of May, only 208

» Brazilian researchers support the staging of the Olympic Games in Rio de Janeiro

» Brazil and USA governments together in the fight against the Zika virus


1.8 case per 1 million people

A recent study conducted by scientists of the São Paulo Hospital/São Paulo School of Medicine and scientists from another four countries, published in a University of Cambridge Journal (UK), shows that the risk of tourists contracting the Zika virus at Games time is of 1.8 cases per 1 million people.
In order to establish the probability, researchers analysed the curve of cases per epidemiological week of dengue in the city of Rio de Janeiro. After the analysis, it was possible to calculate a parameter for the presence of the Aedes aegypti at Games time in 2016.

Taking into consideration the 500 thousand foreign tourists expected at the Games, there would be less than one Zika case in the period. "If a million tourists come to Brazil for the Olympics, which is a considerable number, we probably won't have more than five cases of Zika among them. So, it's a very low risk with small repercussion from a public health point of view", pointed out Professor Marcelo Burattini, from the São Paulo Federal University (UNIFESP), one of the study's authors.

For the professor, the Southeast region at Games time practically does not have activity in relation to diseases transmitted by the Aedes aegypti. "Our estimate should be considered as an upper limit, with maximum risk to be reached. The real risk will probably be much lower than that", he stated.

Set of actions

The Ministry of Health, in partnership with the Rio de Janeiro state government and City Hall, put together a series of actions throughout the country to ensure health care during the competition. Seventy-two million reais were invested in the purchase of equipment and paying for the cost of 146 ambulances, which will be on call at Games time. In addition, another R$ 2.8 million have been allocated to the procurement of personal protective equipment (PPE) – like gloves and masks – and antidotes for chemical, biological and radiological emergencies. In addition, 1.7 thousand professionals are being trained to deal with emergencies, like chemical and biological accidents.

Furthermore, 2,500 temporary health professionals are being hired, among doctors, nurses and nursing technicians to reinforce numbers in relation to assistance offered by federal hospitals in Rio. Moreover, 3,500 professionals are at work, like external agents, inspecting and eliminating dengue breeding sites, instructing people and visiting the whole region in the surrounding areas where the Games will be held. The Joint Health Operations Centre (CIOCS) will start operating on 5 July, monitoring risky situations, demand for assistance, epidemiological and health surveillance, as well as coordinating responses vis-à-vis public health emergencies.

» In order to guide visitors with health prevention information, the Ministry of Health has put out the Saúde do Viajante (Traveller's Health) webpage ( in Portuguese, English, Spanish and French.


The Zika virus can be found in 60 countries, including Brazil, whose population represents only 15% of people exposed to the virus. The Ministry of Health has made notification in Zika virus cases compulsory since February this year. However, even before being compulsory in the whole country, some states had adopted notification for all cases where the Zika virus was suspected, like Rio de Janeiro, Bahia, Pernambuco and Rio Grande do Norte. This initiative may show more care in relation to prevention and control matters of the disease.

Source: Ministry of Health