HEALTH-BRAZIL: Dengue Spiralling Out of Control

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Feb 1 2002 (IPS) - The dengue epidemic is spiralling out of control in Brazil, where the disease has been reported in two-thirds of the country’s 5,500 municipalities, and the most deadly strain, hemorrhagic dengue fever, is claiming a growing number of victims.

The situation is especially alarming in Rio de Janeiro, where five deaths were confirmed up to Wednesday among the 4,345 documented cases of dengue, 83 of which were caused by the hemorrhagic strain of the disease.

Authorities have also expressed concern with respect to the huge inflow of tourists to Rio de Janeiro, drawn by the southern hemisphere summer and by the preparations for carnival – celebrated Feb 10-12 – which could lead to an increase in cases.

The spread of dengue was “both predictable and avoidable,” because it is no mystery that the disease is transmitted by the Aedes aegypti mosquito, and that the mosquito breeds in stagnant water, Rivaldo Venancio da Cunha, a doctor who specialises in infectious diseases, told IPS.

Of the total 390,701 cases of dengue documented in Brazil last year – 70 percent of them between February and May – 676 involved hemorrhagic dengue, and 28 ended in death, according to the Health Ministry’s National Health Foundation.

A rise in the number of cases last March indicated that the epidemic would be worse this summer, said Sergio Arouca, a former secretary of health in the city of Rio de Janeiro.

The current situation makes it clear that “dengue is here to stay,” and that it will take at least 30 years to eradicate the disease, said Cunha, who told his students at the Federal University of Mato Grosso do Sul, in western Brazil, that they would not have to worry about becoming unemployed if they specialised in that disease.

The Health Ministry stepped up its efforts to combat the Aedes Aegypti mosquito with a massive campaign that involved sending out a large number of vehicles and agents to spray insecticide in cities where cases have been reported.

However, Cunha said the actions being taken are “ineffective” in curbing the epidemic.

The network of laboratories allowing rapid diagnosis, follow-up of the types of dengue virus and research into the disease must be expanded, and the system must be decentralised, to enable local authorities to act more swiftly, he said.

Dengue first appeared in 1779 and 1780 in various parts of Africa, Asia and the Americas. In Latin America, the disease has shown up in tropical zones, and is now spreading in subtropical areas.

The first signs of the disease are flu-like symptoms – fever, intense headache, and joint and muscle pain. It is not transmitted from person to person, but through the Aedes Aegypti mosquito, which originally came from east Africa.

Types 1 and 2 constitute the so-called classic dengue. They cause high fever, headache, and pain in the joints and the eyes, but are considered the least dangerous strains. Type 3, hemorrhagic dengue, and type 4 – which has been detected in Venezuela, Ecuador and Peru – are the deadliest.

There is no vaccine or cure for dengue, which produces a loss of platelets, so health authorities are focusing their efforts on preventing the Aedes aegypti from breeding, with informational campaigns urging people not to leave containers, old tires or anything that can collect water laying around.

Hemorrhagic dengue is a growing reality in Brazil, “but there is no justification for the death of patients due to tardy diagnosis of a disease that is well-known around the world, and which has already been present in this country (in its deadliest form) for 10 years,” Cunha maintained.

The first cases of hemorrhagic dengue were registered in Brazil during a serious 1990-91 epidemic in the city of Niteroi, near Rio de Janeiro, recalled the researcher, whose doctoral studies focused on dengue.

Untreated hemorrhagic dengue is frequently fatal. There is no specific treatment, but intravenous fluids and oxygen therapy are often needed to keep the patient from going into shock, which is the cause of most of the deaths.

The bleeding, in small pinpoints on the skin, or just below the skin, tends to occur when the patient suffers a relapse. A major rise in cases is feared, since type 3 dengue – to which those who have suffered types 1 or 2 are not immune – was detected in Rio de Janeiro two years ago.

But in Brazil, the disease has not followed the same pattern detected in Cuba and southeast Asia, said Cunha. For example, children under 15 are not the main victims here, as expected, and adults have been involved in 95 percent of the cases of hemorrhagic dengue.

Cunha said the people most likely to be affected by that strain of the disease in Brazil are those with other health problems, like high blood pressure, diabetes, asthma or rheumatism, and those who take medicine that alters the coagulation of blood, such as acetylsalicylic acid (aspirin).

The epidemic has also had an impact on the economy, especially on the tourism industry, due to a drop in the number of visitors to areas heavily affected by dengue, and on other sectors due to the numerous lost workdays caused by the disease.

The city of Fortaleza in northeastern Brazil was hit hard by the consequences of the epidemic in 1994, “when many foreign tourists cancelled their travel plans,” Cunha pointed out.

Dengue is a serious global public health problem. In Latin America, nearly all countries are facing out-breaks like those experienced by Brazil, with the exception of areas far to the south, where colder winters kill the mosquitos that transmit the disease, said the expert.

The cross-border spread of the disease is inevitable, due to the steady rise in international travel.

The type 3 virus, found in 15 countries, including neighbours of Brazil like Ecuador, Peru and Venezuela, came into this country over the border. And the type 4 virus has already been found in those countries, according to the National Health Foundation.

Brazil, a country of 162 million, accounted for 63 percent of the cases documented in Latin America in 2000, with 375,044 cases. However, the incidence of the disease was higher, in proportional terms, in countries like Costa Rica, Ecuador, Honduras, Paraguay and Surinam.

Besides dengue, the Aedes aegypti mosquito is spreading yellow fever in Brazil, which could stage a return to urban areas, from which it was eradicated 60 years ago, although it remained endemic in the Amazon jungle region and surrounding areas.

A number of cases of yellow fever, several of them fatal, were reported last year in cities near Belo Horizonte, the capital of the central state of Minas Gerais.

Within the next few days, the Health Ministry will launch a campaign to inform the population of the dangers of travelling to at-risk areas.

But unlike dengue, there is a vaccine against yellow fever, which provides immunity for 10 years.