HEALTH-LATAM: As Dengue Spreads, Brazil Learns from Cuba

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Mar 20 2002 (IPS) - Cuba’s experience in combating dengue fever is Rio de Janeiro state’s newest weapon in its own battle against the disease, whose rapid spread has resulted in an epidemic of uprecedented proportions in Brazil.

Cuba’s secretary of Health Sciences and Technology, Eric Martínez Torres, is in Brazil this week leading numerous meetings, courses and discussions to share the lessons learned in his Caribbean country, which has been successful in fighting off outbreaks of haemorrhagic dengue since the 1980s, sharply limiting the number of fatalities.

Early diagnosis and immediate medical attention can prevent people from dying of the haemorrhagic strain of the disease, says Martínez Torres. The population’s lack of information about dengue could be a negative factor, as the ill often postpone seeking medical attention.

In the city of Rio de Janeiro, 49,149 cases of dengue had been reported from Jan 1 to Mar 19, and 435 of those involved the haemorrhagic strain. The death toll so far this year is 29, but could rise with the confirmation of the cause of death of other victims.

Haemorrhagic dengue is fatal in more than 20 percent of cases if the infected individual does not receive immediate and appropriate medical treatment. So far, there is no vaccine to prevent infection with any of the four known strains of dengue.

The official figures do not reflect the reality of the epidemic, acknowledge the health authorities, because a large portion of the cases are never reported. Conservative estimates indicate that there are four more ill people for every case reported.

Absenteeism in the business sector attributed to dengue, according to the Rio de Janeiro Commerce Association, suggests that 10 percent of employees have been infected.

If the same percentage is applied to the general population of the city – which numbers six million – there could be 600,000 people with dengue.

The true magnitude of the epidemic became clear last month, when several actors on Brazil’s most popular TV soap opera, the Globo network’s “The Clone”, fell ill with dengue, complicating production of the show.

The health authorities are taking advantage of the notoriety of actors Stenio García and Reginaldo Farias, and others, to foment their information and mobilisation campaigns against the mosquito- transmitted disease.

The intensity of the outbreak is attributed to the spread of the dengue virus Type 3, whose presence in Brazil was first detected in December 2000, and to the dismantling of efforts last year to eradicate the mosquito that transmits the disease, the Aedes aegypti, which is also the vector for yellow fever.

The arrival of a new strain of dengue always causes outbreaks because the population has not developed natural immunity against it, say health experts. The same phenomenon occurred in Brazil in 1991, when dengue Type 2 appeared and also caused a major epidemic.

Once an individual is infected with dengue, he or she develops immunity to that specific strain of the disease.

There are four known types of dengue virus. Brazilian researchers fear that the only one not yet present in their country, Type 4, will arrive within the next few years, causing a new epidemic. It has already been reported in neighbouring countries Colombia and Venezuela, and the current flow of travel throughout the region favours its international spread.

Cuba’s Martínez Torres, who is also a consultant to the Pan- American Health Organisation (PAHO), maintains that the risk of a Type 4 epidemic is not as immediate or as serious as the Brazilians fear because the propagation of that virus is slower than the other strains.

Two weeks ago, another Cuban expert – biologist Grisel Montero – visited Rio de Janeiro to share her knowledge about fighting the spread of tropical diseases. She has worked for 30 years to develop methods to combat the mosquitoes that spread dengue, yellow fever and malaria.

Montero, on the board of Labiofam, a government-run Cuban pharmaceutical firm, recommended year-round prevention efforts to prevent the Aedes aegypti from laying eggs, which can survive longer than a year, turning into larva, and then mosquitoes, with the next rainfall.

The biologist also explained to the Brazilian authorities how to use “bio-larvicides”, in this case worms that attack the Aedes aegypti larvae, destroying them before they can grow into adult mosquitoes.

It is a weapon against dengue, developed in Cuba, that is already being implemented in Nueva Iguaçu and Niteroi, two cities of the Rio de Janeiro metropolitan region that have been hit hard by the epidemic.

The dengue-carrying mosquito has developed resistance to chemical poisons, making biological control of the insect a necessary alternative, said Montero.

Niteroi is making use of several years of Cuban experience in public health, like the family health programme, which provides medical assistance in the neighbourhoods themselves.

Such family health programmes are important for containing outbreaks of dengue, said Montero and Martínez Torres.

Two-thirds of Brazil’s municipalities have family doctors or health agents, but they are still relatively scarce in the big cities, just where they are needed to play a decisive role in an emergency like Rio de Janeiro is now facing.

This year, dengue outbreaks are particularly strong in Venezuela, Brazil, Cuba, and several Central American and Caribbean countries.

According to PAHO, dengue was considered a public health problem in Asia, but not in Latin America, until 1981, when Cuba was the scene of the region’s first serious epidemic.

The Aedes aegypti can lay eggs and develop in any receptacle holding clean water, and likes the dark, damp places often found in patios and gardens, making it essential for the community to participate in control and eradication efforts.