HEALTH-BRAZIL: Dengue, a 21st Century Plague

By Mario Osava Reprint | | Print |

Mario Osava

RIO DE JANEIRO, Feb 22 2002 (IPS) - The residents of this Brazilian city are on edge due to the current dengue epidemic, a disease that is expanding worldwide and is seen as the high price of rapid and unregulated urbanisation in developing countries.

“Dengue has come to stay,” and the propagation and seriousness of this disease have been on the rise over several decades, says Celso Ramos Filho, professor at the Federal University of Rio de Janeiro and preventive medicine advocate.

The disease-transmitting mosquito, the Aedes aegypti, which 30 years ago was found only in the Caribbean region and in Guyana, Suriname and Venezuela, now is present throughout Latin America, with the exception of Chile, Uruguay and southern Argentina, which are protected by their colder climates, said Ramos.

In 1970, just 10 countries had recorded cases of the haemorrhagic strain of the disease, but today there are several dozen, he said. Haemorrhagic dengue is fatal in more than 20 percent of cases if the patient does not receive adequate medical treatment. So far, there is no vaccine to prevent infection.

The World Health Organisation (WHO) calculates that this modern plague threatens 2.5 billion people, or 40 percent of the global population. Dengue is a purely urban in nature, unlike other diseases spread by mosquitoes, like malaria and yellow fever.

Fifty to 100 million people contract dengue each year, and half a million of these cases are haemorrhagic, with mortality reaching five percent. The incidence among children is high in Southeast Asia.

For now, it is a plague limited to the planet’s tropical and subtropical regions, that is, poor countries, with the exception of some, like Australia. But the Aedes aegypti can already be found in North Africa and is beginning to make its way into Southern Europe, said Ramos.

Dengue outbreaks are inevitable wherever the mosquito has a massive presence. In Brazil, cases were first reported in Boa Vista, near the Venezuelan border. Rio de Janeiro suffered its first epidemic in the summer of 1986-1987, and others followed in the 1990s.

The current epidemic is the worst so far, due to the rapid spread of the disease, including its most acute strains. In Rio de Janeiro state, which is home to 14.4 million people, there were 33,671 dengue cases reported from Jan 1 to Feb 21. Of the total, 577 were haemorrhagic, and 14 people have died.

But the reality is thought to be even worse, as experts believe that most private clinics do not always report dengue cases to the health authorities, and there are many ill who do not seek professional treatment.

There is a great deal of nervousness among the state’s population and in neighbouring regions, due to the rapid spread of the disease. The average number of cases diagnosed daily this week was 1,600, twice that of last week.

Hospitals and clinics are overflowing with patients, and the Health Ministry has requested 2,000 army and navy troops, as well as specialists from other states, to join the fight to eliminate the mosquito in Rio de Janeiro.

Fear of becoming “the next victim” is widespread, commented María do Carmo Brito, a public official from a neighbourhood where there is a high incidence of dengue and of the Aedes aegypti mosquito. Signs of mosquito bites on her arms and legs have her under constant stress, she said.

“Because the symptoms take three to 15 days to appear, I expect to fall sick at any moment,” said Brito, adding that she most fears contracting haemorrhagic dengue, because she already had a case of the classic strain of the disease, and is therefore immune to that serotype.

Dengue is not as terrible as malaria or HIV/AIDS in terms of mortality rates, but it is still a very serious disease, said health expert Ramos.

Individuals infected with dengue can suffer acute pain and high fever for one to two weeks, and those with haemorrhagic dengue require immediate hospitalisation.

“Economic losses are high,” said Ramos, due to the work days lost and because the epidemic is scaring off the usual wave of tourists this Southern Hemisphere summer, the worst season for dengue.

It is impossible to completely eradicate the mosquito and the four strains of the dengue virus, three of which are already present in Brazil, he added.

The Aedes aegypti finds a good home in the large cities of the developing world, where poor sanitation, garbage dumps and shanty homes favour the insect’s proliferation in standing water.

There is little hope for developing a vaccine for the disease within the decade, meaning that people will have to find ways to live with the threat of epidemics and to prevent outbreaks like the one occurring in Rio de Janeiro and other Brazilian cities, said the expert.

Measures to fight the spread of dengue include raising public awareness to eliminate standing water, which means getting rid of discarded plastic containers and used tyres, and to improve sanitation, though this is difficult in cash-strapped developing countries, said Ramos.