Diego Cevallos
MÉRIDA, Mexico, Dec 4 2008 (IPS) – With cutting-edge science, social organisation and a strategy that puts an emphasis on prevention and environmental controls, Cristina Díaz and her team checked the spread of dengue in Cuba, while María Monroy did the same with Chagas disease in Guatemala.
Díaz has a doctorate in biochemistry and won Cuba s National Science Award in January, and Monroy has a PhD in medical entomology and won the National Science Award from Guatemala in 2004.
The Cuban researcher is fighting a disease that affected 866,000 people in Latin America and the Caribbean between January and October alone, while the Guatemalan scientist is working to curb a disease that has infected more than 10 million in the region.
The achievements of Díaz and Monroy, and of several other women involved in the field of ecohealth, were celebrated during the Dec. 1-5 International Ecohealth Forum 2008, which drew some 600 academics, scientists, government experts and activists from dozens of countries around the world to Mérida, on Mexico s southeastern Yucatan peninsula, to discuss the relationship between health and the environment.
In separate interviews with IPS, Díaz and Monroy both pointed out that climate change, which is modifying temperatures and seasonal cycles, and the destruction of ecosystems, are increasing the spread of the two diseases, which are transmitted by insect bites.
DENGUE DROPS TO ZERO
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This year, we have not had any cases of dengue in Cuba, we have it under control. If there are cases, they are all imported (by carriers of the disease visiting from other countries), the Cuban researcher said with obvious pride.
Díaz attributed that success to the multidisciplinary approach that she said was followed in her country, where cases of dengue fever were counted in the thousands in the not-so-distant past.
In fact, it was in Cuba that the first epidemic of the potentially deadly dengue hemorrhagic fever occurred in the Americas, in 1981, with more than 10,000 cases.
The health sector pays the costs of dengue fever, but the causes of the problem are found in the environment, said the expert.
Díaz and her team at the Pedro Kouri Institute of Tropical Medicine in Havana convinced the authorities that it was necessary to incorporate environmental controls and wide social participation in the fight against dengue.
As a result, starting in 2002, areas that served as mosquito breeding grounds were identified, and the authorities, along with local residents, got to work.
The dengue virus is carried by the Aedes aegypti mosquito, which transmits the disease by biting an infected person and then biting someone else.
Although there is neither a cure nor a vaccine for the disease, the symptoms generally abate if the patient follows a regime of complete rest, continued hydration intravenous in severe cases and treatment with acetaminophen. But complete recovery can take up to a month.
Symptoms include a high fever, rash, severe headache, pain behind the eyes, muscle and joint pain, loss of appetite, nausea and vomiting. Most infections result in relatively mild illness, but some cases progress to dengue hemorrhagic fever, which can be fatal.
Prevention efforts involve making sure that water does not accumulate in containers, like discarded tires, flower pots or old oil drums in shady areas close to human dwellings in urban areas, where the mosquitoes thrive because they prefer to lay their eggs in clean water.
According to the Pan-American Health Organisation (PAHO), nearly 866,000 people in the region were infected by dengue fever this year as of late October, and 238 patients died. The countries of South America, with Brazil at the head, were hit hardest.
If the vector appears, it means we have an environmental problem, which has to be attacked, said Díaz.
The multi-disciplinary approach goes beyond the spraying of affected zones, which is not effective on its own, said the researcher.
FEWER FORESTS, MORE CHAGAS
Three weeks ago, Guatemala became the first country in Central America to be declared free of Chagas disease transmission by the WHO (World Health Organisation), said Monroy, the founder of the laboratory of entomology and parasitology at the University of San Carlos School of Science and Pharmacy in Guatemala.
The Swiss-educated scientist said that a decade ago, hundreds of cases of Chagas disease were reported annually in her country. But this year, after several years of work with local communities, we have controlled the problem, using a holistic approach, she said.
There is no cure or vaccine for the often deadly Chagas disease, and in most cases only treatment of symptoms is possible.
The disease is caused by the bite of the reduviid bug, which lives in crevices and gaps in poor rural housing like thatch, mud or adobe huts in a number of Latin American countries.
The bug transmits a protozoan parasite named Trypanosoma cruzi through its faeces, which human victims unwittingly rub into the bite wound left by the bug, or into their eyes, mouth or nose. The parasites thus enter the victim s bloodstream and gradually invade organs of the body, often causing severe damage to the heart, digestive tract or nervous system.
The disease has three stages: acute infection, in which symptoms occur soon after infection; an asymptomatic phase, which can last months or years; and chronic infection.
In the first stage, which only a small minority of patients suffer, symptoms include swelling of the eye on one side of the face, exhaustion, fever, enlarged liver or spleen, swollen lymph glands, a rash, loss of appetite, diarrhea and vomiting.
Symptoms in the chronic stage can appear years or even decades after infection. Health problems include serious, irreversible damage to the heart or intestinal tract.
Monroy said that most reduviid bugs live in the forests, and that when we cut down the forests, the bugs have to go somewhere, and we provide them with ideal conditions. What temperature does the bug like? 23 degrees Celsius, the same temperature I prefer, so they come to our homes where it is warm, slightly damp, and dark, she said.
We provide the conditions that make Chagas disease a public health problem, said the scientific researcher.
Monroy works with health authorities in Guatemala to combat the spread of the disease, with the direct participation of affected communities. Local communities are taught about the disease and its characteristics, and with that information, they adapt their homes to keep the reduviid bug out and to live in harmony with the environment, she said.
Only an integrated approach that leaves aside spraying as the sole method for fighting the disease is effective, said the scientist.
PAHO reports that the socioeconomic impact of Chagas disease in Latin America is extremely high, ranking it behind respiratory infections, diarrhea and HIV/AIDS.
In Guatemala we have curbed the disease; we no longer have a significant number of cases, thanks to the integral approach. If this strategy is applied in the rest of the countries, the battle will be won, said Monroy.