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Epidemiology

The Amazon against malaria

Tests in the laboratory corroborate the biological action of plants from the forest used by the native populations

ARI HIDALGO/UFAMCaapeba: roots against malariaARI HIDALGO/UFAM

There were over 350 days of expeditions over seven municipalities of the state of Amazonas in search of popular knowledge about treatments for malaria. Lin Chau Ming, from the School of Agronomic Sciences of the São Paulo State Universities (Unesp), in Botucatu, and Ari de Freitas Hidalgo, from the Faculty of Agrarian Sciences of the Federal University of Amazonas (Ufam), proposed to survey the repertoire of leaves, roots, creepers, and the bark of plants used to prevent or alleviate the symptoms of malaria amongst the region of Manaus and the channel of the Solimões River. Of the 71 people interviewed, between 34 and 83 years old, only eight had never caught malaria, while 32 had had it at least three times – two men claimed to have had malaria over 20 times. Almost all, in short, were recurrent victims of the illness, used to looking in the forest for substances to fight its symptoms.

Ming and Hidalgo gathered information on the use of the 126 species described as effective, not only against malaria, but also against its consequences, such as problems with the liver and kidneys or anemia. Of the species indicated, 82 referred specifically to malaria or to fever, the main symptom, and another 91 to the liver, the organ most affected.In a preliminary test, the researchers assessed the action of the plant extracts on larvae of Artemia franciscana, a microcrustacean used to detect the bioactive potential of substances, due to its capacity for surviving metabolic paralysis. Only 22 of the 126 plants showed no effect on the larvae of the Artemia.

In some cases, as in that of the extracts of sacaca (Croton cajucara), camapu or mullaca (Physalis angulata) and of caapeba (Potomorphe peltata), 100% of the larvae died. At other times, the result was less noteworthy, which does not go so far as to disqualify the popular knowledge. On example is the saracura-mirá creeper (Ampelozizyphus amazonicus), the raw material of a foaming medicinal drink known as Indian beer.

In the tests, the mortality of the crustacean ranged between 61% and 70%. But there are indications that this plant may even have a role in the prevention of malaria, as the riverside dwellers say. Researchers from the Federal University of Minas Gerais (UFMG) and from the Oswaldo Cruz Foundation (Fiocruz) showed that the extract of saracura-mirá blocks the cycle of malaria in the organism, preventing the protozoon that causes the disease from reaching the bloodstream and sparking off the attacks of fever.

Other researchers had described plants used against malaria, but had limited themselves to drawing up lists of them. Maria das Graças Brandão, from UFMG, went a little further: she did surveys in two states, Rondônia and Pará, and tests with Plasmodium falciparum, the protozoon that causes malaria. But this is the first time that the efficiency of extracts of plants used in Amazonas is assessed – and 22 of the 127 species had not been mentioned before in any other research. In the next stage, the extracts will be submitted to more accurate tests, with standardized strains of Plasmodium falciparum, cultivated at the Amazonas Tropical Medicine Institute.

The intention is to use popular knowledge as a short cut to new medicines. Tools like these belong to the sphere of ethnobotany, which is the study of the use of plants by human groups. “Malaria was introduced in the Amazon over 200 years ago, and both the Indians and the caboclos (persons of mixed Brazilian Indian and European or African ancestry) had to develop their own means for treatment”, Ming says. “This apprenticeship is the starting point for researching for new drugs.”

The strategies available for combating the disease have reached a limit. The mosquitoes that transmit the disease, from the Anopheles genus, have been creating resistance to insecticides, and chloroquine, the most traditional remedy for malaria, is no longer effective against some strains of Plasmodium falciparum. There is another option, the Asian herb Artemisia annua, from which artemisinin is produced, but its production cost is still high. The Indians and the riverside populations have been suffering from malaria since the 18th century, when the disease was brought from Africa with the colonizers. Taking this experience into account may lead to new strategies for fighting it.

Risks
Malaria is a debilitating disease, which causes fevers and anemia, and makes the organism susceptible to other illnesses. It reduces output at work, calls for the victims to travel to places that have the conditions for making a diagnosis, and in some cases can be lethal, above all in undernourished individuals. “In the case of malaria in pregnancy”, Ming comments, “malformation of the fetus may occur, delay in intra-uterine development, or even miscarriages, besides permanent sequelas in the child.”

In Brazil, 99% of the cases of malaria occur in the northern region, where the illness keeps up a challenging resistance: from 11,000 cases in Amazonas in 1985, the figures reached 180,000 in 2000, to fall to 40,000 in the following year. “In 1999, there was the greatest outbreak in Amazonas, with 167,722 cases registered and certainly many thousands not included in the statistics”, Hidalgo says. “This was the moment that I decided to work with more perseverance in the quest for alternatives for minimizing the suffering caused by malaria.”

Between 2001 and 2003, Ming and Hidalgo, in five journeys thatlasted on average two and a half months each, visited three municipalities from the Manaus region (Careiro, Presidente Figueiredo and Rio Preto da Eva) and four in the area of influence of the Solimões River (Atalaia do Norte, Benjamin Constant, Tefé and Coari). In each place, the interviewees were selected with the support of agents from the National Health Foundation (Funasa) and volunteers from the Children’s Ministry.

Although Funasa sponsors periodical campaigns on the importance of combating mosquitoes, a good number of the interviewees still think that malaria is really propagated by water (please see Medicines From the Earth). “Many associate malaria with the beans that fall from a tree called baú-baú and contaminate the water”, Hidalgo says. “In actual fact, there is a coincidence between the tree’s reproductive cycle and the high waters, which flood the land and favor the proliferation of the mosquitoes and, as a consequence, of malaria.” By 2006, Hidalgo and Ming intend to repeat their research in the channel of the Negro River, where Indians show a stronger presence than caboclos.

Medicines from the earth 
For decades, technicians from Funasa have been roaming the Amazoa, doing talks and campaigns to prevent and to eradicate the transmitting mosquito, called carapanã, collecting blood, and distributing medicines. In spite of the intensive work, the use of plants is a frequent practice, particularly as a way of avoiding the side effects of the pills, like dizziness or nausea, sometimes mistaken for the symptoms of the disease itself.

With leaves, roots, or bark of plants like the mountain cabbage palm (Euterpe precatoria), the copal tree (Copaifera sp.) and caapeba (Pothomorphe peltata) malaria is treated, as are the problems it causes, like hepatitis and anemia. But trees used medicinally like the carapanaúba (Aspidosperma sp.) are sometimes uprooted to give way to small plantations.

The fever that comes from the water
Besides researching into plants and their forms of use, Lin Chau Ming and Ari de Freitas Hidalgo gathered statements on how malaria is seen in the Amazon, what causes it, and how to deal with it. “In some municipalities, malaria is considered almost as common as flu”, Ming says. “They live with it like they do with a cold.” It is also called paludism, trembling, or simply fever; the older inhabitants still remember when they called it ague.

“I felt a strong headache, a lot of shivering, and pain in the bones. It gave me such a fit of trembling that I thought I was going to die. I kept putting on sheet after sheet. Then after that I went dizzy, felt very weak. The first time not a lot, but the second time I thought I was going to die.” Maria José Rodrigues, 50 years old, Tefé. “Cold, fever, pain in the bones and in the body. You are rolled up in cloth but the cold doesn’t go away. You get a strong headache, it’s that that kills you, you almost go crazy.” Nazaré Reis, 46 years old, Careiro.

The researchers concluded that the strategy for combating malaria might not be bringing about the effects desired, amongst other reasons, for the conviction of the population that the disease may have more than one cause: at least half of those interviewed do not regard the information given by the technicians about the forms of transmission of the protozoon that causes the disease as entirely true.

“It’s the following: they say it is introduced by the mosquito, but I don’t believe it. It’s more from the water, where the waters meet.” Isaías Gomes, 54 years old, Tefé. “Folks say that it’s the carapanã, but I say it comes from the water. Beans are poison, if you drink water with beans, you get malaria.” Nelsina Vitor, 81 years old, Careiro.”There were some nurses who went through here saying that you get it from the carapanã, but I don’t known if anyone here in the community has got it that way.” Aldair Ramirez, 39 years old, Benjamin Constant.

For the majority of those interviewed (84.5%), if you have malaria or have just had a bout, you should follow a specific diet and avoid some kinds of meat, particularly the fatty ones – known in Amazonia as rheumy –, to prevent the disease from reappearing immediately.”You got malaria, you got your liver hurt, all sensitive, you can’t eat everything you like. There are things that affect the liver a lot, particularly food with plenty of fat. When you’re sick you have to eat light food.” Irondina Machado, 65 years old, Careiro.

“Take tapir meat, just look at it, 15 or 20 days may have gone by without you feeling a thing any more, but eat tapir meat to so how it comes back. It’s very, very rheumy. Ave Maria, I’d be more scared of tapir meat than anything else.” Manoel Pinto, 79 years old, Careiro.

“Pirarucu? Don’t even think of it! It just has to hit your stomach and the thing comes back. It inflames everything, liver, stomach. The blood turns bad, if you get an itch, it all bursts out.” Sandra Amaral, 66 years old, Rio Preto da Eva.”If you eat pirarucu, piranha, it does you no good. It gets worse, has more strength to ill treat a person’s organs. Avoid this stuff and it will start to leave you”. Artur Fortes, 74 years old, Benjamin Constant.

The Project
Ethnobotany of Antimalarial Plants from the Channel of the Solimões River and the Manaus Region (nº 01/01091-2); Modality Regular Line of Research Grants; Coordinator Lin Chau Ming – Unesp; Investment
R$ 31,025.11

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