In Check for Years : Malaria: An Old Enemy Rises Again

Tourists thrive on the white beaches of Africa’s eastern coast, cooled by the breeze that sweeps off the Indian Ocean and sustained by a diet of giant prawns.

Mosquitoes thrive here as well, born in the marshy nooks and crannies inland, growing to maturity under a blanket of hot, muggy air and feasting on sleeping people.

Rosemary Henrich wanted to protect herself from the malaria parasite carried by some of those mosquitoes during her four-day holiday at a luxury beach hotel here earlier this year. So she took chloroquine, long considered the world’s primary anti-malarial drug.

But a few weeks after Henrich returned to Nairobi, where she is a nurse at the U.S. Embassy, “I went to open a mayonnaise jar and my muscles hurt so bad I couldn’t open it,” she said. “My bones hurt.” Fever followed. She had malaria.

Travel Agent Stricken

Zebun Akbarali, a Mombasa travel agent, came down with a severe case of malaria about the same time and was in bed for two weeks. Her doctors were surprised. Lifelong exposure to malaria, they thought, should have given her immunity.

In June, a doctor was called to the home of Barbara Allen, then the U.S. consul in Mombasa. She had been ill with a fever for a week. She died of malaria a few weeks later.

Malaria is a perpetual problem for Africa. A 1951 study estimated that 1 million African children die of malaria every year. Today, 35 years later, few experts believe that figure has changed.

But now, visitors to Africa from the developed world, who have no natural immunity, are getting malaria more frequently--and more severely--than before. Strains of malaria able to outwit chloroquine have appeared in East Africa and are moving westward “like a brush fire right across the continent,” said Dr. Wallace Peters, a professor at the London School of Hygiene and Tropical Medicine.

New Research Effort

The renewed malaria threat has spawned a worldwide increase in funding for research. At least five major laboratories, including two in the United States, are trying to develop malaria vaccines using genetic engineering. Dozens of other laboratories, from Switzerland to China, are searching for new compounds to fight disease.

Drug-resistant malaria occurs mostly in rural parts--often jungle--of northern South America, Southeast Asia and East Africa. There is also some risk of malaria--but not the drug-resistant variety--in much of Central America, India, parts of China and west and central Africa. It has been estimated that 300 million people worldwide are afflicted with the ailment each year and that 2 million die from it.

Only a decade ago doctors were so confident of their ability to treat the disease that malaria specialists and even entomologists who studied mosquitoes became endangered species.

Renewed Quinine Use

“Chloroquine was so good. . . . You could give it and if the patient was not better in 24 hours, you knew he didn’t have malaria,” Dr. Philip Rees, director of the African Medical and Research Foundation in Nairobi, said. “Now it could still be malaria, and in 24 hours it will be much worse.”

Rees and other doctors who treat the most severe cases of malaria now routinely use quinine, which is highly effective but 50 times more expensive than chloroquine, more toxic and more difficult to administer. Quinine is the oldest treatment for malaria, a treatment of last resort that has not been used regularly in most parts of the world since World War II.

About one visitor or non-African resident dies of malaria every month in East Africa, doctors here say. They stress that deaths among people with access to medical care are exceptions. And while drug resistance has made malaria more dangerous, it is still a treatable disease, they say.

‘No One Should Die’

“No one should die of malaria anymore,” said Dr. Keith McAdam, of London’s School of Tropical Medicine. “If it is spotted early enough, it can be treated. The trouble is that people come in late.”

A malaria parasite in the blood can multiply 28 times every two days. A patient can be comatose, with cerebral malaria, within a week.

“You can go from a safe situation to a dangerous situation very quickly,” Rees said. “It’s when you sit at home and don’t do anything that you get into trouble.”

Falciparum malaria, which accounts for 90% of cases in Africa, is the most deadly variety and almost always leads to death if untreated. But the disease can be identified, in all but rare cases, by a relatively simple blood test.

Prehistoric Disease

Malaria has been around since prehistoric times. Scientists believe it may have originated in East Africa, the cradle of the human race. The Greek physician Hippocrates--in the 5th Century BC--was the first to describe the symptoms and complications of the disease.

Early doctors noticed that fever, the most common symptom, struck people living near foul-smelling swamps. So they blamed the air, and the disease became known in Italian as mal-aria, “bad air.” Centuries later, in 1897, a British scientist, Ronald Ross, proved that the malaria parasite is carried by mosquitoes.

The disease is a blood parasite transmitted by female anopheles mosquitoes, whose long life span makes them uniquely qualified for the job. Adult female mosquitoes bite a human being every few days, only at night, and use protein from the blood for reproduction. (Male mosquitoes do not bite.)

The disease is spread when the mosquito draws blood from someone infected with the malaria parasite. While the organism does not seem to have ill effects on the mosquito, the insect becomes infectious 10 days after biting the victim. The infectious mosquito then transmits the parasites with its next bite.

Red Cells Invaded

The parasites grow and multiply in the red blood cells. A week or two after the infection, they burst out into the blood stream in large numbers and begin invading other red blood cells. That usually triggers a sudden fever in the victim, signaling the body’s attempts to fight the invasion.

The most severe cases occur when clumps of these infested red blood cells begin to block the blood vessels of internal organs, for reasons not fully understood. When that happens in the brain--cerebral malaria--it often results in a coma.

Malaria deaths are commonly attributed to complications from the attack on the red blood cells and resulting damage to internal organs. A tropical-disease specialist explained it this way: “All the systems of the body just pack up and there is no more life.”

Africans who live in endemic areas usually have a high degree of immunity by the time they become adults. But nature exacts a high price for that immunity: Many children die. A child fortunate enough to avoid a fatal infection builds a protective shield against the parasites by the time he or she reaches adulthood.

Disturbing Trend

About 60% of people in Kenya, for example, have high levels of malaria parasites in their blood, according to recent studies. Technically they have the ailment, but they do not feel ill. Nevertheless, their blood can infect mosquitoes and restart the cycle of malaria transmission.

Doctors have recently noticed a disturbing trend among these usually immune Africans, however. Growing numbers of them are getting severe and sometimes fatal attacks of malaria.

“When natural immunity is not enough, that is a sign that the disease is changing its coat and getting worse,” said a tropical-disease specialist in Nairobi, who asked not to be identified by name for ethical reasons. “I see many more Africans with malaria today than I did three or four years ago.”

The deaths of hundreds of thousands of African children from malaria every year for decades did not galvanize the world to action. Nor did the thousands of local deaths in the jungles of Thailand or Brazil. It took the death of Westerners, in increasing but still relatively small numbers, and the threat to formerly malaria-free areas of the world to resurrect the war against the ailment, many researchers say.

Diagnosis Difficult

Diagnosing and treating malaria in rural Africa is difficult because there is not enough medicine and there are few laboratories. Frequent wars further hamper attempts to provide health care. When a child in an African village dies, no one knows the exact cause. Malaria, chronic diarrhea and malnutrition should not be fatal diseases, but in rural Africa they frequently are.

Africa’s children may benefit from the increasing interest in malaria research, however, especially the efforts to find alternatives to expensive medications. Some doctors say, for example, that mosquito nets, used properly, would be the safest, most effective and most economical way to prevent malaria in rural areas.

Outside of Africa, Southeast Asia and Latin America, few physicians see patients with malaria, and they rarely think of it when confronted with a patient who has symptoms that resemble the flu--fever, nausea, headache, chills and a general malaise. But in Britain, judges have ruled in recent court cases that a physician who has a patient with a high fever should consider the possibility of malaria.

More Concern Urged

Dr. Christopher Nevill, who heads the malaria unit of the African Medical Research Foundation, thinks that the West should be more concerned about malaria.

The number of cases of imported malaria in Britain rose from 1,934 in 1984 to 2,212 last year. In the United States, about 1,000 cases of malaria are reported annually, and all of them are imported. Ten Americans died of malaria in 1984 and 12 died in 1985, according to the U.S. Centers for Disease Control in Atlanta.

The drug-resistant strains of malaria in East Africa were first detected in 1978. By 1984, hospitals along the coast were receiving calls from distressed physicians puzzled over why chloroquine was not working as well as it once had. Malaria patients once treated successfully in a doctor’s office were now requiring hospitalization.

Chloroquine was so widely and indiscriminately used for prevention and treatment that it simply began to lose its effectiveness against a disease known for its ability to foil attempts to kill it, experts say.

‘Successful Parasite’

“It’s really a very successful parasite,” said Dr. David Warrell, an Oxford University researcher who has studied cerebral malaria as director of the Wellcome Trust Research Laboratory in Bangkok, Thailand. “It constantly changes its characteristics, so the host’s defenses are always one step behind.”

Chloroquine-resistant strains are most prevalent on the east coast of Africa, along a 400-mile stretch from Lamu in Kenya to Dar es Salaam in Tanzania, and on the shores of Lake Victoria in western Kenya. About half of the malaria in eastern Kenya and 25% of it in the west is resistant to chloroquine, according to Dr. A. David Brandling-Bennett, an epidemiologist for the U.S. Centers for Disease Control working in Kenya.

“Chloroquine is by no means worthless, but it is no longer complete protection in East Africa, either,” he said.

An American church group that spent two weeks on an island in Lake Victoria last June was taking regular doses of chloroquine, as ordered by the doctors back home. When the group returned to Shreveport, La., however, six of the 10 travelers had malaria. They were treated with quinine and recovered.

War on Mosquitoes

Kenya’s president, Daniel T. Arap Moi, recently declared war on mosquitoes. Five Kenyans were jailed and given lashings for failing to combat the insects’ breeding by not clearing brush and keeping their property clean.

Anopheles mosquitoes can breed in virtually any collection of water, including irrigation ditches, hoof prints, ponds and brackish swamps.

Malaria is rare in central Kenya, including the capital, Nairobi, because of its cool, dry climate. The region is more than 5,000 feet above sea level. But conditions are nearly perfect for mosquito breeding in coastal Mombasa.

From March until July this year, during and following the long rains, Mombasa suffered its worst outbreak of malaria in many years. Pharmacies reported unusually high sales of chloroquine, in the liquid form used to treat patients in doctor’s offices.

Hospitals Fill Up

Patients with the more severe cases, usually resistant to chloroquine, ended up in the hospitals. One private hospital brought beds up from the basement and set them side by side, filling them all with patients who had malaria.

“When you got a call of a patient entering the hospital with malaria, you couldn’t wait until morning to see them,” said one doctor who asked not to be identified by name. He and his partner handled 250 cases of malaria--longtime residents as well as tourists--during those five months, he says.

He said that only two of his patients died, but more than half came to the hospital on stretchers, many of them in comas.

“Things were so bad that we would admit a patient and not even take a chance on chloroquine at all,” the doctor said. “We gave up on chloroquine.”

Wrong Advice

The foreigners who became seriously ill with malaria, a longtime Mombasa physician said, “were either ignorant about prophylaxis (prevention), had half-baked or wrong advice on prophylaxis, were repeat visitors who became overconfident, had religious beliefs that kept them from seeking treatment or were free-lance tourists trying to save money by living in hovels and huts.”

Barbara Allen, the former U.S. consul general in Mombasa, was especially conscientious about ensuring that her staff took anti-malaria tablets. That was why her friends were surprised to learn later that she had not been taking them herself, apparently because of her religious beliefs. She was a Christian Scientist.

Still, doctors here say that early treatment with quinine would have saved her life. She had been ill at home for seven days before relatives staying with her summoned medical help. The doctor found her drifting in and out of consciousness, a symptom of cerebral malaria. She was rushed to the hospital and treated, but she did not recover. Taken first to Nairobi, she was moved a week later to the United States, where she died.

Traditional Wisdom

People who live in Africa collect all sorts of traditional wisdom about how to avoid the disease. Some say that malarial mosquitoes only bite between 4 a.m. and 5 a.m. The truth is that they bite at any time after dark but do so most frequently after midnight.

Some say that malarial mosquitoes cannot survive at high altitudes or in cool weather. In fact, while malaria is most common in tropical climates, it has been transmitted at altitudes as high as 8,000 feet in Kenya and Bolivia, and even in the Arctic during the summer.

Some say that mosquitoes cannot reach humans sleeping on a high floor of a building. In fact, mosquitoes can and do ride elevators. Doctors report seeing occasional cases of “airport malaria” caused by mosquitoes arriving on trucks or airplanes from malarial areas. A baggage handler in Belgium last summer, for example, contracted malaria apparently after being bitten by a mosquito that had hitched a ride on a jumbo jet from Africa.

Changing Advice

The dwindling effectiveness of chloroquine in East Africa has left doctors both here and abroad in a quandary about what to recommend for visitors. The official U.S. Embassy recommendation has changed three times in the past year. A doctor in Mombasa gave these guidelines for tourists--take anti-malaria medication, stay at hotels with good pest control and seek immediate treatment for any flu-like illness.

An important factor is where the visitor plans to travel. While the disease is highly endemic on the coast, a popular vacation spot for Europeans, it is much less common in Kenya’s game parks, where most American tourists go, and almost unheard of in Nairobi.

Doctors disagree about the best combination of anti-malarial drugs to take and about whether to take preventive medication at all. But they agree that the best bet is to avoid being bitten. Because of the mosquito’s nocturnal feeding habits, sleeping under a mosquito net provides a lot of protection.

Research History

Research into the causes and prevention of malaria has blown hot and cold throughout recent history. In the late 1800s and early 1900s research boomed, the result of the growing desire among the world’s powers for commercial projects in the tropics. India, then a British colony, had a large malaria problem at the time. So did Panama, where the United States wanted to build a canal.

In 1957, the World Health Organization began a global malaria eradication program. The results were excellent in Europe and North America but less successful in tropical countries. The group scrapped the program 12 years later, replacing it with a more realistic control program. The program of control, aided by pesticides and drugs such as chloroquine, worked so well that funding for malaria research dried up.

But now the field is active again. Attempts to create a malaria vaccine have generated considerable excitement. The scientist who develops a vaccine against the world’s most widespread deadly disease seems a clear candidate for a Nobel Prize.

Preliminary Vaccine

Scientists at Walter Reed Army Institute of Research in Washington developed a preliminary vaccine but are reworking it after the results of initial trials were disappointing. A team at New York University also has begun initial trials of a vaccine but has not discussed the results.

It will not be easy to outsmart the disease, scientists acknowledge. The malaria parasite has years of experience at putting up smoke screens to trick the body’s immune system. Even Africans with natural immunity to Malaria must be reinfected every two years to maintain their protection.

The most optimistic experts say that a vaccine is probably years away.

“But we don’t know whether it can even be done,” one researcher said. “The bug may simply outwit the vaccine.”