Malaria defies new drugs to make a comeback

Malaria, one of the world's biggest killers, is defying new treatments and spreading rapidly, threatening to create a major world-wide public health disaster, scientists say.

Exactly 100 years since Sir Ronald Ross discovered that mosquitoes were responsible for carrying the deadly parasite, mankind is losing the battle against the disease.

Today, 650 scientists and public health officials from around the world are marking the anniversary in Hyderabad, India, with a meeting to consider a global strategy to curb the rise in cases, numbers of which are estimated to have quadrupled in the past five years.

Experts fear that unless action is taken to control the disease, the growth of drug resistance, global migration of the disease and climatic changes will threaten new areas with malarial infection and further increase the toll of death and disease.

Malaria strikes 500 million people a year, causing almost 3 million deaths, most among children. Despite the scientific and medical advances of recent decades, it kills more people today than in the Sixties.

Brian Greenwood, professor of communicable diseases at the London School of Hygiene and Tropical Medicine, said: "Malaria is the most prevalent and neglected parasitic infection. An estimated 40 per cent of the world's population is at risk."

The World Health Organisation (WHO) predicts that an extra 80 million people a year will be infected by the end of the century, a 16 per cent rise in three years.

In India, the malaria eradication programme of the Fifties and Sixties reduced infections from 75 million to 100,000 a year, and deaths from 800,000 to almost none. That trend has reversed over the past two decades and there have been four major epidemics since 1994. Last year there were almost 3 million cases and at least 3,000 deaths.

The Malaria Foundation, an international group of scientists set up in 1992, yesterday called for a new political commitment and for increased funding to combat the disease.

Dr Dan Colley, director of the division of parasitic diseases at the Centre for Disease Control in Atlanta, Georgia, said: "There is an urgent need for concerted action to control malaria now, before drug and insecticide resistance, population shifts and potential climatic changes combine to further expand this major world-wide public health disaster."

Thirty years ago malaria had been eradicated, or dramatically reduced, in 37 countries as a result of the WHO insecticide spraying programme, but many of the programmes have since been abandoned, partly because of cost and partly because of declining motivation in the face of an apparently declining threat.

Drug resistance has increased rapidly as a result of widespread use of malaria treatments in an unregulated and uncontrolled way. Most tropical countries rely on chloroquine because it is cheap but the drug is increasingly ineffective. In some areas resistance has also developed to the newer drug mefloquine (Lariam) which many people are reluctant to take because of side effects such as dizziness.

Mefloquine is none the less recommended for Western tourists visiting areas where the plasmodium falciparum species of parasite, the major cause of malaria deaths, is endemic.

The foundation claims that too little is spent on malaria research compared with other diseases such as Aids and asthma that cause fewer deaths. It says global research spending on Aids is $3,274 (pounds 2,040) per death compared with $789 per asthma death and $65 per malaria death.

The Wellcome Trust has announced a three-year project to work out the full genetic sequence of the malaria parasite, to identify features that may be susceptible to attack by drugs.

Malaria was common in England until the last century but had disappeared by 1930. Medical historians claim that in addition to better housing and wider availability of drugs, the introduction of the turnip as a winter feed for cattle may have had an unexpected benefit. The turnip meant that more animals could be kept alive through the winter instead of being slaughtered, and mosquitoes preferred to bite cows rather than human beings.