The biggest killer in history has not been TB, nor has it been warfare. Even AIDS will not kill as many people as a parasite injected into the bloodstream by a female Anopheles mosquito: malaria.

Brought under control to a certain degree, malaria is once again rearing its ugly head across the African continent, killing a child every 20 seconds, and moving swiftly south into the warm northern areas of South Africa. Consistently every year, malaria kills as many as two and a half million people.

Not immune to malaria, South Africa is experiencing the worst season in three decades with more than 43 000 cases and 310 deaths reported since September last year and experts are warning that the worst is yet to come, particularly as there has been heavy rainfall over the past few weeks in KwaZulu/Natal, the Northern Provcince and Mpumalanga the country’s malaria hotspots.

The latest statistics are even more shocking when considered that the average for the previous three seasons was about 24 000 cases per year. “Experts have predicted that this season could even be more severe than the previous season,” said Dr Raj Maharaj, of Communicable Disease Control at the Health Department.

Maharaj attributed the increase to high rainfall and temperatures during the last two seasons as well as an increased movement of people across the borders.

But the biggest contributing factor, although not directly spelt out by the department, appears to be a prevalence of malaria parasites fast becoming resistant to anti-malaria drugs and mosquitoes becoming resistant to insecticides.

This was due to a number of reasons. Firstly, drug resistance in the parasite develops as a result of people taking sub-optimal dosages or they do not take the correct drugs.

Secondly, with increased worldwide travel, drug resistant parasites are being imported into South Africa.

Professor Maureen Coetzee, head of the Department of Medical Entomology at the SA Institute for Medical Research (SAIMR), says there is evidence that mosquitoes collected in northern KwaZulu-Natal may be resistant to the insecticide used for malaria control.

She said the larva of the mosquitoes were being exposed to the insecticides used for agriculture and this can lead to high levels of resistance which is what happened in West Africa.

“This means that your chances of being exposed to a vector mosquito is much higher,” she said. “Chances of infection are therefore much higher.”

Asked what the department of health was doing to counter this, Maharaj said pilot sites were being set up so that studies could be conducted on the populations in the risk areas to ensure that correct resistance data was collected which in turn influenced decision making.

Coetzee said researchers at the SAIMR and in the region where studying the problem in an effort to find alternative means of control.

A study looking at combination therapy was also about to be conducted in collaboration with Mozambique and Swaziland to look at the effectiveness of various drug combinations.

Studies conducted by the Medical Research Council and the provincial malaria programmes have shown a widespread resistance to chloroquine with resistance to sulfadoxine-pyrimethamine in KwaZulu-Natal, Maharaj confirmed.

Chloroquine, for long a reliable and dependable anti-malarial used for both treatment and prevention, is no longer effective in most areas of the world.

The resistance to drugs has prompted the World Health Organisation (WHO) to unveil a new programme to ensure the urgent development of new anti-malarial drugs.

To be called the “Medicines for Malaria Venture” the programme is born out of the need to develop new anti-malarial drugs for use in the third world.

Western pharmaceutical companies have resisted investing the hundreds of millions of rands required for the development of new anti-malarial drugs as the majority of residents in the world’s tropical countries are unable to afford first world medicine prices.

Maharaj said South Africa supported the venture because standardising drug regimens and protocols was important.

Malaria, caused by a parasite, is transmitted to humans by the bite of the anopheles mosquitoes, which is why early attempts at malaria control focus on the killing of mosquitoes.

The introduction of DDT, an effective insecticide, caused an initial decline in malaria, but it had serious adverse environmental effects and gave way to more expensive alternatives.

Maharaj said South Africa supported the total ban on DDT for agricultural uses, but would like to have DDT retained for use in malaria control programmes as it is a cheap and effective insecticide.

“However, DDT has been phased out of use in the malaria control programme in South Africa,” he said.

The WHO recently introduced its “roll back malaria” campaign. This is receiving World Bank funding and is intended to halve the number of malaria cases in the world within the next five years.

South Africa, Mozambique and Swaziland recently launched a R40-million, five-year programme aimed at controlling the spread of malaria by spraying high-risk areas, as well as looking at the effectiveness of various drug combinations.

Medinfo spokesperson Dr Steve Toovey pointed out that climate change and global warming were also on the side of the malaria parasite.

He said a vaccine, developed by the United States Navy showed great promise.

“This (control of malaria) is a big job, but can be done with the application of the correct control measures. What the success of this campaign really depends on is the willingness of governments to sustain malaria and mosquito control programmes,” Toovey said. -Health-e News

Infobox

Malaria is a parasitic disease that occurs when an infected Anopheles mosquito bites a person and injects malaria parasites into the blood. Four species of malaria parasites can infect humans and cause illness; only P. falciparum malaria is potentially life threatening. Most of the malaria found within Southern Africa is of the falciparum species. This is potentially the most dangerous species of malaria, and can prove rapidly fatal.

Symptoms may develop as soon as seven days after arrival in a malarious area, or as long as three months after leaving a malarious area.

Symptoms of malaria are often mild in the initial stages, resembling influenza.

Every year a hundred million episodes of malaria occur in Africa.

Malaria symptoms

• Fever
• Muscle aches and pain
• Sore throat and general flu-like symptoms
• Diarrhoea
• Headache
• Confusion
• Coma

What to do if you suspect you have malaria

• Seek immediate treatment from your local clinic, doctor or hospital
• Ensure that a blood tests is taken to test for the prevalence of malaria
• If the first test is negative have another to be absolutely sure
• Assume all flu-like illnesses of fever occurring within six months of returning from a risk area to be malaria until proven otherwise

How to prevent malaria when travelling

• Seek advice before departing for a potentially malarious area
• Take the full course of anti-malarials prescribed, including for four weeks after your return
• Wear a mosquito repellent
• Wear long sleeves and trousers, especially at night
• Sleep under a mosquito net, impregnated with permethrin or in an air-conditioned room

Children younger than five years and pregnant women are particularly at risk and should avoid travelling to a malarious destination