On a cloudy Monday morning in the Mozambican capital, Maputo, Cremilda Bulha, 28, dressed in a white T-shirt and traditional capulana cloth skirt, waits in the outpatient line at Maputo Central Hospital.

With the same certainty as she comments "there's going to be more rain today," to the patient next to her, she tells IRIN/PlusNews: "I've got malaria."

The viral disease is spread by the Anopheles mosquito and causes headaches, fatigue, high fever, nausea and, in some cases, death. The number of malaria cases goes up during the rainy season, because mosquitoes breed in stagnant water.

Besides having to deal with these symptoms, Bulha is pregnant with her second child and is also HIV-positive, which increases her likelihood of catching malaria.

Susana Nery, a public health specialist from the Malaria Consortium organisation, explains that in countries like Mozambique, where the disease is endemic, people are bitten repeatedly and gradually build up resistance.

This protective shield weakens in pregnant women, HIV-positive people and children, making them more susceptible. "These people's immunological system fails and their natural resistance diminishes," Nery said.

In the first six months of 2007, 2.5 million cases of malaria were recorded after floods hit the country, and 1,518 patients died, according to the Ministry of Health.

Only half right

After two hours the nurse calls Bulha's name and the rain starts again. Her first forecast was right, but the second was wrong: her malaria test came back negative.

She is three months pregnant and began antiretroviral (ARV) treatment two months ago, but it is her pregnancy, more than the HIV, that makes her more vulnerable to the malaria virus.

Maputo Central Hospital physician Rui Bastos explains that HIV-positive individuals are more likely to get malaria only when their immunological system is debilitated - in other words, when HIV infection has progressed to AIDS, which is not the case with Bulha.

Her defence cell (CD4) count is high, and she is only taking ARVs to prevent transmission of the HIV virus to her unborn child.

But when in the AIDS phase it is important for HIV patients to take special care to guard against malaria, says Eduardo Mondlane Medical School professor Armindo Tiago Junior.

A person with malaria may be hospitalised for an average of three days; for a patient who is also HIV-positive this increases to a week. "The weak immunological system takes longer to react against malaria," the physician explained.

Mozambique has an HIV prevalence of 16.2 percent in a population of 19.8 million. The rate of malaria among pregnant Mozambican women is approximately 20 percent, according to data from the National Malaria Control Programme.

In 2004, Health Alliance International, a US-based global healthcare organisation, analysed 5,528 pregnant women in the provinces of Sofala and Manica, and in all instances found more cases of malaria among HIV-positive women than among HIV-negative ones.

As a Health Ministry policy, from the 20th week of pregnancy all expecting mothers must undergo intermittent presumptive treatment (IPT), in which they take a series of prophylactic pills that reduce the probability of contracting malaria. If they are undergoing ARV treatment, care needs to be doubled, said Tiago Junior.

When taken together, the ARV, nevirapine, and the anti-malarial medication, sulfadoxine-pyrimethamine, provoke vomiting and abdominal pain as well as reactions in the skin, such as blemishes, and in the mucous membranes, so the two drugs are never prescribed simultaneously.

The doctor makes a choice according to what he concludes is more important to the patient. If necessary, a different medication is used in place of the anti-malarial or the ARV.

The distribution of mosquito nets, especially to pregnant women, is one of Mozambique's main strategies to combat the disease. In the past three years, the Malaria Consortium and the Red Cross of Mozambique have distributed more than 700,000 nets in the northern provinces of Cabo Delgado and Nampula, the central provinces of Manica and Sofala, and Inhambane Province in the south.

The provinces included in the programme were chosen by the Ministry of Health based on the incidence of the disease and the shortage of health assistance.

While she waited for the rain to let up, Bulha commented: "This is just the kind of weather malaria likes." Although she is taking ARVs and undergoing anti-malaria treatment, Bulha covers her bed every night with the mosquito net she got at the beginning of the year. "That's what's going to protect me. Since I got it I haven't had malaria again."