5 Opportunistic infections (OIs) and coinfections

5.15 Malaria

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Type of illness

Malaria is a parasitic infection of red blood cells.

Malaria is transmitted to humans by a bite from a female Anopheles mosquito. There can be a delay of 1 week to 1 year between getting infected and having symptoms.

Most people who grow up in malarial areas have some immunity to the illness. Malaria is usually an acute (short-term) illness, but for some people it becomes a chronic (life-long) problem.

The risk of malaria is related to where you live and whether this is in a high-risk country or region, and by season. Malaria is the one of the leading causes of death in children under 5 who live in areas affected by malaria.

In people with HIV:

• acute infection is not an OI
• chronic malaria is considered a coinfection

Main symptoms

• Shaking chills
• High fever and sweating
• Dizziness, nausea, vomiting, abdominal cramps
• Headache and back ache
• Tiredness
• Sometimes jaundice (yellowing of skin and eyes)

Malaria attacks happen over 4 to 6 hours, and occur every 2 or 3 days.

If malaria affects the brain, it can be fatal within 24 hours.

Malaria can cause anaemia.

Malaria and HIV

HIV-positive people are at a higher risk of malaria infection, and the disease is more severe. HIV makes malaria worse.

• There is a higher density of parasites.
• The symptoms last for longer
• A low CD4 count and high viral load increases this risk
• There is an increased risk of reinfection (with a new infection) within 28 days of treatment
• Malaria increases HIV viral load which may affect long term health
• It is not like a typical OI because childhood immunity is often retained in adults

Malaria, pregnancy and anaemia

Pregnant women are 3 times more likely to catch malaria compared to non-pregnant women.

The increase in viral load from malaria coinfection increases the risk of HIV transmission in HIV-positive pregnant women, and causes lower birth weight in the baby.

Haemoglobin levels are lower in coinfected pregnant women and the risk of anaemia is higher. This has to be taken very seriously and managed appropriately.

This usually means that the risks from not treating malaria are greater than the difficulties from treatment (ie drug interactions).

Diagnosis

Malaria is diagnosed by physical examination and blood tests. Information about travel history and symptoms are important.

Treatment

Malaria can be treated with inexpensive drugs and can usually be cured. The choice of drugs depends on whether the malaria in your region has developed resistance to treatment.

Malaria is usually treated with a combination of drugs. Several anti-malarial drugs and combinations are available.

• chloroquine-based treatment used to be the most widely-used first line therapy, and the most effective therapy, but is now one of the drugs to which there is most resistance
• artemisinin + lumefantrine are now more widely used in chloroquine-resistant regions

Interactions with HIV drugs are complicated.

• halofantine – don't give with PIs
• artemether – don't give with PIs, levels reduced by nevirapine and efavirenz
• lumefantine – don't give with PIs, levels reduced by nevirapine and efavirenz
• quinine – unclear if there are PI or NNRTI interactions

Prophylaxis

One of the most effective ways to stop malaria is to use insecticide-treated bed nets, which cost less than $5 and can reduce all-cause child mortality by 25%. This is part of a major international campaign to reduce infant mortality from malaria.

Oral prophylaxis is with co-trimoxazole (Septrin), which also protects against PCP and toxoplasmosis

Research

Research on malaria is looking at the following areas:

• Resistance to treatment is a serious problem – new drugs are being looked at.
• Effect of malaria in HIV-positive children.
• Does better malaria treatment improve management of HIV?
• Implications of co-trimoxazole treatment for protection and the risk of resistance.
• Drug interactions between malaria treatment and ARVs.
• Vaccines.