With the summer season comes along excessive heat, rains and humidity. As a result, certain parts of the country like the northern parts of Limpopo, eastern Mpumalanga and northern KwaZulu-Natal, are likely to breed conditions for the development of malaria-causing mosquitoes. The parasites are particularly dangerous for all at this time of the year, but they can introduce even greater havoc in people with HIV, according to Professor John Frean, head of the Microbiology Division at the National Institutes for Communicable Diseases (NICD), in Johannesburg.
‘It’s not surprising that there would be some influence of HIV on malaria because HIV affects the cellular immune system, which is very important in combating malaria’, Professor Frean says.
In South Africa, malaria is not endemic. It occurs seasonally from about September to May, with the peak periods being the months of January and February. Because of malaria being a seasonal disease, South Africans do not acquire any immunity to the parasitic infection as they are not exposed to it enough during a lifetime. Hence, when malaria strikes, it often has severe consequences.
‘We have to distinguish between two groups of people with malaria. Those who are what we call semi-immune’¦ They’ve grown up in malaria-endemic areas’¦ they’ve been exposed from an early age’¦ They have a certain amount of resistance. One never develops absolute resistance to malaria, but they are able to tolerate the infection much better than the other group of patients who are people who have grown up in areas where malaria is not endemic. It may occur on a seasonal basis ‘ what we call unstable malaria. Those individuals in unstable malaria areas are not semi-immune to malaria and they are more susceptible to the severe effects of malaria, and HIV places them at even greater risk’, explains Professor Frean.
‘Children living in high transmission areas – with their first attack, may die ‘ and a lot of children do. But repeated infections, with time – and these are very frequent infections – they will acquire some immunity so that by the time they are adolescents or young adults their malaria illness is usually very mild or even asymptomatic’, adds NICD Deputy Director, Professor Lucille Blumberg.
But if one has HIV this semi-immunity becomes lost.
‘HIV does change that and people living in high transmission areas, who might have acquired some immunity, if they are HIV-infected they will present more commonly with clinical malaria rather than being asymptomatic, they may have a higher number of parasites and some people may be susceptible to more severe malaria’, says Blumberg.
‘People with HIV who get malaria are liable to get more serious infections, more likely to become severe and complicated and have an increased risk of death, especially in areas where medical facilities are not that good or the high standard of care required to treat a patient with severe malaria is not present ‘ intensive care units, for example’, Frean adds.
But a compromised immune system is not the only risk factor. Professor Blumberg says people often don’t take malaria symptoms, which usually start with a fever, seriously.
‘I think, particularly for people in South Africa, we’ve noticed delays in seeking care for an acute illness with fever if you’re living in a malaria area ‘ and that would be what we’d encourage because, especially, if they’re not on ARVs, other infections are quite common and they attribute it – the fever they’re having ‘ to the usual HIV-associated infection and they don’t think about the malaria. I think you’re getting late presentation, delayed diagnosis and, because of that, an increased risk of complications and an increased risk of a fatal outcome’, she says.
Blumberg warns that it’s very important for people not to misinterpret the symptoms.
‘If you’re not living in a malaria area and aware of malaria, you may ignore that fever or you may think it’s flu. The symptoms over-lap. And if you look back on people who have died of malaria, often the first misdiagnosis was flu ‘ fever, head-ache, cold shivers, hot sweats, muscle pain. It’s just like flu. And both the person affected and the health care worker may make that error. So, I think a high index of suspicion for malaria, especially during the season, in anybody who lives in a malaria area or has traveled to a malaria area is very important’, she says.
About 7 000 cases of malaria are recorded annually in the malaria-prone areas of South Africa. And about 40 ‘ 80 people die as a result of the infection, with the majority of deaths occurring in people who have HIV.