World AIDS Day coming up on Sunday 1 December 2013 is not just a time to think about progress and challenges of one infectious disease, but the interaction between HIV and other infections, especially Malaria. Adu-Gyasi and colleagues express the relationship well in their article on malaria among HIV patients in Ghana: “Malaria is associated with an increase in HIV viral load and a fall in CD4-cell count. Conversely, HIV infection disrupts the acquired immune responses to malaria and the efficacy of antimalarial drugs.” Recent research provides continued insight that we must look at the two diseases as a joint problem in malaria endemic regions.
Research was conducted on mice that were infected with P. chabaudi malaria. The mice showed increased gut and genital mucosal T cell immune activation and HIV co-receptor expression. The implication of the findings was that malaria infection might enhance the sexual acquisition of HIV in humans, and the authors recommended further research to learn more.
In another study researchers looked at Malaria and HIV co-infection and their effect on haemoglobin levels from three health-care institutions in Lagos, Nigeria. The data showed that the total number of malaria infected patients were significantly higher in HIV sero-positive patients 47.7% (31/65) when compared with their HIV sero-negative counterparts 25.8% (262/1015) P = 0.047. Not only was there a higher prevalence of malaria in HIV infected patients but also patients co-infected with malaria and HIV were more likely to be anaemic.
Both HIV and malaria in pregnancy present serious problems. Another recent study looked at Cotrimoxazole (CTX) prophylaxis versus mefloquine (MQ) intermittent preventive treatment (IPT) to prevent malaria in HIV-infected pregnant women. The study concluded that, “CTX alone provided adequate protection against malaria in HIV-infected pregnant women, although MQ-IPTp showed higher efficacy against placental infection. Although more frequently associated with dizziness and vomiting, MQ-IPTp may be an effective alternative given concerns about parasite resistance to CTX.”
Concern about malaria and HIV in pregnancy also focuses on the child. Research examined malaria diagnosis in pregnancy in relation with early perinatal mother-to-child transmission (MTCT) of HIV. The authors reported that “HIV MTCT risk increased by 29% (95% CI 4-58%) per MIP episode. Infants of women with at least two vs. no MIP diagnoses were 2.1 times more likely to be HIV infected by 6 weeks old (95% CI 1.31-3.45).”
Finally since concurrent experience of both malaria and HIV infections means taking multiple drugs, researchers have also looked at the potential challenges of drug interaction. “An extensive literature search produced eight articles detailing n = 44 individual pharmacokinetic interactions.” While various HIV medications either increased or decreased the exposure to malaria drug components including lumefantrine and artemisinin, artemether-lumefantrine or artesunate combinations generally had little effect on the pharmacokinetics of HIV-antivirals (with two exceptions).
It is difficult to say which disease is closer to reaching elimination goals, but unless both are understood from their mutual impacts on transmission and treatment of the other, both will continue to elude control efforts.