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Man has known Malaria for centuries and AIDS has been
around for nearly 2 decades. Malaria has already killed millions and
continues to kill nearly 3 million every year. As of 1999, nearly 36
million people around the world are infected with HIV and 5 million
have died of AIDS related illness. And in the coming millennium,
both the diseases are expected to infect many more and to kill many
many more around the world. But the bigger tragedy is that HIV
infection is on a dramatic increase in those countries where malaria
is already a uncontrollable problem.
Many interesting studies
have been conducted on the relationship between these two potentially fatal diseases. Here
below you will find a summary of these studies:
Effect of HIV
infection on malaria:
With what we know of HIV
infection, it is only natural that one expects a far poorer outcome for malaria in HIV
infected patients. But on the contrary, the reports available indicate either no effect or
even a protective effect against death from complications of falciparum malaria!
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Malaria does not occur as an opportunistic
infection in patients with HIV infection.3
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Incidence of malaria is not more common in
HIV infected patients.1,3
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The response to antimalarial treatment is
identical in HIV infected and non-infected patients.3
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Although high levels of malarial
parasitemia have been observed in African children with symptomatic HIV infection,
these children have been found to be 'protected' against cerebral malaria and deaths due
to cerebral malaria. This has been attributed to lower levels of Tumor Necrosis Factor in
HIV infected children. TNF is reported to have a potentiating effect on the endothelial
adherence and clogging of microcirculation by parasitized red cells1. In an
animal study using mice, murine AIDS was found to confer protection against the severity
of neurological manifestations of experimental cerebral malaria and this protection was
higher with longer duration of immunodefeciency. Interleukin 10 from splenic cells was
shown to play a crucial role in this protection.2
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However, there are also studies that have
found no difference in the incidence, clinical features and response to treatment of
malaria among the HIV positive and HIV negative groups.3,6
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Patients with HIV infection may have a
false positive serological test for malaria. Therefore, serological tests for malaria may
not be useful as surrogate tests for assessing the travel status of individuals.4
Effect of malaria on
HIV infection:
It appears that malaria does
more harm to HIV patients and HIV transmission than vice versa. Many studies from the
African countries have thrown light on this aspect.
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It is common knowledge that in areas where
malaria is common, the health workers are assigned the job of conducting active
surveillance by screening the population for malaria by peripheral smear examination. It
is feared that this practice of collecting peripheral smears on a mass scale can certainly
heighten the risk of transmission of HIV infection through needle pricks.5
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Also in areas where malaria is common,
children and pregnant women often suffer from malaria related anemia and may require
transfusion of either whole blood or packed cells. This also increases the risk of
transmission of HIV infection as it may not be possible to ascertain the serological
status of the donor in areas where HIV is also rampant.6,7,8 Therefore it is
important to develop definite guidelines for blood transfusion in areas where anemia (due
to malnutrition, helminthiasis, malaria etc.) and HIV infection are prevalent.
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Malaria has potent immunosuppressive
effects. It has been found that patients with HIV infection who contact malaria tend to
deteriorate rapidly into AIDS Realted Complex or AIDS. Malarial infection supposedly
accelerates the replication of HI virus.9
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Chloroquine, the most commonly used
antimalarial has been found to have inhibitory effects on the antiviral activity of
Interferons alpha and beta in animal studies. It has also been found that chloroquine
enhances viral replication in mice. It may suggest a possible connection between AIDS and
malaria infection, since the spread of AIDS has been rapid in parts of tropical Africa
that have a high incidence of malaria and chloroquine has been frequently used in the
chemotherapy of malaria.10
Malaria and Kaposi's
sarcoma:
In sub-Saharan Africa,
Kaposi's sarcoma is a frequent tumor (endemic Kaposi's) and it has been blamed on
environmental factors. Kaposi's sarcoma also occurs in association with AIDS (AIDS
associated Kaposi's sarcoma). One study on the association of endemic Kaposi's sarcoma and
transmission of malaria based on the available data from 27 African countries found a
significant geographical association between proportional rate of Kaposi's sarcoma and
malaria transmission.11 The following possibilities have been suggested to
explain this association:
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The immunosuppressive effects of malaria
might be an additional cofactor in the pathogenesis of endemic Kaposi's sarcoma.
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Abnormalities of cell-adhesion, observed
as blood-flow sludging, have been observed in malaria as well as AIDS associated Kaposi's
sarcoma. This factor might be contributory to the pathogenesis of both AIDS associated and
endemic Kaposi's sarcoma.
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Kaposi's sarcoma may also be an arthropod
borne illness in Africa.
Interactions of antimalarial and
antiretroviral drugs:12,13,14 Research on interactions between
antiretrovirals and antimalarials has been lacking. One study found no interaction between
mefloquine and indinavir or nelfinavir. The results of a pharmacokinetic study of
mefloquine and ritonavir suggest that mefloquine reduces ritonavir blood levels by at
least 30%.
References:
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Dayachi F, Kabongo L, Ngoie K. Decreased
mortality from malaria in children with symptomatic HIV infection. Int Conf AIDS.
16-21 Jun 1991;2:164
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Eckwalanga M et al. Murine AIDS protects
mice against experimental cerebral malaria: down regulation by interleukin 10 of a T-
helper type 1 CD4+ cell-mediated pathology. Proc Natl Acad Sci USA. 1994 Aug
16;17:8097-101
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Muller O, Moser R. The clinical and
parasitological presentation of Plasmodium falciparum malaria in Uganda is unaffected by
HIV-1 infection. Trans R Soc Trop Med Hyg. 1990 May-Jun;3:336-8.
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Chrystie IL, Palmer SJ, Voller A,
Banatvala JE. False positive malaria and leishmania serology associated with HIV
positivity. Int Conf AIDS. 1993 Jun 6-11;2:763
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Risk of transmission of AIDS and other
blood-related diseases during routine malaria activities. Bull World Health Organ.
1991;2:242-3
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Greenberg AE. Studies of the relationship
between Plasmodium falciparum malaria and HIV infection in Africa.
Int Conf AIDS. 1989 Jun
4-9:983
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Fleming AF. Tropical obstetrics and
gynaecology. 1. Anaemia in pregnancy in tropical Africa. Trans R Soc Trop Med Hyg. 1989
Jul-Aug;4:441-8.
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Lackritz E, Campbell C, Hightower A, Ruebush T, Were J. Is the cure worse than the disease: anemia, malaria, blood transfusion
and child mortality in western Kenya. Int Conf AIDS. 1990 Jun 20;236(1):273,
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Weinke T, Schere W, Pohle HD. Malaria
tropica in HIV infection (German). Klin Wochenschr. 1990 May17; 68(10):533-6
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Maheshwari RK et al. Effect of interferon
in malaria infection. Immunol Lett. 1990 Aug;1-3:53-7.
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Baumann S, Geier SA, Noehl MA, Goebel FD.
On the epidemiologic association between endemic Kaposi's sarcoma and malaria.
Int Conf
AIDS. 1994 Aug; 1:(170):7-12
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http://web.amfar.org/treatment/SubCategory/ID875.ASP
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Schippers EF, Hugen PW, den Hartigh J, et
al. No drug-drug interaction between nelfinavir or indinavir and mefloquine in
HIV-1-infected patients. AIDS 2000;14:2794-5.
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Khaliq Y, Gallicano K, Tisdale C et al.
Pharmacokinetic interaction between mefloquine and ritonavir in healthy volunteers.
Br J Clin Pharmacol 2001;51:591-600.
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