Interplay Between HIV and Malaria in Sub Saharan Africa
HIV and malaria are leading causes of morbidity and mortality in sub Saharan Africa. The overlap of these diseases could have substantial population level implications, making it crucial to understand the interaction between the two.
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1. Interaction of HIV and Malaria Malaria Branch Division of Parasitic Diseases National Center for Infectious Diseases SAFER HEALTHIER PEOPLE
2. Malaria and HIV disease in sub Saharan Africa Malaria and HIV are leading causes of morbidity and mortality, particularly in sub Saharan Africa Both diseases are highly endemic and have a wide geographic overlap A small effect of malaria on HIV or vice-versa could have substantial population-level implications HIV Malaria
3. Malaria and HIV disease in sub Saharan Africa Background on malaria What we do and dont know: Malaria <-> HIV interaction Science & program
4. Scope of the Malaria Problem: Malaria is the most common life-threatening infection 1 million deaths/yr 300-500 million infections/yr ~ 90% of these deaths occur in sub-Saharan Africa most victims are children <5 yrs Pregnant women are also especially vulnerable.
5. MALARIA 101 Human Malaria is caused by one of 4 protozoan parasites: Plasmodium falciparum Plasmodium vivax Plasmodium ovale Plasmodium malariae Malaria is transmitted through the bite of an infected female Anopheles mosquito
6. Liver stage Sporozoites Mosquito Salivary Gland Malaria Life Cycle Gametocytes Oocyst Red Blood Cell Cycle Zygote
7. MALARIA 101 clinical syndromes Chronic Disease Chronic or Recurrent Asymptomatic Infection Placental Malaria & Anemia Anemia Infection During Pregnancy Developmental Disorders Transfusions Death Low Birth weight Increased Infant Mortality Acute Disease Non-severe Acute Febrile disease Cerebral Malaria Death
8. Effective Malaria Interventions Include: Providing prompt access to curative treatment Preventing and controlling malaria during pregnancy Promoting the use of insecticide-treated mosquito nets shown to reduce all-cause child mortality by 20%-25%
9. Malaria Interventions - Costs Insecticide-treated mosquito nets: $2.50 -- 5.00 Malaria treatment: CQ, SP, AQ, Lap-Dap: $0.10 0.50 Artemisinin-combinations: $2.00 or more Intermittent Preventive Tx in preg: $0.35
10. HIV and Malaria Interaction
11. Early studies mid/late 1980s HIV transmission modes: mosquitoes? Does HIV make malaria worse? Does malaria make HIV worse? Malaria is not an opportunistic infection Curious because CD4-dependant immune response is thought to be important for malaria Malarial anemia blood transfusion HIV infection No probably No
12. Recognition of the effect of HIV on malaria in pregnant women Malawi study (1987-1991): During pregnancy, malaria was more common and of higher density in HIV(+) vs. HIV(-) women These findings were repeated in other studies and countries -Malawi (2 sites), Kenya (3), Rwanda (1)
13. Placental parasitemia by HIV status and pregnancy number, Kenya Parasite density/mm 3 % parasitemic HIV (+) HIV (-) 231 159 197 772 402 479 Total n = 2263 Summary RR = 1.63 (1.41-1.89), p<0.001
14. Current knowledge Malaria and HIV interactions Does HIV make malaria worse? Does malaria make HIV worse? Anemia and Blood safety Pregnant women and their fetus/newborn Non-pregnant adults Children Program overlap
15. Anemia and Blood Safety Not much new to report Remains a serious problem Despite available technology, universal blood screening is not yet achieved, especially in some high HIV prevalence settings Important unmet needs include: anemia prevention clarity on best criteria to limit transfusions except when truly needed universal and quality-controlled HIV testing
16. Pregnant women and their fetus/newborn HIV does make malaria in pregnancy worse More and higher density malaria, more illness, more anemia, more low birth weight Malaria may make HIV worse Higher HIV viral load ? impact on Mother-to-Child Transmission (MTCT)
17. HIV-associated Risk of Placental and Peripheral Parasitemia in Pregnant Women 1.27 1.70 2.39 1.60 1.58 0 1 2 3 Placental parasitemia (4 studies) Primigravidae 389 HIV+; 1589 HIV- Secundigravidae 241 HIV+; 774 HIV- Multigravidae 382 HIV+; 1606 HIV- Total 982 HIV+; 4049 HIV- Peripheral parasitemia (7 studies) 2336 HIV+; 8667 HIV- Relative risk (95% CI) *
18. Hemoglobin Level by HIV Status Malaria and Gravidity Kisumu, Kenya, 1996 1999 (N= 4,608) van Eijk et al, AJTMH, 2001
19. HIV and Malaria: Associated Reductions in Mean Birth Weight (grams) Kisumu, Kenya, 1996-99 (N=2,466) Primi-gravidae Multi-gravidae HIV alone 44 (-32-112) 138 (78-199) Malaria alone 145 (82-209)* 8 (-71-88) Dual infection 206 (115-298)* 161 (63-259) *In Primigravidae, both malaria (RR 2.24, p=0.003) and dual infection (3.45, p<0.001) associated with significant increased relative risk of LBW (< 2,500 grams) compared with uninfected women Ayisi et al, AIDS, 2003
20. Effect of HIV on Malaria illness in pregnancy Kisumu, Kenya, 1996-1999 N=2539 Prevalence RR (95% CI) HIV (24.9%) HIV+ HIV- Clinical malaria 9.4% 3.1% 3.01 (2.36-3.85) Hospitalization (all causes) 4.3% 2.7% 1.59 (1.16-2.20) van van Eijk et al, AIDS, 2003
21. Does HIV make Malaria worse? Pregnant women, fetus, and newborn In western Kenya, where HIV prevalence in pregnant women exceeds 25% HIV accounts for one-quarter of all malaria infections in pregnancy HIV contributes to anemia, low birth weight, and poor infant survival (in both HIV+ and HIV- infants) Nearly one-half of all malarious sub-Saharan African countries have HIV seroprevalence in pregnant women in excess of 10%
22. Pregnant women and their fetus/newborn HIV does make malaria in pregnancy worse More and higher density malaria, more illness, more anemia, more low birth weight Malaria may make HIV worse Higher HIV viral load ? impact on Mother-to-Child Transmission (MTCT)
23. Malarias impact on HIV Replication Malaria antigens induce HIV-1 replication in-vitro (Xiao et al, JID, 1998) HIV transgenic mouse model -- Murine malaria triggered increased P24 antigen production (Freitag, JID 2001)
24. Malaria and HIV viral load in pregnancy Dar es Salaam, Tanzania (Kapiga et al, JAIDS, 2002): Peripheral viral load >2-fold higher in parasitemic pregnant women Kisumu, Kenya (Ayisi, in press) Peripheral viral load 1.4-fold higher in parasitemic women (p=0.096); viral load with parasite density Blantyre, Malawi (Victor Mwapasa, 10 th CROI, Boston, 2003) Placental viral load 2.4-fold higher in HIV+ women with placental malaria than in those without malaria Mangochi, Malawi (Tkachuk et al. JID 2001) Significant 3-fold higher CCR5 mRNA expression in placentas of malaria-infected women
25. Malaria contribution to HIV-MTCT? Malawian pregnant women (Bloland, AJTMH 1995) Malaria and HIV co-infection Infants born to dually infected mothers had increased post-neonatal mortality, beyond independent risk associated with exposure to either maternal HIV or placental malaria Increased viral load or altered placental architecture increased MTCT? * MTCT = Mother-to-child transmission
26. Malaria contribution to HIV-MTCT ? Bloland et al. >> Infant mortality Verhoeff et al. << Infant mortality St Louis et al. No association Brahmbhatt et al. RR 2.9 (1.1 -7.5) Inion et al. RR 0.6 (0.2-1.7) Mwapasa et al. RR 1.2 (0.7-2.3) Ayisi et al. RR 0.4 (0.3-0.7)
27. Placental Malaria & HIV-MTCT Kisumu, Kenya, 1996-1999 Ayisi et al, in press EID 512 mother-infant pairs with known perinatal HIV transmission status 128 women (25%) had placental malaria 102 infants (20%) acquired HIV perinatally by 4 months (HIV DNA PCRs). Ayisi, in press
28. Perinatal HIV Transmission by Placental Malaria Density Kisumu, Kenya 1996 - Ayisi et al, in press
29. Potential Immunologic Basis: Effect of Malaria on MTCT Placental malaria Low density High density Th1 response HIV replication MTCT LIF MIP-1-beta Block cellular entry HIV TNF-alpha HIV replication MTCT MIP-1-beta = Macrophage Inflammatory Protein-beta; LIF = Leukemia Inhibitory Factor
30. Conclusions: Malaria & HIV during pregnancy Some clear interactions Preventing/managing placental malaria and HIV would reduce maternal anemia and low birth weight Some unclear interactions that require characterization Will clearing placental malaria affect MTCT ?
31. Non-pregnant adults HIV with immune compromise (CD4 depletion) does make malaria in adults worse More malaria, higher density parasitemia, more illness, more severe disease Reduced efficacy of antimalarial therapy? Malaria may make HIV worse Higher HIV viral load Impact on clinical illness?; survival?; transmission?
32. Non-pregnant adults HIV with immune compromise (CD4 depletion) does make malaria in adults worse More malaria, higher density parasitemia, more illness, more severe disease Reduced efficacy of antimalarial therapy? Malaria may make HIV worse Higher HIV viral load Impact on clinical illness?; survival?; transmission?
33. Impact of HIV on malaria in non-pregnant adults Advanced HIV immunosuppression is associated with higher density parasitemia and more clinical illness in adults French et al, AIDS 2001; Whitworth et al. Lancet 2000; Francesconi et al, AIDS 2001. Advanced HIV immunosuppression is also associated with poorer response to malaria treatment Shah S et al, personal communication 2004
34. Non-pregnant adults HIV with immune compromise (CD4 depletion) does make malaria in adults worse More malaria, higher density parasitemia, more illness, more severe disease Reduced efficacy of antimalarial therapy? Malaria may make HIV worse Higher HIV viral load Impact on clinical illness?; survival?; transmission?
35. Malaria contributes to increased HIV Viral Load Several intercurrent infections have been shown to increase HIV replication in vivo: Mycobacterium tuberculosis Mycobacterium avium complex Pneumocystis carini Herpes simplex STIs?
36. Studies of the effect of malaria on HIV RNA levels Malawian adults with acute malaria 7-fold increase in HIV-1 viral load Reversible with treatment (in some patients) Induction of HIV-1 replication in CD14 macrophages Hoffman, 1999; Pisell, 2002 Follow-up study in Malawian adults Kublin et al, 2003 Am Soc Trop Med Hyg Mtg
37. Clinical & public health significance Individual Brief increase in viral load due to malaria may worsen clinical prognosis Population Higher viral load associated with higher infectivity Probability of HIV transmission may be elevated around a malaria episode, especially during the lag time post-malaria before RNA levels return to baseline
38. Infants and Children Difficult to study Low incidence/prevalence of HIV in this group Already highly susceptible to malaria and HIV- associated immune deficiency may not make this susceptibility much worse Dual Malaria and HIV is associated with poor outcome Anemia Survival?
39. Malaria in HIV+ infants Kisumu, Kenya, June 1996-April 2000 HIV+ infants were not at risk of more malaria parasitemia higher parasite density However, if parasitemic, were at risk to: be febrile have severe anemia have splenomegaly be admitted to the hospital Source: van Eijk et al, unpublished
40. Hemoglobin in infants by HIV status and malaria Kisumu, Kenya, June 1996-April 2000 Source: van Eijk et al, AJTMH, 2002
41. Post-neonatal Infant mortality by maternal HIV-status and placental malaria Kisumu, Kenya, June 1996-July 2001 , N=866 A: No infection (N=96) B: placental malaria only (N=117) D: HIV only (N=494) C: Dual infection (N=159) A B C D Source: van Eijk et al, unpublished A vs C or D: P <0.01 A vs B: P =0.06
42. Malaria and HIV biologic interactions summary 2004 HIV-associated immunosuppression contributes to more and worse malaria and its consequences in adults, pregnant women, and children. Malaria contributes to stimulus of HIV replication and possibly(?) to its consequences: disease progression, transmission in adults, and MTCT. Co-infection with Malaria and HIV in pregnant women contributes to anemia, low birth weight,and their risk for poor infant survival. Malarial anemia in children too frequently requires blood transfusion and may still lead to HIV transmission
43. Malaria & HIV program overlap Population overlaps Anemic children; pregnant women; adults with CD4 Intervention overlaps Diagnostics Treatments: complexity and costs of Tx, resistance Protease inhibitors block endothelial CD36 binding of malaria-infected red blood cells OI prophylaxis with co-trimoxazole (an antimalarial) HIV-infected persons need malaria prevention Site of activity overlaps GFATM and Country Coordinating Mechanisms Antenatal clinics; under-5 clinics; communities, VCT sites? ARV delivery systems
44. Malaria & HIV program overlap Recommendations for coordinated program action Jointly strengthen health service delivery: Laboratories Antenatal and delivery care ITNs & IPT for malaria; VCT & MTCT prevention Child care anemia prevention Specific Interventions ITN distribution with ARV delivery Use highly efficacious antimalarials in HIV+ persons with malaria infection HIV+ persons on cotrimoxazole for OI prophylaxis who get malaria should receive highly effective antimalarials