HIV, malaria parasites, and acute febrile episodes in Ugandan adults: a case-control study

Temporal and Spatial Distribution of Opportunistic Infections Associated with the Human Immunodeficiency Virus (HIV) in Uganda

The human immunodeficiency virus (HIV) remains one of the greatest challenges of the twenty-first century in the absence of an effective vaccine or cure. It is estimated globally that close to 38 million people are currently living with the HIV virus and more than 36 million have succumbed to this deadly virus from the time the first case was reported in early 1980s. The virus degrades the human body immunity and makes it more vulnerable to different kinds of opportunistic infections (OIs). However, with the introduction of highly active anti-retroviral therapy (HAART) in 2003, the pattern and frequency of OIs has been progressively changing though with variations in the different parts of the World. So this chapter discusses the temporal and spatial patterns of OIs in Uganda.

Malaria prevalence in HIV-positive children, pregnant women, and adults: a systematic review and meta-analysis

Background

Malaria in human immunodeficiency virus (HIV)-positive patients is an ever-increasing global burden for human health. The present meta-analysis summarizes published literature on the prevalence of malaria infection in HIV-positive children, pregnant women and adults.

Methods

This study followed the PRISMA guideline. The PubMed, Science Direct, Google Scholar, Scopus and Cochrane databases were searched for relevant entries published between 1 January 1983 and 1 March 2020. All peer-reviewed original papers evaluating the prevalence of malaria among HIV-positive patients were included. Incoherence and heterogeneity between studies were quantified by the I2 index and Cochran’s Q test. Publication and population biases were assessed with funnel plots, and Egger’s regression asymmetry test.

Results

A total of 106 studies were included in this systematic review. The average prevalence of malaria among HIV-positive children, HIV-positive pregnant women and HIV-positive adults was 39.4% (95% confidence interval [CI]: 26.6–52.9), 32.3% (95% CI = 26.3–38.6) and 27.3% (95% CI = 20.1–35.1), respectively. In adult patients with HIV, CD4+ (cluster of differentiation 4) < 200 cells/µl and age < 40 years were associated with a significant increase in the odds of malaria infection (odds ratio [OR] = 1.5, 95% CI = 1.2–1.7 and OR = 1.1, 95% CI = 1–1.3, respectively). Antiretroviral therapy (ART) and being male were associated with a significant decrease in the chance of malaria infection in HIV-positive adults (OR = 0.8, 95% CI = 0.7–0.9 and OR = 0.2, 95% CI = 0.2–0.3, respectively). In pregnant women with HIV, CD4+ count < 200 cells/µl was related to a higher risk for malaria infection (OR = 1.5, 95% CI = 1.1–1.9).

Conclusions

This systematic review demonstrates that malaria infection is concerningly common among HIV-positive children, pregnant women and adults. Among HIV-positive adults, ART medication and being male were associated with a substantial decrease in infection with malaria. For pregnant women, CD4+ count of < 200 cells/µl was a considerable risk factor for malaria infection.

Graphical Abstract

PREVALENCE AND CLINICAL FORMS OF MALARIA AMONG FEBRILE HIV-INFECTED CHILDREN SEEN AT USMANU DANFODIYO UNIVERSITY TEACHING HOSPITAL, SOKOTO, NIGERIA

BACKGROUND

Malaria and HIV infections are major health problems facing the world today. Sub-Saharan Africa with 10 percent of world's population harbors more than half the burden of the scourge. The present study determined the prevalence and clinical forms of malaria among febrile HIV-infected children aged 3months to 15years, seen in Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, Nigeria.

MATERIALS AND METHODS

Cross-sectional study among febrile HIV-infected children and their control cohort were carried out between May and October 2016. The participants had the following investigations: malarial parasite, packed cell volume, random blood sugar, retroviral test.

RESULTS

A total of 140 febrile HIV-infected children aged 3 months to 15 years and 140 febrile HIV-negative age- and gender-matched children were recruited; 100 of the HIV-infected children were on ART and cotrimoxazole. The prevalence of malaria among the febrile HIV-infected children was 71.4% (100/140) which was significantly lower than the prevalence of 94.3% (132/140) among the control group (χ2 27.72, p=0.001). Among the febrile HIV-infected children that had malaria, 54(54.0%) had uncomplicated malaria while 46(46.0%) had severe malaria. Of the 132 controls that had malaria, 48(36.4%) had uncomplicated malaria and 84(63.6%) had severe malaria (χ2 =7.184, p=0.007).

CONCLUSION

Malaria is a problem in HIV-infected children. Since nearly half of the febrile HIV-infected children had severe form of malaria, it is recommended that health promotion, intermittent malaria prophylaxis, early diagnosis and prompt effective treatment should be instituted for HIV-infected children. This may prevent severe form of malaria and its attendant mortality.

Effects of malaria/helminthic coinfections on cervical cancer progression among sub Saharan African women on highly active antiretroviral therapy: A scoping review

In Africa, the HIV prevalence in rural areas has begun to reach levels estimated within urban settings, where women are also more at risk for both malaria and intestinal parasitic infections. The objective of this review is to assess whether concomitant infections with malaria and/or helminthic diseases have an impact on cervical disease progression in women on HAART. This scoping review was conducted in August 2018. To conduct this scoping review, we searched the relevant studies in electronic databases such as PUBMED, Global Health, EMBASE, CINAHL and SCOPUS published in the year between 1960 and 2018 using the following search terms HAART AND malaria OR Helminth and Female OR women. Eight studies qualified for this review. The literature underscores the need for women on HAART with multiple co-infections to use adjuncts to retain immune recovery and undetectable HIV viral load, to reduce risk of cervical disease progression. A trend for higher risk of CIN3+ in HIV+ women reporting recent malarial infection was observed in one study. Given the public health impact of synergistic interactions between malaria and helminthic infections in HIV/HPV co-infected women on HAART, it is urgent that these interactions are elucidated.

Morbidity and nutrition status of rural drug-naïve Kenyan women living with HIV

This paper describes morbidity in a group of HIV-positive drug-naïve rural women in western Kenya. A total of 226 drug-naïve HIV-positive women were evaluated for baseline morbidity, immune function, and anthropometry before a food-based nutrition intervention. Kenyan nurses visited women in their homes and conducted semi-structured interviews regarding symptoms and physical signs experienced at the time of the visit and during the previous week and physical inspection. Blood and urine samples were examined for determination of immune function (CD4, CD8, and total lymphocyte counts), anaemia, malaria, and pregnancy status. Intradermal skin testing with tuberculin (PPD), candida, and tetanus toxoid antigens was also performed to evaluate cell-mediated immunity. Anthropometry was measured, and body mass index (BMI) was calculated. Seventy-six per cent of the women reported being sick on the day of the interview or within the previous week. Illnesses considered serious were reported by 13.7% of women. The most frequent morbidity episodes reported were upper respiratory tract infections (13.3%), suspected malaria (5.85%), skeletal pain (4.87%), and stomach pain (4.42%). The most common morbidity signs on physical inspection were respiratory symptoms, most commonly rhinorrhea and coughing. Confirmed malaria and severe diarrhea were significantly associated with a higher BMI.

Frequency and distribution patterns of opportunistic infections associated with HIV/AIDS in Uganda

Background

We conducted a study to assess the frequency and distribution patterns of selected opportunistic infections (OIs) and opportunistic cancers (OCs) in different geographical areas before and after HAART in Uganda.

Methods

This was a cross-sectional serial review of observation data for adult HIV positive patients (≥15 years) enrolled with the AIDS support organization (TASO) in Uganda covering the period from January 2001 to December 2013. Both AIDS defining OIs/OCs and non-AIDS defining OIs were analyzed. The study period was structured into three time periods: “pre- HAART” (2001–2003), “early-HAART” (2004–2008) and “late-HAART” (2009–2013). Descriptive statistics were used to summarize the data by time period, age, gender and geographical location. Chi squared test used to test the significance of the differences in proportions.

Results

A total of 108,619 HIV positive patients were included in the analysis. 64% (64,240) were female with median age of 33 years (IQR 27–40). The most frequent OIs before HAART were oral candida (34.6%) diarrhoeal infection (<1 month) (30.6%), geohelminths (26.5%), Mycobacterium tuberculosis (TB) (17.7%), malaria (15.1%) and bacterial pneumonia (11.2%). In early HAART (2004–2008), the most frequent OIs were geohelminths (32.4%), diarrhoeal infection (25.6%), TB (18.2%) and oral candida (18.1%). In late HAART (2009–2013), the most frequent OIs were geohelminths (23.5%) and diarrhoeal infection (14.3%). By gender, prevalence was consistently higher in women (p < 0.05) before and after HAART for geohelminths, candidiasis, diarrhoeal infection, bacterial pneumonia and genital ulcer disease but consistently higher in men for TB and Kaposi’s sarcoma (p < 0.05). By age, prevalence was consistently higher in older age groups (>30 years) before and after HAART for oral candida and TB (p < 0.05) and higher in young age groups (<30 years) for malaria and genital ulcers (p < 0.05). By geographical location, prevalence was consistently higher in Eastern and Northern Uganda before and after HAART for diarrheal infection and geohelminths (p < 0.0001).

Conclusions

The frequency and pattern of OIs before and after HAART differs by gender, age and geographical location. Prevalence of geohelminths and diarrhea infection(<1 month) remains high especially in Northern and Eastern Uganda even after HAART and should therefore be given special attention in HIV/AIDS care programmes in these settings.

Burden of malaria among adult patients attending general medical outpatient department and HIV care and treatment clinics in Oromia, Ethiopia: a comparative cross-sectional study

Background

Malaria and HIV/AIDS constitute major public health problems in Ethiopia, but the burden associated with malaria-HIV co-infection has not been well documented. In this study, the burden of malaria among HIV positive and HIV negative adult outpatients attending health facilities in Oromia National Regional State, Ethiopia was investigated.

Methods

A comparative cross-sectional study among HIV-positive patients having routine follow-up visits at HIV care and treatment clinics and HIV-seronegative patients attending the general medical outpatient departments in 12 health facilities during the peak malaria transmission season was conducted from September to November, 2011. A total of 3638 patients (1819 from each group) were enrolled in the study. Provider initiated testing and counseling of HIV was performed for 1831 medical outpatients out of whom 1819 were negative and enrolled into the study. Malaria blood microscopy and hemoglobin testing were performed for all 3638 patients. Data was analyzed using descriptive statistics, Chi square test and multivariate logistic regression.

Results

Of the 3638 patients enrolled in the study, malaria parasitaemia was detected in 156 (4.3 %); malaria parasitaemia prevalence was 0.7 % (13/1819) among HIV-seropositive patients and 7.9 % (143/1819) among HIV-seronegative patients. Among HIV-seropositive individuals 65.4 % slept under a mosquito bed net the night before data collection, compared to 59.4 % of HIV-seronegative individuals. A significantly higher proportion of HIV-seropositive malaria-negative patients were on co-trimoxazole (CTX) prophylaxis as compared to HIV-malaria co-infected patients: 82 % (1481/1806) versus 46 % (6/13) (P = 0.001). HIV and malaria co-infected patients were less likely to have the classical symptoms of malaria (fever, chills and headache) compared to the HIV-seronegative and malaria positive counterparts. Multivariate logistic regression showed that HIV-seropositive patients who come for routine follow up were less likely to be infected by malaria (OR = 0.23, 95 % CI = 0.09–0.74).

Conclusion

The study documented lower malaria prevalence among the HIV-seropositive attendants who come for routine follow up. Clinical symptoms of malaria were more pronounced among HIV-seronegative than HIV-seropositive patients. This study also re-affirmed the importance of co-trimoxazole in preventing malaria symptoms and parasitaemia among HIV- positive patients.

An In Vitro Model for Measuring Immune Responses to Malaria in the Context of HIV Co-infection

Malaria and HIV co-infection is a growing health priority. However, most research on malaria or HIV currently focuses on each infection individually. Although understanding the disease dynamics for each of these pathogens independently is vital, it is also important that the interactions between these pathogens are investigated and understood. We have developed a versatile in vitro model of HIV-malaria co-infection to study host immune responses to malaria in the context of HIV infection. Our model allows the study of secreted factors in cellular supernatants, cell surface and intracellular protein markers, as well as RNA expression levels. The experimental design and methods used limit variability and promote data reliability and reproducibility. All pathogens used in this model are natural human pathogens (Plasmodium falciparum and HIV-1), and all infected cells are naturally infected and used fresh. We use human erythrocytes parasitized with P. falciparum and maintained in continuous in vitro culture. We obtain freshly isolated peripheral blood mononuclear cells from chronically HIV-infected volunteers. Every condition used has an appropriate control (P. falciparum parasitized vs. normal erythrocytes), and every HIV-infected donor has an HIV uninfected control, from which cells are harvested on the same day. This model provides a realistic environment to study the interactions between malaria parasites and human immune cells in the context of HIV infection.

Evolution of the global burden of viral infections from unsafe medical injections, 2000-2010

Background

In 2000, the World Health Organization estimated that, in developing and transitional countries, unsafe injections accounted for respectively 5%, 32% and 40% of new infections with HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV). Safe injection campaigns were organized worldwide. The present study sought to measure the progress in reducing the transmission of these viruses through unsafe injections over the subsequent decade.

Methods

A mass action model was updated, to recalculate the number of injection-related HIV, HCV and HBV infections acquired in 2000 and provide estimates for 2010. Data about the annual number of unsafe injections were updated. HIV prevalence in various regions in 2000 and 2010 were calculated from UNAIDS data. The ratio of HIV prevalence in healthcare settings compared to the general population was estimated from a literature review. Improved regional estimates of the prevalence of HCV seropositivity, HBsAg and HBeAg antigenemia were used for 2000 and 2010. For HIV and HCV, revised estimates of the probability of transmission per episode of unsafe injection were used, with low and high values allowing sensitivity analyses.

Results

Despite a 13% population growth, there was a reduction of respectively 87% and 83% in the absolute numbers of HIV and HCV infections transmitted through injections. For HBV, the reduction was more marked (91%) due to the additional impact of vaccination. While injections-related cases had accounted for 4.6%–9.1% of newly acquired HIV infections in 2000, this proportion decreased to 0.7%–1.3% in 2010, when unsafe injections caused between 16,939 and 33,877 HIV infections, between 157,592 and 315,120 HCV infections, and 1,679,745 HBV infections.

Conclusion

From 2000 to 2010, substantial progress was made in reducing the burden of HIV, HCV and HBV infections transmitted through injections. In some regions, their elimination might become a reasonable public health goal.

Outcome of artemether-lumefantrine treatment for uncomplicated malaria in HIV-infected adult patients on anti-retroviral therapy

BACKGROUND

Malaria and HIV infections are both highly prevalent in sub-Saharan Africa, with HIV-infected patients being at higher risks of acquiring malaria. The majority of antiretroviral (ART) and anti-malarial drugs are metabolized by the CYP450 system, creating a chance of drug-drug interaction upon co-administration. Limited data are available on the effectiveness of the artemether-lumefantrine combination (AL) when co-administered with non-nucleoside reverse transcriptase inhibitors (NNRTIs). The aim of this study was to compare anti-malarial treatment responses between HIV-1 infected patients on either nevirapine- or efavirenz-based treatment and those not yet on ART (control-arm) with uncomplicated falciparum malaria, treated with AL.

METHOD

This was a prospective, non-randomized, open-label study conducted in Bagamoyo district, with three arms of HIV-infected adults: efavirenz-based treatment arm (EFV-arm) n = 66, nevirapine-based treatment arm (NVP-arm) n = 128, and control-arm n = 75, with uncomplicated malaria. All patients were treated with AL and followed up for 28 days. The primary outcome measure was an adequate clinical and parasitological response (ACPR) after treatment with AL by day 28.

RESULTS

Day 28 ACPR was 97.6%, 82.5% and 94.5% for the NVP-arm, EFV-arm and control-arm, respectively. No early treatment or late parasitological failure was reported. The cumulative risk of recurrent parasitaemia was >19-fold higher in the EFV-arm than in the control-arm (Hazard ratio [HR], 19.11 [95% confidence interval {CI}, 10.5-34.5]; P < 0.01). The cumulative risk of recurrent parasitaemia in the NVP-arm was not significantly higher than in the control-arm ([HR], 2.44 [95% {CI}, 0.79-7.6]; P = 0.53). The median (IQR) day 7 plasma concentrations of lumefantrine for the three arms were: 1,125 ng/m (638.8-1913), 300.4 ng/ml (220.8-343.1) and 970 ng/ml (562.1-1729) for the NVP-arm, the EFV-arm and the control-arm, respectively (P < 0.001). In all three arms, the reported adverse events were mostly mild.

CONCLUSION

After 28 days of follow-up, AL was statistically safe and effective in the treatment of uncomplicated malaria in the NVP-arm. The results of this study also provide an indication of the possible impact of EFV on the performance of AL and the likelihood of it affecting uncomplicated falciparum malaria treatment outcome.

Can plant biotechnology help break the HIV-malaria link?

The population of sub-Saharan Africa is at risk from multiple, poverty-related endemic diseases. HIV and malaria are the most prevalent, but they disproportionately affect different groups of people, i.e. HIV predominantly affects sexually-active adults whereas malaria has a greater impact on children and pregnant women. Nevertheless, there is a significant geographical and epidemiological overlap which results in bidirectional and synergistic interactions with important consequences for public health. The immunosuppressive effects of HIV increase the risk of infection when individuals are exposed to malaria parasites and also the severity of malaria symptoms. Similarly, acute malaria can induce a temporary increase in the HIV viral load. HIV is associated with a wide range of opportunistic infections that can be misdiagnosed as malaria, resulting in the wasteful misuse of antimalarial drugs and a failure to address the genuine cause of the disease. There is also a cumulative risk of toxicity when antiretroviral and antimalarial drugs are given to the same patients. Synergistic approaches involving the control of malaria as a strategy to fight HIV/AIDS and vice versa are therefore needed in co-endemic areas. Plant biotechnology has emerged as a promising approach to tackle poverty-related diseases because plant-derived drugs and vaccines can be produced inexpensively in developing countries and may be distributed using agricultural infrastructure without the need for a cold chain. Here we explore some of the potential contributions of plant biotechnology and its integration into broader multidisciplinary public health programs to combat the two diseases in developing countries.

Increased severity and mortality in adults co-infected with malaria and HIV in Maputo, Mozambique: a prospective cross-sectional study

Background

Co-infection with falciparum malaria and HIV-1 increases the severity and mortality of both infections in unstable malaria-transmission areas. In contrast, in stable transmission areas, HIV co-infection increases the severity of both infections but has not been found to influence malaria mortality.

Methods

In a prospective cross-sectional study, clinical and laboratory data were consecutively collected for all adults admitted with fever and/or suspected malaria to the medical department of the Central Hospital of Maputo, Mozambique, during two malaria seasons from January 2011. Malaria and HIV PCRs were performed, and risk factors for fatal outcomes were analysed. The impact of HIV on the clinical presentation and mortality of malaria was assessed.

Findings

A total of 212 non-pregnant adults with fever and/or suspected malaria and 56 healthy controls were included in the study. Of the 131 patients with confirmed falciparum malaria, 70 were co-infected with HIV-1. The in-hospital mortality of the co-infected patients was 13.0% (9/69) compared with 1.7% (1/59) in the patients without HIV (p = 0.018). Malaria severity (p = 0.016) and co-infection with HIV (p = 0.064) were independent risk factors for death although the association with HIV did not reach statistical significance. The co-infected patients had significantly more frequent respiratory distress, bleeding disturbances, hypoglycaemia, liver and renal failure and high malaria parasitemia compared with the patients with malaria alone.

Interpretations

HIV co-infection is associated with increased disease severity in and mortality from malaria in an area of stable malaria transmission. This finding was not observed earlier and should motivate doctors working in malaria-endemic areas to consider early HIV testing and a closer follow-up of patients with malaria and HIV co-infection.

Malaria is an uncommon cause of adult sepsis in south-western Uganda

Background

Malaria is often considered a cause of adult sepsis in malaria endemic areas. However, diagnostic limitations can make distinction between malaria and other infections challenging. Therefore, the objective of this study was to determine the relative contribution of malaria to adult sepsis in south-western Uganda.

Methods

Adult patients with sepsis were enrolled at the Mbarara Regional Referral Hospital between February and May 2012. Sepsis was defined as infection plus ≥2 of the following: axillary temperature >37.5°C or <35.5°C, heart rate >90 or respiratory rate >20. Severe sepsis was defined as sepsis plus organ dysfunction (blood lactate >4 mmol/L, confusion, or a systolic blood pressure <90 mmHg). Sociodemographic, clinical and laboratory data, including malaria PCR and rapid diagnostic tests, as well as acid fast bacteria sputum smears and blood cultures were collected. Patients were followed until in-patient death or discharge. The primary outcome of interest was the cause of sepsis. Multivariable logistic regression was performed to assess predictors of mortality.

Results

Enrollment included 216 participants who were 51% female with a median age of 32 years (IQR 27–43 years). Of these, 122 (56%) subjects were HIV-seropositive of whom 75 (66%) had a CD4+ T cell count <100 cells/μL. The prevalence of malaria was 4% (six with Plasmodium falciparum, two with Plasmodium vivax). Bacteraemia was identified in 41 (19%) patients. In-hospital mortality was 19% (n = 42). In multivariable regression analysis, Glasgow Coma Score <9 (IRR 4.81, 95% CI 1.80-12.8) and severe sepsis (IRR, 2.07, 95% CI 1.03-4.14), but no specific diagnoses were statistically associated with in-hospital mortality.

Conclusion

Malaria was an uncommon cause of adult sepsis in a regional referral hospital in south-western Uganda. In this setting, a thorough evaluation for alternate causes of disease in patients presenting with sepsis is recommended.

HIV infection deregulates innate immunity to malaria despite combination antiretroviral therapy

OBJECTIVE

Malaria and HIV-1 adversely interact, with HIV-positive individuals suffering higher parasite burdens and worse clinical outcomes. However, the mechanisms underlying these disease interactions are unclear. We hypothesized that HIV coinfection impairs the innate immune response to malaria, and that combination antiretroviral therapy (cART) may restore this response. Our aim was to examine the innate inflammatory response of natural killer (NK), natural killer T (NKT), and γδ T-cells isolated from the peripheral blood of HIV-infected therapy-naive donors to malaria parasites, and determine the effect of cART on these responses.

METHODS

Freshly isolated peripheral blood mononuclear cells from 25 HIV-infected individuals pre-cART (month 0) and post-cART (months 3 and 6), and HIV-negative individuals at matched time-points, were cultured in the presence of Plasmodium falciparum parasitized erythrocytes. Supernatants and cells were collected to assess cytokine production and phenotypic changes.

RESULTS

Compared to HIV-negative participants, NKT, NK, and γδ T-cell subsets from participants with chronic HIV infection showed marked differences, including decreased production of interferon γ (IFNγ) and tumor necrosis factor (TNF) in response to malaria parasites. IFNγ production was linked to interleukin-18 receptor (IL-18R) expression in all three cell types studied. Six months of cART provided partial cellular reconstitution but had no effect on IL-18R expression, or IFNγ and TNF production.

CONCLUSION

These data suggest that HIV infection impairs the inflammatory response of innate effector cells to malaria, and that the response is not fully restored within 6 months of cART. This may contribute to higher parasite burdens and ineffective immune responses, and have implications for vaccination initiatives in coinfected individuals.

Effect of malaria on HIV/AIDS transmission and progression

Malaria and HIV are among the two most important global health problems of developing countries. They cause more than 4 million deaths a year. These two infections interact bidirectionally and synergistically with each other. HIV infection increases the risk of an increase in the severity of malaria infection and burdens of malaria, which in turn facilitates the rate of malaria transmission. Malaria infection is also associated with strong CD4+ cell activation and up-regulation of proinflammatory cytokines and it provides an ideal microenvironment for the spread of the virus among the CD4+ cells and for rapid HIV-1 replication. Additionally, malaria increases blood viral burden by different mechanisms. Therefore, high concentrations of HIV-1 RNA in the blood are predictive of disease progression, and correlate with the risk of blood-borne, vertical, and sexual transmission of the virus. Therefore, this article aims to review information about HIV malaria interactions, the effect of malaria on HIV transmission and progression and the implications related to prevention and treatment of coinfection.

Antimalaria action of antiretroviral drugs on Plasmodium berghei in mice

Malaria parasitemia enhances replication of human immunodeficiency virus. Antiretroviral drugs that possess antiplasmodial activity may reverse such an effect. Activity of the antiretroviral drugs lamivudine (L), zidovudine (Z), nevirapine (N), and stavudine (S) against Plasmodium berghei inoculated into 70 adult albino mice was investigated. Eight groups of five animals each were treated with different drugs as either curative or prophylactic regimens. These regimens were also given to four groups as L/Z/N or L/S/N. Z therapy alone and L/Z/N eliminated malaria parasites as follows: curative and prophylactic Z groups, mean ± SEM = 62,132.87 ± 22,816.1 parasites/μL and 62,474.85 ± 14,639.1 parasites/μL, respectively on day 4 and 0 parasites/μL on day 26; curative L/Z/N group, 31,583.53 ± 6,361.67 parasites/μL, and 0 parasites/μL (days 4 and 18, respectively); prophylactic L/Z/N group, 41,138.1 ± 3,528.03 parasites/μL, and 0 parasites/μL (days 4, and 20 respectively). Peters four-day suppressive values were 67-82.2%. Zidovudine or L/Z/N therapy may modify the epidemiology of malaria and therefore the pandemic of human immunodeficiency virus infection.

The effect of HIV on malaria in the context of the current standard of care for HIV-infected populations in Africa

HIV infection affects the clinical pattern of malaria. There is emerging evidence to suggest that previously documented interactions may be modified by recently scaled-up HIV and malaria interventions. Prophylaxis with trimethoprim-sulfamethoxazole (TS) in combination with use of insecticide-treated nets can markedly decrease the incidence of malaria in HIV-infected pregnant and nonpregnant adults and children even in the setting of antifolate resistance-conferring mutations that are currently common in Africa. Nonetheless, additional interventions are needed to protect HIV-infected people that reside in high-malaria-transmission areas. Artemether-lumefantrine and dihydroartemisinin-piperaquine are highly efficacious and safe for the treatment of uncomplicated malaria in HIV-infected persons. Coadministration of antiretroviral and antimalarial drugs creates the potential for pharmacokinetic drug interactions that may increase (causing enhancement of malaria treatment efficacy and post-treatment prophylaxis and/or unanticipated toxicity) or reduce (creating risk for treatment failure) antimalarial drug exposure. Further studies are needed to elucidate potentially important pharmacokinetic interactions between commonly used antimalarials, antiretrovirals and TS and their clinical implications. Data on the benefits of long-term TS prophylaxis among HIV patients on antiretroviral therapy who have achieved immune-reconstitution are limited. Studies to address these questions are ongoing or planned, and the results should provide the evidence base required to guide the prevention and treatment of malaria in HIV-infected patients.

The Impact of HIV Coinfection on Cerebral Malaria Pathogenesis

HIV infection is widespread throughout the world and is especially prevalent in sub-Saharan Africa and Asia. Similarly, Plasmodium falciparum, the most common cause of severe malaria, affects large areas of sub-Saharan Africa, the Indian subcontinent, and Southeast Asia. Although initial studies suggested that HIV and malaria had independent impact upon patient outcomes, recent studies have indicated a more significant interaction. Clinical studies have shown that people infected with HIV have more frequent and severe episodes of malaria, and parameters of HIV disease progression worsen in individuals during acute malaria episodes. However, the effect of HIV on development of cerebral malaria, a manifestation of P. falciparum infection that is frequently fatal, has not been characterized. We review clinical and basic science studies pertaining to HIV and malaria coinfection and cerebral malaria in particular in order to highlight the likely role HIV plays in exacerbating cerebral malaria pathogenesis.

Consequences of HIV infection on malaria and therapeutic implications: a systematic review

Despite recent changes in the epidemiology of HIV infection and malaria and major improvements in their control, these diseases remain two of the most important infectious diseases and global health priorities. As they have overlapping distribution in tropical areas, particularly sub-Saharan Africa, any of their clinical, diagnostic, and therapeutic interactions might have important effects on patient care and public health policy. The biological basis of these interactions is well established. HIV infection induces cellular depletion and early abnormalities of CD4+ T cells, decreases CD8+ T-cell counts and function (cellular immunity), causes deterioration of specific antigen responses (humoral immunity), and leads to alteration of innate immunity through impairment of cytolytic activity and cytokine production by natural killer cells. Therefore, HIV infection affects the immune response to malaria, particularly premunition in adolescents and adults, and pregnancy-specific immunity, leading to different patterns of disease in HIV-infected patients compared with HIV-uninfected patients. In this systematic review, we collate data on the effects of HIV on malaria and discuss their therapeutic consequences. HIV infection is associated with increased prevalence and severity of clinical malaria and impaired response to antimalarial treatment, depending on age, immunodepression, and previous immunity to malaria. HIV also affects pregnancy-specific immunity to malaria and response to intermittent preventive treatment. Co-trimoxazole (trimethoprim-sulfamethoxazole) prophylaxis and antiretroviral treatment reduce occurrence of clinical malaria; however, these therapies interact with antimalarial drugs, and new therapeutic guidelines are needed for concomitant use.

Cardiac Conduction Safety during Coadministration of Artemether-Lumefantrine and Lopinavir/Ritonavir in HIV-Infected Ugandan Adults

Background. We aimed to assess cardiac conduction safety of coadministration of the CYP3A4 inhibitor lopinavir/ritonavir (LPV/r) and the CYP3A4 substrate artemether-lumefantrine (AL) in HIV-positive Ugandans. Methods. Open-label safety study of HIV-positive adults administered single-dose AL (80/400 mg) alone or with LPV/r (400/100 mg). Cardiac function was monitored using continuous electrocardiograph (ECG). Results. Thirty-two patients were enrolled; 16 taking LPV/r -based ART and 16 ART naïve. All took single dose AL. No serious adverse events were observed. ECG parameters in milliseconds remained within normal limits. QTc measurements did not change significantly over 72 hours although were higher in LPV/r arm at 24 (424 versus 406; P = .02) and 72 hours (424 versus 408; P = .004) after AL intake. Conclusion. Coadministration of single dose of AL with LPV/r was safe; however, safety of six-dose AL regimen with LPV/r should be investigated.

Effect of HIV infection on the acute antibody response to malaria antigens in children: an observational study

Background

In sub-Saharan Africa, the distributions of malaria and HIV widely overlap. Among pregnant and non-pregnant adults, HIV affects susceptibility to malaria, its clinical course and impairs antibody responses to malaria antigens. However, the relationship between the two diseases in childhood, when most deaths from malaria occur, is less clear. It was previously reported that HIV is associated with admission to hospital in rural Kenya with severe malaria among children, except in infancy. HIV-infected children with severe malaria were older, had higher parasite density and increased mortality, raising a hypothesis that HIV interferes with naturally acquired immunity to malaria, hence with little effect at younger ages (a shorter history of exposure). To test this hypothesis, levels of anti-merozoite and schizont extract antibodies were compared between HIV-infected and uninfected children who participated in the original study.

Methods

IgG responses to malaria antigens that are potential targets for immunity to malaria (AMA1, MSP2, MSP3 and schizont extract) were compared between 115 HIV-infected and 115 age-matched, HIV-uninfected children who presented with severe malaria. The children were classified as high and low responders for each antigen and assigned antibody-response breadth scores according to the number of antigens to which they were responsive. A predictive logistic regression model was used to test if HIV was an effect modifier on the age-related acquisition of antibody responses, with age as a continuous variable.

Results

Point estimates of the responses to all antigens were lower amongst HIV-infected children, but this was only statistically significant for AMA1 (P = 0.028). HIV-infected children were less likely to be high responders to AMA1 [OR 0.44 (95%CI, 0.2-0.90) P = 0.024]. HIV was associated with a reduced breadth of responses to individual merozoite antigens (P = 0.02). HIV strongly modified the acquisition of antibodies against schizont extract with increasing age (P < 0.0001), but did not modify the rate of age-related acquisition of responses to individual merozoite antigens.

Conclusions

In children with severe malaria, HIV infection is associated with a lower magnitude and narrower breadth of IgG responses to merozoite antigens and stunting of age-related acquisition of the IgG antibody response to schizont extract.

The Interaction between HIV and malaria in Africa

HIV and malaria kill millions of people every year. They share a common geographic distribution, and both cause far more disease and death in sub-Saharan Africa than they do in the rest of the world. Many epidemiologic studies have suggested that HIV and malaria coexist independently, but some recent reports describe synergistic interactions between them. People living with HIV infection who do not have pre-existing immunity to malaria experience a marked increase in malaria severity. But for those who have acquired immunity through natural exposure to malaria, HIV-related immunosuppression is associated with only a modest increase in clinical malaria, which may be explained in part by more frequent nonmalaria febrile episodes. The effect of malaria infection on HIV disease progression due to increased viral replication may be important but has not yet been fully explored.

An intra-host mathematical model on interaction between HIV and malaria

In this paper a mathematical model is proposed for the interaction of the immune system with HIV viruses and malaria parasites in an individual host. It consists of a system of three coupled ordinary differential equations, which represents the rate of change in the concentration of malaria parasites, HIV viruses and immunity effector within a host, respectively. The theoretical model gives insight into the biological balance between pathogen replication and the immune response to the pathogen: persistence versus elimination of the pathogen, which determines the outcome of infection. Dynamical analysis shows that the outcomes of the interactions between the immune system of the host with either malaria parasites or HIV viruses are dramatic such as malaria infection promoting proliferation of HIV virus, HIV infection increasing the risk from malaria and the immune system of the host failing to keep the diseases under control, etc. The results provide a new perspective for understanding of the complexity mechanisms of the co-infection (or dual infection) with malaria and HIV in a host.

Effects of trimethoprim-sulfamethoxazole and insecticide-treated bednets on malaria among HIV-infected Ugandan children

BACKGROUND

Trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis and insecticide-treated bednets reduce malaria risk among HIV-infected adults. The efficacy of TMP/SMX may be diminished where antifolate resistance to malaria is high. We evaluated the efficacy of these interventions for malaria prevention among Ugandan children.

METHODS

We concurrently followed 300 HIV-infected children aged 1-10 years and a community-based cohort of 561 healthy children aged 1-11 years over 11 months in Kampala, Uganda. The HIV-infected children received TMP/SMX prophylaxis and insecticide treated bednets. In the community cohort, insecticide-treated bednets were introduced during the observation period. Children from both cohorts were followed using a standardized protocol to measure the incidence of malaria.

RESULTS

Only nine episodes of malaria were diagnosed among HIV-infected children (incidence = 0.07/person-year) in comparison with 440 episodes among children from the community (incidence = 0.90/person-year; P < 0.0001). The use of insecticide-treated bednets was associated with a 43% reduction in malaria incidence (P < 0.001), and a combination of TMP/SMX and use of insecticide-treated bednets with a 97% reduction in malaria incidence (P < 0.001). The prevalence of five mutations associated with antifolate resistance was high among malaria cases detected in both the HIV (100%) and community cohorts (75%). Malaria accounted for only 4% of febrile episodes in the HIV cohort in comparison with 33% in the community-based cohort (P < 0.0001).

CONCLUSION

In a malaria endemic area with a high level of molecular markers of antifolate resistance, the combined use of TMP/SMX prophylaxis and insecticide-treated bednets was associated with a dramatic reduction in malaria incidence among HIV-infected children.

Effect of HIV-1 infection on malaria treatment outcome in Ugandan patients

BACKGROUND

Malaria and HIV-1 infection cause significant morbidity and mortality in sub-Saharan Africa. HIV-1 increases risk for malaria with the risk increasing as immunity declines. The effect of HIV-1 infection on antimalarial treatment outcome is still inconclusive.

OBJECTIVE

To compare antimalarial treatment outcome among HIV-1 positive and negative patients with acute uncomplicated falciparum malaria treated with chloroquine plus sulfadoxine-pyrimethamine (CQ+SP).

METHODS

Ninety eight HIV-1 positive patients aged 18 months or older with acute uncomplicated falciparum malaria were treated with CQ+SP and followed for 28 days to monitor outcome. Treatment outcome of HIV-1 positive patients was compared to that of 193 HIV-1 negative historical controls. The primary study outcome for both groups was treatment failure.

RESULTS

HIV-1 positive patients older than 5 years of age were less likely to have treatment failure compared to HIV-1 negative patients in the same age group (RR 0.59 95% CI 0.4-0.8, p < 0.001) and HIV-1 positive patients on routine cotrimoxazole prophylaxis were less likely to have treatment failure following CQ+SP treatment compared to HIV negative patients (RR 0.6 95% CI 0.43-0.92, p = 0.006). There was no difference in treatment outcome according to HIV-1 status for children younger than 5 years of age.

CONCLUSIONS

Adherence to cotrimoxazole prophylaxis should be reinforced in HIV positive patients and it should be reassessed if these patients present with acute episodes of malaria.

Effect of co-trimoxazole prophylaxis, antiretroviral therapy, and insecticide-treated bednets on the frequency of malaria in HIV-1-infected adults in Uganda: a prospective cohort study

BACKGROUND

HIV-1 and malaria are common infections in Africa, and cause substantial morbidity and mortality. HIV infection has been associated with an increased incidence of malaria, and more severe disease. Our aim was to assess the effect of antiretroviral treatment (ART) on the frequency of clinical malaria in people with HIV, and to measure the additive effects of co-trimoxazole (trimethoprim and sulfamethoxazole) prophylaxis, ART, and insecticide-treated bednets.

METHODS

In 2001, we enrolled 466 HIV-infected individuals aged 18 years or older in Uganda in a prospective cohort study that provided co-trimoxazole prophylaxis to 399 participants after 5 months of no intervention. In 2003, we enrolled 138 survivors from the initial study, and 897 new participants from the same community, to take antiretroviral therapy (ART) in addition to co-trimoxazole prophylaxis. The ART was in most cases a combination of stavudine, lamivudine, and nevirapine or efavirenz. In 2004, we also gave participants insecticide-treated bednets. Households were visited weekly by study staff to record fever, illness, or death in the preceding 7 days. In cases of reported fever in the previous 2 days, we took blood to test for malaria parasites. We compared the frequency of clinical malaria, adjusting for CD4-cell count, age, sex, and season.

FINDINGS

1035 individuals were given co-trimoxazole and ART (median age 38 years, 74% female, and median CD4-cell count 124 cells/microL); 985 of these, plus four new participants, received co-trimoxazole, ART, and bednets. There were 166 cases of clinical malaria in the study. Compared with a baseline malaria incidence of 50.8 episodes per 100 person-years, co-trimoxazole prophylaxis was associated with 9.0 episodes per 100 person-years (adjusted incidence rate ratio [IRR] 0.24, 95% CI 0.15-0.38); ART and co-trimoxazole with 3.5 episodes per 100 person-years (0.08, 0.04-0.17); and co-trimoxazole, ART, and bednets with 2.1 episodes per 100 person-years (0.05, 0.03-0.08). Malaria incidence was significantly lower during ART and co-trimoxazole than during co-trimoxazole alone (IRR 0.36 [95% CI 0.18-0.74], p=0.0056).

INTERPRETATION

A combination of co-trimoxazole, antiretroviral therapy, and insecticide-treated bednets substantially reduced the frequency of malaria in adults with HIV.

Increased severe anemia in HIV-1-exposed and HIV-1-positive infants and children during acute malaria

OBJECTIVE

Since the primary hematological complication in both pediatric HIV-1 and malaria is anemia, co-infection with these pathogens may promote life-threatening severe malarial anemia (SMA). The primary objective of the study was to determine if HIV-1 exposure [HIV-1(exp)] and/or HIV-1 infection [HIV-1(+)] increased the prevalence of SMA in children with acute malaria.

DESIGN

The effect of HIV-1 exposure and HIV-1 infection on the prevalence of SMA (hemoglobin < 6.0 g/dl), parasitemia (parasites/microl), and high-density parasitemia (HDP, >or= 10 000 parasites/mul) was investigated in children <or= 2 years of age presenting at hospital with acute Plasmodium falciparum malaria in a rural holoendemic malaria transmission area of western Kenya.

METHODS

Upon enrollment, a complete hematological and clinical evaluation was performed on all children. Malaria parasitemia was determined and children with acute P. falciparum malaria were evaluated for HIV-1 exposure and infection by two rapid serological antibody tests and HIV-1 DNA PCR, respectively.

RESULTS

Relative to HIV-1(-) group (n = 194), the HIV-1(exp) (n = 100) and HIV-1(+) (n = 23) groups had lower hemoglobin concentrations (P < 0.001 and P < 0.001, respectively), while parasitemia and HDP were equivalent between the three groups. Multivariate analyses demonstrated that the risk of SMA was elevated in HIV-1(exp) children (odds ratio, 2.17; 95% confidence interval, 1.25-3.78; P < 0.01) and HIV-1(+) children (odds ratio, 8.71; 95% confidence interval, 3.37-22.51; P < 0.0001). The multivariate model further revealed that HIV-1 exposure or infection were not significantly associated with HDP.

CONCLUSIONS

Results presented here demonstrate that both HIV-1 exposure and HIV-1 infection are associated with increased prevalence of SMA during acute P. falciparum infection, independent of parasite density.

Parasitic central nervous system infections in immunocompromised hosts: malaria, microsporidiosis, leishmaniasis, and African trypanosomiasis

Immunosuppression associated with HIV infection or following transplantation increases susceptibility to central nervous system (CNS) infections. Because of increasing international travel, parasites that were previously limited to tropical regions pose an increasing infectious threat to populations at risk for acquiring opportunistic infection, especially people with HIV infection or individuals who have received a solid organ or bone marrow transplant. Although long-term immunosuppression caused by medications such as prednisone likely also increases the risk for acquiring infection and for developing CNS manifestations, little published information is available to support this hypothesis. In an earlier article published in Clinical Infectious Diseases, we described the neurologic manifestations of some of the more common parasitic CNS infections. This review will discuss the presentation, diagnosis, and treatment of the following additional parasitic CNS infections: malaria, microsporidiosis, leishmaniasis, and African trypanosomiasis.

Stage-specific effects of Plasmodium falciparum-derived hemozoin on blood mononuclear cell TNF-alpha regulation and viral replication

BACKGROUND

The molecular immunological interactions between HIV and malaria are largely undefined. Since tumor necrosis factor (TNF)-alpha is elevated during acute malaria and increases with HIV-1 disease progression, TNF-alpha production may be an important mediator for interactions between malaria and HIV-1.

METHODS

To examine the stage-specific immunological interactions between HIV and malaria, peripheral blood mononuclear cells (PBMC) and CD14 cells were isolated and cultured from rhesus macaques at different stages of SIV infection. Cultures were stimulated with lipopolysaccharide (LPS) and interferon (IFN)-gamma in the presence of Plasmodium falciparum-derived hemozoin (Hz) or synthetic Hz (sHz). TNF-alpha transcripts and soluble protein were examined by real time reverse transcription-PCR and ELISA, respectively. The effects of Hz on viral replication were determined by measurement of p27 antigen with varying concentrations of TNF-alpha neutralizing antibodies.

RESULTS

Hz and sHz significantly increased LPS- and IFN-gamma-induced TNF-alpha protein and transcripts in PBMC from animals with late stage SIV infection (i.e., AIDS). Hz and sHz also induced high levels of sustained TNF-alpha transcripts in PBMC from the AIDS group. During the late stage of disease, CD14 cells were the primary source of TNF-alpha production. Stimulation of PBMC with Hz and sHz significantly increased viral replication that was dose-dependently reduced by the addition of TNF-alpha neutralizing antibodies.

CONCLUSIONS

Hz promotes high levels of TNF-alpha production from PBMC during AIDS and increases viral replication in SIV-infected animals.

Increased prevalence of severe malaria in HIV-infected adults in South Africa

BACKGROUND

Conflicting reports exist regarding the impact of human immunodeficiency virus (HIV) infection on the risk of severe malaria. We aimed to assess the effect of HIV infection status, advancing immunosuppression, and antimalarial immunity on the severity of malaria.

METHODS

A prospective cohort study was conducted. Consecutive hospitalized adult patients with falciparum malaria were tested for HIV antibodies and to determine CD4+ T cell count. Immunity to malaria was assessed by obtaining a history of childhood residence in an area where malaria is endemic. Patients were assessed for features of severe malaria.

RESULTS

Three hundred thirty-six patients were enrolled in the study, of whom 32 (10%) had severe malaria. The prevalence of HIV infection was 33%, and 111 patients (33%) were nonimmune to malaria. HIV-infected patients complained more frequently about respiratory and abdominal symptoms and less frequently about rigors and headache. Risk factors for severe malaria determined by multivariate analysis included being nonimmune to malaria, having a positive HIV serostatus, having an elevated parasite count, and having an increased white blood cell count. Risk of severe malaria was increased in HIV-infected patients with a CD4+ T cell count of < 200 x 10(6) cells/L (P < or = .001). Nonimmune HIV-infected patients were significantly more likely to have severe malaria (13 [36%] of 36 patients) than were nonimmune non-HIV-infected patients (9 [12%] of 75 patients; odds ratio, 4.15 [95% confidence interval, 1.57-10.97]; P = .003). HIV serostatus did not affect risk of severe malaria in the group from an area with endemicity (5 [7%] of 74 HIV-infected patients had severe malaria, and 5 [3%] of 151 non-HIV-infected patients had malaria; P = .248).

CONCLUSIONS

HIV-infected nonimmune adults are at increased risk of severe malaria. This risk is associated with a low CD4+ T cell count. This interaction is of great public health importance.

Modulation of immune responses during HIV-malaria co-infection in pregnancy

Infection with either HIV or malaria during pregnancy often results in adverse outcomes for mother and child. Co-infection further increases the risks of these events, which include maternal anemia and babies with low birth weight. The immunological bases for the increased susceptibility of HIV-infected mothers to malaria and for the effect of co-infection on mother-to-child transmission of HIV are areas of major importance in public health. In this article, we review current data about humoral and cellular responses to HIV-placental-malaria co-infection and present an immunological hypothesis to explain the epidemiological findings.

Imported malaria in an HIV-positive traveler: a case report with a fatal outcome

We report a fatal case of malaria in an HIV-coinfected nonimmune traveler. The primary cause of death is discussed. The importance of prevention of malaria in nonimmune travelers is stressed. Prevention of malaria in nonimmune travelers should be regarded as a priority area for clinical practice and operational research.

Pharmacotherapy, vaccines and malaria advice for HIV-infected travellers

Since the introduction of effective antiretroviral therapy (ART), HIV-infected individuals are travelling more frequently and international travel has become much safer. Specific concerns include the safety of ART during travel, drug adherence and interaction considerations, and effects of immunosuppression. This review describes potentially important infections, vaccine effectiveness, safety and special approaches for their use, and HIV-related issues regarding predeparture counselling. With advanced immunosuppression (CD4+ T-cell count < 200/microl or < 14%), the immunogenicity of several vaccines is reduced, complications could occur after live attenuated vaccines and certain infections acquired during travel may be more frequent or severe. Challenges include the best options for malaria chemoprophylaxis, standby treatment and medical follow-up of the increasing number of HIV-infected long-term travellers.

T-cell depletion and immunity to malaria in HIV-infections

Although early reports on HIV and malaria in co-infected subjects indicated little apparent interaction between the two infections, more recent investigations have found evidence for HIV increasing the risk from malaria. Conversely, increased viral load in susceptible cells occurs in malaria-infected people. However, the overall pattern of results is still somewhat confusing and contradictory. While morbidity from malaria may be greater in HIV-positive patients and in several reports the mortality risk is also higher, major increases in blood-stage parasitaemias that one might expect are not generally observed. The results of surveys are summarized and discussed in the context of what is known of malaria and HIV immunology in the light of recent data from humans as well as animal models.

The effect of Plasmodium falciparum malaria on peripheral and placental HIV-1 RNA concentrations in pregnant Malawian women

OBJECTIVE

To investigate the effect of placental Plasmodium falciparum malaria infection on peripheral and/or placental HIV-1 viral load.

DESIGN

A cross-sectional study of HIV-infected pregnant women, with and without placental malaria, delivering at Queen Elizabeth Central Hospital in Malawi.

METHODS

Peripheral blood samples were collected from consenting women and tested for HIV. HIV-infected women received nevirapine at the onset of labor. At delivery, placental blood and tissue specimens were collected. HIV-1 RNA concentrations were measured in peripheral and placental plasma samples, and malaria infection was determined by placental histopathology.

RESULTS

Of the 480 HIV-infected women enrolled, 304 had placental histopathology performed, of whom 74 (24.3%) had placental malaria. Compared with women without placental malaria, those with placental malaria had a 2.5-fold higher geometric mean peripheral HIV-1 RNA concentration (62,359 versus 24 814 copies/ml; P = 0.0007) and a 2.4-fold higher geometric mean placental HIV-1 RNA concentration (11,733 versus 4919 copies/ml; P = 0.008). In multivariate analyses, after adjusting for CD4 cell count and other covariates, placental malaria was associated with a 1.7-fold increase in geometric mean peripheral HIV-1 RNA concentration (47,747 versus 27,317 copies/ml; P = 0.02) and a 2.0-fold increase in geometric mean placental HIV-1 RNA concentration (9670 versus 4874 copies/ml; P = 0.03).

CONCLUSION

Placental malaria infection is associated with an increase in peripheral and placental HIV-1 viral load, which might increase the risk of mother-to-child transmission of HIV.

Association between climate variability and malaria epidemics in the East African highlands

The causes of the recent reemergence of Plasmodium falciparum epidemic malaria in the East African highlands are controversial. Regional climate changes have been invoked as a major factor; however, assessing the impact of climate in malaria resurgence is difficult due to high spatial and temporal climate variability and the lack of long-term data series on malaria cases from different sites. Climate variability, defined as short-term fluctuations around the mean climate state, may be epidemiologically more relevant than mean temperature change, but its effects on malaria epidemics have not been rigorously examined. Here we used nonlinear mixed-regression model to investigate the association between autoregression (number of malaria outpatients during the previous time period), seasonality and climate variability, and the number of monthly malaria outpatients of the past 10-20 years in seven highland sites in East Africa. The model explained 65-81% of the variance in the number of monthly malaria outpatients. Nonlinear and synergistic effects of temperature and rainfall on the number of malaria outpatients were found in all seven sites. The net variance in the number of monthly malaria outpatients caused by autoregression and seasonality varied among sites and ranged from 18 to 63% (mean=38.6%), whereas 12-63% (mean=36.1%) of variance is attributed to climate variability. Our results suggest that there was a high spatial variation in the sensitivity of malaria outpatient number to climate fluctuations in the highlands, and that climate variability played an important role in initiating malaria epidemics in the East African highlands.

Maternal malaria and perinatal HIV transmission, western Kenya

To determine whether maternal placental malaria is associated with an increased risk for perinatal mother-to-child HIV transmission (MTCT), we studied HIV-positive women in western Kenya. We enrolled 512 mother-infant pairs; 128 (25.0%) women had placental malaria, and 102 (19.9%) infants acquired HIV perinatally. Log10 HIV viral load and episiotomy or perineal tear were associated with increased perinatal HIV transmission, whereas low-density placental malaria (<10,000 parasites/mL) was associated with reduced risk (adjusted relative risk [ARR] 0.4). Among women dually infected with malaria and HIV, high-density placental malaria (>10,000 parasites/mL) was associated with increased risk for perinatal MTCT (ARR 2.0), compared to low-density malaria. The interaction between placental malaria and MTCT appears to be variable and complex: placental malaria that is controlled at low density may cause an increase in broad-based immune responses that protect against MTCT; uncontrolled, high-density malaria may simultaneously disrupt placental architecture and generate substantial antigen stimulus to HIV replication and increase risk for MTCT.

Malaria parasitaemia in relation to HIV status and vitamin A supplementation among pre-school children

OBJECTIVES

To ascertain whether malaria parasitaemia in children is associated with HIV status. To examine the effect of vitamin A supplementation on malaria parasitaemia in children.

METHODS

We studied the cross-sectional associations between HIV status and malaria parasitaemia among 546 children 6-60 months of age who participated in a double-blind, randomized clinical trial of vitamin A supplementation. Prevalence ratios and 95% confidence intervals (CI) were estimated for the presence of malaria parasites at baseline by HIV status in uni- and multivariate models that adjusted for sociodemographic and environmental variables. Among children with malaria, correlates of high parasite loads were identified. Next, we examined the effect of vitamin A supplementation on the risk of malaria parasitaemia and high parasite density at 4-8 months of the first dose in a subset of children.

RESULTS

The prevalence of malaria parasitaemia was 11.4% among HIV-infected children, compared with 27.6% among uninfected. After adjusting for season, anaemia, use of bednets, maternal education and indicators of socioeconomic status, we found some evidence for lower prevalence of parasitaemia among HIV positive compared with HIV-negative children (prevalence ratio=0.56; 95% CI=0.29, 1.09; P=0.09). Other important correlates of malaria parasitaemia at baseline included low level of maternal education, poor quality of water supply, and the presence of animals at home. Vitamin A supplementation did not have a significant effect on malaria parasitaemia at 4-8 months of follow-up, overall or within levels of potential effect modifiers.

CONCLUSION

HIV infection appears to be negatively correlated with malaria parasitaemia in this group of children. Investing in women's education is likely to decrease the prevalence of malaria parasitaemia in children. Vitamin A supplementation does not seem to have an effect on malaria parasitaemia in this population; possible benefits against clinical episodes and severe malaria deserve further examination.

Effect of Maternal HIV and Malaria Infection on Pregnancy and Perinatal Outcome in Zimbabwe

OBJECTIVE

To investigate the effect of isolated or concomitant infection with malaria and HIV on pregnancy and neonatal outcome.

METHODS

Data were collected on pregnant women admitted during the rainy seasons in the obstetric division of a district referral hospital in northern Zimbabwe in 2000 and 2001. The effects of malaria and HIV infection were determined by multivariate analysis.

RESULTS

The prevalence of HIV seropositivity and symptomatic malaria in 986 pregnant women was 8.3% and 14.7%, respectively. HIV-infected women were more likely to develop malaria attacks during pregnancy than seronegative women (odds ratio [OR] = 3.96, 95% confidence interval (CI): 2.42-6.46). Malaria and HIV infections were associated with increased risk of stillbirth (OR = 4.74, 95% CI: 1.34-16.78) and preterm delivery (OR = 4.10, 95% CI: 2.17-7.75), respectively. They were independently associated with increased risk of low birth weight (malaria: OR = 10.09, 95% CI: 6.50-15.65; HIV: OR = 3.16, 95% CI: 1.80-5.54) and very low birth weight (malaria: OR = 5.04, 95% CI: 1.00-25.43; HIV: OR = 10.74, 95% CI: 2.12-54.41), low Apgar score (malaria: OR = 4.45, 95% CI: 1.42-13.94; HIV: OR = 5.94, 95% CI: 1.66-21.30), and fetal growth restriction (malaria: OR = 3.98, 95% CI: 2.51-6.30; HIV: OR = 4.07, 95% CI: 2.40-6.92). Dual infection with malaria and HIV was associated with increased risk of maternal, perinatal, and early infant death.

CONCLUSIONS

Women with single HIV or malaria infection have a significantly increased risk of adverse outcomes of pregnancy and childbirth. Dual infection has additional detrimental effects on maternal and infant survival in an area where HIV and malaria coexist.

Estimating HIV prevalence and the impact of HIV/AIDS on a Ugandan hospital by combining serosurvey data and hospital discharge records

OBJECTIVE

To estimate the disease-specific HIV prevalence in a northern Ugandan hospital and to evaluate the impact of HIV/AIDS on hospital services.

DESIGN

HIV serosurvey and analysis of routinely compiled hospital records.

METHODS

The serosurvey was conducted among all 352 patients admitted to the medical ward of the Lacor Hospital in March 1999 (this ward consists of 3 units: general medicine, tuberculosis, and cancer). The impact on hospital services was estimated using the hospital discharge records for all 3447 patients admitted in 1999, in combination with serosurvey data, and was expressed as the percentage of bed-days attributable to HIV-positive patients.

RESULTS

The overall HIV prevalence was 42.0% (52.6, 44.6, and 13.2% in the general medicine, tuberculosis, and cancer units, respectively). The disease-specific prevalence ranged from 45-65% for patients with tuberculosis, pneumonia, malaria, and enteritis. HIV-positive patients, compared with HIV-negative patients, had a higher in-hospital mortality (14.6 vs. 3.0%) and a lower average length of stay (41.4 vs. 48.9 days). AIDS cases accounted for 5.0% of hospital admissions, 4.1% of bed-days, and 11.5% of deaths. When considering all HIV-positive patients, these accounted for 37.2% of the bed-days.

CONCLUSIONS

Knowledge of disease-specific HIV prevalence and of the patterns of HIV-related diseases is crucial for early case management. The impact of HIV-positive patients on hospital services is quite high, accounting for >1/3 of the bed-days in 1999. Providing a continuum of care through inpatient, outpatient, and outreach home care services probably represents the only means of relieving the pressure on overloaded hospitals.

Total lymphocyte count and hemoglobin combined in an algorithm to initiate the use of highly active antiretroviral therapy in resource-limited settings

OBJECTIVE

To develop clinical algorithms that improve the sensitivity of surrogate markers to initiate the use of highly active antiretroviral therapy (HAART) in resource-limited settings.

DESIGN

A retrospective evaluation of total lymphocyte counts (TLC) and hemoglobin to predict the CD4 lymphocyte count.

METHODS

A total of 3269 members of the Johns Hopkins HIV observational cohort contributed 22 690 paired observations of CD4 lymphocyte counts and TLC. Two methods were used to evaluate the effect of combining TLC and hemoglobin to predict CD4 cell counts below 200 cells/mm3 before the initiation of HAART in 1451 participants; 55.3% of participants had CD4 cell counts below 200 cells/mm3.

RESULTS

TLC below 1200 cells/mm3 and hemoglobin below 12 g/dl significantly predicted CD4 cell counts below 200 cells/mm3. For TLC alone sensitivity was 70.7% and specificity was 81.7%. For both men and women, we chose a TLC lower cutoff point of 1200 cells/mm3, an upper cutoff point of 2000 cells/mm3, and hemoglobin of 12 g/dl. For men, method I generated sensitivity of 78.0% and specificity of 77.5%. Method II improved specificity to 81.8%. For women, method I increased sensitivity to 85.6% and decreased specificity to 64.1%. Method II improved specificity to 81.4%.

CONCLUSION

TLC below 1200 cells/mm3 were associated with CD4 cell counts below 200 cells/mm3 as in the WHO guidelines, but sensitivity was low. Adding hemoglobin to TLC increased sensitivity, thereby reducing the risk of false-negative results. Our model may serve as a template for the development of algorithms to initiate the use of HAART in resource-limited settings.

Does infection with Human Immunodeficiency Virus affect the antibody responses to Plasmodium falciparum antigenic determinants in asymptomatic pregnant women?

OBJECTIVES

HIV-seropositive pregnant women are more susceptible to malaria than HIV-seronegative women. We assessed whether HIV infection alters maternal and cord plasma malarial antibody responses and the mother-to-infant transfer of malaria antibodies.

METHODS

We determined plasma levels of maternal and cord antibodies [Immunoglobulin (IgG)] to recombinant malarial proteins [merozoite surface protein 1 (MSP-1(19kD)), the erythrocyte binding antigen (EBA-175)], the synthetic peptides [MSP-2, MSP-3, rhoptry associated protein 1 (RAP-1), and the pre-erythrocytic stage, circumsporozoite protein (NANP)(5)] antigenic determinants of Plasmodium falciparum; and tetanus toxoid (TT) by ELISA among samples of 99 HIV-seropositive mothers, 69 of their infants, 102 HIV-seronegative mothers and 62 of their infants.

RESULTS

The prevalence of maternal antibodies to the malarial antigenic determinants ranged from 18% on MSP3 to 91% on EBA-175; in cord plasma it ranged from 13% to 91%, respectively. More than 97% of maternal and cord samples had antibodies to TT. In multivariate analysis, HIV infection was only associated with reduced antibodies to (NANP)(5) in maternal (P=0.001) and cord plasma (P=0.001); and reduced mother-to-infant antibody transfer to (NANP)(5) (P=0.012). This effect of HIV was independent of maternal age, gravidity and placental malaria. No consistent HIV-associated differences were observed for other antigenic determinants.

CONCLUSION

An effect of HIV infection was only observed on one malarial antigenic determinant, suggesting that the increased susceptibility to malaria among HIV-infected pregnant women may not be explained on the basis of their reduced antibody response to malaria antigens.

HIV-1/AIDS and the control of other infectious diseases in Africa

The effect of HIV-1 on other infectious diseases in Africa is an increasing public health concern. In this review, we describe the role that three major infectious diseases--malaria, sexually transmitted diseases (STDs), and tuberculosis--have had in the HIV-1 epidemic. The high prevalence of untreated STD infections has been a major factor facilitating the spread of HIV-1 in Africa; with the synergistic interaction between HIV-1 transmission and genital herpes being of special concern for control of both diseases. Increased susceptibility to tuberculosis after infection with HIV-1 has led to a rising incidence and threat of increased transmission of tuberculosis. Clinical malaria occurs with an increased frequency and severity in HIV-1-infected individuals, especially during pregnancy. As with tuberculosis, STDs, and other communicable HIV-1-associated diseases, the net effect of HIV-1 might include increased rates of malaria transmission across communities. In addition to enhancing access to HIV-1 prevention and care, public health surveillance and control programmes should be greatly intensified to cope with the new realities of infectious disease control in Africa.