Epidemiology of HIV andSchistosoma mansoniinfections among sugar-estate residents in Ethiopia

Prevalence and Intensity of Schistosoma mansoni Infection and Its Associated Risk Factors Among Patients with and without HIV at Chuahit Health Center, Dembia District, Northwest Ethiopia

BACKGROUND

Human Immunodeficiency Virus-1/AIDS and Schistosoma mansoni are widely spread in sub-Saharan Africa including Ethiopia and the co-infection is also prevalent, occurs commonly. Schistosoma mansoni infection has been suggested to be a risk factor for HIV transmission and progression. This study aims to assess the prevalence and intensity of Schistosoma mansoni infection and associated risk factors among individuals with and without human immunodeficiency virus (HIV) at Chuahit Health Center, West Dembia, Northwest Ethiopia.

METHODS

Institutional based cross-sectional study was conducted from March to April 2019. Two hundred sixty-six study subjects were included in the study by using a systemic and convenient sampling technique. Pretested structured questionnaire was employed to collect data. Single stool samples were collected and examined for S. mansoni eggs. Finger prick and venous blood samples were collected for HIV-1 screening and viral load count. Data were analyzed using SPSS version 20. Independent t-test and one-way ANOVA were used to compare the mean of egg counts with HIV status and viral load counts, respectively. A P-value of less than 0.05 was taken as statistically significant.

RESULTS

The overall prevalence and intensity of S. mansoni infection was 41 (15.4%) and 162.24 egg per gram of faeces (EPG), respectively. Prevalence of S. mansoni was higher in seronegative study participants though the difference is statistically insignificant. Higher intensity of infection was observed among seropositive study participants with high viral load counts (>1000 copies/mL).

CONCLUSION

Relatively higher prevalence and intensity of S. mansoni infection were found. Study participants' occupation was identified as potential risk factor to S. mansoni infection. Further studies are needed to know the impact of HIV on the prevalence and intensity of S. mansoni infection in the study area.

Beyond the barrier: Female Genital Schistosomiasis as a potential risk factor for HIV-1 acquisition

Female genital schistosomiasis (FGS) results from egg-deposition in the female reproductive tract primarily by the waterborne parasite Schistosoma (S.) haematobium, and less commonly by Schistosoma (S.) mansoni. FGS affects an estimated 20-56 million women worldwide, mostly in sub-Saharan Africa. There is cross-sectional evidence of increased HIV-1 prevalence in schistosomiasis-infected women, but a causal relationship between FGS and either HIV-1 acquisition or transmission has not been fully established. Beyond the pathognomonic breach in the cervicovaginal barrier caused by FGS, this narrative review explores potential mechanisms for a synergistic relationship between S. haematobium infection, FGS, and HIV-1 acquisition through vaginal inflammation and target cell recruitment.

Schistosoma haematobium infection and environmental factors in Southwestern Tanzania: A cross-sectional, population-based study

Schistosomiasis is a leading cause of morbidity in Africa. Understanding the disease ecology and environmental factors that influence its distribution is important to guide control efforts. Geographic information systems have increasingly been used in the field of schistosomiasis environmental epidemiology. This study reports prevalences of Schistosoma haematobium infection and uses remotely sensed and questionnaire data from over 17000 participants to identify environmental and socio-demographic factors that are associated with this parasitic infection. Data regarding socio-demographic status and S. haematobium infection were obtained between May 2006 and May 2007 from 17280 participants (53% females, median age = 17 years) in the Mbeya Region, Tanzania. Combined with remotely sensed environmental data (vegetation cover, altitude, rainfall etc.) this data was analyzed to identify environmental and socio-demographic factors associated with S. haematobium infection, using mixed effects logistic regression and geostatistical modelling. The overall prevalence of S. haematobium infection was 5.3% (95% confidence interval (CI): 5.0-5.6%). Multivariable analysis revealed increased odds of infection for school-aged children (5-15 years, odds ratio (OR) = 7.8, CI: 5.9-10.4) and the age groups 15-25 and 25-35 years (15-25 years: OR = 5.8, CI: 4.3-8.0, 25-35 years: OR = 1.6, CI: 1.1-2.4) compared to persons above 35 years of age, for increasing distance to water courses (OR = 1.4, CI: 1.2-1.6 per km) and for proximity to Lake Nyasa (<1 km, OR = 4.5, CI: 1.8-11.4; 1-2 km, OR = 3.5, CI: 1.7-7.5; 2-4 km; OR = 3.3, CI: 1.7-6.6), when compared to distances >4 km. Odds of infection decreased with higher altitude (OR = 0.7, CI: 0.6-0.8 per 100 m increase) and with increasing enhanced vegetation index EVI (OR = 0.2, CI: 0.1-0.4 per 0.1 units). When additionally adjusting for spatial correlation population density became a significant predictor of schistosomiasis infection (OR = 1.3, CI: 1.1-1.5 per 1000 persons/km2) and altitude turned non-significant. We found highly focal geographical patterns of S. haematobium infection in Mbeya Region in Southwestern Tanzania. Despite low overall prevalence our spatially heterogeneous results show that some of the study sites suffer from a considerable burden of S. haematobium infection, which is related to various socio-demographic and environmental factors. Our results could help to design more effective control strategies in the future, especially targeting school-aged children living in low altitude sites and/or crowded areas as the persons at highest need for preventive chemotherapy.

Interactions of Schistosoma and HIV in Sub-Saharan Africa: A Systematic Review

Schistosomiasis is an acute and chronic parasitic disease caused by blood flukes of the genus Schistosoma. More than 220 million people worldwide were estimated to have active schistosomiasis in 2017, 90% of whom live on the African continent, but only 102 million were reported to have received treatment. Africa is also disproportionately burdened by HIV, with an estimated 26 million people living with HIV in 2017. Given these overlapping epidemics, we conducted a systematic review to ascertain the contribution of schistosomes to HIV acquisition risk, the contribution of HIV to schistosome acquisition, the impact of HIV on schistosomiasis-related morbidity, the impact of schistosomes on HIV disease progression and immune response, the impact of HIV on the efficacy of praziquantel treatment, and the impact of HIV on egg shedding. We reviewed studies of people living in sub-Saharan Africa coinfected with HIV and Schistosoma spp. between January 1996 and July 2018. We found that 1) infection with Schistosoma haematobium increases the risk of HIV acquisition, 2) there is currently a lack of data on whether HIV infection increases the risk of Schistosoma acquisition, 3a) HIV coinfection was not an accelerating factor for adverse Schistosoma outcomes, 3b) schistosomiasis may be an important contributor to immune activation in HIV coinfected people, 4) praziquantel use in coinfected people may improve immune reconstitution on antiretroviral therapy for HIV, and 5) there is evidence that HIV infection reduces egg excretion in individuals infected with Schistosoma mansoni.

Associations between schistosomiasis and HIV-1 acquisition risk in four prospective cohorts: a nested case-control analysis

INTRODUCTION

Globally, schistosomes infect approximately 200 million people, with 90% of infections in sub-Saharan Africa. Schistosomiasis is hypothesized to increase HIV-1 acquisition risk, and multiple cross-sectional studies reported strong associations. We evaluated this hypothesis within four large prospective cohorts.

METHODS

We conducted nested case-control analyses within three longitudinal cohorts of heterosexual HIV-1 serodiscordant couples and one female sex worker (FSW) cohort from Kenya and Uganda. The serodiscordant couples studies were conducted between 2004 and 2012 while the FSW cohort analysis included participant follow-up from 1993 to 2014. Cases HIV-1 seroconverted during prospective follow-up; three controls were selected per case. The presence of circulating anodic antigen in archived serum, collected prior to HIV-1 seroconversion, identified participants with active schistosomiasis; immunoblots determined the schistosome species. Data from serodiscordant couples cohorts were pooled, while the FSW cohort was analysed separately to permit appropriate confounder adjustment.

RESULTS

We included 245 HIV-1 seroconverters and 713 controls from the serodiscordant couples cohorts and 330 HIV-1 seroconverters and 962 controls from the FSW cohort. The prevalence of active schistosomiasis was 20% among serodiscordant couples and 22% among FSWs. We found no association between schistosomiasis and HIV-1 acquisition risk among males (adjusted odds ratio (aOR) = 0.99, 95% CI 0.59 to 1.67) or females (aOR = 1.21, 95% CI 0.64 to 2.30) in serodiscordant couples. Similarly, in the FSW cohort we detected no association (adjusted incidence rate ratio (aIRR) = 1.11, 95% CI 0.83 to 1.50). Exploring schistosome species-specific effects, there was no statistically significant association between HIV-1 acquisition risk and Schistosoma mansoni (serodiscordant couples: aOR = 0.90, 95% CI 0.56 to 1.44; FSW: aIRR = 0.83, 95% CI 0.53 to 1.20) or Schistosoma haematobium (serodiscordant couples: aOR = 1.06, 95% CI 0.46 to 2.40; FSW: aIRR = 1.64, 95% CI 0.93 to 2.87) infection.

CONCLUSIONS

Schistosomiasis was not a strong risk factor for HIV-1 acquisition in these four prospective studies. S. mansoni was responsible for the majority of schistosomiasis in these cohorts, and our results do not support the hypothesis that S. mansoni infection is associated with increased HIV-1 acquisition risk. S. haematobium infection was associated with a point estimate of elevated HIV-1 risk in the FSW cohort that was not statistically significant, and there was no trend towards a positive association in the serodiscordant couples cohorts.

The extent, nature, and pathogenic consequences of helminth polyparasitism in humans: A meta-analysis

Background

Individual helminth infections are ubiquitous in the tropics; geographical overlaps in endemicity and epidemiological reports suggest areas endemic for multiple helminthiases are also burdened with high prevalences of intestinal protozoan infections, malaria, tuberculosis (TB), and human immunodeficiency virus (HIV). Despite this, pathogens tend to be studied in isolation, and there remains a need for a better understanding of the community ecology and health consequences of helminth polyparasitism to inform the design of effective parasite control programs.

Methodology

We performed meta-analyses to (i) evaluate the commonality of polyparasitism for helminth-helminth, helminth-intestinal protozoa, helminth-malaria, helminth-TB, and helminth-HIV co-infections, (ii) assess the potential for interspecies interactions among helminth-helminth and helminth-intestinal protozoan infections, and (iii) determine the presence and magnitude of association between specific parasite pairs. Additionally, we conducted a review of reported health consequences of multiply-infected individuals compared to singly- or not multiply-infected individuals.

Principal findings

We found that helminth-helminth and helminth-intestinal protozoan multiple infections were significantly more common than single infections, while individuals with malaria, TB, and HIV were more likely to be singly-infected with these infections than co-infected with at least one helminth. Most observed species density distributions significantly differed from the expected distributions, suggesting the potential presence of interspecies interactions. All significant associations between parasite pairs were positive in direction, irrespective of the combination of pathogens. Polyparasitized individuals largely exhibited lower hemoglobin levels and higher anemia prevalence, while the differences in growth-related variables were mostly statistically insignificant.

Conclusions

Our findings confirm that helminth polyparasitism and co-infection with major diseases is common in the tropics. A multitude of factors acting at various hierarchical levels, such as interspecies interactions at the within-host infra-parasite community level and environmental variables at the higher host community level, could explain the observed positive associations between pathogens; there remains a need to develop new frameworks which can consider these multilevel factors to better understand the processes structuring parasite communities to accomplish their control.

Helminth infections are a highly prevalent global health problem. These parasitic worm infections occur in areas also burdened with intestinal protozoan infections, malaria, tuberculosis, and human immunodeficiency virus. While these pathogens tend to be studied in isolation, there remains a need to better understand the nature, extent, and health consequences of helminth polyparasitism and co-infection with major diseases. Here, we reviewed the literature and performed meta-analyses to evaluate the commonality of helminth polyparasitism and co-infection, the potential for interspecies interactions between parasites, the association between parasite pairs, and the health consequences among multiply-infected individuals. We confirmed that polyparasitism and co-infection with major diseases are common in the global South and found that multiply-infected individuals experienced worse health consequences when compared to singly or not-multiply infected individuals. Our analysis suggested the potential presence of interspecies interactions and we identified the existence of positive associations between parasite pairs. These findings support the call for integrating deworming into malaria, TB, and HIV treatment protocols and suggest there remains a need to improve our understanding of the factors influencing co-transmission to achieve sustainable parasite control.

Spatial clustering and socio-demographic determinants of HIV infection in Ethiopia, 2015-2017

BACKGROUND

Amhara Region has the largest at-risk population in Ethiopia, with widespread traditional practices that are likely to increase transmission of HIV. However, the identification and characterization of HIV hotspots within this region have not been undertaken. This study aimed to explore and describe the geographical pattern of HIV infection using notification data in Amhara Region, Ethiopia.

METHODS

Data on HIV infection at the district level were obtained from the Amhara Regional Health Bureau. A Bayesian conditional autoregressive (CAR) model was used to explore the association between HIV infection and socio-demographic variables in OpenBUGS.

RESULTS

A total of 35 210 new HIV cases were reported during 2015-2017 in Amhara Region, Ethiopia. Metema and Mirab Armacho districts were found to be hotspots throughout the study period. There was a decrease in HIV infection in 2016 (odds ratio 0.77, 95% credible interval (CrI) 0.72-0.82) and 2017 (odds ratio 0.71, 95% CrI 0.60-0.76) as compared with HIV infection in 2015. HIV infection increased by 1.004 (95% CrI 1.001-1.008) and 1.47 (95% CrI 1.11-3.59) for a one-unit increase in the proportion of the population who had never attended school and migrants, respectively.

CONCLUSIONS

This study identified spatial clustering of HIV infection in Amhara Region, with a slight reduction in the annual infection rates from 2015 to 2017. The proportion of the population who were migrants or who had a low educational status was associated with a high risk of infection. Access to HIV counselling and the promotion of condom utilization, integrated with other health care services, targeting those with a lower level of education and seasonal migrants, are important strategies for the prevention of new HIV infections.

Immune Dysfunction and Coinfection with Human Immunodeficiency Virus and Schistosoma japonicum in Yi People

Objective

To explore the association between infections with HIV and Schistosoma japonicum, and to determine the influences of the HIV-S. japonicum coinfections on the immune system of Yi people.

Methods

A block design study was conducted in a Yi county in southwestern China, one of the endemic areas of both HIV/AIDS and S. japonicum in China. All participants were screened for HIV antibodies and S. japonicum antibodies (SjAb) and were classified into four groups: HIV(+)/S. japonicum(−), HIV(−)/S. japonicum (+), HIV(+)/S. japonicum(+), and HIV(−)/S. japonicum(−).

Results

There were significant differences among the four groups in both CD4⁺ T lymphocytes and CD8⁺ T lymphocytes, but no significant difference in CD3⁺ T lymphocytes. Both the CD4⁺ T lymphocyte counts and the ratio of CD4⁺/CD8⁺ were lower in HIV-infected people compared with those uninfected. People infected with S. japonicum had increased CD4⁺ T lymphocyte counts but reduced CD8⁺ T lymphocyte counts. Similarly, the ratio of CD4⁺/CD8⁺ was higher in S. japonicum-infected people compared with those uninfected. People coinfected with HIV and S. japonicum had lower CD4⁺ T lymphocyte counts, lower ratio of CD4⁺/CD8⁺, and higher CD8⁺ T lymphocyte counts compared with those infected with HIV only or S. japonicum only. People infected with HIV only and those coinfected with HIV and S. japonicum had a higher level of IFN-γ compared with people with no infection. There were no significant differences between people infected with HIV only and with S. japonicum only in the levels of IFN-γ and IL-10.

Conclusions

People coinfected with HIV and S. japonicum might have a suppressed immune function because of a decrease in CD4⁺ T lymphocyte counts, a lowered ratio of CD4⁺/CD8⁺, and an increase in CD8⁺ T lymphocyte counts. Coinfection with HIV and S. japonicum would alter the level of IFN-γ in plasma.

Sensitivity and specificity of point-of-care circulating Cathodic antigen test before and after praziquantel treatment in diagnosing Schistosoma mansoni infection in adult population co-infected with human immunodeficiency virus-1, North-Western Tanzania

Background

The effect of Human Immunodeficiency Virus-1 (HIV-1) on CD4⁺ Th₂ cells is hypothesized to affect parasitological diagnosis of Schistosoma mansoni using Kato Katz technique. Thus, the use of more sensitive technique such as Point-of-Care Circulating Cathodic Antigen (POC-CCA) test is recommended. However, the sensitivity of this diagnostic test in diagnosing S.mansoni infection and the usefulness of it in monitoring efficacy of praziquantel drug in presence of HIV-1 co-infection remains inconclusive. The Primary objective of the present study was to assess accuracy of the POC-CCA test in diagnosing S.mansoni infection before and after praziquantel treatment in adult population co-infected with HIV -1.

Methods

A prospective longitudinal study was conducted among individuals aged 15–55 years at Igalagala village, north-western Tanzania. At baseline and 4 weeks after treatment, a single stool and urine samples were collected from each participants. Kato Katz (KK) technique and Point-of-Care Circulating Cathodic Antigen tests were used for diagnosis of Schistosoma mansoni.

Results

At baseline, based on KK and POC-CCA, the prevalence of S.mansoni was 57.8% (95%CI: 52.9–62.4) and 87.5% (95%CI: 83.9–90.4). Based on KK technique and POC-CCA test, 3.6% and 5.7% of the study participants were co-infected with S.mansoni and HIV-1. At baseline, in the general population, the sensitivities of POC-CCA test using KK technique and combine gold standard were 96.3%(95%CI: 93.1–98.3) and 97.6%(95%CI:95.5–98.9) respectively. In the HIV-1 seropositive group, at baseline, the sensitivities of POC-CCA test using KK technique and combined gold standards, were 93.3%(95%CI:68.1–99.8) and 96%(95CI%:79.6–99.9). Four weeks after treatment, in general population, the sensitivities of POC-CCA test using KK technique and combined gold standards were 47.8%(95%CI:26.8–69.4) and 84.4%(95%CI:74.4–91.7). In the HIV-1 seropositive group, using KK technique, the sensitivity was 100% (95%CI:2.5–100).

Conclusion

The sensitivity of POC-CCA in diagnosing S.mansoni infection was higher than KK technique in adult individuals likely to have low infection intensity and co-infected with HIV-1. However, its sensitivity decreases following praziquantel treatment but remained higher than Kato Katz technique. If the goal of the post-treatment is to identify uncured individuals, then POC-CCA test offers the best choice.

Diagnostic Performance of Kato Katz Technique and Point-of-Care Circulating Cathodic Antigen Rapid Test in Diagnosing Schistosoma mansoni Infection in HIV-1 Co-Infected Adults on the Shoreline of Lake Victoria, Tanzania

Background: The diagnostic performance of the Kato Katz (KK) technique and the point-of-care circulating cathodic antigen (POC-CCA) test in detecting S. mansoni infection in the presence of the human immunodeficiency virus-1 (HIV-1) infection has remained inconclusive. The present cross-sectional survey compared the diagnostic performance of the KK technique and the POC-CCA test in diagnosing S. mansoni infection in an adult population co-infected with HIV-1 in northwestern Tanzania. Methods: Single urine and stool samples from 979 adults were screened for S. mansoni infection using both the KK technique and POC-CCA tests. To compare the performance of the two diagnostic tests a combined artificial gold standard was created, based on either an egg-positive KK technique or a POC-CCA-positive test. Results: Based on the KK technique, the prevalence of S. mansoni was 47.3% (463/979, 95% CI: 44.2–50.4), as compared to 60.5% by the POC-CCA test (592/979; 95% CI: 57.4–63.5). The overall sensitivity and specificity of the POC-CCA test were 92.5% (95% CI: 89.4–94.9) and 73.3% (95% CI: 69.6–76.8), respectively. In the HIV-1 seropositive group, the sensitivity and specificity of the POC-CCA test were 78.1% (95% CI: 60.0–90.7) and 45.9% (95% CI: 35.8–56.3). Using a combined gold standard, the sensitivity of the POC-CCA test increased to >90% in both subgroups whereas that of the KK technique in the HIV-1 seropositive group was low (49.5%; 95% CI: 39.6–59.5). Conclusion: In the presence of HIV-1 co-infection, the KK technique attained a very low sensitivity. The POC-CCA test offers the best option for the rapid screening of S. mansoni infection in communities with a high prevalence of HIV-1 infection.

Decreased Sensitivity of Schistosoma sp. Egg Microscopy in Women and HIV-Infected Individuals

It has been postulated that impaired host immunity due to HIV infection reduces parasite egg excretion. Schistosoma/HIV interactions have also been shown to differ by sex. We hypothesized that egg excretion would vary based on both HIV status and sex. We examined data from more than 1,700 participants in eight studies conducted in northwest Tanzania between 2010 and 2016. Schistosoma infection was defined by circulating anodic antigen (CAA) serum levels ≥ 30 pg/mL and/or egg positivity in either stool by Kato Katz method or urine by filtration. We used multivariable analyses to determine the impact of confounding factors such as sex, age, previous praziquantel treatment, and worm burden as measured by serum CAA level, on the relationship between egg excretion and HIV status. HIV-infected individuals were significantly less likely to excrete schistosome eggs than HIV-uninfected individuals, even after controlling for worm burden and sex (OR = 0.6 [0.4, 0.9], P = 0.005). Furthermore, after controlling for worm burden and HIV status, women had lower odds of egg excretion than men (OR = 0.4 [0.3, 0.5], P < 0.001). Sensitivity of egg microscopy was lower in HIV-infected women than HIV-uninfected men (41% versus 61%, P < 0.001), whereas sensitivity in women remained low in both groups (33% versus 37%, P = 0.664). Our study is the first to report that women with Schistosoma infection excrete fewer eggs than men for a given worm burden, regardless of HIV the status. These findings suggest that guidelines for use of microscopy to diagnose Schistosoma infections in HIV-infected individuals and in women merit reconsideration.

Association between CD4+ T-lymphocyte counts and fecal excretion of Schistosoma mansoni eggs in patients coinfected with S. mansoni and human immunodeficiency virus before and after initiation of antiretroviral therapy

Previously, we have shown that persons with human immunodeficiency virus 1 (HIV-1) infection and reduced CD4(+) T-lymphocyte counts excrete significantly fewer Schistosoma mansoni eggs than HIV-1-negative persons with similar intensities of schistosome infections. To determine how antiretroviral therapy (ART) might affect egg excretion, we conducted a study of HIV+ adults living in an area highly endemic for S. mansoni as they began an ART program. Fecal egg excretion and CD4(+) T-lymphocyte counts were evaluated at enrollment as well as 2 and 4 weeks after initiation of ART. Fourteen individuals who were Kato-Katz-negative at enrollment subsequently started excreting S. mansoni eggs accompanied by a significant increase in CD4(+) T lymphocytes (P = 0.004). Study participants who were S. mansoni egg-positive at enrollment and received both praziquantel and ART also showed significantly increased CD4(+) T-lymphocyte counts compared with baseline (P < 0.0001). Our data support a role for CD4(+) T lymphocytes in S. mansoni egg excretion.

Association of Schistosomiasis and HIV infection in Tanzania

Animal and human studies suggest that Schistosoma mansoni infection may increase risk of human immunodeficiency virus (HIV) acquisition. Therefore, we tested 345 reproductive age women in rural Tanzanian villages near Lake Victoria, where S. mansoni is hyperendemic, for sexually transmitted infections (STIs) and schistosomiasis by circulating anodic antigen (CAA) serum assay. Over one-half (54%) had an active schistosome infection; 6% were HIV-seropositive. By univariate analysis, only schistosome infection predicted HIV infection (odds ratio [OR] = 3.9, 95% confidence interval = [1.3-12.0], P = 0.015) and remained significant using multivariate analysis to control for age, STIs, and distance from the lake (OR = 6.2 [1.7-22.9], P = 0.006). HIV prevalence was higher among women with more intense schistosome infections (P = 0.005), and the median schistosome intensity was higher in HIV-infected than -uninfected women (400 versus 15 pg CAA/mL, P = 0.01). This finding suggests that S. mansoni infection may be a modifiable HIV risk factor that places millions of people worldwide at increased risk of HIV acquisition.

A wake up call for urinary schistosomiasis: reconciling research effort with public health importance

This review considers the current status of urinary schistosomiasis, caused by infection with Schistosoma haematobium, and argues that greater research effort and focus are needed to improve understanding of this neglected tropical disease (NTD). The inappropriateness of relying solely on data concerning the much more extensively studied intestinal form of schistosomiasis caused by S. mansoni is highlighted. The current lack of genome and transcriptome information for S. haematobium is directly hindering further targeted research and must be quickly rectified. Recent molecular phylogenies caution the expectation of similarities between schistosome species and highlight the close relationships of species within the S. haematobium group. Treatment, current and prospective drugs and vaccines, together with diagnosis are considered, highlighting the differences associated with urinary schistosomiasis. This infection has a significant and specific impact on the urino-genital system and has a strong association with bladder cancer, leading to severe and chronic morbidity. There is a clear need for new clinical initiatives in this area to better quantify the disease burden. Furthermore, emerging associations with HIV and other pathogens need to be closely monitored. Research is urgently needed to improve current knowledge in order to develop the next generation of control tools.

Education and vulnerability: the role of schools in protecting young women and girls from HIV in southern Africa

Education has a potentially important role to play in tackling the spread of HIV, but is there evidence that this potential is realized? This analysis combines the results of previous literature reviews and updates them with the findings of recent randomized controlled trials and a discussion of possible mechanisms for the effect of schooling on vulnerability to HIV infection. There is a growing body of evidence that keeping girls in school reduces their risk of contracting HIV. The relationship between educational attainment and HIV has changed over time, with educational attainment now more likely to be associated with a lower risk of HIV infection than earlier in the epidemic. Educational attainment cannot, however, be isolated from other socioeconomic factors as the cause of HIV risk reduction. The findings of this analysis suggest that the equitable expansion of primary and secondary schooling for girls in southern Africa will help reduce their vulnerability to HIV. Evidence of ineffective HIV prevention education in schools underlines the need for careful evidence-based programme design. Despite the challenges, recent provisional evidence suggests that highly targeted programmes promoting realistic options for young adults may lead to safer sexual behaviour. Targeted education programmes have also been successful in changing students' attitudes to people living with HIV and AIDS, which is associated with testing and treatment decisions. This reduction in stigma may be crucial in encouraging the uptake of voluntary counselling and testing, a central strategy in the control of the epidemic. Expansions of carefully designed and evaluated school-based HIV prevention programmes can help to reduce stigma and have the potential to promote safe sexual behaviour.

Systematic review exploring time trends in the association between educational attainment and risk of HIV infection in sub-Saharan Africa

OBJECTIVE

To assess the evidence that the association between educational attainment and risk of HIV infection is changing over time in sub-Saharan Africa.

DESIGN AND METHODS

Systematic review of published peer-reviewed articles. Articles were identified that reported original data comparing individually measured educational attainment and HIV status among at least 300 individuals representative of the general population of countries or regions of sub-Saharan Africa. Statistical analyses were required to adjust for potential confounders but not over-adjust for variables on the causal pathway.

RESULTS

Approximately 4000 abstracts and 1200 full papers were reviewed. Thirty-six articles were included in the study, containing data on 72 discrete populations from 11 countries between 1987 and 2003, representing over 200,000 individuals. Studies on data collected prior to 1996 generally found either no association or the highest risk of HIV infection among the most educated. Studies conducted from 1996 onwards were more likely to find a lower risk of HIV infection among the most educated. Where data over time were available, HIV prevalence fell more consistently among highly educated groups than among less educated groups, in whom HIV prevalence sometimes rose while overall population prevalence was falling. In several populations, associations suggesting greater HIV risk in the more educated at earlier time points were replaced by weaker associations later.

DISCUSSION

HIV infections appear to be shifting towards higher prevalence among the least educated in sub-Saharan Africa, reversing previous patterns. Policy responses that ensure HIV-prevention measures reach all strata of society and increase education levels are urgently needed.

Education attainment and the risk of HIV-1 infections in rural Kilimanjaro Region of Tanzania, 1991-2005: a reversed association

OBJECTIVE

Previous studies found educated individuals to have higher risk of human immunodeficiency virus (HIV)-1 infection in Africa. A reverse in this association was predicted. We investigated the change in this association from 1991 to 2005 in a rural population in Tanzania.

STUDY DESIGN

Two cross-sectional surveys were conducted in 1991(N = 1,152, response rate 76.4%) and 2005 (N = 1,528, 73.0%). Consenting individuals aged 15 to 44 years living in Oria village were interviewed and gave blood for HIV-1 testing.

RESULTS

Primary [adjusted odds ratio (AOR), 2.7; 95% confidence interval (CI): 1.3-20.0] and secondary/higher education (AOR, 4.5; 95% CI: 1.4-24.9) were associated with increased risk of HIV-1 infection in 1991. A reversed association was observed in 2005 where reduced odds of infection were associated with primary (AOR, 0.5; 95% CI: 0.2-0.8) and secondary/higher education (AOR, 0.4; 95% CI: 0.3-0.9). This was most pronounced among educated men. Corresponding reduction in risk behaviors were observed. Increased odds of reporting ever use of condom (AOR, 2.8; 95% CI: 1.1-7.3) and 70% reduction in reporting >or=2 sexual partners in the past year was observed among educated women. Educated men reported 60% reduction in the odds of reporting >or=2 sexual partners in the past month preceding the last survey.

CONCLUSIONS

A reversed association between education attainment and HIV-1 infection was observed in this population between 1991 and 2005. Education seems to have an empowering role in women. Decreased risk among educated men may have an impact on HIV-1 transmission. Improving education sector in rural areas might be instrumental in the fight against the HIV epidemic.

Educational attainment and HIV status among Ethiopian voluntary counseling and testing clients

We examined the association between HIV infection and educational attainment level among a population of 34,512 voluntary counseling and testing (VCT) clients in Ethiopia, using client data from the Family Guidance Association of Ethiopia (FGAE). Overall, more than 50 percent of the VCT clients report at least secondary level educational attainment, and HIV prevalence is 8.5 percent for men and 14.3 percent for women. HIV prevalence decreases significantly with each increase in education level for both men and women, and this association persists at secondary and higher education levels in the multivariate model. Male and female VCT clients with more than secondary level education are 58 percent and 66 percent (respectively) less likely to be HIV-positive than those with no education. HIV prevention and treatment interventions in Ethiopia should target less educated segments of the population including women, who have higher HIV prevalence and lower educational attainment than men.

The Liver in HIV in Africa

As access to antiretroviral therapy improves across the African continent, liver disease is emerging as an important cause of morbidity and mortality among HIV-infected individuals. Although coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV), along with highly active antiretroviral therapy (HAART)-induced hepatotoxicity appear to be the major causes of liver disease in this population, other diseases endemic to Africa with hepatic manifestations are influenced by HIV infection as well. In this review we present the available data on liver disease in HIV-infected populations in Africa and discuss relevant data from the rest of the world. In addition, we highlight important areas for further study.

Role of incidental and/or cured intestinal parasitic infections on profile of CD4+ and CD8+ T cell subsets and activation status in HIV-1 infected and uninfected adult Ethiopians

Intestinal parasitic infections have been suggested to cause persistent immune activation leading to an unbalanced immune state. Such a state has been proposed to be a major factor in the pathogenesis of AIDS in an African context. The present study investigated the effect of incidental parasitic infection and treatment on the profile of T cell differentiation and activation markers on CD4+ and CD8+ T cells from HIV-1 infected and uninfected adult Ethiopians. Cryopreserved PBMCs from 64 subjects (41 HIV-negative and 23 HIV-positive) with follow-up visits at 6-monthly intervals were used to compare the effect of incidental intestinal parasites and their treatment upon T cell subset profiles and activation status. The samples were stained with antibodies to various T cell differentiation and activation markers allowing naive, memory, effector, memory/effector, activated and resting CD4+ and CD8+ T cell subsets to be quantified by triple-colour FACScan. Incidental intestinal parasitic infections resulted in a significant increase in memory CD4+ T cell numbers both in HIV-negative and HIV-positive subjects (P < 0.05). There was also a significant increase in the percentage of CD8+ HLA-DR+ T cells (P < 0.05) in HIV-positive subjects co-infected with parasites. In HIV-negative subjects, a significant decline in activated cells and a significant increase in resting CD8+ T cells (P < 0.05) was observed after treatment for parasites. These data suggest that intestinal parasitic infections could result in the alteration of T cell subset counts and also in the up-regulation of T cell activation markers in peripheral blood. Treatment of parasitic infections showed a tendency to reduce the activation suggesting that, together with other community based intervention strategies, such treatment could be used to down-regulate immune activation and hence protect the host from being easily attacked by HIV.