No abstract

Human co-infection with Plasmodium falciparum and helminths is ubiquitous throughout Africa, although its public health significance remains a topic for which there are many unknowns. In this review, we adopted an empirical approach to studying the geography and epidemiology of co-infection and associations between patterns of co-infection and hemoglobin in different age groups. Analysis highlights the extensive geographic overlap between P. falciparum and the major human helminth infections in Africa, with the population at coincident risk of infection greatest for hookworm. Age infection profiles indicate that school-age children are at the highest risk of co-infection, and re-analysis of existing data suggests that co-infection with P. falciparum and hookworm has an additive impact on hemoglobin, exacerbating anemia-related malarial disease burden. We suggest that both school-age children and pregnant women--groups which have the highest risk of anemia--would benefit from an integrated approach to malaria and helminth control.

SummaryBackgroundMalaria is a major cause of morbidity and mortality in early childhood, yet its consequences for health and education during the school-age years remain poorly understood. We examined the effect of intermittent preventive treatment (IPT) in reducing anaemia and improving classroom attention and educational achievement in semi-immune schoolchildren in an area of high perennial transmission.MethodsA stratified, cluster-randomised, double-blind, placebo-controlled trial of IPT was done in 30 primary schools in western Kenya. Schools were randomly assigned to treatment (sulfadoxine-pyrimethamine in combination with amodiaquine or dual placebo) by use of a computer-generated list. Children aged 5–18 years received three treatments at 4-month intervals (IPT n=3535, placebo n=3223). The primary endpoint was the prevalence of anaemia, defined as a haemoglobin concentration below 110 g/L. This outcome was assessed through cross-sectional surveys 12 months post-intervention. Analysis was by both intention to treat, excluding children with missing data, and per protocol. This study is registered with ClinicalTrials.gov, number NCT00142246.Findings2604 children in the IPT group and 2302 in the placebo group were included in the intention-to-treat analysis of the primary outcome; the main reason for exclusion was loss to follow-up. Prevalence of anaemia at 12 months averaged 6·3% in the IPT group and 12·6% in the placebo group (adjusted risk ratio 0·52, 95% CI 0·29–0·93; p=0·028). Significant improvements were also seen in two of the class-based tests of sustained attention, with a mean increase in code transmission test score of 6·05 (95% CI 2·83–9·27; p=0·0007) and counting sounds test score of 1·80 (0·19–3·41; p=0·03), compared with controls. No effect was shown for inattentive or hyperactive-compulsive behaviours or on educational achievement. The per-protocol analysis yielded similar results. 23 serious adverse events were reported within 28 days of any treatment (19 in the IPT group and four in the placebo group); the main side-effects were problems of balance, dizziness, feeling faint, nausea, and/or vomiting shortly after treatment.InterpretationIPT of malaria improves the health and cognitive ability of semi-immune schoolchildren. Effective malaria interventions could be a valuable addition to school health programmes.FundingGates Malaria Partnership, the Norwegian Education Trust Fund and multidonor Education Development Programme Fund of the World Bank, DBL Centre for Health Research and Development, and the Wellcome Trust.

SummaryThe epidemiology of malaria over small areas remains poorly understood, and this is particularly true for malaria during epidemics in highland areas of Africa, where transmission intensity is low and characterized by acute within and between year variations. We report an analysis of the spatial distribution of clinical malaria during an epidemic and investigate putative risk factors. Active case surveillance was undertaken in three schools in Nandi District, Western Kenya for 10 weeks during a malaria outbreak in May-July 2002. Household surveys of cases and age-matched controls were conducted to collect information on household construction, exposure factors and socio-economic status. Household geographical location and altitude were determined using a hand-held geographical positioning system and landcover types were determined using high spatial resolution satellite sensor data. Among 129 cases identified during the surveillance, which were matched to 155 controls, we identified significant spatial clusters of malaria cases as determined using the spatial scan statistic.Conditional multiple logistic regression analysis showed that the risk of malaria was higher in children who were underweight, who lived at lower altitudes, and who lived in households where drugs were not kept at home.

Invasive cervical cancer (ICC) is the leading cause of cancer-related death among women in developing countries. Population-based cytologic screening and early treatment does reduce morbidity and mortality associated with cervical cancer. Some of the factors related to the success of such a program include awareness about cervical cancer and its screening. The objective of this study was to assess knowledge and practice about cervical cancer and Pap smear testing among cervical cancer and noncancer patients using a structured questionnaire to obtain information. Fifty-one percent of the respondents were aware of cervical cancer while 32% knew about Pap smear testing. There were no significant differences in knowledge between cervical cancer and noncancer patients. Health care providers were the principal source of information about Pap testing (82%). Only 22% of all patients had had a Pap smear test in the past. Patients aware of cervical cancer were more likely to have had a Pap smear test in the past. The level of knowledge is low among ICC and noncancer patients. There is need to increase the level of knowledge and awareness about ICC and screening among Kenyan women to increase uptake of the currently available hospital screening facilities.

Data on the prevalence of human papillomavirus (HPV) types in cervical carcinoma in women with HIV are scarce but are essential to elucidate the influence of immunity on the carcinogenicity of different HPV types, and the potential impact of prophylactic HPV vaccines in populations with high HIV prevalence. We conducted a multicentre case-case study in Kenya and South Africa. During 2007-2009, frozen tissue biopsies from women with cervical carcinoma were tested for HPV DNA using GP51/61-PCR assay. One hundred and six HIV-positive (mean age 40.8 years) and 129 HIV-negative women (mean age 45.7) with squamous cell carcinoma were included. Among HIV-positive women, the mean CD4 count was 334 cells/lL and 48.1% were on combined antiretroviral therapy. HIV-positive women had many more multiple HPV infections (21.6% of HPV-positive carcinomas) compared with HIV-negative women (3.3%) (p < 0.001) and the proportion of multiple infections was inversely related to CD4 level. An excess of HPV18 of borderline statistical significance was found in HIV-positive compared with HIVnegative cases (Prevalence ratio (PR) 5 1.9, 95% confidence interval (CI): 1.0-3.7, adjusted for study centre, age and multiplicity of infection). HPV16 and/or 18 prevalence combined, however, was similar in HIV-positive (66.7%) and HIVnegative cases (69.1%) (PR 5 1.0, 95% CI: 0.9-1.2). No significant difference was found for other HPV types. Our data suggest that current prophylactic HPV vaccines against HPV16 and 18 may prevent similar proportions of cervical SCC in HIVpositive as in HIV-negative women provided that vaccine-related protection is sustained after HIV infection. Infection with high-risk (HR) human papillomavirus (HPV)is a necessary cause for invasive cervical carcinoma. Worldwide HPV16 and 18 are found in 57% and 16% of cervical carcinomas, respectively, according to the findings of a recent meta-analysis 1 and are targeted by the current prophylactic HPV vaccines for cervical carcinoma prevention. HIV-positive women are at increased risk for HPV infection and progression to cervical intraepithelial neoplasia grade 3 (CIN3). 2Linkage studies between HIV/AIDS and cancer registries have shown a 2-to 22-fold increased invasive cervical carcinoma incidence in HIV-positive women compared with the general female population from the same area, depending upon the life expectancy of HIV-positive women and the coverage and quality of cervical cancer screening in different countries. 3,4 HPV16 infection and HPV16-associated precancerous lesions were reported to be less dependent on a woman's immune status compared with other HR HPV types.5 Indeed, a meta-analysis of HPV prevalence in HIV-positive women worldwide showed a relative underrepresentation of HPV16 and overrepresentation of the other HR HPV types in HIVpositive compared with HIV-negative women with or without cervical abnormalities. 6 The lower prevalence of HPV16 in CIN2/3 (the endpoint lesions used in the evaluation of HPV vaccine efficacy) raised the fear that vaccination may preven...

SummaryWe conducted a longitudinal study among 827 pregnant women in Nyanza Province, western Kenya, to determine the effect of earth-eating on geohelminth reinfection after treatment. The women were recruited at a gestational age of 14-24 weeks (median: 17) and followed up to 6 months postpartum. The median age was 23 (range: 14-47) years, the median parity 2 (range: 0-11). After deworming with mebendazole (500 mg, single dose) of those found infected at 32 weeks gestation, 700 women were uninfected with Ascaris lumbricoides, 670 with Trichuris trichiura and 479 with hookworm. At delivery, 11.2%, 4.6% and 3.8% of these women were reinfected with hookworm, T. trichiura and A. lumbricoides respectively. The reinfection rate for hookworm was 14.8%, for T. trichiura 6.65, and for A. lumbricoides 5.2% at 3 months postpartum, and 16.0, 5.9 and 9.4% at 6 months postpartum. There was a significant difference in hookworm intensity at delivery between geophagous and non-geophagous women (P ¼ 0.03). Women who ate termite mound earth were more often and more intensely infected with hookworm at delivery than those eating other types of earth (P ¼ 0.07 and P ¼ 0.02 respectively). There were significant differences in the prevalence of A. lumbricoides between geophagous and non-geophagous women at 3 (P ¼ 0.001) and at 6 months postpartum (P ¼ 0.001). Women who ate termite mound earth had a higher prevalence of A. lumbricoides, compared with those eating other kinds of earth, at delivery (P ¼ 0.02), 3 months postpartum (P ¼ 0.001) and at 6 months postpartum (P ¼ 0.001).The intensity of infections with T. trichiura at 6 months postpartum was significantly different between geophagous and non-geophagous women (P ¼ 0.005). Our study shows that geophagy is associated with A. lumbricoides reinfection among pregnant and lactating women and that intensities built up more rapidly among geophagous women. Geophagy might be associated with reinfection with hookworm and T. trichiura, although these results were less unequivocal. These findings call for increased emphasis, in antenatal care, on the potential risks of earth-eating, and for deworming of women after delivery.

Anaemia is multi-factorial in origin and disentangling its aetiology remains problematic, with surprisingly few studies investigating the relative contribution of different parasitic infections to anaemia amongst schoolchildren. We report cross-sectional data on haemoglobin, malaria parasitaemia, helminth infection and undernutrition among 1523 schoolchildren enrolled in classes 5 and 6 (aged 10–21 years) in 30 primary schools in western Kenya. Bayesian hierarchical modelling was used to investigate putative relationships. Children infected with Plasmodium falciparum or with a heavy Schistosoma mansoni infection, stunted children and girls were found to have lower haemoglobin concentrations. Children heavily infected with S. mansoni were also more likely to be anaemic compared with uninfected children. This study further highlights the importance of malaria and intestinal schistosomiasis as contributors to reduced haemoglobin levels among schoolchildren and helps guide the implementation of integrated school health programmes in areas of differing parasite transmission.