Association between genital schistosomiasis and HIV in rural Zimbabwean women

OBJECTIVE: To determine the association between female genital Schistosoma haematobium infection and HIV. DESIGN AND METHODS: A cross-sectional study with a 1-year follow-up. Gynecological and laboratory investigations were performed for S. haematobium and HIV. Sexually transmitted infections, demographic and urogenital history were analysed as confounders. The participants were 527 sexually active, non-pregnant, non-menopausal women between the ages of 20 and 49 years. The setting was a rural Zimbabwean community where S. haematobium related lesions were found in 46% of the women, HIV in 29% and herpes simplex type- 2 (HSV-2) in 65%. RESULTS: In permanent residents (>3 years residency), HIV was found in 41% (29/70) of women with laboratory proven genital schistosomiasis as opposed to 26% HIV positive (96/375) in the schistosomal ova negative group [odds ratio (OR), 2.1; 95% confidence interval (CI), 1.2-3.5; P = 0.008. In multivariate analysis S. haematobium infection of the genital mucosa was significantly associated with HIV seropositivity (adjusted OR, 2.9; 95% CI, 1.11-7.5; P = 0.030). All seven women who became HIV positive during the study period (seroincidence 3.1%) had signs of S. haematobium at baseline. In accordance with other studies HIV was significantly associated with HSV-2 (OR, 3.0; 95% CI, 1.7-5.3; P < 0.001), syphilis and human papillomavirus. The highest HIV prevalence (45%) was found in the 25-29 years age group. CONCLUSION: Women with genital schistosomiasis had an almost three-fold risk of having HIV in this rural Zimbabwean community. Prospective studies are needed to confirm the association.     

Urogenital schistosomiasis in women of reproductive age in Tanzania's Lake Victoria region

We conducted a community-based study of 457 women aged 18-50 years living in eight rural villages in northwest Tanzania. The prevalence of female urogenital schistosomiasis (FUS) was 5% overall but ranged from 0% to 11%. FUS was associated with human immunodeficiency virus (HIV) infection (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 1.2-13.5) and younger age (OR = 5.5 and 95% CI = 1.2-26.3 for ages < 25 years and OR = 8.2 and 95% CI = 1.7-38.4 for ages 25-29 years compared with age > 35 years). Overall HIV prevalence was 5.9% but was 17% among women with FUS. We observed significant geographical clustering of schistosomiasis: northern villages near Lake Victoria had more Schistosoma mansoni infections (P < 0.0001), and southern villages farther from the lake had more S. haematobium (P = 0.002). Our data support the postulate that FUS may be a risk factor for HIV infection and may contribute to the extremely high rates of HIV among young women in sub-Saharan Africa.     

The role of maternal syphilis, gonorrhoea and HIV-1 infections in spontaneous abortion.

The role of the human immunodeficiency virus (HIV) and other sexually transmitted diseases (STDs) as risk factor for spontaneous abortion was investigated in a case-control study in Nairobi, Kenya. Cases (n = 195) were women admitted with clinical signs and symptoms of spontaneous abortion, before 20 weeks of gestation. Patients with induced or clinically septic abortion were excluded. Controls were unselected pregnant women in their second or third trimester (n = 195). Spontaneous abortion was independently associated with maternal HIV-1 antibody (14.4% versus 6.2%; adjusted odds ratio, 2.3; 95% confidence interval, 1.1-4.8), with maternal syphilis seroreactivity (6.8% vs 2.1%, adjusted odds ratio, 4.3; 95% confidence interval 1.2-15.6), and with vaginal colonization with group B streptococci (15.6% vs 5.2%; adjusted odds ratio, 3.2; 95% confidence interval, 1.5-6.7). No significant association was found between maternal infections with gonococci and genital mycoplasmas, and spontaneous abortion.     

The effects of maternal helminth and malaria infections on mother-to-child HIV transmission

OBJECTIVE: To investigate the effect of helminth and/or malaria infection on the risk of HIV infection in pregnant women and its transmission to their offspring. DESIGN: A retrospective cohort study of pregnant Kenyan women and their offspring from term, uncomplicated vaginal deliveries (n = 936) with a nested case-control study. METHODS: We determined the presence of HIV, malaria, schistosomiasis, lymphatic filariasis, and intestinal helminthes in mothers and tested for HIV antibodies in 12-24 month-old offspring of HIV-positive women. We related these findings to the presence of cord blood lymphocyte activation and cytokine production in response to helminth antigens. RESULTS: HIV-positive women (n = 83, 8.9% of all women tested) were 2-fold more likely to have peripheral blood and/or placental malaria (P < 0.025) and a 2.1-fold greater likelihood of lymphatic filariasis infection (P < 0.001) compared to location-and-parity matched HIV-negative women. Women with HIV and malaria tended to show an increased risk for mother-to-child-transmission (MTCT) of HIV, although this difference was not significant. MTCT of HIV, however, was significantly higher in women co-infected with one or more helminthes (48%) verses women without helminth infections (10%, P < 0.01; adjusted odds ratio, 7.3; 95% confidence interval, 2.4-33.7). This increased risk for MTCT of HIV correlated with cord blood lymphocytes production of interleukin-5/interleukin-13 in response to helminth antigens (P < 0.001). CONCLUSION: Helminth co-infection is associated with increased risk for MTCT of HIV, possibly by a mechanism in which parasite antigens activates lymphocytes in utero. Treatment of helminthic infections during pregnancy may reduce the risk of MTCT of HIV.     

Risk factors for hepatitis C virus infection in individuals infected with the HIV

BACKGROUND: Except for injecting drug use, other routes of transmission for hepatitis C virus among HIV-AIDS patients have not been consistently described, and risk estimates are often not adjusted for confounding factors. AIMS: To evaluate characteristics associated with hepatitis C virus infection in individuals infected with the HIV. PATIENTS: Cases were patients co-infected by HIV and hepatitis C virus, and controls were infected only by HIV. METHODS: Cases and controls were consecutively enrolled at a public health care outpatient HIV-AIDS reference centre in Porto Alegre, Southern Brazil. RESULTS: A total of 227 cases (63% men; 40.3+/-8.7 years) and 370 controls (44.6% men; 38.9+/-9.8 years) were enrolled in the study. In a multiple logistic regression model, male gender (odds ratio 1.9; 95% confidence interval 1.3-2.7), age between 30 and 49 years (odds ratio 2.1; 95% confidence interval 1.2-3.7), elementary school education (odds ratio 4.2; 95% confidence interval 1.9-9.6), lower family income (odds ratio 1.7; 95% confidence interval 1.1-2.7), sharing personal hygiene objects (odds ratio 2.0; 95% confidence interval 1.3-3.3), using injected drugs (odds ratio 21.6; 95% confidence interval 10.8-43.0) and crack cocaine (odds ratio 2.8; 95% confidence interval 1.1-6.9) were independently associated with co-infection by hepatitis C virus. CONCLUSION: These results confirm the risk profile for hepatitis C virus-HIV infection and suggest that sharing personal hygiene objects might explain the transmission of virus C to those not infected by the usual routes, which may be of relevance for developing preventive strategies.     

Schistosoma mansoni Morbidity among School-Aged Children: A SCORE Project in Kenya

Schistosomiasis control programs aim to reduce morbidity but are evaluated by infection prevalence and intensity reduction. We present baseline cross-sectional data from a nested cohort study comparing indicators of morbidity for measuring program impact. Eight hundred twenty-two schoolchildren 7–8 years of age from Nyanza Province, Kenya, contributed stool for diagnosis of Schistosoma mansoni and soil-transmitted helminths (STH) and blood smears for malaria, and were evaluated for anemia, quality of life, exercise tolerance, anthropometry, and ultrasound abnormalities. Schistosoma mansoni, STH, and malaria infection prevalence were 69%, 25%, and 8%, respectively. Only anemia and S. mansoni infection (adjusted odds ratio [aOR] = 1.70; confidence interval [CI] = 1.03–2.80), and hepatomegaly and heavy S. mansoni infection (aOR = 2.21; CI = 1.19–4.11) were associated. Though anemia and hepatomegaly appeared most useful at baseline, additional morbidity indicators may be sensitive longitudinal measures to evaluate schistosomiasis program health impact.     

Plasmodium falciparum and helminth coinfection in a semi urban population of pregnant women in Uganda

BACKGROUND: Helminth infections and malaria are widespread in the tropics. Recent studies suggest helminth infections may increase susceptibility to Plasmodium falciparum infection. If confirmed, this increased susceptibility could be particularly important during pregnancy-induced immunosuppression. OBJECTIVE: To evaluate the geographical distribution of P. falciparum-helminth coinfection and the associations between P. falciparum infection and infection with various parasite species in pregnant women in Entebbe, Uganda. METHODS: A cross-sectional study was conducted at baseline during a trial of antihelminthic drugs during pregnancy. Helminth and P. falciparum infections were quantified in 2,507 asymptomatic women. Subjects' socioeconomic and demographic characteristics and geographical details were recorded. RESULTS: Hookworm and Mansonella perstans infections were associated with P. falciparum infection, but the effect of hookworm infection was seen only in the absence of M. perstans infection. The odds ratio [OR] for P. falciparum infection, adjusted for age, tribe, socioeconomic status, HIV infection status, and location was as follows: for individuals infected with hookworm but not M. perstans, 1.53 (95% confidence interval [CI], 1.09-2.14); for individuals infected with M. perstans but not hookworm, 2.33 (95% CI, 1.47-3.69); for individuals infected with both hookworm and M. perstans, 1.85 (CI, 1.24-2.76). No association was observed between infection with Schistosoma mansoni, Trichuris, or Strongyloides species and P. falciparum infection. CONCLUSIONS: Hookworm-P. falciparum coinfection and M. perstans-P. falciparum coinfection among pregnant women in Entebbe is more common than would be expected by chance. Further studies are needed to elucidate the mechanism of this association. A helminth-induced increase in susceptibility to P. falciparum could have important consequences for pregnancy outcome and responses to P. falciparum infection in infancy.     

Family history of hypertension and type 2 diabetes in relation to preeclampsia risk

In a case-control study of 190 preeclamptic patients and 373 control subjects, we assessed maternal family history of chronic hypertension and type 2 diabetes in relation to preeclampsia risk. Participants provided information on first-degree family history of the 2 conditions and other covariates during postpartum interviews. Logistic regression was used to estimate odds ratios and 95% confidence intervals adjusted for confounding by age, race, and obesity. Compared with women with no parental history of hypertension, women with maternal only (odds ratio=1.9), paternal only (odds ratio=1.8), or both maternal and paternal history of hypertension (odds ratio=2.6) had a statistically significant increased risk of preeclampsia. The odds ratio for women with at least one hypertensive parent and a hypertensive sibling was 4.7 (95% confidence interval, 1.9 to 11.6). Both maternal only (odds ratio=2.1; 95% confidence interval, 0.9 to 4.6) and paternal only (odds ratio=1.9; 95% confidence interval, 1.0 to 3.2) history of diabetes was associated with an increased risk of preeclampsia. Women with a diabetic sibling had a 4.7-fold increased risk of preeclampsia (95% confidence interval, 1.1 to 19.8). For women with at least one hypertensive parent and at least one diabetic parent, relative to those with parents with neither diagnosis, the odds ratio for preeclampsia was 3.2 (95% confidence interval, 1.6 to 6.2). Our results are consistent with the thesis that family history of hypertension and diabetes reflects genetic and behavioral factors whereby women may be predisposed to an increased preeclampsia risk.     

Risk factors for HIV infection among asymptomatic pregnant women attending an antenatal clinic in western Kenya

Our objective was to evaluate HIV prevalence and identify risk factors for HIV infection among women attending the antenatal clinic (ANC) at a large public hospital in Kisumu town, western Kenya. Between June 1996 and November 1997, in the context of a study to determine the effect of placental malaria on mother-to-child transmission of HIV in western Kenya, HIV-1 antibody testing was offered to women with a singleton uncomplicated pregnancy of > or =32 weeks' gestation attending the ANC. Women were interviewed using a structured questionnaire and had a fingerstick blood sample collected for haemoglobin (Hb), malaria smears, and HIV antibody testing. Overall HIV seroprevalence was 26.1% (743/2844) (95% confidence interval (CI): 24.5-27.7) and in bivariate evaluation was significantly associated with anaemia (Hb <11 g/dl) (risk ratio (RR) 1.8), malarial parasitaemia (RR 1.6), fever (axillary temperature > or =37.5 degrees C at screening) (RR 1.6), a history of being treated for either vaginal discharge (RR 1.5) or tuberculosis (RR 1.6), reported alcohol consumption (RR 1.6), being an unmarried multigravida (RR 2.2) or a history of the most recent child having died (RR 2.0). Poisson regression analysis for all women identified 5 significant factors independently associated with HIV seropositivity: anaemia (adjusted RR 1.7; 95% CI 1.3-2.0), malarial parasitaemia (adjusted RR 1.7; 95% CI 1.4-2.0), a history of being treated for vaginal discharge (adjusted RR 1.5; 95% CI 1.1-2.0), fever (adjusted RR 2.0; 95% CI 1.3-3.2) and reported alcohol consumption (adjusted RR 1.6; 95% CI 1.1-2.5). Multigravidae women whose most recent child had died were also more likely to be HIV seropositive (adjusted RR 1.9; 95% CI 1.7-2.8). Only 5.5% (156/2844) of the women had none of these risk factors, of whom 12% (18/156) were HIV(+). Even though the model containing the 5 identified factors fitted the data well (goodness-of-fit chi2=18.41, P=0.10), its collective capacity to predict HIV infection was poor; while 74% of the truly positive women were correctly predicted positive by the model, 52% of the truly negative women were misclassified. Among pregnant women attending the ANC in western Kenya, we were unable to identify a subgroup at risk of HIV infection using non-serological information, indicating that wherever possible universal access to voluntary HIV counselling and testing would be preferable to targeted screening.     

Effects of HIV-1 serostatus, HIV-1 RNA concentration, and CD4 cell count on the incidence of malaria infection in a cohort of adults in rural Malawi

BACKGROUND: To assess the effects of human immunodeficiency virus (HIV) infection on susceptibility to malaria, we compared the incidence rates of malaria by HIV type 1 (HIV-1) serostatus, baseline blood HIV-1 RNA concentration, and baseline CD4 cell count, over the course of a malaria season. METHODS: We followed a cohort of 349 adults in Malawi. For the 224 HIV-1-seropositive adults (64% of the cohort), we measured HIV-1 RNA concentration (n=187) and CD4 cell count (n=184) at baseline. Parasitemia was defined as presence of asexual parasites on a thick film of blood and was treated with sulfadoxine/pyrimethamine (SP), in accordance with national policy. Hazard ratios (HRs) of parasitemia were estimated using Cox regression. Demographics were adjusted for. RESULTS: HIV-1 seropositivity was associated with parasitemia (adjusted HR, 1.8 [95% confidence interval {CI}, 1.2-2.7] for a first parasitemia episode; adjusted HR, 2.5 [95% CI, 1.5-4.2] for a second parasitemia episode [> 14 days after the first episode]; adjusted HR, 1.9 [95% CI, 1.4-2.6] for parasitemia overall). Treatment failure (parasitemia < or = 14 days after SP treatment) did not differ by HIV-1 serostatus (risk ratio, 1.3 [95% CI, 0.5-3.2]). HIV-1 RNA concentrations and CD4 cell counts were moderately but inconsistently associated with parasitemia. A high parasite density with fever was associated with HIV-1 seropositivity and low CD4 cell count. CONCLUSION: HIV-infected adults in malaria-endemic areas are at increased risk for malaria. Where possible, additional malaria prevention efforts should be targeted at this population.     

Association between Schistosoma mansoni and hookworm infections among schoolchildren in Côte d'Ivoire

Infections with Schistosoma mansoni and hookworms are widespread in sub-Saharan Africa and the burden of disease associated with both parasites is enormous. Although there is a large overlap in their geographic distribution, little is known about the association between S. mansoni and hookworm infections and the underlying mechanisms. We explored this association among 325 schoolchildren from C?te d'Ivoire, by screening multiple stool specimens over consecutive days. We found a highly significant positive association between S. mansoni and hookworm infections with an adjusted odds ratio of 2.25 (95% confidence interval: 1.31-3.85; P=0.003). Increasing infection intensity of S. mansoni was significantly correlated with an increased likelihood of concomitant hookworm infections (chi(2)=20.72; P<0.001). Egg counts in stool specimens derived from a single day did not consistently reveal the positive association between the two parasites, which underlines the importance of repeated stool examinations. Several self-reported water contact patterns were significantly associated either with S. mansoni, hookworm or concomitant infections. Our findings are of considerable importance for tailoring effective health education messages that are readily adapted to the local epidemiological setting. Complemented with other control interventions, these measures might significantly reduce the burden caused by S. mansoni and hookworm infections.     

Patterns and Risk Factors of Soil-Transmitted Helminthiasis among Orang Asli Subgroups in Peninsular Malaysia

A cross-sectional study was conducted to provide comprehensive data on the patterns and associated risk factors of soil-transmitted helminth (STH) infections among five Orang Asli subgroups in Peninsular Malaysia. The overall prevalence of STH infections was 59.9% (95% confidence interval [CI] = 56.1–63.7%). Trichuris trichiura (54.3%; 95% CI = 50.4–58.2%) was the predominant species followed by Ascaris lumbricoides (26.7%; 95% CI = 23.3–30.1%) and hookworm (9.1%; 95% CI = 6.9–11.3%). This study showed diversity for STH infections by subgroup with poverty and personal sanitary behavior as important risk factors for infection. Risk profile analyses indicating that Orang Kuala subgroup who has a generally well-developed infrastructure and better quality of life had a low rate of infection. There is a need for poverty reduction and promotion of deworming programs along with mass scale campaigns to create awareness about health and hygiene to reduce STH infections.     

Placental malaria and mother-to-child transmission of human immunodeficiency virus-1 in rural Rwanda

We conducted a nested case-control study of placental malaria (PM) and mother-to-child transmission (MTCT) of human immunodeficiency virus-1 (HIV-1) within a prospective cohort of 627 mother-infant pairs followed from October 1989 until April 1994 in rural Rwanda. Sixty stored placentas were examined for PM and other placental pathology, comparing 20 HIV-infected mother-infant (perinatal transmitter) pairs, 20 HIV-uninfected pairs, and 20 HIV-infected mothers who did not transmit to their infant perinatally. Of 60 placentas examined, 45% showed evidence of PM. Placental malaria was associated with increased risk of MTCT of HIV-1 (adjusted odds ratio [aOR] = 6.3; 95% confidence interval [CI] = 1.4-29.1), especially among primigravidae (aOR = 12.0; 95% CI = 1.0-150; P < 0.05). Before antiretroviral therapy or prophylaxis, PM was associated with early infant HIV infection among rural Rwandan women living in a hyper-endemic malaria region. Primigravidae, among whom malaria tends to be most severe, may be at higher risk.     

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

BACKGROUND: In sub-Saharan Africa, co-infection with HIV and malaria is probably very common. Although an interaction between the two infections is biologically plausible, it has not been investigated thoroughly. OBJECTIVES: To evaluate the association firstly between co-infection with HIV and malaria parasites and the occurrence of acute fever, and secondly between HIV infection and clinical malaria, defined as the presence of acute fever and malaria parasites. METHODS: A hospital-based case-control study was conducted in Gulu District (northern Uganda), an area endemic for malaria and with a high HIV prevalence. HIV testing and malaria parasite quantification were performed on 167 consecutive adult out-patients with acute fever and no signs or symptoms of localized infection, and on 134 consecutive adult in-patients without fever who were admitted for non-HIV-related trauma or elective surgery. RESULTS: No significant association with acute fever was observed for single infection with either malaria parasites [adjusted odds ratio (AOR), 1.75; 95% confidence interval (CI), 0.73-4.21] or HIV (AOR, 1.01; 95% CI, 0.51-2.03), whereas a significant association was observed for co-infection (AOR, 9.75; 95% CI, 1.19-80.00). An association was found between HIV infection and clinical malaria (AOR, 2.34; 95% CI, 0.89-6.17); the association became statistically significant when the definition of clinical malaria included a cut-off for parasite density (50th percentile; i.e., 586 parasites/microl; AOR, 3.61; 95% CI, 1.04-12.52). CONCLUSIONS: Despite the limited statistical power, the results of our study show an association between HIV infection and clinical malaria; if confirmed, this finding could be important for public health in sub-Saharan Africa.     

Secretor polymorphism and human immunodeficiency virus infection in Senegalese women

The FUT2 gene encodes the enzyme alpha (1,2) fucosyltransferase, which determines expression of blood-group antigens on mucosal epithelial cell surfaces and in secretions. Homozygotes for a specific stop mutation in FUT2 (nonsecretors) cannot produce this enzyme and thus are unable to express blood group antigens. Nonsecretor status is associated with a decreased risk of several respiratory viral infections. By use of molecular genotyping, 2 populations of Senegalese women were examined for polymorphisms of the FUT2 gene. Among Senegalese commercial sex workers, absence of FUT2 (nonsecretor genotype) was associated with reduced risk of human immunodeficiency virus (HIV) type 1 infection (odds ratio [OR] adjusted for cervical and vaginal infection, 0.18; 95% confidence interval [CI], 0.04-0.90) and HIV-2 infection (adjusted OR, 0.43; 95% CI, 0.13-1.39), although the latter was not statistically significant. Modification of cell surface carbohydrates at mucosal surfaces determined by the FUT2 gene may underlie the protective association against heterosexual HIV infection.     

HIV infection as a cofactor for severe falciparum malaria in adults living in a region of unstable malaria transmission in South Africa

BACKGROUND: Malaria and HIV are two of the most important diseases facing Africa. It remains uncertain whether HIV-related immunosuppression adversely affects the clinical outcome of malaria. OBJECTIVE: To measure the association between HIV status and outcome from malarial infection in adults living in a region of unstable malaria transmission. DESIGN: Observational cohort study. SETTING: Four community clinics and the Government hospital in Hlabisa district, KwaZulu-Natal, South Africa; a region of high HIV prevalence. METHODS: Consecutive febrile adults were screened for malaria with a rapid antigen test. Those with malaria provided blood spots for HIV testing, a thick blood film for confirmation of malaria and clinical data. Outcome was established following management according to South African government guidelines. RESULTS: Malaria was microscopically confirmed in 613. HIV prevalence was 29.9% (180/613); 110 (18%) had severe/complicated malaria and 28 (4.6%) died. HIV-infected patients were more likely to vomit or be confused and were more likely to be admitted to hospital (P = 0.05). In patients admitted to hospital, HIV infection was associated with severe/complicated malaria [adjusted odds ratio (OR) 2.3; 95% confidence interval (CI), 1.4-3.9] and with death (OR 7.5; 95% CI, 2.2-25.1). Acidosis and coma were also strong independent risk factors for death. CONCLUSION: HIV infection had an unexpectedly large association with the outcome of falciparum malaria in a region of unstable transmission. Both diseases are widespread in Africa and these results add to the body of knowledge suggesting an interaction of significant public health importance between HIV and malaria in Africa.     

Trichuris and hookworm infections associated with anaemia during pregnancy

Objective To assess the following associations between the second and third trimesters of pregnancy: (i) the intensity of soil‐transmitted helminth (STH) infection and haemoglobin/anaemia, (ii) the effect of mebendazole treatment on the occurrence of STH infection, and (iii) the effect of mebendazole treatment on haemoglobin/anaemia. Methods Data originated from a trial of 1042 pregnant women recruited in their second trimester and followed to delivery. Baseline assessments included socio‐demographic/health information from questionnaires, haemoglobin/anaemia from HemoCue ascertainment of fingerprick blood, and the presence and intensity of STH (Ascaris lumbricoides, hookworms and Trichuris trichiura) infections from Kato–Katz examination. All women were given iron supplements; half were randomly allocated to receive single dose 500 mg mebendazole, and half, placebo. Haemoglobin/anaemia and STH infection status were determined again in the third trimester of pregnancy. Results Complete information was available from 935 (89.7%) women. Mebendazole significantly reduced the prevalence and intensity of all three STH infections. Higher intensities of hookworm and Trichuris infections in the second trimester were associated with a higher risk of anaemia in the third trimester. Overall, women with moderate/heavy Trichuris infection were found to be at a higher risk of anaemia; the highest risk was observed among those with moderate/heavy hookworm co‐infection (adjusted OR = 2.77; 95% CI: 1.26, 6.11). Mebendazole treatment did not reduce the risk of anaemia. Conclusion Higher intensities of both Trichuris and hookworm infections are associated with anaemia in pregnancy. The importance of Trichuris infections during pregnancy requires renewed attention.     

Wheezing,allergy, and parasite infection in children in urban and rural Ethiopia

Epidemiological studies in developing countries suggest that intestinal parasite infection may reduce the risk of asthma. Because this evidence is all derived from adults and older children, we have investigated the relation between parasite infection, wheezing, and allergen skin sensitization in nested case-control studies drawn from a survey of 7,155 children aged 1 to 4 years living in urban and rural areas of Jimma, Ethiopia. Infection with parasites was common, predominantly with Trichuris (54%), Ascaris (38%), and hookworm (10%). Wheezing in the past year was significantly more prevalent in urban (4.4%) than rural children (2.0%), and was less prevalent in those infected with Ascaris (age, sex, and urban/rural adjusted odds ratio, 0.5; 95% confidence interval, 0.3 to 0.9), particularly in relation to high-intensity infection. Similar, although nonsignificant, associations were found for hookworm (adjusted odds ratio, 0.6; 95% confidence interval, 0.2 to 1.8), but there was no suggestion of any relation to Trichuris infection. Dermatophagoides pteronyssinus and cockroach (Blattella germanica) skin sensitization was more prevalent in rural than urban children, and was unrelated to wheeze. We conclude that Ascaris and possibly hookworm infection protects against wheeze in young Ethiopian children, and that this effect is not mediated by inhibition of allergen sensitization.     

Concurrent urinary and intestinal schistosomiasis and intestinal helminthic infections in schoolchildren in Ilobu, South-western Nigeria

A cross-sectional study was conducted in a schistosome-endemic rural community in Southwestern Nigeria. We assessed prevalence and intensity of soil-transmitted nematodes and the co-occurrence with Schistosoma haematobium and Schistosoma mansoni. Urine and stool samples from 419 schoolchildren were examined, and a questionnaire was administered to obtain socio-demographic characteristics. In total, 78.3% (328/419) were infected with at least one helminth species, with a prevalence (mean egg-count) of 55.1% (3069.2) of Ascaris lumbricoides, 41.1% (127.5) of S. haematobium, 22.7% (98.6) of hookworms, 17.9% (161.3) of Trichuris trichiura, and 10.3% (12.9) of S. mansoni. Multiple infections were significantly more common among children from households with more playmates, absence of toilet facilities and low income level (all p<0.001). Children with heavy hookworm burden were at a significantly higher chance of acquiring S. mansoni (OR=36.35; 95% Cl: 13.22-100.97; p<0.0001). The risk of S. mansoni and A. lumbricoides infections was increased in co-infections with S. haematobium. Logistic regression analysis revealed infections by hookworms and S. mansoni (adjusted odds ratio [aOR]=3.90, 95% Cl: 2.03-7.46; p<0.0001), and by hookworms and T. trichiura (aOR=2.46, 95% Cl: 1.44-4.22; p=0.001) as significant risk factors for multiple infections. Our study shows that polyparasitism is common in the study area. Focused interventions such as mass treatment with anthelminthics and health education are needed to improve the well-being of the affected population.     

Prevalence, incidence, and type-specific persistence of human papillomavirus in human immunodeficiency virus (HIV)-positive and HIV-negative women

Human immunodeficiency virus (HIV) infection and related immunosuppression are associated with excess risk for cervical neoplasia and human papillomavirus (HPV) persistence. Type-specific HPV infection was assessed at 6-month intervals for HIV-positive and HIV-negative women (median follow-up, 2.5 and 2.9 years, respectively). The type-specific incidence of HPV infection was determined, and risk factors for HPV persistence were investigated by statistical methods that accounted for repeated measurements. HIV-positive women were 1.8, 2.1, and 2.7 times more likely to have high-, intermediate-, and low-risk HPV infections, respectively, compared with HIV-negative women. In multivariate analysis, high viral signal, but not viral risk category, was independently associated with persistence among HIV-positive subjects (odds ratio [OR], 2.5; 95% confidence interval [CI], 2.1-2.9). Furthermore, persistence was 1.9 (95% CI, 1.5-2.3) times greater if the subject had a CD4 cell count <200 cells/microL (vs. >500 cells/microL). Thus, HIV infection and immunosuppression play an important role in modulating the natural history of HPV infection.