Breast Milk as a Potential Source of Epstein-Barr Virus Transmission Among Infants Living in a Malaria-Endemic Region of Kenya.

BACKGROUND: We previously reported that infants in Kenya were infected with Epstein-Barr virus (EBV) at <6 months of age, suggesting that mothers were the likely source of transmissible virus to the infant. In this study, we investigated whether breast milk contained infectious EBV and the role of malaria in EBV shedding in breast milk. METHODS: Breast milk samples were obtained from Kenyan mothers at postpartum weeks 6, 10, 14, and 18 and analyzed for presence of infectious EBV. RESULTS: We found that the prevalence of EBV DNA and the mean EBV load were significantly higher at 6 weeks and decreased through postpartum week 18 (P < .0001). High EBV load in breast milk correlated with mothers who had Plasmodium falciparum malaria at delivery. To determine whether viral DNA was encapsidated, breast milk samples were treated with DNAse before DNA extraction. Sixty percent of samples were DNAse resistant, suggesting that the viral DNA in breast milk was encapsidated. Next, we exposed peripheral blood mononuclear cells to breast milk supernatant, which resulted in the generation of EBV-positive lymphoblastoid cell lines, indicating that the virus in breast milk was infectious. CONCLUSIONS: Our data suggest that breast milk contains infectious EBV and is a potential source of viral transmission to infants living in malaria-endemic regions.

Plasmodium falciparum infection is associated with Epstein-Barr virus reactivation in pregnant women living in malaria holoendemic area of Western Kenya.

The role of Plasmodium falciparum malaria in Epstein-Barr virus (EBV) transmission among infants early in life remain elusive. We hypothesized that infection with malaria during pregnancy could cause EBV reactivation leading to high EBV load in circulation, which could subsequently enhance early age of EBV infection. Pregnant women in Kisumu, where P. falciparum malaria is holoendemic, were actively followed monthly through antenatal visits (up to 4 per mother) and delivery. Using real-time quantitative (Q)-PCR, we quantified and compared EBV and P. falciparum DNA levels in the blood of pregnant women with and without P. falciparum malaria. Pregnant women that had malaria detected during pregnancy were more likely to have detectable EBV DNA than pregnant women who had no evidence of malaria infection during pregnancy (64 vs. 36 %, p = 0.01). EBV load as analyzed by quantifying area under the longitudinal observation curve (AUC) was significantly higher in pregnant women with P. falciparum malaria than in women without evidence of malaria infection (p = 0.01) regardless of gestational age of pregnancy. Increase in malaria load correlated with increase in EBV load (p < 0.0001). EBV load was higher in third trimester (p = 0.04) than first and second trimester of pregnancy independent of known infections. Significantly higher frequency and elevated EBV loads were found in pregnant women with malaria than in women without evidence of P. falciparum infection during pregnancy. The loss of control of EBV latency following P. falciparum infection during pregnancy and subsequent increase in EBV load in circulation could contribute to enhanced shedding of EBV in maternal saliva and breast milk postpartum, but further studies are needed.

Factors associated with non-adherence to highly active antiretroviral therapy in Nairobi, Kenya.

BACKGROUND: Antiretroviral therapy (ART) requires high-level (> 95%) adherence. Kenya is rolling out ART access programmes and, issue of adherence to therapy is therefore imperative. However, published data on adherence to ART in Kenya is limited. This study assessed adherence to ART and identified factors responsible for non adherence in Nairobi. METHODS: This is a multiple facility-based cross-sectional study, where 416 patients aged over 18 years were systematically selected and interviewed using a structured questionnaire about their experience taking ART. Additional data was extracted from hospital records. Patients were grouped into adherent and non-adherent based on a composite score derived from a three questions adherence tool developed by Center for Adherence Support Evaluation (CASE). Multivariate regression model was used to determine predictors of non-adherence. RESULTS: Overall, 403 patients responded; 35% males and 65% females, 18% were non-adherent, and main (38%) reason for missing therapy were being busy and forgetting. Accessing ART in a clinic within walking distance from home (OR = 2.387, CI.95 = 1.155-4.931; p = 0.019) and difficulty with dosing schedule (OR = 2.310, CI.95 = 1.211-4.408, p = 0.011) predicted non-adherence. CONCLUSIONS: The study found better adherence to HAART in Nairobi compared to previous studies in Kenya. However, this can be improved further by employing fitting strategies to improve patients' ability to fit therapy in own lifestyle and cue-dose training to impact forgetfulness. Further work to determine why patients accessing therapy from ARV clinics within walking distance from their residence did not adhere is recommended.

Alterations on peripheral B cell subsets following an acute uncomplicated clinical malaria infection in children.

BACKGROUND: The effects of Plasmodium falciparum on B-cell homeostasis have not been well characterized. This study investigated whether an episode of acute malaria in young children results in changes in the peripheral B cell phenotype. METHODS: Using flow-cytofluorimetric analysis, the B cell phenotypes found in the peripheral blood of children aged 2-5 years were characterized during an episode of acute uncomplicated clinical malaria and four weeks post-recovery and in healthy age-matched controls. RESULTS: There was a significant decrease in CD19+ B lymphocytes during acute malaria. Characterization of the CD19+ B cell subsets in the peripheral blood based on expression of IgD and CD38 revealed a significant decrease in the numbers of naive 1 CD38-IgD+ B cells while there was an increase in CD38+IgD- memory 3 B cells during acute malaria. Further analysis of the peripheral B cell phenotype also identified an expansion of transitional CD10+CD19+ B cells in children following an episode of acute malaria with up to 25% of total CD19+ B cell pool residing in this subset. CONCLUSION: Children experiencing an episode of acute uncomplicated clinical malaria experienced profound disturbances in B cell homeostasis.

Concomitant infections of Plasmodium falciparum and Wuchereria bancrofti on the Kenyan coast.

BACKGROUND: Anopheles gambiae s.l. and An. funestus are important vectors of malaria and bancroftian filariasis, which occur as co-endemic infections along the Kenyan Coast. However, little is known about the occurrence and prevalence of concomitant infections of the two diseases in mosquito and human populations in these areas. This study reports the prevalence of concomitant infections of Plasmodium falciparum and Wuchereria bancrofti in mosquito and human populations in Jilore and Shakahola villages in Malindi, Kenya. METHODS: Mosquitoes were sampled inside houses by pyrethrum spray sheet collection (PSC) while blood samples were collected by finger prick technique at the end of entomological survey. RESULTS: A total of 1,979 female Anopheles mosquitoes comprising of 1,919 Anopheles gambiae s.l and 60 An. funestus were collected. Concomitant infections of P. falciparum sporozoites and filarial worms occurred in 1.1% and 1.6% of An. gambiae s.l collected in Jilore and Shakahola villages respectively. Wuchereria-infected mosquitoes had higher sporozoite rates compared to non-infected mosquitoes, but multiple infections appeared to reduce mosquito survivorship making transmission of such infections rare. None of the persons examined in Shakahola (n = 107) had coinfections of the two parasites, whereas in Jilore (n = 94), out of the 4.3% of individuals harbouring both parasites, 1.2% had P. falciparum gametocytes and microfilariae and could potentially infect the mosquito with both parasites simultaneously. CONCLUSION: Concerted efforts should be made to integrate the control of malaria and bancroftian filariasis in areas where they co-exist.

Relationship between malaria and filariasis transmission indices in an endemic area along the Kenyan Coast.

BACKGROUND AND OBJECTIVES: An entomological survey was conducted to determine the relationship between malaria and lymphatic filariasis transmission by Anopheles gambiae s.l. and An. funestus in two inland villages along the Kenyan coast. METHODS: Mosquitoes were sampled inside houses by pyrethrum spray sheet collection (PSC). In the laboratory, the mosquitoes were sorted to species, dissected for examination of filarial infection and the anophelines later tested for Plasmodium falciparum circumsporozoite proteins by an enzyme-linked immunosorbent assay (ELISA). RESULTS: From a total of 2,032 female mosquitoes collected indoors, An. gambiae s.l constituted 94.4% while the remaining 5.6% comprised of An. funestus and Culex quinquefasciatus. None of the Cx. quinquefasciatus was positive for filarial worms. P. falciparum sporozoite rate for An. gambiae s.l. from both villages was significantly higher than Wuchereria bancrofti infectivity rate. Similarly, the entomological inoculation rate for An. gambiae s.l. was significantly higher than the corresponding W. bancrofti infective biting rate and transmission potential for both the villages. Mass treatment of people with filaricidal drugs in Shakahola in the ongoing global elimination of lymphatic filariasis campaign seemed to have reduced the indices of filariasis transmission but had no effect on malaria transmission. INTERPRETATION AND CONCLUSION: These results indicate the intensity of malaria transmission by anophelines to be much higher than that of lymphatic filariasis in areas where both diseases co-exist and re-emphasise the need to integrate the control of the two diseases in such areas.

Factors influencing community participation in control and related operational research for urogenital schistosomiasis and soil-transmitted helminths in rural villages of Kwale County, coastal Kenya.

INTRODUCTION: helminthic infections caused by soil-transmitted helminths (STH) and schistosomes are among the most prevalent afflictions of humans who live in areas of poverty. An operational research was undertaken in 5 villages of Kwale County during a pilot control programme which included both the adults and school going children. Willingness of community members to participate in the treatment as well as in the research is critical. A cross sectional study sought to determine factors influencing community participation in control and related operational research and assess the treatment coverage for urogenital schistosomiasis and hookworms in rural villages of Kwale County. METHODS: cross-sectional survey utilized quantitative and qualitative methods of data collection. A total of 220 households were recruited and household heads interviewed. Bivariate analysis was used to test association between different independent and dependent factors. Multivariate analysis was done using binary logistic regression to control for confounders and effect modification. Qualitative data was transcribed, coded and analyzed thematically. RESULTS: religion and levels of income were significantly (P =0.04 and P = 0.026 respectively) associated with participation in the research and control programme, history of ever suffering from schistosomiasis and intestinal worms was found to be significantly (P = 0.008) associated with participation in the research. The study established that 82% (178) of the respondents received treatment for urogenital schistosomiasis and hookworms and 67% (146) of the respondents had participated in the research. CONCLUSION: this information will be useful in promoting health, enhancing learning and behaviour changes which will lead to increased community participation in similar disease control.

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.

Short report: Childhood coinfections with Plasmodium falciparum and Schistosoma mansoni result in lower percentages of activated T cells and T regulatory memory cells than schistosomiasis only.

Flow cytometric analyses were performed to evaluate HLA-DR (+) activated T lymphocytes (Tact; CD3 (+)/CD4 (+)/CD25(medium)) and T regulatory cells (Treg; CD3 (+)/CD4(+)/CD25(high)) in the circulation of children 8-10 years of age living in an area endemic for both Plasmodium falciparum and Schistosoma mansoni in western Kenya. Those children with only S. mansoni had a higher mean percentage of HLA-DR (+) Tact than those who were co-infected with these two intravascular parasites. The proportion of circulating Treg was comparable in children with only schistosomiasis and both schistosomiasis and malaria. However, the mean level of memory Treg (Treg expressing CD45RO (+)) in those with dual infections was lower than in children with schistosomiasis alone. These imbalances in Tact and Treg memory subsets in children infected with both schistosomiasis and malaria may be related to the differential morbidity or course of infection attributed to coinfections with these parasites.