IntroductionDeployment of rotavirus vaccines has contributed to significant declines in diarrheal morbidity and mortality globally. Unfortunately, vaccine performance in low-middle income countries (LMICs) is generally lower than in developed countries. The cause for this has been associated with several host and maternal factors including poor water sanitation and hygiene (WASH) status, which are predominant in LMICs. More recently, environmental enteric dysfunction (EED) has specifically been hypothesized to contribute to poor vaccine uptake and response. The aim of this study was to examine the association between serological biomarkers of EED and seroconversion to rotavirus vaccine in Zambian infants.MethodsThis was a retrospective cohort study of 142 infants who had been fully immunized with Rotarix™, and had known seroconversion status. Seroconversion was defined as 4-fold or more increase in rotavirus-specific IgA titres between pre-vaccination and one month post-dose two vaccination. We performed ELISA assays to assess soluble CD14 (sCD14), Endotoxin Core IgG Antibodies (EndoCAb), intestinal fatty acid binding protein (i-FABP) and Zonulin according to the manufacturers protocols. Generalised linear model with family-poisson, link-log and robust standard error was used to estimate the independent effects of biomarkers on seroconversion adjusting for important cofounders.ResultsThe median concentration of Zonulin, Soluble CD14, EndoCaB, and IFABP were 209.3 (IQR = 39.7, 395.1), 21.5 (IQR = 21.5, 21.5), 0.3 (IQR = 0.3, 0.3), and 107.7 (IQR = 6.4, 1141.4) respectively. In multivariable analyses adjusting for the independent effect of other biomarkers and confounders (i.e. age of child at vaccination, breast-milk anti-rotavirus IgA, infant serum anti-rotavirus IgG, and IgA seropositivity at baseline), there was strong evidence of about 24% increase in seroconversion due to doubling Zonulin concentration (Adjusted risk ratio (aRR) = 1.24; 95% CI = 1.12 to1.37; p<0.0001). Similarly, we found about 7% increase in seroconversion due to doubling IFABP concentration (aRR = 1.07; 95% CI = 1.02 to 1.13; p = 0.006).ConclusionWe found that high levels of zonulin and IFABP played a role in seroconversion. It is plausible that increased gut permeability in EED allows greater uptake of the live virus within the vaccine, but later consequences result in deleterious local structural distortions and malabsorption syndromes.

ObjectiveImmune activation is associated with morbidity and mortality during human immunodeficiency virus (HIV) infection, despite receipt of antiretroviral therapy (ART). We investigated whether microbial translocation drives immune activation in HIV-infected Ugandan children.MethodsNineteen markers of immune activation and inflammation were measured over 96 weeks in HIV-infected Ugandan children in the CHAPAS-3 Trial and HIV-uninfected age-matched controls. Microbial translocation was assessed using molecular techniques, including next-generation sequencing.ResultsOf 249 children included, 142 were infected with HIV; of these, 120 were ART naive, with a median age of 2.8 years (interquartile range [IQR], 1.7–4.0 years) and a median baseline CD4+ T-cell percentage of 20% (IQR, 14%–24%), and 22 were ART experienced, with a median age of 6.5 years (IQR, 5.9–9.2 years) and a median baseline CD4+ T-cell percentage of 35% (IQR, 31%–39%). The control group comprised 107 children without HIV infection. The median increase in the CD4+ T-cell percentage was 17 percentage points (IQR, 12–22 percentage points) at week 96 among ART-naive children, and the viral load was <100 copies/mL in 76% of ART-naive children and 91% of ART-experienced children. Immune activation decreased with ART use. Children could be divided on the basis of immune activation markers into the following 3 clusters: in cluster 1, the majority of children were HIV uninfected; cluster 2 comprised a mix of HIV-uninfected children and HIV-infected ART-naive or ART-experienced children; and in cluster 3, the majority were ART naive. Immune activation was low in cluster 1, decreased in cluster 3, and persisted in cluster 2. Blood microbial DNA levels were negative or very low across groups, with no difference between clusters except for Enterobacteriaceae organisms (the level was higher in cluster 1; P < .0001).ConclusionImmune activation decreased with ART use, with marker clustering indicating different activation patterns according to HIV and ART status. Levels of bacterial DNA in blood were low regardless of HIV status, ART status, and immune activation status. Microbial translocation did not drive immune activation in this setting.Clinical Trials RegistrationISRCTN69078957.

BackgroundThe burden, clinical features, and molecular epidemiology of norovirus infection in young children in southern Africa are not well defined.MethodsUsing data from a health facility-based surveillance study of children <5 years in Lusaka Province, Zambia presenting with diarrhea, we assessed the burden of norovirus infection. A convenience sample of 454 stool specimens was tested for norovirus using reverse-transcriptase polymerase chain reaction (RT-PCR). RT-PCR positive samples underwent additional nucleotide sequencing for genogroup and genotype identification. Clinical features and severity of diarrheal illnesses were compared between norovirus-positive and -negative subjects using Chi-squared and t-tests.ResultsNorovirus was detected in 52/454 (11.5%) specimens tested. Abdominal pain, fever, and vomiting were the most common presenting features in norovirus-associated illnesses. However, there were no significant differences in the clinical features of norovirus-positive compared to norovirus-negative illnesses. Of 43 isolates that were available for sequencing, 31 (72.1%) were genogroup II (GII) and 12 (27.9%) were genogroup I (GI). The distribution of genotypes was diverse.ConclusionsNoroviruses were detected in approximately 10% of young children with diarrhea in the Lusaka Province of Zambia, with GII representing the majority of infections. These findings support the role of norovirus in symptomatic diarrhea disease in Africa. Further studies are needed to confirm these observations and to evaluate prevention strategies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-017-2206-2) contains supplementary material, which is available to authorized users.

The ability to evaluate individual HIV-1 virions from the quasispecies of vertically infected infants was evaluated in a field setting at the Centre for Infectious Disease Research in Zambia. Infant heel-prick blood specimens were spotted onto dried blood spot (DBS) filter paper cards at government health clinics. Nucleic acid was extracted and used as a template for HIV-1 proviral DNA detection by a commercial Amplicor HIV-1 PCR test (Roche, version 1.5). On samples that tested positive by commercial diagnostic assay, amplification of DNA was performed using an in-house assay of the 5′ and 3′ region of the HIV-1 genome. Additionally, fragments covering 1200 nucleotides within pol (full length protease and partial reverse transcriptase) and 1400 nucleotides within env (variable 1-variable 5 region) were further analyzed by single genome amplification (SGA). In summary, we have demonstrated an in-house assay for amplifying the 5′ and 3′ proviral HIV-1 DNA as well as pol and env proviral DNA fragments from DBS cards collected and analyzed entirely in Zambia. In conclusion, this study shows the feasibility of utilizing DBS cards to amplify the whole proviral HIV-1 genome as well as perform SGA on key HIV-1 genes.