Browsing by Author "Elliott, Alison M"

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Anthelminthic treatment during pregnancy is associated with increased risk of infantile eczema: randomised-controlled trial results
(John Wiley & Sons A/S, 2011) Mpairwe, Harriet; Webb, Emily L; Muhangi, Lawrence; Ndibazza, Juliet; Akishule, Denise; Nampijja, Margaret; Ngom-wegi, Sophy; Tumusime, Josephine; Jones, Frances M; Fitzsimmons, Colin; Dunne, David W.; Muwanga, Moses; Rodrigues, Laura C.; Elliott, Alison M
Background: Allergy is commoner in developed than in developing countries. Chronic worm infections show inverse associations with allergy, and prenatal exposures may be critical to allergy risk. Objective: To determine whether anthelminthic treatment during pregnancy increases the risk of allergy in infancy. Methods: A randomised, double-blind, placebo-controlled trial on treatment in pregnancy with albendazole versus placebo and praziquantel versus placebo was conducted in Uganda, with a 2 · 2 factorial design; 2507 women were enrolled; infants’ allergy events were recorded prospectively. The main outcome was doctor-diagnosed infantile eczema Results: Worms were detected in 68% of women before treatment. Doctor-diagnosed infantile eczema incidence was 10.4/100 infant years. Maternal albendazole treatment was associated with a significantly increased risk of eczema [Cox HR (95% CI), p: 1.82 (1.26–2.64), 0.002]; this effect was slightly stronger among infants whose mothers had no albendazole-susceptible worms than among infants whose mothers had such worms, although this difference was not statistically significant. Praziquantel showed no effect overall but was associated with increased risk among infants of mothers with Schistosoma mansoni [2.65 (1.16–6.08), interaction p = 0.02]. In a sample of infants, skin prick test reactivity and allergen-specific IgE were both associated with doctor-diagnosed eczema, indicating atopic aetiology. Albendazole was also strongly associated with reported recurrent wheeze [1.58 (1.13–2.22), 0.008]; praziquantel showed no effect. Conclusions: The detrimental effects of treatment suggest that exposure to maternal worm infections in utero may protect against eczema and wheeze in infancy. The results for albendazole are also consistent with a direct drug effect. Further studies are required to investigate mechanisms of these effects, possible benefits of worms or worm products in primary prevention of allergy, and the possibility that routine deworming during pregnancy may promote allergic disease in the offspring.
Assessing the external validity of a randomized controlled trial of anthelminthics in mothers and their children in Entebbe, Uganda
(BioMed Central, 2014) Millard, James D; Muhangi, Lawrence; Sewankambo, Moses; Ndibazza, Juliet; Elliott, Alison M; Webb, Emily L
The ‘external validity’ of randomized controlled trials is an important measure of quality, but is often not formally assessed. Trials concerning mass drug administration for helminth control are likely to guide public health policy and careful interpretation of their context is needed. We aimed to determine how representative participants in one such trial were of their community. We explore implications for trial interpretation and resulting public health recommendations. Methods: The trial assessed was the Entebbe Mother and Baby Study (EMaBS), a trial of anthelminthic treatment during pregnancy and early childhood. In a novel approach for assessing external validity, we conducted a two-stage cluster sample community survey within the trial catchment area and compared characteristics of potentially-eligible community children with characteristics of children participating in the trial. Results: A total of 173 children aged three to five-years-old were surveyed from 480 households. Of children surveyed, we estimated that mothers of 60% would have been eligible for recruitment, and of these, 31% had actually been enrolled. Children surveyed were compared to 199 trial children in the same age group reviewed at annual trial visits during the same time period. There were significant differences in ethnicity between the trial participants and the community children, and in socioeconomic status, with those in the trial having, on average, more educated parents and higher maternal employment. Trial children were less likely to have barefoot exposure and more likely to use insecticide-treated bed nets. There were no significant differences in numbers of reported illness events over the last year. Conclusions: The trial had not enrolled all eligible participants, and those enrolled were of higher socioeconomic status, and had lower risk of exposure to the parasitic infections targeted by the trial interventions. It is possible the trial may have underestimated the absolute effects of anthelminthic treatment during pregnancy and early childhood, although the fact that there were no differences in reported incidence of common infectious diseases (one of the primary outcomes of EMaBS) between the two groups provides reassurance. Concurrent community surveys may be an effective way to test the external validity of trials. EMaBS Trial registration: ISRCTN32849447, registered 22 July 2005
Association between malaria exposure and Kaposi’s sarcoma-associated herpes virus seropositivity in Uganda
(John Wiley & Sons Ltd., 2015) Nalwoga, Angela; Cose, Stephen; Wakeham, Katie; Miley, Wendell; Ndibazza, Juliet; Drakeley, Christopher; Elliott, Alison M; Whitby, Denise; Newton, Robert
Objective: Unlike other herpes viruses, Kaposi’s sarcoma-associated herpes virus (KSHV) is not ubiquitous worldwide and is most prevalent in sub-Saharan Africa. The reasons for this are unclear. As part of a wider investigation of factors that facilitate transmission in Uganda, a high prevalence country, we examined the association between antimalaria antibodies and seropositivity against KSHV. methods Antibodies against P. falciparum merozoite surface protein (PfMSP)-1, P. falciparum apical membrane antigen (PfAMA)-1 and KSHV antigens (ORF73 and K8.1) were measured in samples from 1164 mothers and 1227 children. results Kaposi’s sarcoma-associated herpes virus seroprevalence was 69% among mothers and 15% children. Among mothers, KSHV seroprevalence increased with malaria antibody titres: from 60% to 82% and from 54% to 77%, comparing those with the lowest and highest titres for PfMSP-1 and PfAMA-1, respectively (P < 0.0001). Among children, only antibodies to PfAMA-1 were significantly associated with KSHV seropositivity, (P < 0.0001). In both mothers and children, anti-ORF73 antibodies were more strongly associated with malaria antibodies than anti-K8.1 antibodies. Conclusion: The association between malaria exposure and KSHV seropositivity suggests that malaria is a cofactor for KSHV infection or reactivation.
Associations Between Maternal Helminth and Malaria Infections in Pregnancy and Clinical Malaria in the Offspring: A Birth Cohort in Entebbe, Uganda
(Oxford University Press on behalf of the Infectious Diseases Society of America, 2013) Ndibazza, Juliet; Webb, Emily L; Lule, Swaib; Mpairwe, Harriet; Akello, Miriam; Oduru, Gloria; Kizza, Moses; Akurut, Helen; Muhangi, Lawrence; Magnussen, Pascal; Vennervald, Birgitte J.; Elliott, Alison M
Helminth and malaria coinfections are common in the tropics. We investigated the hypothesis that prenatal exposure to these parasites might influence susceptibility to malaria in childhood. Methods. In a birth cohort of 2345 mother–child pairs in Uganda, maternal helminth and malaria infection status was determined during pregnancy, and childhood malaria episodes were recorded from birth to age 5 years. We examined associations between maternal infections and malaria in the offspring. Results. Common maternal infections were hookworm (45%), Mansonella perstans (21%), Schistosoma mansoni (18%), and Plasmodium falciparum (11%). At age 5 years, 69% of the children were still under follow-up. The incidence of malaria was 34 episodes per 100 child-years, and the mean prevalence of asymptomatic malaria at annual visits was 5.4%. Maternal hookworm and M. perstans infections were associated with an increased rate of childhood clinical malaria (adjusted hazard ratio [aHR], 1.24, 95% confidence interval [CI], 1.10–1.41; aHR, 1.20, 95% CI, 1.05–1.38, respectively). S. mansoni infection had no consistent association with childhood malaria. Conclusions. This is the first report of an association between helminth infections in pregnancy and malaria in the offspring and indicates that helminth infections in pregnancy may increase the burden of childhood malaria morbidity.
A Description of Congenital Anomalies Among Infants in Entebbe, Uganda
(Wiley-Liss, Inc., 2011) Ndibazza, Juliet; Lule, Swaib; Nampijja, Margaret; Mpairwe, Harriet; Oduru, Gloria; Kiggundu, Molly; Akello, Miriam; Muhangi, Lawrence; Elliott, Alison M
Background: Data on congenital anomalies from developing countries of the sub-Saharan region are scarce. However, it is important to have comprehensive and reliable data on the description and prevalence of congenital anomalies to allow surveillance and the implementation of appropriate public health strategies for prevention and management. In this study, we describe the profile of congenital anomalies seen in a birth cohort in Entebbe, Uganda. Methods: Congenital anomalies were defined as any structural defect present at birth. Pregnant women were recruited to the cohort between 2003 and 2005. Defects present at birth were recorded by the midwife at delivery and by physicians at the routine six-week postnatal visit and at illness-related visits until 1 year of life. The anomalies were classified by organ system according to the 10th version of the World Health Organization International Classification of Diseases (ICD-10). Results: There were 180 infants with a congenital anomaly among 2365 births. The most commonly affected systems were the musculoskeletal (42.7 per 1000 births) and skin (16.1 per 1000 births). The prevalence of major anomalies was 20.3 per 1000 births; 1.7 per 1000 births for cardiac anomalies and 1.3 per 1000 births for neural system anomalies. Forty (22%) of the congenital anomalies were identified at birth, 131 (73%) at the 6-week postnatal visit, and nine (5%) at illness-related visits. CONCLUSION: Congenital anomalies are common in developing countries. Establishment of comprehensive databases for surveillance would be helpful for surveillance of effects of new exposures, for prevention, management, and health care planning. Birth Defects Research (Part A) 91:857–861, 2011. _ 2011 Wiley-Liss, Inc.
The impact of helminths on the response to immunization and on the incidence of infection and disease in childhood in Uganda: design of a randomized, double-blind, placebo-controlled, factorial trial of deworming interventions delivered in pregnancy and early childhood [ISRCTN32849447]
(Society for Clinical Trials, 2007) Elliott, Alison M; Kizza, Moses; Quigley, Maria A; Ndibazza, Juliet; Nampijja, Margaret; Muhangi, Lawrence; Morison, Linda; Namujju, Proscovia B; Muwanga, Moses; Kabatereine, Narcis; Whitworth, James AG
Helminths have profound effects on the immune response, allowing long-term survival of parasites with minimal damage to the host. Some of these effects “spill-over”, altering responses to non-helminth antigens or allergens. It is suggested that this may lead to impaired responses to immunizations and infections, while conferring benefits against inflammatory responses in allergic and autoimmune disease. These effects might develop in utero, through exposure to maternal helminth infections, or through direct exposure in later life. Purpose To determine the effects of helminths and their treatment in pregnancy and in young children on immunological and disease outcomes in childhood. Methods The trial has three randomized, double-blind, placebo-controlled interventions at two times, in two people: a pregnant woman and her child. Pregnant women are randomized to albendazole or placebo and praziquantel or placebo. At age 15 months their children are randomized to three-monthly albendazole or placebo, to continue to age five years. The proposed designation for this sequence of interventions is a 2 _ 2(_2) factorial design. Children are immunized with BCG and against polio, Diphtheria, tetanus, Pertussis, Haemophilus, hepatitis B and measles. Primary immunological outcomes are responses to BCG antigens and tetanus toxoid in whole blood cytokine assays and antibody assays at one, three and five years of age. Primary disease outcomes are incidence of malaria, pneumonia, diarrhoea, tuberculosis, measles, vertical HIV transmission, and atopic disease episodes, measured at clinic visits and twice-monthly home visits. Effects on anaemia, growth and intellectual development are also assessed. Conclusion This trial, with a novel design comprising related interventions in pregnant women and their offspring, is the first to examine effects of helminths and their treatment in pregnancy and early childhood on immunological, infectious disease and allergic disease outcomes. The results will enhance understanding of both detrimental and beneficial effects of helminth infection and inform policy.
Maternal hookworm modifies risk factors for childhood eczema: results from a birth cohort in Uganda
(Pediatric Allergy and Immunology, 2014) Mpairwe, Harriet; Ndibazza, Juliet; Webb, Emily L; Nampijja, Margaret; Muhangi, Lawrence; Apule, Barbara; Lule, Swaib; Akurut, Helen; Kizito, Dennison; Kakande, Mohammed; Jones, Frances M; Fitzsimmons, Colin M.; Muwanga, Moses; Rodrigues, Laura C.; Dunne, David W; Elliott, Alison M
Background: Worms may protect against allergy. Early-life worm exposure may be critical, but this has not been fully investigated. Objectives: To investigate whether worms in pregnancy and in early childhood are associated with childhood eczema incidence. Methods: The Entebbe Mother and Baby Study, an anthelminthic treatment trial, enrolled pregnant women between 2003 and 2005 in Uganda. Mothers were investigated for worms during pregnancy and children annually. Eczema was doctor-diagnosed from birth to age five years. A planned observational analysis was conducted within the trial cohort to investigate associations between worms and eczema. Results: Data for 2345 live-born children were analysed. Hookworm was the most prevalent maternal worm (45%). Childhood worms were less prevalent. Eczema incidence was 4.68/100 person-years. Maternal hookworm was associated with reduced eczema incidence [adjusted hazard ratio (95% confidence interval), p-value: 0.71(0.51–0.99), 0.04] and modified effects of known risk factors for eczema: Dermatophagoides-specific IgE in children was positively associated with eczema incidence if the mother had no hookworm [2.72(1.11–6.63), 0.03], but not if the mother had hookworm [0.41(0.10–1.69), 0.22], interaction p-value = 0.03. Similar interactions were seen for maternal history of eczema {[2.87(1.31–6.27, 0.008) vs. [0.73(0.23–2.30), 0.60], interaction p-value = 0.05}, female gender {[1.82(1.22–2.73), 0.004 vs. [0.96 (0.60–1.53), 0.87], interaction p-value = 0.04} and allergen-specific IgE. Childhood Trichuris trichiura and hookworm were inversely associated with eczema. Conclusions: Maternal hookworm modifies effects of known risk factors for eczema. Mechanisms by which early-life worm exposures influence allergy need investigation. Worms or worm products, and intervention during pregnancy have potential for primary prevention of allergy.
Parasite infection is associated with Kaposi’s sarcoma associated herpesvirus (KSHV) in Ugandan women
(BioMed Central, 2011) Wakeham, Katie; Webb, Emily L; Sebina, Ismail; Muhangi, Lawrence; Miley, Wendell; Johnson, W Thomas; Ndibazza, Juliet; Elliott, Alison M; Whitby, Denise; Newton, Robert
Background: Immune modulation by parasites may influence susceptibility to bacteria and viruses. We examined the association between current parasite infections, HIV and syphilis (measured in blood or stool samples using standard methods) and antibodies against Kaposi’s sarcoma herpesvirus (KSHV), measured by ELISA, in 1915 stored plasma samples from pregnant women in Entebbe, Uganda. Results: Seroprevalence of KSHV was higher in women with malaria parasitaemia (73% vs 60% p = 0.01), hookworm (67% vs 56% p = 0.001) and Mansonella perstans (69% vs 59% p = 0.05); seroprevalence increased with increasing intensity of hookworm infection (p < 0.001[trend]). No associations were found for HIV, five other parasites or active syphilis. These effects were not explained by socioeconomic status or education. Conclusions: Specific parasite infections are associated with presence of antibodies against KSHV, perhaps mediated via their effect on immune function.
Risk Factors for Seropositivity to Kaposi Sarcoma–Associated Herpesvirus Among Children in Uganda
(Lippincott Williams & Wilkins, 2013) Wakeham, Katie; Webb, Emily L.; Sebina, Ismail; Nalwoga, Angela; Muhangi, Lawrence; Miley, Wendell; Johnston, Thomas; Ndibazza, Juliet; Whitby, Denise; Newton, Robert; Elliott, Alison M
Background: Determinants of Kaposi sarcoma–associated herpesvirus (KSHV) seropositivity among children living in sub-Saharan African populations where infection is endemic are not well understood. Local environmental factors, including other infectious agents, may be key. Methods: Within the context of a well-characterized birth cohort, we examined associations between various factors and antibodies against KSHV, measured in stored plasma samples from 1823 mother–child pairs in Entebbe, Uganda. Results: Seroprevalence increased with increasing age of the child (P = 0.0003) and was higher among those with KSHV seropositive mothers than in those without (12% vs 9%; odds ratio: 1.4, 95% confidence interval: 1.1 to 2.0). It was also higher among children with HIV infection (29% vs 10%; odds ratio: 3.1, 95% confidence interval: 1.2 to 8.3) or malaria parasitemia (30% vs 10%; odds ratio: 4.1, 95% confidence interval: 2.4 to 7.0) than in children without. These associations were not explained by socioeconomic status. Conclusions: The finding that KSHV serostatus is associated with malaria parasitemia in children is novel. In a country endemic for KSHV, malaria may be a cofactor for KSHV infection or reactivation among children.
Treatment with anthelminthics during pregnancy: what gains and what risks for the mother and child?
(Cambridge University Press, 2011) Elliott, Alison M; Ndibazza, Juliet; Mpairwe, Harriet; Muhangi, Lawrence; Webb, Emily L; Kizito, Dennison; Mawa, Patrice A; Tweyongyere, Robert; Muwanga, Moses
In 1994 and 2002, respectively, theWorld Health Organisation proposed that treatment for hookworm and schistosomiasis could be provided during pregnancy. It was hoped that this might have benefits for maternal anaemia, fetal growth and perinatal mortality; a beneficial effect on the infant response to immunisation was also hypothesised. Three trials have now been conducted. Two have examined the effects of benzimidazoles; one (the Entebbe Mother and Baby Study) the effects of albendazole and praziquantel. All three were conducted in settings of high prevalence but low intensity helminth infection. Results suggest that, in such settings and given adequate provision of haematinics, the benefit of routine anthelminthics during pregnancy for maternal anaemia may be small; none of the other expected benefits has yet been demonstrated. The Entebbe Mother and Baby Study found a significant adverse effect of albendazole on the incidence of infantile eczema in the whole study population, and of praziquantel on the incidence of eczema among infants of mothers with Schistosoma mansoni. Further studies are required in settings that differ in helminth species and infection intensities. Further research is required to determine whether increased rates of infantile eczema translate to long-term susceptibility to allergy, and to explore the underlying mechanisms of these effects. The risks and benefits of routine anthelminthic treatment in antenatal clinics may need to be reconsidered.