Infants spend the majority of their time in the home and therefore this seems likely to be the location where EV71 infection is acquired, possibly from other members of the household
Infants spend the majority of their time in the home and therefore this seems likely to be the location where EV71 infection is acquired, possibly from other members of the household. mouth ulcers and vesicular rash on the palms of the hands and the soles of the feet. Children may have reduced appetite due to painful vesicles in the mouth cavity. Children less than 5 years of age account for the majority of hospitalized HFMD cases [1], [2], [3], [4] and although it is usually mild and self-limiting, severe organ impairment can occur which occasionally leads to death [4], [5]. Large epidemics of HFMD in the World Health Organization’s Western Pacific Region have recently been described [5] and have been associated UPF-648 with severe and fatal outcomes [6], [7], [8]. HFMD is caused by members of the Enterovirus genus, mainly, coxsackievirus A16 or enterovirus 71 [9]. In addition, sporadic cases with coxsackievirus types A4CA7, A9, A10, B1CB3, and B5 have been reported [2], [9]. Human enterovirus 71 (EV71) has been more frequently associated with severe forms of HFMD such as aseptic meningitis, polio-like paralysis and/or encephalitis [5]. The basis for the relatively greater virulence of EV71 is unclear but might be associated with viral genetics [10]. There are no vaccines or specific therapies to prevent or treat severe HFMD. HFMD has emerging as a public health problem in the south of Viet Nam and is associated primarily with Coxsackievirus A16 or EV71 infection. A previous study by Tu et al. outlined the age-related epidemiology of hospitalized EV71-associated HFMD in the largest children’s hospital in Ho Chi Minh City [2]. To more fully explore the scale of EV71 virus transmission in the healthy infants and children in Ho Chi Minh City, we undertook a prospective seroincidence survey of a cohort of newborn infants followed from birth to their 2nd birthday. In parallel, we conducted a cross-sectional sero-prevalence study of EV71 neutralizing antibodies in Vietnamese children and adults. Materials and Methods The study protocol were approved by the Scientific and Ethical committees at Hung Vuong Obstetric Hospital, Hospital for Tropical Diseases and UPF-648 the Oxford University Tropical Research Ethical committee. Written informed consent was obtained from the mother in the birth cohort study and the accompanying parent/guardian in the community dengue study. Collection of cord and infant plasma samples The decay of maternally derived anti-EV71 neutralizing antibodies and the seroincidence of EV71 infection in the first year of life was determined using serial plasma samples collected from 200 infants born at Hung Vuong Obstetric Hospital, Ho Chi Minh City, between September 2006CSeptember 2007. All 200 infants were participants in a prospective birth cohort, the methods for which have been described previously [11]. From each infant, cord blood was collected at the time of birth and plasma samples were collected SMOC2 at four follow-up visits (3, 6, 9 and 12 months). Collection of plasma samples in a cross-sectional survey of children and young adults To determine the age-related seroprevalence of EV71 neutralizing antibodies in relatively older children we collected plasma from 263 young children at 12-, 18- and 24- months of age, and 120 children aged from 5C15 years. The plasma samples from infants aged 12 or 24 months of age were collected in the same birth cohort study described previously but who were not represented in the 200 infants in whom seroincidence rates were determined. The plasma samples from children aged 5C15 years were collected as part of a community-based study of dengue at District 8 Hospital, Ho Chi Minh City between September 2005CJanuary 2009. Participants were children with suspected dengue. For the purposes of determining EV71 seroprevalence levels in this age group, we selected plasma samples from 120 children between 5 and 15 yrs of age from whom blood samples had been collected 14 days after study enrolment and who had no serological or virological evidence of dengue infection. The diagnosis in these not dengue cases was not determined, but were presumed viral infections. There was no clinical evidence UPF-648 to suggest these were HFMD cases. Cord blood were used to provide the results in young adults. EV71 virus neutralization assay We defined neutralizing antibody levels in plasma to an EV71 virus (EV71/7423/MS87) isolated in Mississippi USA in 1987. In brief, the experiments were run in 96-well plates. Vero cells were prepared at 104 cells/well and left overnight. Diluted plasma was incubated with.