Low seroprotection against diphtheria and tetanus in Lao adolescents.

Objectives: There is currently no booster diphtheria or tetanus vaccine for Lao children before adolescence, despite international recommendations. We investigated seroprotection against diphtheria and tetanus among Lao adolescents.

Methods: Seven hundred seventy-nine serum samples were tested for anti-diphtheria and anti-tetanus antibodies.

Analyses of blood donor samples from eight provinces in Lao PDR suggest considerable variation concerning HBV exposure and carriage.

Introduction: Hepatitis B is endemic in Lao PDR and about 9% of the adult population is chronically infected. In this study, we investigated regional, occupational, age and sex-related differences in hepatitis B epidemiology in Lao blood donors.

Methods: 5017 voluntary blood donors from 8 different provinces were tested for hepatitis B markers by ELISA.

Waning of Maternal Antibodies against Measles Suggests a Large Window of Susceptibility in Infants in Lao People's Democratic Republic.

Introduction: Measles is an endemic but largely neglected disease in Lao People's Democratic Republic. New-borns are protected by maternal antibodies, but antibody waning before measles vaccination at 9 months of age leaves infants susceptible to infection. In this study, the susceptibility window of infants was determined to generate scientific evidence to assess the national measles immunization strategy.

Timeliness of immunisation with the pentavalent vaccine at different levels of the health care system in the Lao People's Democratic Republic: A cross-sectional study.

Background: The timely administration of vaccines is considered to be important for both individual and herd immunity. In this study, we investigated the timeliness of the diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (pentavalent) vaccine, scheduled at 6, 10 and 14 weeks of age in the Lao People's Democratic Republic. We also investigated factors associated with delayed immunization.

Hepatitis A Virus in Lao People's Democratic Republic: Seroprevalence and Risk Factors.

Despite several recent reports of outbreaks of hepatitis A, little is known about the disease burden in Lao People's Democratic Republic (PDR). We conducted a cross-sectional age-stratified seroprevalence study of anti-hepatitis A virus (HAV) IgG and risk factors in a rural province (Xiengkhouang) and Vientiane capital in Lao PDR. Overall, 62% of participants were anti-HAV positive in Xiengkhouang Province compared with 45.

Pertussis in Lao PDR: Seroprevalence and disease.

Objectives: Pertussis is a debilitating vaccine-preventable infection. The aim of this study was to determine susceptibility and exposure to pertussis in Lao PDR in different age groups and subpopulations.

Methods: A total 3072 serum samples were obtained from different cohorts: children with documented vaccination, pre-schoolers, schoolchildren, blood donors, healthcare workers (HCWs), and pregnant women and paired cord blood.

Lasting benefit of infant hepatitis B vaccination in adolescents in the Lao People's Democratic Republic.

Objectives: Hepatitis B is endemic in Lao PDR with 8-10% of the adult population being chronically infected. We investigated the impact of hepatitis B vaccination on infection in adolescents born shortly before and after the introduction of the vaccine in 2001.

Methods: 779 students from Vientiane Capital and Bolikhamxay province were tested for HBV markers by ELISA.

Cross-species transmission of poultry pathogens in backyard farms: ducks as carriers of chicken viruses.

In backyard farms of Lao People's Democratic Republic, mixed-species rearing of poultry is a breeding-ground for cross-species transmission. Here, the epidemiology of viruses circulating among backyard poultry in Vientiane Province was assessed to guide future control strategies. Oral/tracheal and cloacal swabs, collected from 605 poultry (308 ducks, 297 chickens) between 2011 and 2015, were screened by PCR for Newcastle disease virus (NDV), coronavirus (CoV) and chicken anaemia virus (CAV).

Varicella zoster and fever rash surveillance in Lao People's Democratic Republic.

Background: In Lao PDR, the epidemiology of varicella infection is uncertain, since it is not a notifiable disease and VZV outbreaks are rarely reported as fever/rash (F/R) diseases.

Methods: We estimated the seroprevalence of VZV (IgG ELISA) in different age cohorts (9 months to 46 years; N = 3139) and investigated VZV and 6 other viruses in patients during F/R outbreaks and in an ad hoc sentinel site in the context of the national reporting system (IgM ELISA, PCR).

Results: At least 80% of the sampled population had evidence of VZV infection before the age of 15.

Seroprotection at Different Levels of the Healthcare System After Routine Vaccination With Diphtheria-Tetanus-Pertussis whole cell-Hepatitis B-Haemophilus influenzae Type B in Lao People's Democratic Republic.

Background: The Lao People's Democratic Republic continues to sustain a considerable burden of vaccine-preventable diseases because of incomplete vaccine coverage and weak vaccine responses. We have assessed seroconversion after routine vaccination with the pentavalent vaccine to capture weaknesses of vaccine management at the different levels of the healthcare system.

Methods: A total of 1151 children (aged 8-28 months) with 3 documented doses of the pentavalent vaccine delivered at central hospitals in Vientiane and the provincial hospital, 3 district hospitals, and 10 health centers in Bolikhamxay province were enrolled.

High circulation of Hepatitis E virus in pigs and professionals exposed to pigs in Laos.

Epidemiological characteristics of hepatitis E Virus (HEV) differ due to the vast spatial heterogeneity in sanitation status, dietary habits and extent of exposure to animals. Although HEV infections are mostly asymptomatic, prognosis is poor for patients with compromised immune systems or pre-existing liver disease and during pregnancy. In developing countries, low hygienic standards and close human-animal interactions at farms and slaughterhouses likely favour zoonotic transmission of the virus.

Immunity levels to poliovirus in Lao children and adults before the vaccine-derived poliovirus outbreak: A retrospective study.

In 2015, several provinces in Lao People's Democratic Republic (Lao PDR) experienced a vaccine-derived poliovirus outbreak. This survey was conducted (i) to evaluate the vaccination coverage in different settings and cohorts using the seroprevalence of anti-poliovirus (PV) antibodies as a surrogate measure, and (ii) to explore the usefulness of an ELISA in a country with limited resources and a specific epidemiological setting. IgG antibodies were assessed by ELISA in Lao children (n = 1216) and adults (n = 1228), including blood donors and health care workers.

Diphtheria in Lao PDR: Insufficient Coverage or Ineffective Vaccine?

Background: During late 2012 and early 2013 several outbreaks of diphtheria were notified in the North of the Lao People's Democratic Republic. The aim of this study was to determine whether the re-emergence of this vaccine-preventable disease was due to insufficient vaccination coverage or reduction of vaccine effectiveness within the affected regions.

Methods: A serosurvey was conducted in the Huaphan Province on a cluster sampling of 132 children aged 12-59 months.

Urinary podocalyxin, the novel biomarker for detecting early renal change in obesity.

Background: The prevalence of obesity is increasing during the past decade along with obesity-related glomerulopathy (ORG), glomeruli injury due to the obesity. The major pathogenesis of ORG is the shedding of podocytes from the glomerular cell barrier into urine. Podocalyxin (PCX), a main surface antigen of podocyte, correlates well with glomerulosclerosis progression and glomerular injury severity, and might be a potential biomarker for early renal alteration in obesity.

Serosurveillance of vaccine preventable diseases and hepatitis C in healthcare workers from Lao PDR.

Background And Aims: Healthcare workers (HCW) have an increased risk of exposure to infectious diseases and are a potential source of infections for their patients. The Lao People's Democratic Republic (Lao PDR) has no national policy regarding HCW vaccinations and routine vaccination coverage is low within the general population. This cross-sectional serostudy determines the level of exposure and risk of infection in Lao HCW against 6 vaccine preventable diseases and hepatitis C.

Hepatitis B virus in the Lao People's Democratic Republic: a cross sectional serosurvey in different cohorts.

Background: Despite hepatitis B vaccination at birth and at 6, 10 and 14 weeks of age, hepatitis B virus (HBV) infection continues to be endemic in the Lao People's Democratic Republic (PDR). We carried out a cross-sectional serological study in infants, pre-school children, school pupils and pregnant women to determine their burden of disease, risk of infection and vaccination status.

Methods: A total of 2471 participants between 9 months and 46 years old were recruited from urban (Vientiane Capital, Luang Prabang), semi-urban (Boulhikhamxai and Savannakhet) and remote rural areas (Huaphan).

Immunoglobulin values in healthy Thai children aged ≤ 24 months determined by nephelometry.

Background: Variation of normal immunoglobulin (Ig) levels between different genetic and environment factors has been studied. Although antibody deficiency diseases can start from infancy, data of Ig reference levels in children aged ≤24 months are still limited, especially in Asian children.

Purpose: The aim of this study was to determine serum IgG, IgA, IgM, and IgG subclasses in healthy Thai children from the newborn period to age 24 months.

Nephelometry determined serum immunoglobulin isotypes in healthy Thai children aged 2-15 years.

Knowledge of what constitute normal serum immunoglobulin (Ig) concentrations are important for the diagnosis of immunologic disorders. Data on normal Ig evaluated by nephelometry are limited in healthy Asian children, none being available for Thai children. One hundred and forty-eight healthy Thai children aged 2-15 years were tested for serum immunoglobulins G, A, M, G1, G2, G3, and G4 (Ig G, A, M, G1, G2, G3, and G4) by nephelometry.

Novel low-cost assay for the monitoring of CD4 counts in HIV-infected individuals.

Several CD4 lymphocyte enumeration methods have been developed to be used as alternatives to conventional flow cytometry. However, no consensus has been reached on which technique should be widely adopted. We introduce here a novel nonflow cytometric method, called CD4 Select, for enumeration of CD4 lymphocytes.

A simple manual rosetting method for absolute CD4+ lymphocyte counting in resource-limited countries.

A CD4 monoclonal antibody which reacts with CD4+ lymphocytes but does not react significantly with monocytes was generated and used to develop a simple method for CD4 count. In a comparison with standard flow cytometry, high correlation was obtained. The developed method can be an alternative to flow cytometry for resource-limited countries.