Spread of genetically similar noroviruses in Bangkok, Thailand, through symptomatic and asymptomatic individuals.

Norovirus infection is a major cause of acute gastroenteritis, although some infected individuals are asymptomatic. GII.4 is the predominant genotype worldwide and, since 2000, has been the most prevalent in patients in Thailand with acute gastroenteritis. We screened stool samples for norovirus in 786 patients with acute gastroenteritis who were admitted to a hospital in Bangkok from 2017 to early 2019 and detected it in 136 specimens (17.3%). Eight and 124 specimens were positive for the GI and GII genogroups, respectively, and the remaining 4 specimens were double-positive. Nine genotypes (GI.3, GI.5, GII.2, GII.3, GII.4, GII.6, GII.8, GII.13, and GII.17) were identified from 140 strains, and 72 strains (51.4%) were GII.4. We had previously conducted a one-year survey of norovirus infection in residents of a community in Bangkok from May 2018 to April 2019 and found that a substantial portion of the residents were infected asymptomatically. The 9 genotypes identified in the patients were also commonly identified in the community residents. To investigate the relationship between noroviruses identified in the acute gastroenteritis patients and those identified in the community residents, phylogenetic tree analysis was conducted. Of the 9 genotypes, 8 showed similarities in both their genomic sequences and their deduced amino acid sequences. In addition, strain replacement of GI.3 was observed in both the patients and the community residents within the overlapping period. These results suggested that norovirus spreads efficiently to the community by simultaneously causing symptomatic and asymptomatic infections.

Accuracy and Cross-Reactivity of Rapid Diagnostic Tests for Norovirus and Rotavirus in a Real Clinical Setting.

BACKGROUND: Rapid diagnostic test (RDT) of norovirus and rotavirus is commonly used for outbreak screening and patient management. Varying accuracy of the test and cross-reactivity has been reported and could affect the outcome of management. The primary purpose of this study is to provide the accuracy of norovirus and rotavirus rapid diagnostic tests and to analyze the cross-reactivity of both tests. MATERIALS AND METHODS: Stool samples collected from every acute diarrhea patient aged <15 years old who was admitted at Bhumibol Adulyadej Hospital, Bangkok, Thailand, from November 2014 to September 2016 underwent the following test: QuickNaviTM - Norovirus2 for norovirus, VIKIA® Rota-Adeno for rotavirus, and aerobic bacterial culture. Real-time reverse transcription polymerase chain reaction was used as a gold standard for virus detection. False-positive results determined cross-reactivity. RESULTS: From 358 stool specimens, the sensitivity of RDTs for norovirus and rotavirus was 27.5% and 44.8%, respectively. The specificity of RDTs for norovirus and rotavirus was 97.7% and 91.6%, respectively. False positive results of RDT for norovirus occurred in 6 samples (1.7%) and 22 samples (6.1%) in RDT for rotavirus. Rotavirus RDT was found to have cross-reactivity with 11 norovirus infection and 3 bacterial infected stools. CONCLUSION: We found that the RDTs for both rotavirus and norovirus have high specificity but low sensitivity. Cross-reactivity was observed in positive rotavirus RDT with half of it being norovirus.

Incidence and risk factors of loss to follow-up among HIV-infected children in an antiretroviral treatment program.

INTRODUCTION: The success of antiretroviral treatment (ART) programs can be compromised by high rates of patient loss to follow-up (LTFU). We assessed the incidence and risk factors of LTFU in a large cohort of HIV-infected children receiving ART in Thailand. METHODS: All children participating in a multicenter cohort (NCT00433030) between 1999 and 2014 were included. The date of LTFU was 9 months after the last contact date. ART interruption was defined as ART discontinuation for more than 7 days followed by resumption of treatment. Baseline and time-dependent risk factors associated with LTFU were identified using Fine and Gray competing risk regression models with death or referral to another hospital as competing events. RESULTS: Of 873 children who were followed during a median of 8.6 years (interquartile range 4.5-10.6), 196 were LTFU, 73 died, and 195 referred. The cumulative incidence of LTFU was 2.9% at 1 year, 7.3% at 5 years and 22.2% at 10 years. Children aged 13 years and more had a 3-fold higher risk (95% confidence interval 2.06-4.78) of LTFU than those younger. Children who had interrupted ART within the previous year had a 2.5-fold higher risk (1.12-5.91) than those who had not. The risk of LTFU was lower in children stunted (height-for-age Z-scores <-2 SD) (0.42-0.96) or underweight (weight-for-age Z-scores <-2 SD) (0.24-0.97). CONCLUSION: Adolescence, ART interruption and absence of growth deficit were associated with LTFU. These may be warnings that should draw clinicians' attention and possibly trigger specific interventions. Children with no significant growth retardation may also be at risk of LTFU.

Role of efavirenz plasma concentrations on long-term HIV suppression and immune restoration in HIV-infected children.

BACKGROUND: To access the long term relationship between efavirenz plasma concentrations and evolution of HIV RNA loads and CD4 cell counts in children. METHODS: Retrospective analysis of data from HIV-infected children on first line efavirenz-containing regimen. A population pharmacokinetic-pharmacodynamic (PK-PD) model was developed to describe the evolution of HIV RNA load and CD4 cell count (efficacy outcomes) in relation to efavirenz plasma concentration. Individual CYP2B6 516 G>T genotype data were not available for this analysis. A score (ISEFV) quantifying the effect of efavirenz concentrations on the long-term HIV replication was calculated from efavirenz concentrations and PD parameters and, a value of ISEFV below which HIV replication is likely not suppressed was determined. Cox proportional hazards regression models were used to assess the association of the risk of viral replication with ISEFV, and with efavirenz mid-dose concentration(C12). RESULTS: At treatment initiation, median (interquartile range, IQR) age was 8 years (5 to 10), body weight 17 kg (14 to 23), HIV RNA load 5.1 log10 copies/mL (4.6 to 5.4), and CD4 cell count 71 cells/mm3. A model of PK-PD viral dynamics assuming that efavirenz decreases the rate of infected host cells adequately described the relationship of interest. After adjusting for age, baseline HIV RNA load and CD4 cell counts an ISEFV <85% was significantly associated with a higher risk of viral replication (p-value <0.001) while no significant association was observed with C12 <1.0 mg/L. CONCLUSION: The ISEFV score was a good predictor of viral replication in children on efavirenz-based treatment.

The dynamics of norovirus genotypes and genetic analysis of a novel recombinant GII.P12-GII.3 among infants and children in Bangkok, Thailand between 2014 and 2016.

Norovirus (NoV) is the leading cause of viral acute gastroenteritis among all age groups in the world. We performed a molecular epidemiological study of the NoVs prevalent in Bangkok between November 2014 and July 2016 to investigate the emergence of new NoV variants in Thailand. A total of 332 stool specimens were collected from hospitalized pediatric patients with acute gastroenteritis in Bangkok, Thailand. NoVs were detected by real-time PCR. The genome of the N-terminal/shell domain was amplified, the nucleotide sequence was determined, and phylogenetic analyses were performed. GII NoV was detected in 58 (17.5%) of the 332 specimens. GII.17, a genotype strain prevalent from 2014 to mid-2015, was hardly detected and replaced by the GII.3 genotype strain. Entire genome sequencing followed by phylogenetic analysis of the GII.3 genotype strains indicated that they are new recombinant viruses, because the genome encoding ORF1 is derived from a GII.12 genotype strain, whereas that encoding ORF2-3 is from a GII.3 genotype strain. The putative recombination breakpoints with the highest statistical significance were located around the border of 3Dpol and ORF2. The change in the prevalent strain of NoV seems to be linked to the emergence of new forms of recombinant viruses. These findings suggested that the swapping of the structural and non-structural proteins of NoV is a common mechanism by which new epidemic variants are generated in nature.

Brief Report: AIDS-Defining Events and Deaths in HIV-Infected Children and Adolescents on Antiretrovirals: A 14-Year Study in Thailand.

BACKGROUND: Data are scarce on the long-term clinical outcomes of perinatally HIV-infected children and adolescents receiving antiretroviral therapy (ART) in low/middle-income countries. We assessed the incidence of mortality before (early) and after (late) 6 months of ART and of the composite outcome of new/recurrent AIDS-defining event or death >6 months after ART start (late AIDS/death) and their associated factors. METHODS: Study population was perinatally HIV-infected children (≤18 years) initiating ART within the Program for HIV Prevention and Treatment observational cohort (NCT00433030). Factors associated with late AIDS/death were assessed using competing risk regression models accounting for lost to-follow-up and included baseline and time-updated variables. RESULTS: Among 619 children, "early" mortality incidence was 99 deaths per 1000 person-years of follow-up [95% confidence interval (CI): 69 to 142] and "late" mortality 6 per 1000 person-years of follow-up (95% CI: 4 to 9). Of the 553 children alive >6 months after ART initiation, median age at ART initiation was 6.4 years, CD4% 8.2%, and HIV-RNA load 5.1 log10 copies/mL. Thirty-eight (7%) children developed late AIDS/death after median time of 3.3 years: 24 died and 24 experienced new/recurrent AIDS-defining events (10 subsequently died). Factors independently associated with late AIDS/death were current age ≥13 years (adjusted subdistribution hazard ratio 4.9; 95% CI: 2.4 to 10.1), HIV-RNA load always ≥400 copies/mL (12.3; 95% CI: 4.0 to 37.6), BMI-z-score always <-2 SD (13.7; 95% CI: 3.4 to 55.7), and hemoglobin <8 g/dL at least once (4.6; 95% CI: 2.0 to 10.5). CONCLUSIONS: After the initial 6 months of ART, being an adolescent, persistent viremia, poor nutritional status, and severe anemia were associated with poor clinical outcomes. This supports the need for novel interventions that target children, particularly adolescents with poor growth and uncontrolled viremia.

Cost-effectiveness of early infant HIV diagnosis of HIV-exposed infants and immediate antiretroviral therapy in HIV-infected children under 24 months in Thailand.

BACKGROUND: HIV-infected infants have high risk of death in the first two years of life if untreated. WHO guidelines recommend early infant HIV diagnosis (EID) of all HIV-exposed infants and immediate antiretroviral therapy (ART) in HIV-infected children under 24-months. We assessed the cost-effectiveness of this strategy in HIV-exposed non-breastfed children in Thailand. METHODS: A decision analytic model of HIV diagnosis and disease progression compared: EID using DNA PCR with immediate ART (Early-Early); or EID with deferred ART based on immune/clinical criteria (Early-Late); vs. clinical/serology based diagnosis and deferred ART (Reference). The model was populated with survival and cost data from a Thai observational cohort and the literature. Incremental cost-effectiveness ratio per life-year gained (LYG) was compared against the Reference strategy. Costs and outcomes were discounted at 3%. RESULTS: Mean discounted life expectancy of HIV-infected children increased from 13.3 years in the Reference strategy to 14.3 in the Early-Late and 17.8 years in Early-Early strategies. The mean discounted lifetime cost was $17,335, $22,583 and $29,108, respectively. The cost-effectiveness ratio of Early-Late and Early-Early strategies was $5,149 and $2,615 per LYG, respectively as compared to the Reference strategy. The Early-Early strategy was most cost-effective at approximately half the domestic product per capita per LYG ($4,420 in Thailand 2011). The results were robust in deterministic and probabilistic sensitivity analyses including varying perinatal transmission rates. CONCLUSION: In Thailand, EID and immediate ART would lead to major survival benefits and is cost- effective. These findings strongly support the adoption of WHO recommendations as routine care.

Invasive pneumococcal infection in neonates: 3 case reports.

Streptococcus pneumoniae is a rarely recognized cause of neonatal sepsis. We report invasive pneumococcal infection in three neonates. The infections were abrupt, severe, and rapidly progressive in two neonates with fatal outcome despite antibiotic therapy. There was no identifiable risk factor. Maternal colonization should be further studied.

Early immunological predictors of neurodevelopmental outcomes in HIV-infected children.

BACKGROUND: A previous analysis of children infected with human immunodeficiency virus (HIV) in the Women and Infants Transmission Study showed a strong correlation between low activated CD8(+) T lymphocytes in the first 2 months of life and good immunological prognosis. We sought to extend these observations to neurodevelopmental prognosis. METHODS: Ninety-eight HIV-infected children born before 1994 with flow cytometric data from the first 2 months of life and adequate neurodevelopmental testing through age 30 months were studied. Children were divided into those with low (5% CD8(+)HLA-DR(+) cells or >25% CD8(+)CD38(+) cells) immune activation at 1 and/or 2 months of age. Analysis was performed using survival analysis, Cox's proportional hazard regression, and longitudinal regression models. RESULTS: Absence of immune activation, measured as

Hospital-based epidemiologic survey of malignancies in children infected with human immunodeficiency virus in Thailand.

To determine the incidence and spectrum of malignancies in human immunodeficiency virus-infected children, we surveyed 48 hospitals in Thailand between 1996 and 2000. There were 23 children (14 boys and 9 girls; average age at diagnosis of malignancy, 4.2 years), and the incidence rate was 0.6 per 1000 person-years. The most common malignancy was lymphoma (87.0%). The prognosis was poor.

Reduced-dose intradermal vaccination against hepatitis A with an aluminum-free vaccine is immunogenic and can lower costs.

A reduced dose (0.1 mL) of intradermal hepatitis A virus (HAV) vaccine could facilitate the control of hepatitis A in countries of endemicity. All study subjects receiving an aluminum-free HAV vaccine intradermally were seroprotected 28 days after vaccination (anti-HAV titer, > or =10 mIU/mL). Seroprotection rates decreased to 80.8% at 12 months but returned to 100%, with titers increasing 28-fold, after receipt of a booster vaccination.

Childhood shigellosis at King Chulalongkorn Memorial Hospital, Bangkok, Thailand: a 5-year review (1996-2000).

The objective of this study was to evaluate the demographic data and clinical presentation of childhood shigellosis, and to study the microbiological data and antimicrobial susceptibilities of Shigella spp. Nine thousand nine hundred fourteen stool culture specimens from children aged 0-15 years who were treated at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, between 1996 and 2000 were retrospectively reviewed. Data were collected from microbiological records and medical charts of childhood shigellosis in terms of demographic data, symptoms, signs, and complications of the patients, and the species and antimicrobial susceptibilities of the organisms. The data were analyzed in terms of means, ranges, and percentages. Of 1,523 children whose stool cultures were positive for pathogenic bacteria, 80 (5.3%) were infected with Shigella spp; 34 females and 46 males. The age distribution ranged from 1 day to 13 years with a mean age of 3.6 years. Common clinical presentations included diarrhea (96.6%), fever (77.6%) and vomiting (44.8%); seizures were the most common complication found (27.6%). Watery and mucous were the most common characteristics of stools. The major Shigella spp found was S. sonnei (62.8%), which was susceptible to co-trimoxazole, ampicillin, cefazolin and ciprofloxacin in 2.3, 84.1, 100 and 100%, respectively. A short course of quinolones or oral cephalosporins should be recommended for the treatment of childhood shigellosis in areas with low susceptibility rates to co-trimoxazole and ampicillin.

Concomitant dengue infection and Kawasaki disease in an infant: a case report and literature review.

A previously healthy 11-month-old girl presented with fever and rash for 6 days. Physical examination revealed an irritable infant with a high fever, injected conjunctivae, red cracked lips, posterior auricular lymphadenopathy, hepatomegaly, generalized erythematous maculopapular rash and petechial hemorrhage on trunk, face and extremities. Complete blood count showed atypical lymphocytosis and thrombocytopenia. Dengue infection was initially diagnosed. The persistent fever and clinical manifestations of Kawasaki disease (KD) were observed on day 8 with high erythrocyte sedimentation rate (56 mm/hr). Treatment of KD included intravenous immunoglobulin on day 9 of the illness. Desquamation of the fingers was found on day 15 of the illness. Ectasia of left coronary artery with small aneurysmal dilatation was detected by echocardiography on day 15 of the illness. Hemagglutination-inhibition test and enzyme-linked immunosorbent assay for dengue virus eventually showed a four-fold rising. According to the literature review, this is the second reported case of dengue infection concomitant with KD. The natural course of each disease may be modified and causes some difficulties in diagnosis and management.

Serum and urine sodium levels in dengue patients.

We evaluated serum and urine sodium levels in children with dengue infections. Children with acute febrile illness admitted to Bhumibol Adulyadej Hospital in Bangkok from January 1999 to January 2000 were enrolled. Serum and urine sodium levels were measured before initiating intravenous fluid therapy. Two milliliters of blood were obtained on admission and before discharge to test for anti-dengue virus antibody using the enzyme-linked immunosorbent assay technique. Hyponatremia was defined as a serum sodium level <130 mEq/l and depletion of circulatory volume was defined as a urine sodium level < 20 mEq/l. Out of 93 enrolled patients, 49 were categorized as dengue patients and 44 were as non-dengue patients. Six dengue patients developed shock whereas 43 patients did not. The mean serum sodium level was significantly lower in dengue patients compared to non-dengue patients (p-value < 0.0001). Hyponatremia was 9.7 times more common in dengue patients. Among dengue patients, the mean serum sodium level was significantly lower in shock patients compared to non-shock patients (p-value = 0.003). However, the prevalence of hyponatremia was not different between the two groups. The mean urine sodium level was significantly lower in dengue patients compared to non-dengue patients (p-value < 0.0001). A urine sodium level < or = 20 mEq/l was 8.1 times more common in dengue patients. Among dengue patients, the mean urine sodium level was not significantly different between shock and non-shock patients. In shock patients, a urine sodium level < or = 20 mEq/l was 7.6 times more common.

A phase IV open label study to assess the safety, tolerability and immunogenicity of a Haemophilus influenzae type B (Hib) CRM197 conjugated vaccine administered to healthy infants at 2, 4, and 6 months of age.

The objective of this prospective clinical study was to evaluate the safety, tolerability and immunogenicity of Chiron Hib vaccine (Vaxem Hib) in Thai infants. This trial was conducted at Bhumibol Adulyadej Hospital, Bangkok, Thailand from June to November 1999. Three intramuscular injections of the vaccine were given to 119 infants at 2, 4 and 6 months of age. Reactions and adverse events after the vaccination were recorded. Blood samples for anti-PRP antibody were collected before the first immunization, and after the second and third immunizations. After the second dose, 91% and 58% of the subjects had anti-PRP antibody titers of > or =0.15 microg/ml and > or =1.0 microg/ml, respectively. After the third dose, 99% and 90% of the subjects had anti-PRP antibody titer > or =0.15 mcirog/ ml and > or =1.0 microg/ml, respectively. Local and systemic reactions were mild and transient. The study indicates that Vaxem Hib vaccine is safe and well tolerated. Three doses of the vaccine are necessary to achieve adequate protection in infants.

Hospital-based epidemiology of childhood cholera: a 6-year review in a university hospital in Bangkok, Thailand.

BACKGROUND: Cholera is the cause of severe acute watery diarrhea. Without proper fluid therapy, severe cholera kills half of the affected patients. In terms of epidemiology and surveillance, up-to-date information of this disease in each country is essential. OBJECTIVES: To evaluate 1) prevalence, serogroups, serotypes and antimicrobial susceptibility pattern of V cholerae, and 2) demographic data and clinical manifestation of pediatric patients with cholera. MATERIAL AND METHOD: Microbiogical records of children aged 0-15 years with cholera, who were treated at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, between January 1995 and December 2000 were retrospectively reviewed Serogroups, serotypes, and antimicrobial susceptibility of V. cholerae were studied Medical records of children with positive stool cultures for V. cholerae were reviewed in terms of demographic data, clinical manifestation of the patients. RESULTS: Of 11,709 stool culture specimens, pathogenic bacteria were found in 1,745 specimens and 95 specimens (5.4%) were positive for V. cholerae. V. cholerae O1 and non-O1/non-O139 were found in 52.6% and 47.4%, respectively. Common serotypes of V. cholorae O1 were Ogawa. Antimicrobial susceptibility of the pathogens to co-trimoxazole, ampicillin, ceftriaxone, ciprofloxacin and gentamicin were 55.0%, 56.4%, 91.4%, 92.5% and 94.9%, respectively. Age distribution of the patients ranged from 2 months to 15 years with an average age of 2.92 years. Clinical manifestations included acute watery diarrhea (92.8%), vomiting (56.4%), fever (37.5%), hypotension (19.6%) and abdominal pain (3.8%). Stool leukocytes were microscopically detected in 20% of the patients. No patients died in the present study. CONCLUSION: Childhood cholera in Thailand still exists. Most patients presented with acute watery diarrhea. Regarding antimicrobial susceptibility pattern, ceftriaxone and quinolones are appropriate drugs of choice.

Acceptability of oral typhoid vaccine in Thai children.

To determine the acceptability of oral typhoid vaccine to Thai children, 434 volunteers, aged 4-15 years (average age = 8.2 years), were assigned to take three capsules of oral typhoid vaccine (one capsule every other day). Success was defined as the subjects' being able to swallow all three capsules. Information concerning the subjects' level of education, eating habits, and ability to take medicines in a variety of preparations (syrups, tablets and capsules) was obtained. The overall success rate was 94.2%; the rates were 84.4%, 94.9%, and 100% in the age groups 4-6 years, 7-9 years, and 10-12 years respectively. The rates were 82%, 85.7%, 93.3%, 96.4%, 98.8%, 100% and 100% in the students of kindergarten 1, kindergarten 2, elementary grade 1, grade 2, grade 3, grade 4, and grade 5 respectively. There was a correlation between a child's prior ability to take tablets/capsules and his success in swallowing the oral typhoid vaccine.

Risk factors for Epstein-Barr virus infection in Thai infants.

To identify the risk factors for Epstein-Barr virus (EBV) infection among infants in Bangkok, Thailand, a case-control study was conducted during 1997-1999. Blood samples were collected from 257 Thai infants aged 6 months to 2 years. Serum samples were assayed for specific EBV IgG antibodies based on a commercial enzyme-linked immunosorbent assay kit. The subjects' parents were interviewed with structured questionnaires to collect details about their infants' age, sex, socioeconomic background, and place of child rearing. The infants were classified into two groups: positive and negative EBV IgG; factors related to the risks of infection were also determined. The overall seropositivity rate of the study infants was 36.2%. Infants aged 1-2 years had a 3.64 times higher risk than those aged 6 months -1 year (p < 0.0001). Infants living in families with an income of < or = 10,000 baht/month (1 US dollar = 42 baht) had a 1.33 times higher risk than those with a family income of >10,000 baht/month (p = 0.03). Infants who were reared at home had a 2.92 times higher risk than those reared outside the home (p = 0.05). By logistic regression analysis, age (> 1 years) and family income (< or = 10,000 baht/month) were the two risk factors associated with EBV infection.