Clinical and epidemiological characteristics of acute respiratory virus infections in Vietnamese children.

Information about viral acute respiratory infections (ARIs) is essential for prevention, diagnosis and treatment, but it is limited in tropical developing countries. This study described the clinical and epidemiological characteristics of ARIs in children hospitalized in Vietnam. Nasopharyngeal samples were collected from children with ARIs at Ho Chi Minh City Children's Hospital 2 between April 2010 and May 2011 in order to detect respiratory viruses by polymerase chain reaction. Viruses were found in 64% of 1082 patients, with 12% being co-infections. The leading detected viruses were human rhinovirus (HRV; 30%), respiratory syncytial virus (RSV; 23·8%), and human bocavirus (HBoV; 7·2%). HRV was detected all year round, while RSV epidemics occurred mainly in the rainy season. Influenza A (FluA) was found in both seasons. The other viruses were predominant in the dry season. HRV was identified in children of all age groups. RSV, parainfluenza virus (PIV) 1, PIV3 and HBoV, and FluA were detected predominantly in children aged 24 months, respectively. Significant associations were found between PIV1 with croup (P < 0·005) and RSV with bronchiolitis (P < 0·005). HBoV and HRV were associated with hypoxia (P < 0·05) and RSV with retraction (P < 0·05). HRV, RSV, and HBoV were detected most frequently and they may increase the severity of ARIs in children.

Human rhinovirus infections in hospitalized children: clinical, epidemiological and virological features.

Molecular epidemiology and clinical impact of human rhinovirus (HRV) are not well documented in tropical regions. This study compared the clinical characteristics of HRV to other common viral infections and investigated the molecular epidemiology of HRV in hospitalized children with acute respiratory infections (ARIs) in Vietnam. From April 2010 to May 2011, 1082 nasopharyngeal swabs were screened for respiratory viruses by PCR. VP4/VP2 sequences of HRV were further characterized. HRV was the most commonly detected virus (30%), in which 70% were diagnosed as either pneumonia or bronchiolitis. Children with single HRV infections presented with significantly higher rate of hypoxia than those infected with respiratory syncytial virus or parainfluenza virus (PIV)-3 (12·4% vs. 3·8% and 0%, respectively, P < 0·05), higher rate of chest retraction than PIV-1 (57·3% vs. 34·5%, P = 0·028), higher rate of wheezing than influenza A (63·2% vs. 42·3%, P = 0·038). HRV-C did not differ to HRV-A clinically. The genetic diversity and changes of types over time were observed and may explain the year-round circulation of HRV. One novel HRV-A type was discovered which circulated locally for several years. In conclusion, HRV showed high genetic diversity and was associated with significant morbidity and severe ARIs in hospitalized children.

Evaluation of immunochromatography tests for detection of novel GII.17 norovirus in stool samples.

A novel GII.17 norovirus has emerged as a major cause of epidemic and endemic acute gastroenteritis in several countries in Asia. We used a small panel of stool samples in which GII.17 virus had been quantified by real-time RT-PCR to evaluate four commercially available norovirus immunochromatography (IC) kits. At least 10(8) copies/mL of GII.17 virus were required by each IC kit for a positive result, which is 1,000-fold more than that reported for these assays for GII.4 viruses.

Prevalence, seasonality, and peak age of infection of enteric adenoviruses in Japan, 1995-2009.

A total of 7185 faecal specimens collected from infants and children with gastroenteritis in seven different regions of Japan during 1995-2009 were examined for adenovirus by polymerase chain reaction. Adenovirus was detected in 568 (7.9%) patients. The adenovirus activity peak was in winter and spring seasons (December-March) during the study period in the Japanese paediatric population. During the last 15 years, adenovirus 41 was the most predominant strain in Japan.

Seasonal pattern and genotype distribution of sapovirus infection in Japan, 2003-2009.

Sapovirus, a member of the family Caliciviridae, is one of the major causative agents of viral gastroenteritis affecting all age groups. A total of 3232 faecal specimens collected from infants and children with gastroenteritis in five different regions of Japan during 2003-2009 were examined for sapovirus by reverse transcription-polymerase chain reaction. Sapoviruses were detected in 131 (4·05%) patients with the peak observed mainly in the cold season (November-March) in Japan during 2003-2009. During the last 6 years, sapovirus GI/1 was the predominant strain in Japan followed by GIV, GII/3, GII/6, GII/2, GII/12 and GI, respectively.

Genetic characterization of group C rotavirus isolated from a child hospitalized with acute gastroenteritis in Chiang Mai, Thailand.

During an epidemiological survey of human rotavirus infection in Chiang Mai, Thailand, from 2002 to 2004, in which 263 stool specimens tested, one isolate of group C rotavirus was detected from a two-year-old child admitted to hospital with acute gastroenteritis. The human group C rotavirus, named CMH004/03, was characterized further by molecular analyses of its VP4, VP6, and VP7 gene segments as well as determination of RNA pattern by polyacrylamide gel electrophoresis (PAGE). Molecular characterization of VP4, VP6, and VP7 genes by sequence analyses showed high levels of sequence identities with those of human group C rotavirus reference strains isolated worldwide at 95.2% to 99.4% on nucleotide and 97.5% to 100% on amino acid levels. In contrast, the CMH004/03 strain exhibited far lesser nucleotide and amino acid sequence identities at 67.7% to 84.1% and 68.7% to 91.3%, respectively, when compared with those of porcine and bovine group C rotaviruses. Phylogenetic analyses of VP4, VP6, and VP7 genes clearly confirmed that the CMH004/03 strain clustered in a monophyletic branch with other human group C rotavirus reference strains and distantly related to the clusters of animal group C rotavirus strains. In addition, the RNA electrophoretic migration pattern of CMH004/03 showed a typical pattern (4-3-2-2) of group C rotavirus. To our knowledge, this study is the second report of group C rotavirus infection in pediatric patients in Thailand after it was reported for the first time about two decades ago.

Use of sequence analysis of the VP4 gene to classify recent Vietnamese rotavirus isolates.

Twenty-eight strains of P(8), four of P(4) and one of P(19) rotavirus, isolated in Ho Chi Minh City, Vietnam, during 2002-2003, were investigated by sequence analysis of the VP4 gene. Seven of the 28 P(8) rotavirus VP4 sequences clustered in the P(8)-3 lineage, or the rare, so-called OP354-like lineage. Amino-acid sequence comparison revealed that Vietnamese P(8)-3 rotaviruses were generally very similar to Malawian strains, including the prototype OP354 strain. The numerical severity scores of diarrhoeal disease caused by the Vietnamese P(8)-3 rotaviruses were statistically higher than those of diarrhoeal disease caused by rotaviruses in the more common P(8)-2 lineage. Sequence and phylogenetic analysis of the VP4 gene of a Vietnamese G9P(19) rotavirus isolate showed a high degree of homology with the cognate genes of other human and porcine rotaviruses, including the prototype 4F strain.

Emergence of rare sapovirus genotype among infants and children with acute gastroenteritis in Japan.

A total of 1,154 fecal specimens from infants and children with acute gastroenteritis in five cities in Japan (Maizuru, Tokyo, Sapporo, Saga, and Osaka), collected from July 2003 to June 2005, were tested for the presence of diarrheal viruses by reverse transcriptase multiplex PCR. Overall, 469 of 1,154 (40.6%) were positive for diarrheal viruses, of which 49 (10.4%) were positive for sapovirus. The peak of sapovirus infection shifted from April-June in 2003-2004 to October-December in 2004-2005. The observations show that maximum sapovirus prevalence can occur during warmer seasons. Sapovirus was subjected to molecular genetic analysis by sequencing. The results indicated that sapovirus genogroup I was a dominant group (100%). Sapovirus strains detected in this study were further classified into four genotypes (GI/1, GI/4, GI/6, and GI/8). Of these, sapovirus GI/1 was the most predominant, followed by sapovirus GI/6; these accounted for 93% (13 of 14) and 7% (1 of 14), respectively, in 2003-2004. However, it was noteworthy that sapovirus GI/6 suddenly emerged to become the leading genotype, accounting for 77% (27 of 35) of isolates in 2004-2005. This is believed to be the first report of the changing distribution of sapovirus genotypes and of the emergence of the rare sapovirus GI/6.

Changing distribution of group A rotavirus G-types and genetic analysis of G9 circulating in Japan.

A total of 1,797 fecal specimens from infants and children with acute gastroenteritis in Japan from July 2000 to June 2003 were tested for group A rotavirus by ELISA, RT-PCR, RNA-PAGE and latex agglutination methods. Of these, 439 were found to be positive for group A rotavirus and this presented 24.4%. In 2000-2001, G1 was the most prevalent (45.5%) followed by G2 (32.5%), G3 (12.3%), G9 (5.9%) and G4 (2.6%). However, G2 was found predominant with 40% in the following year (2001-2002). Interestingly, G9 had a rapid increase of infection up to 17.8%. In 2002-2003, G3 dominated over other G-types with 34%. Another interesting feature of the study was the demonstration of great genetic diversity among G9 strains in Japan. Worth of note was the first prevalence pattern of rotavirus G-types with an increase of G2, G3 as well as G9 and a decrease of G1 during the 20 year-survey of rotavirus infection in Japan.

Existence of multiple outbreaks of viral gastroenteritis among infants in a day care center in Japan.

A total of 921 fecal specimens collected from 44 infants in a day care center (DCC) in Tokyo, Japan during June 1999 to July 2000 were tested for the presence of rotavirus, norovirus, sapovirus, astrovirus and adenovirus by reverse-transcription-multiplex polymerase chain reaction (RT-multiplex PCR) and sequence analysis. Of 88 fecal specimens from infants with acute gastroenteritis, 51.1% (45) were found to be positive for diarrheal viruses. Astrovirus was the most prevalent (15.9%, 14 of 88), followed by norovirus GII (14.8%, 13 of 88), adenovirus (12.5%, 11 of 88), and sapovirus (2.3%, 2 of 88). Viral mixed infection accounted for 5.7% (5 of 88). Interestingly, 230 of 833 (27.6%) fecal specimens collected from asymptomatic infants were also infected with diarrheal viruses. Of these, astrovirus, norovirus GII, adenovirus and sapovirus were identified in 53, 46, 96 and 22 fecal specimens (23%, 20%, 41.7%, and 9.6%, respectively). Moreover, 13 of 833 (1.6%) normal specimens showed mixed viral infections. Surprisingly, no rotavirus (known as the most common causative agent of acute gastroenteritis in DCCs) was detected in those subjects. Another interesting feature was the demonstration of five separate outbreaks of acute gastroenteritis identified in a single DCC. Outbreak A was associated with both astrovirus serotype 1 and norovirus GII/3 (known as Toronto virus cluster); Outbreak B with adenovirus 12; Outbreak C with norovirus GII/4 (Lordsdale virus cluster); Outbreak D with sapovirus GIV and Outbreak E with astrovirus serotype 1. To our knowledge, this is the first proof of multiple outbreaks of viral gastroenteritis in Japanese infants in a single DCC. Our results confirm the presence as well as the importance of these viruses and warn of the threat they pose.

Etiologic agents of acute gastroenteritis among Japanese infants and children: virus diversity and genetic analysis of sapovirus.

A total of 371 fecal specimens from infants and children with acute gastroenteritis in Maizuru, Tokyo and Osaka, Japan from July 2002 to June 2003 were tested for the presence of diarrheal viruses by reverse transcription-polymerase chain reaction (RT-PCR), reverse passive hemagglutination (PRHA), RNA-polyacrylamide gel electrophoresis (PAGE), latex agglutination and sequence analysis methods. Among diarrheal viruses detected, group A rotavirus was the most prevalent (42.2%) followed by norovirus (28.9%), group C rotavirus (8.4%), sapovirus (6.7%), adenovirus (5.3%) and astrovirus (0.9%), respectively. There was the high rate (7.6%) of viral mixed infections. Sapovirus was classified into 6 genotypes (GI/1, GI/4, GI/5, GI/6 and GII/1 and one novel tentatively called GII/5). It is noteworthy that genogroup II sapovirus can be classified into 5 genotypes. Our findings confirmed the presence of many diarrheal viruses co-circulating among Japanese infants and children and showed the great genetic diversity among sapoviruses.

A novel RT-multiplex PCR for enteroviruses, hepatitis A and E viruses and influenza A virus among infants and children with diarrhea in Vietnam.

A novel reverse transcription-multiplex polymerase chain reaction (RT-multiplex PCR) assay that can detect enteroviruses, hepatitis A and E viruses and influenza A virus from various hosts (avian species, human, swine and horse) was developed. The identification of that group of viruses was performed with the mixture of four pairs of published specific primers (F1 and R1, P3 and P4, 2s and 2as, MMU42 and MMU43) for amplifying viral genomes and specifically generated four different amplicon sizes of 440, 267, 146 and 219 bp for enteroviruses, hepatitis A and E viruses and influenza A virus, respectively. A total of 276 fecal specimens (previously screened for rotavirus, adenovirus, norovirus, sapovirus and astrovirus-negative) from infants and children admitted into hospital with acute gastroenteritis in Ho Chi Minh city, Vietnam during October 2002 and September 2003 were collected and further tested for the presence of those viruses by RT-multiplex PCR. Enteroviruses were identified in 27 specimens and this represented 9.8%. No hepatitis A and E viruses and influenza A virus was found among these subjects. The sensitivity and specificity of RT-multiplex PCR were also assessed and demonstrated the strong validation against RT-monoplex PCR. Taken together, the findings clearly indicated that this novel RT-multiplex PCR is a simple and potential assay for rapid, sensitive, specific and cost-effective laboratory diagnosis to investigate molecular epidemiology of acute gastroenteritis caused by enteroviruses, hepatitis A and E viruses and influenza A virus. This report is the first, to our knowledge, detecting these kinds of viruses in diarrheal feces from infants and children in Vietnam.

Genetic diversity of sapovirus in fecal specimens from infants and children with acute gastroenteritis in Pakistan.

A total of 517 fecal specimens collected from infants and children with acute gastroenteritis in Karachi city, Pakistan during 1990-1994 were examined for the presence of sapovirus by RT-PCR and sequence analysis methods. Sapovirus was identified in 17 of 517 (3.2%) specimens. Sapovirus was further clustered into three distinct genogroups (I, II and IV) and these presented 70.6%, 23.5% and 5.9%, respectively. Our results clearly indicated that sapovirus could be classified into 7 GI and 4 GII genotypes. It was noteworthy to point out that sapovirus detected among Pakistani infants and children with acute gastroenteritis demonstrated the great genetic diversity and presented novel sapovirus genotypes.

Detection of norovirus and sapovirus infection among children with gastroenteritis in Ho Chi Minh City, Vietnam.

This report describes norovirus (NoV) and sapovirus (SaV) infections in hospitalized children with acute sporadic gastroenteritis in Ho Chi Minh City, Vietnam. Stool specimens collected between December 1999 and November 2000 were examined for NoV and SaV using reverse transcription-PCR and phylogenetic analysis. NoVs were detected in 72 of 448 rotavirus-negative specimens, counted as part of an overall annual detection rate of 5.4% (72 of 1,339 children). This included four NoV genogroup I (GI) strains and 68 NoV GII strains. Only one SaV GI strain was detected in the rotavirus-negative specimens. Over 73% of the NoV sequences belonged to GII/4 (Lordsdale cluster) and were detected in all months except March. We also detected GII/3 strains (Saitama U201 cluster), a naturally occurring recombinant NoV, between January 2000 and March 2000 but not after this period. Other NoV strains belonging to GI/4, GI/8, GII/1, and GII/7 were also detected but were infrequent. In addition, two almost identical NoV GII strains (strains 026 and 0703) collected six months apart were classified into a new genotype that includes the Mc37 strain, which was previously shown to be a recombinant NoV. During this one-year study, the NoV prevailed at the end of the rainy season and the beginning of the dry season. Further epidemiological studies may be necessary to determine whether the GII/4 strains continue to dominant in this region.

Increased subglottic gallium uptake in relapsing polychondritis.

Gallium scintigraphy was performed on a 14-yr-old girl with subglottic airway narrowing that caused wheezing and dyspnea. The study showed increased gallium uptake in the neck. A biopsy was performed on the subglottic region, and the histology was compatible with relapsing polychondritis. After treatment with steroids, laboratory data that had indicated active inflammation soon normalized. Repeat gallium scintigraphy showed diminished uptake, although the subglottic stenosis did not improve. These results suggest that gallium scintigraphy is valuable for evaluating inflammatory activity in relapsing polychondritis.

[123I-metaiodobenzylguanidine (MIBG) scintigraphy for the staging of neuroblastoma].

Nineteen children with neuroblastoma (aged 2 w.-7 y.o.) were studied to evaluate the optimal scan conditions for Iodine-123-Metaiodobenzylguanidine (MIBG) scintigraphy for accurate staging at the time of diagnosis. Six and 24 hours after an injection of 123I-MIBG, whole body image and truncal spot and SPECT images were obtained. Compared with other studies (CT or MRI and bone scintigraphy), each 123I-MIBG image was evaluated visually to investigate which image can demonstrate the extent of neuroblastoma most exactly. MIBG images demonstrated primary tumors in all patients, and metastatic lymphadenopathy in 8 of 9 patients. Twenty-four hour SPECT images gave us the most detailed information about the extent of abnormal accumulation. As to bone and bone marrow lesions, 6 hour images were superior to 24 hour images in detectability. Moreover, MIBG showed many more lesions and more extended accumulation than the bone scan. 123I-MIBG scintigraphy was very useful in detecting neuroblastomas. In order to get the most valuable information, both delayed SPECT and early whole body planar images should be obtained.

[Evaluation of multislice dynamic MR imaging of the whole liver by inversion recovery snap shot FLASH method].

We acquired dynamic images over the whole liver by inversion recovery snap shot FLASH method after a bolus intravenous injection of Gadolinium-DTPA. Each nodule of hepatoma in the liver showed early enhancement and gradually turned to show low intensity. In two cases of hepatoma, small intrahepatic metastases, which were not detected by US, CT and spin-echo image of MRI, were suspected as high intensity nodules on early phase. Also recurrent areas after TAE were enhanced on early phase. This method is practical for improving the detection of lesions and is useful for evaluating the recurrence after TAE.

Detection of serum antibody by the antimitogen assay against streptococcal erythrogenic toxins. Age distribution in children and the relation to Kawasaki disease.

We describe a new method to measure human serum antibody against streptococcal erythrogenic toxins that uses inhibition of lymphocyte mitogenicity of the toxins as the indicator. Sera from 53% of 53 Kawasaki disease patients contained specific inhibitory activity against A toxin, whereas only 15% had serum inhibitory activity against B toxin. The specific anti-A toxin serum inhibitor was found in 10% of 118 age-matched control patients suffering from various infections and allergic diseases (p = 0.001, compared to Kawasaki disease patients). Serum inhibitory activity was detected in a small number of patients with beta-hemolytic streptococcal infection (3/19) and in none of the age-matched healthy children (0/17). However, four of seven cord blood sera samples and five of 13 sera samples from healthy neonates contained the inhibitor, a result suggesting passive transfer from mothers. Most of the antimitogen-positive sera were also positive by ELISA of IgG antibody against A toxin, and IgG fractions of the positive sera remained positive in both assays. Thus, it is possible that the specific serum inhibitor detected by the antimitogen assay represents anti-A toxin antibody. The role of toxin-producing bacteria in the pathogenesis of Kawasaki disease remains to be investigated.

Production of interleukin-1-alpha and -beta by human peripheral polymorphonuclear neutrophils.

The mechanism of the production of interleukin-1 (IL-1) by human peripheral polymorphonuclear neutrophils (PMN) was investigated. Supernatants of PMN stimulated with 30 micrograms/ml lipopolysaccharide (LPS) were used as extracellular IL-1 and supernatants of their lysate as intracellular IL-1 source. IL-1 activity was measured by the C3H/HeJ thymocyte co-mitogenic assay. The supernatants from PMN stimulated with LPS for 72 h showed IL-1 activity which had an apparent molecular weight of 15-20 kilodaltons and pI of 5.0 and more than 8.5. It was neutralized with anti-IL-1 antibodies and it lacked IL-2 activity. Our time course study of the IL-1 assay with neutralization by anti-IL-1-alpha and -beta antibodies indicated that the extracellular IL-1-beta activity appeared predominantly in the early incubation periods, whereas alpha activity appeared predominantly in the late periods. Intracellular IL-1-alpha but not beta activity was detected mainly at the intermediate incubation periods. These data indicate that PMN stimulated with LPS produce both IL-1-alpha and -beta, and release IL-1-beta first and IL-1-alpha later.