Whole genome sequencing of Streptococcus suis revealed potential drug resistance and zoonotic transmission in companion cat.

Streptococcus suis is a bacterium of clinical importance in diverse animal hosts including companion animals and humans. Companion animals are closely associated in the living environment of humans and are potential reservoirs for zoonotic pathogens. Given the zoonotic potential of S. suis, it is crucial to determine whether this bacterium is present among the companion animal population. This study aimed to detect Streptococcus suis in companion animals namely cats and dogs of the central west coast of Peninsular Malaysia and further characterize the positive isolates via molecular and genomic approach. The detection of S. suis was done via bacterial isolation and polymerase chain reaction assay of gdh and recN gene from oral swabs. Characterization was done by multiplex PCR serotyping, as well as muti-locus sequence typing, AMR gene prediction, MGE identification and phylogenomic analysis on whole genome sequence acquired from Illumina and Oxford Nanopore sequencing. Among the 115 samples, PCR assay detected 2/59 of the cats were positive for S. suis serotype 8 while all screened dog samples were negative. This study further described the first complete whole genome of S. suis strain SS/UPM/MY/F001 isolated from the oral cavity of a companion cat. Genomic analysis revealed a novel strain of S. suis having a unique MLST profile and antimicrobial resistance genes of mefA, msrD, patA, patB and vanY. Mobile genetic elements were described, and pathogenic determinants matched to human and swine strains were identified. Phylogenetic tree analysis on the core genome alignment revealed strain SS/UPM/MY/F001 was distinct from other S. suis strains. This study provided insight into the detection and genomic features of the S. suis isolate of a companion cat and highlighted its potential for antimicrobial resistance and pathogenicity.

Epidemiological risk factors and phylogenetic affinities of Sarcocystis infecting village chickens and pigs in Peninsular Malaysia.

The intake of food and water containing the Sarcocystis parasite has been linked to a number of outbreaks worldwide, including Malaysia. Nevertheless, the lack of surveys and epidemiological data on Sarcocystis infections in Malaysia makes it difficult to estimate its occurrence in humans and animals. A cross-sectional study was conducted to determine the prevalence of Sarcocystis and the risk factors associated with infection among village chickens and pigs reared under different farm managements in Peninsular Malaysia. Phylogenetic trees were constructed using partial fragments of the 18S rRNA gene and ITS1 sequences. In the present study, 680 sera samples were collected from village chickens (n=250) and commercial pigs (n=433) and anti-Sarcocystis antibodies were screened using the enzymelinked immunosorbent assays (ELISA) kit. At the animal level, the prevalence of Sarcocystis was 9.2% (95% CI: 5.92-13.48) and at the farm level, it was 64.0% (95% CI: 42.52-82.03) in village chickens. The animal-level seroprevalence of Sarcocystis for pigs was 3.7% (95% CI: 2.13-5.93) and 36.8% (95% CI: 16.29-61.64) at the farm-level. Polymerase Chain Reaction (PCR) was conducted on meat samples from various parts of village chickens (n=250) consisting of brain, heart, lung, and pectoralis muscle tissues, and pork (n=121) consisting of intercostal muscle, diaphragm, and tongue. Sarcocystis DNA was detected in 6.4% (95% CI: 4.60-11.60) of village chicken samples but zero in pork samples. A total of 11 unique Sarcocystis haplotypes were isolated from these tissue samples. Multivariable logistic regression analysis of the putative risk factors showed a statistically significant association between Sarcocystis infection in pigs and uncovered storage of feed. Although no zoonotic Sarcocystis was isolated in this study, we reported the first discovery of S. wenzeli in Malaysia.

First molecular detection of porcine circovirus type 4 (PCV4) in Malaysia.

Porcine circovirus type 4 (PCV4) is the newest member in the porcine circovirus family, first reported in 2020. To date, the presence of PCV4 has only been reported in China, South Korea and most recently in Thailand. Detection of PCV4 have been reported in various production stages of pigs from piglets, finishers to sows; associated with a myriad of clinical manifestations including porcine dermatitis and nephropathy syndrome (PDNS), postweaning multisystemic wasting syndrome (PMWS), respiratory, enteric and neurological diseases. While successful virus isolation and culture has yet to be reported, pathogenicity of PCV4 has been demonstrated through infectious clone studies. The objective of this study is to investigate the presence of PCV4 in Malaysian porcine population to update the epidemiology of porcine circoviruses in Malaysia. A total of 49 samples from commercial intensive pig farms, abattoir and wild boar population were subjected to conventional polymerase chain reaction assay to detect PCV4 capsid (cap) genome. Resulting cap nucleotide sequences were analyzed for maximum likelihood phylogeny relationship. Results revealed that PCV4 is present in Peninsular Malaysia at a molecular prevalence of 4.08% (2 / 49 samples). Both PCV4 positive samples originated from clinically healthy finishers. Malaysian PCV4 strains were classified as genotype PCV4b, and were found to be phylogenetically distinct from the China, South Korea and Thailand strains. With this latest update of the novel PCV4 in Malaysia, it is clear that more attention needs to be given to the investigation of novel porcine circoviruses (PCV) and management of PCV diseases.

First molecular detection of porcine circovirus type 4 (PCV4) in Malaysia

@#Porcine circovirus type 4 (PCV4) is the newest member in the porcine circovirus family, first reported in 2020. To date, the presence of PCV4 has only been reported in China, South Korea and most recently in Thailand. Detection of PCV4 have been reported in various production stages of pigs from piglets, finishers to sows; associated with a myriad of clinical manifestations including porcine dermatitis and nephropathy syndrome (PDNS), postweaning multisystemic wasting syndrome (PMWS), respiratory, enteric and neurological diseases. While successful virus isolation and culture has yet to be reported, pathogenicity of PCV4 has been demonstrated through infectious clone studies. The objective of this study is to investigate the presence of PCV4 in Malaysian porcine population to update the epidemiology of porcine circoviruses in Malaysia. A total of 49 samples from commercial intensive pig farms, abattoir and wild boar population were subjected to conventional polymerase chain reaction assay to detect PCV4 capsid (cap) genome. Resulting cap nucleotide sequences were analyzed for maximum likelihood phylogeny relationship. Results revealed that PCV4 is present in Peninsular Malaysia at a molecular prevalence of 4.08% (2 / 49 samples). Both PCV4 positive samples originated from clinically healthy finishers. Malaysian PCV4 strains were classified as genotype PCV4b, and were found to be phylogenetically distinct from the China, South Korea and Thailand strains. With this latest update of the novel PCV4 in Malaysia, it is clear that more attention needs to be given to the investigation of novel porcine circoviruses (PCV) and management of PCV diseases.

Epidemiological risk factors and phylogenetic affinities of Sarcocystis infecting village chickens and pigs in Peninsular Malaysia

@#The intake of food and water containing the Sarcocystis parasite has been linked to a number of outbreaks worldwide, including Malaysia. Nevertheless, the lack of surveys and epidemiological data on Sarcocystis infections in Malaysia makes it difficult to estimate its occurrence in humans and animals. A cross-sectional study was conducted to determine the prevalence of Sarcocystis and the risk factors associated with infection among village chickens and pigs reared under different farm managements in Peninsular Malaysia. Phylogenetic trees were constructed using partial fragments of the 18S rRNA gene and ITS1 sequences. In the present study, 680 sera samples were collected from village chickens (n=250) and commercial pigs (n=433) and anti-Sarcocystis antibodies were screened using the enzymelinked immunosorbent assays (ELISA) kit. At the animal level, the prevalence of Sarcocystis was 9.2% (95% CI: 5.92-13.48) and at the farm level, it was 64.0% (95% CI: 42.52-82.03) in village chickens. The animal-level seroprevalence of Sarcocystis for pigs was 3.7% (95% CI: 2.13-5.93) and 36.8% (95% CI: 16.29-61.64) at the farm-level. Polymerase Chain Reaction (PCR) was conducted on meat samples from various parts of village chickens (n=250) consisting of brain, heart, lung, and pectoralis muscle tissues, and pork (n=121) consisting of intercostal muscle, diaphragm, and tongue. Sarcocystis DNA was detected in 6.4% (95% CI: 4.60-11.60) of village chicken samples but zero in pork samples. A total of 11 unique Sarcocystis haplotypes were isolated from these tissue samples. Multivariable logistic regression analysis of the putative risk factors showed a statistically significant association between Sarcocystis infection in pigs and uncovered storage of feed. Although no zoonotic Sarcocystis was isolated in this study, we reported the first discovery of S. wenzeli in Malaysia.

Molecular detection of porcine Enterocytozoon bieneusi infection in Peninsular Malaysia and epidemiological risk factors associated with potentially zoonotic genotypes.

Enterocytozoon bieneusi is an emerging opportunistic pathogen infecting humans, and both domestic and wild pigs are known to harbour zoonotic genotypes. There remains a paucity of information on the prevalence and epidemiology of this enteropathogen in Southeast Asia. The present study was undertaken to determine the molecular prevalence and risk factors associated with E. bieneusi infection among commercially farmed pigs in Malaysia. Faecal samples were collected from 450 pigs from 15 different farms and subjected to nested PCR amplification of the ribosomal internal transcribed spacer (ITS) gene of E. bieneusi. Phylogenetic analysis involved 28 nucleotide sequences of the ITS region of E. bieneusi. An interviewer-administered questionnaire provided information on the animal hosts, farm management systems and environmental factors and was statistically analysed to determine the risk factors for infection. The prevalence of E. bieneusi infection was relatively high (40.7%). The highest prevalence (51.3%) was recorded among the piglets, while the adults showed the lowest level of infection (31.3%). Multivariate analysis indicated that age of the pigs, distance of the farm from human settlement and farm management system were significant risk factors of infection. Three genotypes (EbpA, EbpC and Henan-III) detected among the pigs are potentially zoonotic. The high prevalence of E. bieneusi among locally reared pigs, the presence of zoonotic genotypes and the spatial distribution of pig farms and human settlements warrant further investigation on the possibility of zoonotic transmission.

Molecular detection of Haemophilus parasuis serotypes 4, 5 or 12 and 13 in Peninsular Malaysia.

Although the economic importance of Haemophilus parasuis infection causing Glasser's disease is prevalent throughout pig farms in Peninsular Malaysia, there is a dearth of knowledge on its actual nature. In this study, a multiplex PCR was performed to screen for three major predominant virulent strains of H. parasuis, which are serotypes 4, 5 or 12 and 13. A total of 175 tissues or bodily fluid samples of various parts were collected from diseased animals from October, 2016 to February, 2018; with total of 62.9% positive detection of H. parasuis. The highest detection was found to be in the pericardial sac fibrin (90.9%) followed by pleural fibrin, lung, pleural fluid, tonsil, pericardial sac, peritoneal fluid, abdominal fibrin, joint fluid, brain and pericardium. Serotype 13 was the highest (40/110) followed by serotype 4(37/110), serotype 5(31/110) and 12 samples were nontypable (12/110). The presence of untypable serotype also drives to further identification of other serotypes in Malaysia.

Molecular detection of Haemophilus parasuis serotypes 4, 5 or 12 and 13 in Peninsular Malaysia

@#Although the economic importance of Haemophilus parasuis infection causing Glasser’s disease is prevalent throughout pig farms in Peninsular Malaysia, there is a dearth of knowledge on its actual nature. In this study, a multiplex PCR was performed to screen for three major predominant virulent strains of H. parasuis, which are serotypes 4, 5 or 12 and 13. A total of 175 tissues or bodily fluid samples of various parts were collected from diseased animals from October, 2016 to February, 2018; with total of 62.9% positive detection of H. parasuis. The highest detection was found to be in the pericardial sac fibrin (90.9%) followed by pleural fibrin, lung, pleural fluid, tonsil, pericardial sac, peritoneal fluid, abdominal fibrin, joint fluid, brain and pericardium. Serotype 13 was the highest (40/110) followed by serotype 4(37/110), serotype 5(31/110) and 12 samples were nontypable (12/110). The presence of untypable serotype also drives to further identification of other serotypes in Malaysia.

Effects of branched chain amino acid supplementation on patient care outcomes in adults and children with liver cirrhosis: A systematic review.

BACKGROUND & AIMS: Malnutrition is highly prevalent in chronic liver disease (CLD) due to alterations in nutrient utilization, malabsorption and poor intake. Low serum concentrations of branched chain amino acids (BCAA) in the presence of elevated aromatic acid concentrations is commonly observed in adult and children with liver cirrhosis and is associated with malnutrition and other adverse patient outcomes. The efficacy of BCAA supplementation has not been well established in adults and children with CLD. The purpose of this review was to critically evaluate the literature regarding the impact of BCAA supplementation related to changes in body composition, muscle strength, liver biomarkers, medical and hepatic complications (hepatic encephalopathy (HE), ascites, edema) and patient care outcomes (event free survival, health related quality of life, length of hospitalization). METHODS: A total of 40 articles retrieved from PubMed or Web of Science databases (1989-2017) were included. RESULTS: BCAA supplementation may be beneficial in improving muscle strength, ascites and edema with potential clinically significant improvements in HE in adult liver patients. In children, limited data have shown that BCAA supplementation may exert favourable effects on weight, fat mass, fat free mass and serum albumin level. CONCLUSIONS: Heterogeneity of study findings attributed to variability in BCAA dose (total, relative proportions), duration, disease severity and lack of uniformity in tools used for assessing patient outcomes limit overall conclusions. Longitudinal studies examining the efficacy of BCAA supplementation as a therapeutic treatment of malnutrition in chronic liver disease is warranted.

Serological and molecular identification of Leptospira spp. in swine and stray dogs from Malaysia.

Leptospirosis is endemic in Malaysia with Leptospira species extensively isolated from domestic and wild animals. Rats were found to be the principal maintenance hosts followed by cattle, pigs, and dogs. The objectives of this study were to isolate and identify Leptospira serovars circulating among swine from three different farms and also from stray dogs and cats from Klang valley, Selangor, Malaysia. Urine and kidney samples collected from 150 stray dogs, 50 cats and 81 swine were inoculated into semi-solid Ellinghausen McCullough Johnson and Harris (EMJH) media supplemented with additional 5-Fluorouracil. Dark field microscopy revealed only one positive culture of Leptospira from dog and swine samples, but all cat samples were negative. The PCR technique using published primers detected 11 positives in urine samples of dogs and 5 positives from swine. The microscopic agglutination test (MAT) confirmed the presence of two serovars in both dog and swine populations namely, L. interrogans serovar Canicola and L. interrogans serovar Pomona (MAT > 100), with Not I-PFGE analyses separating these two serovars into distinct profiles. Despite the low prevalence in stray dogs, the latter may play an important role in the contamination of the environment. Swine can also pose a potential risk of infection to humans and other domestic animals, especially those living close to swine farms. Thus improving hygiene and eradication of rodents in swine farms are likely to reduce the risk of infection.

Different porcine reproductive and respiratory syndrome (PRRS) vaccine regimes and its effect on pig immunity status at Southeast Asia pig farms.

Porcine reproductive and respiratory syndrome (PRRS) is a disease characterised by late-term reproductive failure in sows and gilts, and respiratory problems in piglets and growing pigs. In this study, 240 sera were collected from four farms that had been practicing different PRRS vaccination regime for more than a year and vaccinations were done at 2 months before sampling. Fifteen sera samples from four age groups: sows, growers, weaners and piglets were collected from each farm and analysed using IDEXX PRRS X3 ELISA for PRRSV antibodies. Pooled serum samples were tested by using nested-PCR that enable the differentiation of Type I and Type II PRRSV. Out of 80 pooled serum samples, none were positive for PRRSV indicating all age groups were not viraemic after vaccination. Results by ELISA test showed all the farms were seropositive for PRRS. ELISA testing showed no significant difference between the farms except for Farm B which practised whole herd US MLV vaccination. Farm B showed significantly lower (p<0.05) S/P ratio in their piglet, grower and sow groups which suggest there was low virus circulation in herd. Farm A which practised US MLV on sow was the only farm found to have seronegative status in their weaners. Data indicates PRRS MLV vaccination will not cause viraemia post four weeks vaccination and whole herd MLV vaccination may help to reduce virus circulation in PRRS endemic farm.

Different porcine reproductive and respiratory syndrome (PRRS) vaccine regimes and its effect on pig immunity status at Southeast Asia pig farms

Porcine reproductive and respiratory syndrome (PRRS) is a disease characterised by late-term reproductive failure in sows and gilts, and respiratory problems in piglets and growing pigs. In this study, 240 sera were collected from four farms that had been practicing different PRRS vaccination regime for more than a year and vaccinations were done at 2 months before sampling. Fifteen sera samples from four age groups: sows, growers, weaners and piglets were collected from each farm and analysed using IDEXX PRRS X3 ELISA for PRRSV antibodies. Pooled serum samples were tested by using nested-PCR that enable the differentiation of Type I and Type II PRRSV. Out of 80 pooled serum samples, none were positive for PRRSV indicating all age groups were not viraemic after vaccination. Results by ELISA test showed all the farms were seropositive for PRRS. ELISA testing showed no significant difference between the farms except for Farm B which practised whole herd US MLV vaccination. Farm B showed significantly lower (p<0.05) S/P ratio in their piglet, grower and sow groups which suggest there was low virus circulation in herd. Farm A which practised US MLV on sow was the only farm found to have seronegative status in their weaners. Data indicates PRRS MLV vaccination will not cause viraemia post four weeks vaccination and whole herd MLV vaccination may help to reduce virus circulation in PRRS endemic farm.

Instrumental delivery and ultrasound : a multicentre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery.

OBJECTIVE: To determine whether the use of ultrasound can reduce the incidence of incorrect diagnosis of the fetal head position at instrumental delivery and subsequent morbidity. DESIGN: Two-arm, parallel, randomised trial, conducted from June 2011 to December 2012. SETTING: Two maternity hospitals in the Republic of Ireland. SAMPLE: A cohort of 514 nulliparous women at term (≥37 weeks of gestation) with singleton cephalic pregnancies, aiming to deliver vaginally, were recruited prior to an induction of labour or in early labour. METHODS: If instrumental delivery was required, women who had provided written consent were randomised to receive clinical assessment (standard care) or ultrasound scan and clinical assessment (ultrasound). [Correction added on 17 April 2014, after first online publication: Sentence was amended.] MAIN OUTCOME MEASURE: Incorrect diagnosis of the fetal head position. RESULTS: The incidence of incorrect diagnosis was significantly lower in the ultrasound group than the standard care group (4/257, 1.6%, versus 52/257, 20.2%; odds ratio 0.06; 95% confidence interval 0.02-0.19; P < 0.001). The decision to delivery interval was similar in both groups (ultrasound mean 13.8 minutes, SD 8.7 minutes, versus standard care mean 14.6 minutes, SD 10.1 minutes, P = 0.35). The incidence of maternal and neonatal complications, failed instrumental delivery, and caesarean section was not significantly different between the two groups. CONCLUSIONS: An ultrasound assessment prior to instrumental delivery reduced the incidence of incorrect diagnosis of the fetal head position without delaying delivery, but did not prevent morbidity. A more integrated clinical skills-based approach is likely to be required to prevent adverse outcomes at instrumental delivery.

Surveillance of tuberculosis treatment outcomes of Singapore citizens and permanent residents, 2002-2011.

SETTING: Singapore, which had a tuberculosis (TB) incidence rate of 41 per 100,000 resident population in 2011. OBJECTIVE: To report the outcomes of Singapore citizens and permanent residents treated for TB from 2002 to 2011. METHODS: A computerised treatment surveillance module (TSM) was launched in 2001 to track the progress and outcome of TB patients nationally. Physicians were required to submit an electronic or paper return for every patient at each clinic visit. Treatment adherence, drugs prescribed, treatment delivery mode and final outcome, specified as 'completed treatment', 'lost to follow-up', 'death', 'transferred out', 'permanent cessation of treatment' and 'still on treatment/no final outcome', were captured. Quarterly cohort outcomes at 12-15 months after starting treatment were combined to generate annual treatment outcomes. RESULTS: Treatment completion rates increased from 73.4% to 82.8%. The proportion of patients lost to follow-up decreased from 3.4% to 1.7%, while that of patients still on treatment or with no final outcome decreased from 10.5% to 4.4%. The death rate ranged between 10.2% and 11.7%; the majority were not attributed to TB. CONCLUSION: TB treatment completion among Singapore citizens and permanent residents has improved since 2002 as the likely result of the TSM and other initiatives introduced over the past decade.

The entrapped and unravelled coronary wire.

No abstract available.

Genetic characterization of porcine circovirus 2 found in Malaysia.

BACKGROUND: Porcine circovirus type 2 is the primary etiological agent associated with a group of complex multi-factorial diseases classified as Porcine Circovirus Associated Diseases (PCVAD). Sporadic cases reported in Malaysia in 2007 caused major economic losses to the 2.2 billion Malaysian ringgit (MYR) (approximately 0.7 billion US dollar) swine industry. The objective of the present study was to determine the association between the presence of PCV2 and occurrences of PCVAD. RESULTS: This study showed that 37 out of 42 farms sampled were positive for PCV2 using PCR screening. Thirteen whole genome of PCV2 isolates from pigs with typical PCVAD symptoms were successfully sequenced. These isolates shared 98.3-99.2% similarities with sequences of isolates from The Netherlands. All thirteen isolates fell into the same clade as PCV2b isolates from other countries. Amino acid sequence analysis of the putative capsid protein (ORF2) of the PCV2 revealed that there are three clusters found in Malaysia, namely cluster 1C and 1A/1B. Of interest, three of the isolates (isolates Mal 005, Mal 006 and Mal 010) had a proline substitution for arginine or isoleucine encoded at nt. position 88-89. Eight of the isolates had mutations at the C terminus of the putative capsid protein suggestive of higher pathogenicity which may account for the high reports of PCVAD clinical symptoms in 2007. CONCLUSION: Phylogenetic study suggests that there may be a link between movements of animals by import of breeders into the country being the route of entry of the virus. While it is not possible to eradicate the virus from commercial pigs, the swine industry in Malaysia can be safeguarded by control measures implemented throughout the country. These measures should include improved biosecurity, disease surveillance; vaccination as well as enforcement of regulations formulated to control and prevent the spread of this disease on a national scale.

Home exposures to environmental tobacco smoke and allergic symptoms among young children in Singapore.

BACKGROUND: Research relating environmental tobacco smoke (ETS) exposures have focused on childhood asthma. There have been fewer studies with conflicting results performed on associations of ETS exposures with allergic symptoms. We are interested to see if ETS exposures in the homes are associated with allergic symptoms among preschool children in Singapore where public smoking is banned. METHODS: A cross-sectional study adopting an expanded and modified ISAAC (International Study on Asthma and Allergies in Childhood) questionnaire for the evaluation of asthma and allergies was conducted on 6,794 children attending 120 randomly selected child care centers. Specific information on demographics and ETS exposures was obtained. Adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) were determined using Poisson multivariate regression with a log-link function and robust variance estimates as recommended for cross-sectional studies. RESULTS: The response proportion was 70.0%, and 4,759 children from 97 centers participated. After adjusting for covariates, it was found that home ETS exposure was associated with increased risks of current symptoms of rhinitis (PR 1.23; 95% CI 1.01-1.50) and rhinoconjunctivitis (PR 1.79; 95% CI 1.26-2.54). These associations followed dose-response trends with respect to number of cigarettes smoked or smokers in the homes. Home ETS exposures were also associated with higher PRs of wheeze, nocturnal cough and doctor-diagnosed asthma. Compared with paternal smoking, higher risks of the above outcomes were found for maternal smoking. CONCLUSION: Home ETS exposure is a risk factor associated with rhinitis and asthma among preschool children.

The effect of ventilation strategies of child care centers on indoor air quality and respiratory health of children in Singapore.

UNLABELLED: This paper reports the effects of ventilation strategies on indoor air quality (IAQ) and respiratory health of children within 104 child care centers (CCCs) in a hot and humid climate. The CCCs were categorized by ventilation strategies: natural (NV), air-conditioned and mechanically ventilated (ACMV), air-conditioned using split units (AC), and hybrid (NV and AC operated intermittently). The concentration levels of IAQ parameters in NV CCCs are characterized by the influence of the outdoors and good dilution of indoor pollutants. The lower ventilation rates in air-conditioned CCCs result in higher concentrations of occupant-related pollutants but lower outdoor pollutant ingress. This study also revealed lower prevalence for most asthma and allergy, and respiratory symptoms in children attending NV CCCs. In multivariate analyses controlled for the effects of confounders, the risk of current rhinitis among children is significantly higher if they attend mechanically ventilated CCCs compared to NV CCCs. Air-conditioned CCCs were also associated with higher adjusted prevalence ratio of severe phlegm and cough symptoms and lower respiratory illness. Finally, children attending CCCs with hybrid ventilation are at high risk for almost all the respiratory symptoms studied. PRACTICAL IMPLICATIONS: This large field study indicates that different ventilation strategies employed by child care centers can cause significant variations in the indoor air quality and prevalence of asthma, allergies and respiratory symptoms of attending children. The higher prevalence rates of allergic and respiratory symptoms among young children, whose immune system is still under-developed, in child care centers, whether fully or partially air-conditioned, suggest that ventilation and plausible growth and propagation mechanisms of allergens and infectious agents be further investigated.

Oyster-associated outbreaks of Norovirus gastroenteritis in Singapore.

Outbreaks of gastroenteritis associated with the consumption of raw imported half-shelled frozen oysters occurred in Singapore between 16 Dec 2003 and 04 Jan 2004. A total of 305 cases were reported with clinical symptoms of diarrhoea (94%), abdominal cramps (72%), vomiting (69%) and fever (54%). The median incubation period was 30.8h and the duration of illness was 2-3 days. The overall relative risk of oyster consumption was 14.1 (95% CI: 8.3-24.0, P<0.001). Stool and oyster samples tested negative for common bacterial pathogens, including Vibrio parahaemolyticus. However, stool samples were positive for the presence of Norovirus group II RNA via RT PCR while oyster samples indicated the presence of Norovirus particles by electron microscopy. The clinical and epidemiological features were suggestive of Norovirus gastroenteritis and were subsequently confirmed by laboratory tests of stools and implicated oysters. Steps have been taken to ensure that food outlets do not thaw frozen oysters and serve them raw.