Synergistic infection of Edwardsiella ictaluri and Flavobacterium oreochromis in cage cultured tilapia (Oreochromis sp.).

Widespread distribution of a highly pathogenic Edwardsiella ictaluri strain in farmed tilapia in northern Vietnam has recently been reported. The subsequent investigation noticed a disease outbreak occurred at five nearby tilapia farms with floating cages, in which the clinical signs of both edwardsiellosis and columnaris diseases were observed on the same infected fish and caused 65% to 85% fish mortality. Naturally diseased fish (n = 109) were sampled from the five infected farms for bacterial identification and conducting challenge tests. The two bacteria Edwardsiella ictaluri and Flavobacterium oreochromis were identified by a combination of biochemical tests, PCR and 16SrRNA sequencing methods. Experimental challenge tests on Nile tilapia resulted in the median lethal dose (LD50 ) of E. ictaluri and F. oreochromis at 70 CFU/fish by intraperitoneal (i.p.) injection and 3.6 × 106 CFU/mL by immersion, respectively. The experimentally co-infected challenged fish exposed to LD50 doses resulted in 83% ± 6% mortality, with the infected fish exhibiting clinical signs of both edwardsiellosis and columnaris diseases, mimicking the naturally diseased fish. This finding suggests that the co-infection of E. ictaluri and F. oreochromis may interact in a synergistic manner, to enhance the overall severity of the infection and elevates the need for efficient methods to control both pathogens.

First confirmed case of infant botulism caused by Clostridium botulinum type A(B) in a 10-month-old infant in Hanoi, Vietnam.

Infant botulism is a rare but sometimes life-threatening toxemia caused by ingestion of Clostridium botulinum spores. Although cases of infant botulism have probably occurred in Vietnam in the past, they have never been diagnosed and reported. Herein, we report the isolation of C. botulinum type A(B) from the stool of a 10-month-old infant during hospitalization.

Widespread presence of a highly virulent Edwardsiella ictaluri strain in farmed tilapia, Oreochromis spp.

Edwardsiella ictaluri is an emerging bacterial pathogen that affects farmed tilapia (Oreochromis spp.). This study reports the widespread presence of E. ictaluri in farmed tilapia in Vietnam. Among 26 disease outbreaks from nine provinces in Northern Vietnam during 2019-2021, 19 outbreaks originated from imported seeds, while outbreaks in seven farms were from domestic sources. Clinically sick fish showed the appearance of numerous white spots in visceral organs, and accumulative mortality reached 30%-65%. A total of 26 representative bacterial isolates recovered from 26 disease outbreaks were identified as E. ictaluri based on a combination of phenotypic tests, genus- and species-specific polymerase chain reaction assays, 16S rRNA and gyrB sequencing, and phylogenetic analysis. All isolates harboured the same virulence gene profiles esrC+ , evpC+ , ureA-C+ , eseI- , escD- and virD4- . Antimicrobial susceptibility tests revealed that 80.8%-100% of isolates were multidrug resistant, with resistance to 4-8 antimicrobials in the groups of penicillin, macrolides, sulfonamides, amphenicols and glycopeptides. The experimental challenge successfully induced disease that mimicked natural infection. The median lethal doses (LD50 ) of the tested isolates (n = 4) were 42-61 colony forming units/fish, indicating their extremely high virulence. This emerging pathogen is established and has spread to various geographical locations, causing serious impacts on farmed tilapia in northern Vietnam. It is likely that this pathogen will continue to spread through contaminated stocks (both imported and domestic sources) and persist. Thus, increased awareness, combined with biosecurity measures and emergent vaccination programs is essential to mitigate the negative impact of this emerging disease on the tilapia farming industry.

Detection and characterization of Kudoa thunni from uncooked yellowfin tuna (Thunnus albacares) in Southeast Asia.

Myxosporean parasites Kudoa spp. have been reported in several marine fish species worldwide. However, little is known about the contamination of these parasites in raw fish in Southeast Asia, where the consumption demand of uncooked fish is increasing. In 2019, the occurrence of several cases of raw yellowfin tuna (Thunnus albacares) obtained from retail shops with the presence of unknown white, nodular cysts within the musculature have raised public health concerns for the consumption of raw marine fish in Vietnam. Microscopic examination revealed numerous myxospores with the quadratic shape of the Kudoidae. Morphologically, stained spores detected in this study are suspected to Kudoa thunni. To confirm the suspected Kudoa species, further examination of the 18S small-subunit (SSU) was conducted and the results of nucleotide sequence analysis obtained from nodular cysts revealed 99.18-100% identity to that of Kudoa thunni sequences available in GenBank. Detection of K. thunni infection in tuna in Southeast Asia highlights the need for appropriate surveillance and control measures to ensure high quality standards and safety on raw fish production and consumption.

Early screening and diagnosis of autism spectrum disorders in Vietnam: A population-based cross-sectional survey.

BACKGROUND: Early detection of autism spectrum disorders (ASDs) is essential given the under-reported cases in low- and middle-income countries. This first national representative survey was conducted to explore the prevalence of ASDs amongst 18 and 30 months in seven provinces in Vietnam. DESIGN AND METHODS: During 2017- 2018, a national cross-sectional and population-based survey for autism spectrum disorder (ASD) amongst 40,243 children aged 18 to 30 months was conducted in 7 provinces representing the socio-economic regions of Vietnam. M-CHAT was used to screen children and then confirmed by diagnostic assessment using DSM-IV criteria. RESULTS: The prevalence of ASDs amongst children aged 18 and 30 months in Vietnam was high (0.758% or 1 in 132 children). Urban setting, male gender, and hereditable genes were associated with ASD prevalence. CONCLUSIONS: ASDs amongst children aged 18 and 30 months in Vietnam tend to be increasing and are similar to this rate in other middle-income countries but lower than that in Western countries. This under-recognized public health problem amongst children should be addressed by early detection and intervention for families with affected children.

Nutritional Status of Children with Cerebral Palsy-Findings from Prospective Hospital-Based Surveillance in Vietnam Indicate a Need for Action.

BACKGROUND: Lack of evidence on the burden and risk factors for malnutrition among children with cerebral palsy (CP) in Vietnam limits evidence-based interventions. We aimed to define the nutritional status of children with CP in Vietnam. MATERIALS AND METHODS: The study utilized data from active prospective hospital-based surveillance modelled on the Pediatric Active Enhanced Disease Surveillance system. Children (0-18 years) with CP attending the National Children's Hospital Hanoi, Vietnam between June-November 2017 were included. Data on demographic, clinical and rehabilitation status were collected following detailed neurodevelopmental assessment. Anthropometric measurements were taken. Nutritional status was determined using the World Health Organization guideline. RESULTS: Of 765 children (the mean (SD) age was 2.6 (2.5) years; 35.8% were female), 28.9% (n = 213) were underweight and 29.0% (n = 214) stunted. The odds of underweight were significantly higher among children aged >5 years and/or having a monthly family income of <50 USD. Underweight and/or stunting was high among children with quadriplegia (81%, n = 60 and 84.5%, n = 87) and/or Gross Motor Functional Classification System (GMFCS) level IV-V (62.5%, n = 45 and 67.0%, n = 67). Nearly one-third of intellectually impaired and more than half of hearing-impaired children were underweight and/or stunted. CONCLUSIONS: Poor economic status and increased motor severity increased vulnerability to malnutrition. Our findings will inform nutritional rehabilitation programs among these vulnerable children.

Protocol for hospital based-surveillance of cerebral palsy (CP) in Hanoi using the Paediatric Active Enhanced Disease Surveillance mechanism (PAEDS-Vietnam): a study towards developing hospital-based disease surveillance in Vietnam.

INTRODUCTION: The epidemiology, pathogenesis, management and outcomes of cerebral palsy (CP) in low-income and middle-income countries including Vietnam are unknown because of the lack of mechanisms for standardised collection of data. In this paper, we outline the protocol for developing a hospital-based surveillance system modelled on the Paediatric Active Enhanced Disease Surveillance (PAEDS) system in Australia. Using PAEDS-Vietnam we will define the aetiology, motor function and its severity, associated impairments, and nutritional and rehabilitation status of children with CP in Hanoi, Vietnam. These essential baseline data will inform future health service planning, health professional education and training, and family support. METHODS AND ANALYSIS: This is a hospital-based prospective surveillance of children with CP presenting to the rehabilitation, neurology and general paediatric services at the National Children's Hospital and St Paul Hospital in Hanoi. We will use active, prospective daily case-finding for all children with CP aged <18 years who are hospitalised or present to outpatient departments. Following parental consent, data will be collected using a modified version of the Australian Cerebral Palsy Register questionnaire. The data collection form has been developed in consultation with local and international experts and translated into Vietnamese. Information collected will include demographics, maternal health and birth history, type and severity of CP, known risk factors for CP, and nutrition, immunisation, education and rehabilitation status. ETHICS AND DISSEMINATION: This study was approved by the Hanoi Medical University Institutional Review Board (decision no 1722) and The University of Sydney Human Research Ethics Committee (approval no 2016/456). Establishment of PAEDS-Vietnam will enable hospital-based surveillance of CP for the first time in Vietnam. It will identify preventable causes of CP, patient needs and service gaps, and facilitate early diagnosis and intervention. Study findings will be disseminated through local and international conferences and peer-reviewed publications.

Protective Effects of 2-Dodecyl-6-Methoxycyclohexa-2,5 -Diene-1,4-Dione Isolated from Averrhoa Carambola L. (Oxalidaceae) Roots on High-Fat Diet-Induced Obesity and Insulin Resistance in Mice.

BACKGROUND/AIMS: The roots of Averrhoa carambola L. (Oxalidaceae) have long been used as a traditional Chinese medicine for the treatment of diabetes and diabetes-related diseases. 2-dodecyl-6-methoxycycyclohexa-2,5-1,4-dione (DMDD) has been isolated from A. carambola L. roots, and this study was carried out to investigate the potential beneficial effects of DMDD on obesity and insulin resistance induced by a high-fat diet (HFD) in mice. METHODS: C57BL/6J mice were fed a HFD for 16 weeks and orally administered DMDD (12.5, 25, or 50 mg/kg of body weight per day) and metformin (280 mg/kg of body weight per day) for the last 4 weeks. RESULTS: The body weights and adipose tissue weights as well as the serum levels of blood glucose, total cholesterol, triglycerides, free fatty acids, insulin, interleukin-6, and tumor necrosis factor-α were significantly decreased by DMDD, and the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor (Myd88) in the epididymal adipose tissue was downregulated by DMDD. In contrast, insulin sensitivity was enhanced. The results of the glucose tolerance tests, insulin tolerance tests, and insulin release tests indicated that there was a marked improvement in insulin secretion, and the areas under the curve corresponding to the three tests were also significantly decreased by DMDD. The activities of superoxide dismutase and glutathione peroxidase were simultaneously enhanced, whereas the content of malondialdehyde was decreased by DMDD in the liver homogenates of the C57BL/6J mice. In addition, hepatic steatosis and adipocyte hypertrophy, as assessed by H&E staining of liver and adipose tissues, were significantly improved by DMDD. CONCLUSION: These data suggest that MDD has potential benefits for the treatment of HFD-induced obesity and insulin resistance, and its effects may be associated with improvements in lipid metabolism and inhibition of the expression of TLR4 in adipose tissues.

Severe malaria not responsive to artemisinin derivatives in man returning from Angola to Vietnam.

Resistance to artemisinin derivatives, the most potent antimalarial drugs currently used, has emerged in Southeast Asia and threatens to spread to Africa. We report a case of malaria in a man who returned to Vietnam after 3 years in Angola that did not respond to intravenous artesunate and clindamycin or an oral artemisinin-based combination.

Detection of porcine reproductive and respiratory syndrome virus in oral fluid from naturally infected pigs in a breeding herd.

The objectives of the present study were to evaluate the anatomic localization of porcine reproductive and respiratory syndrome virus (PRRSV) in naturally infected pigs and to determine whether oral fluid could be used to detect the virus in infected animals. Two sows, seven 2-month-old grower pigs, and 70 6-month-old gilts were included in this study. PRRSV in sera and oral fluid were identified by nested reverse transcription PCR (nRT-PCR) while lung, tonsil, and tissue associated with oral cavity were subjected to nRT-PCR, immunohistochemistry, and in situ hybridization. In sows, PRRSV was identified in oral fluid and tonsils. PRRSV was also detected in oral fluid, tonsils, salivary glands, oral mucosa, and lungs of all seven grower pigs. However, viremia was observed in only two grower pigs. Double staining revealed that PRRSV was distributed in macrophages within and adjacent to the tonsillar crypt epithelium. In gilts, the North American type PRRSV field strain was detected 3 to 8 weeks after introducing these animals onto the farm. These results confirm previous findings that PRRSV primarily replicates in tonsils and is then shed into oral fluid. Therefore, oral fluid sampling may be effective for the surveillance of PRRSV in breeding herds.