A long-term observation for ecology of pathogenic Yersinia in wild rodents living in Fukushima Prefecture, Japan.

From 2012 to 2021, prevalence of pathogenic Yersinia in wild rodents captured in Fukushima Prefecture, Japan was investigated twice a year to clarify the ecology of this pathogen in wild rodent populations. Pathogenic Yersinia enterocolitica O8 was isolated from 13 (1.7%) of 755 wild rodents. The Y. enterocolitica O8 isolates harbored three virulent genes (ail, fyuA, and virF). This pathogen was isolated repeatedly from wild rodents in April 2015, 2016, and 2017, in June and November 2020, and in April 2021, which was 6 of 19 times of observations. All Y. enterocolitica O8 isolates showed the same PFGE patterns. These results indicated that the same clone of pathogenic Y. enterocolitica O8 has been maintained in wild rodent populations in Fukushima Prefecture. Therefore, wild rodent populations contribute substantially to the continuous transmission of Y. enterocolitica O8 and its persistence in the ecosystem. This is the first report on the isolation of pathogenic Y. enterocolitica O8 in wild rodents in Fukushima Prefecture, Japan.

Effects of Feed Mixed with Lactic Acid Bacteria and Carbon, Nitrogen, Phosphorus Supplied to the Water on the Growth and Survival Rate of White Leg Shrimp (Penaeus vannamei) Infected with Acute Hepatopancreatic Necrosis Disease Caused by Vibrio parahaemolyticus.

This study aimed to evaluate the growth, survival rate, and resistance to acute hepatopancreatic necrosis disease (AHPND) of white leg shrimp (Penaeus vannamei) by using Lactobacillus plantarum, Lactobacillus fermentum, and Pediococcus pentosaceus mixed with feed, and at the same time supplying CNP in a ratio of 15:1:0.1 to the water. As a result, the treatments that shrimp were fed with feed containing lactic acid bacteria (LAB), especially L. plantarum, have increased shrimp growth, total hemocyte cells, granulocyte cells, and hyaline cells significantly (p < 0.05) in comparison to the control group. The supply of CNP to the water has promoted the intensity of V. parahaemolyticus effects on shrimp health and significantly decreased total hemocyte cells, granulocyte cells, and hyaline cells by 30-50% in the period after three days of the challenge, except in L. plantarum treatment, which had only a 20% decrease compared to other treatments. In CNP supplying treatments, the AHPND infected rate and mortality of shrimp were higher than those in other treatments. In summary, the supply of CNP had significantly reduced the shrimp's immune response and promoted the susceptibility of shrimp to AHPND in both cases of use with and without LAB-containing diets.

Prevalence of Vibrio parahaemolyticus Causing Acute Hepatopancreatic Necrosis Disease of Shrimp in Shrimp, Molluscan Shellfish and Water Samples in the Mekong Delta, Vietnam.

A total of 481 samples, including 417 shrimp and molluscan shellfish samples from retail shops and farms and 64 water samples from shrimp and molluscan shellfish farms in the Mekong Delta located the southern part of Vietnam, were examined for the presence of Vibrio parahaemolyticus (VpAHPND) caused acute haepatopancreatic necrosic disease (AHPND) in shrimp. VpAHPND strains were isolated in two of 298 (0.7%) molluscan shellfish samples from retail shops, seven of 71 (9.9%) shrimp samples from shrimp ponds, and two of 42 (4.8%) water samples from shrimp ponds. VpAHPND strains were classified into two types of O antigen, including O1 and O3, in which O1 was the predominant. VpAHPND strains isolated showed high resistance rates to colistin (100%), ampicillin (93.8%), and streptomycin (87.5%). These results indicate that VpAHPND is widely prevalent in environment in the Mekong Delta, Vietnam.

Native drivers of fish life history traits are lost during the invasion process.

Rapid adaptation to global change can counter vulnerability of species to population declines and extinction. Theoretically, under such circumstances both genetic variation and phenotypic plasticity can maintain population fitness, but empirical support for this is currently limited. Here, we aim to characterize the role of environmental and genetic diversity, and their prior evolutionary history (via haplogroup profiles) in shaping patterns of life history traits during biological invasion. Data were derived from both genetic and life history traits including a morphological analysis of 29 native and invasive populations of topmouth gudgeon Pseudorasbora parva coupled with climatic variables from each location. General additive models were constructed to explain distribution of somatic growth rate (SGR) data across native and invasive ranges, with model selection performed using Akaike's information criteria. Genetic and environmental drivers that structured the life history of populations in their native range were less influential in their invasive populations. For some vertebrates at least, fitness-related trait shifts do not seem to be dependent on the level of genetic diversity or haplogroup makeup of the initial introduced propagule, nor of the availability of local environmental conditions being similar to those experienced in their native range. As long as local conditions are not beyond the species physiological threshold, its local establishment and invasive potential are likely to be determined by local drivers, such as density-dependent effects linked to resource availability or to local biotic resistance.

Selection of Lactic Acid Bacteria (LAB) Antagonizing Vibrio Parahaemolyticus: The Pathogen of Acute Hepatopancreatic Necrosis Disease (AHPND) in Whiteleg Shrimp (Penaeus Vannamei).

Acute hepatopancreatic necrosis disease (AHPND) has recently emerged as a serious disease of cultured shrimp. A total of 19 lactic acid bacteria (LAB) strains isolated from shrimp samples were characterized based on morphological characteristics, biochemical tests, sequencing analysis, and their ability to antagonize Vibrio parahaemolyticus, which causes AHPND in whiteleg shrimp. Results from the agar well diffusion method indicated that 3 out of 19 isolated LAB strains showed the highest antagonizing ability against AHPND V. parahaemolyticus strain with an inhibition zone diameter ranging from 18 to 20 mm. Experiments where shrimps were given feed supplemented with these LAB strains and challenged with AHPND strain showed high survival rates (approximately 80.0%), which were not significantly different as compared to those recorded in the negative control treatment (86.6%), but significantly different to those recorded in the positive control treatment (40.6%) after 16 days of the experiment. However, the histological images of shrimp hepatopancreas indicated that the infection rate significantly reduced from 60.0% to 11.1% in shrimps fed with LAB-supplemented feeds and challenged with AHPND V. parahaemolyticus strain as compared to those in the positive control treatment. A polymerase chain reaction (PCR) and 16S rRNA gene sequencing confirmed the identification of LAB strain. These results can be applied in further experiments to investigate the ability of L. plantarum in preventing AHPND in intensively cultured whiteleg shrimp.

Prevalence of Vibrio parahaemolyticus in seafood and water environment in the Mekong Delta, Vietnam.

A total of 449 samples including 385 seafood and 64 water samples in the Mekong Delta of Vietnam collected in 2015 and 2016 were examined. Of 385 seafood samples, 332 (86.2%) samples were contaminated with Vibrio parahaemolyticus and 25 (6.5%) samples were pathogenic V. parahaemolyticus carrying tdh and/or trh genes. The tdh gene positive V. parahaemolyticus strains were detected in 22 (5.7%) samples and trh gene positive V. parahaemolyticus strains were found in 5 (1.3%) samples. Of 25 pathogenic V. parahaemolyticus strains, two strains harbored both tdh and trh genes and the other 23 strains carried either tdh or trh gene. Of 64 water samples at aquaculture farms, 50 (78.1%) samples were contaminated with V. parahaemolyticus. No tdh gene positive V. parahaemolyticus strains were detected; meanwhile, trh gene positive V. parahaemolyticus strain was detected in 1 (1.6%) sample. Twenty-six pathogenic V. parahaemolyticus strains isolated were classified into 6 types of O antigen, in which the serotype O3:K6 was detected in 4 strains. All pathogenic strains were group-specific PCR negative except for 4 O3:K6 strains. The result of antimicrobial susceptibility test indicated that pathogenic strains showed high resistance rates to streptomycin (84.6%), ampicillin (57.7%) and sulfisoxazole (57.7%). These findings can be used for understanding microbiological risk of seafood in the Mekong Delta, Vietnam.

The importance of wild gecko as a source of human Salmonella infection.

A total of 201 wild geckos from the region of Mekong Delta, Vietnam were collected to determine the viable number and survival period of Salmonella in their feces. Of the 101 samples examined, 24 (23.8%) were Salmonella positive. These 24 geckos excreted Salmonella in their feces in a range of 1 to 8.6 log CFU/g with a mean of 4.5 ± 3.2 log CFU/g. Among the Salmonella serovars, Salmonella Weltevreden was the most predominant serovar (37.5%). Moreover, Salmonella could survive for 6 weeks in gecko feces at room temperature in Vietnam. These results indicate that the wild gecko seems to play an important role as a reservoir for Salmonella and a source of Salmonella infection in humans in Southeast Asian countries.

Safety and efficacy of thrombin-JMI: a multidisciplinary expert group consensus.

BACKGROUND: The use of bovine thrombin has been an effective approach to aiding hemostasis during surgery for over 60 years. Its use has a reported association with the development of antibodies to coagulation factors with limited evidence to the clinical significance. METHODS: The Collaborative Delphi survey methodology was used to develop a consensus on specified topic areas from a panel of 12 surgeons/scientists who have had experience with topical thrombins; it consisted of 2 rounds of a Web-based survey and a final live discussion. RESULTS: Some key issues that reached consensus included: bovine, human plasma-derived and recombinant human thrombin are equally effective hemostatic agents with similar adverse event rates, and immunogenicity to a topical protein rarely translate into adverse events. CONCLUSIONS: Although a risk of immunogenicity is associated with all topical thrombins, no conclusive clinical evidence is available that these antibodies have any significant effect on short- and long-term clinical consequences.

Chemical quality of purified tetanus antitoxin and anti-rabies serum produced at the Institute of Vaccine (IVAC), from 1997-2001

59 batches of purified tetanus antitoxin and 20 batches of anti-rabies serum (1997-2001) produced at IVAC Nha Trang were tested for: pH, total nitrogen, merthiolate content, sodium chloride content. In general, all the batches met the minimum requirements of the manufacture. However in order to improve the quality of the sera additional requirements should be set up