No abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically important swine pathogens because it is highly infectious and causes economic losses due to decreased pig productivity. In this study, the 603 bp complete major envelope protein encoding gene (ORF5) of 32 field PRRSV isolates from Vietnam collected during 2008-2012 were sequenced and analyzed. Multiple nucleotide (nt) and deduced amino acid (aa) alignments of ORF5 were performed on the 32 isolates: the representative strains (European and North American genotypes), Chinese strains available in GenBank and vaccine strains licensed for use in Vietnam. The results showed 94.8-100.0% nt identity and 94.0-100% aa similarity among the 32 isolates. These isolates shared similarities with the prototype of the North American PRRSV strain (VR-2332; nt 87.8-89.3%, aa 87.5-90.0%), and Lelystat virus, the prototype of the European PRRSV strain (LV; nt 61.1-61.9%, aa 55.1-57.0%). There was greater similarity with QN07 (nt 96.5-98.5%, aa 96.0-99.0%) from the 2007 PRRS outbreak in QuangNam Province, CH-1a (nt 93.2-95.1%, 91.5-93.5%) isolated in China in 1995 and JXA1 (nt 96.5-98.6%, aa 95.0-98.0%), the highly pathogenic strain from China isolated in 2006. The Vietnamese isolates were more similar to JXA1-R (nt 96.5-98.6%, aa 95.0-98.0%), the strain used in Chinese vaccines, than to Ingelvac MLV/BSL-PS (nt 87.2-89.0%, aa 86.0-89.0%). Phylogenetic analysis showed that the 32 isolates were of the North American genotype and classified into sub-lineage 8.7. This sub-lineage contains highly pathogenic Chinese PRRSV strains. This study documents genetic variation in circulating PRRSV strains and could assist more effective use of PRRS vaccines in Vietnam.

Microplastics threaten the ecosystem because of undesirable properties such as non-biodegradability, easy-to-absorb persistant organic compounds, etc. They are found worldwide in marine, fresh water and beach sand environments. In this study, microplastics in beach sand samples from two sites in Tien Giang province and two sites in Vung Tau city were investigated. The results showed that the microplastics amount was 0 to 295 pieces/kg dry sand and they mainly distributed near estuarine areas. Microplastics were more prevalent at bathing sites than non-bathing sites. In Tien Giang fragments were the most dominant among the three types of shapes (fragments, fibers, granules) at 60.2%. In Vung Tau granules were most prevalent at 71.7%. The composition of the plastics was confirmed by Fourier-transform infrared spectroscopy. It was revealed that PE, PP and PS were the main types of plastics found in the sampling sites.

Microplastics pollution in Vietnam has received significant attention in recent years because of its adverse effects on the environment. This study examined the abundance, physical characteristics, and chemical composition of microplastics in beach sand from the Can Gio Coast, Ho Chi Minh City, Vietnam for the first time. Five beaches with different features and anthropogenic activities along the Can Gio Coast were selected. Ninety sand samples were collected from the edge of the water to the upper shoreline at different depths to assess the spatial distribution of microplastics. Microplastics were extracted by density separation in a solution of sodium chloride (NaCl) and zinc chloride (ZnCl2) and examined by attenuated total reflection-Fourier transform infrared spectroscopy (FTIR-ATR). The abundance of microplastics varied from 0 to 6.58 pieces/kg d.w. Microplastics were detected mostly along the upper shoreline and in the surface sand layer. The dimension of the microplastics ranged from 2.8 to 5 mm (71.4%), granules accounted for the highest proportion of shape (42.9%), and white and blue were the two most prevalent colors (81%). Polypropylene, polystyrene, and polyethylene were the three most common polymer types. The characteristics of microplastics indicate that their origin may be from resin pellets, tourism activities, and aquacultural activities.