NSP2 gene variation of the North American genotype of the Thai PRRSV in central Thailand

Porcine reproductive and respiratory syndrome virus (PRRSV) is a major swine pathogen causing economic losses in the swine industry almost worldwide. PRRSV has been divided into 2 genotypes, the European (Type 1) and North American (Type 2) genotype, respectively and displays a large degree of genetic variability, particularly at the nonstructural protein (nsp) 2 gene. This is the first study determining genetic variation of the nsp2 of Thai PRRSV isolates. The results showed that 9 out of 10 Thai PRRSV isolates were nsp2-truncated viruses that might have evolved from a virus previously introduced in the past, but not from one recently introduced

Genetic characterization of avian influenza subtype H4N6 and H4N9 from live bird market, Thailand

A one year active surveillance program for influenza A viruses among avian species in a live-bird market (LBM) in Bangkok, Thailand was conducted in 2009. Out of 970 samples collected, influenza A virus subtypes H4N6 (n = 2) and H4N9 (n = 1) were isolated from healthy Muscovy ducks. All three viruses were characterized by whole genome sequencing with subsequent phylogenetic analysis and genetic comparison. Phylogenetic analysis of all eight viral genes showed that the viruses clustered in the Eurasian lineage of influenza A viruses. Genetic analysis showed that H4N6 and H4N9 viruses display low pathogenic avian influenza characteristics. The HA cleavage site and receptor binding sites were conserved and resembled to LPAI viruses. This study is the first to report isolation of H4N6 and H4N9 viruses from birds in LBM in Thailand and shows the genetic diversity of the viruses circulating in the LBM. In addition, co-infection of H4N6 and H4N9 in the same Muscovy duck was observed

Comparative analysis of complete nucleotide sequence of porcine reproductive and respiratory syndrome virus (PRRSV) isolates in Thailand (US and EU genotypes)

<p>Abstract</p> <p>Background</p> <p>Porcine reproductive and respiratory syndrome virus (PRRSV) is a causative agent of Porcine Reproductive and Respiratory Syndrome (PRRS). In this study, the complete nucleotide sequences of the selected two Thai PRRSV isolates, EU (01CB1) and US (01NP1) genotypes were determined since both isolates are the Thai prototypes.</p> <p>Results</p> <p>01CB1 and 01NP1 contain 14,943 and 15,412 nucleotides, respectively. The viruses compose 2 untranslated regions (5' UTR and 3' UTR) and 8 open reading frames (ORFs) designated as ORF1a, ORF1b and ORF2-7. Phylogenetic analysis of full length of the viruses also showed that the 01CB1 and 01NP1 were grouped into the EU and US genotype, respectively. In order to determine the genetic variation and genetic relatedness among PRRSV isolates, the complete nucleotide sequences of PRRSV isolated in Thailand, 01CB1 and 01NP1 were compared with those of 2 EU strains (Lelystad, and EuroPRRSV), 6 US strains (MLV, VR2332, PA8, 16244B, SP and HUN4). Our results showed that the 01CB1 genome shares approximately 99.2% (Lelystad) and 95.2% (EuroPRRSV) nucleotide identity with EU field strains. While, the 01NP1 genome has 99.9% nucleotide identity with a live vaccine strain (MLV) and 99.5% and 98.5% nucleotide identity with 2 other US isolates, VR2332 and 16244B, respectively. In addition, ORF5 nucleotide sequences of 9 PRRS viruses recovered in Thailand during 2002-2008 were also included in this study. Phylogenetic analysis of ORF5 showed high similarity among EU and US genotypes of the recent Thai PRRS viruses (2007-2008 viruses) with 01CB1 and 01NP1.</p> <p>Conclusion</p> <p>Overall, the results suggested that the Thai EU isolate (01CB1) may evolve from the EU prototype, Lelystad virus, whereas the Thai US isolate (01NP1) may originate and evolve from the vaccine virus or its derivatives. Interestingly, the US-MLV vaccine was not available in the Thai market in 2001. The Vaccine-like virus might have persisted in the imported pigs or semen and later spread in the Thai swine industry. This report is the first report of complete nucleotide sequences of the Thai PRRS viruses both EU and US genotypes.</p

Genetic diversity and multiple introductions of porcine reproductive and respiratory syndrome viruses in Thailand

Porcine reproductive and respiratory syndrome virus (PRRSV) is prevalent in Thailand, causing a huge impact on the country's swine industry. Yet the diversity and origin of these Thai PRRSVs remained vague. In this context, we collected all the Thai PRRSV sequences described earlier and incorporated them into the global diversity. The results indicated that PRRSVs in Thailand were originated from multiple introductions involving both Type 1 and Type 2 PRRSVs. Many of the introductions were followed by extensive geographic expansion, causing regional co-circulation of diverse PRRSV variants in three major pig-producing provinces. Based on these results, we suggest (1) to avoid blind vaccination and to apply vaccines tailor-made for target diversity, (2) to monitor pig importation and transportation, and (3) to implement a better biosecurity to reduce horizontal transmissions as three potentially effective strategies of controlling PRRS in Thailand

Influenza Virus (H5N1) in Live Bird Markets and Food Markets, Thailand

A surveillance program for influenza A viruses (H5N1) was conducted in live bird and food markets in central Thailand during July 2006–August 2007. Twelve subtype H5N1 viruses were isolated. The subtype H5N1 viruses circulating in the markets were genetically related to those that circulated in Thailand during 2004–2005

Comparative analysis of Mycobacterium avium subsp. paratuberculosis isolates from cattle, sheep and goats by short sequence repeat and pulsed-field gel electrophoresis typing

<p>Abstract</p> <p>Background</p> <p><it>Mycobacterium avium </it>subsp. <it>paratuberculosis </it>(Map) causes the chronic enteritis called paratuberculosis mainly in cattle, sheep and goats. Evidences that point out an association between Map and Crohn's Disease in humans are increasing. Strain differentiation among Map isolates has proved to be difficult and has limited the study of the molecular epidemiology of paratuberculosis. In order to asses the usefulness of the PCR based short sequence repeat (SSR) analysis of locus 1 and locus 8 in the epidemiological tracing of paratuberculosis strains we here compare for the first time the results of SSR and <it>Sna</it>BI-<it>Spe</it>I pulsed-field gel electrophoresis (PFGE) typing methods in a set of 268 Map isolates from different hosts (cattle, sheep, goats, bison, deer and wild boar).</p> <p>Results</p> <p>A total of nineteen different multi-locus SSR (SSR1_SSR8) types were identified amongst the 268 isolates compared to the 37 multiplex profiles differentiated by the <it>Sna</it>BI-<it>Spe</it>I PFGE. SSR type 7_4 was the predominant genotype (51.2% of all isolates and 54.3% of cattle isolates), but combined with PFGE results the abundance of the most prevalent genotype (7_4&{2-1}) dropped down to 37.7%. SSR types 7_3 and 14_3 were significantly spread amongst isolates recovered from small ruminants. The comparison of SSR1_SSR8 and <it>Sna</it>BI-<it>Spe</it>I PFGE typing of these isolates has shown that both methods perform at similar discriminatory level. These were 0.691 and 0.693, respectively for SSR and PFGE as indicated Simpson's Index of Diversity, and 0.82 when calculated for combined SSR and PFGE genotypes. Overall, SSR1_SSR8 analysis seemed to detect higher levels of within-farm strain diversity and seemed to give higher year-related information. Combination of both typing methods revealed 20 multi-type farms out of the 33 bovine farms studied with more than one isolate.</p> <p>Conclusion</p> <p>The particular SSR and PFGE typing approaches described here are in general agreement but they showed some discrepancies that might reflect differing evolutionary processes of Map strains. Both methods are able to reciprocally complement their results and neither should be replaced with the other if sufficient material and time is available. Overall, the results of our comparative analyses suggest that, based on current methodologies available, a combined approach that includes SSR and PFGE seems to provide the highest level of discrimination for Map strain typing with meaningful epidemiological information.</p

Genetic variations of nucleoprotein gene of influenza A viruses isolated from swine in Thailand

<p>Abstract</p> <p>Background</p> <p>Influenza A virus causes severe disease in both humans and animals and thus, has a considerably impact on economy and public health. In this study, the genetic variations of the nucleoprotein (NP) gene of influenza viruses recovered from swine in Thailand were determined.</p> <p>Results</p> <p>Twelve influenza A virus specimens were isolated from Thai swine. All samples were subjected to nucleotide sequencing of the complete NP gene. Phylogenetic analysis was conducted by comparing the NP gene of swine influenza viruses with that of seasonal and pandemic human viruses and highly pathogenic avian viruses from Thailand (n = 77). Phylogenetic analysis showed that the NP gene from different host species clustered in distinct host specific lineages. The NP gene of swine influenza viruses clustered in either Eurasian swine or Classical swine lineages. Genetic analysis of the NP gene suggested that swine influenza viruses circulating in Thailand display 4 amino acids unique to Eurasian and Classical swine lineages. In addition, the result showed 1 and 5 amino acids unique to avian and human lineages, respectively. Furthermore, nucleotide substitution rates showed that the NP gene is highly conserved especially in avian influenza viruses.</p> <p>Conclusion</p> <p>The NP gene sequence of influenza A in Thailand is highly conserved within host-specific lineages and shows amino acids potentially unique to distinct NP lineages. This information can be used to investigate potential interspecies transmission of influenza A viruses. In addition, the genetic variations of the NP gene will be useful for monitoring the viruses and preparing effective prevention and control strategies for potentially pandemic influenza outbreaks.</p

Avian Influenza H5N1 in Naturally Infected Domestic Cat

We report H5N1 virus infection in a domestic cat infected by eating a pigeon carcass. The virus isolated from the pigeon and the cat showed the same cluster as the viruses obtained during the outbreak in Thailand. Since cats are common house pets, concern regarding disease transmission to humans exists