Outbreak In Thailand Research Articles

Genetic diversity of ORF3 and spike genes of porcine epidemic diarrhea virus in Thailand

Porcine epidemic diarrhea virus (PEDV) has become endemic in the Thai swine industry, causing economic losses and repeated outbreaks since its first emergence in 2007. In the present study, 69 Thai PEDV isolates were obtained from 50 swine herds across Thailand during the period 2008–2012. Both partial and complete nucleotide sequences of the spike (S) glycoprotein and the nucleotide sequences of ORF3 genes were determined to investigate the genetic diversity and molecular epidemiology of Thai PEDV. Based on the analysis of the partial S glycoprotein genes, the Thai PEDV isolates were clustered into 2 groups related to Korean and Chinese field isolates. The results for the complete spike genes, however, demonstrated that both groups were grouped in the same cluster. Interestingly, both groups of Thai PEDV isolates had a 4-aa (GENQ) insertion between positions 55 and 56, a 1-aa insertion between positions 135 and 136, and a 2-aa deletion between positions 155 and 156, making them identical to the Korean KNU series and isolates responsible for outbreaks in China in recent years. In addition to the complete S sequences, the ORF3 gene analyses suggested that the isolates responsible for outbreaks in Thailand are not vaccine related. The results of this study suggest that the PEDV isolates responsible for outbreaks in Thailand since its emergence represent a variant of PEDV that was previously reported in China and Korea.

Changes in the NS1 gene of avian influenza viruses isolated in Thailand affect expression of type I interferon in primary chicken embryonic fibroblast cells

The non-structural protein 1 (NS1) of avian influenza virus was defined as one of the virulent factors. To understand the effect of NS1 protein of influenza virus H5N1 isolated in Thailand on type I (α/β) interferon (IFN) synthesis, five reverse genetic viruses were constructed and used as models. The viruses were generated using NS genomic segment from A/Peurto Rico/8/1934 (H1N1) and four avian influenza viruses isolated from the first outbreak in Thailand. All the viruses have the rest of the genome from A/Peurto Rico/8/1934 (H1N1). The constructed viruses were named (1) NS1 PR8/34, (2) NS1 wild type, (3) NS1 L15FD53G, (4) NS1 N171I and (5) NS1 E71K, respectively. The type I (α/β) IFN gene expression in control and infected primary chicken embryonic fibroblast cells were analyzed by quantitative polymerase chain reaction. The results show that the inhibition of IFN-β gene expression by NS1 wild type infected cells is stronger than NS1 N171I, NS1 E71K, NS1 PR8/34 and NS1 L15FD53G, respectively. The data suggest that the difference of amino acid sequence of NS1 protein contributes to the IFN-β antagonist. In contrast, the difference of the NS1 protein does not influence in the IFN-α antagonistic activity.

Vibrio choleraeO1 Isolate with Novel Genetic Background, Thailand–Myanmar

To the Editor: Vibrio cholerae O1, a causative agent of cholera, was classified into 2 biotypes, classical and El Tor (1). However, accumulating evidence suggests that atypical El Tor V. cholerae, which possesses traits of both classical and El Tor biotypes, has replaced the seventh pandemic prototypic El Tor V. cholerae worldwide in recent years. Cholera outbreaks in Thailand during 2007–2010 were caused by atypical El Tor isolates carrying the classical type cholera toxin gene (2). Epidemiologic surveys in a Thailand–Myanmar border area during 2008 yielded more than 500 isolates of V. cholerae O1. We identified an isolate that possessed the typical El Tor type cholera toxin gene (genotype 3) and designated it MS6 (later assigned strain number DMST28216). It does not belong to either the seventh pandemic prototypic biotype identified in 1961 or the group of atypical El Tor strains found during 1991–present (3).

Identification of epitopes in Leptospira borgpetersenii leucine-rich repeat proteins

Leptospirosis is considered to be a re-emerging disease that has impacts on public health both globally and in and Thailand. The leptospires outbreak in Thailand during 1999 was largely due to the etiologic agent Leptospira borgpetersenii serogroup Sejroe. This had a related immunity profile in cows from Thailand, which serovars Tarassovi and Sejroe were prevalent. Development of a vaccine protecting against leptospiral infection in livestock has been considered. One family of proteins being targeted as candidates for vaccine development are leucine-rich repeats (LRRs), which have diverse functions such as bacterial host-pathogen interactions, membrane anchoring, invasion and stimulating host defense mechanisms. Identifying leptospiral LRR proteins containing immunogenic epitopes is important for Leptospirosis vaccine development. In this study, we searched LRR genes from L. borgpetersenii serovar Hardjo-bovis strain L550 and LB179 genomic databases in an attempt to find appropriate LRR proteins for vaccine candidates covering the common genospecies detected in Thailand. The in silico analysis, LRR protein secondary and tertiary structures by 3D modeling, and T cell epitope prediction & analysis were performed. In conclusion, we have found seven pairs of conserved LRR genes in L. borpetersenii serovars Hardjo-bovis strains JB197 and L550. Only the LBJ_2271 gene was predicted to be LRR motif subfamily membrane protein with an N-terminal signal sequence, 2 transmembrane domains and an N-glycosylated site. The LRR consensus sequence LXXLXLXXNXL was classified in a typical LRR subfamily. The LBJ_2271 gene sequence has highly homology to genes in other pathogenic Leptospira interrogans serovars; LA_1324, LIC_12401, JX26069, JX26070, JX26071 and JX06072. The LBJ_2271 protein was predicted to containin 14 T cell epitopes, 8 of which are predicted T cell epitopes for Major-Histo-Compatability (MHC) alleles HLA-A∗0101, A∗0202, A∗0203, A∗1101, A∗3101, A∗6802, and HLA-DRB∗0401 and DRB∗0701, with IC50 values of 0.90–32.28nM, residing outside of the transmembrane domains. At least 5 promising predicted T cell epitopes for alleles HLA-A0202, -A0203, -A1101, -DRB0401 and -DRB0701 had their IC50 lower – equal to IC50 values for the same allele epitopes of known antigenic proteins LigA, LipL32, OMPL1 and LipL36. This study has successfully identified LBJ_2271 as a protein candidate for further study of antigenic immune stimulation for vaccine development.

Framing risk in pandemic influenza policy and control

This article explores differing understandings of ‘risk’ in relation to pandemic influenza policy and control. After a preliminary overview of methodological and practical problems in risk analysis, ways in which risk was framed and managed in three historical cases were examined. The interdependence between scientific empiricism and political decision-making led to the mismanagement of the 1976 swine influenza scare in the USA. The 2004 H5N1 avian influenza outbreak in Thailand, on the other hand, was undermined by questions of national economic interest and concerns over global health security. Finally, the recent global emergency of pandemic influenza H1N1 in 2009 demonstrated the difficulties of risk management under a context of pre-established perceptions about the characteristics and inevitability of a pandemic. Following the analysis of these cases, a conceptual framework is presented to illustrate ways in which changing relationships between risk assessment, risk perception and risk management can result in differing policy strategies.

Poultry Production Clusters (PPCs) after AI Outbreaks in Thailand: Past, Present and Future Direction

Poultry Production Clusters (PPCs) after AI Outbreaks in Thailand: Past, Present and Future Direction

High concentrations of circulating interleukin‐6 and monocyte chemotactic protein‐1 with low concentrations of interleukin‐8 were associated with severe chikungunya fever during the 2009–2010 outbreak in Thailand

The recent outbreak of Chikungunya virus in Thailand caused a rheumatic fever associated with considerable morbidity and fatalities. Thus, it is important to identify biomarker(s) of severe disease induced by this threatening arbovirus. Putative biomarkers in cases of chikungunya fever during an outbreak in the southern part of Thailand in 2009-2010 were identified. Sixty-two patients who had developed fever and myalgia, with or without arthralgia/arthritis, were enrolled and grouped into severe chikungunya fever (CHIKF) (n= 15), mild CHIKF (n= 20) and non-CHIKF (n= 27) to investigate circulating immunological mediators that might serve as markers of severity. Blood samples were taken at presentation (day 1) and 30 days later (day 30) and plasma concentrations of interleukin (IL)-1β, IL-6, IL-8, IL-17, tumor necrosis factor-alpha, monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-1, tissue inhibitor of matrix metalloproteinase-1 and viral load were measured by ELISA. On day 1, severe CHIKF and mild CHIKF groups had viral loads of 10(8.5) and 10(8.3) of RNA copies/mL, respectively. At presentation, all CHIKF patients had circulating concentrations of IL-6 and MCP-1 higher than did non-CHIKF patients, whereas amongst the CHKF patients, the severe CHIKF patients had higher IL-6 concentrations than did mild CHIKF patients. Interestingly, severe CHIKF patients had significantly lower concentrations of circulating IL-8 than the other groups of patients, suggesting that high concentrations of IL-6 and MCP-1 with low concentrations of IL-8 may be a determinant of severe chikungunya virus infection.

Molecular insights into the binding affinity and specificity of the hemagglutinin cleavage loop from four highly pathogenic H5N1 isolates towards the proprotein convertase furin

The furin (FR) complex with each of four different sequences of hemagglutinin from the highly pathogenic H5N1 strains (HPH5), which were identified during the 2004–2010 influenza outbreaks in Thailand, were evaluated by molecular dynamics simulations, so as to compare the specificity and recognition of the enzyme–substrate binding. Relative to the conventional HPH5 inserted (H5Sq1, RERRRKKR), the S5-R or S6-R arginine residue is replaced by the smaller lysine in the H5Sq2 (RERKRKKR) and H5Sq3 (REKRRKKR) strains, respectively, whereas the S3-K lysine residue is deleted in H5Sq4 (RERRR_KR). The molecular dynamics results of the intermolecular interactions, in terms of hydrogen bonds and per-residue decomposition energy, between the substrate and furin revealed that the deletion of the positively charged amino acid at the S3 position in H5Sq4 leads to a notably weaker binding and specificity with the furin active site compared with that of FR–H5Sq1. A slight change in the substrate binding was found in the FR–H5Sq2 and FR–H5Sq3 complexes as a result of the replacement of the arginine with the shorter side-chained lysine (same positive charge). Altogether, the predicted binding free energy of the enzyme–substrate complexes was found to be in the following order: FR–H5Sq1 < FR–H5Sq2 ~ FR–H5Sq3 ≪ FR–H5Sq4.

Recombination and positive selection identified in complete genome sequences of Japanese encephalitis virus

The mosquito-borne Japanese encephalitis virus (JEV) causes encephalitis in man but not in pigs. Complete genomes of a human, mosquito and pig isolate from outbreaks in 1982 and 1985 in Thailand were sequenced with the aim of identifying determinants of virulence that may explain the differences in outcomes of JEV infection between pigs and man. Phylogenetic analysis revealed that five of these isolates belonged to genotype I, but the 1982 mosquito isolate belonged to genotype III. There was no evidence of recombination among the Thai isolates, but there were phylogenetic signals suggestive of recombination in a 1994 Korean isolate (K94P05). Two sites of the genome under positive selection were identified: codons 996 and 2296 (amino acids 175 of the non-structural protein NS1 and 24 of NS4B, respectively). A structurally significant substitution was seen at NS4B position 24 of the human isolate compared with the mosquito and pig isolates from the 1985 outbreak in Thailand. The potential importance of the two sites in the evolution and ecology of JEV merits further investigation.Electronic supplementary materialThe online version of this article (doi:10.1007/s00705-011-1143-4) contains supplementary material, which is available to authorized users.

Molecular characterization and complete genome analysis of human enterovirus 71 and coxsackievirus A16 from children with hand, foot and mouth disease in Thailand during 2008-2011

Hand, foot and mouth disease (HFMD) has mostly been caused by enterovirus 71 (EV71) and coxsackievirus A16 (CA16). CA 16 was the most common cause of HFMD in 2010. EV71 had a high prevalence in 2008-2009 and has been identified with a higher frequency since 2011. Nearly complete genome sequences of three EV71 strains (2008-2009 strains) and two CA16 strains (2010 strains) obtained from outbreaks in Thailand in 2008 to 2010 were characterized. Based on a phylogenetic tree of the complete VP1 region, three EV71 strains grouped into the B5, C1 and C4 genotypes, and two CA16 strains grouped into the C genotype. Based on sequence analysis, nucleotide changes were found to cluster in the internal ribosome entry site (IRES) element of the 5'-untranslated region (5'-UTR). Amino acid differences identified in all strains were located in the non-structural protein. These data also provide the molecular epidemiology of EV71 and CA16 outbreaks in Thailand.

Development of influenza vaccine production capacity by the Government Pharmaceutical Organization of Thailand: Addressing the threat of an influenza pandemic

In 2005, a year after highly pathogenic avian influenza outbreaks in Thailand, the Thai Government issued a National Strategy Plan for Pandemic Influenza Preparedness, a major objective of which was the domestic production of seasonal influenza vaccine. It was considered that sustained influenza vaccine production was the best guarantee of a pandemic vaccine in the event of a future pandemic. The Government decided to provide funds to establish an industrial-scale influenza vaccine production plant, and gave responsibility for this challenging project to the Government Pharmaceutical Organization (GPO). In 2007, with support from the World Health Organization (WHO), the GPO started to develop egg-based, trivalent inactivated influenza vaccine (IIV) in a renovated pilot plant. In early 2009, during the second year of the project, the GPO turned its attention to develop a pandemic live attenuated influenza vaccine (PLAIV) against the influenza A (H1N1) virus. By December 2010, the H1N1 PLAIV had successfully completed Phase II clinical trials and was awaiting registration approval from the Thai Food and Drug Administration (TFDA). The GPO has also started to develop an H5N2 PLAIV, which is expected to enter clinical trials in January 2011. The next step in 2011 will be the development and clinical evaluation of seasonal LAIV. To meet the needs of the national seasonal influenza vaccination programme, the GPO aims to produce 2 million doses of trivalent IIV in 2012 and progressively increase production to the maximum annual capacity of 10 million doses. This article relates how influenza vaccine production capacity was developed and how major challenges are being met in an expeditious manner, with strong local and global commitment.

Wild Birds and Increased Transmission of Highly Pathogenic Avian Influenza (H5N1) among Poultry, Thailand

Abstract Since the outbreaks of highly pathogenic avian influenza (HPAI) subtype H5N1 virus, wild birds have been suspected of transmitting this virus to poultry. On January 23, 2004, the Ministry of Public Health in Thailand informed the World Health Organization of an avian influenza A (H5N1) outbreak. To determine the epidemiology of this viral infection and its relation to poultry outbreaks in Thailand from 2004 through 2007, we investigated how wild birds play a role in transmission. A total of 24,712 serum samples were collected from migratory and resident wild birds. Reverse transcription PCR showed a 0.7% HPAI (H5N1) prevalence. The highest prevalence was observed during January–February 2004 and March–June 2004, predominantly in central Thailand, which harbors most of the country’s poultry flocks. Analysis of the relationship between poultry and wild bird outbreaks was done by using a nonhomogeneous birth and death statistical model. Transmission efficiency among poultry flocks was 1.7× higher in regions with infected wild birds in the given or preceding month. The joint presence of wild birds and poultry is associated with increased spread among poultry flocks.

Wild birds and increased transmission of highly pathogenic avian influenza (H5N1) among poultry, Thailand.

Since the outbreaks of highly pathogenic avian influenza (HPAI) subtype H5N1 virus, wild birds have been suspected of transmitting this virus to poultry. On January 23, 2004, the Ministry of Public Health in Thailand informed the World Health Organization of an avian influenza A (H5N1) outbreak. To determine the epidemiology of this viral infection and its relation to poultry outbreaks in Thailand from 2004 through 2007, we investigated how wild birds play a role in transmission. A total of 24,712 swab samples were collected from migratory and resident wild birds. Reverse transcription PCR showed a 0.7% HPAI (H5N1) prevalence. The highest prevalence was observed during January-February 2004 and March-June 2004, predominantly in central Thailand, which harbors most of the country's poultry flocks. Analysis of the relationship between poultry and wild bird outbreaks was done by using a nonhomogeneous birth and death statistical model. Transmission efficiency among poultry flocks was 1.7 X higher in regions with infected wild birds in the given or preceding month. The joint presence of wild birds and poultry is associated with increased spread among poultry flocks.

Wild Birds and Increased Transmission of Highly Pathogenic Avian Influenza (H5N1) among Poultry, Thailand

Since the outbreaks of highly pathogenic avian influenza (HPAI) subtype H5N1 virus, wild birds have been suspected of transmitting this virus to poultry. On January 23, 2004, the Ministry of Public Health in Thailand informed the World Health Organization of an avian influenza A (H5N1) outbreak. To determine the epidemiology of this viral infection and its relation to poultry outbreaks in Thailand from 2004 through 2007, we investigated how wild birds play a role in transmission. A total of 24,712 swab samples were collected from migratory and resident wild birds. Reverse transcription PCR showed a 0.7% HPAI (H5N1) prevalence. The highest prevalence was observed during January-February 2004 and March-June 2004, predominantly in central Thailand, which harbors most of the country's poultry flocks. Analysis of the relationship between poultry and wild bird outbreaks was done by using a nonhomogeneous birth and death statistical model. Transmission efficiency among poultry flocks was 1.7 X higher in regions with infected wild birds in the given or preceding month. The joint presence of wild birds and poultry is associated with increased spread among poultry flocks.

Simultaneous detection and subtyping of H274Y-positive influenza A (H1N1) using pyrosequencing

We investigated the frequency of H274Y-positive swine-origin 2009 A (H1N1) influenza virus outbreak in Thailand during May-August 2009. This study sought to find Oseltamivir resistance mutation H274Y by using pyrosequencing. From 8,710 real-time RT-PCR swine-origin 2009 A(H1N1) influenza virus-positive specimens, 100 randomly selected samples identified one such virus with H274Y mutation using pyrosequencing. The patient probably acquired oseltamivir resistance from natural variation, since he had never received that form of treatment before and recovered from influenza-like symptoms without using anti-influenza drugs.

The Relationship between Environmental Factors and the Onsets of Avian Influenza Outbreaks in Thailand

The relationship between environmental factors and the onsets of avian influenza virus (AIV; H5N1) outbreaks in Thailand was studied. The results show that the onsets of the disease correlate with the maximum gradient of temperature and wind speed within 24 hours, density of villages in a radius of five kilometers, and distance from the last AIV outbreak area. This study also presents how meteorological conditions have an effect on the occurrence of onsets of AIV in Thailand.

Imported Chikungunya Virus Strains, Taiwan, 2006–2009

Imported Chikungunya Virus Strains, Taiwan, 2006–2009

Electrophysiological diagnosis and patterns of response to treatment of botulism with neuromuscular respiratory failure

In this study we describe the electrophysiological findings in botulism patients with neuromuscular respiratory failure from major botulism outbreaks in Thailand. High-rate repetitive nerve stimulation testing (RNST) of the abductor digiti minimi (ADM) muscle of 17 botulism patients with neuromuscular respiratory failure showed mostly incremental responses, especially in response to >20-HZ stimulation. In the most severe stage of neuromuscular respiratory failure, RNST failed to elicit a compound muscle action potential (CMAP) of the ADM muscle. In the moderately severe stage, the initial CMAPs were of very low amplitude, and a 3-HZ RNST elicited incremental or decremental responses. A 10-HZ RNST elicited mainly decremental responses. In the early recovery stage, the initial CMAP amplitudes of the ADM muscle improved, with initially low amplitudes and an incremental response to 3- and 10-HZ RNSTs. Improved electrophysiological patterns of the ADM muscle correlated with improved respiratory muscle function. Incremental responses to 20-HZ RNST were most useful for diagnosis. The initial electrodiagnostic sign of recovery following treatment of neuromuscular respiratory failure was an increased CMAP amplitude and an incremental response to 10-20-HZ RNST. Muscle Nerve 40: 271-278, 2009.

Chinese-like Strain of Porcine Epidemic Diarrhea Virus, Thailand

Since late 2007, several outbreaks of porcine epidemic diarrhea virus (PEDV) infection have emerged in Thailand. Phylogenetic analysis places all Thai PEDV isolates during the outbreaks in the same clade as the Chinese strain JS-2004-2. This new genotype PEDV is prevailing and currently causing sporadic outbreaks in Thailand.

Indigenous sources of 2007-2008 H5N1 avian influenza outbreaks in Thailand

Outbreaks of H5N1 avian influenza show strong seasonality. It is not clear where the source of virus originates from in each new outbreak season. This study sought to understand the nature of viral resurgence in recent outbreak seasons in Thailand, where the epidemic is relatively well controlled. In such a situation, indigenous viruses surviving the inter-outbreak season would have to pass through a bottleneck. In order to look for evidence of the bottleneck effect, viral genome sequences from recent outbreaks in the country were analysed. H5N1 avian influenza viruses were isolated from six outbreaks in the rainy season and winter of 2007 through to early 2008. Most of the outbreaks were in the Yom-Nan River basin in the southern part of the northern region of the country. Sequences of these viral isolates were identified as clade 1, genotype Z, similar to viruses from previous years in the central region of the country. The sequences clustered into two groups, one of which was closely related to viruses isolated from the same area in July 2006. These analyses indicated that there was a strong bottleneck effect on the virus population and that only a few lineages remained in the area. In addition, evidence of reassortment among these viruses was found. These indicated re-emergence of viruses from a small pool of indigenous sources that had been silently perpetuated over the dry summer months. Therefore, an approach to eradicate H5N1 avian influenza from the area by eliminating these local reservoirs may be feasible and should be seriously considered.