Detection of avian metapneumovirus field infection via reverse transcriptase polymerase chain reaction (RT-PCR) and ELISA in two layer farms in Johore

Avian metapneumovirus (AMPV) infection which is known as 'swollen head syndrome' has been shown to be prevalent in poultry farms in Malaysia. Two layer farms in Johor denoted as Farm A and Farm B, with previous history of AMPV disease outbreak, were the subjects used for the AMPV field investigation in this study. Thirty chicks from respective treatment groups were monitored at day old, two, four and six weeks of age for AMPV antibody and antigen detection. RT-PCR and ELISA serology indicate that at 2 weeks of age. AMPV field infection had occured in Farm A. In Farm B, AMPV field infection or lateral spread of vaccine was observed as early as 2 weeks. AMPV seroconversion was generally observed at four weeks of age and AMPV subtypes A and B were detected via RT-PCR from both farms in this study. This is the first report of AMPV subtypes A and B by RT-PCR detection in Malaysia

Genetic characterization of Porcine Circovirus 2 found in Malaysia

Background: Porcine circovirus type 2 is the primary etiological agent associated with a group of complex multi-factorial diseases classified as Porcine Circovirus Associated Diseases (PCVAD). Sporadic cases reported in Malaysia in 2007 caused major economic losses to the 2.2 billion Malaysian ringgit (MYR) (approximately 0.7 billion US dollar) swine industry. The objective of the present study was to determine the association between the presence of PCV2 and occurrences of PCVAD. Results: This study showed that 37 out of 42 farms sampled were positive for PCV2 using PCR screening. Thirteen whole genome of PCV2 isolates from pigs with typical PCVAD symptoms were successfully sequenced. These isolates shared 98.3-99.2% similarities with sequences of isolates from the Netherlands. All thirteen isolates fell into the same clade as PCV2b isolates from other countries. Amino acid sequence analysis of the putative capsid protein (ORF2) of the PCV2 revealed that there are three clusters found in Malaysia, namely cluster 1C and 1A/1B. Of interest, three of the isolates (isolates Mal 005, Mal 006 and Mal 010) had a proline substitution for arginine or isoleucine encoded at nt. position 88-89. Eight of the isolates had mutations at the C terminus of the putative capsid protein suggestive of higher pathogenicity which may account for the high reports of PCVAD clinical symptoms in 2007. Conclusion: Phylogenetic study suggests that there may be a link between movements of animals by import of breeders into the country being the route of entry of the virus. While it is not possible to eradicate the virus from commercial pigs, the swine industry in Malaysia can be safeguarded by control measures implemented throughout the country. These measures should include improved biosecurity, disease surveillance; vaccination as well as enforcement of regulations formulated to control and prevent the spread of this disease on a national scale

Observation of risk factors, clinical manifestations and genetic characterization of recent Newcastle disease virus outbreak in West Malaysia

Background: Newcastle disease virus remains a constant threat in commercial poultry farms despite intensive vaccination programs. Outbreaks attributed to ND can escalate and spread across farms and states contributing to major economic loss in poultry farms. Results: Phylogenetic analysis in our study showed that eleven of the samples belonged to genotype VIId. All farms were concurrently positive with two immunosuppressive viruses; Infectious Bursal Disease Virus (IBDV) and Marek’s Disease Virus (MDV). Amino acid sequence analysis confirmed that eleven of the samples had sequence motifs for velogenic/mesogenic strains; three were lentogenic. Conclusion: In conclusion, no new NDV genotype was isolated from the 2011 NDV outbreak. This study suggests that the presence of other immunosuppressive agents such as IBD and MDV could have contributed to the dysfunction of the immune system of the chickens, causing severe NDV outbreaks in 2011. Risk factors related to biosecurity and farm practices appear to have a significant role in the severity of the disease observed in affected farms

Phylogenetic characterization of genes encoding for viral envelope glycoprotein (ORF5) and nucleocapsid protein (ORF7) of porcine reproductive & respiratory syndrome virus found in Malaysia in 2013 and 2014

Background: Porcine reproductive and respiratory syndrome (PRRS) is one of the most expensive diseases of modern swine production & results in annual economic losses and cost the industry over 600 million USD in U.S. alone and billions of dollars worldwide. Two atypical PRRS cases were observed in 2013 and 2014 characterized by late-term abortion, fever and sudden increase in sow mortality which persisted for a prolonged period of time. Methods: Lungs, lymph nodes and other samples were collected for disease investigation. Sequencing of the viral envelope glycoprotein (ORF5) and nucleocapsid protein (ORF7) of PRRSV was done using the BigDye Terminator v3. 1 cycle sequencing kit chemistry. The phylogenetic tree was constructed by using the Maximum Likelihood method, generated by Mega 6.06®. Results: Analysis of the ORF5 and ORF7 showed high degree of sequence homology to PRRSV parent vaccine strain VR-2332, RespPRRSV and other mutant/chimeric virus strains. Conclusions: Our study suggests that recombination events between vaccine strains and field isolates may contribute to PRRSV virulence in the field

Molecular characterization of porcine circovirus

A study was done to determine the occurrence of porcine circoviruses in Malaysia. Porcine Circovirus 2 (PCV2) is the causative agent of Porcine Circovirus associated Diseases (PCVAD), of which Post Weaning Multisystemic Wasting Syndrome (PMWS) is the most important. The virus is of huge economic significance worldwide. Globally, the virus and disease has been reported in Canada, US, several European countries and in Asia. In Malaysia PCV2 was first identified by the Veterinary Research Institute in 2004 by RFLP methods followed by the first case study of PCVAD in 2007 based on clinical features, histopathology findings and PCR screenings. The objectives were to detect PCV2 from selected pig farms and to genetically characterize them. Understanding the presence of the virus may contribute to better vaccination programs against the virus which may control the disease manifestation. At the time the samples were collected, PCV2 vaccines were not available in Malaysia. Therefore, this study will represent the complete phylogenetic characterization of PCV2 reported for the first time in Malaysia from samples collected in 2007. To meet the objective of the study, organ samples were collected from 42 selected pig farms in Malaysia (Penang, Perak, Selangor, Melaka,Johor and Sarawak). The organ samples were collected from animals that demonstrated typical clinical signs of PCVAD such as wasting, weight loss, stunted in growth, dyspnea, lymph nodes enlargement, diarrhea, pallor and jaundice. A total of five pigs were sampled from each farm. For the end analysis, the organs were pooled and screened by PCR to represent the data in each farm. Among the 42 farms,39 were positive for PCV, while three farms indicate negative result. Subsequently, a phylogenetic tree was constructed from 13 representative positive PCV2 samples to represent the six states of which samples were collected from. All 13 selected samples fell into the same clade as other PCV2b isolates from other countries. Amino acid sequence analysis of the putative capsid protein (ORF2) of the PCV2 revealed that there are three clusters found in Malaysia, namely cluster 1C and 1A/1B. The hyper variable regions of the ORF2 of PCV2 was analyzed by utilizing a differentiation of wild-type vs. vaccine-type strain (DIVA) assay by real-time PCR which was developed in this study in order to distinguish and differentiate the strains isolated in this study. Analysis by DIVA assay which targeted the hyper variable regions confirmed that all isolates were wild-type PCV2 with no association with vaccine strains. Overall, our study suggests that there may be a link between movements of animals by import of breeders into the country being the route of entry of the virus. However, more investigations are needed to confirm this

RESEARCH ARTICLE Open Access Observation of risk factors, clinical manifestations and genetic characterization of recent Newcastle Disease Virus outbreak in West Malaysia

Background: Newcastle disease virus remains a constant threat in commercial poultry farms despite intensive vaccination programs. Outbreaks attributed to ND can escalate and spread across farms and states contributing to major economic loss in poultry farms. Results: Phylogenetic analysis in our study showed that eleven of the samples belonged to genotype VIId. All farms were concurrently positive with two immunosuppressive viruses; Infectious Bursal Disease Virus (IBDV) and Marek’s Disease Virus (MDV). Amino acid sequence analysis confirmed that eleven of the samples had sequence motifs for velogenic/mesogenic strains; three were lentogenic. Conclusion: In conclusion, no new NDV genotype was isolated from the 2011 NDV outbreak. This study suggests that the presence of other immunosuppressive agents such as IBD and MDV could have contributed to the dysfunction of the immune system of the chickens, causing severe NDV outbreaks in 2011. Risk factors related to biosecurity and farm practices appear to have a significant role in the severity of the disease observed in affected farms

Guideline for herbal medicine research

Herbal medicine is widely used in Traditional and Complementary Medicine (T&CM) practices. With its increasing use within the Malaysian community, there needs to be more specific guidance on the requirements for herbal medicine research to produce evidence-based herbal medicine products with therapeutic claims. Therefore, the pathway of herbal product development involving preclinical and clinical research must be well outlined in tandem with the ‘Guideline on Natural Products with Therapeutic Claim’ from the regulators. The primary purpose of this guideline is to provide structured guidance to be utilised by researchers, academicians, clinicians, T&CM practitioners, and relevant stakeholders of the herbal industry. This guideline outlines a concise yet informative description of the prerequisites and processes involved in planning and conducting herbal medicine-related research in the Malaysian context. This guideline will bridge the gap often associated with the population's demand for other treatment options besides conventional medicine. This effort will also help accommodate the growing interest in herbal medicine research and spur the discovery of herbal products with therapeutic claims in Malaysia