Molecular characterization of recombinant LSDV isolates from 2022 outbreak in Indonesia through phylogenetic networks and whole-genome SNP-based analysis.

Lumpy skin disease (LSD) is a transboundary viral disease of cattle and water buffaloes caused by the LSD virus, leading to high morbidity, low mortality, and a significant economic impact. Initially endemic to Africa only, LSD has spread to the Middle East, Europe, and Asia in the past decade. The most effective control strategy for LSD is the vaccination of cattle with live-attenuated LSDV vaccines. Consequently, the emergence of two groups of LSDV strains in Asian countries, one closely related to the ancient Kenyan LSDV isolates and the second made of recombinant viruses with a backbone of Neethling-vaccine and field isolates, emphasized the need for constant molecular surveillance. This current study investigated the first outbreak of LSD in Indonesia in 2022. Molecular characterization of the isolate circulating in the country based on selected LSDV-marker genes: RPO30, GPCR, EEV glycoprotein gene, and B22R, as well as whole genome analysis using several analytical tools, indicated the Indonesia LSDV isolate as a recombinant of LSDV_Neethling_vaccine_LW_1959 and LSDV_NI-2490. The analysis clustered the Indonesia_LSDV with the previously reported LSDV recombinants circulating in East and Southeast Asia, but different from the recombinant viruses in Russia and the field isolates in South-Asian countries. Additionally, this study has demonstrated alternative accurate ways of LSDV whole genome analysis and clustering of isolates, including the recombinants, instead of whole-genome phylogenetic tree analysis. These data will strengthen our understanding of the pathogens' origin, the extent of their spread, and determination of suitable control measures required.

Evidence of coinfection of pigs with African swine fever virus and porcine circovirus 2.

Archival swine DNA samples from Indonesia and Mongolia, some of which were previously shown to be positive for African swine fever virus, were screened for the presence of porcine circovirus 2 (PCV-2) and porcine circovirus 3 (PCV-3) by PCR. Samples from both countries were positive for PCV-2 (three from Mongolia and two from Indonesia), while none were positive for PCV-3. The PCV-2 amplicons were sequenced, and phylogenetic analysis revealed that the PCV-2 strains belonged to four different genotypes: PCV-2a (Mongolia), PCV-2b (Mongolia and Indonesia), PCV-2d (Indonesia), and PCV-2g (Mongolia). This is the first report of ASFV/PCV-2 coinfection in pigs and the first report of the presence of PCV-2 in Mongolia.

African swine fever in North Sumatra and West Java provinces in 2019 and 2020, Indonesia.

African swine fever (ASF) is a highly lethal and contagious viral haemorrhagic disease of domestic and wild pigs, caused by the ASF virus (ASFV). After entering China in 2018, the disease has continued to spread through Asia. In September 2019, a team from the Indonesian Research Center for Veterinary Science, Bogor, investigated outbreaks in backyard pigs in the Dairi and Humbang Hasundutan districts of North Sumatra province. In January 2020, three pigs purchased from a pig seller in Bogor District, West Java province were also tested. Real-time PCR results confirmed ASFV DNA in sixteen out of twenty-nine samples, with nine positive samples from North Sumatra and seven from West Java. Four partial or full-length genes (i.e. p72, p54, pB602L and CD2v) and a 356-bp fragment between the I73R and I329L genes were sequenced from representative samples. Phylogenetic analysis established that the ASFV in the samples from both North Sumatra and West Java were identical, indicating a common source of infection, and that they belonged to the p72 genotype II and serogroup 8. The sequences from the Indonesian ASFVs were also identical to other genotype II ASFV from domestic pigs in Vietnam, China and Russia.

Genetic diversity of the H5N1 viruses in live bird markets, Indonesia.

BACKGROUND: The live bird market (LBM) plays an important role in the dynamic evolution of the avian influenza H5N1 virus. OBJECTIVES: The main objective of this study was to monitor the genetic diversity of the H5N1 viruses in LBMs in Indonesia. METHODS: Therefore, the disease surveillance was conducted in the area of Banten, West Java, Central Java, East Java, and Jakarta Province, Indonesia from 2014 to 2019. Subsequently, the genetic characterization of the H5N1 viruses was performed by sequencing all 8 segments of the viral genome. RESULTS: As a result, the H5N1 viruses were detected in most of LBMs in both bird' cloacal and environmental samples, in which about 35% of all samples were positive for influenza A and, subsequently, about 52% of these samples were positive for H5 subtyping. Based on the genetic analyses of 14 viruses isolated from LBMs, genetic diversities of the H5N1 viruses were identified including clades 2.1.3 and 2.3.2 as typical predominant groups as well as reassortant viruses between these 2 clades. CONCLUSIONS: As a consequence, zoonotic transmission to humans in the market could be occurred from the exposure of infected birds and/or contaminated environments. Moreover, new virus variants could emerge from the LBM environment. Therefore, improving pandemic preparedness raised great concerns related to the zoonotic aspect of new influenza variants because of its high adaptivity and efficiency for human infection.

Attenuation of highly pathogenic avian influenza A(H5N1) viruses in Indonesia following the reassortment and acquisition of genes from low pathogenicity avian influenza A virus progenitors.

The highly pathogenic avian influenza (HPAI) A(H5N1) virus is endemic in Indonesian poultry and has caused sporadic human infection in Indonesia since 2005. Surveillance of H5N1 viruses in live bird markets (LBMs) during 2012 and 2013 was carried out to provide epidemiologic and virologic information regarding viral circulation and the risk of human exposure. Real-time RT-PCR of avian cloacal swabs and environmental samples revealed influenza A-positive specimens, which were then subjected to virus isolation and genomic sequencing. Genetic analysis of specimens collected at multiple LBMs in Indonesia identified both low pathogenicity avian influenza (LPAI) A(H3N8) and HPAI A(H5N1) viruses belonging to clade 2.1.3.2a. Comparison of internal gene segments among the LPAI and HPAI viruses revealed that the latter had acquired the PB2, PB1, and NS genes from LPAI progenitors and other viruses containing a wild type (wt) genomic constellation. Comparison of murine infectivity of the LPAI A(H3N8), wt HPAI A(H5N1) and reassortant HPAI A(H5N1) viruses showed that the acquisition of LPAI internal genes attenuated the reassortant HPAI virus, producing a mouse infectivity/virulence phenotype comparable to that of the LPAI virus. Comparison of molecular markers in each viral gene segment suggested that mutations in PB2 and NS1 may facilitate attenuation. The discovery of an attenuated HPAI A(H5N1) virus in mice that resulted from reassortment may have implications for the capability of these viruses to transmit and cause disease. In addition, surveillance suggests that LBMs in Indonesia may play a role in the generation of reassortant A(H5) viruses and should be monitored.

Nipah virus in the fruit bat Pteropus vampyrus in Sumatera, Indonesia.

Nipah virus causes periodic livestock and human disease with high case fatality rate, and consequent major economic, social and psychological impacts. Fruit bats of the genus Pteropus are the natural reservoir. In this study, we used real time PCR to screen the saliva and urine of P. vampyrus from North Sumatera for Nipah virus genome. A conventional reverse transcriptase (RT-PCR) assay was used on provisionally positive samples to corroborate findings. This is the first report of Nipah virus detection in P. vampyrus in Sumatera, Indonesia.