Molecular characterization of highly pathogenic avian influenza H5N8 viruses isolated from Baikal teals found dead during a 2014 outbreak in Korea

Nineteen highly pathogenic avian influenza (HPAI) H5N8 viruses were isolated from wild birds in the Donglim reservoir in Gochang, Jeonbuk province, Korea, which was first reported to be an outbreak site on January 17, 2014. Most genes from the nineteen viruses shared high nucleotide sequence identities (i.e., 99.7% to 100%). Phylogenetic analysis showed that these viruses were reassortants of the HPAI H5 subtype and the H4N2 strain and that their hemagglutinin clade was 2.3.4.4, which originated from Eastern China. The hemagglutinin protein contained Q222 and G224 at the receptor-binding site. Although the neuraminidase protein contained I314V and the matrix 2 protein contained an S31N substitution, other mutations resulting in oseltamivir and amantadine resistance were not detected. No substitutions associated with increased virulence and enhanced transmission in mammals were detected in the polymerase basic protein 2 (627E and 701D). Non-structural-1 was 237 amino acids long and had an ESEV motif with additional RGNKMAD amino acids in the C terminal region. These viruses caused deaths in the Baikal teal, which was unusual, and outbreaks occurred at the same time in both poultry and wild birds. These data are helpful for epidemiological understanding of HPAI and the design of prevention strategies.

First detection of West Nile virus in domestic pigeon in Korea

West Nile virus (WNV) is a mosquito-borne zoonotic pathogen that has spread throughout Europe and the United States. Recently, WNV spread to East and Southeast Asia, and great efforts have been made in South Korea to prevent the spread of WNV from neighboring countries. In this study, we diagnosed the first case of WNV in pigeons (Columba livia domestica) residing in cities using a competitive enzyme-linked immunosorbent assay and confirmed it with nested reverse transcription polymerase chain reaction analysis and sequencing. This is the first report to provide convincing evidence that WNV is present within South Korea.

Detection and Molecular Characterization of Cryptosporidium spp. from Wild Rodents and Insectivores in South Korea

In order to examine the prevalence of Cryptosporidium infection in wild rodents and insectivores of South Korea and to assess their potential role as a source of human cryptosporidiosis, a total of 199 wild rodents and insectivore specimens were collected from 10 regions of South Korea and screened for Cryptosporidium infection over a period of 2 years (2012-2013). A nested-PCR amplification of Cryptosporidium oocyst wall protein (COWP) gene fragment revealed an overall prevalence of 34.2% (68/199). The sequence analysis of 18S rRNA gene locus of Cryptosporidium was performed from the fecal and cecum samples that tested positive by COWP amplification PCR. As a result, we identified 4 species/genotypes; chipmunk genotype I, cervine genotype I, C. muris, and a new genotype which is closely related to the bear genotype. The new genotype isolated from 12 Apodemus agrarius and 2 Apodemus chejuensis was not previously identified as known species or genotype, and therefore, it is supposed to be a novel genotype. In addition, the host spectrum of Cryptosporidium was extended to A. agrarius and Crosidura lasiura, which had not been reported before. In this study, we found that the Korean wild rodents and insectivores were infected with various Cryptosporidium spp. with large intra-genotypic variationa, indicating that they may function as potential reservoirs transmitting zoonotic Cryptosporidium to livestock and humans.