Abstract
Avian influenza A viruses occasionally cross the barrier to infect species other than birds. The novel H5N1 and H7N9 influenza viruses causing endemics in human are the examples of bird-to-human transmission . To date, highly pathogenic avian influenza (HPAI) viruses belong to H5 or H7 subtypes. HPAI viruses can cause high mortality in poultry, and the viruses spread rapidly and result in huge economic losses. Besides H5 and H7 subtypes, H10 is one of the subtypes to have the potential of threatening poultry or human. There are many records of the H10 subtype viruses infecting poultry or mammalian, and some of the infection cause serious damage or human death. In our surveillance on avian influenza viruses in wild birds, we isolated two strains of H10 subtype virus in 2013. The viruses showed very weak HA genome signal in PCR subtyping system. Genomic sequences of both strains suggested that the strains derived from reassortment of Eurasian and North American lineages.
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Abstract
The oomycete Aphanomyces astaci is the etiology of crayfish plague and has devastated native crayfish populations across Europe due to introducing the infected North American crayfish. In the end of 2013, the first outbreak of A. astaci infection in cultivated Australian crayfish (Cherax quadricarinatus) was diagnosed in Taiwan. The crayfish specimens were collected from Miaoli, Changhua and Pingtung to establish a diagnosis procedure for crayfish plague. The pathological examinations with special staining revealed penetration of hyphae and granulomatous inflammation in chitinous layer of uropod and articulation. Aphanomyces astaci was not successfully isolated from these specimens based on OIE Manual of Diagnostic Tests for Aquatic Animals. For molecular diagnosis, PCR amplications of internal transcribed spacer (ITS) and chitinase gene fragments were performed and the product sequences analyzed by BLAST showed high identities with A. astaci. In addition, detecting limits between PCR and real-time PCR targeting ITS fragment were compared. By microsatellite genotyping method, genotype D was assumed according to the size of two gene fragments. This study established pathological and molecular diagnoses of crayfish plague.
A total of 217 samples was collected for electron microscopy by negative stain from June to November in 2014, including 39 samples from poultry, 61 samples from herbivores, 32 samples from aquatic animals, 42 samples from swine, and 43 samples for pathogen observation. Forty-five of those specimens were observed with specific viron/bacteria.
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