Susceptibility of common family Anatidae bird species to clade 2.3.4.4e H5N6 high pathogenicity avian influenza virus: an experimental infection study.

BACKGROUND: There were large outbreaks of high pathogenicity avian influenza (HPAI) caused by clade 2.3.4.4e H5N6 viruses in the winter of 2016-2017 in Japan, which caused large numbers of deaths among several endangered bird species including cranes, raptors, and birds in Family Anatidae. In this study, susceptibility of common Anatidae to a clade 2.3.4.4e H5N6 HPAI virus was assessed to evaluate their potential to be a source of infection for other birds. Eurasian wigeons (Mareca penelope), mallards (Anas platyrhynchos), and Northern pintails (Anas acuta) were intranasally inoculated with 106, 104, or 102 50% egg infectious dose (EID50) of clade 2.3.4.4e A/teal/Tottori/1/2016 (H5N6). RESULTS: All birds survived for 10 days without showing any clinical signs of infection. Most ducks inoculated with ≥ 104 EID50 of virus seroconverted within 10 days post-inoculation (dpi). Virus was mainly shed via the oral route for a maximum of 10 days, followed by cloacal route in late phase of infection. Virus remained in the pancreas of some ducks at 10 dpi. Viremia was observed in some ducks euthanized at 3 dpi, and ≤ 106.3 EID50 of virus was recovered from systemic tissues and swab samples including eyeballs and conjunctival swabs. CONCLUSIONS: These results indicate that the subject duck species have a potential to be a source of infection of clade 2.3.4.4e HPAI virus to the environment and other birds sharing their habitats. Captive ducks should be reared under isolated or separated circumstances during the HPAI epidemic season to prevent infection and further viral dissemination.

Limited expression of functional cytochrome p450 2c subtypes in the liver and small intestine of domestic cats.

1. Compared to information for herbivores and omnivores, knowledge on xenobiotic metabolism in carnivores is limited. The cytochrome P450 2C (CYP2C) subfamily is recognized as one of the most important CYP groups in human and dog. We identified and characterized CYP2C isoforms and variants in cat, which is an obligate carnivore. 2. Quantitative RT-PCR and immunoblot analyses were carried out to evaluate the expression of CYP2C in the liver and small intestine. A functional CYP2C isoform was heterologously expressed in yeast microsomes to determine the enzymatic activity. 3. Cat had two CYP2C genes, 21 and 41, in the genome; however, CYP2C21P was a pseudogene that had many stop codons. Three splicing variants of CYP2C41 were identified (v1-v3), but only one of them (v1) showed a complete deduced amino acid sequence as CYP2C protein. Transcripts of feline CYP2C41v1 were detected but the amounts were negligible or very small in the liver and small intestine. Immunoreactivity to an antihuman CYP2C antibody was confirmed in the recombinant feline CYP2C41v1 but not in the feline liver. 4. Recombinant feline CYP2C41v1 metabolized several substrates, including dibenzylfluorescein that is specific to human CYP2C. 5. The results suggest a limited role of functional CYP2C isoforms in xenobiotic metabolism in cat.