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84 Canine Influenza Virus 867

Canine influenza virus survives in the environment for shed contagious virus. Dogs will completely recover clin-
VetBooks.ir more than 24 hours. Because secondary bacterial and ically within 2–3 weeks, sometimes, however, with a lin-
gering cough. Animals that are generally in good health
mycoplasma infections can cause complications, antimi-
crobials may be considered if clinical signs are severe or
plications. While most infections will be self‐limiting,
suggest co‐infection. Antiviral drugs exist for influenza, and well nourished are expected to recover without com-
but such treatments have not been approved for use in mortality is considered to be between 1% and 5%.
dogs. Information is lacking regarding their efficacy,
doses or negative side‐effects in dogs.
The Nobivac® Canine Influenza H3N8 and H3N2 inacti- Public Health Implications
vated bivalent vaccine from Intervet/Merck is labelled as
effective at reducing disease severity. However, the capac- With the reported transmissions of influenza from birds
ity for influenza A viruses to mutate provides the risk of and other mammals to humans, we should consider CIV
eventual adaptation and evasion of immunity from admin- strains a potential public health concern. Influenza
istered vaccines. viruses are commonly transmitted across species
although usually with subclinical infection and without
further transmission within the second species. However,
Prognosis the CIV strains have not been reported to infect humans,
even owners with known infected dogs, and the Centers
From 60% to 80% of CIV‐infected dogs will present with for Disease Control does not consider the canine influ-
clinical illness, but subclinically infected dogs will also enza viruses to be a human threat.

Further Reading

Crawford PC, Dubovi EJ, Castleman WL, et al. Song DS, An DJ, Moon HJ, et al. Interspecies transmission
Transmission of equine influenza virus to dogs. Science of the canine influenza H3N2 virus to domestic cats in
2005; 310(5747): 482–5. South Korea. J Gen Virol 2011; 92(Pt 10): 2350–5.
He W, Li G, Zhu H, et al. Emergence and adaptation of Song D, Moon HJ, An DF, et al. A novel reassortant canine
H3N2 canine influenza virus from avian influenza virus: H3N1 influenza virus between pandemic H1N1 and
an overlooked role of dogs in interspecies transmission. canine H3N2 influenza viruses in Korea. J Gen Virol
Transbound Emerg Dis 2019; 66(2): 842–51. 2012; 93(Pt 3): 551–4.
Ramírez‐Martínez LA, Contreras‐Luna M, De la Luz J, Su S, Wang L, Fu X, et al. Equine influenza A (H3N8) virus
et al. Evidence of transmission and risk factors for infection in cats. Emerg Infect Dis 2014; 20(12): 2096–9.
influenza A virus in household dogs and their Voorhees IEH, Glaser AL, Toohey‐Kurth K, et al. Spread of
owners. Influenza Other Respir Viruses 2013; 7(6): canine influenza A(H3N2) virus, United States. Emerg
1292–6. Infect Dis 2017; 23(12): 1950–7.