Influenza A Virus in Camels

About half a century ago the avian Influenza A(H3N8) virus jumped to horses, mutating to the equine Influenza A (H3N8) virus or Influenza A/Equine-2. See here. Then, in 2004, it was reported that this virus again breached a species barrier and was now infecting dogs as canine Influenza A(H3N8). See here.

Influenza A/Equine-2 was first recognized in 1963 as a cause of widespread epidemics and has become endemic in many countries. Mongolia is home to recurring epizootic outbreaks of this particular Influenza A virus. These outbreaks, which occur roughly once a decade, not only impact the lives and economy of nomadic Mongolians, it has the potential of infecting other mammals.

While not as plentiful as horses, the Bactrian camel (Camelus bactrianus) is an important domesticated beast of burden for these nomadic Mongolians, and as such is frequently exposed to both humans and horses. It is also on the critically endangered list and may already be extinct in the wild.

[Image: jamo.mn]

In the fall of 1979 a severe epizootic influenza broke out among Mongolian camels, which turned out to be a reassortant of the recently re-emerged (1977) Influenza A(H1N1) virus (also known as the `Russian flu’), showing that this species of camels was susceptible to at least some strains of influenza.

Anecdotal reports of signs of respiratory illness in Bactrian camels were the reason to take a closer look at these camels and their potential infectious diseases. Nasal swab specimens were collected from seemingly healthy Bactrian camels in Mongolia during 2012. One specimen was positive for influenza A/camel/Mongolia/335/2012(H3N8), which is phylogenetically related to equine influenza A(H3N8) virus and probably represents natural horse-to-camel transmission[1].

[1] Myagmarsukh Yondon, Batsukh Zayat et al: Equine Influenza A(H3N8) Virus Isolated from Bactrian Camel, Mongolia in Emerging Infectious Diseases - 2014