Abstract:
Recent reports of the detection of the zoonotic low pathogenic avian influenza (LPAI) H7N9
viruses in healthy pigeons have again put the spotlight on the potential role of pigeons and
doves in the transmission of avian influenza between infected poultry and humans. A
surge in studies followed the highly pathogenic avian influenza (HPAI) H5N1 epidemic,
and this review collates the new data on AIV in pigeons and doves, both from a surveillance
perspective, as well as the results of numerous clinical studies. Collectively, results of 32
field studies representing 24 countries across four continents indicate an antibody
prevalence of 8.01% in pigeons and doves but only 0.37% of the total was associated with
exposure to the same serotype as a highly pathogenic avian influenza (HPAI) outbreak
occurring in poultry at the time. Only 1.1% of 6155 columbids sampled tested positive for
the virus, and only 9/6155 (0.15%) viruses were detected in regions that were experiencing
outbreaks of a notifiable serotype at the time.
In 22 experimental infection studies with HPAI and LPAI viruses since 1944, only
26/715 (3.64%) mortalities were reported, and these could usually be associated with
excessive doses of inoculum, which would induce fatal inflammatory responses. Since
seroconversion and virus detection was demonstrated in many of these studies, albeit
without clinical signs in most cases, it is clear that columbids are susceptible to infection,
but ineffective propagators and disseminators of the virus, i.e. ‘‘dead end’’ hosts for AIVs,
even HPAI. Viruses are shed in minute quantities from both the choana and in the feces for
a short duration but titers are below the minimum threshold require to infect other
species.
