Fig. 3. Phylogenetic analysis of VP2 gene sequences from
pangolin and related parvoviruses. The ML tree was constructed based on
VP2 gene sequences of 142 parvoviruses belonging to the
species Carnivore
protoparvovirus 1 (FPV [n = 3]; CPV-2 [n = 14] or its variants
CPV-2a [n = 68], CPV-2b [n = 8], or CPV-2c [n = 52]). The
VP2 gene sequences of FPV were used as an outgroup and rooted by the
oldest FPV sequence (FPV/Cat/US/FPV-d/64, U22189). The two pangolin
parvovirus isolates obtained in this study are indicated by red
triangle, and the reference virus is denoted by a
black triangle. Details of the several subclades
grouped close to CPV-2b or CPV-2c are presented in Fig S1. The scale bar
shown at the bottom of the tree denotes.
Pangolins remain critically endangered worldwide, owing to a range of
threats, not least of which is pathogen infection. To date, however,
there have been few studies that have examined the pathogens infecting
pangolins. In this study, however, we were able to confirm CPV-2c
infection among pangolins inhabiting mainland China and established that
these animals can also be infected with the CPV-2a variant. In this
regard, the findings of previous studies have provided evidence to
indicate that CPV frequently undergoes interspecies transmission among
domestic and wild animals, with asymptomatic individuals (e.g., stray
dogs and raccoons) inhabiting the peripheries of urban areas acting as
virus reservoirs that promote the spread of CPV-2 to wild animals
(Allison et al., 2012; Allison et al., 2013; Hirsch, Prange, Hauver, &
Gehrt, 2013). Notably, the two strains detected in this study are
phylogenetically close to CPV strains derived from dogs. Moreover, stray
dogs have been observed attacking wild pangolins in areas in which urban
development has encroached on the habitats of these animals (S. L. Wang
et al., 2020), thereby indicating the potential for cross-species
transmission between stray dogs and wild pangolins.
In summary, in this study, we report the infection of Chinese pangolins
with two strains of canine parvovirus type 2 causing diarrheal diseases.
These two CPV-2 strains are closely related to CPV-2a and CPV-2c, which
are prevalent in China and neighboring countries, respectively, thereby
revealing that the CPV-2 strains infecting Chinese pangolins are related
to those known to be of dog origin. Based onour findings, we recommend
that further investigations should be conducted to assess the potential
interspecies transmission among wild Chinese pangolins and domestic or
feral dogs.