Detection and Phylogenetic Analysis of Herpesviruses Detected in Wild Owls in Slovenia

Herpesvirus Infection in a Breeding Population of Two Coexisting Strix Owls

“…Although that some studies have suggested that raptors may contract the infection and consequently disease through the oral route by ingesting CoHV 1 infected pigeons [ 7 ], the detection of the partial sequence of herpesvirus DNA polymerase gene in healthy owls raises the question whether all herpesvirus infections in this species [ 7 , 24 ] cause illness with a fatal outcome in some cases. GaHV 2, also known as Marek’s disease virus [ 11 ], CoHV 1 [ 7 , 10 , 11 ], StHV 1 [ 16 ], and the herpesviruses detected in our previous [ 11 ] and present study are currently known herpesviruses in owls. They are genetically different, and it could be possible that some of them, such as CoHV 1, are a more fatal threat to owls than others, and also that they could differ from each other in transmission and pathogenesis.…”

“…Diverse herpesviruses have frequently been found in different free-living bird species [ 7 , 8 , 9 , 10 , 11 ]. In owls, herpesvirus was discovered in the 1970s [ 12 ], later known as Strigid herpesvirus (StHV 1), and it has been reported in captive and free-ranging owls in Asia, Europe, North America, and Australia [ 10 ].…”

“…Earlier studies of owl herpesvirus in Europe reported that, on the one hand, the virus can be lethal to some owl species but non-infective to some others, especially species with dark eyes (i.e., the tawny owl ( Strix aluco ) and barn owl ( Tyto alba ) [ 18 , 19 ]), while the third European owl species with dark eyes, the Ural owl ( Strix uralensis ), was not tested. A later study, which included Ural owls as well, did not confirm this hypothesis but indicated that polymorphic species are seemingly more resistant than the species showing lower variability in overall plumage color [ 11 ]. However, all of these studies were conducted on dead or injured birds from wildlife rehabilitation centers or birds in laboratory experiments rather than in free-living wild populations.…”

“…Based on a partial herpesvirus DNA polymerase sequence phylogenetic study showed that herpesvirus in owls and herpesvirus endemic in the pigeon population—namely, Columbid herpesvirus 1 (CoHV 1)—are the same virus, and that the pigeons are responsible for transmission of the virus to the owls [ 7 , 24 ]. However, a recent study of phylogenetic analysis of herpesvirus DNA polymerase partial nucleotide sequences detected in dead owls showed that owls were also infected with herpesviruses that are divergent from CoHV 1 [ 11 ]. In general, inhalation of virus-containing dust derived from feathers, nasal excretion, saliva, nasal discharge, urine, feces, and crop milk is the predominant means of herpesvirus transmission in birds, and no vertical transmission has been proven [ 25 ].…”

“…To the best of our knowledge, this study is the first on herpesvirus in owls conducted in the wild breeding owl population. We studied two closely related, ecological similar, and coexisting owl species, the Ural owl and tawny owl [ 26 ], which were found to have different susceptibility to herpesvirus infection in previous study on dead birds [ 11 ]. In Europe, the Ural and tawny owl largely overlap in range, habitat, prey, and nest site selection [ 26 , 27 , 28 ], indicating close contact between the species and thus high exposure to interspecific virus transmission.…”