Disentangling the role of wild birds in avian metapneumovirus (aMPV) epidemiology: A systematic review and meta‐analysis

Abstract

Given the avian metapneumovirus (aMPV) disease burden in poultry worldwide and the evidence of a possible role played by wild birds in the virus epidemiology, the present study summarizes aMPV serological and molecular data on free‐ranging avifauna available in the literature by conducting a systematic review and meta‐analysis. A computerized literature research was performed on PubMed, Scopus, CAB Direct and Web of Science to identify relevant publications across the period 1990–2021, along with the screening of reference lists. A random‐effect model was applied to calculate pooled prevalence estimates with 95% confidence intervals. The inconsistency index statistic (I2) was applied to assess between‐study heterogeneity. Subgroup analyses for molecular studies only were performed according to geographical area of samplings, taxonomic order, genus and migration patterns of the birds surveyed. A total of 11 publications on molecular surveys and 6 on serological ones were retained for analysis. The pooled molecular prevalence was 6% (95% CI: 1–13%) and a high between‐study heterogeneity was detected (I2 = 96%, p < .01). Moderator analyses showed statistically significant differences according to geographical area studied, taxonomic order and genus. Concerning serological prevalence, a pooled estimate of 14% (95% CI: 1–39%), along with a high between‐study heterogeneity, was obtained (I2 = 98%, p < .01). Moderator analysis was not performed due to the scarcity of eligible serological studies included. Overall, molecular and serological evidence suggests that some wild bird taxa could play a role in aMPV epidemiology. Particularly, wild ducks, geese, gulls and pheasants, according to scientific contributions hereby considered, proved to be susceptible to aMPV, and due to host ecology, may act as a viral carrier or reservoir. Further surveys of wild birds are encouraged for a better comprehension of the poultry/wild bird interface in aMPV epidemiology and for better characterizing the virus host breadth.

Migratory Wild Birds as Potential Long-Distance Transmitters of Toxoplasma gondii Infection

“…In aquatic environments, intermediate avian hosts belonging to different feeding groups (herbivores, omnivores, carnivores, and insectivores) appear to be subjected to a similar infection probability [ 12 ]. In birds, several aquatic species are known hosts of relevant animal or zoonotic pathogens [ 13 , 14 , 15 , 16 , 17 ], including T. gondii [ 18 , 19 ]. Considering the ecology of waterfowl and the specialization as filter-feeders of some species, T. gondii infection in these animals suggests the presence of an oocysts-contaminated aquatic habitat.…”

Pros and Cons on Use of Live Viral Vaccines in Commercial Chicken Flocks

“…There are four (A–D) subtypes of aMPV documented, of which A and B subtypes show a worldwide distribution, whereas subtype C is reported mainly in the United States, France, South Korea, and China (43). The subtype D was only reported in France (45). Both live and inactivated subtype A and B vaccines are available globally, and cross-protection between the subtype A and B has been reported (46,47).…”

Emerging and Novel Viruses in Passerine Birds

“…Avian metapneumovirus (aMPV) is transmitted directly and causes upper respiratory tract diseases and reproductive disorders mainly in poultry, and its epidemiology, dispersal patterns, and genetic evolution are not widely known [ 139 ]. The rapid and wide dispersion of aMPV has been associated with migratory bird routes in Europe and North America, and also with international trade [ 140 ].…”