2016-17 Rapid Ag: Surveillance for High-consequence Poultry Diseases in Wild Bird Reservoirs: Influenza and Newcastle Disease
Patrick T. Redig
Veterinary Clinical Sciences
- 2016 Fiscal Year: $140,509
- 2017 Fiscal Year: $140,509
We propose to develop and field-test an efficient, economic and sustainable surveillance strategy for high-consequence viruses in wild bird populations, namely Avian Influenza and Newcastle Disease (cormorant variant), in order to allow the poultry industry and regulators to anticipate outbreaks and protect the agricultural industry.
The recent history of introduction of highly pathogenic influenza (H5N2) in North America & Minnesota is well-known at this point (Ip et al. 2015). Briefly, an Asian high path strain (EU H5N8 ) found in Korea, Japan, Siberia, Germany and the Netherlands between January and November 2014 (Verhagen et al 2014) was presumably transported by migrating waterfowl to North America (AM) in the fall of 2014 where it comingled with other AM strains and generated a re-assortant H5N2 that was carried southward across the continent in the fall in migrating waterfowl. It appears likely that these birds intermingled with resident waterfowl during migration and others on the wintering grounds in the Gulf. These viruses appear to cause little or no morbidity or mortality in waterfowl, so they circulate undetected. Outbreaks in Minnesota poultry began to occur in turkeys in late February 2015, commensurate with early dispersal of wintering resident birds. The outbreak was then reinforced by the cohort of waterfowl migrating north from the Gulf in March-April.
For a time, there was active surveillance for HP influenza viruses (Bevins, Piaggio) however, at the time of the outbreaks in the spring of 2015, there was no ongoing surveillance in wild birds. In response, the DNR and Wildlife Services have now implemented a tactical surveillance effort. However, lacking ongoing future surveillance, it is inevitable that industry will be repeatedly blind-sided with introductions and outbreaks leading to millions of dollars of direct and indirect losses as evidenced by the recent outbreaks.
With numerous outbreaks (22 at time of writing) reported in the spring of 2015 in Minnesota turkeys resulting in the death or depopulation of well over 1,400,000 birds), international trade embargoes on poultry, and millions of dollars of direct and indirect losses to producers so far, it is clear that there is an overwhelming need to have a surveillance system in place that a) detects presence, timing, and geographic distribution of both HP and LP AI viruses, b) deduces the mechanisms and means by which the virus is transported from its reservoir sources (waterfowl) to poultry facilities, and c) provides producers with up-to-date information that can be used to inform necessary biosecurity measures that will be needed to break the link between reservoir and poultry facility.
An effective, efficient, ongoing surveillance program should yield real-time information as to the complement of AI viruses circulating in central Minnesota and adjoining regions as well as recent introductions or mutations to pathogenic forms that could be introduced into poultry operations. With time and enough data, it may be possible to develop predictive models that would anticipate likelihood of certain outbreaks. Recent events have shown that surveillance conducted in years past is of little use in forewarning impending events, given the dynamic nature of influenza virus mutation rates (Fries, 2015) and the now demonstrated potential for introductions of viruses originating in Asia.
We hypothesize that overwintering waterfowl, a mix of resident and migrant birds which number in the thousands in the Twin Cities area at known locations, circulate avian influenza viruses that are the source of introductions into poultry when the ducks disperse in the spring. In addition there are many other over-wintering sites where the ducks are not directly accessible, but sampling of their fecal residues in the environment may yield similarly useful information. Therefore, intensive sampling of these birds and sites, which are accessible by various means, will yield information about the extant virus population; such information may be useful in forecasting potential threats.
Conventional sampling of waterfowl. Both live trapped and hunter-killed birds will be sampled by oropharyngeal swabbing (see table 1). Sampling will focus on defining the complement of influenza viruses that are introduced into and maintained in over-wintering waterfowl in central Minnesota. In addition, ducklings admitted to rehabilitation centers and eggs in nests of wild bird will be analyzed for maternal antibody as a means of serologically determining previous exposure to the hens to influenza and Newcastle viruses.
Assessmentof environmental sampling techniques. Freshly deposited fecal material, subsurface sediments (i.e. not impacted by UV radiation), and water in resident waterfowl habitat will be analyzed for virus geospatially concurrent with collections from live birds (above) with the goal of establishing sensitivity of such methods. While fecal sampling has been widely used (McLean et al), it is labor-intensive and has a low yield. Methodologies for sediment and water sampling have the potential for effective and efficient sampling, but they are largely in a nascent state of implementation and further testing is needed in order to establish their utility. Given the need for such methods in order to effectively conduct long-term surveillance, they are an important part of this proposal.