ARS | Publication request: Urban rats or flying heroes? What can rock pigeons tell us about helminth and virus co-infection?

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 21, 2012
Publication Date: December 22, 2012
Citation: Ayala, A.J., Miller, P.J., Ezenwa, V.O. 2012. Urban rats or flying heroes? What can rock pigeons tell us about helminth and virus co-infection? [abstract]. Meeting Abstract. p.10.

Interpretive Summary: Very often single diseases are studied in wild animals even though they are infected with multiple disease causing organisms at the same time. It is known that parasites are commonly found in wild birds and that their presence can affect the animals’ susceptibility to other disease causing organisms. This study looks at the amount and type of stomach worms found in wild Rock Pigeons and the amount of a pigeon paramxyovirus serotype 1 found in these same birds to see if the worms make the pigeons more easily infected by the virus. If having high amounts of worms increases the ability of the birds to be infected with pigeon paramyxovirus seroptype 1 then treating pigeons for worms could decrease the amount of virus each bird is shedding into the environment. The pigeon paramyxovirus serotype 1 is a threat to chickens because the birds would have to be killed and not used for production.

Technical Abstract: Emerging diseases are rapidly becoming a global conservation issue, and traditional approaches to understanding transmission among in-situ populations often involved investigating hosts in the context of a single pathogen. Yet it is clear now that understanding disease dynamics within ecological frameworks must address hosts as simultaneously infected with multiple organisms. Helminths are among the most common parasites of vertebrates, yet their impact on host populations are underappreciated due to their typical sublethal and/or subclinical effects. However, helminths may indirectly play a central role in the spread of other virulent pathogens, including many microparasites (e.g. viruses, bacteria). These indirect effects occur because pre-existing helminth infections can suppress host immunity in ways that increase microparasite susceptibility and enhance infectiousness, two key parameters that influence microparasite transmission. This study examines free-ranging urban Rock Pigeons naturally exposed to both gastrointestinal helminths and Pigeon Paramyxovirus-1 virus (PPMV-1) in North-Central Georgia to examine implications of helminth co-infection for microparasite transmission. Preliminary results show that 98.7% of wild caught pigeons were infected with gastrointestinal helminths. Hatch-year birds shed fewer parasite eggs than adults, and birds with more flight feather wear shed fewer eggs. Ongoing work will examine whether widespread helminth infections in pigeons are associated with the seroprevalence of PPMV-1 and viral shedding rates.