The Parasitic Eyeworm Oxyspirura petrowi as a Possible Cause of Decline in the Threatened Lesser Prairie-Chicken (Tympanuchus pallidicinctus)

Abstract

Lesser prairie-chickens (Tympanuchus pallidicinctus) have been declining range wide since the early 1900's despite efforts to establish conservation and improve their habitat. In early 2014, the lesser prairie-chicken was listed as a threatened species under the U.S Endangered Species Act and the need to find out why they are declining is more important than ever. Nine hunter shot lesser prairie-chickens were donated and sampled for the presence or absence of the eyeworm Oxyspirura petrowi, a known parasite that can cause damage to the eye of its host, and common environmental contaminants. Eyeworm infection was found in 7 of 9 birds (78% infection rate) with an infection range between 0–16 O. petrowi per bird. Breast, liver, and fat tissue samples from the lesser prairie-chickens were analyzed for the frequency of 20 organochlorine pesticides. Femurs and livers were also tested on these birds for metal contaminants. Pesticides were found in several samples above the detection limits but were still in the low ng/g range. Notable was the ubiquitous presence of endrin aldehyde across all tissues. One femur showed 5.66 µg/g of lead (Pb) but this is still relatively low. No liver samples had elevated mercury (Hg) above detection limits. The presence of these organochlorines is consistent with the historic use of pesticides in this region. With pesticide and metals found in such low levels and parasitic nematode infections at rather high levels, it is recommended that these parasites be further evaluated as a contributing factor to the decline of the lesser prairie-chicken.

A Quantitative PCR Protocol for Detection of Oxyspirura petrowi in Northern Bobwhites (Colinus virginianus)

“…Particularly, O . petrowi has been detected in high prevalences in northern bobwhites ( Colinus virginianus ) in western Texas [3], and lesser prairie chickens ( Tympanuchus pallidicinctus ) in southwestern Kansas [2,7]. Over the last century northern bobwhite and lesser prairie chicken populations have been going experiencing declines [8,9].…”

“…Over the last century northern bobwhite and lesser prairie chicken populations have been going experiencing declines [8,9]. The cause of these decline has been largely attributed to habitat loss, habitat fragmentation, and climatic variables [10–12] with the role of disease only recently being investigated [3,7]. …”

“Weight of evidence” as a tool for evaluating disease in wildlife: An example assessing parasitic infection in Northern bobwhite (Colinus virginianus)

“…Oxyspirura petrowi have also been documented in wild turkey ( Meleagris gallopavo ; Kubečka et al, 2018 ), songbirds ( Dunham and Kendall, 2014 ), lesser prairie-chickens ( Tympanuchus pallidicinctus ; Dunham et al, 2014b ), Gambel's ( Callipepla gambelii ), and scaled quail ( Callipepla squamata ) ( Dunham and Kendall, 2017 ), while A . pennula have been found in scaled quail ( Dunham et al, 2017a ) and wild turkey ( Hon et al, 1975 ).…”

Life-cycle of Oxyspirura petrowi (Spirurida: Thelaziidae), an eyeworm of the northern bobwhite quail (Colinus virginianus)

“…In the USA, it was first reported in Galliformes and Passeriformes in Michigan during 1937 [1]. Since then, it has been identified in numerous other species from these orders, including the lesser-prairie chicken ( Tympanuchus pallidicinctus ) [2], northern cardinal ( Cardinalis cardinalis ) [3], northern mockingbird ( Mimus polyglottos ), curve-billed thrasher ( Toxostoma curvirostre ) [4], Gambel’s quail ( Callipepla gambelii) [5], scaled quail ( Callipepla squamata ) and northern bobwhite quail ( Colinus virginianus ; hereafter, bobwhite) [6]. Oxyspirura petrowi has gained particular notoriety in the Rolling Plains Ecoregion of West Texas, as this area is reported to be the epicenter of infection [7].…”