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The Northern Bobwhite ( Colinus virginianus ) has been steadily declining throughout much of its historic range for decades. The Rolling Plains ecoregion of Texas and western Oklahoma, historically rich with wild Northern Bobwhites and one of the last remaining quail strongholds, also has a declining population. During August and October in 2011-13, 348 Northern Bobwhites from the Rolling Plains were examined for eyeworms (Oxyspirura petrowi). Of these 348 Northern Bobwhites, 144 (41.4%) were infected with 1,018 total eyeworms. Eyeworm abundance (mean±SE) was 2.9±0.4 (range 0-64), with an intensity (mean±SE) of 7.1±0.6. Eyeworm prevalence was significantly higher in adult Northern Bobwhites (58.7%) than in juveniles (35.4%). Recent research suggests that eyeworms have the potential to cause cellular tissue damage to the eye, but it is unknown how these worms affect host survivability. This study further expands the regional distribution of O. petrowi in Northern Bobwhites in the Rolling Plains ecoregion and assesses the prevalence and abundance of infection across host age, host sex, and year. Further research is warranted on the life history of O. petrowi and assessing the impacts of eyeworms on their definitive host at individual and population levels.

The effects of Oxyspirura petrowi infections in northern bobwhites ( Colinus virginianus ) are not well understood. While studies have reported O. petrowi infections, none has histopathologically examined the eye surface and intraorbital glands to assess cellular-level impacts associated with infection. This study is the first to document the histopathology associated with O. petrowi infections. Oxyspirura petrowi occurred on the eye surface as well as in the conjunctiva, lacrimal ducts, lacrimal glands, and Harderian glands. Histopathology showed infections of O. petrowi caused cellular damage to these tissues, scarring and interstitial keratitis of the cornea, and acinar atrophy of the Harderian gland.

Northern bobwhite ( Colinus virginianus ) have experienced a dramatic decline in West Texas over the last 3 yr, and investigations are underway to evaluate the role of parasites in this decline. One of the key parasites being investigated is the eyeworm (Oxyspirura petrowi). Live eyeworms were extracted from both live and dead northern bobwhites, and in vitro survival was tested using 10 liquid media. Eyeworms placed in an egg white and physiological saline solution lived for at least 36 days. Live O. petrowi placed into the eyes of uninfected pen-raised bobwhites were monitored for 21 days to demonstrate successful transfer. Eyeworm behavior during feeding, mating, and development were monitored. This study is important to research that requires "banking" of live O. petrowi from wild-captured definitive hosts for life history studies and assessing the impact of O. petrowi on host individuals.

Background: Oxyspirura petrowi appears to be emerging as a nematode parasite that could negatively impact Northern Bobwhite quail individuals and populations within Texas and other regions of the United States. Despite this eye worm's potential importance in the conservation of wild quail, little is known about the general biology and genome composition of O. petrowi. To fill the knowledge gap, we performed a small scale random genome sequence survey, sequenced its 18S rRNA and the intergenic region between the 18S and 28S rRNA genes, studied its phylogenetic affinity, and developed a PCR protocol for the detection of this eye worm., Results: We have generated ~240 kb of genome sequence data derived from 348 clones by a random genome survey of an O. petrowi genomic library. The eye worm genome is AT-rich (i.e., 62.2% AT-content), and contains a high number of microsatellite sequences. The discovered genes encode a wide-range of proteins including hypothetical proteins, enzymes, nematode-specific proteins. Phylogenetic analysis based on 18S rRNA sequences indicate that the Spiruroidea is paraphyletic, in which Oxyspirura and its closely related species are sisters to the filarial nematodes. We have also developed a PCR protocol based on the ITS2 sequence that allows sensitive and specific detection of eye worm DNA in feces. Using this newly developed protocol, we have determined that ~28% to 33% of the fecal samples collected from Northern Bobwhites and Scaled Quail in Texas in the spring of 2013 are O. petrowi positive., Conclusions: The O. petrowi genome is rich in microsatellite sequences that may be used in future genotyping and molecular fingerprinting analysis. This eye worm is evolutionarily close to the filarial nematodes, implying that therapeutic strategies for filariasis such as Loa loa would be referential in developing treatments for the Thelazoidea parasites. Our qPCR-based survey has confirmed that O. petrowi infection is of potential concern to quail managers in Texas.