Molecular identification of Physaloptera sp. from wild northern bobwhite (Colinus virginianus) in the Rolling Plains ecoregion of Texas

Physaloptera spp. are common nematodes found in the stomach and muscles of mammals, reptiles, amphibians, and birds. Physaloptera spp. have a complicated life cycle with multiple definitive hosts, arthropod intermediate hosts, aberrant infections, and possible second intermediate hosts or paratenic hosts. For example, Physaloptera sp. larvae have been found within the tissues of wild northern bobwhite quail (Colinus virginianus), and it is suspected that quail may serve as paratenic or secondary hosts of these parasites. However, because it is not known what role quail play in the life cycle of Physaloptera spp. and descriptions of Physaloptera spp. larvae are limited, molecular tools may be beneficial when identifying these helminths. In this study, we generated primers using universal nematode primers and obtained a partial mitochondrial cytochrome oxidase 1 (COX 1) sequence. Morphological identification of Physaloptera sp. in bobwhite was confirmed via polymerase chain reaction (PCR), and a phylogenetic tree was constructed using the maximum likelihood method. BLAST analysis revealed a strong identity to other Physaloptera spp. and the phylogenetic tree placed all Physaloptera spp. in the same cluster. We also documented a marked increase in Physaloptera infections in bobwhite from 2017 to 2018, and the similarity of these parasites to Onchocerca volvulus and Wuchereria bancrofti may give insight into the increased prevalence we observed. This study demonstrates the usefulness of molecular techniques to confirm the identity of species that may lack adequate descriptions and provides new insight for the diagnosis and potentially overlooked significance of Physaloptera sp. infections of bobwhite in the Rolling Plains ecoregion of Texas.