Parasitology Research (2018) 117:819–823 https://doi.org/10.1007/s00436-018-5756-3 ORIGINAL PAPER Molecular detection of Oxyspirura larvae in arthropod intermediate hosts Sadia Almas1 & Anna G. Gibson1 & Steven M. Presley1 Received: 8 September 2017 /Accepted: 8 January 2018 /Published online: 25 January 2018 # The Author(s) 2018. This article is an open access publication Abstract To determine potential intermediate hosts of Oxyspirura petrowi, a common nematode eyeworm of wild gallinaceous birds, various arthropod species including red harvester ants, beetles, wood cockroaches, crickets, grasshoppers, katydids, and desert termites were screened for the presence of O. petrowi using specific polymerase chain reaction (PCR) primers targeting the internal transcribed spacer 2 region (ITS2) of the eyeworm ribosomal deoxyribonucleic acid (rDNA). This is the first study to investigate the intermediate hosts of O. petrowi utilizing molecular techniques. We determined 38% (13/34) of the cockroaches, 27% (3/11) of the crickets, and 23% (68/289) of the grasshoppers which were positive for O. petrowi. Identifying potential intermediate hosts of O. petrowi is essential to better understanding the epizoology of the eyeworm’s transmission mechanics and to controlling infections in wild gallinaceous birds. Keywords Oxyspirura petrowi . Intermediate hosts . Galliformes . Parasitic nematodes . Bobwhite quail . Grasshopper . Cockroach Introduction reported an O. petrowi prevalence of 56% in scaled quail (Callipepla squamata) surveyed in Texas (Landgrebe et al. The long-term, and recently (2011–2013) more rapid, decline 2007). Oxyspirura petrowi is widely geographically dis- of northern bobwhite (Colinus virginianus) numbers in the tributed and occurs in a wide range of definitive hosts. Rolling Plains ecoregion of Texas and Oklahoma was inves- Oxyspirura petrowi commonly infects wild birds of the tigated to determine factors that may be influencing their order Galliformes in North America and was first reported abundance (Fig. 1). During this study, 348 northern bobwhites in Michigan, USA in 1931, and has been reported infect- were screened for different pathogens. Infection rates of ing ruffed grouse (Bonasa umbellus), greater prairie chick- 41.4% of bobwhite collected from individual sites in the en (Tympanuchus cupido), ring-necked pheasant Rolling Plains ecoregion by the parasitic nematode eyeworm (Phasianus colchicus), and sharp-tailed grouse Oxyspirura petrowi (Spirurida:Thelaziidae) was reported (Tympanuchus phasianellus) (Cram 1937; Mcclure 1949; (Dunham et al. 2016). Pence 1972; Pence 1975; Pence et al. 1980). Oxyspirura Typically, these eyeworms are observed on the corneal spp. are spiruroid nematodes and include approximately 70 surface under the nictitating membrane, in nasolacrimal known species, three of which (O. mansoni, O. petrowi, ducts and in conjunctival sacs, causing cellular damage and O. pusillae) have been reported in North America to these tissues; however, their effect on the survivability (Pence and Sell 1979). Typically these eyeworms are ob- of their hosts is unknown. (Rodriguez-Tovar et al. 2008; served on the corneal surface under the nictitating mem- Bruno et al. 2015). Previously, Landgrebe et al. 2007 brane, in nasolacrimal ducts, and in conjunctival sacs, causing cellular damage to these tissues (Rodriguez-Tovar et al. 2008; Bruno et al. 2015). The life cycle of O. petrowi is not well described, but it is * Steven M. Presley assumed to be similar to that of O. mansoni, a common [email protected] eyeworm of poultry. Oxyspirura mansoni requires an interme- 1 The Institute of Environmental and Human Health, Texas Tech diate host such as a cockroach (Blattodea) to facilitate trans- University, Box 41163, Lubbock, TX 79409-1163, USA mission to its definitive host. The eyeworm life cycle involves 820 Parasitol Res (2018) 117:819–823 was chosen as target for developing species-specific primers. Materials and methods This study was conducted in accordance with ethical stan- dards and approved animal care and use protocols (Texas Tech University, Institutional Animal Care and Use Committee protocol No. 11049–070). Eyeworms were col- lected from the eyes of euthanized bobwhite and stored in 70% ethanol, then identified initially on the basis of morpho- logical characteristics using a Nikon microscope (TE 2000 U) at 400× and 1000× magnification, after which they were sub- mitted to the U.S. National Parasite Collection for confirma- tion (USNPC 106874). Deoxyribonucleic acid (DNA) was Fig. 1 Map of the geographic area designated as the Rolling Plains extractedfromsinglenematodeusingtheDNeasyBlood& ecoregion of Texas and Oklahoma, USA. Tissue Kit (QIAGEN, Maryland, USA) according to the man- ufacturer’s instructions. The internal transcribed spacer (ITS) region was amplified using the forward primer SPIR 18 and the reverse primer 28S/408R/20 (Ivanova et al. 2007; 50–100 days of stadial progression in the intermediate host, Makouloutou et al. 2013).The PCR product, ~ 1200 base pair and 48 days in the definitive host (e.g., chicken) (Mcclure (bp), was excised and cloned into JM109 competent cells 1949). The importance of the intermediate hosts in the life (Promega Corp., Wisconsin, USA.) according to the manufac- cycle of O. mansoni was confirmed after futile attempts to turer’s instructions. Plasmids were extracted and submitted for directly infect chickens one to another using embryonated genetic sequencing to the University of Maine DNA nematode eggs or first-stage eyeworm larvae (Cram 1937). Sequencing Facility (Orono, Maine, USA). Based on the se- Observational reports suggest various insects such as flies quence obtained, the primers OP3,5′ TGTTGTGGAGCAGT and grasshoppers may serve as intermediate hosts for TAAAATCC-3′,andOP4,5′AACGTTATTGTTGCCATATG O. petrowi (Mcclure 1949). CT-3′, were designed to amplify a 197-bp region of ITS2. ThehighprevalenceofO. petrowi reported in bob- To ensure specificity, the intraspecific variation in the ITS white and other wild game birds, and the limited knowl- region of this genus was investigated. The sequence of the edge of its transmission mechanisms, necessitate the de- ITS1 region of O. petrowi was aligned with the corresponding velopment of a sensitive, specific, and reliable method region of O. conjunctivalis, which was the only Oxyspirura to screen different arthropods for the presence of spp. with a sequence available in the National Center for eyeworms. Typically, detection of nematodes in insects Biotechnology Information (NCBI) database (accession num- involves dissecting the insect and recovering nematodes, ber EF417873). Primers were synthesized by Integrated DNA then identifying different specimens based on morpho- Technologies, Inc. (IDT) (Iowa, USA). PCR conditions in- logical characteristics. This process can be time con- cluded a 2-minute denaturation step at 94 °C, followed by suming and its accuracy is highly dependent on the 35 cycles of 94 °C for 30 s, 55 °C for 30 s, and 72 °C for experience of the investigator, as it may be difficult to 1 min, with a final elongation step at 72 °C for 10 min. The distinguish between different species of nematodes, es- specificity of primers was verified using the Basic Local pecially the larval stages (Perera et al. 2013). We report Alignment Search Tool (BLAST) against the NCBI database. here the development of a polymerase chain reaction To further confirm the specificity of the primers, DNA isolated (PCR)-based technique for the detection of any from the nematode Strongyloides stercoralis was used as a O. petrowi life stages in arthropods, for the purpose of negative control. To determine the sensitivity of the primers, learning more about its potential intermediate hosts. PCR was performed with 100 ng–1 pg of template DNA from This is the first study to identify a range of potential O. petrowi. arthropod intermediate hosts of O. petrowi based on Arthropod specimens were collected during biannual trap- molecular techniques. Due to their rapid evolution, high ping of quail during the months of August and October (2012 variation in their length and nucleotide contents between and 2013) from several ranches across the Rolling Plains closely related species, the internal transcribed spacer ecoregion of Texas and western Oklahoma. Various insects, (ITS) region of the ribosomal nucleic acid (rRNA) gene including red harvester ants (Order: Hymenoptera), beetles Parasitol Res (2018) 117:819–823 821 (Order: Coleoptera), wood cockroaches (Order: Blattodea), were determined to contain DNA of O. petrowi. All of the red crickets (Order: Orthoptera), grasshoppers (Order: ants, beetles, katydids, and termites were determined to be Orthoptera), katydids (Order: Orthoptera), and desert termites negative for the eyeworm. Out of the 15 different species of (Order: Isoptera) were collected in close proximity to bob- grasshoppers screened for the presence of O. petrowi, six dif- white quail trapping sites using baited petri plates, insect ferent species of grasshoppers including Melanoplus sweep nets, commercially available pheromone traps, and differentialis, Melanoplus femurrubrum, Trimerotropis bread- and beer-baited traps as described by Pechal and others pallidipennis, Melanoplus ponderosus, Opeia obscura, and (Pechal et al. 2007). Collected specimens were preserved in Hippiscus ocelote were positive for O. petrowi. Other than 70% ethanol and stored at − 20 °C until analysis. Arthropods these grasshopper species, Texas field cricket