ArticlePDF Available

Avian and Emerging Human Oxyspirura Species Compared by Morphology, Pathogenicity, Intermediate Host, and Sequence Homology



Based on sequence homology and phylogenetic tree results, the first report of eyeworm Oxyspirura species larvae has been confirmed in a human patient from Vietnam. However, important information related to Oxyspirura larvae was not presented in the case study. This comment provides a more detailed comparison of the Oxyspirura larvae found in the human case study to the avian eyeworm Oxyspirura petrowi.
Avian and Emerging Human Oxyspirura Species
Compared by Morphology, Pathogenicity, Intermediate
Host, and Sequence Homology
Authors: Kalyanasundaram, Aravindan, Bastille, Maya O., Lukashow-
Moore, Shannon P., and Kendall, Ronald J.
Source: Journal of Parasitology, 106(4) : 623-624
Published By: American Society of Parasitologists
BioOne Complete ( is a full-text database of 200 subscribed and open-access titles
in the biological, ecological, and environmental sciences published by nonprofit societies, associations,
museums, institutions, and presses.
Your use of this PDF, the BioOne Complete website, and all posted and associated content indicates your
acceptance of BioOne’s Terms of Use, available at
Usage of BioOne Complete content is strictly limited to personal, educational, and non - commercial use.
Commercial inquiries or rights and permissions requests should be directed to the individual publisher as
copyright holder.
BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit
publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to
critical research.
Downloaded From: on 19 Feb 2021
Terms of Use:Access provided by Texas Tech University
Published 2 October 2020
DOI: 10.1645/20-106
Contents and archives available through or
Journal of Parasitology
journal homepage:
Aravindan Kalyanasundaram, Maya O. Bastille, Shannon P. Lukashow-Moore, and Ronald J. Kendall
The Wildlife Toxicology Laboratory, Texas Tech University, Lubbock, Texas 79409-3290.
Correspondence should be sent to Ronald J. Kendall ( at:
Based on sequence homology and phylogenetic tree results, the first report of eyeworm Oxyspirura
species larvae has been confirmed in a human patient from Vietnam. However, important
information related to Oxyspirura larvae was not presented in the case study. This comment provides
a more detailed comparison of the Oxyspirura larvae found in the human case study to the avian
eyeworm Oxyspirura petrowi.
We read with interest the recent article reporting the first
documented case of human infection with Oxyspirura species
larvae (Dung et al., 2020). We published the sequence of the avian
eyeworm Oxyspirura petrowi (accession no. LC316613) that was
found to have high similarity (96.6%) in sequence analysis, as well
as high bootstrap value (93%) in the phylogenetic tree, to the 18S
rRNA sequence of the human patient in Vietnam (Kalyanasun-
daram et al., 2018; Dung et al., 2020). With the above noteworthy
similarity, we provide additional evidence comparing morpholo-
gy, pathogenicity, and information about the intermediate host to
support that the Oxyspirura species of the human case is very
closely related to the avian O. petrowi.
Morphological observations of the recent case study were
similar to third-stage O. petrowi recovered from experimentally
infected house crickets (Acheta domesticus). The Oxyspirura sp.
matched in terms of larvae length (~700–850 lm), nerve ring
distance, papilla (anterior end), and buccal cavity (clear with 6
lobes) and matured anus (Kalyanasundaram et al., 2019b; Dung
et al., 2020), indicating the larvae specimen found in the human
patient was in its third developmental stage. Additionally, we
found embryonated eggs in the fecal samples of Northern
bobwhites (Colinus virginianus), which was not detected in the
human case, indicating humans may be a paratenic host to
Oxyspirura sp. larvae. Paratenic hosts that contain high
accumulations of the parasite in the larval stage without showing
further development in the life cycle are most likely incidental
transporters rather than serving as the parasite’s intermediate
host. This stage was observed in the human case of Oxyspirura
Pathogenicity findings revealed disseminated pruritic erythema
in the skin of the infected humans (Dung et al., 2020). Northern
bobwhites infected with O. petrowi also showed signs of
inflammation, along with distinct petechial hemorrhaging, corneal
scarring, conjunctivitis, and keratitis was observed in the lacrimal
ducts, eyelid, nictitating membrane, and in the conjunctival sac
(Dunham et al., 2014; Bruno et al., 2015). Our recent O. petrowi
glycoprotein challenge study using host cytokines showed a
measurable immune reaction in experimental bobwhites (Kalya-
nasundaram et al., 2019a). Although the localization of infection
from the Oxyspirura species differed between human and avian
subjects, the parasitic infection ultimately induced a similar lesion
and inflammatory response in both cases.
In the Vietnam case study, the patient and his neighbors
reported that had regularly consumed grasshoppers and crickets
as a part of their diet for more than a year (Dung et al., 2020).
Our recent studies (Kistler et al., 2016; Kalyanasundaram et al.,
2018) experimentally demonstrated that the grasshopper (Bra-
chystola magna) and house cricket (A. domesticus) serve as
intermediate hosts for O. petrowi, indicating that L3 infective
larvae are transmitted to the avian definitive host when ingested.
A recent study (Gałecki and Soko
´ł, 2019), evaluating the
relationship of regularly consumed insects and their role in the
transmission of parasitic diseases to humans and animals, further
supports the theory that frequently consumed insects may serve as
the most significant vector for these parasites. The authors from
the Vietnam study (Dung et al., 2020) also stated that further
investigation of maturated Oxyspirura in poultry in the patient’s
community was needed. However, this might be counterintuitive,
Journal of Parasitology 2020 106(5) 623–624
ÓAmerican Society of Parasitologists 2020
Downloaded From: on 19 Feb 2021
Terms of Use:Access provided by Texas Tech University
as previous evidence reported the chicken eyeworm O. mansoni
transmits through its single intermediate host, the burrowing
cockroach Pycnoscelus surinamensis (Schwabe, 1951).
In conclusion, the similarities in sequence homology, morphol-
ogy, pathogenicity, and intermediate hosts indicate the Oxyspi-
rura sp. found in the human patient as an emerging pathogen is
very closely related to O. petrowi, and further research is
necessary to determine the extent of the relation by species-level
2015. Pathological response of northern bobwhites to
Oxyspirura petrowi infections. Journal of Parasitology 101:
N. DOANH. 2020. Pruritic cutaneous nematodiasis caused by
avian eyeworm Oxyspirura larvae,Vietnam.Emerging
Infectious Diseases 4: 786–788.
R. J. KENDALL. 2014. Evidence of an Oxyspirura petrowi
epizootic in northern Bobwhites (Colinus virginianus), Texas,
USA. Journal of Wildlife Disease 50: 552–588.
´ł. 2019. Parasitological evaluation of
edible insects and their role in the transmission of parasitic
diseases to humans and animals. PLoS ONE 7: e0219303.
AND R. J. KENDALL. 2018. Phylogenetic analysis of eyeworm
(Oxyspirura petrowi) in northern bobwhite (Colinus virgin-
ianus) based on the nuclear 18S rDNA and mitochondrial
cytochrome oxidase 1 gene (COX1). Parasitology Open 4: e7.
HENRY,M.Z.BRYM,AND R. J. KENDALL. 2019a. Quantitative
analysis of Northern bobwhite (Colinus virginianus) cytokines
and TLR expression to eyeworm (Oxyspirura petrowi) and
caecal worm (Aulonocephalus pennula) glycoproteins. Parasi-
tology Research 118: 2909–2918.
J. KENDALL. 2019b. Life-cycle of Oxyspirura petrowi (Spiru-
rida: Thelaziidae), an eyeworm of the northern bobwhite
quail (Colinus virginianus). Parasites & Vectors 2: 555. doi:10.
PARLOS,ET AL. 2016. Plains lubber grasshopper (Brachystola
magna) as a potential intermediate host for Oxyspirura
petrowi in northern bobwhites (Colinus virginianus). Parasi-
tology Open 2: e7. doi: 10.1017/pao.2016.5.
SCHWABE, C. W. 1951. Studies on Oxyspirura mansoni, the tropical
eyeworm of poultry. II. Life history. Pacific Science 5: 18–35.
Downloaded From: on 19 Feb 2021
Terms of Use:Access provided by Texas Tech University
In the present study, a novel series of side chain-modified quinoline β-enaminones were synthesized in good-to-excellent yields. The structures of all the synthesized compounds have been established with the help of spectral and analytical data and also by X-ray crystallography. All the compounds were screened for their potential in vitro anti-malarial activity against chloroquine resistant strain K1 and chloroquine sensitive strain 3D7. The compounds were also evaluated for their in vitro microfilaricidal and adulticidal effect against B. malayi microfilariae and adult worms using ivermectin as positive control. The cytotoxicity of the compounds was checked against Vero cell line and all the compounds were found to be non-toxic. The compounds showed low antimalarial activities against both the plasmodial strains compared to the standard drug chloroquine. However, four of the evaluated compounds have shown significant in vitro adulticidal activity and their percentage inhibition were found to be 68, 55, 64, and 66, respectively. Two of these were selected for further preliminary in vivo activity studies.Graphical abstract
Full-text available
A 41-year-old man from Son La Province, Vietnam, sought care for disseminated prurigo-like skin lesions from which nematode larvae were emerging. We morphologically and molecularly identified the larvae as Oxyspirura sp. Our findings confirm this nematode species as a zoonotic pathogen for emerging disease.
Full-text available
Background: Oxyspirura petrowi (Spirurida: Thelaziidae), a heteroxenous nematode of birds across the USA, may play a role in the decline of the northern bobwhite (Colinus virginianus) in the Rolling Plains Ecoregion of West Texas. Previous molecular studies suggest that crickets, grasshoppers and cockroaches serve as potential intermediate hosts of O. petrowi, although a complete study on the life-cycle of this nematode has not been conducted thus far. Conse-quently, this study aims to improve our understanding of the O. petrowi life-cycle by experimentally infecting house crickets (Acheta domesticus) with O. petrowi eggs, feeding infected crickets to bobwhite and assessing the life-cycle of this nematode in both the definitive and intermediate hosts.Methods: Oxyspirura petrowi eggs were collected from gravid worms recovered from wild bobwhite and fed to house crickets. The development of O. petrowi within crickets was monitored by dissection of crickets at specified intervals. When infective larvae were found inside crickets, parasite-free pen-raised bobwhite were fed four infected crickets each. The maturation of O. petrowi in bobwhite was monitored through fecal floats and bobwhite necropsies at specified intervals.Results: In this study, we were able to infect both crickets (n = 45) and bobwhite (n = 25) with O. petrowi at a rate of 96%. We successfully replicated and monitored the complete O. petrowi life-cycle in vivo, recovering embryonated O. petrowi eggs from the feces of bobwhite 51 days after consumption of infected crickets. All life-cycle stages of O. petrowi were confirmed in both the house cricket and the bobwhite using morphological and molecular techniques.Conclusions: This study provides a better understanding of the infection mechanism and life-cycle of O. petrowi by tracking the developmental progress within both the intermediate and definitive host. To our knowledge, this study is the first to fully monitor the complete life-cycle of O. petrowi and may allow for better estimates into the potential for future epizootics of O. petrowi in bobwhite. Finally, this study provides a model for experimental infection that may be used in research examining the effects of O. petrowi infection in bobwhite. (PDF) Life-cycle of Oxyspirura petrowi (Spirurida: Thelaziidae), an eyeworm of the northern bobwhite quail (Colinus virginianus). Available from: [accessed Nov 22 2019].
Full-text available
Helminth parasites have been a popular research topic due to their global prevalence and adverse effects on livestock and game species. The Northern bobwhite (Colinus virginianus), a popular game bird in the USA, is one species subject to helminth infection and has been experiencing a decline of > 4% annually over recent decades. In the Rolling Plains Ecoregion of Texas, the eyeworm (Oxyspirura petrowi) and caecal worm (Aulonocephalus pennula) helminths are found to be highly prevalent in bobwhite. While there have been increasing studies on the prevalence, pathology, and phylogeny of the eyeworm and caecal worm, there is still a need to investigate the bobwhite immune response to infection. This study utilizes previously sequenced bobwhite cytokines and toll-like receptors to develop and optimize qPCR primers and measure gene expression in bobwhite intramuscularly challenged with eyeworm and caecal worm glycoproteins. For the challenge experiments, separate treatments of eyeworm and caecal worm glycoproteins were administered to bobwhite on day 1 and day 21. Measurements of primary and secondary immune responses were taken at day 7 and day 28, respectively. Using the successfully optimized qPCR primers for TLR7, IL1β, IL6, IFNα, IFNγ, IL10, and β-actin, the gene expression analysis from the challenge experiments revealed that there was a measurable immune reaction in bobwhite in response to the intramuscular challenge of eyeworm and caecal worm glycoproteins.
Full-text available
From 1 January 2018 came into force Regulation (EU) 2015/2238 of the European Parliament and of the Council of 25 November 2015, introducing the concept of "novel foods", including insects and their parts. One of the most commonly used species of insects are: mealworms (Tenebrio molitor), house crickets (Acheta domesticus), cockroaches (Blattodea) and migratory locusts (Locusta migrans). In this context, the unfathomable issue is the role of edible insects in transmitting parasitic diseases that can cause significant losses in their breeding and may pose a threat to humans and animals. The aim of this study was to identify and evaluate the developmental forms of parasites colonizing edible insects in household farms and pet stores in Central Europe and to determine the potential risk of parasitic infections for humans and animals. The experimental material comprised samples of live insects (imagines) from 300 household farms and pet stores, including 75 mealworm farms, 75 house cricket farms, 75 Madagascar hissing cockroach farms and 75 migrating locust farms. Parasites were detected in 244 (81.33%) out of 300 (100%) examined insect farms. In 206 (68.67%) of the cases, the identified parasites were pathogenic for insects only; in 106 (35.33%) cases, parasites were potentially parasitic for animals; and in 91 (30.33%) cases, parasites were potentially pathogenic for humans. Edible insects are an underestimated reservoir of human and animal parasites. Our research indicates the important role of these insects in the epidemiology of parasites pathogenic to vertebrates. Conducted parasitological examination suggests that edible insects may be the most important parasite vector for domestic insectivorous animals. According to our studies the future research should focus on the need for constant monitoring of studied insect farms for pathogens, thus increasing food and feed safety.
Full-text available
Oxyspirura petrowi is a heteroxenous nematode found in northern bobwhite ( Colinus virginianus ) of the Rolling Plains ecoregion of Texas. Despite its impact on this popular gamebird, genetic level studies on O. petrowi remain relatively unexplored. To accomplish this, we chose the previously studied nuclear rDNA 18S region as well as the mitochondrial COX1 gene region of O. petrowi to investigate phylogenetic relations between O. petrowi and other nematode species. In this study, we generate primers using multiple alignment and universal nematode primers to obtain a near-complete 18S and partial COX1 sequence of O. petrowi , respectively. Phylogenetic trees for O. petrowi ’s 18S and COX1 gene regions were constructed using the Maximum Likelihood and Maximum Parsimony method. A comparative analysis was done based on the nuclear and mitochondrial region similarities between O. petrowi and other nematode species that infect both humans and animals. Results revealed a close relation to the zoonotic eyeworm Thelazia callipaeda as well as a close relation with filarial super family (Filarioidea) such as the human eyeworm Loa loa and Dirofilaria repens eyeworm of dog and carnivores.
Full-text available
Plains Lubber Grasshopper (Brachystola magna) as a Potential Intermediate Host for Oxyspirura petrowi in Northern Bobwhites (Colinus virginianus) – CORRIGENDUM - Volume 2 - WHITNEY M. KISTLER, SABRINA HOCK, BEATRICE HERNOUT, EVAN BRAKE, NIKKI WILLIAMS, CARSON DOWNING, NICHOLAS R. DUNHAM, NAVEEN KUMAR, UDAY TURAGA, JULIE A. PARLOS, RONALD J. KENDALL
Full-text available
Oxyspirura petrowi is a heteroxenous parasitic nematode that has been reported in high prevalences from birds in the Order Galliformes experiencing population declines in the USA. There is a paucity of information regarding the natural history O. petrowi, including the life cycle and effects of infection on wild bird populations. In order to study the life cycle of this parasite, we collected plains lubber grasshoppers (Brachystola magna) from a field location in Mitchell County, Texas. We found third-stage larvae (L3) in 37.9% (66/174) B. magna. We determined that they were O. petrowi through morphological comparison of L3 from experimentally infected Acheta domesticus and by sequence analysis. Then, we showed that B. magna are a potential intermediate hosts for O. petrowi infections in northern bobwhites (Colinus virginianus) in a laboratory setting by experimental infection. We first detected shedding of eggs in feces using a fecal float technique 52 days post infection. In addition, we recovered 87 O. petrowi from experimentally infected northern bobwhites. Although we detected shedding in feces, recovery of eggs was low (>5 eggs/g). Future work is needed to understand shedding routes and shedding patterns of northern bobwhites infected with O. petrowi.
Full-text available
The effects of Oxyspirura petrowi infections in northern bobwhites (Colinus virginianus) are not well understood. While studies have reported O. petrowi infections, none have 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.
Full-text available
Abstract We captured 36 Northern Bobwhites (Colinus virginianus) in Mitchell County, Texas in June-September 2013, and examined them for the eyeworm Oxyspirura petrowi. We recovered 334 eyeworms from 28 of 29 adult bobwhites (97%); infections ranged from 1-40 worms and mean (±SD) abundance of 11.9±13.0. Three of seven juveniles were infected, and those infected had one eyeworm each. Prevalence of eyeworms was similar among months. However, mean abundance of eyeworms peaked in July and August (3.3±2.1, 13.5±15.0, and 16.9±15.5), and decreased in September (6.3±3.0). We suggest that several previous studies may underreport prevalence and abundance because in those studies only the eye surface and nictitating membrane were examined, and not eye-associated tissue, ducts, glands, or sinuses.