Case Report

Surgical Management of Eye Worm in a Horse: A Case Report

Al Wasef1, Md. Torikul Islam2, Vijay Kumar Sah1, Nitol Chandra Das1, Uday Kumar Mohanta1*

1Department of Microbiology and Parasitology, Faculty of Animal Science and Veterinary Medicine, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh; 2Veterinary Surgeon, Upazila Livestock Office and Veterinary Hospital, Narail Sadar, Narail, Bangladesh.

Received | July 23, 2025; Accepted | August 11, 2025; Published | October 29, 2025

*Correspondence | Uday Kumar Mohanta, Department of Microbiology and Parasitology, Faculty of Animal Science and Veterinary Medicine, Sher-e-Bangla Agricultural University, Dhaka-1207, Bangladesh; Email: [email protected]

Citation | Al Wasef, Islam MT, Sah VK, Das NC, Mohanta UK (2025). Surgical management of eye worm in a horse: A case report. Res J. Vet. Pract. 13(4): 70-73.

DOI | https://dx.doi.org/10.17582/journal.rjvp/2025/13.4.70.73

ISSN | 2308-2798

Copyright: 2025 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

Equine setariosis is a common ocular parasitic disease that impairs vision in equines, mainly resulting from an ectopic infestation of Setaria digitata, S. equina, and S. marshalli (Buchoo et al., 2005). Setaria is a nematode in the order Spirurida and the family Setariidae. Adult worms freely inhabit the abdominal cavity of the definitive host, the horse and donkey. These parasites also show migratory behaviour into various organs such as the heart, lungs, spleen, kidney, uterus, oviduct, ovary, urinary bladder, and occasionally they can get into the central nervous system or the eyes in a deviant host, particularly in horses, sheep, and goat (Perumal et al., 2016). The main form of migration in infected horses is ocular migration (Radwan et al., 2016). In the Indian subcontinent, setariosis is most common in the summer and fall when mosquito vectors, primarily Anopheles peditaneniatus and Culex nilgiricus, are most prevalent (Kumar et al., 2011). Adult female worms shed microfilariae in the abdominal cavity of their hosts circulate in the blood, causing “microfilariosis” in cattle and buffaloes (Lumain et al., 2021). When mosquitoes feed on the blood of infected hosts, they become infected with microfilariae. The infected mosquitoes transmit these infective larvae to other susceptible hosts during the blood meal around the eyes, and the deposited infective larvae migrate into the anterior chamber of the eye (Rafee and Amarpal, 2016). The infected animal with ocular setariosis shows symptoms of constant lacrimation, photophobia, corneal opacity, conjunctivitis, retinal detachment, and reduced performance, which may even lead to blindness if the treatment is delayed (Verma et al., 2019). Although involvement of the eye is often unilateral, bilateral occurrences have sometimes been documented too (Shin et al., 2002). The most effective treatment for ocular setariosisis the surgical removal of the parasite (Tuntivanich et al., 2011). Hence, the objective of this report was the successful surgical removal of the Setaria sp. from the eye of the mare.

Case history and clinical observation

A six-year-old mare weighing 250 kg was referred to the Upazila Veterinary Hospital, Narail District, Bangladesh, with continuous ocular discharge, photophobia, poor vision, and corneal opacity. The owner reported that the mare used to rub the right eye against the surrounding wall with no previous deworming history for a year. The temperature, pulse, and respiration rates of the mare were normal, but there was a gradual decrease in appetite. Clinical observation of the eye revealed a watery, thread-like worm of about 2 cm in length moving in a swirling motion in aqueous humour (Figure 1A). The Setaria sp. was identified based on morphological characteristics, including the ventral projection, dorsal projection, and lateral lips at the anterior end (Figure 1D), and a smooth knob at the posterior end (Figure 1E). Therefore, the condition was diagnosed as ocular setariosis due to the detection of Setaria sp. inside the anterior chamber of the eye of the mare. The mare was handled following the ethics and guidelines of the Upazila Veterinary Hospital.

TREATMENT AND DISCUSSION

At first, the mare was properly restrained, and then the supraorbital and auriculopalpebral nerves were blocked by administering 2% Lignocaine hydrochloride @ 10 ml, (G-Lidocaine®, Gonoshasthaya, Bangladesh) to the standing horse. After trimming the eyelashes of the affected eye, an antiseptic solution was applied around the eye, and the eyelid was retracted. The worm was expelled using a clear corneal stab with a scalpel with blade no. 11 at the 6 O’clock position. Then, the worm was flushed out along with the outflow of the aqueous humour (Figure 1B). After washing the collected sample with normal saline, the detailed morphological characteristics were examined under a light microscope, using lactophenol (Figure 1D and E). Following surgery, systemic antibiotic, Ceftriaxone @ 10mg/kg bwt (Triject Vet®, SK+F, Bangladesh), NSAID, Flunixin meglumine @ 1.1 mg/kg bwt (Meglunix Vet®, Popular, Bangladesh), and antihistamine, Promethazine hydrochloride @ 1 mg/kg bwt (Dellergen Vet®, Renata, Bangladesh), were administered intramuscularly (IM) for five days. Moreover, eye drop, a combination of Ciprofloxacin and dexamethasone (Civodex®, Popular, Bangladesh) was applied intraocularly 3-4 drops thrice a day till recovery. Additionally, Fenbendazole @ 5 mg/kg bwt (Fenazol®, Acme, Bangladesh) was administered for deworming after 7 days of surgery. Gradually, the corneal opacity disappeared, and the vision was restored within 30 days of surgery (Figure 1C). The vision restoration was assessed by animal’s reaction to the visual stimuli and the pupillary light reflex (PLR).

Adult worms of Setaria sp. are typically found in the peritoneal cavity of cattle and buffaloes. Heterotrophic parasitism of adult Setaria sp. worms from the peritoneum to the aqueous humor of affected animals causes injury to the cornea, leading to corneal opacity. Similar adverse effects of ocular setariosis in equines have been documented by Gangwar et al. (2008). Delayed treatment of ocular setariosis may lead to blindness (Buchoo et al., 2005). Despite both medical (Muhammad and Saqib, 2007) and surgical intervention (Buchoo et al., 2005) having been preferred for equine ocular setariosis. However, the best treatment is surgical removal of the eyeworm from the horse (Patil et al., 2016; Tuntivanich et al., 2011). Surgical intervention has a higher potential for rapid and effective treatment, which can be performed under general anesthesia or regional nerve blocks with or without sedation (Patil et al., 2012). Medical treatment has been less effective due to the slow absorption of dead parasites and the resultant antigenicity, leading to uveitis (Lavach, 1990). It took at least 15 days for the worm in the eye to die off following the administration of ivermectin (Muhammad and Saqib, 2007). Several case reports are available on different surgical techniques for worm removal, either by aspiration or incision. In this study, we have successfully performed corneal incision techniques using a corneal stab with a scalpel with blade no. 11 at the 6 o’clock position, which differs from a few of the previous studies (Kalpravidh et al., 1992), in which a stab incision was done at the 10-2 O’clock position of the eyeball.

CONCLUSION

Equine ocular setariosis is a condition that impairs vision in horses. Prompt diagnosis and treatment are key to a favourable outcome. Corneal incision technique using a corneal stab with a scalpel with blade no. 11 at the 6 O’clock position was proven to be an effective intervention for the removal of eyeworm from the mare. The removed worm was diagnosed as Setaria sp. Gradually, the corneal opacity disappeared following the surgery, and the vision was restored within 30 days of surgery.

ACKNOWLEDGEMENT

The authors are grateful to Upazila Livestock Officer (ULO), Upazila Livestock Office and Veterinary Hospital, Narail Sadar, Narail, Bangladesh, for their support during the study.

 

NOVELTY STATEMENT

This study highlighted the surgical removal of setariosis from the eyeball of a horse.

AUTHOR’S CONTRIBUTION

Al Wasef performed surgery, wrote the manuscript, and edited the manuscript. Md. Torikul Islam performed surgery and treated the mare. Vijay Kumar Sah and Nitol Chandra Das wrote the manuscript. Uday Kumar Mohanta supervised, reviewed the manuscript.

All authors checked and confirmed the last edition of the submitted manuscript.

Generative AI and AI-assisted technology statement

The authors declare that no generative AI or AI-assisted technologies were used in the preparation of this manuscript.

Conflict of interest

The authors have declared no conflict of interest.

REFERENCES

Buchoo BA, Pandit BA, Shahardar RA, Parrah JD, Darzl MM (2005). Surgical management and prevalence of ocular filariasis in equines. Indian Vet. J., 82(1): 81–82. https://www.researchgate.net/publication/294449931

Gangwar A, Devi S, Singh H, Singh A (2008). Ocular filariasis in equines. Indian Vet. J., 85(5): 547–548. https://www.researchgate.net/publication/285690813

Kalpravidh M, Bramasa A, Kalpravidh C (1992). Surgical removal of intraocular parasites from the anterior chambers of the horse eyes. Thai J. Vet. Med., 22: 13-20.

Kumar M, Monsang SW, Pawde AM, Singh SK, Madhu DN, Zama MMS (2011). Post-surgical healing effects of placentrex in equine (Equus cabalus) ocular setariosis: A review of 22 cases. Indian J. Field Vet.., 6(4): 71-73.

Lavach JD (1990). Parasitic diseases. In: Large animal ophthalmology. Vol 1. Philadelphia, Mosby, USA. pp. 260-263.

Lumain JPLM, Moncada NPD, Bagot MA (2021). Setaria from the peritoneal cavity of slaughtered cattle in Leyte, Philippines. Philipp. J. Vet. Med., 58(2): 219-223. https://ovcre.uplb.edu.ph/journals-uplb/index.php/PJVM/article/view/649

Muhammad G, Saqib M (2007). Successful treatment of ocular equine microfilariasis (Setaria species) with ivermectin. Vet. Rec., 160(1): 25. https://doi.org/10.1136/vr.160.1.25

Patil D, Kelawala D, Parikh P, Sheth M, Sini K, Parmar J (2016). Surgical management of ocular setariasis in horses. Indian J. Vet. Surg., 37(1): 44–47. https://www.researchgate.net/publication/310831652

Patil D, Parikh P, Joy N, Jhala S, Dar MUD, Tiwari D (2012). Equine eye worm: A review of 50 cases. Indian J. Vet. Surg., 33(1): 61–62. https://www.researchgate.net/publication/271387591

Perumal ANI, Gunawardene YINS, Dassanayake RS (2016). Setaria digitata in advancing our knowledge of human lymphatic filariasis. J. Helminthol., 90(2): 129-138. https://doi.org/10.1017/S0022149X15000309

Radwan AM, Ahmed NE, Elakabawy LM, Ramadan MY, Elmadawy RS (2016). Prevalence and pathogenesis of some filarial nematodes infecting donkeys in Egypt. Vet. World, 9(1): 888-892. https://doi.org/10.14202/vetworld.2016.888-892

Rafee MA, Amarpal A (2016). Equine Ocular Setariasis and its management. J. Exp. Biol. Agric. Sci., 4: 139-143. https://doi.org/10.18006/2016.4(Spl-4-EHIDZ).S139.S143

Shin SS, Cho KO, Wee SH (2002). Ocular infection of cattle with Setaria digitata. J. Vet. Med. Sci., 64(1): 7-10. https://doi.org/10.1292/jvms.64.7

Tuntivanich N, Tiawsirisup S, Tuntivanich P (2011). Success of anterior chamber paracentesis as a treatment for ocular setariasis in equine eye: Case report. J. Equine Vet. Sci., 31(1): 8–12. https://doi.org/10.1016/j.jevs.2010.11.017

Verma NK, Raghuvanshi PD, Gautam D, Saxena AC, Kinjavdekar P, Pawde AM (2019). Surgical management of equine ocular setariosis. Indian J. Vet. Surg., 40(1): 62-63. https://www.researchgate.net/publication/333603821