Ophthalmomyiasis caused by the sheep bot fly Oestrus ovis in northern Iraq

Ophthalmomyiasis Externa and Importance of Risk Factors, Clinical Manifestations, and Diagnosis: Review of the Medical Literature

OBJECTIVE

This review aims to describe and compare the risk factors, clinical course, diagnosis, and parasitologic features of external ophthalmomyiasis. We also discuss the different preventive measures and the effect of global warming in a large case series reported from January 2000 to December 2022.

METHODS

We perform a literature review of reported cases of external ophthalmomyiasis to determine the clinical characteristics, therapeutic management, and information on the organisms that most commonly cause external ophthalmomyiasis.

RESULTS

A total of 312 cases of external ophthalmomyiasis were recorded. The most common causative organism was Oestrus ovis (Linnaeus) (Diptera: Oestridae), accounting for 72.1% of cases, followed by Dermatobia hominis (Linnaeus Jr. in Pallas, 1781) (Diptera: Oestridae) at 5.4%, Lucilia sericata (Meigen) (Diptera: Calliphoridae) at 0.96%, and Chrysomyia bezziana (Villeneuve) (Diptera: Calliphoridae) at 0.96%. Before experiencing symptoms, 43.6% of cases reported having direct contact with flies or being hit in the eye, 33% reported no associated risk factors, 9.3% reported living with sheep and goats, and 7.7% reported a history of foreign objects entering the eye. The most common symptoms for those affected by O. ovis were sudden onset, including a foreign body sensation and movement, redness, tearing, itching, swelling, irritation, photophobia, burning, and ocular secretion. In cases caused by D. hominis, symptoms included eyelid edema, pain, redness, itching, movement within the lesion, ocular irritation, and discharge. Regarding occupational or recreational activity, agriculture, and livestock had the highest incidence, followed by trades and technical activities, being a student, and having traveled to an endemic region for work or recreation.

CONCLUSION

Patients with red eyes may suffer from external ophthalmomyiasis, which requires a thorough examination to diagnose and treat it early. Moreover, as the temperature increases due to climate change, it is essential to consider how this will affect the spread of different pathogens.

Ophthalmomyiasis externa caused by Oestrus ovis

This report describes the case of a woman in her early 20s who presented with a 3-day history of mobile foreign bodies and watering from her right eye. She had recently returned from vacation on a Greek island and presented to an ophthalmology unit in London, UK. A sample taken demonstrated Oestrus ovis infestation and confirmed the diagnosis of ophthalmomyiasis externa. She was treated with prophylactic topical antibiotics and subsequently made a full recovery. This was only the sixth presentation of O. ovis ophthalmomyiasis externa documented within the UK and the only case documented within the last 20 years. This is the fifth documented case found to have been transmitted within Greece.

External ophthalmomyiasis by Oestrus ovis in tourists visiting Italy. Report of three cases and a literature review

BACKGROUND

Oestrus ovis is a dipteran parasite responsible of myiasis in small ruminants and reported as the causative agent of myiasis in humans particularly in sheep farming areas. In recent years, several human cases had been reported without any previous history of exposure to livestock or visit to rural areas.

CASE PRESENTATION

We describe three clustered cases of ophthalmomyiasis externa in tourists in Sardinia and Sicily and discuss them in the light of the published literature. The patients presented ocular irritation, foreign body sensation, pain, redness, and lacrimation of the eyelids. After extraction, all the larvae were morphologically and molecularly confirmed as L1 instar of O. ovis larvae.

CONCLUSIONS

The present study points out the need to draw attention and awareness among the physicians, and to consider ophthalmomyiasis when consulted for conjunctivitis in the summer and spring seasons.

Rhinomyiasis by Oestrus ovis in a tourist returning from Corsica

In the Mediterranean basin, one of the most important agents of myiasis is Oestrus ovis Linnaeus 1758 (Diptera, Oestridae). Herein, we report a rare case of nasal myiasis with a secondary infection complication in a patient from northern Italy who had been visiting Corsica. A healthy, 39-year-old Italian woman spent 2 weeks of vacation in Corsica in June 2018. During her stay, she suddenly felt a foreign body inside her nose, followed by cough, pain, burning at the pharyngeal level, cephalalgia, and nasal congestion with secretions from the nostrils. The clinical examination showed a hyperemic and irritated mucosa and endoscopic examination of the patient's nose and right maxillary sinus revealed three tiny mobile larvae, morphologically and molecular identified as L1 instar larvae of Oestrus ovis. The patient's infestation was probably imported from Corsica, as Mediterranean islands are ideal geographical areas for the development of O. ovis, and the timing of infestation match with the period of O. ovis larviposition. Although rhinomyiasis is rare, it should be considered in people returning from abroad presenting with an acute-onset and foreign body sensation in the nose.

The global and regional prevalence of oestrosis in sheep and goats: a systematic review of articles and meta-analysis

Background

Oestrosis, caused by the larvae of Oestrus ovis, commonly known as sheep nose bot, is an obligatory cavitary myiasis of sheep and goats. Oestrus ovis is a widespread parasite, but little is known about the prevalence of oestrosis at the global and broad geographical levels. The present study aimed to explore the epidemiology of oestrosis at the global and regional level to estimate prevalences and their associated factors using a systematic approach. This is, to the author’s knowledge, the first meta-analysis of oestrosis in sheep and goats.

Methods

Published articles were obtained from nine electronic databases (PubMed, CAB Abstracts, Web of Science, Scopus, UCB library, Medline, Biosis Citation Index, Indian journals and Google Scholar) reporting the prevalence of O. ovis in sheep and goats from 1970 to 2018. Pooled prevalences were estimated using a random effect meta-analysis model.

Results

Sixty-six studies were eligible, and data from 40,870 sheep and 18,216 goats were used for quantitative analysis. The random effect estimated prevalence of oestrosis at the global level in sheep was 51.15% (95% CI: 42.80–59.51%) and in goats was 42.19% (95% CI: 33.43–50.95%). The pooled prevalence estimates for Africa, Asia, Europe and the Americas were 47.85% (95% CI: 36.04–59.66%), 44.48% (95% CI: 33.09–55.87%), 56.83% (95% CI: 48.92–64.74%) and 34.46% (95% CI: 19.90–49.01%), respectively. Heterogeneity (I² > 80%) was detected in most pooled estimates.

Conclusions

Oestrosis is highly prevalent in many geographical regions of the world, especially in Europe and Africa. Factors that contribute to the pooled prevalence estimate of oestrosis need to be emphasised in any survey to estimate the true prevalence of oestrosis. Furthermore, there is a need for immunisation or implementation of other preventive measures to reduce the burden of oestrosis in sheep and goats and to improve the health and welfare status.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3597-2) contains supplementary material, which is available to authorized users.

Orbital Inflammatory Syndrome Secondary to Flea Bite

A 34-year-old previously healthy Hispanic male presented to the emergency room complaining of progressive left upper eyelid swelling and pain for more than 2 weeks. He was previously diagnosed and treated for a "pink eye" but failed to improve. He reported a previous "bug bite" around the left lateral canthus a few weeks prior to admission. Computer tomography orbit with contrast showed left exophthalmos, an enhancing left lacrimal gland and orbital inflammatory signs suggestive of possible intraorbital abscess. Intravenous antibiotics did not improve his symptoms. Surgical debridement showed no abscess but inflamed soft tissues and lacrimal gland. Intravenous steroids failed to improve his symptoms. On postoperative day 3, the patient reported that an insect had "jumped" out from his left orbit. Identification of the specimen proved to be a mature flea. Biopsy of the lacrimal gland showed degranulation of eosinophils and foreign body material consistent with probable insect leg parts.

Unilateral conjunctivitis of unique etiology: A case report from Eastern India

A middle-aged female patient from West Bengal presented with complaints of redness, foreign body sensation, and watering for 2 days in the left eye. Slit lamp examination of the left eye revealed several minute white foreign bodies moving over the bulbar conjunctiva. Removal of the foreign bodies under local anesthesia, followed by microscopic examination, suggested the presence of first instar larvae of Oestrus ovis; the sheep nasal bot fly. Diagnosis of unilateral external ophthalmomyiasis was made. Such cases though very infrequently have been reported in the past from Southern and Central Part of India. To the best of our knowledge, this is the second report from Eastern India. A high index of suspicion is necessary both on the part of the clinician and the microbiologist for correct diagnosis.

External ophthalmomyiasis presenting to an emergency department: corneal findings as a sign of Oestrus ovis

Purpose

This study aims to determine the frequency of opthalmyomyiasis externa and the ocular findings of disease in Southern Khorasan.

Methods

All patients referred to the emergency department of Valiaser hospital during the year 2011 with external ophthalmomyiasis were enrolled in this study. The diagnosis of external ophthalmomyiasis was made according to clinical findings and the presence of Oestrus ovis larvae.

Results

There were 18 cases of external ophthalmomyiasis in the emergency department of Valiaser hospital in 2011. Most cases had the common signs and symptoms of allergic conjunctivitis, except for three males who were referred with respective complaints of red eye, foreign body sensation, and swelling around the eyelids after contact injury the previous day; corneal infiltration was present in three cases. The visual acuity among the three cases that had peripheral corneal involvement was 20 / 30 in both eyes. The bulbar conjunctiva showed chemosis in all cases and a ropy pattern discharge that was clinically compatible with external ophthalmomyiasis. However, in one case, microscopic slit lamp examination did not show Oestrus ovis larvae.

Conclusions

The frequency of external ophthalmomyiasis was high in this region. Although external ophthalmomyiasis usually manifests as allergic conjunctivitis, coronary-like corneal infiltration may be considered in the differential diagnosis of external ophthalmomyiasis or toxic insult.

External ophthalmomyiasis: A case report

Ophthalmomyiasis is an infestation of the eye with larvae of most common sheep nasal botfly (Oestrus ovis). We describe a case of ophthalmomyiasis in a 50-year-old man who presented with ocular foreign body sensation, redness and tearing. The causative larvae were removed in the emergency room and sent to laboratory for identification. The patient symptoms improved after topical treatment with antibiotics-steroid combination therapy.

Periorbital edema: a puzzle no more?

PURPOSE OF REVIEW

Periorbital edema is a common problem that deserves scrutiny. Although a variety of healthcare providers may see this clinical entity, ophthalmologists are often consulted along the way toward diagnosis. It can challenge even the most astute clinicians. A diagnosis may reveal merely a bothersome issue or potentially a sight-threatening or life-threatening problem.

RECENT FINDINGS

Comprehensive reviews on this topic are scarce. Textbooks are brief. There are, however, many studies in the scientific literature of notable cases of periorbital edema. The causes generally fall into the categories of infectious, inflammatory or tumors, medication related, and postsurgical or trauma.

SUMMARY

This article synthesizes the current literature on the topic with a case series from our institution. It aims to provide a thorough resource for all practitioners to make the prospect of triaging, diagnosing, and treating periorbital edema less daunting.

External ophthalmomyiasis: a case series

Oestrus ovis or 'sheep botfly' causes common ophthalmomyiasis in warm climates. It is a self-limited infestation with symptoms such as foreign body sensation and/or tearing. The larvae can be observed in the conjunctiva and should be extracted with forceps. The development of larvae beyond the first stage does not occur in healthy humans, although they may penetrate the ocular globe, causing so-called internal myiasis. External ophthalmomyiasis is typical of rural areas, but it may be observed occasionally in urban environments.

Myiasis

Myiasis is defined as the infestation of live vertebrates (humans and/or animals) with dipterous larvae. In mammals (including humans), dipterous larvae can feed on the host's living or dead tissue, liquid body substance, or ingested food and cause a broad range of infestations depending on the body location and the relationship of the larvae with the host. In this review, we deeply discuss myiasis as a worldwide infestation with different agents and with its broad scenario of clinical manifestations as well as diagnosis techniques and treatment.

Oestrus ovis ophthalmomyiasis with keratitis

A 35-year-old male patient presented with complaints of redness, swelling around the eyelids, watering, and irritation in the right eye. At presentation his best-corrected visual acuity was 20/20 partial in the right eye. The tarsal conjunctiva of the upper eyelid showed injection with pseudomembrane. Underneath the pseudomembrane we noticed four motile larvae. The cornea showed an irregular cobweb-like mucous plaque adherent to the epithelium, with a clear stroma. The pseudomembrane was easily peeled-off under topical anaesthesia. The organisms were removed and identified as Oestrus ovis. Three days later the patient was comfortable and his visual acuity was 20/20 in the right eye.

Nasal and ophthalmomyiasis: case report

OBJECTIVE

We report a rare case of a 51-year-old woman with ocular and nasal infestation by Oestrus ovis.

METHOD

Clinical case report and review of current literature regarding nasal and ophthalmomyiasis.

RESULTS

Myiasis is infestation of the tissues and organs of vertebrates by certain dipteran fly larvae. Oestrus ovis myiasis is endemic in the region from North Africa to South Asia, but few cases are reported within the UK. A 51-year-old patient presented and was treated successfully in Sunderland Royal Hospital for combined ocular and nasal infestation with Oestrus ovis.

CONCLUSIONS

Oestrus ovis has a largely subtropical distribution; however, it is important to remember the diversity of disease which can present within the UK from an external source. This point is illustrated by this rare case, which highlights the fact that prompt treatment can avoid poor outcomes for our patients.

Fever and Periorbital Edema: A Review

Fever and periorbital swelling are the manifestation of a broad array of diseases. Among them are emergency situations, which need prompt physician input. Swiftly formulating a differential diagnosis approach is crucial. Diseases causing fever and periorbital edema are either local or systemic. Nevertheless, their impact can be systemic if they evade diagnosis. Infectious diseases and non-infectious diseases (inflammatory and allergic diseases, autoimmune diseases, neoplastic diseases, and trauma) can all lead to fever and periorbital edema. A meticulous history and physical examination in association with targeted tests against the presented spectrum of diseases (specific serological tests, radiological tests, cultures taken from the surface of the periorbital area and other relevant areas, and skin biopsy for histological and microbiological examination) will clarify the diagnosis.

Myiasis as a risk factor for prion diseases in humans

Prion diseases are transmissible spongiform encephalopathies of humans and animals. The oral route is clearly associated with some prion diseases, according to the dissemination of bovine spongiform encephalopathy (BSE or mad cow disease) in cattle and kuru in humans. However, other prion diseases such as scrapie (in sheep) and chronic wasting disease (CWD) (in cervids) cannot be explained in this way and are probably more associated with a pattern of horizontal transmission in both domestic and wild animals. The skin and mucous membranes are a potential target for prion infections because keratinocytes and lymphocytes are susceptible to the abnormal infective isoform of the prion protein. Iatrogenic transmission of Creutzfeldt-Jakob disease (CJD) was also recognized after corneal transplants in humans and scrapie was successfully transmitted to mice after ocular instillation of infected brain tissue, confirming that these new routes could also be important in prion infections. Some ectoparasites have been proven to harbour prion rods in laboratory experiments. Prion rods were identified in both fly larvae and pupae; adult flies are also able to express prion proteins. The most common causes of myiasis in cattle and sheep, closely related animals with previous prion infections, are Hypoderma bovis and Oestrus ovis, respectively. Both species of flies present a life cycle very different from human myiasis, as they have a long contact with neurological structures, such as spinal canal and epidural fat, which are potentially rich in prion rods. Ophthalmomyiases in humans is commonly caused by both species of fly larvae worldwide, providing almost direct contact with the central nervous system (CNS). The high expression of the prion protein on the skin and mucosa and the severity of the inflammatory response to the larvae could readily increase the efficiency of transmission of prions in both animals and humans.

In harm's way: infections in deployed American military forces

Hundreds of thousands of American service members have been deployed to Afghanistan and Iraq since 2001. With emphasis on the common infections and the chronic infections that may present or persist on their return to the United States, we review the data on deployment-associated infections. These infections include gastroenteritis; respiratory infection; war wound infection with antibiotic-resistant, gram-negative bacteria; Q fever; brucellosis; and parasitic infections, such as malaria and leishmaniasis.