External ophthalmomyiasis manifesting with keratouveitis

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.

Human myiasis cases originating and reported in africa for the last two decades (1998-2018): A review

The article reviews literature on myiasis in Africa and cases that originated in Africa over the last two decades (1998-2018). The relevant literature was obtained by using several databases (Science-Direct, JSTOR, Google Scholar, Ebscohost and PubMed). We searched for the following words or their combination myiasis, maggots, fly species responsible for myiasis found in Africa, and the different types of myiasis. References in several articles provided links to other relevant works. Only papers written in English were reviewed. In total, we reviewed 51 articles which covered a total of 849 myiasis cases. The review encompasses geographical distribution of the disease, dipteran species responsible, predisposing factors, sex of the patient, type of myiasis and treatment. Myiasis is found in most parts of the African continent, however only 18 articles reported myiasis cases in Africa during the period under review. The rest of the articles report cases from the rest of the world but acquired by travellers when visiting Africa. Cordylobia anthropophaga (Blanchard) was responsible for 93.28% of all the reported cases in this review. The low number of articles on human myiasis reported in Africa may be due to underreporting by physicians or most cases are not diagnosed. Therefore, the actual prevalence of myiasis in Africa is currently unknown.

Human ophthalmomyiasis caused by Oestrus ovis-first report from Croatia and review on cases from Mediterranean countries

Oestrus ovis is the most common cause of human ophthalmomyiasis. So far, majority of ophthalmomyiasis cases have been reported from Mediterranean countries, but not from Croatia. In current study, we present first two cases of human ophthalmomyiasis in Croatia, caused by O. ovis larvae. Reviewing a PubMed database, additional 259 cases of human ophthalmomyiasis in countries of Mediterranean basin have been reported. A total of 260 (99.62%) cases had external, while 1 (0.38%) had internal form of ocular myiasis. In all cases, O. ovis larvae were identified as the causative agent. O. ovis infestation is usually reported in shepherds and farmers although there is a high prevalence of infection in urban areas as well. Various climatic factors influence O. ovis larvipositional activity. Air temperature is the most important factor affecting O. ovis larviposition, while humidity, wind speed, and time of the day play only a moderate role. Most common symptoms of ophthalmomyiasis are irritation and redness, and in more than half of cases infestation is multiple. Ophthalmomyiasis interna is eye-compromising condition. Since there is reduced awareness among patients and medical professionals, the real number of ophthalmomyiasis cases is probably significantly higher than published. Global warming predisposes future increase of O. ovis prevalence in humans, which emphasizes the need for mandatory reporting and surveillance of disease.

External ophthalmomyiasis due to Dermatobia hominis. A case report

CLINICAL CASE

A 46-year-old woman with no relevant medical history, native of Honduras and resident in Spain for one and a half months. The patient went to the Emergency Department due to inflammation of the upper eyelid of the right eye, with an area that simulated an abscess. This was drained (obtaining hardly any purulent content). Treatment was prescribed with oral and topical antibiotics, as well as an anti-inflammatory drug. One week later the patient returned, with improvement of the inflammatory signs, but with discomfort and corneal erosions. After eversion of the upper eyelid, a «worm» type parasite emerged from the tarsus. The extraction was completed with a clamp, and was later identified as Dermatobia hominis (Dh) by examination of a fresh specimen. The subsequent outcome of the patient was favourable.

DISCUSSION

Preseptal cellulitis in patients from tropical and sub-tropical areas can be caused by Dh.

External Ophthalmomyiasis Due to Dermatobia hominis Masquerading As Orbital Cellulitis

Human parasitization by oestrid flies is a rare occurrence. The authors report a case of ophthalmomyiasis externa caused by Dermatobia hominis infestation in a 10-year-old female. Misdiagnosis resulted in a delay in treatment, which can be potentially devastating in cases of orbital or ocular involvement. The treatment of choice is early surgical removal of the larvae to minimize the inflammatory response and the extent of surgery. Patients should also be screened for multiple sites of cutaneous infestation. When the organism is completely excised, the prognosis is good.

Ocular parasitoses: A comprehensive review

Parasitic infections of the eyes are a major cause of ocular diseases across the globe. The causative agents range from simple organisms such as unicellular protozoans to complex metazoan helminths. The disease spectrum varies depending on the geographic location, prevailing hygiene, living and eating habits of the inhabitants, and the type of animals that surround them. They cause enormous ocular morbidity and mortality not because they are untreatable, but largely due to late or misdiagnosis, often from unfamiliarity with the diseases produced. We provide an up-to-date comprehensive overview of the ophthalmic parasitoses. Each section describes the causative agent, mode of transmission, geographic distribution, ocular pathologies, and their management for common parasites with brief mention of the ones that are rare.

External ophthalmomyiasis: a case series and review of ophthalmomyiasis in Turkey

Ophthalmomyiasis externa is the infestation of the superficial external ocular structures by fly larvae. This is a particularly rare condition, which has nevertheless been reported in several countries worldwide. It is common in sheep-farming areas, especially in Mediterranean countries. The patients may present with classic conjunctivitis, pseudomembranous conjunctivitis, conjunctival hemorrhages, punctuate keratitis, keratouveitis, and eyelid edema with erythema. Herein, we present three cases of external ophthalmomyiasis caused by Oestrus ovis larvae and review ophthalmomyiasis cases reported from Turkey.

Ophthalmomyiasis Externa: A Report of Three Cases

Three patients were admitted to our clinic with symptoms of conjunctivitis. On ocular examination, moving larvae were seen in the conjunctival sac. All of the larvae were immobilized by topical cyclopentolate and removed mechanically under topical anesthesia. The patients healed without any complications after the treatment. Physicians should consider ophthalmomyiasis externa in patients presenting with similar symptoms, especially in areas with high numbers of livestock. Otherwise the diagnosis can be missed.

Diagnosis of ophthalmomyiasis externa by dermatoscopy

Ophthalmomyiasis in humans caused by the larvae of the sheep nasal botfly (Oestrus ovis) and is a rare phenomenon in Israel. We describe the utilization of the dermatoscope as a diagnostic tool for the facilitation of early diagnosis of conjunctivitis due to the infestation of the eyes by the sheep nasal botfly in two patients. After the physical removal of the larvae with the help of a cotton swab applicator under a slit lamp examination and the topical use of antibiotics, the clinical symptoms improved within 1-2 days. Undoubtedly the dermatoscope played a crucial role leading to the definitive diagnosis and immediate therapeutic intervention.

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.

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.

Symblepharon secondary to ophthalmomyiasis externa in a dog

A 4-month-old crossbred female dog presented with complaints of poor vision and odd appearance of the eyes. At the age of a month, the animal was found lying in a railway road in a very bad condition and was rescued from death. At that time, the patient was presented with severe bilateral ocular discharge, and from both eyes, dipterous fly larvae were extracted. The dog was given symptomatic treatment (deworming, topical and systemic antibiotics, nutritional support) but never regained a normal eye appearance. At the time of the initial presentation, it had severe vision impairment because of bilateral cicatricial symblepharon, total in the left eye and occupying 3/4 of the cornea in the right eye. Surgery was proposed to attempt a resolution. Superficial keratectomy was performed in both eyes. After a midline incision in the cornea, the conjunctiva was dissected away. The conjunctiva was apposed to and sutured to the limbus and secured in the upper and lower conjunctival fornix. Additionally, in the left eye, a lateral canthotomy and canthoplasty were performed to enlarge the size of the eyelid opening. The corneal epithelium healed without complications, the patient regained vision, and after 36 months of follow-up, no recurrences were observed. To the authors' knowledge, this is the first report of symblepharon secondary to ophthalmomyiasis externa in a dog.

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.

[Conjonctival human myiasis by Oestrus ovis in southern Tunisia]

Conjunctival myiasis is the most frequent expression of ocular myiasis. It results from infestation of the conjunctiva by the larval form of flies. We report 11 cases of conjunctival myiasis to encourage ophthalmologists to be aware of the diagnosis of external ophthalmomyiasis, its complications, and its treatment. Most of the cases occurred amongst males during summer and autumn. Symptoms are related to the foreign body with a sudden evolution. We diagnosed this affection by direct observation of the larva on conjunctiva. The number of larvae ranged from 2 to 30. The larvae were identified as first-instars of Oestrus ovis. The treatment was performed by removal of the larvae which resulted in rapid improvement. In conclusion, early diagnosis and management are important in preventing complications of internal ophthalmomyiasis.