Ophthalmomyiasis caused by the sheep nasal bot, Oestrus ovis (Oestridae) larvae, in the Benghazi area of Eastern Libya

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.

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.

Animal-inflicted ocular and adnexal injuries in children: A systematic review

Eye injury remains the leading cause of monocular blindness in children despite 90% of injuries being potentially preventable. Children interact with animals in a variety of situations, and the associated dangers may be underestimated. Animals are capable of causing ocular and adnexal injuries that are cosmetically and visually devastating. We examine the current literature regarding the nature and severity of animal-inflicted ocular and adnexal injuries in children.

Nasal Oestrosis in a Jamunapari goat

Oestrus ovis is a well-known parasite of the nasal cavities and adjoining sinuses in sheep and goats. A 3-year-old female Jamunapari goat was presented with a history of anorexia, weight loss, in-coordinated movements, nasal discharge since 10 days and two nasal bots expelled during sneezing 3 days back. Upon clinical examination the animal was dull, dysphonic, unsteady gait and having blocked nostrils with thick mucoid discharge along with an increased respiratory rate. Parasitiological examination revealed it as an O. ovis (nasal bots). The occurrence of nasal bots in a goat and its successful therapeutic management and public health significance have been reported and discussed in the present communication.

Oestrus ovis as a Cause of Red Eye in Aljabal Algharbi, Libya

Purpose:

To study the common presenting signs of external ophthalmomyiasis caused by Oestrus ovis larvae in Aljabal Algharbi province, Libya.

Materials and Methods:

A prospective non- comparative study was conducted from September 2009 to July 2010 at the Gharian outpatient clinic, Gharian, Aljabal Algharbi, Libya. The common presenting features of patients with external ophthalmomyiasis and data on the organism that caused the disease were collected.

Results:

Twenty one cases diagnosed with external ophthalmomyiasis were recorded. There were fourteen males (66.67%) and seven females (33.33%) in the cohort. The mean age was 14.29 ± 3.46 years (range, 8 years to 22 years: males; 13.39 ± 3.03 years and females; 16.67 ± 3.75 years). The main complaint was redness (100.00%), itching (71.43%) and tearing (57.14%). Twelve patients (57.14%) were from rural areas and 9 patients (42.9%) were from urban areas. The causative organism was found to be first instar of Oestrus ovis larvae.

Conclusion:

External ophthalmomyiasis caused by Oestrus ovis can cause red eye in patients from Aljabal Algharbi, Libya and requires careful examination to ensure early diagnosis and proper treatment.

Bilateral ocular myiasis interna caused by botfly (Oestrus ovis): a case report

The sheep nasal botfly Oestrus ovis is the commonest of several species of dipteran fly whose larvae are obligatory parasites in the nasal cavities and frontal sinuses of sheep but may cause infestation (myiasis) in man, commonly as external infestations and rarely, involves inner coat of the eye (Ocular myiasis interna). We report an imported case of Bilateral Ocular myiasis interna in an Indian boy.

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.

Ophthalmomyiasis caused by a Phormia sp. (Diptera: Calliphoridae) larva in an enucleated patient

Ophthalmomyiasis rarely occurs worldwide, and has not been reported in Korea. We present here a case of ophthalmomyiasis caused by Phormia sp. fly larva in an enucleated eye of a patient. In June 2010, a 50-year-old man was admitted to Dankook University Hospital for surgical excision of a malignant melanoma located in the right auricular area. He had a clinical history of enucleation of his right eye due to squamous cell carcinoma 5 years ago. During hospitalization, foreign body sensation developed in his right eye, and close examination revealed a fly larva inside the eye, which was evacuated. The larva was proved to be Phormia sp. based on the morphology of the posterior spiracle. Subsequently, no larva was found, and the postoperative course was uneventful without any complaints of further myiasis. This is the first case of ophthalmomyiasis among the literature in Korea, and also the first myiasis case caused by Phormia sp. in Korea.

[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.

External ophthalmomyiasis by oestrus ovis: an unknown endemic eye disease in rural parts of central India

SUMMARY

Although much general information has accumulated about ocular myiasis, there are very few reports about the same amongst the Indian population. We present a case series, comprising of 13 documented cases of external ophthalmomyiasis due to Oestrus ovis, detected at regular intervals in a small geographical area of rural central India, which strongly indicated the presence of a previously unknown endemic eye disease of this region.

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

Myiasis is the feeding of fly larvae on vertebrates. The sheep bot fly larva of Oestrus ovis is a mammalian parasite of the skin, nose, ears, and eyes. When the larvae infest and feed on the structures of the eye, the condition is termed ophthalmomyiasis. Most often this infestation is limited to the external structures of the eye and is referred to as ophthalmomyiasis externa. The features of this condition are severe local inflammation, positive foreign body sensation, erythema, and lacrimation. Vision may or may not be reduced, depending on involvement of the cornea. A 20-year-old white male soldier sought treatment for an inflamed eye and an irritated cornea OS. His eyelids were swollen with marked periorbital edema and conjunctival erythema OS. On slitlamp examination, small whitish organisms were viewed on the conjunctiva OS. The organisms were removed, preserved, and sent to Nova Southeastern University where they were identified as O. ovis first-stage larvae. The patient was treated with antibiotic ointment, and the inflammation resolved within 1 week. O. ovis has a worldwide distribution, and although sheep are the preferred host, humans may also serve as an intermediate host in the organism's life cycle. This case represents one of several reports of ophthalmomyiasis in the Middle East caused by O. ovis. U.S. troops stationed in Iraq and surrounding areas are vulnerable to eye infestation by fly larvae, and health care providers need to include this condition in their differential diagnosis of anterior segment inflammatory disorders.

Oestrus ovis larval myiasis among goats in northern Jordan

From December 1998 to December 1999, heads of 520 local goats slaughtered at the Irbid, Ramtha and Howarra Abattoirs (northern Jordan) were examined for the three larval instars (L(1)-L(3)) of Oestrus ovis. Of 520 heads, 126 (24%) were infested with O. ovis larvae. All three larval instars were observed in both sexes; all age groups were infested in each month of the year. The mean age of the goats sampled was 1.5 years. The numbers of parasites infesting hosts showed a significant (P<0.05) correlation with sheep age (r(sp)=0.31-0.42) for all three larval instars. The numbers of larvae in each host followed an overdispersed distribution, which fit a negative-binomial model (but not a Poisson distribution). There were more parasites recorded in the presence of purulent discharge or laryngitis, fewer in the presence of catarrhal discharge and no association with pharyngitis sinusitis, or rhinitis.

Orbital myiasis: a case report

Myiasis; a term first introduced by HOPE refers to invasion of living tissue of humans and other mammals by the eggs or larvae of flies of the order of Diptera. Orbital involvement occurs in approximately 5% of all cases of myiasis. A 72 year old patient is presented with orbital myiasis that was successfully treated by enucleation and grafted with split thickness of skin.

Age and seasonal variations in the prevalence of Oestrus ovis larvae among sheep in northern Jordan

During the period March 1996-July 1997, 417 heads of Awassi sheep slaughtered at the Irbid Abattoir (northern Jordan) were examined for the three larval instars (L1, L2 and L3) of Oestrus ovis. Of the 417 heads, 242 (58%) were infested with O. ovis larvae. Larval numbers were highly aggregated. The lowest number of larvae and the lower quartile were both zero, whilst the median was two and the upper quartile was 12. The highest number of larvae recovered from one head was 151. All three larval instars were observed in each month of the year. July and October had the highest proportions of L1, 75 and 78%, respectively, among infected animals (adjusted for age). The number of larvae increased with age. Infestation with live larvae was associated with inflammatory responses in the upper respiratory tract and with catarrhal or purulent discharge. The percentage of infested sheep and the mean monthly total number of larvae/sheep peaked in the warmer part of the year. Most larvae were L1 except during the spring when L2 and L3 predominated. Distribution analysis demonstrates that the numbers of larvae recovered in the sheep population followed a negative-binomial distribution. Furthermore, the negative-binomial constant k for each month correlated with the monthly prevalence.

Ophthalmomyiasis externa caused by Oestrus ovis L. in the Ajloun area of northern Jordan

During the years 1990-1991 17 cases of ophthalmomyiasis externa due to the sheep nasal botfly, Oestrus ovis, were reported from the Ajloun area in northern Jordan. Symptoms included mild to severe conjunctivitis, cellulitis, lacrimation and conjunctival hyperaemia. All cases were among males, and they occurred either from April to July or from September to November.

Oestrus ovis myiasis in Libyan sheep and goats

The heads of 1,489 sheep and 320 goats were examined for larvae of Oestrus ovis at 17 abattoirs in northern Libya in July to November 1988. The prevalence of O. ovis in sheep was 22.6% and in goats it was 18.4 per cent. Up to 14 and 11 larvae were collected from individual sheep and goats respectively. All larvae were recovered from the nasal passages and frontal sinuses, but only second and third instars were seen.

Conjunctival ophthalmomyiasis caused by the sheep nasal botfly (Oestrus ovis)

Three patients had conjunctival ophthalmomyiasis caused by the ovine nasal botfly. All patients had a sudden onset of redness, tearing, and foreign-body sensation of the affected eye. One to nine Oestrus ovis first-instar larvae were removed from the bulbar or palpebral conjunctiva of each patient. Symptoms and clinical signs resolved after mechanical removal of the larvae. Specific taxonomic diagnosis of O. ovis larvae was determined on the basis of characteristic conformation of the terminal end of the larval caudal segment as seen by use of light microscopy.

Human external ophthalmomyiasis caused by the horse bot fly larva (Gasterophilus spp.)

We report the case of a 20-year-old woman who presented with a subconjunctival maggot. The maggot was removed and identified as the larval form of the horse bot fly (Gasterophilus spp.). The patient had been grooming infected horses in a stable prior to presentation. To our knowledge, this is the first well documented case in the ophthalmic literature of external ophthalmomyiasis caused by Gasterophilus spp.

External ophthalmomyiasis caused by the sheep bot Oestrus ovis L

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