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

Oestrus ovis in Ecuador: Importance in the Andean sheep farming

Aim

This study aimed to determine the prevalence of Oestrus ovis in sheep meant for meat commercialization in the main slaughterhouse of the country.

Materials and Methods

Between October 2015 and December 2015, we assessed the occurrence of Oestrus myiasis in the main slaughterhouse localized in Quito. In total, 80 sheep heads were randomly inspected and necropsied. Larvae were removed from nasal cavities and paranasal sinuses and cleaned. ANOVA (generalized linear model) was used to estimate the relationship between sex, age, and place of origin and presence or absence of parasite larvae.

Results

Morphological identification confirmed that 19% (15/80) of the examined animals were positive for Oestrus ovis; from the positive cases, 21% were young animals <12 months old. We found that statistical differences by animal sex, males, were most infested 93% (14/15) than females 7% (1/15). Larvae's L2 were more abundant than other stages (62 of the total 149). 14 of the infested animals were from the Andean places at > 2500 meters above sea level (m.a.s.l.), and only one case from the coastal region at 250 m.a.s.l. with tropical environmental conditions.

Conclusions

Our results showed evidence of the presence of myiasis caused by O. ovis in Andean and coastal places in Ecuador and its adaptation to different environmental conditions from that reported previously in temperate regions from Europe and Africa.

Ophthalmomyiasis externa: A case report from Alkharj, Saudi Arabia

Ophthalmomyiasis is an infestation of mammalian eyes with larvae or maggots of certain flies. Oestrus ovis is the most common cause of human myiasis. This article reports a case of ophthalmomyiasis externa caused by Oestrus ovis (sheep nasal botfly) in a young healthy male, living in Al Kharj, Kingdom of Saudi Arabia. Patient presented with acute symptoms in left eye in April, mimicking as unilateral conjunctivitis/keratitis/external ocular foreign body/uveitis. Prompt diagnosis and mechanical removal of five live larvae from conjunctival fornices of the left eye under topical anaesthesia and cyclopentolate 1% eyedrops, not only relieved patient’s severe symptoms in a single day but also prevented rare yet sight threatening complications.

A case of ophthalmomyiasis interna in the Pacific Northwest

PURPOSE

We report a case of ophthalmomyiasis interna successfully removed in toto with pars plana vitrectomy.

OBSERVATIONS

An 84-year-old woman with recent close contact with lambs presented with a new floater. Examination revealed subretinal tracks pathognomonic for ophthalmomyiasis and a larva suspended in the vitreous. The larva was successfully removed in toto with pars plana vitrectomy by aspiration through the vitreous cutter.

CONCLUSIONS AND IMPORTANCE

Aspiration with pars plana vitrectomy can be considered a primary therapeutic modality for botfly larvae suspended in the vitreous. In our case, in toto removal of the larvae reduced the risk of inflammatory reaction.

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.

Orbital myiasis in eviscerated socket and review of literature

Orbital myiasis is a potentially destructive infestation of the orbital tissues. It is uncommon in clinical practice and is seen in patients with poor hygiene with debilitated or immunocompromised state. We report a case of orbital myiasis in an empty socket of an immunocompetent individual. A 65-year-old immunocompetent patient was found to have orbital myiasis in an empty socket status postevisceration, for which he underwent treatment by manual removal of the larvae after application of a suffocating agent, turpentine oil. A total of 12 larvae were removed over the ensuing week. The tissues healed with secondary intention leaving an irregular healthy scar. It was noteworthy that once eviscerated the eye was neglected by the patient. Empty orbital sockets are potential sites for infestations.

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.

Eosinophilic Pneumonia in a Patient with Bronchial Myiasis: Case report and literature review

Pulmonary myiasis is an unusual form of myiasis in humans and has been recently identified as a cause of eosinophilic pneumonia. We report the case of a 13-year-old Omani boy who presented to the Royal Hospital, Muscat, Oman, in October 2014 with respiratory distress. Bronchial aspirates revealed features of eosinophilic pneumonia. Possible larvae identified in the cytology report, a high immunoglobulin E level and the patient history all indicated bronchial myiasis. The patient was treated with steroids and ventilation and has since been disease-free with no long-term side-effects. To the best of the authors' knowledge, this is the first case of bronchial myiasis in Oman.

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 Caused by a Rare Infesting Larva, Sarcophaga argyrostoma

Purpose. External ophthalmomyiasis (EO) is caused by infesting larvae belonging to various species of flies. Most documented cases result from sheep (Oestrus ovis) and Russian (Rhinoestrus purpureus) botfly larvae, but we recently discovered a rare case of EO caused by flesh fly (Sarcophaga argyrostoma) larvae. Here, we report the case of a patient with EO who had been hospitalized and sedated for 1 week because of unrelated pneumonia. Methods. Case report. Results. A total of 32 larvae were removed from the adnexae of both eyes. Larvae identification was confirmed through DNA analysis. Treatment with topical tobramycin resulted in complete resolution of EO. Conclusion. EO can be caused by S. argyrostoma, and the elderly and debilitated may require extra ocular protection against flies during sedation.

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.

Red eye: rule out Ophthalmomyiasis too

Ophthalmomyiasis is the infestation of human eye by the larvae of certain flies. Sheep botfly commonly manifests as Ophthalmomyiasis externa when there is conjunctival involvement or rarely as Opthalmomyiasis interna when there is larval penetration into the eyeball. It appears to be more common than what has been indicated by previously published reports. We present a report of seven cases of Ophthalmomyiasis by Oestrus ovis, from central India who presented with features of conjunctivitis varying between mild to severe. The larvae were seen in bulbar and palpebral conjunctiva and also entangled in lashes with discharge. Since the larvae are photophobic, it is prudent to look for them in the fornices and also in discharge. Prompt removal of the larvae from the conjunctiva helps in relieving the symptoms and also prevents serious complications. Taxonomic identification of the species is important to estimate the risk of globe penetration by the larvae.

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.

Vidi, vini, vinci: External ophthalmomyiasis infection that occurred, and was diagnosed and treated in a single day: A rare case report

Ophthalmomyiasis is an infestation of eye with larvae or maggots of certain flies. Oestrus ovis (sheep nasal botfly) belonging to family Oestridae is the most common cause of human myiasis. We describe here an acute presentation of a case of external ophthalmomyiasis, i.e., infestation of conjunctiva due to first instar larvae of Oestrus ovis. In this case report the occurrence, diagnosis and treatment all took place in the setting of a single day. Prompt treatment by removal of larvae mechanically followed by instillation of antibiotic and steroid eye drops helped to prevent serious complications. The taxonomic identification of fly is also important as some fly species are capable of penetrating deeper tissues of eyes, which is sight threatening.

[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.

Prevalence and intensity of Oestrus ovis in sheep of Shiraz, southern Iran

Two thousand and two heads obtained from slaughtered sheep at the Fars abattoirs (Shiraz, Southern Iran) between April 2006 and April 2007 were examined for the presence of Oestrus ovis larvae. Of the total heads, 995 (49.7%) were infested with O. ovis larvae. O. ovis larvae were observed in both sexes and all age groups in each season of the year. A total of 6264 larvae were collected. The overall larval intensity for the infested sheep was 6.3, with 3.9 in spring, 5.3 in summer, 5.9 in autumn and 7.8 in winter. Prevalence ranged from 23.3% in spring to 80% in winter. Increased infestation was observed in older animals.

[Ophthalmomyiasis interna: two case studies]

Myiasis is a pathology caused by the presence of fly larvae in the human organism. Ophthalmomyiasis interna is characterized by the presence of the parasite within the eye but also in the eyelids and the orbit. Herein, the authors present the clinical cases of two patients presenting ophthalmomyiasis interna revealed by retinal detachment for the first patient and by panuveitis for the second patient. These two cases should make ophthalmologists aware of this rare disease that can effect patients living in direct contact with ovine races.

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.

Prevalence and intensity of Oestrus ovis in Akkaraman sheep in the Konya region of Turkey

Slaughterhouse surveys to determine the prevalence and intensity of larval Oestrus ovis Linnaeus (Diptera: Oestridae) in sheep, were conducted monthly for 1 year in Konya, Turkey. A total of 624 sheep, selected at random, were examined and 59% were found to be infested by O. ovis. A total of 8801 larvae were collected, of which 68.9% were first-stage, 19.1% second-stage and 12% third-stage larvae. All three larval stadia were seen in each month of the year. The larval intensity for infected sheep was 23.9, with 16.48 L(1), 4.55 L(2) and 2.87 L(3). The monthly prevalence ranged from 34.6% in January to 76.9% in October. The largest number of larvae (180) was obtained from a sheep in August (122 L(1), 52 L(2) and 6 L(3)). The infestation rate was higher in 4 - 6-year-old sheep, at 72.6%. The infestation rates were 64.4% in female and 47.5% in male sheep.

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.

Ophthalmomyiasis in Oman: a case report and comments

A case of external ophthalmomyiasis caused by the first instar larvae of the sheep nasal botfly (Oestrus ovis) has been reported for the first time from the Sultanate of Oman, Southern Arabia. Sixty larvae were removed from the left eye of a 21-year-old male student, who acquired the infection during a field trip. The manual removal of larvae using a swab stick was the only effective treatment. The larval characteristics are described with illustrations, and the status of O ovis ophthalmomyiasis in the Middle East is discussed. The folk treatment administered for fly-mediated ophthalmomyiasis in Oman is also reported. Ophthalmomyiasis may not be a serious public health problem in Oman, but a nationwide survey of all myiases may be worthwhile.

Sheep oestrosis (Oestrus ovis Linné 1761, Diptera: Oestridae) in Sardinia, Italy

Oestrosis, the nasal myiasis of sheep and goats, is caused by the larvae of Oestrus ovis L. 1758 (Diptera, Oestridae) that develop from the first to the third stage larva in the nasal cavities and frontal sinuses of affected animals. The authors report the results of an epidemiological study of oestrosis of sheep in Sardinia, Italy. Heads of 6-month to 10-year-old Sardinian sheep (n=566) from 124 free-ranging flocks were examined for the presence and location O. ovis larvae from December 1996 to November 1997. Larvae were collected, counted, and larval stages were identified. O. ovis larvae were found in 100% of examined flocks and in 91% (514/566) of examined sheep. The monthly prevalence ranged from 69% in May to 100% in July. First stage larvae were found in 82% (463) of all heads examined, second stage larvae in 65% (367) and third stage larvae in 10% (56). The majority of sheep harboured first stage larvae, with prevalences of over 80% throughout most of the study period. The prevalence of O. ovis found in this study of Sardinian sheep is the highest reported in the Mediterranean area. The high percentage of first stage larvae found throughout the entire study period may be due to a brief period of decreased rate of larval maturation, in particular in December 1996 (96%) and January-October 1997 (94%). Third stage larvae were consistently present, often however, with extremely low prevalences compared to total larval burden.

Cuterebra Ophthalmomyiasis

PURPOSE/METHODS

We used a simple laboratory method to identify the first instar stage of a Cuterebra larva that emerged from the conjunctiva of a 14-year-old boy with ipsilateral decreased vision, subretinal hemorrhages, and linear streaks in the fundus. The maggot was removed from the conjunctiva and cleared in glycerol solutions.

RESULTS/CONCLUSIONS

Light microscopy disclosed spines characteristic of Cuterebra larvae. Scanning electron microscopy is not necessary for diagnosis of Cuterebra ophthalmomyiasis even if samples are limited to the larval thorax.

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.