A rare and medically significant case from Greece has documented a woman expelling bot fly larvae from her nose after weeks of unexplained symptoms. The case highlights an unusual presentation of nasal infestation caused by Oestrus ovis, with an exceptionally rare finding, development of larvae to advanced stages and even pupation within a human host.
The case, reported in October 2025, involved a 58-year-old woman who worked outdoors on a Greek island, grazing sheep. During hot, dry weather, she noticed flies swarming around her face.
About a week later, she developed:
Progressive facial (maxillary) pain
Persistent coughing over 2–3 weeks
One day her symptoms escalated until she experienced a startling event, sneezing out worm-like organisms from her nose, which prompted her to seek immediate medical consultation.
An ENT doctor removed:
10 larvae at different developmental stages
1 pupa (puparium)
from her maxillary sinus. The patient recovered completely after treatment with nasal decongestants.
Oestrus ovis or sheep bot fly is a parasite commonly found in sheep and goats, especially in warm, dry regions such as the Mediterranean. Human infection is accidental and relatively rare.
Historically, it was believed that Oestrus ovis larvae could not develop beyond the first stage (L1) in humans. However, in this case larvae and pupae was found.
Pupation within a human host is considered biologically unlikely, as the human body typically does not provide the environmental conditions required for this stage.
Diagnosis was confirmed using both:
Morphological examination (appearance and structure of larvae)
Molecular testing (PCR and DNA sequencing)
Genetic analysis showed 100% identity with known Oestrus ovis sequences, confirming the parasite’s identity.
Researchers suggested that anatomical factors may have played a role. The patient had a severely deviated nasal septum, which may have:
Prevented normal expulsion of larvae
Allowed prolonged development within the sinuses
Created conditions that enabled rare pupation
Another hypothesis is that this could represent an early sign of parasite adaptation, though more data is needed.
Clinicians working in rural or livestock-associated environments should remain aware of these possibilities.
Symptoms can vary depending on severity but may include:
Nasal irritation or discomfort
Facial pain or sinus pressure
Sneezing or nasal discharge
Sensation of movement inside the nose
Coughing (if larvae migrate or irritate airways)
In this case, symptoms progressed gradually before the visible expulsion of larvae.
The reported case of nasal myiasis caused by Oestrus ovis in Greece presents a rare instance of larval development and pupation within a human host. While the patient made a full recovery, the case contributes to emerging evidence that challenges previous assumptions about the parasite’s life cycle in humans. Further research is required to understand the mechanisms behind such atypical presentations.
Reference
Kioulos, Ilias P., Emmanouil Kokkas, and Evangelia Theophano Piperaki. “Oestrus ovis Nasal Myiasis with Pupation in Human Host, Greece, October 2025.” Emerging Infectious Diseases 32, no. 3 (March 2026). https://doi.org/10.3201/eid3203.251077
