Woman Sneezes Maggots: Rare Case of Human Nasal Myiasis

In a startling medical case, a 58-year-old woman in Greece experienced a unique and unsettling symptom: sneezing out maggots. Doctors documented the incident, confirming the presence of larvae from the sheep bot fly, Oestrus ovis, within her nasal and sinus cavities. This rare occurrence, known as nasal myiasis, highlights the potential for human infestation by this typically animal-borne parasite.

What is Nasal Myiasis?

Nasal myiasis is a parasitic condition caused by the larvae of certain flies. Oestrus ovis, commonly known as the sheep bot fly, is a cosmopolitan parasite primarily affecting small ruminants like sheep and goats [1]. Human infestations are accidental, occurring when flies deposit their larvae into the nostrils.

The Case in Greece

The patient reported experiencing worsening pain around her upper jaw and severe coughing fits after working outdoors near sheep. She ultimately sought medical attention after sneezing out what she described as “worms.” Examination revealed 10 larvae in various stages of development, along with one puparium – the hardened, protective casing in which the larva develops into an adult fly – extracted from her maxillary sinus [1].

Genetic testing and DNA sequencing confirmed the larvae were Oestrus ovis [1]. Remarkably, the puparium was found within the patient’s sinus, a previously undocumented occurrence. Experts noted that pupation within a human host was considered “biologically implausible” due to unfavorable temperature, humidity, and immune responses [1].

Why Did Pupation Occur?

Researchers speculate that a combination of factors contributed to the unusual pupation. A large initial dose of larvae, coupled with the patient’s deviated septum, may have impeded the larvae’s normal expulsion, allowing them to progress to the pupal stage [1]. The deviated septum created a bottleneck, preventing the larvae from being easily expelled.

Life Cycle of the Sheep Bot Fly

The adult sheep bot fly is a bee-sized insect, approximately 10-12 millimeters long, with a banded grey body and yellow head and legs [1]. The fly lays eggs that hatch into larvae within the female’s body. The female then deposits these larvae, typically in a mucous droplet, directly into the nostrils of a host animal – usually sheep, deer, or goats [1].

Once inside the nasal passage, the larvae develop and migrate to the sinuses. After reaching maturity, they are typically expelled by sneezing, burrow into the ground, and pupate before emerging as adult flies [1].

Implications and Prevention

While rare, this case underscores the importance of awareness among clinicians regarding the possibility of human Oestrus ovis infections, particularly in regions where sheep and goats are prevalent [1]. The patient in Greece made a full recovery after treatment with nasal decongestants [3]. Preventive measures include avoiding close proximity to areas with high fly populations and using insect repellent when working outdoors.

Key Takeaways

• Nasal myiasis caused by Oestrus ovis is a rare condition in humans.
• The sheep bot fly typically affects livestock, but accidental human infestations can occur.
• Pupation of the larvae within a human host is extremely unusual.
• A deviated septum and a large initial larval load may contribute to successful pupation.
• Clinicians should be aware of this potential infection in endemic areas.