First Report of Human Nasal Myiasis Caused by Eristalis tenax in Iran (Diptera: Syrphidae).

We report a case of human nasal myiasis caused by flower fly larva in a 14-year-old rural girl in Central Province of Iran. Entomological studies on larva showed the larva as Eristalis tenax which is a rarely cause of nasal myiasis. This is the first reported case of E. tenax larva causing human nasal myiasis in Iran.

Introduction

Myiasis is a pathogenic condition found in live humans and animals caused by various species of dipteran larvae (Zumpt 1965). Myiasis is usually classified from an entomological or a clinical point of view. Entomologically, flies may be classified in to three myiasis-producing groups: obligatory, facultative, and accidental. Clinically, myiasis can be classified according to the part of the body affected (Langan et al. 2004).

In Iran, many cases of human myiasis have been reported. The first case was reported by Minar when he recovered Oestrus ovis larva from the eye of an Iranian woman in Tehran (Minar 1976). Myiasis is repeated several times as ophthal myiasis (Janbakhsh et al.1977), urogenital myiasis (Jdalayer et al. 1978), orbit myiasis (Khataminia and Elyasi 1996), pharyngeal myiasis (Karimi and Vahidi 1999), ear myiasis (Talari et al. 2002), oral mucosa myiasis (Hakimi and Yazdi 2002), wound myiasis (Talari et al. 2004) and auricular myiasis (Tirgarie et al. 1977, Yaghoobi et al. 2005).

Recently, ophthalmomyiasis in a 62-yr old male Afghan from Isfahan Iran by Sarcophaga (Razmjou et al. 2007), gingival myiasis by Wohlfahrtia magnifica in a 4 yr old boy from Bushehr, Iran (Mohammadzadeh et al. 2008) and human extensive head skin myiasis by Chrysomya bezziana in 5 yr old boy in Iran (Soleimani et al. 2009). The present case is of nasal myiasis caused by larva of E. tenax for the first time in Iran.

Case report

The patient was a 14 yr old rural girl. She was suffering from myiasis since 5 months ago, who developed coryza, nasal grip, mild dyspenea and coughing. She had taken antibiotic, antihistamine, and topical corticosteroid, but none of them had sufficient effects. Radiographs have showed only minimal septal deviation and minimal opacity in left frontal and maxillary sinuses. Finally during several sneezing pulpy mass of the left nasal, released and she referred to infectious specialist, the larva was preserved in 70% Methanol by physician and sent to the parasitological laboratory, Faculty of Medicine, University of Arak, for identification. Our precise identification indicated that the larva is the rat-tailed maggot (Eristalis tenax) according to the following morphological characters of larva: referring to the long telescopic, three- segmented respiratory tube at their posterior end. (Mullen et al. 2002). Fig. 1 is a picture of the larva of the relevant specimen.

Fig. 1.

Larva of Eristalis tenax isolated from the nose of the patient (original photo)

Discussion

Nasal myiasis is an infection of nasal cavities by larvae of Diptera. It is a common disease in tropical and developing countries (Aydin et al. 2006). Parasites are quite mobile and their clinical signs vary. Symptoms always appear abruptly. The main symptoms are a foreign body sensation and itching in the throat, being followed by cough and then other various respiratory and nasal manifestations such as nasal discharge, sneezing, laryngospasm, dyspnea and stridor (Wolfelschneider and Wiedemann 1996, Massodi and Hosseini 2004).

Many cases of nasal myiasis have been reported world wide, caused by several different species including Oestrus ovis in Algeria (Favier 1958), and France (Delhaes et al. 2001), Phaenicia sericata in 2 comatose patients in Arizona (Beckendorf et al. 2002), Chrysomya bezziana in a 80 yr old woman in Malaysia (Lee et al. 2005), Cochliomyia hominivorax in French Guiana (Coppie et al. 2005), Drosophila melanogaster in a 33 yr old in Turkey (Aydin et al. 2006), Sarcophaga in a 16 yr old girl in Turkey (Meral TÜRK et al. 2006), in a 70 yr old female patient presenting malignant nasal neoplasia and myiasis (Manfrim et al. 2007) and in a 70 yr old female in Korea, caused by Lucilia sericata (Tae-soo Kim et al. 2009).

The terms flower flies refer to their common habit of visiting flower for nectar and pollen and larvae of E. tenax called rat- tailed maggot referring to the long, telescopic, three-segmented respiratory tube at their posterior and by which they breathe at the water surface (Mullen et al. 2002). The larva of E. tenax develops in sewage, liquid, excrements and organic materials in decomposition, including carcasses, and occasionally, they can be found in relatively clean water (James 1947).

The first case of myiasis by E. tenax was reported by Hall (Hall 1918).Since then, many more cases of human myiasis have been reported by E. tenax, which include intestinal myiasis (Lakshminaraynana et al. 1975), rectal myiasis (Hira 1977), gastrointestinal myiasis (Kun et al. 1998), intestinal myiasis (Aguilera et al. 1999, Whish- Wilson 2000, Dubois et al. 2004), human pseudomyiasis in Brazil (Garcia- Zapata et al. 2005), urinary myiasis in a 58 yr old woman in Turkey (Mumcuoglu et al. 2005) human myiasis by E. tenax in Brazil (Fernandes et al. 2009), and accidental genital myiasis by E. tenax in a 27 yr old woman in Chile (Gonzalez 2009).

This current study, illustrates several interesting points. It shows that, our case lived in rural area, in a poor hygienic condition and lack of awareness was considered the predisposing factors for larval infestation in this patient. It is also noteworthy that nasal myiasis caused by larva of E. tenax is uncommon in human. Myiasis of this type has not been reported previously from Iran and this case is the first report of human nasal myiasis caused by E. tenax in Iran.