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The human aural myiasis caused by Lucilia sericata
Aural myiasis
Dariusz Kaczmarczyk, MD1; Jerzy Kopczyński, MD2; Joanna Kwiecień, MD2, Marek Michalski, PhD3; Piotr Kurnatowski, MD, PhD4
1Department of Head and Neck Neoplasms Surgery, Medical University, Lodz (Poland)
2ENT Department, Provincial Specialistic Hospital, Zgierz (Poland)
3Natural History Museum, University of Lodz, Lodz (Poland)
4Chair of Biology and Medical Parasitology, Medical University, Lodz (Poland)
A corresponding author: Piotr Kurnatowski; Hallera sq.1, 90-647 Lodz (Poland); phone: 48 42 63 93370; fax: 48 42 63 93371; e-mail:
Requests for reprints should be sent to: Piotr Kurnatowski; Hallera sq.1, 90-647 Lodz (Poland)
Key words: myiasis, auricula
ABSTRACT
Myiasis is a rare, worldwide, human disease with seasonal variation, caused by developing larvae of a variety of fly species. It can be dangerous, when infestations penetrate into the brain. In available literature we have found only a few papers concerning ear myiasis caused by Lucilia sericata. We report 2 cases of aural myia-sis. Early intervention (surgical removal, occlusion) in such cases will allow to avoid complications. Larvae, for further examination, should be killed by immersion in very hot water, then they should be preserved in an ethanol.
INTRODUCTION
Myiasis is a rare, worldwide, human disease with seasonal variation, caused by developing larvae of a variety of fly species, among them the most common are Dermatobia hominis and Cordylobia anthropophaga (1). The prevalence is higher in the tropical and subtropical zones than in other regions, so in the United States and in Europe the cases reported are mainly found in travelers returning from above mentioned destinations (1). In moderate climate larvae of cosmopolitan flies diptera are accidental parasites in human skin – Hypoderma bovis, Gasterophilus intestinalis; nose, paranasal sinuses, pharynx, ears - Calliphora sp., Lucilia sericata, Musca domestica; alimentary tract and urogenital system - Fannia canicularis; eyes, orbits, periorbital tissue - Calliphora vicina, H. bovis.
Blowflies (Calliphoridae) are found worldwide and they can cause myiasis of relatively short duration, by both obligatory and/or facultative parasites, which mature within 4-7 days, usually at the host’s body orifices and in wounds; they must for a certain period feed on the host’s tissue, liquid body substances or ingested food (Bhatt).The fly may even drop its eggs in flight on the skin, wounds, or natural openings of an immobile person. The larvae pass through 3 stages before wandering from the lesion and dropping to the ground where they pupariate. The time required to complete the life cycle from egg to adult takes usually about 4-6 weeks. Myiasis can be classified as: accidental (larvae ingested along with food produce infection), semi specific (larvae are laid on necrotic tissue in wounds) and obligatory (larvae affect undamaged skin) (2).
The symptoms and signs depend on affected organs. Patients mainly complain of boil-like, painful, pruritic and tender lesions with the sense of something moving; sometimes they have fever, swollen glands and headache.
From the literature it can be seen that the hosts are, on average, 60 years old, with a male : female ratio of 5,5:1; with homelessness, alcoholism, psychiatric diseases, mental disturbances and peripheral vascular disease being frequent cofactors (3, 4). Cases of neonatal myiasis have also been reported (5).
In available literature we have found only a few papers concerning ear myiasis caused by Lucilia sericata (2,3, 6-9), ex. in the United States between 1960-1995 only 4 cases (10), in Poland – 1 (11).
It should be underlined that infestation of the ears can be dangerous, because of the possibility of larvae penetration into the brain, which occurs in about 8% of such cases.
We report 2 cases of ear myiasis, observed in the same time, caused by Lucilia sericata larvae.
CASES REPORT
Case No 1. A 57 year-old man was admitted to ENT Department of Provincial Specialistic Hospital in Zgierz. He was a resident of the convalescence home of MONAR (Polish Organization Counteracting Addiction), but 4 weeks before admission to hospital he had left it of his own accord and became homeless; he slept in the forest. During admission to the hospital the patient was dirty and untidy. He complained of otalgia, fetid otorrhea, itching, bleeding. His left auricle was deformed with perforation and ulceration of the congested skin, upper part of the auricle cartilage was lost and became uncovered; the whole auricle and external auditory meatus were filled with fly larvae (fig.1-2). All larvae were carefully removed (fig.3) and placed into 3% formaline for further examination. Because of lack of part of auricular cartilage, skin of auriculae was cut off in local anesthesia; healing of the wound was correct (fig.4). The patient got an antiseptic dressing and received a prophylactic antibiotic therapy to prevent secondary infections. In a good condition he left the hospital. During 6 weeks of follow up no larvae were detected.
Case No 2. A 44 year- old woman was admitted to the Department of Head and Neck Neoplasms Surgery, Medical University of Lodz with a carcinoma of middle ear which was treated by radio- and chemio-therapy; during follow up visit otorhea was found, and the patient complained of aural fullness, otalgia, feeling of foreign body. During an examination a number of living larvae filling the destroyed pyramid of temporal bone were detected. All larvae were carefully removed manually and surgical debridement of devitalized tissue was performed. After the removal, antiseptic dressing was applied. Larvae were placed into 3% formaline for further examination. The patient didn’t get any local or systemic treatment. During 3 months of follow up no new larvae were detected.
The maggots collected in both cases were then indentified according to the key and description given in monography of Polish Calliphoridae (12) and the key prepared for forensic entomology applications (13). Probably due to conservation in 3% formaldehyde, their external diagnostic features were difficult to examine, as their cuticle was swollen and detached from the body. Because of deformation of papillae surrounding spiracular field and the field itself, it was impossible to estimate the distance between papillae and spiracular distance factor. For this reason, several specimens were prepared for microscopic examination, by dissolving in 10% KOH. The microscopic slides showing cephaloskeleton, anterior and posterior spiracles and spines of thoracic segments have been made.
In all cases, oral sclerite was unclerotised and there were no sclerotised area below posterior tip of ventral cornua. The anterior spiracles were divided into 7-10 lobes. The slits of posterior spiracles were linear, surrounded by thin, complete peritrema. The shape of spines of thoracic segment II was congruent with description and illustrations given in keys. On the basis of features mentioned above, all the maggots have been identified as 3rd stage larvae of Lucilia sericata Meigen (Diptera: Calliphoridae), the most common species causing otomyiases in Central Europe.
DISCUSSION
Myiasis usually occurs in neglected chronic lesions, especially among patients with poor hygiene, like in our case no.1; case no 2 is unique because it occurred in a patient with no hygienic or socioeconomic risk factors conductive to egg deposit or larvae growth (1). Myiasis in humans may be asymptomatic or severe and life threatening infection, when infestations of the eye, nose and ears penetrate into the brain (15).
The aural myiasis can give different signs and symptoms: larvae in the ear, otalgia, fetid otorrhea, aural fullness, perforation of the tympanic membrane, bleeding, itching, roaring sound, tinnitus, vertigo and furuncle of external auditory canal (2, 14, 16). The injury of the auditory meatus can lead to deafness and meningitis.
Maggots separate the necrotic tissue from the living tissue and for these reason they are used in “biosurgery”. “Biosurgery” it is induced by continuous flushing or irrigation of the wound by the copious exudates formed by the host in response to the maggots, killing, ingestion and digestion of bacteria by the maggots, secretion of allantoin, the rapid formation of granulation tissue stimulated by the continuous larval movement in the wound, liquefaction of necrotic tissue by the maggots and maggot extracts stimulating significant increases in total human fibroblasts.
In the case of aural myiasis early intervention will allow to avoid complications. Surgical removal of larvae with local anesthesia (lidocaine) is the most important procedure which should be undertaken; toothed forceps can be used. Intervention should be done so as to avoid lacerating the larvae because retained larval parts may lead to foreign body reaction. After the removal, antiseptic dressings are advised; antibiotics should be administered only if secondary infection is noted. If such procedure is not sufficient occlusion including petroleum jelly, liquid paraffin, beeswax, hair gel or heavy oil is used; also lard or bacon strips placed over the central punctum have been used to coax the larva to emerge spontaneously head-first over the course of several hours, at which time, tweezers (or forceps) aid in capturing them. Occlusion may occasionally result in asphxiation of the larva without inducing it to emerge and the retained larva may elicit an inflammatory response with the formation of foreign body granuloma and calcification of it. Systemic and/or topical treatment includes oral administration of ivermectin (200 μg/kg/24h per os) or topical use of it (1% solution) (1).
It must be kept in mind, that larvae should be killed by immersion for 30 seconds in very hot (>800 C, but not boiling) water, which prevents decay and maintains the natural color; then they should be preserved in a solution of 70% to 95% ethanol; formalin solutions should not be used, because they cause excessive hardening of the larval tissues, making them difficult to identify.
CONCLUSIONS
1. Larvae of cosmopolitan flies can induce human parasitosis which can be in the scope of ENT specialists.
2. Clinicians must have a clinical suspicion of aural myiasis not only to patients traveling to warm, humid climates or living in poor hygienic conditions, but also in moderate climate with no hygienic or socioeconomic risk factors.
3. Treatment includes manual removal of larvae, local and systemic drugs.
4. For the exact identification larvae should be killed by immersion in very hot water and preserved in a solution of 70% to 95% ethanol.
REFERENCES
1. Grammatikopoulou E, Wilson BB. 2009. Myiasis. E-medicine.
2. Yuca K, Caksen H, Sakin YF, Yuca SA, Kiris M, Yilmaz H, Cankaya H. 2005. Aural myiasis in children and literature review. Tohoku J Exp Med. 206:125-130.
3. Chigusa Y, Shinonaga S, Matsumoto J, Kirinoki M, Otake H et al. 1999. Aural myiasis due to Lucilia sericata (Diptera: Calliphoridae) in a patient suffering from diabetes, hypochondriasis and depression. Med Entomol Zool. 50: 295-297.
4. Maturo S, Michaelson PG, Horlbeck D, Brennan J. 2007. Auricular myiasis. Otolaryng Head Neck Surg. 138: 668-669.
5. Jain S, Audhya A, Nagpure PS. 2008. Aural myiasis in a 1 day old neonate. Indian J Med Sci. 62:164-165.
6. Yaghoobi R, Tirgari S, Sina N. 2005. Human auricular myiasis caused by Lucilia sericata: clinical and parasitological considerations. Acta Med Iranica, 43:155-157.
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9. Cho JH, Kim HB, Cho CS, Huh S, Ree HI. 1999. An aural myiasis case in a 54 year-old male farmer in Korea. Korean J Parasitol. 37: 51-53.
10. Sherman RA. 2000. Wound myiasis in urban and suburban United States. Arch Intern Med. 160: 2004-2014.
11. Sokołowski Z, Woźniak S. 1969. A case of infestation of a postoperative cavity within the ear by larvae of the fly. Wiad Lek. 22: 281-283.
12. Draber-Mońko A. 2004. Calliphoridae, Plujki (Insecta: Diptera). Fauna Poloniae 23, Warszawa; 659.
13. Szpila K. 2010. Key for the Identification of Third Instars of European Blowflies (Diptera: Calliphoridae) of Forenscic Importance. In: Amendt J. Lee Goff, M. Campobasco CP. Grassberger M. Curent Concepts in Forensic Entomology. 43-56.
14. Sood VP, Kakar PK, Wattal BL. 1976. Myiasis in otorhinolaryngology with entomological aspects. J Laryngol Otol. 90: 393-399.
15. Caça I, Satar A, Unlü K, Sakalar YB, Ari S. 2006. External ophthalmomyiasis infestation. Jpn J Ophthalmol. 50 (2): 176-7.
16. Hatten K, Gulleth Y, Meyer T, Eisenman DJ. 2010. Myiasis of the external and middle ear. Ann.Otol.Rhinol.Laryng.119 (7): 436-439.
FIGURE LEGENDS
Patient No 1:
A. auricula and external auditory meatus filled with fly larvae
B. after surgical removal of larvae
C. follow up (6 weeks)
D. removed larva