REVIEWARTICLE

Oral myiasis: case report and review of literature

Pramod Kumar & Virendra Singh

Received: 18 October 2012 /Accepted: 31 October 2012 /Published online: 20 November 2012# Springer-Verlag Berlin Heidelberg 2012

AbstractIntroduction The term myiasis is applied to the injuriousaction that larvae of certain Diptera cause in vertebrateanimals by growing in living or dead tissue. Because of itsgreat destructive potential, appropriate and preventive treat-ment is necessary. Oral myiasis is a rare pathology inhumans and is associated with poor oral hygiene, alcohol-ism, senility, suppurating lesion, severe halitosis, and otherconditions.Method We have presented a case of oral myiasis in amentally challenged patient.Results Reviewing the literature revealed that most of thecases involved the anterior part of the oral cavity of malepatients living in developing or underdeveloped countriesand also that predisposing factors invariably accompaniedinfestation.

Keywords Myiasis . Infestation . Humans

Introduction

Oral myiasis has been a rarely described condition, eventhough it was first mentioned in literature by Laurence in1909 [1]. Myiasis is an infestation of living humans andvertebrate animals with dipterous larvae which, at least for atime, feed on living or dead host tissue, liquid body sub-stances, or undigested food. Myiasis frequently occurs inrural areas, affecting livestock and pets such as dogs and

cats. In humans, it prevails usually in unhealthy individualsmainly from developing and underdeveloped countries[2–4] and uncommonly in the western developed world[5]. Many cases go unreported as a result of “cultural, socialand medico-political reasons” [6].

Myiasis is caused by members of the Muscidae fly familythat lay eggs or larvae on food, necrotic tissue, open wounds,unbroken skin, or mucosa. The classification of myiasis isbased on their localization on the host body (dermal, subder-mal, nasopharyngeal, internal organs, and urogenital [7]) or, inparasitological terms, on the type of host–parasite relationship(obligatory, facultative, or pseudomyiasis). Clinically, theycan also be classified as primary myiasis caused by biopha-gous larvae feeding on living tissue and is rare in humans. Themost common type in humans is the secondary variety causedby necrobiophagous flies feeding on dead tissue in a necroticcavity or lesion [8, 9]. Depending upon the condition ofinvolved tissue, myiasis can also be classified into accidental(larvae ingested along with the food), semispecific (larvae laidon necrotic tissue in wounds), and obligatory (larvae affectingthe undamaged skin).

In this article, we have reviewed oral myiasis by search-ing PubMed for publications. Only articles with sufficientinformation and data are reviewed here to draw any con-clusions (Table 1). A case report is presented to draw atten-tion towards neglect of these patients in poor socioeconomicclasses.

Case report

A mentally challenged bedridden 18-year-old female wasbrought by her relatives who had seen “worms” inside theoral cavity of the patient. The patient belonged to an econom-ically backward community of an isolated Indian village withno medical facilities . On examination, it was noted that fewmaggots were peeking from inside a traumatic wound, located

P. Kumar (*)Army Dental Corps, C/O 56 APO,Bathinda, Indiae-mail: prm2525@gmail.com

V. SinghDepartment of Oral and Maxillofacial Surgery, GDC, PGIMS,Rohtak, Haryana, India

Oral Maxillofac Surg (2014) 18:25–29DOI 10.1007/s10006-012-0373-2

Tab

le1

Caserepo

rtsreview

edfrom

theliterature

Species/references

Patient

age/sex

Country

Num

ber

oflarvae

Underlyingdisorder

Locationof

lesion

Methodof

treatm

ent

Other

antib

iotics

Sarcoph

agi[2]

9/F

Iran

3None

Gingiva

anterior

maxilla

Mechanicalremoval

None

Oestrus

ovis(O

estriae)

[10]

3/M

Iran

5None

Gingiva

anterior

maxilla

Mechanicalremoval

None

Cochilio

mia

hominivorax

(Callip

horidae)

[11]

20/F

Brazil

Multip

leHypotonic

cerebral

palsy

Gingiva

anterior

maxilla

Ivermectin

Cefalotin

Cochilio

mia

hominivorax

(Callip

horidae)

[12]

66/F

Brazil

40Adv

ancedperiod

ontal

disease,chronic

alcoholism

Gingiva

anterior

maxilla

Mechanicalremoval

None

Sarcoph

agi[13]

24/M

Brazil

Multip

leAfter

extractio

nGingiva

anterior

maxilla

Mechanicalremoval

None

Not

mentio

ned[14]

34/M

Brazil

55Neurologicdeficit,op

enbite,mouth

breathing,

poor

oral

hygiene

Gingiva

anterior

maxilla

Mechanicalremoval

None

Cochilio

mia

hominivorax

[15]

a.22

/MBrazil

24Dentalextractio

nMaxillarytoothextractio

nsocket

Ivermectin

,mechanical

remov

alCefazolin,

metronidazole

b.65/M

Not

mentio

ned

Senile,dependent,mouth

breather

Maxillarypalatalregion

Ivermectin

Non

e

Not

mentio

ned[16]

32/M

Brazil

Multip

leAlcohol

dependent,

poor

oral

hygiene

Upper

lipIvermectin

,mechanical

remov

alNon

e,checkgentian

violet

Noparasitological

exam

ination[17]

65/M

Brazil

9Cancrum

oris

Right

side

offace

Treatmentforcancrum

oris,mechanical

debridem

ent

Amox

icillin

and

clavulanic

acid

Cochilio

mia

hominivorax

(Callip

horidae)

[18]

5/F

Brazil

2Incompetent

lips,

malocclusion,

poor

oral

hygiene

Palatal

ging

ivamaxillary

anterior

Mechanicalremov

alAmox

icillin

Musca

domesticus

(Muscidae)

[19]

12/M

India

3Learningdisability,

incompetent

lips,

poor

oral

hygiene

Gingiva

anterior

mandible

Mechanicalremoval

None

Musca

domesticus

(Muscidae)

[20]

45/M

India

Multip

leMalno

urished,

mandibularfracture

Lips,floorof

mou

thTurpentineoil,mechanical

remov

alBroad-spectrum

antib

iotics,

metronidazole

Musca

nebulo

(Muscidae)

[21]

42/F

India

12Neurologicdeficit,trauma,

malocclusion,

period

ontal

disease

Gingiva

anterior

maxillary

Turpentineoil,ivermectin

,mechanicalremov

alNon

e

Chrysom

abezziana

(Callip

horidae)

[22]

89/F

Hon

gKon

g7

Bedridden

afterstroke,

nasogastricfeedingtube,

pulm

onaryTB

Gingiva

anterior

maxilla

Mechanicalremoval

Antibioticsforother

cond

itions

Woh

lfahrtia

mag

nifica

(Sarcophagidae)[23]

19/M

Israel

2None

Gingiva

posteriormandible

Mechanicalremoval

None

Not

mentio

ned[25]

12/F

Oman

8Spasticcerebral

palsy,

incompetent

lips,

anterior

open

bite,

poor

oral

hygiene

Maxillarypalatalregion

Mechanicalremoval

Antibioticsfor

pneumonia

Not

mentio

ned[25]

20/F

Oman

9Cerebralpalsy,bedridden,

malno

urished

Maxillarypalatalregion

Mechanicalremoval

Antibioticsfor

system

iccond

ition

26 Oral Maxillofac Surg (2014) 18:25–29

in the anterior maxillary vestibule region (Fig. 1). In general,oral hygiene was poor with incompetent lips and mouthbreathing. The patient lived in unhygienic conditions, oftenkept in the open near animals and unattended. Using a suffo-cation technique with turpentine oil, the extraction of livingmaggots was done with tweezers under local anesthesia(Fig. 2). The wound was debrided, irrigated with normalsaline, and closed on the second day after inspection. Theparasitological report identified the larvae asMusca domesticaor common housefly. The patient was followed for 3 months,and no fresh episode was seen.

Discussion

When the tissues of the oral cavity are invaded by theparasitic larvae of flies, the oral pathologist names thiscondition oral myiasis. The incidence of oral myiasis com-pared to that of cutaneous myiasis is low as oral tissues arenot permanently exposed to the external environment.

At least 86 different species of Diptera can infect manwith larvae that invade skin and body cavities [10]. Fleshflies exist worldwide and are found in a variety of environ-mental conditions, and the history of travel to an endemicarea by a healthy individual should be kept in mind whilemaking a diagnosis. The number of larvae present in variousreports ranges from few [2] to multiple [11–16] dependingon viable eggs deposited by flies which may be in the rangeof a few hundreds. This in turn will determine the extent ofhost damage. The fly can directly lay eggs on its host ordeliver them to the host by laying them on a vector such as abloodsucking arthropod. Warm and humid conditions of thetropics and subtropics with poor hygiene and lack of

medical care allow flies to breed freely and target suscepti-ble individuals freely. This problem can be identified as themajority of these reports are from developing [2, 10–21]countries and less for developed [22, 23] nations.

The life cycle of M. domestica starts with a female flylaying up to 500 eggs in several batches of about 75 to 150eggs. Eggs hatch within 10–24 h in warm weather. Thelegless maggots feed on decomposing tissues and gothrough three instars to reach full size in 5 days. The maturelarvae are 3 to 9 mm long, creamy white in color, cylindri-cal, with a tapering head. The fully developed larva leavesthe tissues to find a cooler drier environment in which topupate. The pupal stage generally lasts a further 5 days. Theemerging fly escapes from the pupal case through the use ofan alternately swelling and shrinking sac, called the ptilinumon the front of its head, which it uses like a pneumatichammer [24].

Although all age groups may be affected, the damagecaused to infants is more serious and may be fatal [4,23–28]. Most of the published reports involved male patientsprobably due to poor oral hygiene, neglect, increased outdoorwork, or travel to endemic areas when compared to females[10, 13–17, 19, 20, 23]. Also, the anterior part of the oralcavity was more commonly affected than the posteriorbecause it is easily accessible to flies [2, 10–16, 18–23, 25].

Oral myiasis is very rare in healthy growing children andadults [4]; most of the cases described in literature weresecondary to medical or anatomical conditions such as mal-nourished patients [17], neglected fractures [20], cerebralpalsy [8], mouth breathing [14, 15], anterior open bite [14,25], cancrum oris [17], poor oral hygiene [12, 14, 16,18–21, 25], mechanical ventilation [29], patient undergoingradiotherapy [30], person living in close proximity to ani-mals [10], and debilitated patient with neglect of nursing orcustodial personnel [31]. The female patient in our case wasmentally challenged with very poor oral hygiene and mouthbreathing habit. Most likely, she suffered from undiagnosedtrauma, and lack of care in a fly-abundant environment ledto infestation by flies. The diagnosis of myiasis at an earlyFig. 1 Traumatic wound and maggot infestation

Fig. 2 Extracted larvae

Oral Maxillofac Surg (2014) 18:25–29 27

stage can prevent involvement of deeper tissues. This isespecially important in individuals with a low socioeconom-ic level that may be unaware of the oral lesions [19, 25, 32].Moreover, a lack of regular oral care in these patients maycause the lesions to go unnoticed until extensive involve-ment occurs.

Even though myiasis may be self-limiting and nonfatal insome cases, the patient and relatives report with huge psycho-logical distress. Few larvae can destroy vital tissues, inducingserious or even life-threatening hemorrhage [11]. Surgicaldebridement of the wound and extraction of larvae are mostcommonly done under local anesthetic or general anesthesia.The occlusion or suffocation approach forces aerobic larvae tosurface in search of air where they can be removedwith the aidof forceps or tweezers [33]. Some of the agents that have beenused to suffocate are petroleum jelly, heavy oil, beeswax, rawmeat, mineral oil, nail polish, adhesive tape, butter, chewinggum, turpentine oil [20], whitehead varnish [22], native to-bacco leaf [33], chloroform, and ether [34]. In our patient, weused a cotton bud impregnated with turpentine oil which wasplaced at the orifice of the socket for approximately 10 min,forcing the larvae to come to the surface in search of oxygen,making extraction easy. Secondary infection of the wound bybacteria is uncommon because of the bacteriostatic activity inthe gut of larvae, preventing undesirable overgrowth of pyo-genic bacteria [35]. Systemic antibiotics are only necessarywhen secondary infection is known to be present [22, 25].

Recently, topical and oral ivermectin have been usedagainst maggots in humans [14–16]. Ivermectin is a semi-synthetic macrolide given orally in just a single dose of150–200 μg/kg body weight. It is assumed that ivermectinblocks nerve impulses to the nerve endings through therelease of gamma aminobutryic acid, linking to the receptorsand causing palsy and death of maggots.

According to Rossi-Schneider et al. [14], human my-iasis prevention involves fly population control, generalcleanliness, and informing the public that individualsliving in localities without basic sanitation are morepredisposed to infestation. Limiting myiasis directlyrelates to curbing the fly population by efficient wastedisposal supplemented by spraying with an insecticide,providing the patient with a physical barrier, and goodpersonnel and nursing care.

Prognosis, when there are no complications, is good.Although this is not a lethal disorder, knowledge of thisinfestation is necessary for a preventive, diagnostic, andcurative standpoint. Medical personnel dealing with suscep-tible patients must educate the patient, family members, andcaretakers about preventive measures.

Conflict of interest The authors declare that they have no conflictsof interest.

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