What are the other Names for this Condition? (Also known as/Synonyms)

• Myiasis of Mouth
• Oral Cavity Myiasis

What is Oral Myiasis? (Definition/Background Information)

• Myiasis is primarily a skin disease caused by several species of parasitic fly larva (of taxonomic order Diptera). The fly larvae (maggots) cause disease in humans and other vertebrate animals by feeding on the tissues. The infection is usually characterized by a painful, itchy, boil-like skin lesion that contains the parasite within it
• Oral Cavity Myiasis or Oral Myiasis is a form of myiasis that develops in the mouth aided by factors such as poor oral hygiene, advancing age, mental illnesses, severe bad breath, and underlying dental health conditions such as severe gum disease. The parasites frequently causing the condition include warble flies (Hypoderma sp.), screw-worms (Wohlfahrtia magnifica), and houseflies (Muscidae sp.)
• Oral Myiasis can cause severe and extensive tissue destruction and serious complications, if not immediately addressed. Management of the condition involves removal of all larvae followed by surgical debridement of necrotic tissue. Nevertheless, the prognosis of Oral Myiasis depends on its severity; mild cases have better prognosis than severe cases

Who gets Oral Myiasis? (Age and Sex Distribution)

• Oral Myiasis may be observed in individuals of any age group
• Both males and females are affected, and no gender preference is noted
• Worldwide, individuals of all racial and ethnic groups may be affected. However, most of the cases are reported in tropical developing countries from Asia, Africa, and South America

What are the Risk Factors for Oral Myiasis? (Predisposing Factors)

There are a variety of risk factor for Oral Myiasis (mainly in the endemic regions). Often, a combination of risk factors may be observed. The predisposing factors include:

• Poor personal and oral hygiene along-with bad breath that attracts flies
• Old age
• Individuals who habitually breathe through their mouths while sleeping
• Individuals with congenital mouth defects that cause it to remain partly open
• Bad breath (halitosis) that may develop from various dental conditions
• Periodontitis (severe gum disease)
• Mouth ulcers
• Oral trauma wounds and jaw injuries that are left untreated
• Tooth extraction sites
• Mouth cancers
• Alcoholism and drug addiction
• Differently-abled people, especially those with mental disabilities
• Psychiatric illnesses: Elderly adults, especially those with certain neurodegenerative conditions
• Leprosy of the mouth
• Filariasis
• Uncontrolled diabetes
• Immunocompromised status
• Living in poverty and overcrowded unclean surroundings, low socioeconomic status
• Bedridden patients who cannot care for themselves
• Eating contaminated food items
• Rarely, infected mothers breastfeeding their children can cause Oral Myiasis in their children

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Oral Myiasis? (Etiology)

Oral Myiasis is a parasitic infection of the mouth caused by any of the following species of insect larvae:

• Blue bottle fly (Calliphora vicina)
• Giardia intestinalis, common intestinal parasite
• Houseflies (Musca sp.)
• New World screw-worm fly (Cochliomyia hominivorax)
• Old World screw-worm fly (Chrysomya bezziana)
• Sheep bot fly (Oestrus ovis)
• Spotted flesh fly or screwworm fly (Wohlfahrtia magnifica)
• Warble flies (Hypoderma sp.)

The parasitic insects either lay eggs or deposit their larvae in the mouth/oral cavity; up to 200 eggs may be laid by an adult fly. The condition may develop secondary to any medical/dental illness and/or aided by factors such as poor dental hygiene and lack of mental alertness. Individuals with chronically foul-smelling breath may also attract flies to their mouth.

What are the Signs and Symptoms of Oral Myiasis?

The signs and symptoms of Oral Myiasis may vary from one individual to another and may also depend on the type of causative larva species. In many individuals, the following may be noted:

• Localized pain
• Swelling of the mouth/mouth parts such as the lips, gums, or palate
• Presence of a lesion/ulcer that is aggravating and slowly increasing in size
• Bad breath
• Abscess formation; pus buildup in the mouth
• Foul-smelling discharge
• Severe tissue and bone loss
• Individuals can sense movement of the larva in their mouth

Additionally, systemic signs and symptoms, such as fever and chills, may be noted.

How is Oral Myiasis Diagnosed?

Oral Myiasis is diagnosed on the basis of the following information. The diagnostic techniques used may vary based on the specific type of causative parasite.

• Complete physical examination and a thorough medical history evaluation
• An oral specialist (dentist) will exam the mouth and assess the presenting signs and symptoms
• X-rays of the jaw, head, and neck area can be taken to detect the extent of bony involvement, which is caused by the inflammation
• An MRI scan or CT scan of the head and neck region
• Laboratory tests: Blood tests, such as complete blood count and peripheral blood smear

A differential diagnosis to eliminate other conditions/infections may be considered, before arriving at a definitive diagnosis. These may include:

• Inflammatory exophytic lesions such as pyogenic granuloma
• Inflammatory gingivostomatitis
• Malignancies involving the oral cavity (such as leukemia)
• Papillary inflammation
• Periodontal disease

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Oral Myiasis?

The complications of Oral Myiasis can be significant and may include:

• Severe emotional stress
• Severe pain and discomfort
• Secondary infection of the abscess; rupture of the abscess
• Perforation of the palate
• Loss of teeth
• Cellulitis: Skin infection that involves the deeper skin tissues
• Hypereosinophilia and leukocytosis (increased white blood cells)
• Severe inflammatory response to dead larvae or parts of larvae, especially during its removal
• Sepsis, which can be life-threatening

How is Oral Myiasis Treated?

The treatment for Oral Myiasis may involve the following measures:

• Use of turpentine/mineral/olive oil to manually extract the larvae
• The larvae may be also manually removed from the mouth using topical irritants, such as chloroform, iodoform, or using a mixture containing phenol, which helps immobilize the larvae
• Surgical extraction of the maggots may be undertaken by a dentist
• Surgical debridement of necrotic tissue
• Administration of broad-spectrum antibiotics
• Oral applications or medications containing ivermectin is known to be effective

Examination and identification of the larva following removal from skin tissues may be undertaken.

How can Oral Myiasis be Prevented?

Oral Myiasis may be prevented by considering the following measures:

• Maintain good oral hygiene
• Stopping smoking or chewing tobacco and substance abuse
• Periodically checking the mouths of children and individuals with special needs for detecting any early signs of gum disease or other dental health issues
• Controlling diabetes through lifestyle changes
• Early and prompt treatment of mild gum disease or any dental health conditions can help prevent periodontitis (the advanced stage of gum disease)
• Keep mouth closed while sleeping
• Stop drug abuse and limit alcohol intake
• Undertake prompt treatment of any oral ulcers/wounds and oral medical conditions
• Maintain basic personal and community hygiene and proper sanitation is highly important, particularly in the endemic zones
• Use insect repellents to prevent the insects from entering residences
• The growth of adult flies must be effectively controlled and methods for eradication followed on a regular basis

Undertake regular visits to a dental health professional for a proper dental check-up and to prevent/treat any tooth-related issues early.

What is the Prognosis of Oral Myiasis? (Outcomes/Resolutions)

The prognosis of Oral Myiasis may vary from one individual to another depending on its severity.

• The prognosis is normally good for localized cases with early adequate treatment
• Extensive tissue destruction and delayed/inadequate treatment may result in severe complications that may even be fatal
• In some individuals, rupture of an abscess containing the larva may lead to a severe inflammatory response

Additional and Relevant Useful Information for Oral Myiasis:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/healthy-living/skin-disorders/