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

• Hospital-Acquired Myiasis

What is Nosocomial 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
• Nosocomial Myiasis describes fly larva infestation taking place in a hospital setting due to inadequate healthcare quality, lack of best medical practices, and/or negligence. The condition is more common in some of the developing and underdeveloped regions of the world
• Individuals, who are bedridden or unconscious, temporarily confined in hospital beds due to injuries and fractures treated using sutures and pins, have feeding/breathing tubes inserted, and are immunocompromised, have a high risk for acquiring myiasis in a poor infrastructure healthcare setting
• Nosocomial Myiasis can cause severe tissue destruction and serious complications, if not immediately addressed. Management of the condition involves removal of all larvae followed by surgical debridement. Nevertheless, the prognosis depends on its severity; tissue destruction on a large scale may lead to mortalities

Who gets Nosocomial Myiasis? (Age and Sex Distribution)

• Nosocomial 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 from Asia, Africa, and South America

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

The following factors may predispose individuals to Nosocomial Myiasis in a healthcare environment of low standards: (mainly in the endemic regions)

• Bedridden patients who cannot care for themselves; those who develop bedsores
• Loss of consciousness; individuals in coma
• Surgical procedures
• Poorly-controlled diabetes
• Any medical condition that decreases one’s immunity
• Patients who use devices such as ventilators, urinary catheters, or intravenous catheters, 
• Injuries and fractures that require pins and needles, which create punctures in the body
• Use of feeding tubes and breathing tubes
• Individuals with any medical condition/infection that causes chronic skin lesions (with discharge of fluids and abscesses)
• Open wounds that are neglected

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 Nosocomial Myiasis? (Etiology)

Nosocomial Myiasis is a parasitic infection within a hospital setting that lacks sufficient facilities and amenities, or properly trained medical staff. The condition may be caused by any of the following species of insect larvae. 

• Flesh flies (Sarcophaga sp.) 
• Green bottle blow fly (Lucilia sericata)
• House fly (Musca domestica)
• Laboratory fly (Megaselia scalaris)
• New World screw-worm fly (Cochliomyia hominivorax)
• Secondary screwworm (Cochliomyia macellaria)

The parasitic insects either lay eggs or deposit their larvae in or near open/fresh wounds, infected orifices, inserted tubes, catheters, suture marks, via immobilized patient’s mouth/nose, etc. The transmission is aided by conditions such as inadequate healthcare facility, poorly-trained staff, unhygienic visitors to the patient, eating and drinking in the patient rooms, presence of rodents/rats in the vicinity, lack of fly-mesh screens in the windows/ventilators of hospital rooms, and a lack of education or healthcare awareness.

What are the Signs and Symptoms of Nosocomial Myiasis?

The signs and symptoms of Nosocomial Myiasis may vary from one individual to another and is based on the type of larva species, and the site of infection. The most common origin points of infection include surgical sites, pins and tubes insertion sites, urinary tract, and the lungs.

According to medical literature, the reported cases of infection include:

• Intestinal myiasis with signs and symptoms that include:
  • Stomach or abdominal pain
  • Nausea and vomiting
  • Blood in stool
  • Intestinal inflammation
• Nasal and nasopharyngeal myiasis with signs and symptoms that include:
  • Generalized facial pain
  • Severe irritation in the nose
  • Foreign body sensation in the nose
  • Congestion
  • Nosebleed
  • Foul-smelling nasal discharge
  • Hoarse voice
• Ocular myiasis with signs and symptoms that include:
  • Foreign body sensation in the eye
  • Redness and excessive tearing
  • Light-sensitivity
  • Mild or severe eye pain
  • Loss of vision
• Oral myiasis with signs and symptoms that include:
  • 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
• Tracheal and pulmonary myiasis with signs and symptoms that include:
  • Whooping cough
  • Blood in sputum
  • Nasal discharge that is foul-smelling
  • Chest pain
  • Respiratory distress
• Urogenital myiasis with signs and symptoms that include:
  • Appearance of an enlarging skin lesion that is red and inflamed
  • Severe pain and discomfort
  • Abscess formation, oozing of pus from abscesses
  • Foul-smelling discharge
  • Abdominal pain
  • Painful or difficult urination
  • Dark-colored urine

Additionally, systemic signs and symptoms, such as high-grade fever, chills, and muscle and joint pain may be noted.

How is Nosocomial Myiasis Diagnosed?

Nosocomial Myiasis is diagnosed on the basis of the following information. The diagnostic techniques used may vary based on the specific type of causative parasite, and the body site involved.

• Complete physical examination and a thorough medical history evaluation (including history of recent surgeries, invasive procedures undergone, etc.)
• Assessment of signs and symptoms, including a visual examination of the lesion, if present
• Laboratory tests: Blood tests, such as complete blood count and peripheral blood smear
• Imaging studies, as necessary
• Biopsy studies

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 Nosocomial Myiasis?

Complications due to Nosocomial Myiasis are dependent on the site and severity of the infection and the overall immune status of the individual. The complications of Nosocomial Myiasis can be significant and may include:

• Secondary infection of the abscess; rupture of the abscess
• 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
• In a susceptible individual, a prolonged infection usually results if the infection travels to the blood stream, causing blood poisoning (septicemia)

How is Nosocomial Myiasis Treated?

Nosocomial Myiasis that arise at surgical sites are managed with a combination of medication and surgical care. The treatment for Nosocomial Myiasis may involve the following measures:

• Surgical debridement of dead or necrotic tissue after removal of all larvae
• The larvae may be immobilized through oil and chloroform and then extracted
• Deep lesions may be irrigated with antiseptic solutions
• Regular dressing changes and wound care, as needed
• Prescription oral medications (usually ivermectin), based on healthcare provider’s evaluation
• Broad-spectrum antibiotics, as needed

Examination and identification of the larva following removal is important.

How can Nosocomial Myiasis be Prevented?

Nosocomial Myiasis may be prevented by considering the following measures:

• Ensure clean and hygienic surroundings in healthcare settings
• Have well-trained medical staff
• Adhere to the best medical practices
• Ensure that wounds and skin ulcers are properly treated and dressed/covered
• Medical centers should provide fly screens on patient area doors, windows, and ventilators (including duct filters)
• Pantry areas and food canteens must be separated from patient ward areas to minimize flies in patient areas
• Educate patients, patient caregivers, and visitors on basic hygiene, handwashing importance, and overall cleanliness
• Proper elimination of hospital wastes
• Maintain basic personal and community hygiene and proper sanitation is highly important

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

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

• The prognosis is generally good when the infection is diagnosed and treated early
• However, involvement of the vital organs and delayed diagnosis/treatment may result in complications that can be fatal

Additional and Relevant Useful Information for Nosocomial Myiasis:

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

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