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

• Genitourinary Tract Myiasis
• Myiasis of the Genitourinary Tract

What is Urogenital 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
• Urogenital Myiasis is a form of myiasis involving the urinary and genital organs (in the urogenital region) due to parasitic infection of fly larvae. Myiasis of the Genitourinary Tract can affect both males and females, and is classified into the following two subtypes based on whether the infection is superficial (involving the skin layers) or deep-seated (involving the organs):
  • External Urogenital Myiasis: It is a form of cutaneous myiasis with involvement of the skin and subcutaneous layers of the pelvic region. It is similar in presentation to furuncular myiasis or wound myiasis
  • Internal Urogenital Myiasis: It is described as an accidental myiasis where involvement of internal urogenital organs, such as the kidneys, urinary bladder, and reproductive organs, occurs from larval infestation
• Urogenital Myiasis can cause 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, if necessary. The prognosis depends on its severity and type; mild cases have better prognosis than severe cases

Who gets Urogenital Myiasis? (Age and Sex Distribution)

• Urogenital Myiasis is a rare fly larvae infestation of the urogenital region. The presentation of symptoms may occur at any age
• Both males and females are affected:
  • There is no gender preference in Internal Urogenital Myiasis
  • A female preference is noted in External Urogenital Myiasis
• Individuals of all racial and ethnic groups may be affected
• Geographically, the condition is observed in Asia, Africa, Central and South America, and Europe

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

The following risk factors are noted for Urogenital Myiasis: (mainly in the endemic regions)

• Living in or visiting the endemic regions
• Living in poverty and overcrowded unclean surroundings
• Poor personal hygiene
• Individuals who work outdoors, especially in forests such as wildlife conservationists, archaeologists, tourists, farmers and plantation workers, miners, etc.
• Contact with infected animals in the endemic regions
• Lack of quality healthcare in the endemic regions
• Elderly adults, especially those with certain neurodegenerative conditions
• Poor mental health
• Bedridden patients who cannot care for themselves
• Alcoholics
• Uncontrolled diabetes

External Urogenital Myiasis risk factors may additionally include:

• Sexually transmitted diseases
• Wearing wet clothes
• Using contaminated clothes (washed and dried outside) without ironing
• Having an open suppurating wound or ulcer
• The risk for women in the endemic regions is high from:
  • Not wearing underwear
  • Cervical cancer
  • Infections causing chronic (foul-smelling) urethral discharge
  • Placement of urethral stent
• Individuals with pre-existent skin diseases/conditions
• Migration of myiasis to urinary and genital region

Internal Urogenital Myiasis risk factors may additionally include:

• Poor toilet facilities
• Urinary tract infection
• Invasive procedures involving the genitourinary region
• Lack of treatment of cutaneous myiasis, especially those affecting the groin area

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 Urogenital Myiasis? (Etiology)

Urogenital Myiasis is a parasitic infection caused by the following insect larvae. The insects may lay their eggs or deposit larvae on the urethral openings, or open wounds/lesions in the region, and find their way into the genitourinary system.

• Causative agents for External Urogenital Myiasis:
  • African tumbu fly (Cordylobia anthropophaga)
  • House flies and stable flies (Muscidae sp.)
  • Human botfly (Dermatobia hominis)
  • Myiasis fly (Wohlfahrtia vigil)
  • New World screw-worm fly (Cochliomyia hominivorax)
  • Old World screw-worm fly (Chrysomya bezziana)
  • Rodent bots (Cuterebra sp.)
  • Spotted flesh fly or screwworm fly (Wohlfahrtia magnifica)
• Causative agents for Internal Urogenital Myiasis:
  • Cheese fly (Piophila casei)
  • Drone fly (Eristalis tenax)
  • False stable fly (Muscina stabulans)
  • Humpbacked fly or coffin fly (Megaselia scalaris)
  • Latrine fly (Fannia sp.) 
  • Psychoda albipennis - one of the most common causes of Urogenital Myiasis

It is important to note that many cases of Urogenital Myiasis have also been reported among children and adults of high socioeconomic standards, adequate hygienic conditions, with good toilet facilities.

What are the Signs and Symptoms of Urogenital Myiasis?

The signs and symptoms of Urogenital Myiasis may include the following:

External Urogenital Myiasis:

• Swelling and redness on the skin, including itchy groin
• Appearance of an enlarging skin lesion that is red and inflamed
• Severe pain and discomfort
• Abscess formation, with a white central plug-like spot (this spot often houses the live larva)
• Oozing of pus from abscesses or a clear fluid from the white plug
• Foul-smelling discharge
  • In females, the vulva, vagina, urethra, uterus, and clitoris may be affected
  • In males, the penis, scrotum, and urethra may be affected
• Individuals can sense movement of the larva within the lesion
• Fistula formation

Internal Urogenital Myiasis:

• Lower abdominal or back pain
• Painful or difficult urination
• Larvae or larval remnants may be observed as linear, wriggling, particulate matter in urine
• Urine may be dark or brown in color
• Obstruction of the urinary tract
• Urinary incontinence or involuntary urine leakage
• Frequent urination
• Inflammation of the genitourinary anatomical structures

How is Urogenital Myiasis Diagnosed?

Urogenital 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
• Assessment of signs and symptoms, including a visual examination of the lesion
• Laboratory tests: Blood tests, such as complete blood count, which may show increased white blood cells
• Urine analysis
• Imaging studies, as necessary: Ultrasound scan of the affected region to localize the larva and extent of involvement. This can help enable the surgeon to remove the larva without damaging the surrounding tissues
• Abdominal and pelvic CT scan
• Endoscopic imaging studies
• Kidney function test
• Intravenous pyelogram (IVP): A dye is injected into the blood vessels and the image of kidney structure is obtained

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

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 Urogenital Myiasis?

The complications of Urogenital Myiasis may include:

• Severe emotional stress
• Secondary infection of the abscess; rupture of the abscess
• Uterine prolapse (in women)
• Cellulitis: Skin infection that involves the deeper skin tissues
• Migration of maggots to other internal organs of the body
• Severe inflammatory response to dead larvae or parts of larvae, especially during its removal
• Sepsis, which can be life-threatening

How is Urogenital Myiasis Treated?

The treatment for Urogenital Myiasis may involve the following measures. However, generally the most effective way to treat myiasis is via surgery.

• For External Urogenital Myiasis:
  • Asphyxiating the larvae by plugging the central pore of a lesion with petroleum jelly or paraffin
  • Infusion of lesion with lidocaine and adrenalin to visualize the larval head, followed by removal of larva
  • Insecticides to kill the larva within the abscess
  • Manual removal of larvae
• For Internal Urogenital Myiasis:
  • Manual extraction of larva from the urinary tract after visualizing the same
  • Surgical extraction of the larva from affected region
• Surgical debridement of dead or necrotic tissue after removal of larvae
• Use of ivermectin topical applications
• Dressing and wound care, as required
• Administration of broad-spectrum antibiotics

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

How can Urogenital Myiasis be Prevented?

Urogenital Myiasis may be prevented by considering the following measures:

• Maintaining basic personal and community hygiene and proper sanitation is highly important, particularly in the endemic zones
• Extra care should be taken while travelling to tropical and sub-tropical areas
• 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
• Undertaking early treatment of sexually-transmitted infections and other urogenital conditions
• Try to cover all portions of the skin using long-sleeved shirts, full trousers, and socks to protect the body and skin from insect bites
• Use insect repellents to prevent the insects from entering residences
• Dry clothes in direct sunlight
• Iron clothes to help kill the eggs, which may have been laid on damp clothes
• Seek medical attention for any changes in skin; especially, after visiting known endemic regions
• The growth of adult flies must be effectively controlled and methods for eradication followed on a regular basis

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

The prognosis of Urogenital Myiasis is good, if the larva or larvae can be located and removed completely from the body.

• In many cases, the prognosis is good, since External Urogenital Myiasis is a self-limited condition that resolves completely with adequate treatment.
• A lack of early diagnosis and/or treatment of Internal Urogenital Myiasis can result in severe complications
• In some individuals, rupture of an abscess containing the larva may lead to a severe inflammatory response 
• Additionally, life-threatening sepsis may occur due to secondary infections

Additional and Relevant Useful Information for Urogenital Myiasis:

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

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