Not for the Squeamish
My first reaction about learning of myiasis was ... wow.
A rare occurrence in healthcare settings, myiasis is the infestation of maggots in mammals. Caused by eggs laid from female houseflies, the eggs grow to become maggots. The maggots live by ingesting living and necrotic tissue in the host. None of my nursing instructors had so much as mentioned this condition.
After learning an elderly patient, who presented in my facility with poor-healing wounds, had contracted myiasis, I wanted to learn more about it. I did a literature review of the condition. As a former nature museum docent, I knew about forensic application of insect identification. But I did not know insects such as houseflies could interfere with geriatric restorative care.
Myiasis can develop in a break in skin. Houseflies feed on various sources. Rotting food is a source, but flies are especially attracted to necrotic tissue and bodily fluids commonly found with purulent drainage within wounds.
Who's At Risk?
People at risk for contracting myiasis have co-morbidities. Those who are particularly at risk have limited mobility and a decline in mental capacity. Lacking the ability to perform self-care, bedridden patients are at risk due to incontinence.
Flies that commonly cause myiasis increase in number during the warmer months, so summer is the peak time for flies to reproduce and become pests. In healthcare facilities, it is common for patients and family to eat food in their room. Awaiting removal, open food is left on trays in the room. Discarded food lingers, if only for a short time, in trash receptacles near the patient. Flies are attracted to this.
If the female fly that causes myiasis is in the room, it will find a food source suitable for laying eggs. They are not picky eaters. So, the bedridden, immunocompromised patient is at risk for developing myiasis; if draining wounds or orifices such as the nares are not kept clean, there is an increased chance the fly will lay eggs in that area.
If the female fly lay eggs on broken skin such as a wound, the life cycle of the fly begins. After a few hours, the eggs hatch into larvae called maggots. The maggots are wingless, legless, eyeless and worm-like. As the maggots grow, the larval body changes and lengthens.
Maggots are nocuous because they eat living and necrotic tissues. The feeding on tissues can lead to infection and this can lead to sepsis. Redness and swelling is common; often the patient will complain of intense local pain and/or itching. Expect foul odor at the site.
The maggots will continue to eat and grow. Several days later, the maggots leave the host to complete maturation. Outside of the host, the maggots move to a dark, dry area to prepare for the next development stage: pupa. In the pupal stage, the maggot skin hardens and becomes dry and case-like. Inside, larvae metamorphose into flies. This life cycle is predictable: the hours and days for a fly to develop is temperature-dependent and calculable. So, the time of contraction with myiasis can be determined from the last stage of development when it was found in the host.
Nurses' Role in Treatment
Nurses are in a pivotal role to treat healthcare-associated myiasis. In nursing care, the goal of myiasis treatment is to remove the maggots and be a source of comfort to the patient. It is distressful to any person learning he or she is infested with maggots.
The nurse has to know the actions to take for treatment. Actions should be written in policy for the healthcare facility. At my facility, the VA in Baltimore, MD, the following steps are taken:
- First, contact the healthcare provider (NP, PA or physician).
- Second, using standard precautions, carefully remove the larva and preserve it by placing it in isopropyl (70 percent) alcohol within a leak-proof specimen container. This is important, as the preservative will assist the pathology lab with proper age calculation and identification of the species. Label the container with the patient's name, date and time you collected it and type of solution. Send this to the pathology lab immediately.
- Third, wipe the infected area using either sterile saline, hydrogen peroxide 3 percent or Dakin's solution (0.125 percent sodium hypochlorite). Next, soak the infected area for 20 minutes using 1 part hydrogen peroxide (3 percent) mixed with 4 parts sterile saline or sterile water. Dispose of soiled dressings and linens in proper receptacles. Determine the patient's immunization status of tetanus and diphtheroid; immunize the patient if needed. Document what was done. Locate protocol for room sanitation. One of the best practices for treating myiasis is prevention.
Prevention is multi-service; all services within the healthcare facility need to contribute efforts to prevent myiasis. Cover all wounds. Change wound dressings, particularly soiled ones, frequently. Remove of all open food containers and empty trash receptacles frequently. Discourage storage of foods at bedside. Maintain hygiene for nose, mouth and any orifice leading into the respiratory system. Rooms with open windows should have screens in the window frame. Keep facility doors closed.
Prior to becoming a RN, I volunteered as docent for an insect exhibit at a museum in the Chicago metro area. I learned flies can serve a beneficent role as a decisive factor in determining time of death in a body. Last month, I reencountered these insects at my extended-care facility. This time, I learned these same flies can complicate nursing care. Myiasis, host infested with maggots, can be pernicious in a patient who has poor health due to co-morbidities. Nurses are vital to treat and prevent myiasis.
Resources
Department of Veteran Affairs. Policy Memorandum, 512-11/COS IC-015, April 2008. VA Maryland Health Care System: The Infection Control/Hospital Epidemiology Program (111/MD). Retrieved from the World Wide Web: Aug. 5, 2009.
Couppie, P., Roussel, M., Rabarison, P., Sockeel, M.J., et al. (2005). Nosocomial nasal myiasis owing to ochilomyia hominivorax: a case in French Guiana. International Journal of Dermatology, 44, 302-303.
Sherman, R.A., Roselle, G., Bills, C., Danko, L.H., Eldridge, N. (2005). Healthcare-associated myiasis: prevention and intervention. Infectious Control and Hospital Epidemiology, 10, 828-832.
Szakacs, T.A., MacPherson, P., Sinclair, B.J., Gill, B.D., McCarthy, A.E. (2007). Nosocomial myiasis in a Canadian intensive care unit. Canadian Medical Association Journal, 177, 719-720.