Phycomycosis
From Wikipedia, the free encyclopedia
| ICD-10 | B46. |
|---|---|
| ICD-9 | 117.7 |
| DiseasesDB | 31329 |
Phycomycosis is an uncommon condition of the gastrointestinal tract and skin most commonly found in dogs and horses. The condition is caused by a variety of molds and fungi, and individual forms include pythiosis, zygomycosis, and lagenidiosis. Pythiosis is the most common type and is caused by Pythium, a type of water mould. Zygomycosis can also be caused by two types of zygomycetes, Entomophthorales (such as Basidiobolus and Conidiobolus) and Mucorales (such as Mucor, Mortierella, Absidia, Rhizopus, Rhizomucor, and Saksenaea).[1] The latter type of zygomycosis is also referred to as mucormycosis. Lagenidiosis is caused by a Lagenidium species, which like Pythium is a water mould.
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[edit] Pythiosis
Pythiosis is caused by Pythium insidiosum and occurs most commonly in dogs and horses, but is also found in cats, cattle, and humans. In the United States it is most commonly found in the Gulf states, especially Louisiana, but has been found in midwest and eastern states. It is also found in southeast Asia, eastern Australia, New Zealand, and South America. Pythium occupies swamps in late summer and infects dogs who drink water containing it. The disease is typically found in young, large breed dogs.[1]
The disease grows slowly in the stomach and small intestine, eventually forming large lumps of granulation tissue. It can also invade surrounding lymph nodes. Symptoms include vomiting, diarrhea, depression, weight loss, and a mass in the abdomen. Pythiosis of the skin in dogs is very rare, and appears as ulcerated lumps. Primary infection can also occur in the bones and lungs. In horses, subcutaneous pythiosis is the most common form and infection occurs through a wound while standing in water containing the pathogen.[2] In humans it can cause arteritis, keratitis, and periorbital cellulitis.[3] In cats pythioisis is almost always confined to the skin as hairless and edematous lesions. It is usually found on the limbs, perineum, and at the base of the tail.[4]
Pythium insidiosum is different from other members of the genus in that in addition to decaying plant tissue, human and horse hair, skin, and decaying animal tissue are chemoattractants for its zoospores.[2]
[edit] Zygomycosis
Zygomycosis usually is a disease of the skin, but can also occur in the sinuses or gastrointestinal tract. Zygomycosis caused by Mucorales causes a rapidly progressing disease of sudden onset in sick or immunocompromised animals. Entomophthorales cause chronic, local infections in otherwise healthy animals. The important species that cause entomophthoromycosis are Conidiobolus coronatus, C. incongruous, and B. ranarum. Conidiobolus infections of the upper respiratory system have been reported in humans, sheep, horses, and dogs, and Basidiobolus has been reported less commonly in humans and dogs.[5] Entomophthorales is found in soil and decaying plant matter, and specifically Basidiobolus can be contracted from insects and the feces of reptiles or amphibians.[3]
[edit] Lagenidiosis
The best known species of Lagenidium is Lagenidium giganteum, a parasite of mosquito larvae used in biological control of mosquitoes. A different species causes disease exclusively in dogs. Lagenidiosis is found in the southeastern United States in lakes and ponds. It causes progressive skin and subcutaneous lesions in the legs, groin, trunk, and near the tail. The lesions are firm nodules or ulcerated regions with draining tracts. Regional lymph nodes are usually swollen. Many dogs have spread of the disease to distant lymph nodes, large blood vessels, and the lungs.[3]
[edit] Diagnosis and treatment
Diagnosis is through biopsy, although an ELISA test has been developed for Pythium insidiosum in animals.[6] Treatment is very difficult and includes surgery when possible. Postoperative recurrence is common. Antifungal drugs show only limited effect on the disease, but itraconazole and terbinafine hydrochloride are often used for two to three months following surgery.[3] Humans with Basidiobolus infections have been treated with amphotericin B and potassium iodide.[5] For pythiosis and lagenidiosis, a new drug targeting water moulds called caspofungin is available, but it is very expensive.[3] Immunotherapy has been used successfully in humans and horses with pythiosis.[6] The prognosis for any type of phycomycosis is poor.
[edit] References
- ^ a b Ettinger, Stephen J.;Feldman, Edward C. (1995). Textbook of Veterinary Internal Medicine, 4th ed., W.B. Saunders Company. ISBN 0-7216-6795-3.
- ^ a b Liljebjelke, Karen A.; Abramson, Carley; Brockus, Charles; Greene, Craig E. (2002). "Duodenal obstruction caused by infection with Pythium insidiosum in a 12-week-old puppy". Journal of the American Veterinary Medical Association 220 (8): 1188-1191. Retrieved on 2006-08-22.
- ^ a b c d e Grooters, Amy M. (2003). "Pythiosis, lagenidiosis, and zygomycosis in small animals". The Veterinary Clinics of North America 33: 695-720.
- ^ Wolf, Alice (2005). “Opportunistic fungal infections”, August, John R. (ed.): Consultations in Feline Internal Medicine Vol. 5. Elsevier Saunders. ISBN 0-7216-0423-4.
- ^ a b Greene, Craig E.; Brockus, Charles W.; Currin, P.; Jones, Chris J. (2002). "Infection with Basidiobolus ranarum in two dogs". Journal of the American Veterinary Medical Association 221 (4): 528-532. Retrieved on 2006-08-22.
- ^ a b Hensel, Patrick; Greene, Craig E.; Medleau, Linda; Latimer, Kenneth S.; Mendoza, Leonel (2003). "Immunotherapy for treatment of multicentric cutaneous pythiosis in a dog". Journal of the American Veterinary Medical Association 223 (2): 215-218. Retrieved on 2006-08-22.
