# Phycomycosis

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Medical condition

Phycomycosis Causes various species of fungi and oomycota

**Phycomycosis** is an uncommon condition affecting the [gastrointestinal tract](/source/Gastrointestinal_tract) and [skin](/source/Skin), most commonly found in [dogs](/source/Dog) and [horses](/source/Horse). The condition is caused by various [molds](/source/Mold_(fungus)) (a type of [fungi](/source/Fungus)), including pythiosis, zygomycosis, and lagenidiosis. Pythiosis, the most common type, is caused by *[Pythium](/source/Pythium)*, a type of [water mold](/source/Oomycete). Zygomycosis can be caused by two types of [zygomycetes](/source/Zygomycota): *[Entomophthorales](/source/Entomophthorales)* (e.g., *[Basidiobolus](/source/Basidiobolus)* and *[Conidiobolus](/source/Conidiobolus)*) and *[Mucorales](/source/Mucorales)* (e.g., *[Mucor](/source/Mucor)*, *[Mortierella](/source/Mortierella)*, *[Absidia](/source/Absidia)*, *[Rhizopus](/source/Rhizopus)*, *[Rhizomucor](/source/Rhizomucor)*, and *[Saksenaea](/source/Saksenaea)*).[1] The latter type of zygomycosis is also referred to as [mucormycosis](/source/Mucormycosis). Lagenidiosis is caused by a *[Lagenidium](/source/Lagenidium)* species, which, like Pythium, is a kind of water mold. Since both pythiosis and lagenidiosis are caused by organisms from the [Oomycetes](/source/Oomycete) and not the Fungi kingdom, they are sometimes collectively referred to as oomycosis.

## Pythiosis

Ulcerative and destructive skin lesion on a dog caused by Pythium insidiosum

Pythiosis is caused by *[Pythium insidiosum](/source/Pythium_insidiosum)* and occurs most commonly in dogs and [horses](/source/Horse), but is also found in [cats](/source/Cat), [cattle](/source/Cow), and humans. In the United States, it is most commonly found in states bordering the Gulf of Mexico, especially [Louisiana](/source/Louisiana), but has been found in the Midwest and Eastern states as well. It is also found in [Southeast Asia](/source/Southeast_Asia), eastern [Australia](/source/Australia), [New Zealand](/source/New_Zealand), and [South America](/source/South_America). Pythiosis occurs in areas with mild winters due to the organism surviving in standing water that does not reach freezing temperatures.[2] *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]

It is suspected that pythiosis is caused by the invasion of the organism into wounds, either in the skin or in the gastrointestinal tract.[2] The disease grows slowly in the [stomach](/source/Stomach) and [small intestine](/source/Small_intestine), eventually forming large lumps of [granulation tissue](/source/Granulation_tissue). It can also invade surrounding [lymph nodes](/source/Lymph_node). Symptoms include vomiting, diarrhea, weight loss, a mass in the abdomen, and depression. Pythiosis of the skin in dogs is very rare and appears as [ulcerated](/source/Ulcer) lumps. Primary infection can also occur in the bones and lungs.

*Pythium* hyphae

In horses, [subcutaneous](/source/Subcutis) pythiosis is the most common form. Infection occurs through a wound while standing in water containing the pathogen.[3] The disease is also known as leeches, swamp cancer, and bursatti. Lesions are most commonly found on the lower limbs, abdomen, chest, and genitals. They are [granulomatous](/source/Granuloma) and itchy, and may be ulcerated or [fistulated](/source/Fistula). The lesions often contain yellow, firm masses of dead tissue known as kunkers.[4] For cases with chronic infection, it is possible for the disease to spread to underlying bone.[5]

In cats, pythioisis is almost always confined to the skin as hairless and edematous lesions. It is usually found on the limbs, [perineum](/source/Perineum), and at the base of the tail.[6] Lesions may also develop in the [nasopharynx](/source/Nasopharynx).[4]

In humans, it can cause [arteritis](/source/Arteritis), [keratitis](/source/Keratitis), and [periorbital](/source/Periorbital) [cellulitis](/source/Cellulitis).[7]

*Pythium insidiosum* is different from other members of the genus in that human and horse hair, skin, and decaying animal tissue are [chemoattractants](/source/Chemoattractant) for its [zoospores](/source/Zoospore), in addition to decaying plant tissue.[3]

## Zygomycosis

For Basidiobolus infection in humans (basidiobolomycosis), see [Basidiobolus ranarum](/source/Basidiobolus_ranarum).

For Mucorales infection in humans, see [Mucormycosis](/source/Mucormycosis).

A mature [sporangium](/source/Sporangium) of a *Mucor* sp. fungus

Zygomycosis is most often a disease of the skin, but can also occur in the sinuses or gastrointestinal tract. In humans, it is most prevalent in immunocompromised patients (people living with [HIV/AIDS](/source/AIDS), the [elderly](/source/Old_age), people with [severe combined immunodeficiency](/source/Severe_combined_immunodeficiency), etc.) and patients with acidosis (i.e., diabetes, burns), particularly after barrier injury to the skin or mucous membranes. Zygomycosis caused by *Mucorales* causes a rapidly progressing disease of sudden onset in sick or [immunocompromised](/source/Immunodeficiency) animals. *Entomophthorales* caused chronic, local infections in otherwise healthy animals. The important species that cause entomophthoromycosis are *Conidiobolus coronatus*, *C. incongruous*, and *[Basidiobolus ranarum](/source/Basidiobolus_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.[8] Horses are one of the most common domestic animals to be affected by entomophthoromycosis. *C. coronatus* causes lesions in the nasal and oral [mucosa](/source/Mucous_membrane) of horses that may cause nasal discharge or difficulty breathing. *B. ranarum* causes large circular nodules on the upper body and neck of horses.[9] *Entomophthorales* is found in soil and decaying plant matter, and, specifically, *Basidiobolus* can be contracted from insects and the feces of reptiles or amphibians.[7]

Zygomycosis of the sinuses can extend from the sinuses into the orbit and the cranial vault, leading to rhinocerebral mucormycosis.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*]

## Lagenidiosis

The best known species of *Lagenidium* is *[Lagenidium giganteum](/source/Lagenidium_giganteum)*, a parasite of *mosquito* larvae used in the [biological control](/source/Biological_pest_control) of mosquitoes. Two different species exclusively cause disease in dogs: *L. caninum* and *L. karlingii*. *Lagenidium* is found in the Southeastern United States in lakes and ponds. Lagenidiosis 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](https://en.wikipedia.org/w/index.php?title=Draining_tract&action=edit&redlink=1). Regional lymph nodes are usually swollen. Spread of the disease to distant lymph nodes, large blood vessels, and the lungs may occur.[7] An [aneurysm](/source/Aneurysm) of a [great vessel](/source/Great_vessels) can rupture and cause death.[4] *L. caninum* is the more aggressive species and is more likely to spread to other organs than *L. karlingii*.[10]

## Diagnosis and treatment

Diagnosis is through [biopsy](/source/Biopsy), [culture](/source/Microbiological_culture) or an enzyme-linked immunosorbent assay ([ELISA](/source/ELISA)) test.[11] Treatment is very difficult and includes [surgery](/source/Surgery) when possible. Postoperative recurrence is common. [Antifungal drugs](/source/Antifungal_drug) show only limited effect on the disease, but [itraconazole](/source/Itraconazole) and [terbinafine hydrochloride](/source/Terbinafine) are often used for 2 to 3 months following surgery.[7] Humans with *Basidiobolus* infections have been treated with [amphotericin B](/source/Amphotericin_B) and [potassium iodide](/source/Potassium_iodide).[8] For pythiosis and lagenidiosis, a drug targeting water molds called [caspofungin](/source/Caspofungin) is available, although its high cost makes its usage to be rare.[7] [Immunotherapy](/source/Immunotherapy) has been used successfully in humans and horses with pythiosis.[11] The [prognosis](/source/Prognosis) for any type of phycomycosis is poor.

## References

1. ^ [***a***](#cite_ref-Ettinger_1995_1-0) [***b***](#cite_ref-Ettinger_1995_1-1) Ettinger, Stephen J.; Feldman, Edward C. (1995). *Textbook of Veterinary Internal Medicine* (4th ed.). W.B. Saunders Company. [ISBN](/source/ISBN_(identifier)) [0-7216-6795-3](https://en.wikipedia.org/wiki/Special:BookSources/0-7216-6795-3).

1. ^ [***a***](#cite_ref-Helman_2-0) [***b***](#cite_ref-Helman_2-1) Helman R, Oliver J (1999). "Pythiosis of the digestive tract in dogs from Oklahoma". *J Am Anim Hosp Assoc*. **35** (2): 111–4. [doi](/source/Doi_(identifier)):[10.5326/15473317-35-2-111](https://doi.org/10.5326%2F15473317-35-2-111). [PMID](/source/PMID_(identifier)) [10102178](https://pubmed.ncbi.nlm.nih.gov/10102178).

1. ^ [***a***](#cite_ref-Liljebjelke_3-0) [***b***](#cite_ref-Liljebjelke_3-1) Liljebjelke K, Abramson C, Brockus C, Greene C (2002). ["Duodenal obstruction caused by infection with Pythium insidiosum in a 12-week-old puppy"](https://doi.org/10.2460%2Fjavma.2002.220.1188). *J Am Vet Med Assoc*. **220** (8): 1188–91, 1162. [doi](/source/Doi_(identifier)):[10.2460/javma.2002.220.1188](https://doi.org/10.2460%2Fjavma.2002.220.1188). [PMID](/source/PMID_(identifier)) [11990966](https://pubmed.ncbi.nlm.nih.gov/11990966).

1. ^ [***a***](#cite_ref-Merck_oo_4-0) [***b***](#cite_ref-Merck_oo_4-1) [***c***](#cite_ref-Merck_oo_4-2) ["Oomycosis"](https://web.archive.org/web/20160303174059/http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm%2Fbc%2F51112.htm). *The Merck Veterinary Manual*. 2006. Archived from [the original](http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51112.htm) on 2016-03-03. Retrieved 2007-02-03.

1. **[^](#cite_ref-5)** Worster A, Lillich J, Cox J, Rush B (2000). ["Pythiosis with bone lesions in a pregnant mare"](https://doi.org/10.2460%2Fjavma.2000.216.1795). *J Am Vet Med Assoc*. **216** (11): 1795–8, 1760. [doi](/source/Doi_(identifier)):[10.2460/javma.2000.216.1795](https://doi.org/10.2460%2Fjavma.2000.216.1795). [PMID](/source/PMID_(identifier)) [10844973](https://pubmed.ncbi.nlm.nih.gov/10844973).

1. **[^](#cite_ref-Wolf_2005_6-0)** Wolf, Alice (2005). "Opportunistic fungal infections". In August, John R. (ed.). *Consultations in Feline Internal Medicine Vol. 5*. Elsevier Saunders. [ISBN](/source/ISBN_(identifier)) [0-7216-0423-4](https://en.wikipedia.org/wiki/Special:BookSources/0-7216-0423-4).

1. ^ [***a***](#cite_ref-Grooters_2003_7-0) [***b***](#cite_ref-Grooters_2003_7-1) [***c***](#cite_ref-Grooters_2003_7-2) [***d***](#cite_ref-Grooters_2003_7-3) [***e***](#cite_ref-Grooters_2003_7-4) Grooters A (2003). "Pythiosis, lagenidiosis, and zygomycosis in small animals". *Vet Clin North Am Small Anim Pract*. **33** (4): 695–720, v. [doi](/source/Doi_(identifier)):[10.1016/S0195-5616(03)00034-2](https://doi.org/10.1016%2FS0195-5616%2803%2900034-2). [PMID](/source/PMID_(identifier)) [12910739](https://pubmed.ncbi.nlm.nih.gov/12910739).

1. ^ [***a***](#cite_ref-Greene_8-0) [***b***](#cite_ref-Greene_8-1) Greene C, Brockus C, Currin M, Jones C (2002). ["Infection with Basidiobolus ranarum in two dogs"](https://doi.org/10.2460%2Fjavma.2002.221.528). *J Am Vet Med Assoc*. **221** (4): 528–32, 500. [doi](/source/Doi_(identifier)):[10.2460/javma.2002.221.528](https://doi.org/10.2460%2Fjavma.2002.221.528). [PMID](/source/PMID_(identifier)) [12184703](https://pubmed.ncbi.nlm.nih.gov/12184703).

1. **[^](#cite_ref-9)** ["Zygomycosis"](http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51118.htm). *The Merck Veterinary Manual*. 2006. Retrieved 2007-02-03.

1. **[^](#cite_ref-forum_10-0)** Todd-Jenkins, Karen (September 2007). "A new disease: clinically interesting for all the right reasons". *Veterinary Forum*. **24** (9). Veterinary Learning Systems: 18–20.

1. ^ [***a***](#cite_ref-Hensel_11-0) [***b***](#cite_ref-Hensel_11-1) Hensel P, Greene C, Medleau L, Latimer K, Mendoza L (2003). "Immunotherapy for treatment of multicentric cutaneous pythiosis in a dog". *J Am Vet Med Assoc*. **223** (2): 215–8, 197. [doi](/source/Doi_(identifier)):[10.2460/javma.2003.223.215](https://doi.org/10.2460%2Fjavma.2003.223.215). [PMID](/source/PMID_(identifier)) [12875449](https://pubmed.ncbi.nlm.nih.gov/12875449).

## External links

- [*Oomycosis: Pythiosis in the Dog, Horse and Cat and Lagenidiosis in the Dog*](http://www.vet.uga.edu/VPP/clerk/stephens/index.htm) [Archived](https://web.archive.org/web/20061230102512/http://www.vet.uga.edu/vpp/CLERK/stephens/index.htm) 2006-12-30 at the [Wayback Machine](/source/Wayback_Machine)

v t e Fungal infection and mesomycetozoea Superficial and cutaneous (dermatomycosis): Tinea = skin; Piedra (exothrix/ endothrix) = hair Ascomycota Dermatophyte (Dermatophytosis) By location Tinea barbae/tinea capitis Kerion Tinea corporis Ringworm Dermatophytids Tinea cruris Tinea manuum Tinea pedis (athlete's foot) Tinea unguium/onychomycosis White superficial onychomycosis Distal subungual onychomycosis Proximal subungual onychomycosis Tinea corporis gladiatorum Tinea faciei Tinea imbricata Tinea incognito Favus By organism Epidermophyton floccosum Microsporum canis Microsporum audouinii Trichophyton interdigitale/mentagrophytes Trichophyton tonsurans Trichophyton schoenleini Trichophyton rubrum Trichophyton verrucosum Other Hortaea werneckii Tinea nigra Piedraia hortae Black piedra Basidiomycota Malassezia furfur Tinea versicolor Malassezia folliculitis Trichosporon White piedra Subcutaneous, systemic, and opportunistic Ascomycota Dimorphic (yeast+mold) Onygenales Coccidioides immitis/Coccidioides posadasii Coccidioidomycosis Disseminated coccidioidomycosis Primary cutaneous coccidioidomycosis. Primary pulmonary coccidioidomycosis Histoplasma capsulatum Histoplasmosis Primary cutaneous histoplasmosis Primary pulmonary histoplasmosis Progressive disseminated histoplasmosis Histoplasma duboisii African histoplasmosis Lacazia loboi Lobomycosis Paracoccidioides brasiliensis Paracoccidioidomycosis Other Blastomyces dermatitidis Blastomycosis North American blastomycosis South American blastomycosis Sporothrix schenckii Sporotrichosis Talaromyces marneffei Talaromycosis Scedosporiosis Emmonsiosis Emmonsia parva Adiaspiromycosis Yeast-like Candida albicans Candidiasis Oral Esophageal Vulvovaginal Chronic mucocutaneous Antibiotic candidiasis Candidal intertrigo Candidal onychomycosis Candidal paronychia Candidid Diaper candidiasis Congenital cutaneous candidiasis Perianal candidiasis Systemic candidiasis Erosio interdigitalis blastomycetica C. auris C. glabrata C. lusitaniae C. tropicalis Pneumocystis jirovecii Pneumocystosis Pneumocystis pneumonia Mold-like Aspergillus Aspergillosis Aspergilloma Allergic bronchopulmonary aspergillosis Primary cutaneous aspergillosis Exophiala jeanselmei Eumycetoma Fonsecaea pedrosoi/Fonsecaea compacta/Phialophora verrucosa Chromoblastomycosis Geotrichum candidum Geotrichosis Pseudallescheria boydii Allescheriasis Basidiomycota Cryptococcus neoformans Cryptococcosis Trichosporon spp Trichosporonosis Zygomycota (Zygomycosis) Mucorales (Mucormycosis) Rhizopus oryzae Mucor indicus Lichtheimia corymbifera Syncephalastrum racemosum Apophysomyces variabilis Entomophthorales (Entomophthoramycosis) Basidiobolus ranarum Basidiobolomycosis Conidiobolus coronatus/Conidiobolus incongruus Conidiobolomycosis Microsporidia (Microsporidiosis) Enterocytozoon bieneusi/Encephalitozoon intestinalis Mesomycetozoea Rhinosporidium seeberi Rhinosporidiosis Ungrouped Alternariosis Fungal folliculitis Fusarium Fusariosis Granuloma gluteale infantum Hyalohyphomycosis Otomycosis Keratomycosis Phaeohyphomycosis

Classification D ICD-10: B46 ICD-9-CM: 117.7 MeSH: D020096 DiseasesDB: 31329

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Adapted from the Wikipedia article [Phycomycosis](https://en.wikipedia.org/wiki/Phycomycosis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Phycomycosis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.