Phycomycosis is a disease that can be caused by a wide range of molds and fungi. A number of Phycomycosis variations have gotten their own names, such as Pythiosis, Lagenidiosis and Zygomycosis. Dogs and horses are among the most commonly infected animals when it comes to Phycomycosis, but humans can also be infected with several forms of Phycomycosis. Phycomycosis primarily infect the gastrointestinal tract or the skin of a dog, but can spread to other parts of the body as well, including the lymph nodes.

In dogs, the most commonly found variant of Phycomycosis is Pythiosis. This disease is caused by a water mould called Pythium. Lagenidiosis is caused by a variety of Lagenidium species, which are water moulds just like Pythium. Zygomycosis can be caused by two different zygomycetes variants: Entomophthoralesand Mucorales. Among the many Entomophthorales variants you can for instance find Basidiobolus and Conidiobolus, while Absidia, Mucor, Mortierella, Saksenaea, Rhizomucor, and Rhizopus are examples of Mucorales varieties.

Since both Pythiosis and Lagenidiosis are diseases caused by micro organisms from the class Oomycetes, some veterinarians refer to both diseases as Oomycosis.

Pythiosis

You can read more about Pythiosis in this article here.

Zygomycosis

Zygomycosis in dogs normally affect the skin, but it can also infest the sinuses and the gastrointestinal tract of the dog. Mucorales organisms are quite frequent in dogs that are weakened by other forms of disease or that have a weak immune system. In these dogs, the disease normally comes with a sudden onset and then progresses very quickly.

Entomophthorales on the other hand, can attack even otherwise healthy animals. Entomophthorales live in the soil and among decaying plant tissue, and the dog can also contract the organism form feces from amphibians and reptiles. Insects can also spread this type of Phycomycosis. In reasonably strong dogs, this variant of Phycomycosis normally manifest in the form of local infections which can become chronic. Some dogs can develop infections in the upper respiratory tracts, and so can humans, horses and sheep. In horses, Phycomycosis often manifest in the form of lesions in the nose and mouth, sometimes combined with a runny nose and trouble breathing.

In severe cases, a Zygomycosis infection in the dog's sinus can spread from the sinus to the orbit and cranial vault, causing severe rhinocerebral mucormycosis.

In humans, Zygomycosis is not common in otherwise healthy individuals. The organisms can however be a serious problem for those suffering from HIV/AIDS or other problems with the immune system, and patients in acidosis (which can be caused by burns, diabetes etc). It can also affect elderly citizens. The risk for Zygomycosis is especially high when the skin or mucus membranes have been injured.

Lagenidiosis

Lagenidiosis in dogs is caused by a vast array of different Lagenidium species; all of them water moulds just like Pythium. Symptoms of Phycomycosis caused by Lagenidium species in dogs include progressive lesions on the skin and under the skin. They are primarily found on the legs of the dog, on the trunk, groin and close to the tail. The lesions are either in the form of firm nodules or appear as ulcerated regions with draining tracts. In addition to lesions, this type of Phycomycosis in dogs normally causes swollen lymph nodes. The lymphatic system can also act as a way for the disease to spread, infecting the lungs and the major blood vessels. The dog can die if an aneurysm of a major vessel ruptures.

The best know Lagenidium species is Lagenidium giganteum, since this organism is used to decrease the amount of mosquitoes in malaria infested parts of the world. Lagenidium giganteum is a parasite of mosquito larvae and is therefore valuable in biological control of mosquitoes. The Lagenidium species causing Phycomycosis in dogs is however another species, not Lagenidium giganteum.

Fungal Infections in dogs: (click for more info)
Blastomycosis in dogs
Cryptococcosis in dogs
Histoplasmosis in dogs
Phycomycosis in dogs
Pythiosis in dogs
Ringworm in dogs
Sporotrichosis in dogs