Fungal Diseases

Aspergillus is a mold that is often found both inside and outside the home throughout the world. There are 2 forms of aspergillosis – sinonasal and systemic. Sinonasal aspergillosis causes signs of chronic nasal disease including nasal discharge, nasal depigmentation, and sneezing. Systemic aspergillosis commonly affects bone, vertebral end plates, CNS, kidneys, and lymph nodes.

Blastomycosis is an enzootic invasive fungal infection that more commonly affects dogs as compared with cats. Most infections occur east of the Rocky Mountains. Dogs that live close to water (river, creek, pond, lake) are at increased risk of infection. It often affects the lungs, eyes, skin, lymph nodes, and bones/joints.

Coccidioidomycosis, or Valley Fever, is an enzootic invasive fungal infection found in the arid western US. It more commonly affects dogs as compared with cats. Infection can be localized to the lung and associated lymph nodes or spread to other organs, which commonly include the bone, eyes, skin, CNS, and lymph nodes.

Cryptococcus is a yeast found worldwide. It more commonly affects cats as compared with dogs. Environmental risks include soil contaminated with bird droppings. Cryptococcosis can be localized to the head (nose, sinuses, skin, lymph nodes, eyes, CNS) or spread to any other organ in the body.

Histoplasmosis is an enzootic invasive fungal infection that more commonly affects cats as compared with dogs. Most infections occur east of the Rocky Mountains. Environmental risks include disruption of soil/dust contaminated with bird or bat droppings. Histoplasmosis can be localized to the lung and associated lymph nodes or spread to essentially organ in the body. In cats, eyes, lymph nodes, spleen, liver, and bone/joint are commonly affected. Dogs more often have GI tract involvement.

Invasive fungal infections often cause multisystemic disease including non-specific signs such as anorexia, weight loss, lethargy, and fever unresponsive to antibiotics. For some of the fungal pathogens there are specific non-invasive tests. For many there are not. For the latter, a broad non-invasive biomarker such as Beta-D-Glucan (BDG), might help support the diagnosis. Many opportunistic molds, enzootic dimorphic fungi, Pneumocystis, and even the fungal-like organism Pythium contains BDG in the cell wall.

Pythiosis, caused by Pythium, is a fungal-like infection affecting primarily dogs, but cats and other animals can also be infected. Pythiosis is found on multiple continents around the world and can be diagnosed anywhere in the U.S. Pythium likes warm temperatures and is most common in southern states.