Cryptococcosis

Cryptococcosis is a rare infectious disease caused by the fungus Cryptococcosis neoformans with similar signs, symptoms, and treatments as the blastomycosis fungal disease. Humans and dogs are both susceptible by inhaling infectious spores that are spread by the excrement of birds, especially pigeons. After the spores are inhaled, the organism spreads to other organs. Cryptococcus has a tendency to invade the nervous system.

Symptoms

• weight loss
• lethargy
• central nervous system problems showing with head tilt, black & forth eye movements (called nystagmus), paralysis of the facial nerve leading to inability to blink, incoordination, circling and seizures
• eye problems: hemorrhage in the retina and inflammatory disorders of the eye called chorioretinitis and anterior uveitis

In humans, the symptoms include confusion, dizziness, headaches, fever, skin rash, coughing, chest pain, weakness, and sleepiness. Humans with weakened immune systems are most at risk. Once the central nervous system is infected, the damage is permanent, but most often there is most often a fatal outcome. In humans, it maybe be months to years before the central nervous system is affected.

Cats are said to get cryptococcosis more often than dogs, especially cats who have weakened immune systems from feline leukemia virus or feline immunodeficiency virus infections. In cats, their symptoms become worse over weeks or months. The disease in cats may show up in only one organ, or in many. The first symptoms in a cat are usually sneezing, snorting, and a nasal discharge from an upper respiratory disease. Polyp-like masses may pro-trude from one or both nostrils. The cervical lymph nodes can be enlarged. Ulcers or lesions might appear on the cat's tongue or palate. Skin lesions will also appear, often on the cat's face. The central nervous system also becomes infected. Neurological signs may be mild to severe. Signs of central nervous system involvement in a cat include a change in temperament, depression, disorientation, paralysis, circling, seizures, and even blindness.

When dogs get cryptococcosis, they show severe disseminated disease involving multiple organs, eyes, and central nervous system. Dogs rarely have infected nasal cavities. Ocular lesions are common. Infected dogs usually have respiratory disease, but not always. Lesions can often be found on the dog's organs (kidneys, lymph nodes, spleen, and liver).

Progression & Diagnosis
Cryptococcosis is usually transmitted by inhalation of the spores, but it can also enter through the skin. Cryptococcosis is not normally contagious unless one is very immune supressed (such as a human with HIV). It affects the lungs, can cause pneumonia, and can spread into other organs.
For a diagnosis of cryptococcosis, sample needs to be collected from tissue or fluid (blood, spinal fluid, urine, sputum, lung washes). Chest x-rays can reveal the lung infection.

Treatment
Cryptococcosis can be treated with amphotericin B, flucytosine, itraconazole and fluconazole. Amphotericin B and flucytosine are often used in combination. A combination of ketoconazole and itraconazole has been effective in some experimentally infected cats, including animals with neurologic disease. (source (PDF))

Prevention
Avoiding soil, especially soil covered in pigeon droppings is one form of prevention. Pigeon droppings can remain infectious for up to TWO years! No vaccines are available.

Where is it?
Cryptococcosis appears to be much rarer than Blastomycosis. Kristiina mentioned in her story about Laika that cryptococcosis is "becoming more and more prevalent on Vancouver Island and has also been detected on the Lower Mainland just recently," with several cases so far in cats, dogs, and humans. It is far more prevalent in other parts of the world, including the U.S. (California), Australia, parts of South and Central America. Some forms of cryptococcosis are found in these tropical areas in the bark, plant debris, and in the aira around Eucalyptus trees. The west coast the disease organism is most commonly Cryptococcus gattii. In British Columbia, it has been isolated from several species of native trees and from forest soil. Cases of cryptococcosis usually occur sporadically, but there has definitely been an outbreak on Vancouver Island, especially on the east coast, since 1999. In 2001/2002, at least 45 confirmed cases in animals, and 50 cases in humans were reported on Vancouver Island. Most of the animals affected were immunocompetent animals.


Resources: Links and Photos

• Systemic Fungal Diseases in Dogs - Disease in Disguise: Blastomycosis, Cryptococcosis, Coccidioidomycosis (Valley Fever), Histoplasmosis, Lyme Disease and more...
• Cryptococcosis - in humans
• Cryptococcosis - comprehensive information for infection of dogs, cats, humans, and several other animals. PDF format
• Questions and Answers about Cryptococcal Disease - from the BC Centre for Disease Control - PDF format
• British Columbia: Multispecies outbreak of cryptococcosis on southern Vancouver Island, British Columbia - full text of a medical journal article
• CRYPTOCOCCUS UPDATE - JANUARY 2005 - an update from the Central Laboratory for Veterinarians