Infectious Diseases

Cryptococcus Gattii



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Cryptococcus gattii, or c. gattii, is a relatively new strain of airborne fungus affecting Canada's Vancouver Island since 1999, and more recently moving into the Northwest United States.  Before its discovery on Vancouver Island, it was believed to affect only tropical and sub-tropical regions of the world such as Australia and South America.  However, emerging cases of confirmed c. gattii infection in British Columbia and Oregon have shown that it has either spread to, or has just been laying dormant in those temperate regions. 

C. gattii is a fungal yeast infection which causes medical issues from pneumonia to meningitis, and can include multiple other life threatening symptoms.  Commonly, patients afflicted develop what are known as cryptococcomas.  A cryptococcoma is an infectious tumor caused by a living organism, in this case the c. gattii fungi.  These tumors are typically found in the brain, but have also been located in the lungs, eyes, prostate and elsewhere in the body.  This deadly disease affects not only humans, but has also been found in cats, dogs, birds, dolphin, llama and livestock.

To date, there have been around 50 known cases of c. gattii in the Northwest United States and of those about 10 patients have died (Doheny, 2010).  This is about 20% of those infected!  This shows that the U.S. strain is a particularly virile version of the British Columbia strain which has only killed 19 out of 218 patients, a death rate of 8.7%. 

Many deaths caused by c. gattii occur because doctors are generally unfamiliar with it and therefore it's often misdiagnosed as cryptococcus neoformans, a weaker cousin-fungus.  These misdiagnoses can lead to death because, although somewhat similar, c. gattii has a slower response to therapy thus requiring earlier treatment and results in more cryptococcomas which require surgery than c. neoformans.  Another peculiar difference between the two diseases is that c. neoformans is a typically opportunistic disease which affects mostly immunocompromised patients, such as those with HIV, rarely affecting immunocompetent (healthy) individuals.  C. gattii, on the other hand, primarily affects people with healthy immune systems.    

People become infected with c. gattii when they inhale infected microscopic organisms.  Lamentably, there's not anything which can be done to prevent inhalation.  Fortunately, although there are no known preventative measures which can aid in avoiding the disease, if caught early it does not need to be a death sentence.  Symptoms which could indicate you may have contracted c. gattii include a persistent cough, chest pains, headache, fevers and night sweats.  The presence of any of these symptoms indicate that you should see your doctor as soon as possible to get tested, especially if you've visited British Columbia or the Northwest in the last year.  Doctors can diagnose c. gattii through microscopic examinations of tissue or body fluid cultures.  Additionally, there is a cryptococcal antigen test which can rapidly determine if tested blood and/or cerebrospinal fluid is infected.  Although c. gattii is slow to respond to treatments, it has responded favorably to the use of anti-fungal and antibiotic drugs.

C. gattii is quickly becoming an epidemic in the Northwest United States.  Although efforts to study and understand the disease's emergence in British Columbia have generated valuable data, there are many questions which remain unanswered.  Currently, the CDC in Atlanta, GA, is working with multiple state public health departments to facilitate clinical surveillance of the progression of c. gattii.  But additional national and international efforts must be organized!  One of the most important steps to controlling an outbreak of c. gattii is recognizing it as an emerging fungal infection in the United States and declaring it a priority pathogen in the eyes of America's funding agencies.


References:

Dell'Amore, C. (2010). New, Deadly Cryptococcus Gattii Fungus Found in U.S. National Geographic News. Retrieved from http://news.nationalgeographic.com/news/2010/04/100421-new-fungus-cryptococcus-gattiii-deadly-health-science/

Dixit, A., Carroll, S., & Qureshi, S. (2009). Cryptococcus gattii: An Emerging Cause of Fungal Disease in North America. Interdisciplinary Perspectives on Infectious Diseases, 1-13. doi:10.1155/2009/840452.

Doheny, K. (2010). Airborne Fungus Expected to Spread in U.S.. WebMD. Retrieved from http://www.webmd.com/lung/news/20100423/airborne-fungus-expected-to-spread-in-u-s

Galanis, E., & MacDougall, L. (2010). Epidemiology of Cryptococcus gattii, British Columbia, Canada, 1999-2007. Emerging Infectious Diseases, 16(2), 251-257. doi:10.3201/eid1601.090900.

Harris, J., PhD. (2010). Mystery Disease X. Centers for Disease Control and Prevention. Retrieved from http://www.doh.wa.gov/ehp/ts/Zoo/workshop/crypto-harris.pdf

MacDougall, L., Kidd, S., Galanis, E., Mak, S., Leslie, M., Cieslak, P., et al. (2007). Spread of Cryptococcus gattii in British Columbia, Canada, and Detection in the Pacific Northwest, USA. Emerging Infectious Diseases, 13(1), 42-50. Retrieved from Academic Search Complete database.

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