My name is Ayat Aljubran, I am a grad student at Western Illinois University in the Department of Biology Sciences.

                                 From the Tree to your Body

General description:

    

          Cryptococcus gatti  belongs to the Basidiomycota phylum. This fungus is usually found in tropical and subtropical areas.  It was first recognized  in Vancouver Island 1999 after several cases of  pneumonia were reported in people and animals. The fungus was detected in 1970 in one patient in Seattle. The outbreak  continue to many areas  around Vancouver, Canada.

        

          C.gatti is an opportunistic pathogenic fungus which means it can infect people under certain conditions, including immunocompromised patients, such as AIDS patients and transplant organ patients.  Cryptococcosis can be caused by two different species C.gattii and C.neoformans in humans and animals. The primary infection occurs by breathing the spores into the lungs causing pulmonary infections.  The infection also can spread through the blood reaching other organs in the body such as the brain (central nervous system inflammatory) resulting in death. In addition, the fungus causes severe infection that may cause blindness. 

          The fungus is dimorphic  which mean can switched from  a yeast and a hyphal stage. C.gatti has four different molecular types VGI, VGII, VGIII, and VGIV. 

Figure 1. Bird seed agar plate showing brown colonies of C. gattii and white colonies of Candida albicans

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Microscopic and Macroscopic features:

          The macroscopic colonies are dark brown , under the microscopic the fungus

shows circular yeast cells surround by a thick capsule of polysaccharides. This yeast have melanin that provide high resistant against environment stress and help the fungus evade the immune responses from the host cells.

                                                                                                              

Figure 2. C. gattii fungus has been found in soil and plants.

Distribution:

          Based on human clinical samples,  C.gattii has been found in temperate, tropical and subtropical areas including, Canada, Africa, Europe, Australia, the United States, Argentina, Austria, Canada, China, Congo, India, Italy, Japan, South Korea, the Netherlands, Spain, among others (2).

The fungus has been  isolated from  animals including koala, ferret, tapir, cheetah, and llama.

Figure 3.  Sistribution for C.gattii around the world.    

Habitat:

           C.gattii was first isolated from Australia.  The fungus is commonly isolated from tree surfaces, leaves, soil, and water. No seasonally has been observed (4).

The Outbreak in Canada:

    

           In 1999 British Columbia, Canada, had the highest numbers of C.gattii infections (1). Around 715,000 people was reported with infections (average 5.8 per million) (8)(9). The infection occur by inhaling spores. The primery site of infection is the lungs and the infection can be transported to other organs in  the body. (8)

          During 1999 to 2007 different cases appeared with different symptoms including pulmonary, chest pain, and cough, and  central nervous system infections, meningoencephalitis or brain cryptococcomas (8)(9). Some severe infections  occur in immunocompromised individuals such as HIV/ diabetes patients and people with invasive cancer (9). A total 6.2% of the confirmed cases by C.gattii  had HIV in British Colombia (8),  76.6% had lung cryptococcoma (8), 75.4% of the people did not have HIV/AIDS (8) and 8.7% (19 people) who died were elderly with central nervous system infections (8).

Clinical cases:

          Cryptococcus sp is responsible of 1 million infections every year. At least 176 cases were reported between 1999-2006 in British Columbia, 3 of them died.

Many cases include severepulmonary and central nervous system infections.

Case 1:

Female 77 years old in Vancouver Island, the symptoms were chronic dry cough, shortness of breath, headache, and chest pain. Entire tests were conducted to help  with diagnosis, including blood count, urinalysis, and liver function tests. The diagnosis was C. gattii VGIIa (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2690522/)

Case 2:

A male 39 years old, showed several symptoms including headache, low degree fever, cough. He was  for several weeks in Vancouver 7 months before the symptoms start showing.

The diagnosis was C. gattii VGIIa strains (www.ncbi.nlm.nih.gov/pmc/articles/PMC2690522).

Figure 3. Images from patients with C. gattii causing pulmonary and central nervous system.

  Diagnosis:

·      Microscopy:

• Because C. gattii encodes for a  capsule around the fungus,   India Ink  is more effective for diagnosis of this fungus because it does not stain the capsule. Calcofluor white fluorescent stain  is also sensitive for the detection.
• Radiographs are useful for diagnosis the pulmonary infection.
• MRI scan for brain infection.
•  Serological tests from blood, and cerebrospinal fluid(6).

Treatment:

          For C. gattii infection fluconazole is useful and there is no significant resistance reported , the resistance usually appears after along time of treatment (7). For severe infections Amphotericin B is uses for at least 6 months (7).

 References:

1-Springer, D. J., Phadke, S., Billmyre, R. B., & Heitman, J. (2012). Cryptococcus gattii, No Longer an Accidental Pathogen? Current Fungal Infection Reports Curr Fungal Infect Rep, 6(4), 245-256. doi:10.1007/s12281-012-0111-0

2-Springer, D. J., & Chaturvedi, V. (2010). Projecting Global Occurrence of Cryptococcus gattii [Abstract]. Emerg. Infect. Dis. Emerging Infectious Diseases, 16(1), 14-20. doi:10.3201/eid1601.090369

3- Galanis, E., Hoang, L., Kibsey, P., Morshed, M., & Phillips, P. (2009). Clinical Presentation, Diagnosis and Management of Cryptococcus gattii Cases: Lessons Learned from British Columbia. Canadian Journal of Infectious Diseases and Medical Microbiology, 20(1), 23-28. doi:10.1155/2009/719659

4- Kidd, S. E., Chow, Y., Mak, S., Bach, P. J., Chen, H., Hingston, A. O., . . . Bartlett, K. H. (2006). Characterization of Environmental Sources of the Human and Animal Pathogen Cryptococcus gattii in British Columbia, Canada, and the Pacific Northwest of the United States. Applied and Environmental Microbiology, 73(5), 1433-1443. doi:10.1128/aem.01330-06

5-Morera, N., Juan-Sallés, C., Torres, J. M., Andreu, M., Sánchez, M., Zamora, M. Á, & Colom, M. F. (2011). Cryptococcus gattii infection in a Spanish pet ferret ( Mustela putorius furo ) and asymptomatic carriage in ferrets and humans from its environment. Med Mycol Medical Mycology, 1-6.

doi:10.3109/13693786.2011.564216

6-Liaw, S., Wu, H., & Hsueh, P. (2010). Microbiological characteristics of clinical isolates of Cryptococcus neoformans in Taiwan: Serotypes, mating types, molecular types, virulence factors, and antifungal susceptibility. Clinical Microbiology and Infection, 16(6), 696-703. doi:10.1111/j.1469-0691.2009.02930.x

7- Rossi, S. A., Trevijano-Contador, N., Scorzoni, L., Mesa-Arango, A. C., Oliveira, H. C., Werther, K., . . . Fusco-Almeida, A. M. (2016). Impact of Resistance to Fluconazole on Virulence and Morphological Aspects of Cryptococcus neoformans and Cryptococcus gattii Isolates. Front. Microbiol. Frontiers in Microbiology, 7.

 doi:10.3389/fmicb.2016.00153

8-Galanis, E., Macdougall, L., Kidd, S., & Morshed, M. (2010). Epidemiology of Cryptococcus gattii , British Columbia, Canada, 1999–2007. Emerg. Infect. Dis. Emerging Infectious Diseases, 16(2), 251-257. doi:10.3201/eid1602.090900

9- Cryptococcus gattii Infections on Vancouver Island, British Columbia, Canada: Emergence of a Tropical Fungus in a Temperate Environment

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