Spread of Cryptococcus gattii in British Columbia, Canada, and detection in the Pacific Northwest, USA.Cryptococcus gattii Cryptococcus gattii, also known as Cryptococcus neoformans var gattii, is a yeast-like fungus found in tropical and subtropical climates. If a human or animal breathes in spores or cells, it causes a lung infection called cryptococcosis which can be fatal , emergent on Vancouver Island Vancouver Island (1991 pop. 579,921), 12,408 sq mi (32,137 sq km), SW British Columbia, Canada, in the Pacific Ocean; largest island off W North America. It is c.285 mi (460 km) long and c. , British Columbia British Columbia, province (2001 pop. 3,907,738), 366,255 sq mi (948,600 sq km), including 6,976 sq mi (18,068 sq km) of water surface, W Canada. Geography
(BC), Canada, in 1999, was detected during 2003-2005 in 3 persons and 8 animals that did not travel to Vancouver Island during the incubation period incubation period
1. See latent period.
2. See incubative stage.
Incubation period ; positive environmental samples were detected in areas outside Vancouver Island. All clinical and environmental isolates found in BC were genotypically consistent with Vancouver Island strains. In addition, local acquisition was detected in 3 cats in Washington and 2 persons in Oregon. The molecular profiles of Oregon isolates differed from those found in BC and Washington. Although some micro-climates of the Pacific Northwest are similar to those on Vancouver Island, C. gattii concentrations in off-island environments were typically lower, and human cases without Vancouver Island contact have not continued to occur. This suggests that C. gattii may not be permanently colonized Colonized
This occurs when a microorganism is found on or in a person without causing a disease.
Mentioned in: Isolation in off-island locations.
In 1999, Cryptococcus gattii emerged on Vancouver Island, British Columbia (BC), Canada, among residents, visitors to the island, and domestic and wild animal populations. Disease incidence on Vancouver Island plateaued at 36 cases/million population/year during 2002-2005, markedly higher than rates reported in other C. gattii--endemic areas (1,2).
Unlike the closely related species C. neoformans, a common opportunistic pathogen of immunocompromised hosts, C. gattii affects primarily immunocompetent im·mu·no·com·pe·tent
Having the normal bodily capacity to develop an immune response following exposure to an antigen.
im persons. Two C. gattii serotypes, B and C, have been described (3). The fungus is acquired through inhalation of airborne propagules and may cause pulmonary and central nervous system disease. Activities that disturb colonized soil or trees may increase the likelihood of exposure (4). Disease acquisition likely also depends on host factors, including underlying lung conditions and oral steroid use (M. Fyfe, unpub, data).
In a study of Vancouver Island human C. gattii serotype serotype /se·ro·type/ (ser´o-tip) the type of a microorganism determined by its constituent antigens; a taxonomic subdivision based thereon.
v. B cases from January 1999 through December 2001, infection was most common in men and those >60 years of age. Chest radiograph radiograph /ra·dio·graph/ (-graf?) the film produced by radiography.
n. showed single or multiple pulmonary nodules Nodules
A small mass of tissue in the form of a protuberance or a knot that is solid and can be detected by touch.
Mentioned in: Leprosy in 68% of patients. Symptoms included severe cough and shortness of breath Shortness of Breath Definition
Shortness of breath, or dyspnea, is a feeling of difficult or labored breathing that is out of proportion to the patient's level of physical activity. , often accompanied by chills, night sweats, and anorexia. Approximately 20% of patients had cryptococcal meningitis cryptococcal meningitis Neurology An opportunistic infection of the meninges and spinal cord by Cryptococcus neoformans At-risk Pts AIDS, lymphoma, DM Clinical Severe headache, confusion, photosensitivity, blurred vision, fever, speech difficulties (M. Fyfe, unpub, data). The median incubation period was [approximately equal] 6-7 months (5).
C. gattii has been isolated from more than 10 different native tree species on Vancouver Island and from the surrounding soil and air (6, 7; S.E. Kidd et al., in press). Despite sampling in areas both on and off the island, positive environmental isolates have, until recently, been confined to the Coastal Douglas Fir Douglas fir: see pine.
Any of about six species of coniferous evergreen timber trees (see conifer) that make up the genus Pseudotsuga, in the pine family, native to western North America and eastern Asia. and very dry Coastal Western Hemlock hemlock, any tree of the genus Tsuga, coniferous evergreens of the family Pinaceae (pine family) native to North America and Asia. The common hemlock of E North America is T. biogeoclimatic zones along the east coast of Vancouver Island (8, Figure 1).
[FIGURE 1 OMITTED]
VGIIa and VGIIb are the most commonly identified genotypes among human, animal, and environmental isolates from Vancouver Island (6). The VGI VGI Virtual Graphics Interface
VGI Valley Girl Intelligentsia (Julie Ruin song)
VGI Vertical Gyro Indicator
VGI Vegetation Index genotype has been isolated less frequently from clinical and environmental samples (6,9; S.E. Kidd et al., in press).
The emergence of C. gattii infection on Vancouver Island, a temperate climate, was unusual because this
species previously was associated only with tropical and subtropical sub·trop·i·cal
Of, relating to, or being the geographic areas adjacent to the Tropics.
of the region lying between the tropics and temperate lands
climates (10,11). To facilitate surveillance activities, cryptococcal disease was made provincially notifiable notifiable /no·ti·fi·a·ble/ (no?ti-fi´ah-b'l) necessary to be reported to a government health agency.
necessary to be reported to the relevant government authority. Said of individual diseases. in BC in 2003, formalizing laboratory reporting originally developed in response to disease emergence. A primary goal of surveillance was to monitor fungal spread to other areas of BC.
Vancouver Island is the largest island on the Pacific Coast of North America North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. , covering 32,000 [km.sup.2], with a population of [approximately equal to] 700,000. It is separated from the BC mainland by the Strait of Georgia Noun 1. Strait of Georgia - the strait separating Vancouver Island from the Canadian mainland , a body of water [approximately equal to] 50 km wide that contains several smaller islands known as the Gulf Islands (Figure 1). Travel among Vancouver Island, the BC mainland, and the Gulf Islands is very common, with an estimated 17.3 million passengers transported on BC Ferries' Vancouver Island routes annually (12).
Until 2004, all human cases of C. gattii infection reported to the British Columbia Centre for Disease Control were among those living on or traveling to Vancouver Island during the year before symptoms appeared. In December 2004, the first evidence of disease in humans without exposure to Vancouver Island or other known C. gattii--endemic areas was detected. This article summarizes the epidemiologic and environmental support for disease acquisition in parts of the BC lower mainland The Lower Mainland is the name that residents of British Columbia apply to the region surrounding the City of Vancouver. According to the 2001 census, over 2.2 million people live in the region; sixteen of the province's thirty most populous municipalities are located there and focal areas of the US Pacific Northwest.
We interviewed persons from whom C. gattii serotype B was cultured through December 31, 2005, and who did not report contact with Vancouver Island or other known disease-endemic areas. We conducted telephone interviews by using a standard questionnaire to assess demographic information, travel history, risk factors for infection, underlying medical conditions See carpal tunnel syndrome, computer vision syndrome, dry eyes and deep vein thrombosis. , and clinical symptoms. Risk factors and travel exposures were assessed for the 1-year period before the onset of illness (or before diagnosis, in asymptomatic cases). Health authorities in neighboring provinces (Canada) and states (USA), where the disease is not reportable, were provided with case investigation forms and encouraged to investigate cryptococcal disease in immunocompetent persons.
Reports of animal cases were informally collected through veterinary networks in BC. Cases from the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. were reported by state veterinary epidemiologists. Infection in the animals was diagnosed histologically or identified as C. gattii serotype B by culture. None of the animals had traveled to Vancouver Island or other disease-endemic areas.
From October 2001 through December 2005, environmental sampling was undertaken in the BC mainland, the BC Gulf Islands, and the US Pacific Northwest. We sampled 22 map grids as defined by the l:50,000-scale National Topographic System The National Topographic System or NTS (French: Système national de référence cartographique) is the topographic system used by Canada for providing general purpose maps of the country. NTS maps are available in 1/50,000 and 1/250,000 scales. of Canada (NTS NTS National Technical Systems
NTS National Trust for Scotland
NTS Nevada Test Site
NTS NT Server (Microsoft Windows)
nts Not the Same
NTS National Traffic System (amateur radio) ) and US Geological Survey The term geological survey can be used to describe both the conduct of a survey for geological purposes and an institution holding geological information.
A geological survey (USGS USGS United States Geological Survey (US Department of the Interior) ) mapping system. Geographic data Geographic data is about much more than electronic pictures of maps.
The geographic data that describes our world allows for city planning, flood prediction and relief, emergency service routing, environmental assessments, wind pattern monitoring and many other applications. were assembled as described elsewhere (S.E. Kidd et al., in press). Purposive pur·po·sive
1. Having or serving a purpose.
2. Purposeful: purposive behavior.
pur sampling was conducted at selected sites and areas surrounding the homes of persons with C. gattii infection, those who reported travel to Vancouver Island and those who did not. Sampled environments included front and back yards, walking trails, public parks, and recreational areas. Trees, small woody debris, soil, air, and water were sampled as described elsewhere (S.E. Kidd et al., in press).
Sample positivity was scored binarily. C. gattii concentration was expressed as CFU/gram, CFU/[m.sup.3], and CFU/ 100 mL in soil, air, and water, respectively. The concentrations of multiple samples were described by the geometric mean (mathematics) geometric mean - The Nth root of the product of N numbers.
If each number in a list of numbers was replaced with their geometric mean, then multiplying them all together would still give the same result. and geometric standard deviation In probability theory and statistics, the geometric standard deviation describes how spread out are a set of numbers whose preferred average is the geometric mean. If the geometric mean of a set of numbers is denoted as μg . When more than 1 sample was taken from a single sampling point (e.g., the same tree), only the first sample was included.
Identification and Genetic Characterization
We initially cultured the samples on Staib media (13). Resulting dark brown colonies were grown on canavanine-glycine-bromothymol blue (CGB CGB Certified Graduate Builder (professional builder designation)
CGB Consumer and Governmental Affairs Bureau
CGB Commonwealth Geographical Bureau (UK)
CGB Game Boy Color ) agar (14) to differentiate C. gattii from C. neoformans and then serotyped (Crypto-check, Iatron Laboratories, Tokyo, Japan).
Molecular types were identified by a previously described PCR-based restriction fragment length polymorphism restriction fragment length polymorphism
n. Abbr. RFLP
Intraspecies variations in the length of DNA fragments generated by the action of restriction enzymes and caused by mutations that alter the sites at which these enzymes act, changing (RFLP RFLP
restriction fragment length polymorphism
restriction fragment length polymorphism.
RFLP ) method (15), which was adapted for further discrimination of variation within the VGII molecular type (9). The URA Ura
uracil. 5 gene was amplified as previously described (15) and then completely digested at 37[degrees]C in a 20-[micro]L reaction containing 1x NEB2 buffer, 1x bovine serum albumin serum albumin
See seralbumin. , and 4 U each of Hha I, Dde I, and BsrG I (New England Biolabs New England Biolabs (NEB) produces and supplies reagents for the life science industry. NEB offers a large selection of recombinant and native enzymes for genomic research. It also offers products in the areas related to proteomics and drug discovery. , Inc., Ipswich, MA, USA). RFLP products were subjected to electrophoresis and visualized on a 3% agarose agarose
more highly purified form of agar with similar uses to agar and widely used in the separation of nucleic acid fragments. gel prestained with ethidium bromide Ethidium bromide (sometimes abbreviated as EtBr) is an intercalating agent commonly used as a nucleic acid stain in molecular biology laboratories for techniques such as agarose gel electrophoresis. . Control strains were used for each possible C. gattii RFLP pattern: WM179 (VGI), NIH "Not invented here." See digispeak.
NIH - The United States National Institutes of Health. 444 (VGIIa), RB28 (VGIIb), WM161 (VGIII), and WM779 (VGIV). C. neoformans strains WM148 (VNI VNI Visual Numerics Inc
VNI Valeur Nette d'Inventaire (French)
VNI Village Networks Inc.
VNI Virtual Network Interface
VNI Viet Nam international
VNI Visual Numerics Inc. ), WM626 (VNII), WM628 (VNIII), and WM629 (VNIV VNIV Vereniging Nederlandse Incontinentie Verpleegkundigen (Dutch Association of Incontinence Nurses) ) were also included.
Multilocus sequence typing Multilocus sequence typing (MLST) is a technique in molecular biology for the typing of multiple loci. The procedure characterizes isolates of bacterial species using the DNA sequences of internal fragments of multiple (usually seven) housekeeping genes. was performed for selected isolates by using methods previously described (8) with the use of 2 additional loci loci
[L.] plural of locus.
loci Plural of locus, see there , PLB (Picture Level Benchmark) A benchmark for measuring graphics performance on workstations. The Benchmark Interface Format (BIF) defines the format, the Benchmark Timing Methodology (BTM) performs the test, and the Benchmark Reporting Format (BRF) generates results in 1 and IGS IGS - Internet Go Server. (16). We isolated total DNA DNA: see nucleic acid.
or deoxyribonucleic acid
One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. from histopathology his·to·pa·thol·o·gy
The science concerned with the cytologic and histologic structure of abnormal or diseased tissue.
The study of diseased tissues at a minute (microscopic) level. specimens (n = 3) by using the DNeasy Tissue kit (QIAGEN Inc., Mississauga, Ontario For the First Nation, see .
Mississauga (pronounced: [ˌmɪsɪˈsɑgə] , Canada). Cryptococcal-specific PCR-RFLP PCR-RFLP Polymerase Chain Reaction–Restriction Fragment Length Polymorphism was conducted as described above. The internal transcribed spacer ITS (for internal transcribed spacer) refers to a piece of non-functional RNA situated between structural ribosomal RNAs (rRNA) on a common precursor transcript. Read from 5' to 3', this polycistronic rRNA precursor transcript contains the 5' external transcribed sequence (5' ETS), region (ITS1-5.8S-ITS2) was amplified and sequenced for identification of C. gattii--specific polymorphisms (17).
Epidemiology of Human Infection
Five persons with culture-confirmed C. gattii, 3 in BC and 2 in Oregon, did not report exposure to Vancouver Island or other cryptococcal disease--endemic areas (Figure 2). Case-patients 1 through 4 received a diagnosis or reported symptom onset from September through December 2004. Case-patient 5, who had a fatal infection, received a diagnosis in December 2005.
[FIGURE 2 OMITTED]
Case-patient 1 was a 47-year-old man living in BC who was hospitalized with cough, chills, night sweats, nausea, loss of appetite loss of appetite Medtalk Anorexia, see there , muscle pain, headache, and neck stiffness. Both lung and brain cryptococcomas were identified. He had chronic hepatitis Chronic hepatitis
Long lasting inflammation of the liver due to viruses or other causes.
Mentioned in: Tube Compression of the Esophagus and Stomach
chronic hepatitis C infection and a history of drug addiction drug addiction
or chemical dependency
Physical and/or psychological dependency on a psychoactive (mind-altering) substance (e.g., alcohol, narcotics, nicotine), defined as continued use despite knowing that the substance causes harm. . At the time of infection, he smoked 20-40 cigarettes/day. His residence, a farmhouse undergoing significant renovations, was located in NTS grid 092G/05 on the coast north of Vancouver. Environmental exposures included yard and landscaping work at this property.
Case-patient 2 was a 48-year-old woman living in BC who experienced shortness of breath, fever, chills, headache, night sweats, loss of appetite, nausea, and muscle pain. A lung mass was identified by computed tomography Computed tomography (CT scan)
X rays are aimed at slices of the body (by rotating equipment) and results are assembled with a computer to give a three-dimensional picture of a structure. . She had no known underlying health conditions. She resided on the BC lower mainland within NTS grid 092G/02; her last visit to Vancouver Island was 4 years before the onset of her illness. In the year before onset, considerable deforestation deforestation
Process of clearing forests. Rates of deforestation are particularly high in the tropics, where the poor quality of the soil has led to the practice of routine clear-cutting to make new soil available for agricultural use. had occurred near her residence to clear land for housing developments. During this period, she also traveled [approximately equal to] 1 day/week to garden centers and nurseries within NTS 092G/02 to obtain shrubs, trees, and new topsoil for yard landscaping she carried out at her residence.
Case-patient 3 was a 73-year-old woman living in BC who had chronic renal failure chronic renal failure Chronic kidney failure Nephrology A slow decline in renal function, which may be 2º to chronic HTN, DM, CHF, SLE, or sickle cell anemia and, if extreme, leads to ESRD, mandating kidney dialysis; an abrupt decline in renal function may be requiring dialysis and a history of lung disease lung disease Pulmonary disease Pulmonology Any condition causing or indicating impaired lung function Types of LD Obstructive lung disease–↓ in air flow caused by a narrowing or blockage of airways–eg, asthma, emphysema, chronic bronchitis; and breast cancer. She was asymptomatic; a cryptococcal lung nodule nodule: see concretion.
In geology, a rounded mineral concretion that is distinct from, and may be separated from, the formation in which it occurs. was identified radiographically after she had hip surgery in December 2004. No nodule was apparent on imaging conducted <2 months earlier, which suggests recent acquisition. The patient resided in NTS grid 092G/07. She last visited Vancouver Island 14 years before her diagnosis. She had reduced mobility and consequently little outdoor exposure.
Case-patient 4 was a 59-year-old man living in Oregon who began to experience cough, shortness of breath, fever, chills, weight loss, nausea, and muscle pain in December 2004. He had undergone a kidney transplant kidney transplant
or renal transplant
Replacement of a diseased or damaged kidney with one from a living relative or a legally dead donor. The former's tissue type is more likely to match, reducing the chance of rejection; but removal puts the donor at risk, in September 2003 and reported scarring of lung tissue due to his occupation. His place of residence was located within USGS grid 44123-A1B4. He had not traveled outside Oregon in the year before symptom onset.
Case-patient 5 was an 87-year-old man living in Oregon (USGS grid 45122-C5D8). He was hospitalized in December 2005 with meningitis, accompanied by fever, weight loss, and loss of appetite. His medical history included chronic lymphocytic leukemia chronic lymphocytic leukemia
n. Abbr. CLL
Lymphocytic leukemia occurring mainly in older adults, characterized by slow onset and gradual progression of symptoms. , and he had taken oral steroids in the year before diagnosis. He had traveled to parts of Oregon, Washington, and Colorado during his exposure period.
Epidemiology of Off-island Animal Cases
In BC, a retrospective review retrospective review,
a posttreatment assessment of services on a case-by-case or aggregate basis after the services have been performed. of companion animal cases identified 8 culture-confirmed serotype B cases, which occurred in a ferret, a llama llama (lä`mə), South American domesticated ruminant mammal, Lama glama, of the camel family. Genetic studies indicate that it is descended from the guanaco. , and 6 cats. Specimens were collected from December 2003 through December 31, 2005; animal residences were located throughout the BC lower mainland (Figure 2).
In Washington, 3 cats with cryptococcal disease residing in USGS 48122-G1H4, close to the BC-USA border, were reported from February through June 2005 (Figure 2). All cases were diagnosed by histopathologic examination, and no cultures were obtained.
From October 2001 through December 2005, 3% of 2,033 off-island environmental samples were positive for C. gattii (Table 1). Swab samples included 45% of samples from trees and other structures (n = 925), 38% from soil (n = 781), 15% from air (n = 304), and 1% from water (n = 23).
Five positive air samples were recovered from 2 focal areas of the lower mainland at 2 different times (Figure 3). The first 2 were collected from air in NTS grid 092G/02 on the same day in October 2002. No other positive samples were detected in 2003 despite further sampling at this site and others. In July 2004, a third positive air sample was collected from grid 092G/02 and 2 more from grid 092G/01. Despite extensive sampling in these areas and other parts of the BC lower mainland (n = 1,140), C. gattii was not isolated from colonized sources such as trees or soil.
[FIGURE 3 OMITTED]
Among environmental samples taken outside Vancouver Island, C. gattii was most often recovered from the Gulf Islands (Table 1). NTS grid 092B/14 had the highest proportion of positive samples (52/220; 24%). Colonized sources were identified from a single Gulf Island within this grid in March, May, and June of 2004. In 2005, positive soil and tree samples were obtained in February, August, September, and October from 3 of the Gulf Islands (NTS grids 092B/14 and 092F/01) and Washington (USGS grid 48122-G1H4). From among 50 samples collected a month apart in Washington within 10 km of the BC border (USGS grid 48122-G1H4), a single soil sample and a swab of a fence post were positive. An additional 27 samples from other sites along the US side of the border (USGS grids 48122-G1H4 and 48122-G5H8) were negative, as were all 197 samples collected from several areas of Oregon (USGS grids 44123-A1B4 and 45122-C5D8). The geometric mean concentration of detected C. gattii among soil and air samples taken from various sites outside Vancouver Island is summarized in Table 2.
Molecular Typing Results for Human, Animal, and Environmental Isolates
Table 3 and Figure 4 summarize the molecular subtyping results for human and animal isolates from persons and animals with no recent exposure to Vancouver Island, as well as environmental isolates obtained from off-island locations.
[FIGURE 4 OMITTED]
Of the 5 human cases, 3 were attributed to the VGIIa molecular type, 1 to the VGIIb molecular type, and 1 to the VGI molecular type. However, although all 3 molecular types have been identified among clinical and environmental isolates from Vancouver Island, multilocus sequence typing (MLST MLST Multi Locus Sequence Typing
MLST Medical Logistics Support Team
MLST Mini Losi Super Truck (1/18th scale radio control vehicle) ) results indicated that both the VGIIa and VGIIb strains from Oregon cases were genetically distinct from previously characterized Vancouver Island isolates (9,16). The Oregon case 4 VGIIa isolate differed from Vancouver Island VGIIa at 1 locus, while Oregon case 5 VGIIb differed from Vancouver Island isolates at 4-5 loci, where it was more similar to Vancouver Island VGIIa than VGIIb (Table 4).
Cryptococcai DNA isolated from the formalin-fixed, paraffin-embedded tissue of 3 cats in Washington belonged to the VGIIa molecular type. MLST profiles could not be determined in these cases because of the relatively poor quality and yield of DNA from the fixed tissue.
Most off-island environmental isolates that were typed belonged to the VGIIa molecular type. These included 4 of the 5 isolates from lower mainland air samples (the fifth could not be separated from contaminants) and 90% of 20 typed isolates from the NTS grid with the highest proportion of positive off-island environmental samples (092B/14). All tested environmental VGIIa isolates from BC and Washington possessed identical MLST profiles to those of representative isolates from Vancouver Island (Table 3).
Surveillance for C. gattii, conducted in BC since the pathogen emerged on Vancouver Island, identified its spread to off-island locations in 2005. To date, 3 humans and 8 animals residing within the BC lower mainland who had not traveled to Vancouver Island or other known cryptococcal disease--endemic areas within the incubation period for disease have been found to have culture-confirmed C. gattii infection. All but 1 case belonged to the VGIIa subtype (programming) subtype - If S is a subtype of T then an expression of type S may be used anywhere that one of type T can and an implicit type conversion will be applied to convert it to type T. , the dominant genotype among clinical and environmental isolates from Vancouver Island (6,9,16). Human surveillance findings are supported by a parallel spread of C. gattii to animal populations on the BC mainland and positive air samples in this area. In addition, C. gattii infections with no recent link to Vancouver Island or other disease-endemic areas have been reported in 3 cats in Washington and 2 persons in Oregon. These cases represent the first evidence of local disease acquisition in this part of the United States. One historic case of VGIIa C. gattii (NIH444) was diagnosed in Seattle in the early 1970s; however, residence and travel history for the infected person are unknown (6,9,16).
Before the identification of new disease-endemic areas, all humans with C. gattii infection either lived within or traveled to the Coastal Douglas Fir and very dry Coastal Western Hemlock biogeoclimatic zones (Figure 1), located along the eastern edge of Vancouver Island. These zones are characterized by warm, dry summers and mild, wet winters and extend into the southern Gulf Islands and the BC lower mainland. Climates with comparable rainfall and temperature extend south into parts of Washington and Oregon in the United States (18). Franklin and Dyrness (19) identified plant communities similar to those in BC in the San Juan Islands San Juan Islands (săn wän), archipelago of 172 islands constituting San Juan co., NW Wash., E of Vancouver Island. The islands were visited and named c.1790 by Spanish explorers. and Puget Trough of Washington and the Willamette Valley The Willamette Valley (pronounced [wɪˈlæ.mɪt], with the accent on the second syllable) is the region in northwest Oregon in the United States that surrounds the Willamette River as it proceeds northward from its in Oregon. These ecologic likenesses to BC support the idea that C. gattii may colonize col·o·nize
v. col·o·nized, col·o·niz·ing, col·o·niz·es
1. To form or establish a colony or colonies in.
2. To migrate to and settle in; occupy as a colony.
3. niche areas of the US Pacific Northwest.
Although microclimate microclimate
Climatic condition in a relatively small area, within a few feet above and below the Earth's surface and within canopies of vegetation. Microclimates are affected by such factors as temperature, humidity, wind and turbulence, dew, frost, heat balance, similarities exist, we could not determine whether the isolation of C. gattii from areas outside Vancouver Island represents true colonization or transient dispersal of the organism at the time of sampling, such as through wind flow or mechanical vectors/fomites. Despite repeated sampling, no environmental source (e.g., tree, soil) of the VGIIa isolates detected in air on the BC mainland has been found. Either an undiscovered reservoir exists on the BC mainland or detectable airborne C. gattii was aerosolized Adj. 1. aerosolized - in the form of ultramicroscopic solid or liquid particles dispersed or suspended in air or gas
gaseous - existing as or having characteristics of a gas; "steam is water is the gaseous state" and dispersed from known colonized sources, such as Vancouver Island or the Gulf Islands. Washington VGIIa environmental isolates, identical by MLST to those from BC, may represent recent dispersal from BC or independent foci of colonization.
Sampling sites on Vancouver Island have shown different patterns of C. gattii colonization over time (4). Transiently positive sites are characterized by a positive C. gattii isolation, followed by a series of negative samples over a period of months or years. Permanently colonized sites consistently yield positive samples. Intermittently colonized sites yield cycles of positive and negative samples over time, perhaps the result of population fluctuation above and below the limits of detection as the organism competes with local microbiota Microbiota (human)
Microbial flora harbored by normal, healthy individuals. A number of microorganisms have become adapted to a particular site or ecologic niche in or on their host. , while it adjusts to a new ecologic niche. Repeated sampling of non--Vancouver Island sites previously positive for C. gattii may show the extent of colonization and the likelihood of these areas becoming C. gattii--endemic.
The detected concentration of C. gattii in air and soil samples from the BC lower mainland and northern Washington was lower than in samples from Vancouver Island. Based on a comparison of geometric means, the detected C. gattii concentration in air samples from the mainland was 4-fold lower than in Vancouver Island air Vancouver Island Air is a Vancouver Island seaplane company serving coastal British Columbia, based in Campbell River. History
The airline has been in operation since 1985, offering charter and scheduled service with single and multi-engine aircraft on floats from samples collected at the same time of the year (Table 2). C. gattii concentration in soil from northern Washington and 2 of the Gulf Islands was [approximately equal to] 5x lower than in soil from Vancouver Island. Only in a limited area of 1 particular Gulf Island in grid 092B/14 was C. gattii concentration in soil higher (3.3-fold) than in soil from Vancouver Island.
While direct comparisons with infected persons living on or traveling to Vancouver Island are not possible because of the small number of off-island cases, humans affected by C. gattii in off-island environments may have a higher rate of serious underlying health conditions. Among cases in BC and Oregon, persons were affected by renal failure renal failure
Acute or chronic malfunction of the kidneys resulting from any of a number of causes, including infection, trauma, toxins, hemodynamic abnormalities, and autoimmune disease, and often resulting in systemic symptoms, especially edema, , chronic hepatitis C infection, and cancer (i.e., chronic lymphocytic leukemia, breast cancer). In an age-matched case-control study case-control study,
n an investigation employing an epidemiologic approach in which previously existing incidents of a medical condition are used in lieu of gathering new information from a randomized population. , persons from Vancouver Island with C. gattii infection were not significantly more likely than noninfected island residents to have had cancer (M. Fyfe, unpub, data) or liver disease Liver Disease Definition
Liver disease is a general term for any damage that reduces the functioning of the liver.
The liver is a large, solid organ located in the upper right-hand side of the abdomen. (L. MacDougall, unpub. data). Persons with compromised immune systems may be more susceptible to infection with C. gattii at the lower concentrations observed in most off-island environments.
Even with ongoing surveillance in BC, the last reported case of symptom onset in a person with C. gattii infection who had not traveled to Vancouver Island was in December 2004. As of May 2006, no further cases had been detected, a finding at odds with the notion of permanent colonization. The onset of infections in the lower mainland of BC (September-December 2004) coincides with positive air samples on the mainland some months earlier (July 2004), given known variations in individual incubation periods (Figure 3) (5). Although animal cases did continue to occur during 2005-2006, environmental sampling attempts throughout 2005 did not detect the organism in the lower mainland. This result indicates either that permanent colonization did not occur in the sampled areas or that C. gattii was present below the limits of detection.
As on Vancouver Island, C. gattii in off-island areas was first detected in companion animals. Animal cases began to be regularly identified in March 2004, [approximately equal to] 6 months before human illness was reported in this area. As on Vancouver Island and in Australia, cats were affected more often than other companion animals (20,21). However, illness occurred in a ferret and llama, rare animals also infected early in the emergence on Vancouver Island, which may suggest that these species are particularly sensitive to infection. Despite substantial underreporting of animal cases, data from Vancouver Island suggest that animal cases exceeded human cases by almost 75%, highlighting their value as a sentinel indicator of disease (20).
Clinical and environmental isolates from the BC mainland, Gulf Islands, and northern Washington tested by MLST were identical to representative isolates from Vancouver Island at the 6 loci investigated (Table 4) (9,16). However, although isolates from the C. gattii human case-patients living in Oregon were typed as VGIIa and VGIIb, MLST analyses indicated that these isolates were genetically distinct from BC and Washington clinical and environmental isolates. A BLAST comparison (www.ncbi.nlm.gov/BLAST) to sequences from previous studies and those represented in the National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988. database identified Oregon strains as genotypically unique (6,16). We have not identified an environmental source of C. gattii within Oregon or any isolate possessing the same MLST profile as the Oregon clinical strains. Oregon strains could represent an independent population; alternatively, they may have evolved from the VGIIa or VGIIb strains previously described in BC or from VGIIa strains from California (6,9,16), either through random genetic drift genetic drift: see genetics.
Change in the pool of genes of a small population that takes place strictly by chance. Genetic drift can result in genetic traits being lost from a population or becoming widespread in a population without or through sexual recombination recombination, process of "shuffling" of genes by which new combinations can be generated. In recombination through sexual reproduction, the offspring's complete set of genes differs from that of either parent, being rather a combination of genes from both parents. . Recent studies suggest that same-sex mating can occur among cryptococcal isolates and that the VGIIa genotype may have arisen from same-sex mating between a strain of the VGIIb genotype and another unknown strain (16,22).
C. gattii infections have been shown in human and animal residents of the BC lower mainland and in Washington and Oregon in the United States, despite no contact with Vancouver Island or other known disease-endemic areas. These findings may represent an expansion of recognized areas where the disease is endemic.
We thank Sally Lester and veterinarians Veterinarians and veterinary surgeons (vets) are medical professionals who operate exclusively on animals. Well-known and notable veterinarians include:
Julie Hatch, Tasha Poissant, and Paul R. Cieslak are funded through the US Centers for Disease Control and Prevention's Emerging Infections Program Cooperative Agreement (5 U01 CI000306). Funding for environmental sampling was provided by the Michael Smith Foundation for Health Research, Canadian Institutes of Health Research Canadian Institutes of Health Research (CIHR) is the major federal agency responsible for funding health research in Canada. It is the successor to the Medical Research Council of Canada. , BC Lung Association, and BC Medical Services Foundation.
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Laura MacDougall, * Sarah E. Kidd, ([dagger]) Eleni Galanis, * Sunny Mak, * Mira J. Leslie, ([doubledagger]) Paul R. Cieslak, [section] James W. Kronstad, ([dagger]) Muhammad G Morshed, * and Karen H. Bartlett ([dagger])
* British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada; ([dagger]) University of British Columbia Locations
The Vancouver campus is located at Point Grey, a twenty-minute drive from downtown Vancouver. It is near several beaches and has views of the North Shore mountains. The 7. , Vancouver, British Columbia, Canada; ([doubledagger]) Washington State Department of Health, Shoreline, Washington, USA; and ([section]) Oregon State Public Health, Portland, Oregon, USA
Ms MacDougall is surveillance epidemiologist at the British Columbia Centre for Disease Control, Vancouver, British Columbia, Canada. Her research interests include the emergence of C. gattii in British Columbia and the magnitude and determinants of gastrointestinal illness underreporting.
Address for correspondence: Laura MacDougall, British Columbia Centre for Disease Control, 655 W 12th Ave, Vancouver, British Columbia, Canada V5Z 4R4; email: email@example.com
Table 1. Summary of sampling results from locations off Vancouver Island * BC Gulf Washington, Oregon, Sample type mainland Islands USA USA Total Air 196 91 11 6 304 Negative 191 91 11 6 299 Positive (%) 5 (3) 0 0 0 5 (2) Soil 408 250 28 95 781 Negative 408 217 27 95 747 Positive (%) 0 33 (13) 1 (4) 0 34 (4) Swab 521 272 38 94 925 Negative 521 253 37 94 905 Positive (%) 0 19 (7) 1 (3) 0 20 (2) Water 15 6 -- 2 23 Negative 15 5 -- 2 22 Positive (%) 0 1 (17) -- 0 1 (4) Total 1,140 619 77 197 2,033 Negative 1,135 566 75 197 1,973 Positive (%) 5 (0) 53 (9) 2 (3) 0 60 (3) * BC, British Columbia. Table 2. Detected concentration of Cryptococcus gattii in positive soil and air samples from British Columbia and Washington * Concentration of Vancouver BC Disease-endemic C. gattii Island mainland Gulf Island In soil (CFU/g) N 143 0 31 Geometric mean 193.7 -- 632 Geometric SD 6.5 -- 14.2 Range 10-36,350 -- 24-192,952 In air (CFU/[m.sup.3]) for comparable months of the year N 24 5 0 Geometric mean 43.3 10.8 -- Geometric SD 4.6 2.7 -- Range 2-875 5-38 -- Concentration of Other Washington, C. gattii Gulf Islands USA In soil (CFU/g) N 2 1 Geometric mean 33.9 70.8 Geometric SD 1.5 -- Range 24.8-45.5 -- In air (CFU/[m.sup.3]) for comparable months of the year N 0 0 Geometric mean -- -- Geometric SD -- -- Range -- -- * BC, British Columia; SD, standard deviation. Table 3. Geographic location and molecular type associated with clinical and environmental isolates from locations off Vancouver Island * Isolate Date ([dagger]) Host Residence Geographic grid Human 1 Dec 2004 Human BC mainland NTS 092G/05 2 Mar 2005 Human BC mainland NTS 092G/07 3 Mar 2005 Human BC mainland NTS 092G/02 4 2005 ([double Human Oregon USGS 44123-A1B4 dagger]) 5 Dec 2005 Human Oregon USGS 45122-C5D8 Animal 1 Nov 2003 Llama BC mainland NTS 092G/01 2 Mar 2004 Cat BC mainland NTS 092G/01 3 May 2004 Cat BC mainland NTS 092G/01 4 Aug 2004 Cat BC mainland NTS 092G/01 5 Nov 2004 Cat BC mainland NTS 092G/01 6 Mar 2005 Cat BC mainland NTS 092G/03 7 Sep 2005 Ferret BC mainland NTS 092G/06 8 2005 ([double Cat BC mainland NTS 092G/01 dagger]) 9 Jul 2004 Cat Washington USGS 48122-G1H4 10 Jan 2005 Cat Washington USGS 48122-G1H4 11 Apr 2005 Cat Washington USGS 48122-G1H4 Representative environmental isolates (of 60 total) -- Oct 2002 Air BC mainland NTS 092G/02 -- Oct 2002 Air BC mainland NTS 092G/02 -- Jul 2004 Air BC mainland NTS 092G/02 -- Jul 2004 Air BC mainland NTS 092G/01 -- Jul 2004 Air BC mainland NTS 092G/01 -- Mar 2004 Swab, tree Gulf Islands 092B/14 -- Mar 2004 Soil Gulf Islands 092B/14 -- Feb 2005 Swab, tree Gulf Islands 092B/14 -- Jun 2005 Soil Gulf Islands 092B/10 -- Aug 2005 Soil Gulf Islands 092B/14 -- Sep 2005 Swab, Washington USGS 48122-G1H4 fence post -- Oct 2005 Soil Washington USGS 48122-G1H4 Culture/ Molecular Isolate Host specimen no. Serotype type Human 1 Human A4MR410 B VGI 2 Human A5MF738 B VGIIa 3 Human A5MR57 B VGIIa 4 Human KB11632 B VGIIa ([section]) 5 Human A6MR38 B VGIIb ([section]) Animal 1 Llama KB7092 B VGIIa 2 Cat KB8174 B VGIIa 3 Cat KB8686 B VGIIa 4 Cat KB10645 B VGIIa 5 Cat KB11242 B VGIIa 6 Cat KB11765 B VGIIa 7 Ferret KB14724 B VGIIa 8 Cat KB15181 B VGIIa 9 Cat 2004-7975 B VGIIa ([paragraph]) 10 Cat 2005-0550 B VGIIa ([paragraph]) 11 Cat 2005-4659 B VGIIa ([paragraph]) Representative environmental isolates (of 60 total) -- Air KB2045 B VGIIa -- Air KB2241 B VGIIa -- Air KB9057 B VGIIa -- Air KB9101 B VGIIa -- Air KB9091# B -- -- Swab, tree KB7892 B VGI -- Soil KB7893 B VGIIa -- Swab, tree KB11363 B VGI -- Soil KB12611 B VGIIa -- Soil KB13866 B VGIIa -- Swab, KB14489 B VGIIa fence post -- Soil KB14735 B VGIIa * BC, British Columbia; NTS, National Topographic System of Canada; USGS, US Geological Survey. ([dagger]) Date of diagnosis for human and animal case-patients; date of sample for environmental isolates. ([double dagger]) Month unknown. ([section]) Multilocus sequence typing analyses showed differences between these isolates and characterized VGIIa and VGIIb strains from British Columbia. ([paragraph]) DNA isolated from formalin-fixed, paraffin-embedded tissue. # Isolate could not be cleaned from contaminants. Not retained. Table 4. Multilocus sequence typing (MLST) profiles of representative VGII strains from Vancouver Island compared with Cryptococcus gattii isolates from clinical and environmental sources in other locations * MLST profiles Culture RFLP no. Origin Source genotype URA5 LAC A1M R265 VI Human VGIIa 5 ([dagger]) 3 ([dagger]) A1M R272 VI Human VGIIb 7 ([double 3 dagger]) A5M R57 LM Human VGIIa 5 3 A5M F738 LM Human VGIIa 5 3 KB7092 LM Animal VGIIa 5 3 KB11765 LM Animal VGIIa 5 3 KB2045 LM Air VGIIa 5 3 KB13866 GI Soil VGIIa 5 3 KB11377 GI Soil VGIIa 5 3 KB14489 WA Fence VGIIa 5 3 post KB14735 WA Soil VGIIa 5 3 KB11632 OR Human VGIIa 12 ([section]) 3 A6M R38 OR Human VGIIb 11 ([paragraph]) 3 MLST profiles Culture no. FTR1 CAP1 PLB1 IGS A1M R265 4 ([dagger]) 2 ([dagger]) 1 ([dagger]) 1 ([dagger]) A1M R272 4 3 ([double 2 ([double 2 ([double dagger]) dagger]) dagger]) A5M R57 4 2 1 1 A5M F738 4 2 1 1 KB7092 4 2 1 1 KB11765 4 2 1 1 KB2045 4 2 1 1 KB13866 4 2 1 1 KB11377 4 2 1 1 KB14489 4 2 1 1 KB14735 4 2 1 1 KB11632 4 2 1 1 A6M R38 9 4 # 1 3 ([paragraph]) ([paragraph]) * RFLP, restriction fragment length polymorphism; VI, Vancouver Island; LM, British Columbia lower mainland; GI, Gulf Islands; WA, northern Washington, USA; OR, Oregon, USA. ([dagger]) Representative sequence accession nos.: URA5 = AY973136, LAC = AY973094, FTR1 = AY972024, CAP1 = AY971991, PLB1 = DQ777861, IGS = DQ777859. ([double dagger]) Representative sequence accession nos.: URA5 = AY973141, CAP1 = AY971981, PLB1 = DQ777862, IGS = DQ777860. ([section]) Accession no. for unique sequences: URA5 = DQ777864. ([paragraph]) Accession no. for unique sequences: URA5 = DQ777863, FTR1 DQ777857, IGS DQ777858. # Representative sequence accession no.: CAP1 = AY971973.