Nicola Marsden-Haug

Cryptococcus gattii in the United States: Clinical Aspects of Infection With an Emerging Pathogen

BACKGROUND Cryptococcus gattii (Cg) has caused increasing infections in the US Pacific Northwest (PNW) since 2004. We describe this outbreak and compare clinical aspects of infection in the United States among patients infected with different Cg genotypes. METHODS Beginning in 2005, PNW state health departments conducted retrospective and prospective passive surveillance for Cg infections, including patient interviews and chart reviews; clinical isolates were genotyped at the US Centers for Disease Control and Prevention (CDC). We examined symptom frequency and underlying conditions in US patients with Cg infection and modeled factors associated with death. RESULTS From 1 December 2004 to July 2011, 96 Cg infections were reported to the CDC. Eighty-three were in patients in or travelers to the PNW, 78 of which were genotypes VGIIa, VGIIb, or VGIIc (outbreak strains). Eighteen patients in and outside the PNW had other molecular type Cg infections (nonoutbreak strains). Patients with outbreak strain infections were more likely than those with nonoutbreak-strain infections to have preexisting conditions (86% vs 31%, respectively; P < .0001) and respiratory symptoms (75% vs 36%, respectively; P = .03) and less likely to have central nervous system (CNS) symptoms (37% vs 90%, respectively; P = .008). Preexisting conditions were associated with increased pneumonia risk and decreased risk of meningitis and CNS symptoms. Nineteen (33%) of 57 patients died. Past-year oral steroid use increased odds of death in multivariate analysis (P = .05). CONCLUSIONS Clinical differences may exist between outbreak-strain (VGIIa, VGIIb, and VGIIc) and nonoutbreak-strain Cg infections in the United States. Clinicians should have a low threshold for testing for Cg, particularly among patients with recent travel to the PNW.

Valley fever: finding new places for an old disease: Coccidioides immitis found in Washington State soil associated with recent human infection.

We used real-time polymerase chain reaction and culture to demonstrate persistent colonization of soils by Coccidioides immitis, an agent of valley fever, in Washington State linked to recent human infections and located outside the endemic range. Whole-genome sequencing confirmed genetic identity between isolates from soil and one of the case-patients.

Whole Genome Sequence Analysis of Cryptococcus gattii from the Pacific Northwest Reveals Unexpected Diversity

A recent emergence of Cryptococcus gattii in the Pacific Northwest involves strains that fall into three primarily clonal molecular subtypes: VGIIa, VGIIb and VGIIc. Multilocus sequence typing (MLST) and variable number tandem repeat analysis appear to identify little diversity within these molecular subtypes. Given the apparent expansion of these subtypes into new geographic areas and their ability to cause disease in immunocompetent individuals, differentiation of isolates belonging to these subtypes could be very important from a public health perspective. We used whole genome sequence typing (WGST) to perform fine-scale phylogenetic analysis on 20 C. gattii isolates, 18 of which are from the VGII molecular type largely responsible for the Pacific Northwest emergence. Analysis both including and excluding (289,586 SNPs and 56,845 SNPs, respectively) molecular types VGI and VGIII isolates resulted in phylogenetic reconstructions consistent, for the most part, with MLST analysis but with far greater resolution among isolates. The WGST analysis presented here resulted in identification of over 100 SNPs among eight VGIIc isolates as well as unique genotypes for each of the VGIIa, VGIIb and VGIIc isolates. Similar levels of genetic diversity were found within each of the molecular subtype isolates, despite the fact that the VGIIb clade is thought to have emerged much earlier. The analysis presented here is the first multi-genome WGST study to focus on the C. gattii molecular subtypes involved in the Pacific Northwest emergence and describes the tools that will further our understanding of this emerging pathogen.

Presence and Persistence of Coxiella burnetii in the Environments of Goat Farms Associated with a Q Fever Outbreak

ABSTRACT Q fever is a zoonotic disease caused by inhalation of the bacterium Coxiella burnetii. Ruminant livestock are common reservoirs for C. burnetii, and bacteria present in aerosols derived from the waste of infected animals can infect humans. The significance of infection from material deposited in the environment versus transmission directly from infected animals is not known. In 2011, an outbreak of Q fever cases on farms in Washington and Montana was associated with infected goats. A study was undertaken to investigate the quantity and spatial distribution of C. burnetii in the environment of these goat farms. Soil, vacuum, and sponge samples collected on seven farms epidemiologically linked to the outbreak were tested for the presence of C. burnetii DNA by quantitative PCR. Overall, 70.1% of the samples were positive for C. burnetii. All farms had positive samples, but the quantity of C. burnetii varied widely between samples and between farms. High quantities of C. burnetii DNA were in goat housing/birthing areas, and only small quantities were found in samples collected more than 50 m from these areas. Follow-up sampling at one of the farms 1 year after the outbreak found small quantities of C. burnetii DNA in air samples and large quantities of C. burnetii persisting in soil and vacuum samples. The results suggest that the highest concentrations of environmental C. burnetii are found in goat birthing areas and that contamination of other areas is mostly associated with human movement.

Cryptococcus gattii in the United States: Genotypic Diversity of Human and Veterinary Isolates

Background Cryptococcus gattii infections are being reported in the United States (US) with increasing frequency. Initially, US reports were primarily associated with an ongoing C . gattii outbreak in the Pacific Northwest (PNW) states of Washington and Oregon, starting in 2004. However, reports of C . gattii infections in patients from other US states have been increasing since 2009. Whether this is due to increasing frequency of disease, greater recognition within the clinical community, or both is currently unknown. Methodology/Principal Findings During 2005–2013, a total of 273 C . gattii isolates from human and veterinary sources in 16 US states were collected. Of these, 214 (78%) were from the Pacific Northwest (PNW) and comprised primarily the clonal C . gattii genotypes VGIIa (64%), VGIIc (21%) and VGIIb (9%). The 59 isolates from outside the PNW were predominantly molecular types VGIII (44%) and VGI (41%). Genotyping using multilocus sequence typing revealed small clusters, including a cluster of VGI isolates from the southeastern US, and an unrelated cluster of VGI isolates and a large cluster of VGIII isolates from California. Most of the isolates were mating type MATα, including all of the VGII isolates, but one VGI and three VGIII isolates were mating type MATa . Conclusions/Significance We provide the most comprehensive report to date of genotypic diversity of US C . gattii isolates both inside and outside of the PNW. C . gattii may have multiple endemic regions in the US, including a previously-unrecognized endemic region in the southeast. Regional clusters exist both in California and the Southeastern US. VGII strains associated with the PNW outbreak do not appear to have spread substantially beyond the PNW.

Epidemiologic cutoff values for triazole drugs in Cryptococcus gattii: correlation of molecular type and in vitro susceptibility

Cryptococcus gattii causes infection in tropical and subtropical regions worldwide but has garnered increased attention since its 1999 emergence in North America. C. gattii can be divided into 4 molecular types that may represent cryptic species. Recent evidence has shown that azole antifungal MIC values differ among these molecular types. We tested a large collection of C. gattii isolates for susceptibility to 4 azole drugs. We found that isolates of molecular type VGII have the highest geometric mean (GM) fluconazole MIC values (8.6 μg/mL), while isolates of molecular type VGI have the lowest (1.7 μg/mL). For fluconazole, itraconazole, and voriconazole GM MIC values, VGI < VGIII < VGIV < VGII. The GM MIC values for posaconazole were similarly represented across molecular types, with the exception that VGII < VGIII and VGIV. We used the MIC values to establish preliminary epidemiologic cutoff values for each azole and molecular type of C. gattii.

Treatment and outcomes among patients with Cryptococcus gattii infections in the United States Pacific Northwest.

Background Cryptococcus gattii is a fungal pathogen causing an emerging outbreak in the United States Pacific Northwest (PNW). Treatment guidelines for cryptococcosis are primarily based on data from C. neoformans infections; applicability to PNW C. gattii infection is unknown. We evaluated the relationship between initial antifungal treatment and outcomes for PNW C.gattii patients. Methods Cases were defined as culture-confirmed invasive C. gattii infections among residents of Oregon and Washington States during 2004–2011. Clinical data were abstracted from medical records through one year of follow-up. Recommended initial treatment for central nervous system (CNS), bloodstream, and severe pulmonary infections is amphotericin B and 5-flucytosine; for non-severe pulmonary infections, recommended initial treatment is fluconazole. Alternative initial treatment was defined as any other initial antifungal treatment. Results Seventy patients survived to diagnosis; 50 (71%) received the recommended initial treatment and 20 (29%) received an alternative. Fewer patients with pulmonary infections [21 (64%)] than CNS infections [25 (83%)] received the recommended initial treatment (p = 0.07). Among patients with pulmonary infections, those with severe infections received the recommended initial treatment less often than those with non-severe infections (11% vs. 83%, p<0.0001). Eight patients with severe pulmonary infections received alternative initial treatments; three died. Four patients with non-severe pulmonary infections received alternative initial treatments; two died. There was a trend towards increased three-month mortality among patients receiving alternative vs. recommended initial treatment (30% vs. 14%, p = 0.12), driven primarily by increased mortality among patients with pulmonary disease receiving alternative vs. recommended initial treatment (42% vs. 10%, p = 0.07). Conclusions C.gattii patients with pulmonary infections – especially severe infections – may be less likely to receive recommended treatment than those with CNS infections; alternative treatment may be associated with increased mortality. Reasons for receipt of alternative treatment among C.gattii patients in this area should be investigated, and clinician awareness of recommended treatment reinforced.

Epidemiology of Lyme disease in low-incidence states

Lyme disease is the most common vector-borne disease in the U.S. Surveillance data from four states with a low-incidence of Lyme disease was evaluated. Most cases occurred after travel to high-incidence Lyme disease areas. Cases without travel-related exposure in low-incidence states differed epidemiologically; misdiagnosis may be common in these areas.

Age as an independent risk factor for intensive care unit admission or death due to 2009 pandemic influenza A (H1N1) virus infection.

Objective. This study evaluated risk factors for intensive care unit (ICU) admission or death among people hospitalized with 2009 pandemic influenza A (pH1N1) virus infection. Methods. We based analyses on data collected in Washington State from April 27 to September 18, 2009, on deceased or hospitalized people with laboratory-confirmed pH1N1 infection reported by health-care providers and hospitals as part of enhanced public health surveillance. We used bivariate analyses and multivariable logistic regression to identify risk factors associated with ICU admission or death due to pH1N1. Results. We identified 123 patients admitted to the hospital but not an ICU and 61 patients who were admitted to an ICU or died. Independent of high-risk medical conditions, both older age and delayed time to hospital admission were identified as risk factors for ICU admission or death due to pH1N1. Specifically, the odds of ICU admission or death were 4.44 times greater among adults aged 18–49 years (95% confidence interval [CI] 1.97, 10.02) and 5.93 times greater among adults aged 50–64 years (95% CI 2.24, 15.65) compared with pediatric patients <18 years of age. Likewise, hospitalized cases admitted more than two days after illness onset had 2.17 times higher odds of ICU admission or death than those admitted within two days of illness onset (95% CI 1.10,4.25). Conclusion. Although certain medical conditions clearly influence the need for hospitalization among people infected with pH1N1 virus, older age and delayed time to admission each played an independent role in the progression to ICU admission or death among hospitalized patients.

Epidemiology Competency Development and Application to Training for Local and Regional Public Health Practitioners

In 2002, the Northwest Center for Public Health Practice (NWCPHP) at the University of Washington initiated the Epidemiology Competencies Project, with the goal of developing competency-based epidemiology training for non-epidemiologist public health practitioners in the northwestern United States. An advisory committee consisting of epidemiology faculty and experienced public health practitioners developed the epidemiology competencies. NWCPHP used the competencies to guide the development of in-person trainings, a series of online epidemiology modules, and a Web-based repository of epidemiology teaching materials. The epidemiology competencies provided a framework for collaborative work between NWCPHP and local and regional public health partners to develop trainings that best met the needs of a particular public health organization. Evaluation surveys indicated a high level of satisfaction with the online epidemiology modules developed from the epidemiology competencies. However, measuring the effectiveness of competency-based epidemiology training for expanding epidemiology knowledge and skills of the public health workforce remains a challenge.