Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (3 results)

  • Article
Proceedings of the Vertebrate Pest Conference, Volume 18 (1998)
Hantavirus Pulmonary Syndrome (HPS), a severe and frequently fatal respiratory disease, was first recognized in 1993 during an outbreak of acute illness in the Four Comers area of the southwestern United States. The etiologic agent, Sin Nombre virus (SNV), was identified as a previously unrecognized member of the Hantavirus genus transmitted by rodents, especially members of the genus Peromyscus, which shed SNV in urine and feces. Since 1993, 16 California residents have been diagnosed with HPS, four of these were identified retrospectively with onset prior to 1993. The median age of case-patients was 42 years, 10 were male, and 8 died. Sites of likely exposure for these cases tended to cluster in the eastern Sierra Nevada range. Serologic surveillance of rodents has been conducted prospectively in California since 1993 and retrospectively for specimens collected back to 1975. To date, serologic evidence of infection with SNV has been recognized in 473 (6.6%) of 7,191 rodents from 18 genera, and in 426 (9.6%) of 4,489 Peromyscus spp. At least one seroreactive Peromyscus sp. specimen has been identified in 40 of 46 counties surveyed.
    Cover page: Surveillance for Sin Nombre virus and hantavirus pulmonary syndrome in California, 1993 to 1997
    • Article
    • Peer Reviewed
    Berkeley Research Impact Initiative (BRII) (2009)

    Plague, caused by the bacterium Yersinia pestis, is a public and wildlife health concern in California and the western United States. This study explores the spatial characteristics of positive plague samples in California and tests Maxent, a machine-learning method that can be used to develop niche-based models from presence-only data, for mapping the potential distribution of plague foci. Maxent models were constructed using geocoded seroprevalence data from surveillance of California ground squirrels (Spermophilus beecheyi) as case points and Worldclim bioclimatic data as predictor variables, and compared and validated using area under the receiver operating curve (AUC) statistics. Additionally, model results were compared to locations of positive and negative coyote (Canis latrans) samples, in order to determine the correlation between Maxent model predictions and areas of plague risk as determined via wild carnivore surveillance.

    Results:

    Models of plague activity in California ground squirrels, based on recent climate conditions, accurately identified case locations (AUC of 0.913 to 0.948) and were significantly correlated with coyote samples. The final models were used to identify potential plague risk areas based on an ensemble of six future climate scenarios. These models suggest that by 2050, climate conditions may reduce plague risk in the southern parts of California and increase risk along the northern coast and Sierras.

    Conclusion:

    Because different modeling approaches can yield substantially different results, care should be taken when interpreting future model predictions. Nonetheless, niche modeling can be a useful tool for exploring and mapping the potential response of plague activity to climate change. The final models in this study were used to identify potential plague risk areas based on an ensemble of six future climate scenarios, which can help public managers decide where to allocate surveillance resources. In addition, Maxent model results were significantly correlated with coyote samples, indicating that carnivore surveillance programs will continue to be important for tracking the response of plague to future climate conditions.

      • Article
      • Peer Reviewed
      UC Davis Previously Published Works (2019)
      In July 2017, fever and sepsis developed in 3 recipients of solid organs (1 heart and 2 kidneys) from a common donor in the United States; 1 of the kidney recipients died. Tularemia was suspected only after blood cultures from the surviving kidney recipient grew Francisella species. The organ donor, a middle-aged man from the southwestern United States, had been hospitalized for acute alcohol withdrawal syndrome, pneumonia, and multiorgan failure. F. tularensis subsp. tularensis (clade A2) was cultured from archived spleen tissue from the donor and blood from both kidney recipients. Whole-genome multilocus sequence typing indicated that the isolated strains were indistinguishable. The heart recipient remained seronegative with negative blood cultures but had been receiving antimicrobial drugs for a medical device infection before transplant. Two lagomorph carcasses collected near the donor's residence were positive by PCR for F. tularensis subsp. tularensis (clade A2). This investigation documents F. tularensis transmission by solid organ transplantation.
        Cover page: Ahead of Print - <em>Francisella tularensis</em> Transmission by Solid Organ Transplantation, 2017 - Volume 25, Number 4—April 2019 - Emerging Infectious Diseases journal - CDC
        Top