The academic and government research on GWSS and PD received support from the state's viticulture and enology industries and even local government before and during the Temecula Valley outbreak. Industry organizations partnering with CDFA and UC Division of Agriculture and Natural Resources (UC ANR) in these efforts included the American Vineyard Foundation, the California Table Grape Commission, the California Raisin Board and the California Rootstock Commission. UC ANR and CDFA provided coordination to prioritize research, avoid duplication and maximize the collective benefits of the programs. Since 1999, USDA has provided about 75% of the funding for PD control and research, and the state of California, industry and UC have provided the rest. California legislation initiated a statewide assessment on wine grapes to support research and related activities, raising about $46 million to date (Tumber et al. 2014; Wiggins 2001). The timeline here highlights some of the key events in the efforts to contain and find solutions to the PD outbreak in California.

The City of Oakland is the largest city within Alameda County, the 8th largest city in California, and the 45th largest in the United States. Due to various socioeconomic factors, the number of homeless encampments within Oakland has been increasing over the past few years. A recently completed survey showed that there has been a 47.45% increase in the number of homeless living within the city limits. Approximately 4,071 people are now living in various encampments around the city, primarily concentrated underneath freeway/infrastructure overpasses and on adjoining lands. Surveillance by our staff found that several of these encampments also had active Norway rat populations as indicated by active burrows within and adjacent to the camps, as well as resident reports. Beginning in the fall of 2017, District biologists began live-trapping at a few of the larger encampments to try and ascertain the composition and load of ectoparasites on corresponding Norway rat populations. We specifically looked at flea abundance and species composition, as they are vectors of diseases, such as Murine typhus (Rickettsia typhi), flea-borne typhus (Rickettsia felis), and plague (Yersinia pestis). We trapped at four different camps in Oakland over a nine-month period and found that the flea, mite, and louse abundance, along with species composition, varied between the camps. To date, we have yet to determine the causes of these differences, but fleas tested at two of the four camps have come back as positive for R. felis. We are continuing to trap at these camps and are expanding our trapping program to include additional camps in an effort to determine what variables affect the ectoparasite composition on Norway rat populations within the City of Oakland.

Homeless encampments are a persistent feature in the city of Oakland, California. Unsanitary conditions in these camps can contribute to large populations of Norway rats and associated vector-borne disease. Alameda County Vector Control Services District has developed a surveillance program for safe and efficient data collection in these encampments. This program includes outreach to residents, effective live-trap ping, ectoparasite collection, vector species suppression, and coordinating with other agencies. The District’s operations around Oakland’s pilot “Tuff Shed” homeless shelter strategy are presented as a case study for Norway rat and Oriental rat flea risk assessment and control.