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<OL> <LI> Define temporal (and shedding, when appropriate) distributions of ENDV infection states, ie latent, subclinically and clinically infectious, and immune. <LI> Determine non-commercial and commercial locations and flock sizes of the non-commercial and commercial poultry population in southern California.<LI>Estimate modeling parameters, such as typical distance birds travel and frequency of contact among flocks. <LI> Evaluate alternative control (highest risk- and ring-depopulation and vaccination) strategies, comparing epidemic size, duration and cost.
NON-TECHNICAL SUMMARY: Exotic Newcastle disease (END) infection in chickens has up to 100ase-fatality, greater than 90ase-morbidity when chickens are unvaccinated, and can cause a severe reductions in egg production in infected chickens. The purpose of this research is to evaluate (via simulation modeling)control/eradication of END, if it were introduced again into California.
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APPROACH: Proposed research will utilize data already collected in addition to that provided from ongoing work by the Newcastle disease task force. A spatial, epidemic simulation model capable of considering geographic flock location data sets and bird contact information will consider alternative vaccination and depopulation strategies. The epidemic size and duration, using alternative vaccination and depopulation strategies, will be compared. A comprehensive cost-benefit analysis, considering specific controls and associated costs and benefits, will be completed. Data analyses will be performed as previously for the FMD model work. <BR> <BR> In brief, experimental data and expert opinions will be used to estimate virus transmission and disease state statistical distributions. Distribution fits will be tested using the three goodness of fit criteria, chi-square, Anderson and Darling (AD), and Kolmogorov-Smirnoff (KS) (obj. 1). END task force data and additional prospective post-outbreak data will be used to for geocoding premises using ArcView (obj. 2). Questionnaires will be mailed or administered in person by CDFA personnel and results summarized statistically as we reported previously.6,15 Parameters to be estimated include: frequency and range of animal movements to and from premises, frequency of visits by animal health personnel and the range of flocks visited during the previous three days, frequency of visits by delivery vehicles and the range of flocks visited during the previous three days, and requency that flocks have contact, both directly and indirectly, with other flocks. Distribution fits will be tested using C2, AD and KS goodness of fit criteria (obj. 3). Simulation modeling will be conducted using information from objectives 1-3. Results from different control alternatives will be tested using the Kruskal-Wallis multiple comparison test (obj. 4).
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PROGRESS: 2004/05 TO 2008/09<BR>
OUTPUTS: Live bird markets (LBMs) have been associated with outbreaks of infectious diseases. Responses to a detailed questionnaire on the practices and characteristics of LBM partipants in Southern California were analyzed. Compliance to an infectious disease control program that contains active surveillance, prevention, and rapid response measures by those involved in the LBM system, rendering services to dispose of carcasses, no wholesalers and few third party bird deliveries were associated with the lack of exotic Newcastle disease virus circulating the Southern California LBM system. No exotic Newcastle disease virus has been detected in California LBM systems. <BR> <BR>
IMPACT: 2004/05 TO 2008/09<BR>
Results of information gained about the structure and biosecurity practices of live bird markets in Southern California will enable us to better evaluate surveillance and sampling programs, which will in turn better prepare us for identification and eradication of exotic disease agents, such as exotic Newcastle disease virus.