This movement was legal since the farm was located outside a control zone but subsequently yielded H5N2 HPAI on surveillance sampling. Accordingly APHIS is conducting a trace-forward evaluation and surveillance of recipient flocks.
The report on the epidemiology of the current outbreak will be released during the week of June 15th. The report will contain preliminary results relating to field observations and the responses from questionnaires obtained by interview of turkey producers. Geospatial investigations are in progress with specific reference to the possibility of airborne spread. On-farm investigations have disclosed the presence of airborne HPAI virus at a distance of 1,000 m downwind from an infected farm. Wind direction, duration and speed will be evaluated. Preliminary data suggests that sustained winds for over two days at over 30 mph may have been responsible for some inter-farm transmission.
Phylogenetic assays conducted by the National Veterinary Services Laboratory have shown only minor differences in the genetic sequences of H5N2 isolates which can be related to specific clusters of cases. Case-control studies are in progress with specific reference to turkey growing farms in Minnesota and large in-line breaking complexes in Iowa.
A cooperating integrator in Minnesota is providing detailed data on movement of vehicles during the outbreak. This is undergoing analysis in relation to the sequence and location of cases involving turkey farms.
The USDA-APHIS will conduct a planning session at the end of June to consider a worst-case scenario under which migratory waterfowl and shore birds introduce virus into all four flyways in the Fall of 2015 and by inference during the Spring of 2016. Preliminary analysis of models has disclosed that in a doomsday scenario, 500 commercial farms would be affected in 20 states. This compares to the approximately 200 commercial premises involved in the Spring 2015 outbreaks.
Future policy will be guided by epidemiology reports and surveillance of waterfowl which will commence in July. The Fall Meeting will also consider available assets and apparent logistic deficiencies presented by the challenges of diagnosis, euthanasia, depletion and disposal especially of caged hens in Iowa, Nebraska and Minnesota.
A meeting will take place in Des Moines IA on July 28th to review aspects of biosecurity. It is hoped that the USDA will be able to provide guidance based on the reports on the status of the outbreak and the results of epidemiologic studies.
The USDA noted that more data would be required on the efficacy of vaccines but APHIS is reviewing the conditions which might trigger the release of vaccines.
The U.S. Senate Agriculture Committee has scheduled a hearing on July 7th to review aspects of the response by USDA-APHIS to the Spring outbreak. Public comments made by the Iowa
Congressional representation suggests that APHIS Administrators will be quizzed on preparedness and their ability to forecast the magnitude of outbreaks.