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A case-control study was conducted among commercial table-egg layer and pullet operations in Iowa and Nebraska, United States, to investigate potential risk factors for infection with highly pathogenic avian influenza (HPAI) H5N2. A questionnaire was developed and administered to 28 case farms and 31 control farms. Data were collected at the farm and barn levels, enabling two separate analyses to be performed-the first a farm-level comparison of case farms vs. control farms, and the second a barn-level comparison between case barns on case farms and control barns on control farms. Multivariable logistic regression models were fit using a forward-selection procedure. Key risk factors identified were farm location in an existing control zone, rendering and garbage trucks coming near barns, dead-bird disposal located near barns, and visits by a company service person. Variables associated with a decreased risk of infection included visitors changing clothing, cleaning and disinfecting a hard-surface barn entryway, and ceiling/eaves ventilation in barns. Factores asociados con la infección con el virus de influenza altamente patógeno H5N2 en granjas de gallinas de postura comerciales en el medio oeste de Estados Unidos en el año 2015. Se llevó a cabo un estudio de casos y controles en las operaciones de aves de postura comerciales y pollitas en los estados de Iowa y Nebraska en los Estados Unidos, para investigar los posibles factores de riesgo para la infección por el virus de la influenza aviar altamente patógeno H5N2. Se elaboró un cuestionario y se administró en 28 granjas afectadas y 31 granjas control. Los datos fueron recolectados a nivel de granjas y de casetas, lo que permitió que se realizaran dos análisis separados. La primera comparación fue a nivel de granjas entre granjas afectadas y granjas control y la segunda fue una comparación a nivel de casetas entre casetas afectadas de granjas afectadas y casetas control de granjas de control. Se ajustaron los modelos de regresión logística multivariable mediante un procedimiento de selección hacia adelante. Los principales factores de riesgo que fueron identificados incluyeron la ubicación de la granja en una zona de control existente, los camiones de procesado y basura que circulaban cerca de las casetas, la eliminación de aves muertas en proximidad con las casetas y las visitas por las personas de servicio de las compañías. Las variables asociadas con un menor riesgo de infección incluyeron el cambio de ropa de los visitantes, limpieza y desinfección de las entradas de las casetas y de los techos y aleros de ventilación en las casetas. [ABSTRACT FROM AUTHOR]

Fecal samples were collected from pens of cattle in a total of 100 feedlots in 13 states. Fecal samples were cultured for Escherichia coli O157. E. coli O157 isolates were probed for the genetic coding for verotoxin production. At the time of sample collection, data were collected on the type of cattle present in the pen, as well as the length of time these cattle were in the feedlot, ingredients for the current ration, and cattle health history since arriving in the feedlot. Factors associated with increased likelihood of a pen being positive (one or more samples probe-positive for E. coli O157) included feeding of barley (odds ratio [OR] = 2.75) and cattle being on feed less than 20 days (OR = 3.39). Factors associated with a reduced likelihood of a pen being positive included feeding soy meal (OR = 0.50), a cattle entry weight of at least 700 lb (ca. 317.5 kg) (OR = 0.54), and at least 85% of the cattle in the pen being beef-type heifers (OR = .33).