Causes of mortality in backyard poultry in eight states in the United States.

A comprehensive understanding of common diseases of backyard poultry flocks is important to providing poultry health information to flock owners, veterinarians, and animal health officials. We collected autopsy reports over a 3-y period (2015-2017) from diagnostic laboratories in 8 states in the United States; 2,509 reports were collected, involving autopsies of 2,687 birds. The primary cause of mortality was categorized as infectious, noninfectious, neoplasia or lymphoproliferative disease, or undetermined. Neoplasia or lymphoproliferative disease was the most common primary diagnosis and involved 42% of the total birds autopsied; 63% of these cases were diagnosed as Marek's disease or leukosis/sarcoma. Bacterial, parasitic, and viral organisms were commonly detected, involving 42%, 28%, and 7% of the birds autopsied, respectively, with 2 or more organisms detected in 69% of birds. Our findings demonstrate the importance of educating flock owners about disease prevention and biosecurity practices. The detection of zoonotic bacteria including paratyphoid salmonellae, Campylobacter spp., Listeria monocytogenes, and Mycobacterium avium, and the detection of lead and other heavy metals, indicate public health risks to flock owners and consumers of backyard flock egg and meat products.

An approach for de-identification of point locations of livestock premises for further use in disease spread modeling.

We describe a method for de-identifying point location data used for disease spread modeling to allow data custodians to share data with modeling experts without disclosing individual farm identities. The approach is implemented in an open-source software program that is described and evaluated here. The program allows a data custodian to select a level of de-identification based on the K-anonymity statistic. The program converts a file of true farm locations and attributes into a file appropriate for use in disease spread modeling with the locations randomly modified to prevent re-identification based on location. Important epidemiological relationships such as clustering are preserved to as much as possible to allow modeling similar to those using true identifiable data. The software implementation was verified by visual inspection and basic descriptive spatial analysis of the output. Performance is sufficient to allow de-identification of even large data sets on desktop computers available to any data custodian.

An epidemiologic simulation model of the spread and control of highly pathogenic avian influenza (H5N1) among commercial and backyard poultry flocks in South Carolina, United States.

Epidemiologic simulation modeling of highly pathogenic avian influenza (HPAI) outbreaks provides a useful conceptual framework with which to estimate the consequences of HPAI outbreaks and to evaluate disease control strategies. The purposes of this study were to establish detailed and informed input parameters for an epidemiologic simulation model of the H5N1 strain of HPAI among commercial and backyard poultry in the state of South Carolina in the United States using a highly realistic representation of this poultry population; to estimate the consequences of an outbreak of HPAI in this population with a model constructed from these parameters; and to briefly evaluate the sensitivity of model outcomes to several parameters. Parameters describing disease state durations; disease transmission via direct contact, indirect contact, and local-area spread; and disease detection, surveillance, and control were established through consultation with subject matter experts, a review of the current literature, and the use of several computational tools. The stochastic model constructed from these parameters produced simulated outbreaks ranging from 2 to 111 days in duration (median 25 days), during which 1 to 514 flocks were infected (median 28 flocks). Model results were particularly sensitive to the rate of indirect contact that occurs among flocks. The baseline model established in this study can be used in the future to evaluate various control strategies, as a tool for emergency preparedness and response planning, and to assess the costs associated with disease control and the economic consequences of a disease outbreak.

Disseminated Aspergillus flavus infection in broiler breeder pullets.

Increased morbidity and mortality occurred in a 5-wk-old broiler breeder replacement pullet flock. The affected broiler pullet flock was housed on the first floor of a two-story confinement building. Mortality increased to 0.1%/day compared to the flock on the second floor, which had mortality levels of less than 0.01%/day. Clinical signs in the affected chickens included inactivity, decreased response to stimuli, and anorexia. No respiratory or neurologic signs were observed. On necropsy, affected pullets were dehydrated and emaciated and had disseminated variably sized single or multiple heterophilic granulomas that contained intralesional septate and branching fungal hyphae. Lesions were extensive around the base of the heart in the thoracic inlet and in the kidneys. Other affected organs included eyelid, muscle, proventriculus, ventriculus, intestine, liver, spleen, lung, and heart. Aspergillus flavus was cultured from the visceral granulomas. The source of flock exposure to the organism was not determined.