Animal Categorization Scheme
To support analyses of outbreaks reported through the Animal Contact Outbreak Surveillance System (ACOSS), CDC categorizes animals into three increasingly specific levels: biologic class, major group, and subgroup. This animal categorization scheme helps public health, regulatory, and animal health professionals use ACOSS data to
- describe which animal categories are most often linked to enteric (intestinal) disease outbreaks
- identify animals that spread the (bacteria, viruses, or parasites) causing the most outbreak-related illnesses
- improve understanding of outbreak characteristics linked to specific animal categories
- inform recommendations and policies
- assess prevention strategies and measure progress in disease prevention
The levels are based on each animal’s biological characteristics, common settings of exposure, or interactions with humans. For example, a wild dog would be classified as:
Level 1 (Biologic Class): Mammal
Level 2 (Major Group): Canine
Level 3 (Subgroup): Wild canine
Categorizing animals is part of a larger initiative to improve the collection, quality, and usefulness of data from animal contact outbreaks. This work could be expanded to include animals that transmit non-enteric pathogens.
*Domesticated birds kept by humans for their eggs, meat, or feathers.
This animal categorization scheme reflects a collaborative effort among CDC’s Enteric Diseases Epidemiology Branch, One Health Office, and Outbreak Response and Prevention Branch; the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service; and the Food and Drug Administration’s Center for Food Safety and Applied Nutrition. The structure and goals of the scheme align with those of the Interagency Food Safety Analytics Collaboration (IFSAC) Food Categorization Scheme published in 2017, which is used to characterize foods linked to outbreaks.