Veterinary Epidemiology and Zoonosis

SENTINEL SURVEILLANCE

• Surveillance can include entire national herd.
  • Example: Testing of bovine tuberculosis.
• Alternatively, a few farms, abattoirs, veterinary practices or laboratories may be selected; these are then referred to as sentinel units, because they are designed to keep watch on disease. Thus, sentinel equine premises can be used to investigate persistence of vesicular stomatitis virus, using previous history of the disease as the selection criterion.
• Alternatively, attention may be focused on a species in general. Thus, horses can be used as sentinels for Venezuelan equine encephalitis infection and stray dogs can be sentinels for canine parvo virus infection, the infection being identified serologically.
• Domestic animals also can be used as sentinels of human environmental health hazards such as carcinogens and insecticides.
  • Example: Eastern equine encephalitis infects horses and other vertebrates, including man, but has a reservoir in birds.
• Surveillance of this infection therefore includes regular serological testing of sentinel flocks of chickens or pheasants kept outdoors in association with the result of virus culture on captured mosquitoes, and veterinary surveillance in Eastern equine encephalitis illness in horses.