The Colorado Department of Agriculture has introduced a mandatory statewide surveillance program to sample milk from all licensed commercial dairies.  The objective is to identify all potentially infected herds.

The surveillance program will be administered jointly by the Colorado Department of Agriculture and the Colorado Department of Public Health and the Environment, with support from the USDA.  All licensed dairy-cow facilities producing milk will be required to provide samples each week to be collected by state-certified technicians to be assayed by the Colorado State University Veterinary Diagnostic Laboratory.

Currently in the U.S. there have been more than 170 dairy herds confirmed as infected with bovine influenza H5N1, many of which have recovered.  Colorado has confirmed 47 cases. In the absence of structured surveillance, and based on the presence of RNA fragments in commercial milk the infection appears to be widespread the U.S. extending beyond the current 13 states. Without knowledge of the extent of infection and acquiring temporal and spatial parameters it will be difficult to develop appropriate preventive strategies. 

Virologists and epidemiologists have pointed to the need to suppress bovine influenza H5N1 since there is the potential for emergence of a zoonotic strain that could even become contagious. This would result in a U.S. epidemic and could extend to a worldwide pandemic. The World Health Organization and a wide range of epidemiologists and virologists in public health and academia urge suppression of the infection among dairy herds in the U.S. 

Among many problems relating to bovine influenza is the documented extension of infection to mammalian species including cats, mice in addition to evidence of transmission back to poultry farms. This is evidenced by an extensive outbreak in Michigan and more recently in two egg production complexes in Weld County, CO., all infected with the bovine-adapted H5N1 virus.

Colorado Commissioner of Agriculture Kate Greenberg stated, “Mandatory surveillance of highly pathogenic avian influenza across all Colorado Grade A commercial dairies is a critical next step to tamping down the virus and protecting the food system.  Ongoing cooperation is key to supporting worker health and safety, protecting animal health and welfare and minimizing the spread of the virus.”

USDA-APHIS initiated a program of control requiring bulk milk sampling from a herd before interstate movement of lactating cows.  This is an inadequate and self-serving requirement that ignores the possibility of dissemination of virus by dry cows and heifers and does not address intrastate movement of dairy animals.

Regulatory officials in some states have adopted an ostrich-like response ignoring the potential danger of zoonotic infection relying on pasteurization to inactivate virus in milk.  The Commissioner of Agriculture in one state characterized the need for surveillance of workers by CDC as “overreach.” Many of the 13 states affected have essentially failed to implement programs of detection such as those developed for Colorado and Michigan. Regulatory agencies in these two states support the intermediate and long-term interests of farmers and consumers. Suppression of bovine-influenza is a public health imperative.