A National Plan for the Control and Eradication of Enzootic Pneumonia in Norwegian Swine Herds

Enzootic pneumonia caused by Mycoplasma hyopneumoniae has a worldwide distribution and causes great losses in the swine industry. Depending on environmental factors, it may cause varying degrees of a bronchopneumonia and will reduce daily weight gain. According to Norwegian and Finnish findings, enzootic pneumonia reduces daily weight gain between 40 and 60 grams per day during the growing period up until slaughter. The disease will also increase the risk for additional lung infections by other pathogens.

In a survey made in 1998, the prevalence of Norwegian swineherds seropositive for M. hyopneumoniae was found to vary between regions, from five percent up to 40 percent. All elite breeding and multiplying herds in Norway are free from the infection. Actinobacillus pleuropneumoniae is prevalent in most Norwegian swineherds. Norway is free from several of the important viral lung pathogens, such as swine influenza virus, PRCV, PRRSV and Aujeszky's Disease virus.

Eradication of enzootic pneumonia has been successful in approximately 90 percent of more than the 100 Norwegian swineherds where eradication programmes have been performed. Most eradications have been performed using the Zimmermann method, where breeding animals older than 10 months are kept in the herd, while younger animals are removed. No farrowings take place during the eradication period. After a thorough cleaning of the premises, all remaining animals are medicated daily with tiamulin in the drinking water for a two-week period.

In 1999, a project was started to eradicate enzootic pneumonia from all swineherds in one region in southern Norway. In 2000, similar projects were started in two other regions, central Norway and northern Norway.

At the end of 2000, most of the herds in these regions have been serologically tested for antibodies against M. hyopneumoniae, and in most of the seropositive herds the disease has been eradicated. Only one herd was known to be positive in the region where the project started, but a few herds remained to be tested. In central and northern Norway, 27 and 4 herds were known to be positive, respectively.

In 2001, a plan was passed to test pigs in all Norwegian swineherds for antibodies against M. hyopneumoniae. During a five-year period, all the remaining un-tested swineherds will be tested. During that period, the disease will be eradicated in all herds in the three regions included in the initial eradication projects as well as in northwestern Norway. Throughout the rest of the country, the eradication will already be in progress.

The parties involved in the project are the slaughterhouse companies, co-operative as well as private, the swine breeders' organisation, and the official veterinary authorities. The Norwegian Pig Health Service, which is organised as cooperation between the mentioned parties along with the Norwegian Veterinary Association and the Veterinary Institute, is the coordinating the project. The slaughterhouse companies, the Norwegian Pig Health Service and the individual farmers involved, finance the plan.