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The epidemic of foot-and-mouth disease in Saskatchewan, Canada, 1951-1952
1Agriculture Canada, Health of Animals Laboratory Branch, Ottawa, Ontario.
Abstract:
The epidemic of foot-and-mouth disease in Saskatchewan in 1951 and 1952 was studied in order to determine origins of outbreaks and methods of spread. The epidemic was initially considered to be vesicular stomatitis and foot-and-mouth disease was not recognized until February 1952, three months after the initial infection. The reports prepared at that time were reviewed in order to obtain details of the numbers of animals infected and the source and date of infection for the outbreaks. Methods of spread were rated according to their likelihood. The introduction of infection by an immigrant through his clothes as well as by sausage was possible. The sequence of events from the first outbreak to the spread from a feedlot/packing plant and from a dairy farm, which failed to report the disease, were clarified. Methods of spread included movement of animals, animal products and people and the airborne route. Milk delivery and artificial insemination did not result in spread of infection. The quarantine of affected farms reduced spread by animals and deterred visits by people. The original diagnosis of vesicular stomatitis was due to misinterpretation of a lesion in an inoculated horse. Laboratory tests established the presence of foot-and-mouth disease. The limited extent of the epidemic, despite the delay in diagnosis, is attributed to (i) the low density of cattle, (ii) few infected pigs and hence less airborne virus and (iii) absence of waste food feeding and milk collection in addition to the limited quarantine imposed.
Insights
The 1951-1952 Saskatchewan foot-and-mouth disease epidemic was investigated to identify outbreak origins and spread. Delayed diagnosis did not cause widespread transmission due to factors like low cattle density and effective quarantine measures.
Area of Science:
- Veterinary Epidemiology
- Infectious Disease Dynamics
- Public Health Surveillance
Background:
- The 1951-1952 Saskatchewan epidemic was initially misdiagnosed as vesicular stomatitis.
- Foot-and-mouth disease (FMD) was confirmed three months after the initial infection, delaying control efforts.
Purpose of the Study:
- To determine the origins and primary transmission routes of the FMD epidemic in Saskatchewan.
- To analyze the factors influencing the spread and containment of the FMD outbreak.
Main Methods:
- Review of historical outbreak reports detailing animal infections, sources, and dates.
- Assessment of potential transmission pathways, including animal movement, contaminated products, and airborne spread.
- Analysis of implemented control measures, such as farm quarantine.
Main Results:
- Potential introduction routes included an immigrant's clothing and contaminated sausage.
- Spread occurred via animal movement, products, people, and airborne transmission from feedlots/packing plants and unreported dairy farms.
- Milk delivery and artificial insemination were not significant transmission routes.
Conclusions:
- Effective quarantine, low cattle density, limited pig involvement (reducing airborne virus), and absence of swill feeding contributed to limiting the epidemic's extent.
- Despite delayed diagnosis, the epidemic's limited spread was attributed to a combination of epidemiological factors and control measures.