Study Subjects
Only farms with 100 or fewer pigs were included
Classified as commercial and non-commercial
Primary outbreaks were included, excluding secondary cases
Case and Control Matching
Two pig farms without an outbreak are selected as controls<br>
Matched according to location, herd size and breeding type
Maximum distance between case and control farms was defined as 25 km
Selection of Control Farms
Online map tool used to measure distance from case farm to adjacent farm<br>
Two farms that met required criteria and were closest to case farm selected<br>
Data Collection Method
Face-to-face interviews conducted by veterinarians from emergency department
Visits to case farms are usually conducted on day of culling or day before
Visual inspections at control farms without entering pen
Data Verification
Data is verified by two people before being used for statistical analysis<br>
Double checking
Data Collection
Collect risk factor data through questionnaires
Includes herd information, pig farm management, biosecurity measures, etc.
Questionnaire is a simplified version of official questionnaire for investigation of African swine fever in Lithuania<br>
