[The leukocyte count is a valuable parameter for detecting classical swine fever]

Area of Science:

• Veterinary Medicine
• Infectious Disease Epidemiology
• Animal Health Diagnostics

Background:

• Classical Swine Fever (CSF) poses a significant threat to swine populations.
• Accurate and timely detection of CSF outbreaks is crucial for disease control.
• The white blood cell count (wbcc) is a potential indicator of infection.

Purpose of the Study:

• To evaluate the efficacy of white blood cell count (wbcc) in detecting Classical Swine Fever (CSF) outbreaks.
• To determine the optimal number of animals and threshold for wbcc testing in field diagnosis.
• To assess the utility of wbcc in conjunction with clinical inspection for CSF detection.

Main Methods:

• Meta-analysis of challenge experiments with different CSF virus (CSFV) strains in pigs.
• Analysis of field data from infected and non-infected herds using Receiver Operating Characteristic (ROC) curves.
• Monte Carlo simulation to determine the optimal sample size for wbcc testing.

Main Results:

• Virulent and moderately virulent CSFV strains caused a significant decrease in wbcc in pigs.
• Mildly virulent CSFV strains did not consistently result in a significant wbcc decrease.
• Testing five animals per herd with a threshold of 8000 leukocytes/mm³ achieved 94.5% herd sensitivity and 97.2% herd specificity for detecting outbreaks caused by moderately virulent strains.

Conclusions:

• White blood cell count (wbcc) is a valuable tool for detecting CSF outbreaks caused by moderately virulent CSFV strains.
• wbcc is less reliable for detecting outbreaks caused by mildly virulent CSFV strains.
• Further development of diagnostic tools is needed to enhance clinical diagnosis of CSF.