Recent network evolution increases the potential for large epidemics in the British cattle population.

Area of Science:

• Veterinary epidemiology
• Network science
• Animal health policy

Background:

• Foot and mouth disease epidemic in Great Britain (GB) in 2001 led to livestock movement restrictions.
• Mandatory standstill periods were implemented to limit disease spread by reducing contact networks and movements.
• The impact of behavioral adaptations on the overall network structure and disease transmission potential remained unknown.

Purpose of the Study:

• To analyze the evolution of cattle contact networks in GB following the implementation of movement restrictions.
• To assess the effectiveness of standstill policies in controlling the spread of infectious diseases in the cattle industry.
• To apply network theory to understand changes in connectivity and disease exposure.

Main Methods:

• Construction of weekly cattle contact networks using Great Britain (GB) cattle movement data.
• Analysis of the giant strong component (GSC) to represent the maximally connected region of the network.
• Tracking the changes in the size of the GSC over time since the introduction of movement restrictions.

Main Results:

• The number of animal holdings (AH) participating in the giant strong component (GSC) has shown a linear increase over time.
• Despite movement restrictions, the core connected component of the cattle network has expanded.
• This expansion indicates a growing number of holdings potentially exposed to disease.

Conclusions:

• Emergent behaviors in the cattle industry have led to an increase in network connectivity.
• The size of the GSC, representing potential disease exposure, has grown, posing a risk to epidemic size.
• Current movement restrictions may not be sufficient to prevent the expansion of infectious disease epidemics in the cattle population.