Distribution of West Nile virus cases in horses reveals different spatiotemporal patterns in eastern and western Canada.

The research article focuses on the spatiotemporal patterns of West Nile virus in horses from 2003 to 2020 in Canada. The key findings include varying patterns in eastern and western regions of Canada and the need for targeted prevention and control efforts based on these spatiotemporal patterns.

Research Methodology

• This study used data from the Canadian Food Inspection Agency, consisting of 848 symptomatic and laboratory-confirmed West Nile virus (WNV) cases in horses reported between 2003 and 2020.
• For analysis, Canada was divided into eastern and western regions. Each case’s location and the date of notification were tracked.
• Triennial maps (maps developed every three years) were created to describe the spatiotemporal distribution and expansion of reported cases.
• A simple linear regression was used to investigate the association between the year and latitude of the cases.
• Space-time clusters were identified using a permutation scan test.

Research Findings

• Most of the western region displayed an extended distribution of WNV cases from 2003 to 2005.
• In the western region, there was a high recurrence of cases at the census division level.
• In the eastern region, the expansion of cases was gradual, with newly infected census divisions mostly contiguous to the previous ones.
• The team found no association between year and latitude of cases, indicating no spatial correlation of virus spread with the geographical distribution.
• The study revealed six specific spatiotemporal clusters of high infection rates.

Conclusions

• The research confirmed that WNV has become endemic in certain areas in both eastern and western parts of Canada, with variations in local risk over time.
• The study suggests directing prevention and control efforts to previously infected areas based on the spatiotemporal regional distribution patterns to manage the disease effectively.
• The research also cautions anticipatory measures against the incursion of WNV into new areas.
• These findings could facilitate enhancing monitoring and preventive measures against WNV infections in creating an efficient integrated surveillance system.