MHLU - Health Status Resource

Vector-Borne Diseases

Vector-Borne Diseases

Key Findings: 

West Nile Virus

  • Between 2000 and 2011 there were 20 probable and confirmed human cases of West Nile Virus reported in the Middlesex-London area. One case each in 2002, 2005 and 2011 resulted in death.
  • The highest number of annual cases was nine, seen in 2002.
  • All cases of West Nile Virus have only been reported in adults aged 25 and older and nearly 70% of cases were reported in women.

Lyme Disease

  • Between 2000 and 2011, there were 12 cases of Lyme disease reported by residents of Middlesex-London.
  • None of the cases of disease were contracted in the Middlesex-London area. All of the cases were contracted while travelling outside of Middlesex-London in other parts of Ontario and other countries where Lyme disease is endemic. 
  • The number of cases was split evenly between males and females.
  • Compared to West Nile Virus, a higher proportion of the cases were younger with some occurrences in the 15 to 24 year age group. 
Interpretive Notes

The Middlesex-London Health Unit Vector Borne Disease program monitors West Nile Virus (WNV), Lyme Disease (LD) and Eastern Equine Encephalitis (EEE).  Following the nine deaths observed from WNV in 2002, a mosquito surveillance and control program was put in place to lower the risk of WNV infection in residents in 2003. 

While no human cases of EEE have been reported in Canada, there have been 13 positive mosquito pools and 7 equine cases identified in Ontario since 2009. The Vector-Borne Disease program identified many mosquito species within Middlesex-London that are EEE vectors.  

How this Indicator was Calculated: 
Ontario Public Health Standard: 

Population Health Assessment and Surveillance Protocol - Section 1, Subsections b-iii, vi, viii

Rabies Prevention Control - Requirement #4

Infectious Diseases Prevention and Control Standard - Requirement #3

Health Hazard Prevention and Management Standard - Requirement #2