Emerging arboviruses in Quebec, Canada: assessing public health risk by serology in humans, horses and pet dogs

Abstract

Periodic outbreaks of West Nile virus (WNV), Eastern equine encephalitis virus (EEEV) and to a lesser extent, California serogroup viruses (CSGV), have been reported in parts of Canada in the last decade. This study was designed to provide a broad assessment of arboviral activity in Quebec, Canada, by conducting serological surveys for these arboviruses in 196 horses, 1442 dogs and 485 humans. Sera were screened by a competitive enzyme linked immunosorbent assay and positive samples confirmed by plaque reduction neutralisation tests. The percentage of seropositive samples was 83·7%, 16·5%, 7·1% in horses, 18·8%, 0·6%, 0% in humans, 11·7%, 3·1%, 0% in adult dogs and 2·9%, 0·3%, 0% in juvenile dogs for CSGV, WNV and EEEV, respectively. Serological results in horses and dogs appeared to provide a meaningful assessment of risk to public health posed by multiple arboviruses.

Specific detection and differentiation of tick‐borne encephalitis and West Nile virus induced IgG antibodies in humans and horses

“…As a consequence, regions with co‐circulation of WNV and TBEV are increasing in numbers and the differentiation of the two pathogens becomes more and more important. Especially veterinary hosts like horses are critical for the monitoring of virus circulation and they may serve as sentinels for surveillance, control, and risk management programs aiming the early identification of virus circulation before human cases occur (Gossner et al, ; Kolodziejek et al, ; López‐Ruiz et al, ; Rocheleau et al, ). In Austria, seroprevalences among asymptomatic horses of up to 28% have been reported for TBEV (Rushton et al, ), and the first equine WNV cases were confirmed in 2016 (Kolodziejek et al, ).…”

Risk factors associated with seropositivity to California serogroup viruses in humans and pet dogs, Quebec, Canada

“…Sampling was conducted in the context of a broader serological survey for various arboviruses [21]. A total of 1627 dogs were first sampled in 2013 by veterinarians from 89 veterinary clinics distributed through the study area.…”

“…The sera from all dogs (314) living in the same households as these 400 human participants were then tested for CSGV antibodies. In order to achieve a sample size with sufficient statistical power, an additional 88 dogs, randomly selected from our previous study, were also included for serology to reach a total of 402 dogs tested [21]. Only one human per household was then randomly selected for inclusion in the statistical models to avoid clustering.…”

“…From 2012 to 2014, we conducted a serological survey for arboviruses in human and pet dog populations from southern Québec. Previous studies reporting high seroprevalence estimates to various arboviruses in dogs suggested that dogs could represent a sensitive sentinel population for arboviral activity [21]. Although dogs are not clinically affected by CSGV, using them as sentinels may present some advantages for studying environmental risk factors for arboviruses that rarely manifest clinically in humans as it is the case for CSGV.…”

“…Although only a few indigenous human clinical cases of Jamestown Canyon encephalitis have been reported from the province of Québec [22], these results suggested significant and ongoing CSGV transmission in this region. Based on the serological data in Rocheleau et al [21], the current study aimed at assessing the geographical distribution and identifying risk factors for seropositivity to these two arboviruses in humans and pet dogs.…”