N Increased risk of tick-borne diseases with climate and environmental changes.

Climate warming and other environmental changes have contributed to the expansion of the range of several tick species into higher latitudes in North America. As temperatures increase in Canada, the environment becomes more suitable for ticks and the season suitable for tick activity lengthens, so tick-borne diseases are likely to become more common in Canada. In addition to Lyme disease, four other tick-borne diseases (TBDs) have started to emerge and are likely to increase: Anaplasmosis; Babesiosis; Powassan virus; and Borrelia miyamotoi disease. Increased temperature increases the survival and activity period of ticks, increases the range of both reservoir and tick hosts (e.g. mice and deer) and increases the duration of the season when people may be exposed to ticks. Other ticks and TBDs may spread into Canada as the climate changes. The public health strategies to mitigate the impact of all TBDs include surveillance to detect current and emerging TBDs, and public health actions to prevent infections by modifying environmental and social-behavioral risk factors through increasing public awareness. Clinical care strategies include patient education, early detection, laboratory testing, and treatment.

Outbreak of Seoul virus among rats and rat owners - United States and Canada, 2017.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: ​: Seoul virus, a type of hantavirus, is carried by Norway rats. Humans become infected through contact with virus shed in rat urine or droppings, or inhalation of virus particles in dust from contaminated bedding. Infected rats do not develop disease, but humans can experience symptoms ranging from mild influenza-like illness to severe disease with kidney failure and death. Although infections have been previously reported in humans after contact with wild rats, Seoul virus infections had not been reported in pet rats in the United States or Canada. WHAT IS ADDED BY THIS REPORT?: ​: This report describes the first known outbreak of Seoul virus infections in humans from contact with pet rats in the United States and Canada. This investigation identified 31 United States facilities with human and/or rat Seoul virus infections in 11 states, including six that exchanged rats with Canadian ratteries. Seventeen persons had recent infection with Seoul virus, eight became ill, and three were hospitalized and recovered. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: ​: Human hantavirus infections are reportable to state or local health departments in the United States. Clinicians should consider Seoul virus infection in patients with a history of rat contact and compatible symptoms. Pet rat owners and breeders should also be aware of Seoul virus and should practice good hand hygiene and safe rodent handling to prevent infection.

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

Jamestown Canyon and snowshoe hare viruses are two emerging human pathogens associated with cases of neuroinvasive disease in North America. This study aimed to identify environmental and individual risk factors for seropositivity to these arboviruses in humans and pet dogs from Québec, Canada, 2012-2014. In humans, areas with moderate densities of white-tailed deer (Odocoileus virginianus) were associated with higher odds of seropositivity compared with areas with low densities of white-tailed deer (OR 2.50, P = 0.009) and odds of seropositivity were higher in males than in females (OR 2.03, P = 0.016). Among humans reporting more than 10 mosquito bites weekly, the odds of being seropositive were 4.44 times higher (P = 0.004) for people living in hardwood forested areas. Exposure to areas with coniferous forests was identified as the main environmental risk factor for seroconversion in dogs (OR 2.39, P = 0.04). These findings may help target further public health research, diagnostic and surveillance efforts in Canada.

Ixodes scapularis tick distribution and infection rates in Ottawa, Ontario, 2017.

BACKGROUND: The incidence of Lyme disease has increased in many regions of Canada in recent years, including in Ottawa, Ontario. To date there has been limited active tick surveillance in the region. OBJECTIVES: To estimate both the distribution and density of Ixodes scapularis ticks in the city of Ottawa, and the infection rates of ticks with Borrelia burgdorferi (that causes Lyme disease) and other tick-borne pathogens. METHODS: Between June and October 2017, tick surveillance was conducted by drag sampling at 23 sites in Ottawa municipal parks, recreational trails and forests. Blacklegged ticks were tested for B. burgdorferi, Borrelia miyamotoi and Anaplasma phagocytophilum using quantitative polymerase chain reaction protocols. RESULTS: I. scapularis ticks were found in 16 of the 23 sites (70%). Recreational trails, conservation areas/forests and the provincial park within the city of Ottawa had significantly higher tick densities than municipal parks (p<0.01). Of the 194 adult and 26 nymphal I. scapularis tested, prevalence of infection was 29.5% for B. burgdorferi, 0.45% for B. miyamotoi and 0.91% for A. phagocytophilum. CONCLUSION: Almost 30% of I. scapularis ticks tested in suburban and rural areas of the city of Ottawa were infected with B. burgdorferi, known to cause Lyme disease. Other types of infection, known to cause anaplasmosis and tick-borne relapsing fever, were also detected, although were very rare. Conducting active tick surveillance at the local level may help to inform risk assessment and public health actions.

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

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.

Characterizing environmental risk factors for West Nile virus in Quebec, Canada, using clinical data in humans and serology in pet dogs.

The identification of specific environments sustaining emerging arbovirus amplification and transmission to humans is a key component of public health intervention planning. This study aimed at identifying environmental factors associated with West Nile virus (WNV) infections in southern Quebec, Canada, by modelling and jointly interpreting aggregated clinical data in humans and serological data in pet dogs. Environmental risk factors were estimated in humans by negative binomial regression based on a dataset of 191 human WNV clinical cases reported in the study area between 2011 and 2014. Risk factors for infection in dogs were evaluated by logistic and negative binomial models based on a dataset including WNV serological results from 1442 dogs sampled from the same geographical area in 2013. Forested lands were identified as low-risk environments in humans. Agricultural lands represented higher risk environments for dogs. Environments identified as impacting risk in the current study were somewhat different from those identified in other studies conducted in north-eastern USA, which reported higher risk in suburban environments. In the context of the current study, combining human and animal data allowed a more comprehensive and possibly a more accurate view of environmental WNV risk factors to be obtained than by studying aggregated human data alone.

Laboratory diagnostics for Lyme disease.

BACKGROUND: Lyme disease is on the rise in Canada. It is a notifiable disease, and when infection is disseminated, serological testing provides supplemental evidence to confirm a case. OBJECTIVE: To describe the current diagnostic tests for Lyme disease, review the recommended approach to laboratory testing for Lyme disease and identify future research priorities for Lyme disease laboratory diagnostics in Canada. METHODS: A review of the literature was carried out. We then summarized parameters to consider before Lyme disease testing is conducted, described the current best practice to use a two-tiered diagnostic algorithm for the laboratory confirmation of disseminated Lyme disease, and analyzed the advantages and disadvantages of the supplemental tests for Lyme disease. RESULTS: Diagnostic testing is indicated in people who have symptoms of disseminated disease and a history of exposure to vector ticks. To maximize sensitivity and specificity, a two-tiered serological approach is recommended, consisting of an enzyme immunoassay (EIA) screening test followed by confirmation with Western blot (WB) testing. A number of other diagnostic tests are available; however, these are largely for research purposes. CONCLUSION: Two-tiered serology is currently the best approach available to assist doctors when they are making a diagnosis of disseminated Lyme disease. The Public Health Agency of Canada (the Agency) will seek to improve on this approach through standardization of the Lyme disease diagnostics used across laboratories in Canada, evaluation of test performance characteristics of current and new diagnostic platforms and development of a process to secure robust serum panels to assist in the development and evaluation of new diagnostic tests for Lyme disease.

2012: A watershed year for Alzheimer's disease research.

Despite negative topline phase 3 clinical trial results for bapineuzumab and solanezumab in mild to moderate AD, findings from these trials and recent advances suggest renewed optimism for anti-amyloid therapies. Aß immunotherapy has now demonstrated its ability to engage CNS Aß and modify downstream CNS biomarkers in bapineuzumab treated patients, and to show likely cognitive benefits in mild patients treated with solanezumab. The current availability of potent BACE inhibitors provides additional opportunities to test the value of reducing Aß in the clinic. Trial enhancements, such as selecting and enriching for early stage AD, treating participants longer and using more sensitive composite endpoints may further improve our chances of demonstrating clinical efficacy and securing beneficial treatments for patients.

Is there a rationale for including only patients already being treated with acetylcholinesterase inhibitors in a prodromal AD trial?

Prodromal AD clinical trial methodology is advancing rapidly. It is now possible to more accurately identify MCI patients with underlying AD pathology at an earlier stage of the disease through the use of amyloid imaging and CSF biomarkers. Measurement of decline in these early stage clinical trials using continuous clinical and cognitive outcome measures is conceptually more appealing and adds greater efficiency compared to the classical outcome of "conversion" to dementia used in prior MCI clinical trials. Nevertheless, the fact that many prodromal AD patients who are likely to be recruited to these early stage studies are not taking acetylcholinesterase inhibitors at the time of enrollment, but are poised to start taking them over a multi-year period of follow-up, is a potential confound that needs to be addressed.