Hantavirus Cardiopulmonary Syndrome in Canada.

Hantavirus cardiopulmonary syndrome (HCPS) is a severe respiratory disease caused by Sin Nombre virus in North America (SNV). As of January 1, 2020, SNV has caused 143 laboratory-confirmed cases of HCPS in Canada. We review critical aspects of SNV virus epidemiology and the ecology, biology, and genetics of HCPS in Canada.

Evaluation of commercially available diagnostic tests for the detection of dengue virus NS1 antigen and anti-dengue virus IgM antibody.

Commercially available diagnostic test kits for detection of dengue virus (DENV) non-structural protein 1 (NS1) and anti-DENV IgM were evaluated for their sensitivity and specificity and other performance characteristics by a diagnostic laboratory network developed by World Health Organization (WHO), the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) and the Pediatric Dengue Vaccine Initiative (PDVI). Each network laboratory contributed characterized serum specimens for the panels used in the evaluation. Microplate enzyme-linked immunosorbent assay (ELISA) and rapid diagnostic test (RDT formats) were represented by the kits. Each ELISA was evaluated by 2 laboratories and RDTs were evaluated by at least 3 laboratories. The reference tests for IgM anti-DENV were laboratory developed assays produced by the Armed Forces Research Institute for Medical Science (AFRIMS) and the Centers for Disease Control and Prevention (CDC), and the NS1 reference test was reverse transcriptase polymerase chain reaction (RT-PCR). Results were analyzed to determine sensitivity, specificity, inter-laboratory and inter-reader agreement, lot-to-lot variation and ease-of-use. NS1 ELISA sensitivity was 60-75% and specificity 71-80%; NS1 RDT sensitivity was 38-71% and specificity 76-80%; the IgM anti-DENV RDTs sensitivity was 30-96%, with a specificity of 86-92%, and IgM anti-DENV ELISA sensitivity was 96-98% and specificity 78-91%. NS1 tests were generally more sensitive in specimens from the acute phase of dengue and in primary DENV infection, whereas IgM anti-DENV tests were less sensitive in secondary DENV infections. The reproducibility of the NS1 RDTs ranged from 92-99% and the IgM anti-DENV RDTs from 88-94%.

Management of accidental exposure to Ebola virus in the biosafety level 4 laboratory, Hamburg, Germany.

A needlestick injury occurred during an animal experiment in the biosafety level 4 laboratory in Hamburg, Germany, in March 2009. The syringe contained Zaire ebolavirus (ZEBOV) mixed with Freund's adjuvant. Neither an approved treatment nor a postexposure prophylaxis (PEP) exists for Ebola hemorrhagic fever. Following a risk-benefit assessment, it was recommended the exposed person take an experimental vaccine that had shown PEP efficacy in ZEBOV-infected nonhuman primates (NHPs) [12]. The vaccine, which had not been used previously in humans, was a live-attenuated recombinant vesicular stomatitis virus (recVSV) expressing the glycoprotein of ZEBOV. A single dose of 5 × 10(7) plaque-forming units was injected 48 hours after the accident. The vaccinee developed fever 12 hours later and recVSV viremia was detectable by polymerase chain reaction (PCR) for 2 days. Otherwise, the person remained healthy, and ZEBOV RNA, except for the glycoprotein gene expressed in the vaccine, was never detected in serum and peripheral blood mononuclear cells during the 3-week observation period.

Dengue: a continuing global threat.

Dengue fever and dengue haemorrhagic fever are important arthropod-borne viral diseases. Each year, there are ∼50 million dengue infections and ∼500,000 individuals are hospitalized with dengue haemorrhagic fever, mainly in Southeast Asia, the Pacific and the Americas. Illness is produced by any of the four dengue virus serotypes. A global strategy aimed at increasing the capacity for surveillance and outbreak response, changing behaviours and reducing the disease burden using integrated vector management in conjunction with early and accurate diagnosis has been advocated. Antiviral drugs and vaccines that are currently under development could also make an important contribution to dengue control in the future.

Detection of polyoma and corona viruses in bats of Canada.

Several instances of emerging diseases in humans appear to be caused by the spillover of viruses endemic to bats, either directly or through other animal intermediaries. The objective of this study was to detect, identify and characterize viruses in bats in the province of Manitoba and other regions of Canada. Bats were sampled from three sources: live-trapped Myotis lucifugus from Manitoba, rabies-negative Eptesicus fuscus, M. lucifugus, M. yumanensis, M. septentrionalis, M. californicus, M. evotis, Lasionycteris (L.) noctivagans and Lasiurus (Las.) cinereus, provided by the Centre of Expertise for Rabies of the Canadian Food Inspection Agency (CFIA), and L. noctivagans, Las. cinereus and Las. borealis collected from a wind farm in Manitoba. We attempted to isolate viruses from fresh tissue samples taken from trapped bats in cultured cells of bat, primate, rodent, porcine, ovine and avian origin. We also screened bat tissues by PCR using primers designed to amplify nucleic acids from members of certain families of viruses. We detected RNA of a group 1 coronavirus from M. lucifugus (3 of 31 animals) and DNA from an as-yet undescribed polyomavirus from female M. lucifugus (4 of 31 animals) and M. californicus (pooled tissues from two females).

Evolutional and geographical relationships of Bartonella grahamii isolates from wild rodents by multi-locus sequencing analysis.

To clarify the relationship between Bartonella grahamii strains and both the rodent host species and the geographic location of the rodent habitat, we have investigated 31 B. grahamii strains from ten rodent host species from Asia (Japan and China), North America (Canada and the USA), and Europe (Russia and the UK). On the basis of multi-locus sequencing analysis of 16S rRNA, ftsZ, gltA, groEL, ribC, and rpoB, the strains were classified into two large groups, an Asian group and an American/European group. In addition, the strains examined were clearly clustered according to the geographic locations where the rodents had been captured. In the phylogenetic analysis based on gltA, the Japanese strains were divided into two subgroups: one close to strains from China, and the other related to strains from Far Eastern Russia. Thus, these observations suggest that the B. grahamii strains distributed in Japanese rodents originated from two different geographic regions. In the American/European group, B. grahamii from the North American continent showed an ancestral lineage and strict host specificity; by contrast, European strains showed low host specificity. The phylogenetic analysis and host specificity of B. grahamii raise the possibility that B. grahamii strains originating in the North American continent were distributed to European countries by adapting to various rodent hosts.

Evaluation of commercially available anti-dengue virus immunoglobulin M tests.

Anti-dengue virus immunoglobulin M kits were evaluated. Test sensitivities were 21%-99% and specificities were 77%-98% compared with reference ELISAs. False-positive results were found for patients with malaria or past dengue infections. Three ELISAs showing strong agreement with reference ELISAs will be included in the World Health Organization Bulk Procurement Scheme.

Sin Nombre virus shedding patterns in naturally infected deer mice (Peromyscus maniculatus) in relation to duration of infection.

A 2-year capture-mark-recapture study was conducted in southern Manitoba, Canada, to test for an association between the duration of Sin Nombre virus (SNV) infection in deer mice (Peromyscus maniculatus) and virus shedding. Hantavirus-specific IgG antibodies were detected in 22.2% of captured deer mice, and recently infected deer mice were identified based on the detection of low-avidity IgG antibodies. SNV RNA was detected in blood samples from the majority of seropositive deer mice with no significant difference in the association of SNV RNA between the low- and high-avidity groups (57.8% and 52.1%, respectively). A small subset of seropositive mice (11.6%) had detectable SNV RNA in oropharyngeal fluids (OPF) or urine. A greater proportion of deer mice with low-avidity antibodies had SNV RNA in OPF or urine compared with rodents with high-avidity antibodies (21% versus 6.8%, respectively). This is the first study of naturally infected deer mice to provide evidence that recently infected mice are more likely to shed SNV and thus might represent a greater risk of human infection.

Molecular diagnostics for the detection of human flavivirus infections.

Flaviviruses constitute a genus of viruses that are important etiologic agents of human disease, causing clinical disease ranging from fever to severe manifestations, such as encephalitis and hemorrhagic fever. Serology is presently the most frequently used means of diagnosing flavivirus infections. However, other diagnostic tests may be employed, such as molecular detection, virus isolation and antigen-capture procedures. The applicability of the latter three diagnostic procedures can be expected to vary depending upon the infecting flavivirus, as some flaviviruses, such as dengue, display high and long-term viremias, whereas other flaviviruses produce no, or barely detectable, viremias. Molecular diagnostic techniques have been successfully applied to the diagnosis of flavivirus infections and have the advantage of rapidity, sensitivity and specific identification of the infecting virus. However, it is important to ensure that the right detection tools are employed (for example, appropriate primers and probes to detect the specific virus) and that the laboratory maintains a high proficiency in their testing procedures. Some of the studies that have been employed in the diagnosis of flavivirus infections are reviewed in this article. It seems that there is the potential to develop testing algorithms that successfully employ molecular diagnostics alone or in conjunction with other laboratory techniques for the diagnosis of acute human flavivirus infections.

West Nile Virus infection in humans and horses, Cuba.

A surveillance system to detect West Nile virus (WNV) was established in Cuba in 2002. WNV infection was confirmed by serologic assays in 4 asymptomatic horses and 3 humans with encephalitis in 2003 and 2004. These results are the first reported evidence of WNV activity in Cuba.

Phylogenetic analysis of North American West Nile virus isolates, 2001-2004: evidence for the emergence of a dominant genotype.

The distribution of West Nile virus has expanded in the past 6 years to include the 48 contiguous United States and seven Canadian provinces, as well as Mexico, the Caribbean islands, and Colombia. The suggestion of the emergence of a dominant genetic variant has led to an intensive analysis of isolates made across North America. We have sequenced the pre-membrane and envelope genes of 74 isolates and the complete genomes of 25 isolates in order to determine if a dominant genotype has arisen and to better understand how the virus has evolved as its distribution has expanded. Phylogenetic analyses revealed the continued presence of genetic variants that group in a temporally and geographically dependent manner and provide evidence that a dominant variant has emerged across much of North America. The implications of these findings are discussed as they relate to transmission and spread of the virus in the Western Hemisphere.

West Nile virus. Update for family physicians.

OBJECTIVE: To review the epidemiology and disease manifestations of West Nile virus (WNV) in North America and to describe the current status of therapeutic approaches and vaccines for treating or preventing viral illness. QUALITY OF EVIDENCE: Since 1999, research initiatives investigating the ecology, epidemiology, and biology of WNV have increased substantially. These studies provide a foundation for understanding current activity and predicting future activity and for describing the effect of WNV on human health. MAIN MESSAGE: West Nile virus is transmitted to humans primarily through bites from infected mosquitoes. Most people infected have no symptoms; a few have clinical manifestations ranging from febrile illness to neurologic syndromes and possibly death. Risk of serious disease increases with age, and substantial long-term morbidity has been observed in patients who develop severe neurologic illness. No specific antiviral therapy or vaccine currently exists. CONCLUSION: West Nile virus has established itself in North America and has become an important public health concern. Decreasing risk of virus-associated illness requires seasonal preventive and control measures.

A preliminary study of the patterns of Sin Nombre viral infection and shedding in naturally infected deer mice (Peromyscus maniculatus).

Deer mice (Peromyscus maniculatus) were trapped in southern Manitoba, Canada and tested for evidence of Sin Nombre virus infection. Viral genome was amplified from tissues as well as saliva/oropharyngeal fluid, and urine samples were collected from seropositive animals. Detection of viral RNA in tissue samples and excreta/secreta from mice suggest that differences may exist between naturally infected rodents with respect to viral shedding.

Bartonella seropositivity in children with Henoch-Schonlein purpura.

BACKGROUND: An association between Henoch-Schonlein purpura (HSP) and seropositivity for Bartonella henselae (BH) has been described. The objective of this study was to see if such an association exists in northern Alberta. METHODS: Immunofluorescent antibody testing utilizing an antigen prepared from B. henselae was undertaken on sera from six children with current HSP, 22 children with remote HSP, and 28 controls that were matched for age. Blood from the six children with current HSP was analysed by polymerase chain reaction (PCR) assay with primers derived from the citrate synthase (gltA) gene for the detection of Bartonella DNA. RESULTS: The seropositivity rate for BH was 61% in cases versus 21% in controls (p < 0.03). The PCR assay was negative in all six current cases. CONCLUSION: There is an increased seropositivity rate for BH in children with HSP. However, it is not clear if infection with B. henselae or a related Bartonella species can result in HSP, or if the increased seropositivity is from non-specific or cross-reacting antibodies.

Perspectives on emerging zoonotic disease research and capacity building in Canada.

Zoonoses are fundamental determinants of community health. Preventing, identifying and managing these infections must be a central public health focus. Most current zoonoses research focuses on the interface of the pathogen and the clinically ill person, emphasizing microbial detection, mechanisms of pathogenicity and clinical intervention strategies, rather than examining the causes of emergence, persistence and spread of new zoonoses. There are gaps in the understanding of the animal determinants of emergence and the capacity to train highly qualified individuals; these are major obstacles to preventing new disease threats. The ability to predict the emergence of zoonoses and their resulting public health and societal impacts are hindered when insufficient effort is devoted to understanding zoonotic disease epidemiology, and when zoonoses are not examined in a manner that yields fundamental insight into their origin and spread. Emerging infectious disease research should rest on four pillars: enhanced communications across disciplinary and agency boundaries; the assessment and development of surveillance and disease detection tools; the examination of linkages between animal health determinants of human health outcomes; and finally, cross-disciplinary training and research. A national strategy to predict, prevent and manage emerging diseases must have a prominent and explicit role for veterinary and biological researchers. An integrated health approach would provide decision makers with a firmer foundation from which to build evidence-based disease prevention and control plans that involve complex human/animal/environmental systems, and would serve as the foundation to train and support the new cadre of individuals ultimately needed to maintain and apply research capacity in this area.

A seroprevalence study of west nile virus infection in solid organ transplant recipients.

West Nile virus (WNV) causes severe neurological disease in less than 1% of infections. However, meningoencephalitis may be more common in immunosuppressed transplant patients. In 2002, a WNV outbreak occurred in our region. To determine the spectrum of disease of community acquired WNV infection and assess public health behavior patterns in transplant recipients, we carried out a seroprevalence study. Patients were enrolled from outpatient transplant clinics in October 2002 and sera were screened for WNV. Questionnaires about WNV were provided to patients. Eight hundred sixteen organ transplant patients were enrolled. The seroprevalence of WNV IgM was 2/816 (0.25%; 95% CI 0.03-0.88%). By extrapolation to our entire transplant population of 2360 patients, and using data from hospital-based surveillance, the risk of meningoencephalitis in a transplant patient infected with WNV is estimated to be 40% (95% CI 16-80%). With regards to knowledge and behavior, 56% patients knew of and 47% used at least one protective measure against WNV. Only 33% used insect repellent. The risk of meningoencephalitis in transplant recipients is much higher than in the general population. There is incomplete knowledge and poor rates of compliance amongst patients with regards to WNV prevention.

Perspectives on emerging zoonotic disease research and capacity building in Canada.

Zoonoses are fundamental determinants of community health. Preventing, identifying and managing these infections must be a central public health focus. Most current zoonoses research focuses on the interface of the pathogen and the clinically ill person, emphasizing microbial detection, mechanisms of pathogenicity and clinical intervention strategies, rather than examining the causes of emergence, persistence and spread of new zoonoses. There are gaps in the understanding of the animal determinants of emergence and the capacity to train highly qualified individuals; these are major obstacles to preventing new disease threats. The ability to predict the emergence of zoonoses and their resulting public health and societal impacts are hindered when insufficient effort is devoted to understanding zoonotic disease epidemiology, and when zoonoses are not examined in a manner that yields fundamental insight into their origin and spread.EMERGING INFECTIOUS DISEASE RESEARCH SHOULD REST ON FOUR PILLARS: enhanced communications across disciplinary and agency boundaries; the assessment and development of surveillance and disease detection tools; the examination of linkages between animal health determinants of human health outcomes; and finally, cross-disciplinary training and research. A national strategy to predict, prevent and manage emerging diseases must have a prominent and explicit role for veterinary and biological researchers. An integrated health approach would provide decision makers with a firmer foundation from which to build evidence-based disease prevention and control plans that involve complex human/animal/environmental systems, and would serve as the foundation to train and support the new cadre of individuals ultimately needed to maintain and apply research capacity in this area.