Toxoplasma gondii DNA in Tissues of Anadromous Arctic Charr, Salvelinus alpinus, Collected From Nunavik, Québec, Canada.

Background: Toxoplasma gondii is a very common zoonotic parasite in humans and animals worldwide. Human seroprevalence is high in some regions of Canada's North and is thought to be associated with the consumption of traditionally prepared country foods, such as caribou, walrus, ringed seal and beluga. While numerous studies have reported on the prevalence of T.

Foodborne protozoan parasites in fresh mussels and oysters purchased at retail in Canada.

Studies worldwide have reported the presence of protozoan parasites in a variety of commercial bivalve shellfish. The uptake of these parasites by shellfish occurs during filter feeding in faecally-contaminated waters. The objective of the present study was to determine the prevalence of Giardia, Cryptosporidium and Toxoplasma in fresh, live shellfish purchased in three Canadian provinces as part of the retail surveillance activities led by FoodNet Canada (Public Health Agency of Canada).

A cloth-based hybridization array system for rapid detection of the food- and waterborne protozoan parasites , spp. and .

Protozoan parasites in food or water samples are generally detected using microscopy or PCR followed by Sanger sequencing. However, microscopy is subjective, requires a high degree of expertise and has limited sensitivity, while DNA sequencing requires expensive and specialized equipment and facilities. This study describes a cloth-based hybridization array system (CHAS) that is an alternative to Sanger sequencing to confirm PCR-positive samples.

, sp. and like parasites in seals from northern and eastern Canada: potential risk to consumers.

Zoonotic parasites of seals that are harvested for food may pose a health risk when seal meat or organ tissues of infected animals are eaten raw or undercooked. In this study, 124 tissue samples from 81 seals, comprising four species, were collected from northern and eastern Canada. Tissues from 23 ringed seals (), 8 hooded seals (), 21 harp seals (), and 29 grey seals () were tested for parasites of the Sarcocystidae family including , spp.

Baseline clinical HIV genotypes are a valid measure of transmitted drug resistance within the treatment-naive population.

Objective: To examine whether baseline clinical genotypes are equivalent to diagnostic serum genotypes for surveillance of HIV transmitted drug resistance (TDR).

Design: Current HIV TDR surveillance in Canada is conducted through genotyping remnant diagnostic sera from new HIV diagnoses. As part of routine care, baseline genotyping is now conducted on all newly diagnosed HIV infections, with TDR data being generated a second time on the same patients.

Local phylogenetic analysis identifies distinct trends in transmitted HIV drug resistance: implications for public health interventions.

Background: HIV transmitted drug resistance (TDR) surveillance is usually conducted by sampling from a large population. However, overall TDR prevalence results may be inaccurate for many individual clinical setting. We analyzed HIV genotypes at a tertiary care setting in Ottawa, Ontario in order to evaluate local TDR patterns among sub-populations.

Evolution of primary HIV drug resistance in a subtype C dominated epidemic in Mozambique.

Objective: In Mozambique, highly active antiretroviral treatment (HAART) was introduced in 2004 followed by decentralization and expansion, resulting in a more than 20-fold increase in coverage by 2009. Implementation of HIV drug resistance threshold surveys (HIVDR-TS) is crucial in order to monitor the emergence of transmitted viral resistance, and to produce evidence-based recommendations to support antiretroviral (ARV) policy in Mozambique.

Methods: World Health Organization (WHO) methodology was used to evaluate transmitted drug resistance (TDR) in newly diagnosed HIV-1 infected pregnant women attending ante-natal clinics in Maputo and Beira to non-nucleoside reverse transcriptase inhibitors (NNRTI), nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI).

Low abundance drug resistance variants in transmitted HIV drug resistance surveillance specimens identified using tagged pooled pyrosequencing.

HIV drug resistance (DR) testing using Sanger sequencing (SS) is limited by the inability of the method to identify low abundance drug resistance variants. The application of tagged pooled pyrosequencing (TPP) for HIV DR surveillance is described and the results compared with SS. HIV(+) serum specimens were genotyped using both SS and TPP.

Genetic diversity as a marker for timing infection in HIV-infected patients: evaluation of a 6-month window and comparison with BED.

Background: It has been reported that the increase in human immunodeficiency virus (HIV) sequence diversity in drug resistance surveillance specimens may be used to classify the duration of HIV infection as <1 or >1 year. We describe a mixed base classifier (MBC) optimized to categorize the duration of subtype B infections as <6 or >6 months on the basis of sequences for drug resistance surveillance specimens and compared MBC findings with those of serologic methods.

Methods: The behavior of the MBC was examined across a range of thresholds for calling mixed bases.

Adaptive evolution of HIV at HLA epitopes is associated with ethnicity in Canada.

Host immune selection pressure influences the development of mutations that allow for HIV escape. Mutation patterns induced in HIV by the human leukocyte antigen (HLA) are HLA-allele specific. As ethnic groups have distinct and characteristic HLA allele frequencies, we can expect divergent viral evolution within ethnicities.

No evidence of cross-species transmission of mouse retroviruses to animal workers exposed to mice.

Background: Although recent data have brought into question the association between xenotropic murine leukemia virus-related virus (XMRV) and chronic fatigue syndrome, one group has reported evidence of human infection with distinct polytropic murine leukemia viruses (MLVs). Occult retroviral infection among humans poses a significant public health risk should it be introduced into the blood supply. To explore the possibility of cross-species transmission of MLVs to humans, we sought molecular and serologic evidence of XRMV/MLV infection among a cohort of animal workers highly exposed to mice.

Next-generation sequencing of dried blood spot specimens: a novel approach to HIV drug-resistance surveillance.

Background: HIV drug-resistance (DR) surveillance in resource-limited settings can be performed using dried blood spots (DBS) because of ease of collection, transportation and storage. Analysis of pooled specimens on next-generation sequencing (NGS)-based platforms, such as the 454 pyrosequencing, is an efficient sequencing method for determining HIV DR rates. In this study, we conducted HIV DR surveillance on DBS using NGS and identified minority variants in individual patients.

Towards targeted screening for acute HIV infections in British Columbia.

Background: Our objective was to describe the characteristics of acute and established HIV infections diagnosed in the Canadian province of British Columbia. Province-wide HIV testing and surveillance data were analyzed to inform recommendations for targeted use of screening algorithms to detect acute HIV infections.

Methods: Acute HIV infection was defined as a confirmed reactive HIV p24 antigen test (or HIV nucleic acid test), a non-reactive or reactive HIV EIA screening test and a non-reactive or indeterminate Western Blot.

Longitudinal phylogenetic surveillance identifies distinct patterns of cluster dynamics.

Objective: Through the application of simple, accessible, molecular epidemiology tools, we aimed to resolve the phylogenetic relationships that best predicted patterns of cluster growth using longitudinal population level drug resistance genotype data.

Methods: Analysis was performed on 971 specimens from drug naïve, first time HIV positive subjects collected in British Columbia between 2002 and 2005. A 1240bp fragment of the pol gene was amplified and sequenced with relationships among subtype B sequences inferred using Neighbour-Joining analysis.

HIV drug resistance surveillance using pooled pyrosequencing.

Background: Surveillance for HIV transmitted drug resistance (TDR) is performed using HIV genotype results from individual specimens. Pyrosequencing, through its massive parallel sequencing ability, can analyze large numbers of specimens simultaneously. Instead of using pyrosequencing conventionally, to sequence a population of viruses within an individual, we interrogated a single combined pool of surveillance specimens to demonstrate that it is possible to determine TDR rates in HIV protease from a population of individuals.

No evidence of PERV infection in healthcare workers exposed to transgenic porcine liver extracorporeal support.

Background: Clinical xenotransplantation holds great promise by providing one solution to the shortage of human organs for transplantation, while also posing a potential public health threat by facilitating transmission of infectious disease from source animals to humans. One potential vector for infectious disease transmission is healthcare workers (HCW) who are involved in administering xenotransplantation procedures.

Methods: In this study, we studied 49 healthcare workers involved in the care of two subjects who participated in a study of porcine liver perfusion as treatment of fulminant hepatic failure.

Characterization of blood-borne transmission of simian foamy virus.

Background: Simian foamy virus (SFV) is an endemic, nonhuman primate (NHP) retrovirus that is transmitted to individuals who work with or hunt NHPs. The cross-species transmission of simian retroviruses is believed to be the etiology of human immunodeficiency virus and human T-lymphotropic virus infections in humans. Although SFV is not pathogenic in the native host, the shared ancestry with other simian retroviruses has brought into question the potential for acquired pathogenicity after cross-species transmission.