Seroprevalence of seven zoonotic infections in Nunavik, Quebec (Canada).

In Nunavik, common practices and food habits such as consumption of raw meat and untreated water place the Inuit at risk for contracting zoonotic diseases. The aim of this study was to determine the seroprevalence of seven zoonotic infections among the permanent residents of Nunavik. The study was conducted in the fall 2004 as part of the Nunavik Health Survey. Blood samples from adults aged 18-74 years (n = 917) were collected and analysed for the presence of antibodies against Trichinella spp., Toxocara canis, Echinococcus granulosus, Brucella spp., Coxiella burnetii, Leptospira spp. and Francisella tularensis. Information on sociodemographic characteristics, traditional activities, drinking water supply and nutrition was gathered using english/inuktitut bilingual questionnaires. The chi-squared test was used to evaluate associations between seropositivity and other measured variables. Statistically significant variables were included in a multivariate logistic regression model to control for confounding factors. Estimated seroprevalences were 8.3% for E. granulosus, 3.9% for T. canis, 5.9% for Leptospira spp. and 18.9% for F. tularensis. Seroprevalence was ≤ 1% for Trichinella spiralis, Brucella spp. and C. burnetii. For most infections, seropositivity tended to increase with age. In multivariate analyses, seroprevalence was positively (i.e. directly) associated with age and residence in the Ungava coast area for F. tularensis; age and residence in the Hudson coast area for T. canis; female gender, lower level of schooling and frequent cleaning of water reservoirs for E. granulosus. No risk factor for Leptospira spp. infection was identified. No associations were detected with regards to food habits or environmental exposures. A small but significant portion of the Nunavik population has serologic evidence of exposure to at least one of the pathogenic microorganisms investigated. Further studies are needed to better understand the mechanisms for transmission of zoonotic infections and their potential reservoirs in Nunavik.

Seroprevalence of Toxoplasma gondii among Nunavik Inuit (Canada).

As a result of their intimate contact with the land and their nutritional habits, the Inuit of Nunavik are considered to be at risk from zoonotic infections. To better understand the risk factors for Toxoplasma gondii infection, a serosurvey was conducted in Nunavik, Québec, in September 2004. A representative sample of the Inuit adult population of Nunavik participated in this cross-sectional study (n = 917). Antibodies (IgG) against T. gondii were detected by immunoassay. Information on sociodemographic characteristics, traditional activities, domestic environment and nutrition was gathered by questionnaire and explored as variables explanatory of seropositive results. Associations found to be statistically significant in univariate analyses were assessed by multivariable logistic regression to control for confounding factors. Almost two thirds (59.8%) of the Inuit of Nunavik were found to be seropositive for T. gondii. In multivariate analyses, risk factors for seropositivity were: increasing age, gender (women > men), lower level of education, consumption of potentially contaminated water (determined by an index of risk from waterborne infections), frequent cleaning of water reservoirs, and consumption of seal meat and feathered game. There was some variation in seroprevalence between the Ungava Bay coast (52.3%) and the Hudson Bay coast (65.6%), the two main regions of Nunavik, but this variation was not significant in the multivariable logistic regression model. This cross-sectional study demonstrated high T. gondii seroprevalence in the Inuit population and revealed that age, gender, schooling and community of residence all influence serostatus in this population. Variables related to drinking water and food choices may also influence the risk of infection. These results raise important questions about T. gondii transmission in Nunavik including possible links between terrestrial and marine cycles.

Detection of pathogenic protozoa in the diagnostic laboratory: result reproducibility, specimen pooling, and competency assessment.

Stool microscopy as performed in clinical parasitology laboratories is a complex procedure with subjective interpretation. Quality assurance (QA) programs often emphasize proficiency testing as an assessment tool. We describe a result reproducibility assessment tool, which can form part of a broader QA program, and which is based on the blinded resubmission of selected clinical samples, using concordance between the reports of the initial and resubmitted specimen as an indicator. Specimens preserved in sodium acetate-acetic acid-formalin can be stored for several months for use in such a program. The presence of multiple protozoa in one specimen does not affect concordance. Some dilution of specimens occurs in this process, and this may explain poor concordance when specimens with low protozoal concentrations are resubmitted. Evaluation of this tool in a large parasitology laboratory revealed concordance rates for pathogenic protozoa (Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Dientamoeba fragilis) of about 80%, which may be considered for use as a benchmark value. We also used this tool to demonstrate that when pairs of specimens from one patient are pooled to create a single specimen, concordance between the results of the individual and pooled specimens is high.

The role of gowns in preventing nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA): gown use in MRSA control.

During a 2-year period, a standard isolation protocol for control of methicillin-resistant Staphylococcus aureus was compared with a similar protocol in which gowns were not used but the availability of alcohol-based hand disinfectant was increased. Intervention wards had 0.10 fewer new MRSA transmissions per ward per month, compared with control wards (P was not significant).

Profound T-lymphocytopenia and cryptococcemia in a human immunodeficiency virus-seronegative patient with disseminated tuberculosis.

A 47-year-old human immunodeficiency virus-seronegative West African man who presented in extremis with cachexia, lymphadenopathy, multiple organ dysfunction, and marked T-lymphocytopenia received the diagnosis of disseminated tuberculosis, cryptococcal pneumonia, and cryptococcemia. His subsequent course and our review of the literature suggest that the profound T-lymphocytopenia and ensuing cryptococcal disease were likely attributable to disseminated tuberculosis.

Rubella susceptibility predicts measles susceptibility: implications for postpartum immunization.

Measles and mumps antibody titers were measured in 262 pregnant women who were either positive (n=128) or negative (n=134) for rubella antibodies. Susceptibility to measles and mumps was detected in 4.6% (12/262) and 7.6% (14/184) of the women, respectively. Of the rubella-susceptible group, 8.2% were also measles susceptible, whereas only 0.8% of the rubella-immune women were measles susceptible. Susceptibility to mumps was evenly divided between rubella-susceptible (7.8%) and rubella-immune (7.4%) groups.

Laboratory implementation of the polymerase chain reaction for confirmation of pulmonary tuberculosis.

Decision analysis methods were used to compare four mycobacteriology laboratory strategies with respect to time to confirmation and exclusion of smear-positive and smear-negative cases of pulmonary tuberculosis. Strategies assessed included the following: (i) polymerase chain reaction (PCR) on all respiratory specimens; (ii) PCR on smear-positive specimens and on the broth of vials for other specimens attaining a growth index >10 in a radiometric culture detection system; (iii) PCR on smear-positive specimens only; and (iv) radiometric culture detection, with DNA probe for species identification of vials attaining a growth index >999. Strategies i and ii had predicted average times to confirm cases of 5 and 7.6 days, respectively, and remained within 3 days of each other over a broad range of PCR performance with smear-negative specimens. In contrast, case-confirmation times using strategies iii and iv were 10.4 and 15.3 days, respectively. Only 10% of specimens were processed by PCR in strategy ii. Times to confirm smear-negative cases were comparable for strategies i and ii when PCR sensitivity was <40% with these specimens. Times to exclude pulmonary tuberculosis were similar for all strategies. Given the current suboptimal performance of PCR with smear-negative specimens, strategy ii offers accelerated case confirmation with limited PCR usage.

Fever duration in hospitalized acute pyelonephritis patients.

PURPOSE: To study persistence of fever in treated pyelonephritis with respect to guidelines recommending investigation and modification of therapy after 2 to 3 days of fever. PATIENTS AND METHODS: A retrospective chart review was made of 70 patients hospitalized for febrile pyelonephritis at a community hospital in Canada. RESULTS: Median duration of fever was 34 hours; persistence of fever at 48 and 72 hours was 26% and 13%, respectively. No patients had complications such as intrarenal or perirenal abscess. Prolonged fever was independently associated with increasing baseline creatinine (P = 0.0001), younger age (P = 0.027), and increasing total leukocyte count (P = 0.026). Results of ultrasonography and intravenous urograms were not predictors of fever duration. CONCLUSION: Fever in treated pyelonephritis can take 4 days to resolve, and routine urologic investigation after 2 to 3 days of fever may be unwarranted.

Screening for schistosomiasis, filariasis, and strongyloidiasis among expatriates returning from the tropics.

The clinical utility of eosinophil determinations, stool examinations, and serological studies for detection of parasitic infection was examined in an asymptomatic expatriate population by retrospective chart review. The screened population consisted of 1,605 patients attending a tropical medicine clinic. The sensitivity of eosinophil counts as a screening test for infection with filaria, schistosomes, or Strongyloides stercoralis was 38%, and its positive predictive value was 9%. A cost-efficacy analysis of the use of three diagnostic tests in screening for infection with filaria (n = 23), schistosomes (n = 34), or Strongyloides (n = 7) was performed. The use of stool examination and serological screening together had a sensitivity of 89%, at a total cost similar to that of a conventional strategy involving a stool examination and an eosinophil count, which would have picked up only 61% of our cases. In this population, eosinophil counts contribute little to the diagnostic accuracy obtained with stool examination and serological screening, and the low specificity of eosinophil counts generates high costs.

Strategies for the prevention of neonatal infection with herpes simplex virus: a decision analysis.

Decision analysis was used in the evaluation of nine strategies for the prevention of neonatal infection with herpes simplex virus (HSV). These strategies involve physical examination at labor, weekly screening of pregnant women for shedding of HSV, use of serologic methods specific for HSV type 2, and performance of a rapid diagnostic test at labor. Rates of cesarean delivery and of neonatal infection with HSV were estimated for each strategy, and the estimates were compared with those for a strategy of no intervention. The effects of variations in the sensitivities and specificities of the diagnostic and serologic tests used were analyzed. Given the currently available data and technology, physical examination at labor is the optimal strategy if the primary goal is to minimize the ratio of excess cesarean sections to cases of neonatal HSV infection averted.

Seizure vs. syncope: measuring serum creatine kinase in the emergency department.

OBJECTIVE: To determine the utility of serum creatine kinase measurement for diagnosing generalized tonic-clonic seizures in patients presenting to an emergency department with transient loss of consciousness. DESIGN: Prospective evaluation of a diagnostic parameter. Retrospective data collection with blinded assignment to diagnostic groups. SETTING: University teaching hospital. PATIENTS: Sequential sample of 205 patients with transient loss of consciousness. The study group consisted of 96 patients who had creatine kinase measurements in the emergency department. MEASUREMENTS AND MAIN RESULTS: An investigator blinded to the results of creatine kinase measurements retrospectively classified events into seizure and nonseizure groups on the basis of clinical presentation, prior history, and follow-up investigations. Mean (+/- SE) creatine kinase level was significantly higher in the seizure group (231.1 +/- 34.8 U/L vs. 70.5 +/- 5.6 U/L, p less than 0.001). Elevated creatine kinase had a test specificity of 0.98 (95% CI 0.90-1.00) and a sensitivity of 0.43 (95% CI 0.28-0.59). The discriminating power of creatine kinase elevation was directly related to the time interval between the event and testing (p less than 0.0001). Among samples taken more than three hours after the event, test sensitivity was 0.80 (0.52-1.00) and specificity was 0.94 (0.71-1.00). CONCLUSION: Creatine kinase may be a useful test for evaluating patients with transient loss of consciousness. The test is highly specific for diagnosing generalized seizures in the emergency department. Test sensitivity improves by sampling serum at least three hours after the event.

Antistaphylococcal activity of pentamidine.

Pentamidine isethionate was bacteriostatic against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus sanguis, Micrococcus sp., and Candida albicans. S. aureus was inhibited by concentrations of 16 to 64 micrograms/ml and killed by 64 to greater than or equal to 128 micrograms/ml. Staphylococcal killing was consistently greater in the presence of cations and was unaffected by methicillin resistance.