The epidemiology of human T-cell lymphotropic virus types I and II in Canadian blood donors.

OBJECTIVES: Blood donors in Canada have been tested for Human T-Cell Lymphotropic Virus (HTLV) since 1990. We report the epidemiology, risk factors and lookback/traceback of HTLV-positive donors/recipients. METHODS: The annual HTLV rate was calculated from 1990 to 2010. Residual risk was estimated as the product of incidence and window period. Twenty-nine HTLV-positive donors and 116 matched controls (ratio 1 : 4) were interviewed about risk factors. For HTLV-positive donations, lookback investigations involved identification of all previous donations, and attempting to locate and test recipients. Traceback was initiated when transfusion transmission was queried for HTLV-positive blood recipients. All donors of products that the recipient received were identified, with an attempt to locate and test them. RESULTS: The HTLV rate decreased from 9.35 per 100,000 donations in 1990 to 1.11 in 2010. The residual risk of infection was 1 in 7.6 million donations. In logistic regression birth overseas (OR 18.7), history of sexually transmitted diseases (OR 32.9), sex with unknown background (OR 5.4) and blood transfusion (OR 8.9) were significant predictors. In the lookback study, of 109 HTLV-positive donors, 508 components were transfused, of whom 147 recipients were tested and 18 (12%) were positive. All were transfused prior to the implementation of donor testing. Twenty-three traceback investigations were requested involving 324 transfused untested products,of whom 219 (67.6%) of donors were tested and 13 (6%) were positive for HTLV. CONCLUSIONS: With testing of the blood supply, the risk from HTLV is very low and while most HTLV-positive donors have risk factors, deferrable risk is rare.

Current incidence and residual risk of HIV, HBV and HCV at Canadian Blood Services.

Estimates of the viral residual risk should be updated to reflect current incidence of infection in blood donors. Incidence rates were estimated for allogeneic whole-blood donations made to Canadian Blood Services from 2006 to 2009 based on transmissible disease conversions of repeat donations within a 3-year period. Residual risk was estimated as the incidence multiplied by the window period. The residual risk of HIV was 1 per 8 million donations, HCV 1 per 6·7 million donations and HBV 1 per 1·7 million donations. The residual risk remains low and has decreased for HCV since our previous estimates due to reduced incidence.

Report on the joint IBEPAG/ICCBBA survey on import/export and blood component labelling.

A survey of blood centre organizations was carried out to establish the degree of progress towards the implementation of global standards for coding and labelling blood components. The survey was performed through questionnaires completed by blood organizations. Of nearly 32 million blood donations collected annually by the participants, 43% are identified with ISBT 128 donation numbers and 36% are fully compliant with the ISBT 128 Standard. Planned implementations indicate that 85% of donations will be identified by ISBT 128 donation numbers by 2011.

Zanamivir use during transmission of amantadine-resistant influenza A in a nursing home.

OBJECTIVE: To describe the use of zanamivir during an influenza A outbreak. POPULATION: Residents of a 176-bed long-term-care facility for the elderly in Newmarket, Ontario, Canada, 90% of whom received influenza vaccine in the fall of 1998. OUTBREAK: When respiratory illness due to influenza A was confirmed, infection control measures and amantadine prophylaxis were initiated. Despite these measures, transmission of influenza A continued. INTERVENTION: Zanamivir inhalations, 10 mg daily for prophylaxis and 10 mg twice daily for treatment of influenza. RESULTS: There were 13 definite and 66 probable outbreak-associated cases of influenza A. Twelve (15%) cases developed pneumonia, 7 (9%) were hospitalized, and 2 (2.6%) died. All 12 culture-positive cases yielded influenza A/Sydney/H3N2/05/97-like virus, a 1998/99 vaccine component. The three isolates obtained prior to the initiation of amantadine were amantadine-susceptible; all nine obtained after prophylaxis was instituted were amantadine-resistant. One hundred twenty-nine (92%) of 140 residents who were offered zanamivir accepted it and were able to attempt inhalations. Of these 129, 78% (100) had no difficulty in complying with inhalations. Difficulty with inhalations was associated with decreased functional and mental status. Fifteen (58%) of 26 residents fully dependent in activities of daily living had difficulty compared to 14 (14%) of 100 others (P<.001). Twenty-two (45%) of 49 residents not oriented to person, place, or time had difficulty compared to 7 (10%) of 77 others (P<.001). In the 2 weeks after zanamivir prophylaxis, only 2 new cases of respiratory illness occurred, neither confirmed as influenza. No side effects were identified in 128 zanamivir-treated residents. CONCLUSION: A minority of nursing home residents have difficulty following instructions for zanamivir inhalations. Zanamivir was well tolerated, and its use was temporally associated with termination of an outbreak that amantadine had failed to control.

Etiology of community-acquired pediatric viral diarrhea: a prospective longitudinal study in hospitals, emergency departments, pediatric practices and child care centers during the winter rotavirus outbreak, 1997 to 1998. The Pediatric Rotavirus Epidemiology Study for Immunization Study Group.

OBJECTIVE: To determine the viral etiology of community-acquired diarrhea in children admitted to hospitals and presenting in emergency departments, pediatric practices and child care centers from November 1, 1997, to June 30, 1998. STUDY DESIGN: Children with diarrhea were identified in a prospective multisite cohort study and analyzed according to age, gender and duration of hospitalization. Stools were tested for rotavirus by enzyme immunoassay and for all other enteric viruses by electron microscopy. RESULTS: Of the 2524 children identified with diarrhea, stools of 1386 (55%) were tested by enzyme immunoassay for rotavirus, and of these 1365 (54%) were screened by electron microscopy for all identifiable enteric viruses. Rotavirus was found in 32% (n = 437), adenovirus in 4% (n = 55), torovirus in 3% (n = 44), Norwalk-like viruses in 2% (n = 25) and astrovirus (n = 14) and calicivirus (n = 7) in fewer than 1% of the specimens tested. The proportion of rotavirus was significantly higher in children 12 to 23 months of age (43% of tested stools, n = 159) and 24 to 35 months of age (38% of tested stools, n = 64) (P < 0.001) than in any other age group. Toroviruses were found to approximately the same extent in children > or =36 months of age (6% of tested stools, n = 19) as those <36 months of age. Rotavirus (36% of tested stools, n = 375, P < 0.0005) and torovirus (4% of tested stools, n = 43, P < 0.004) were most often found in hospitalized patients. In contrast Norwalk-like viruses (P < 0.001) and astroviruses (P < 0.01) were more commonly detected in specimens from patients who presented to physicians' offices and who were symptomatic for gastroenteritis in child care centers. CONCLUSION: This study demonstrates that although all known gastroenteritis viruses were diagnosed in symptomatic children, rotavirus was the etiologic agent in most cases of diarrhea managed in the community and in the hospital.

Hospitalization for community-acquired, rotavirus-associated diarrhea: a prospective, longitudinal, population-based study during the seasonal outbreak. The Greater Toronto Area/Peel Region PRESI Study Group. Pediatric Rotavirus Epidemiology Study for Immunization.

OBJECTIVES: To determine the age-specific hospitalization rate for rotavirus-associated diarrhea in Canadian children during the seasonal outbreak, and to characterize children and their households, for assessment of the need for a rotavirus vaccine. DESIGN: Prospective multisite cohort study. SETTINGS AND PARTICIPANTS: Children with an admission diagnosis of diarrhea admitted to 18 hospitals serving 132 study census tracts of a major urban region, from November 1, 1997, through June 30, 1998. Prospective centralized testing of stools was performed; research nurses administered a follow-up questionnaire to parents. MAIN OUTCOME MEASURE: Age-specific diarrhea and rotavirus-associated hospitalization rates. RESULTS: Of 224160 children younger than 5 years, the diarrhea hospitalization rate was 4.8 in 1000 (n = 1086) during the seasonal epidemic. Based on testing of 65% of the hospitalized children, the rotavirus-associated diarrhea hospitalization rate was 1.3 in 1000; the cumulative incidence to 5 years of age was 1 in 160. Rotavirus-associated diarrhea was reported in 37% of the 1001 hospitalized children undergoing testing inside and outside of the census tracts; in children aged 6 to 35 months, this rose to more than 70% during April and May. Ages of children with rotavirus-associated diarrhea were 0 to 2 months (2%), 3 to 5 months (5%), 6 to 23 months (60%), 24 to 35 months (15%), and 36 months or older (19%). Of children aged 0 to 5 and 6 to 11 months, 4 (19%) of 21 and 6 (10%) of 59, respectively, had been born prematurely; 20 (24%) of 83 younger than 1 year were breastfed at the time of illness. Of children younger than 36 months, 77% were cared for in their homes; 13%, in family day care homes; and 8%, in child care centers. The mean (+/- SD) duration of rotavirus hospitalization based on hospital records and parental questioning was 2.4 +/- 1.7 and 3.1 +/- 1.6 days, respectively; it was significantly longer (P < or = .001) in children with an underlying medical condition. One child required intensive care unit hospitalization. Diarrhea occurred concurrently in 74% of household contacts younger than 3 years; 38%, aged 3 to 18 years; and 29%, older than 18 years. Seventy-six percent of parents were married. Household incomes in Canadian dollars in the 81% reporting were less than $20000 in 20%, $20000 to $60000 in 44%, and greater than $60000 in 36%. Ethnicity was reported as 53% white, 15% black, 10% Asian, 12% East Indian, and 11% other. CONCLUSIONS: Based on testing of 65% of children with diarrhea, rotavirus resulted in hospitalization in a minimum of 1 in 160 children by 5 years of age during the seasonal outbreak. Had 100% of young children with diarrhea undergone testing, the extrapolated cumulative incidence of rotavirus-associated diarrhea by 5 years of age may have been 1 in 106.

Rotavirus-associated diarrhea in outpatient settings and child care centers. The Greater Toronto Area/Peel Region PRESI Study Group. Pediatric Rotavirus Epidemiology Study for Immunization.

OBJECTIVES: To determine the prevalence of rotavirus infection in outpatient and child care center (CCC) settings during the seasonal rotavirus outbreak and to describe associated health care utilization. DESIGN: Prospective, multisite cohort study in various ambulatory settings. SETTINGS AND PARTICIPANTS: Participants were children with diarrhea (1) presenting to hospital emergency departments (EDs) and receiving intravenous (IV; n = 8) or oral (n = 1) hydration, (2) seen in pediatric practices (n=4), or (3) attending CCCs (n = 19) between November 1, 1997, and June 30, 1998. Prospective centralized testing of stool samples for rotavirus was performed using enzyme-linked immunosorbent assay and electron microscopy. Study nurses administered follow-up parent questionnaires for rotavirus-positive children. MAIN OUTCOME MEASURE: Prevalence of rotavirus-associated diarrhea. RESULTS: During the 8-month study, rotavirus was identified in 92 children with diarrhea: ED-IV, 20 (44%) of 45; ED-oral, 9 (47%) of 19; pediatric practices, 30 (20%) of 147; and CCCs, 33 (18%) of 186. Of 226 children with diarrhea in pediatric practices, all 5 who progressed to ED-IV hydration or hospitalization were tested, and 3 (60%) were rotavirus positive. Of 211 children in CCCs with diarrhea, 84% who required no health care visits were tested, and of these 10% were positive; of 56 who went on to require a health care visit and 8 who required ED-IV hydration or hospitalization, all were tested, and 27% and 75%, respectively, were rotavirus positive. Among 16 children with rotavirus followed up with ED-IV hydration, 4 (25%) returned and were hospitalized. Maximal health care intervention among 29 children with rotavirus enrolled in pediatric practices included 22 (76%) seeing the pediatrician only, 5 (17%) seeking further care in the ED, 1 (3%) receiving further ED-IV hydration, and 1 (3%) being hospitalized briefly. Maximal health care intervention for 33 children with rotavirus enrolled in CCCs included 13 (39%) who did not visit a physician, 11 (33%) who did, 3 (9%) who sought care in the ED, 1 (3%) who received ED-IV hydration, and 5 (15%) who were hospitalized. In CCCs, rates of diarrhea per 100 child-months of observation were as follows: ages 0 to 23 months, 6.6 episodes; ages 24 to 35 months, 1.9 episodes; and 3 years and older, 0.07 episodes; rates of rotavirus-associated diarrhea were as follows: ages 0 to 23 months, 1.1 episodes (28 of 2547); ages 24 to 35 months, 0.23 episodes (5 of 2185); and 3 years and older, 0 episodes (0 of 4124). CONCLUSION: Across a variety of outpatient and CCC settings, rotavirus is an important cause of diarrhea and a major cause of health care utilization.

Performance of indirect immunoglobulin M (IgM) serology tests and IgM capture assays for laboratory diagnosis of measles.

As progress is made toward elimination of measles, the laboratory confirmation of measles becomes increasingly important. However, both false-positive and false-negative results can occur with the routinely used indirect measles immunoglobulin M (IgM) serology tests. The measles IgM capture assay is considered to be more specific, and therefore, its use is indicated for confirmatory testing, but its relative performance has not been fully assessed. Four commercial indirect measles IgM serology test kits (the Behring, Clark, Gull, and PanBio assays) and a commercial IgM capture assay (the Light Diagnostics assay) were evaluated for their abilities to detect measles virus-specific IgM antibody with a total of 308 serum samples from patients involved in a measles outbreak and with confirmed cases of measles and 454 samples from subjects without measles. The Centers for Disease Control and Prevention (CDC) IgM capture assay was also used in a part of the evaluation. Among the indirect assays, the overall sensitivities ranged from 82.8% (Clark assay) to 88.6% (Behring assay) and specificity ranged from 86.6% (PanBio assay) to 99.6% (Gull assay). These rates were 92.2 and 86. 6%, respectively, for the Light Diagnostics capture assay and 87.0 and 94.8%, respectively, for the CDC capture assay. While the Light Diagnostics capture assay had the best detection rate (80%) with the acute-phase samples compared with those for the rest of the tests (CDC capture assay, 77%; Behring assay, 70%; Gull assay, 69%; PanBio assay, 58%; and Clark assay, 57%), all tests showed a significantly improved sensitivity in the range of 92% (Clark and PanBio assays) to 97% (Light Diagnostics and CDC capture assays) with the convalescent-phase samples, as expected. The best seropositivity rates (in the range of 92 to 100%) were observed with samples collected 6 to 14 days after the onset of symptoms. The Gull assay showed the highest positive predictive value (99.6%), followed by the Behring assay (97.8%) and the CDC capture assay (96.1%). Overall, the Gull and Behring assays were found to be as good as or better than the capture assays. In conclusion, laboratory diagnosis of measles based on IgM serology varies depending on the timing of specimen collection and the test used, and the case for the use of the IgM capture assay as the confirmatory test appears to be uncertain.

Measles inclusion-body encephalitis caused by the vaccine strain of measles virus.

We report a case of measles inclusion-body encephalitis (MIBE) occurring in an apparently healthy 21-month-old boy 8.5 months after measles-mumps-rubella vaccination. He had no prior evidence of immune deficiency and no history of measles exposure or clinical disease. During hospitalization, a primary immunodeficiency characterized by a profoundly depressed CD8 cell count and dysgammaglobulinemia was demonstrated. A brain biopsy revealed histopathologic features consistent with MIBE, and measles antigens were detected by immunohistochemical staining. Electron microscopy revealed inclusions characteristic of paramyxovirus nucleocapsids within neurons, oligodendroglia, and astrocytes. The presence of measles virus in the brain tissue was confirmed by reverse transcription polymerase chain reaction. The nucleotide sequence in the nucleoprotein and fusion gene regions was identical to that of the Moraten and Schwarz vaccine strains; the fusion gene differed from known genotype A wild-type viruses.

Toronto street youth and HIV/AIDS: prevalence, demographics, and risks.

PURPOSE: The purposes of this study were: (a) to identify human immunodeficiency virus (HIV) prevalence in Toronto street youth through paired blood and saliva specimens; (b) to identify the HIV risk and prevention behaviors of street involved youth; and (c) to identify demographic or other factors that may contribute to the risk of street youth becoming infected with HIV/acquired immunodeficiency syndrome (AIDS) in the future. METHODS: This was a cross-sectional convenience study of street-involved youth aged 14-25 years. The youth participated in interviews to identify HIV-related knowledge and personal risk and preventive behaviors. Following interviews, they were asked to provide a saliva sample, blood spot, or both. They could refuse one or both samples without jeopardizing their involvement or receiving an honorarium. Two males were the only participants who declined to provide a sample. RESULTS: Fifteen of 695 (2.2%) youth tested positive for HIV infection. All were male, ranging in age from 18 to 25 years. Same and opposite sex, intravenous (IV) drug use, prostitution, and incarceration were risk factors associated with positive HIV test results. The rate of HIV infection was seven times greater for the group 20 years of age and older (20-25) compared to the younger group aged 14-9 years. The proportion testing positive for HIV from small cities, towns, and rural communities in Ontario was 40%; yet, they represented 21% of the study population. Most (57%) youth had been on their own for no more than 3 years and had moved frequently. Nearly two thirds (60%) had stayed in hostels or homeless shelters in the previous 6 months. CONCLUSION: Street youth in Canada are at high risk of HIV infection with their risk increasing with age. Unprotected (same and opposite) sex, IV drug use, prostitution and incarceration were linked to their HIV infections. The high level of mobility identified by street youth challenges governments, communities, and public health officials to develop appropriate prevention strategies and to carefully monitor the spread of HIV infection in this vulnerable population.