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Volume 13, Number 6—June 2007

Volume 13, Number 6—June 2007   PDF Version [PDF - 11.78 MB - 155 pages]


  • Economic Evaluation and Catheter-related Bloodstream Infections PDF Version [PDF - 367 KB - 9 pages]
    K. Halton and N. Graves
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    Catheter-related bloodstream infections are a serious problem. Many interventions reduce risk, and some have been evaluated in cost-effectiveness studies. We review the usefulness and quality of these economic studies. Evidence is incomplete, and data required to inform a coherent policy are missing. The cost-effectiveness studies are characterized by a lack of transparency, short time-horizons, and narrow economic perspectives. Data quality is low for some important model parameters. Authors of future economic evaluations should aim to model the complete policy and not just single interventions. They should be rigorous in developing the structure of the economic model, include all relevant economic outcomes, use a systematic approach for selecting data sources for model parameters, and propagate the effect of uncertainty in model parameters on conclusions. This will inform future data collection and improve our understanding of the economics of preventing these infections.


  • Levels of Abnormal Prion Protein in Deer and Elk with Chronic Wasting Disease PDF Version [PDF - 360 KB - 7 pages]
    B. L. Race et al.
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    Chronic wasting disease (CWD) of deer and elk is a widespread health concern because its potential for cross-species transmission is undetermined. CWD prevalence in wild elk is much lower than its prevalence in wild deer, and whether CWD-infected deer and elk differ in ability to infect other species is unknown. Because lymphoid tissues are important in the pathogenesis of some transmissible spongiform encephalopathies such as sheep scrapie, we investigated whether CWD-affected elk and deer differ in distribution or quantity of disease-associated prion protein (PrPres) in lymphoid tissues. Immunoblot quantification of PrPres from tonsil and retropharyngeal lymph nodes showed much higher levels of PrPres in deer than in elk. This difference correlated with the natural prevalence of CWD in these species and suggested that CWD-infected deer may be more likely than elk to transmit the disease to other cervids and have a greater potential to transmit CWD to noncervids.

  • West Nile Virus Viremia in Eastern Chipmunks (Tamias striatus) Sufficient for Infecting Different Mosquitoes PDF Version [PDF - 334 KB - 7 pages]
    K. B. Platt et al.
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    In eastern chipmunks (Tamias striatus) inoculated intramuscularly with 101.5 to 105.7 PFU of West Nile virus (WNV), serum titers developed sufficient to infect Aedes triseriatus (Say), Ae. vexans (Meigen), and Culex pipiens (L.). Mean titers (95% confidence interval) of 8 chipmunks were 103.9(3.3–4.5), 106.7(6.4–7.0), and 105.8(4.1–7.5) PFU/mL on days 1–3 postinoculation (p.i.) and 105.8 PFU/mL in 1 chipmunk on day 4 p.i. Mean estimated days that WNV titers were >104.8 and >105.6 were 1.7 (1.1–2.3) and 1.4 (1.0–1.6). The longest period of viremia >104.8 PFU/mL was 3–4 days. WNV antigen was detected in the small intestine of 2 chipmunks and the kidneys of 4 chipmunks by immunohistochemistry. WNV also was detected in urine, saliva, and feces of some chipmunks. These data suggest chipmunks might play a role in enzootic WNV cycles and be an amplifying host for mosquitoes that could infect humans.

  • Antimicrobial Drug–Resistant Escherichia coli from Humans and Poultry Products, Minnesota and Wisconsin, 2002–2004 PDF Version [PDF - 418 KB - 9 pages]
    J. R. Johnson et al.
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    The food supply, including poultry products, may transmit antimicrobial drug–resistant Escherichia coli to humans. To assess this hypothesis, 931 geographically and temporally matched E. coli isolates from human volunteers (hospital inpatients and healthy vegetarians) and commercial poultry products (conventionally raised or raised without antimicrobial drugs) were tested by PCR for phylogenetic group (A, B1, B2, D) and 60 virulence genes associated with extraintestinal pathogenic E. coli. Isolates resistant to trimethoprim-sulfamethoxazole, quinolones, and extended-spectrum cephalosporins (n = 331) were compared with drug-susceptible isolates (n = 600) stratified by source. Phylogenetic and virulence markers of drug-susceptible human isolates differed considerably from those of human and poultry isolates. In contrast, drug-resistant human isolates were similar to poultry isolates, and drug-susceptible and drug-resistant poultry isolates were largely indistinguishable. Many drug-resistant human fecal E. coli isolates may originate from poultry, whereas drug-resistant poultry-source E. coli isolates likely originate from susceptible poultry-source precursors.

  • Molecular Characteristics and Epidemiology of Meningococcal Carriage, Burkina Faso, 2003 PDF Version [PDF - 324 KB - 8 pages]
    J. E. Mueller et al.
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    To describe Neisseria meningitidis strains in the African meningitis belt in 2003, we obtained 2,389 oropharyngeal swabs at 5 monthly visits in a representative population sample (age range 4–29 years) in Bobo-Dioulasso, Burkina Faso. A total of 152 carriage isolates were grouped, serotyped, and genotyped. Most isolates were NG:NT:NST sequence type (ST) 192 (63% of all N. meningitidis), followed by W135:2a:P1.5,2 of ST-11 (16%) and NG:15:P1.6 of ST-198 (12%). We also found ST-2881 (W135:NT:P1.5,2), ST-751 (X:NT:P1.5), and ST-4375 (Y:14:P1.5,2) but not serogroups A or C. Estimated average duration of carriage was 30 days (95% confidence interval 24–36 days). In the context of endemic group W135 and meningococcal A disease, we found substantial diversity in strains carried, including all strains currently involved in meningitis in this population, except for serogroup A. These findings show the need for large samples and a longitudinal design for N. meningitidis serogroup A carriage studies.

  • Incidence and Cost of Rotavirus Hospitalizations in Denmark PDF Version [PDF - 218 KB - 5 pages]
    T. Fischer et al.
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    In anticipation of licensure and introduction of rotavirus vaccine into the western market, we used modeling of national hospital registry data to determine the incidence and direct medical costs of annual rotavirus-associated admissions over <11 years in Denmark. Diarrhea-associated hospitalizations coded as nonspecified viral or presumed infectious have demonstrated a marked winter peak similar to that of rotavirus-associated hospitalizations, which suggests that the registered rotavirus-coded admissions are grossly underestimated. We therefore obtained more realistic estimates by 2 different models, which indicated ≈2.4 and ≈2.5 (for children <5 years of age) and ≈4.9 and ≈5.3 (for children <2 years of age) rotavirus-associated admissions per 1,000 children per year, respectively. These admissions amount to associated direct medical costs of US $1.7–1.8 million per year. Using 2 simple models to analyze readily available hospital discharge data resulted in more consistent and reliable estimates.

  • Strategies to Reduce Person-to-Person Transmission during Widespread Escherichia coli O157:H7 Outbreak PDF Version [PDF - 381 KB - 7 pages]
    E. Y. Seto et al.
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    During the Escherichia coli O157:H7 outbreak in 2006 in the United States, the primary strategy to prevent illness was to advise consumers not to eat spinach. No widespread warnings were issued about preventing person-to-person (secondary) transmission. A disease transmission model, fitted to the current data, was used to investigate likely reductions in illnesses that could result from interventions to prevent secondary transmission. The model indicates that exposure to contaminated spinach occurred early in the outbreak and that the secondary illness transmission was similar to that in previous E. coli outbreaks (≈12%). The model also suggests that even a modestly effective strategy to interrupt secondary transmission (prevention of only 2%–3% of secondary illnesses) could result in a reduction of ≈5%–11% of symptomatic cases. This analysis supports the use of widespread public health messages during outbreaks of E. coli O157:H7 with specific advice on how to interrupt secondary transmission.

  • Bovine Spongiform Encephalopathy and Spatial Analysis of the Feed Industry PDF Version [PDF - 347 KB - 6 pages]
    M. Paul et al.
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    In France, despite the ban of meat-and-bone meal (MBM) in cattle feed, bovine spongiform encephalopathy (BSE) was detected in hundreds of cattle born after the ban. To study the role of MBM, animal fat, and dicalcium phosphate on the risk for BSE after the feed ban, we conducted a spatial analysis of the feed industry. We used data from 629 BSE cases as well as on use of each byproduct and market area of the feed factories. We mapped risk for BSE in 951 areas supplied by the same factories and connection with use of byproducts. A disease map of BSE with covariates was built with the hierarchical Bayesian modeling methods, based on Poisson distribution with spatial smoothing. Only use of MBM was spatially linked to risk for BSE, which highlights cross-contamination as the most probable source of infection after the feed ban.

  • Minority-Variant pfcrt K76T Mutations and Chloroquine Resistance, Malawi PDF Version [PDF - 246 KB - 5 pages]
    J. J. Juliano et al.
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    Genotyping of the chloroquine-resistance biomarker pfcrt (Plasmodium falciparum chloroquine resistance transporter gene) suggests that, in the absence of chloroquine pressure, Plasmodium falciparum parasites in Malawi have reverted to chloroquine sensitivity. However, malaria infections in Africa are commonly polyclonal, and standard PCRs cannot detect minority genotypes if present in <20% of the parasites in an individual host. We have developed a multiple site–specific heteroduplex tracking assay (MSS-HTA) that can detect pfcrt 76T mutant parasites consisting of as little as 1% of the parasite population. In clinical samples, no pfcrt 76T was detected in 87 pregnant Malawian women by standard PCR. However, 22 (25%) contained minority-variant resistant genotypes detected by the MSS-HTA. These results were confirmed by subcloning and sequencing. This finding suggests that the chloroquine-resistant genotype remains common in Malawians and that PCR-undetectable drug-resistant genotypes may be present in disease-endemic populations. Surveillance for minority-variant drug-resistant mutations may be useful in making antimalarial drug policy.

  • Human Alveolar Echinococcosis after Fox Population Increase, Switzerland PDF Version [PDF - 358 KB - 5 pages]
    A. Schweiger et al.
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    We analyzed databases spanning 50 years, which included retrospective alveolar echinococcosis (AE) case-finding studies and databases of the 3 major centers for treatment of AE in Switzerland. A total of 494 cases were recorded. Annual incidence of AE per 100,000 population increased from 0.12– 0.15 during 1956–1992 and a mean of 0.10 during 1993–2000 to a mean of 0.26 during 2001–2005. Because the clinical stage of the disease did not change between observation periods, this increase cannot be explained by improved diagnosis. Swiss hunting statistics suggested that the fox population increased 4-fold from 1980 through 1995 and has persisted at these higher levels. Because the period between infection and development of clinical disease is long, the increase in the fox population and high Echinococcus multilocularis prevalence rates in foxes in rural and urban areas may have resulted in an emerging epidemic of AE 10–15 years later.

  • Risk Factors for Imported Fatal Plasmodium falciparum Malaria, France, 1996–2003
    F. Legros et al.
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    Plasmodium falciparum malaria is a serious health hazard for travelers to malaria-endemic areas and is often diagnosed on return to the country of residence. We conducted a retrospective study of imported falciparum malaria among travelers returning to France from malaria-endemic areas from 1996 through 2003. Epidemiologic, clinical, and parasitologic data were collected by a network of 120 laboratories. Factors associated with fatal malaria were identified by logistic regression analysis. During the study period, 21,888 falciparum malaria cases were reported. There were 96 deaths, for a case-fatality rate of 4.4 per 1,000 cases of falciparum malaria. In multivariate analysis, risk factors independently associated with death from imported malaria were older age, European origin, travel to East Africa, and absence of chemoprophylaxis. Fatal imported malaria remains rare and preventable. Pretravel advice and malaria management should take into account these risk factors, particularly for senior travelers.

  • Isolation and Characterization of Novel Human Parechovirus from Clinical Samples PDF Version [PDF - 252 KB - 7 pages]
    K. Watanabe et al.
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    Using Vero cells, we isolated a virus (NII561-2000) from a cerebrospinal fluid specimen of a 1-year-old girl with Reye syndrome. The determined amino acid sequence of the virus indicated that the isolate was a human parechovirus (HPeV), a member of Picornaviridae. Neutralization test showed that the NII561-2000 virus had distinct antigenicity to HPeV-1, HPeV-2, and HPeV-3, and that the sequence was distinct from these types as well as from HPeV-4 and HPeV-5. Thus, we propose the virus (NII561-2000) as the prototype of HPeV-6. We isolated 10 NII561-2000–related viruses, 14 HPeV-1, 16 HPeV-3, and 1 HPeV-4 of 41 HPeVs from various clinical samples collected in Niigata, Japan. Clinical symptoms of the persons infected with the NII561-2000–related viruses were infectious gastroenteritis, rash, upper respiratory tract infection, and paralysis, in addition to Reye syndrome in the 1-year-old girl.



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