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Volume 14, Number 3—March 2008

Volume 14, Number 3—March 2008   PDF Version [PDF - 5.24 MB - 179 pages]

ICEID logoInternational Conference on
Emerging Infectious Diseases
2008 Slide Sessions and Poster Abstracts


  • Rescinding Community Mitigation Strategies in an Influenza Pandemic PDF Version [PDF - 582 KB - 8 pages]
    V. J. Davey and R. J. Glass
       View Abstract

    Using a networked, agent-based computational model of a stylized community, we evaluated thresholds for rescinding 2 community mitigation strategies after an influenza pandemic. We ended child sequestering or all-community sequestering when illness incidence waned to thresholds of 0, 1, 2, or 3 cases in 7 days in 2 levels of pandemic severity. An unmitigated epidemic or strategy continuation for the epidemic duration served as control scenarios. The 0-case per 7-day rescinding threshold was comparable to the continuation strategy on infection and illness rates but reduced the number of days strategies would be needed by 6% to 32% in mild or severe pandemics. If cases recurred, strategies were resumed at a predefined 10-case trigger, and epidemic recurrence was thwarted. Strategies were most effective when used with high compliance and when combined with stringent rescinding thresholds. The need for strategies implemented for control of an influenza pandemic was reduced, without increasing illness rates.

  • Mycobacterium ulcerans Disease, Peru PDF Version [PDF - 271 KB - 5 pages]
    H. Guerra et al.
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    Eight adult patients (ages 18–58, 5 women) with Buruli ulcer (BU) confirmed by at least 2 diagnostic methods were seen in a 10-year period. Attempts to culture Mycobacterium ulcerans failed. Five patients came from jungle areas, and 3 from the swampy northern coast of Peru. The patients had 1–5 lesions, most of which were on the lower extremities. One patient had 5 clustered gluteal lesions; another patient had 2 lesions on a finger. Three patients were lost to follow-up. All 5 remaining patients had moderate disease. Diverse treatments (antituberculous drugs, World Health Organization [WHO] recommended antimicrobial drug treatment for BU, and for 3 patients, excision surgery) were successful. Only 1 patient (patient 7) received the specific drug treatment recommended by WHO. BU is endemic in Peru, although apparently infrequent. Education of populations and training of health workers are first needed to evaluate and understand the full extent of BU in Peru.

  • Multicenter Cross-Sectional Study of Nontuberculous Mycobacterial Infections among Cystic Fibrosis Patients, Israel PDF Version [PDF - 178 KB - 7 pages]
    I. Levy et al.
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    This 2-year cross-sectional evaluation of nontuberculous mycobacterial (NTM) infections involved all Israeli medical centers that treat cystic fibrosis patients. The study comprised 186 patients whose sputum was analyzed for NTM. The prevalence of NTM isolates was 22.6%, and 6.5% and 10.8% of the patients fulfilled the 1997 and 2007 American Thoracic Society criteria for NTM lung disease, respectively. Mycobacterium simiae (40.5%), M. abscessus (31.0%), and M. avium complex (14.3%) were the most prevalent. Presence of Aspergillus spp. in sputum and the number of sputum specimens processed for mycobacteria were the most significant predictors for isolation of NTM (odds ratio [OR] = 5.14, 95% confidence interval [CI] 1.87–14.11 and OR = 1.47, 95% CI 1.17–1.85, respectively). The incidence of NTM pulmonary infections is increasing among cystic fibrosis patients, reflecting the increase in longevity of such patients as well as environmental exposure to various species of mycobacteria.

  • Mycobacterium xenopi Clinical Relevance and Determinants, the Netherlands PDF Version [PDF - 185 KB - 5 pages]
    J. van Ingen et al.
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    In the Netherlands, isolation of Mycobacterium xenopi is infrequent, and its clinical relevance is often uncertain. To determine clinical relevance and determinants, we retrospectively reviewed medical files of all patients in the Netherlands in whom M. xenopi was isolated from January 1999 through March 2005 by using diagnostic criteria for nontuberculous mycobacterial infection published by the American Thoracic Society. We found 49 patients, mostly white men, with an average age of 60 years and pre-existing pulmonary disease; of these patients, 25 (51%) met the diagnostic criteria. Mycobacterial genotype, based on 16S rRNA gene sequencing, was associated with true infection. Most infections were pulmonary, but pleural and spinal infections (spinal in HIV-infected patients) were also noted. Treatment regimens varied in content and duration; some patients were overtreated and some were undertreated.

  • Epidemiology of Nontuberculous Mycobacteria in Patients without HIV Infection, New York City PDF Version [PDF - 190 KB - 7 pages]
    E. E. Bodle et al.
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    We reviewed medical records of patients without known HIV and with positive cultures for nontuberculous mycobacteria (NTM) isolated during 2000–2003 from 1 large hospital in New York, New York. Overall, 505 patients had positive NTM cultures; 119 (24%) met the criteria for NTM disease. The difference between demographic characteristics of case-patients in our study (66% female, 61% white, and 59% >60 years of age) and those of the base population as determined by regional census data was statistically significant. Estimated incidences for positive cultures, all disease, and respiratory tract disease were 17.7, 2.7, and 2.0 per 100,000 persons, respectively. More patients with rapidly growing mycobacteria (61%), Mycobacterium kansasii (70%), or M. marinum (100%) met criteria for disease than did patients with M. avium complex (MAC) (27%, (p<0.01). NTM disease in patients without HIV is increasing. Laboratory-based surveillance may be useful for detecting non-MAC and non–respiratory tract disease.

  • Exposure to Novel Parainfluenza Virus and Clinical Relevance in 2 Bottlenose Dolphin (Tursiops truncatus) Populations PDF Version [PDF - 342 KB - 9 pages]
    S. Venn-Watson et al.
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    Parainfluenza virus (PIV) is a leading cause of respiratory infections in humans. A novel virus closely related to human and bovine parainfluenza viruses types 3 (HPIV-3 and BPIV-3), named Tursiops truncatus parainfluenza virus type 1 (TtPIV-1), was isolated from a dolphin with respiratory disease. We developed a dolphin-specific ELISA to measure acute- and convalescent-phase PIV antibodies in dolphins during 1999–2006 with hemograms similar to that of the positive control. PIV seroconversion occurred concurrently with an abnormal hemogram in 22 animals, of which 7 (31.8%) had respiratory signs. Seroprevalence surveys were conducted on 114 healthy bottlenose dolphins in Florida and California. When the most conservative interpretation of positive was used, 11.4% of healthy dolphins were antibody positive, 29.8% were negative, and 58.8% were inconclusive. PIV appears to be a common marine mammal virus that may be of human health interest because of the similarity of TtPIV-1 to BPIV-3 and HPIV-3.

  • Hantavirus RNA in Saliva from Patients with Hemorrhagic Fever with Renal Syndrome PDF Version [PDF - 342 KB - 6 pages]
    L. Pettersson et al.
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    Hantaviruses cause 2 zoonotic diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome. Infection is usually initiated after inhalation of virus-contaminated rodent excreta. In addition to the zoonotic infection route, growing evidence suggests person-to-person transmission of Andes virus. For this reason, we studied whether saliva from HFRS patients contained hantavirus. During an outbreak in northern Sweden of nephropathia epidemica (NE), a milder form of hemorrhagic fever with renal syndrome, we collected saliva and plasma from 14 hospitalized NE patients with verified Puumala virus (PUUV) infection. PUUV RNA was detected in saliva from 10 patients (range 1,530–121,323 PUUV RNA copies/mL) by quantitative reverse transcription–PCR. The PUUV S-segment sequences from saliva and plasma of the same patients were identical. Our data show that hantavirus RNA could be detected in human saliva several days after onset of disease symptoms and raise the question whether interhuman transmission of hantavirus may occur through saliva.

  • Increased Mortality Rate Associated with Chikungunya Epidemic, Ahmedabad, India PDF Version [PDF - 177 KB - 4 pages]
    D. Mavalankar et al.
  • Chikungunya Fever in Travelers Returning to Europe from the Indian Ocean Region, 2006 PDF Version [PDF - 249 KB - 7 pages]
    M. Panning et al.
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    Chikungunya fever has spread through several Indian Ocean islands and India, including popular travel destinations. To compare usefulness of diagnostic tests and to understand reasons for the magnitude and severity of an outbreak, we used 3 diagnostic methods to test 720 samples from 680 patients returning to Europe from the Indian Ocean region in 2006. Chikungunya infection was confirmed for 24.4% patients in the first half of the year and for 9.9% in the second half. Reverse transcription–PCR was positive for all samples taken up to day 4 after symptom onset. Immunofluorescence detected immunoglobulin (Ig) M on day 1 and IgG on day 2 for some patients, and in all patients from day 5 onward. Soon after onset of symptoms, patients had IgG and IgM and high viral loads (some >109 copies/mL plasma). These data will help healthcare providers select diagnostic tests for returning travelers.

  • High Rate of Mobilization for blas PDF Version [PDF - 253 KB - 6 pages]
    M. Barlow et al.
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    The blaCTX-Ms have been mobilized to plasmids more frequently than other class A β-lactamases.

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    We constructed a phylogenetic analysis of class A β-lactamases and found that the blaCTX-Ms have been mobilized to plasmids ≈10 times more frequently than other class A β-lactamases. We also found that the blaCTX-Ms are descended from a common ancestor that was incorporated in ancient times into the chromosome of the ancestor of Kluyvera species through horizontal transfer. Considerable sequence divergence has occurred among the descendents of that ancestral gene sequence since that gene was inserted. That divergence has mainly occurred in the presence of purifying selection, which indicates a slow rate of evolution for blaCTX-Ms in the pre–antimicrobial drug era.

  • Integrated Food Chain Surveillance System for Salmonella spp. in Mexico PDF Version [PDF - 385 KB - 7 pages]
    M. B. Zaidi et al.
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    Few developing countries have foodborne pathogen surveillance systems, and none of these integrates data from humans, food, and animals. We describe the implementation of a 4-state, integrated food chain surveillance system (IFCS) for Salmonella spp. in Mexico. Significant findings were 1) high rates of meat contamination (21.3%–36.4%), 2) high rates of ceftriaxone-resistant S. Typhimurium in chicken, ill humans, and swine (77.3%, 66.3%, and 40.4% of S. Typhimurium T isolates, respectively), and 3) the emergence of ciprofloxacin resistance in S. Heidelberg (10.4%) and S. Typhimurium (1.7%) from swine. A strong association between Salmonella spp. contamination in beef and asymptomatic Salmonella spp. infection was only observed in the state with the lowest poverty level (Pearson r = 0.91, p<0.001). Pulsed-field gel electrophoresis analysis of 311 S. Typhimurium isolates showed 14 clusters with 102 human, retail meat, and food-animal isolates with indistinguishable patterns. An IFCS is technically and economically feasible in developing countries and can effectively identify major public health priorities.

  • Genetic Variability of West Nile Virus in US Blood Donors, 2002–2005 PDF Version [PDF - 341 KB - 9 pages]
    A. Grinev et al.
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    West Nile virus (WNV) was detected in the United States in 1999, has reoccurred every summer since, and has become endemic. Transfusion transmission was documented in 2002, and screening of blood donations for WNV began in 2003. We investigated genetic variation of WNV in human isolates obtained from specimens collected from 30 infected blood donors who tested positive for WNV RNA during 2002–2005. Complete genomic sequences of 8 isolates and structural gene sequences from 22 additional isolates were analyzed. We found some genetic diversity in isolates from different geographic regions and genetic divergence from reported sequences from epidemics in 1999–2001. Nucleotide divergence of structural genes showed a small increase from 2002 (0.18%) to 2005 (0.37%), suggesting absence of strong selective pressure and limited genetic evolution of WNV during that period. Nevertheless, WNV has continued to diverge from precursor isolates as geographic distribution of the virus has expanded.

  • Discovering and Differentiating New and Emerging Clonal Populations of Chlamydia trachomatis with a Novel Shotgun Cell Culture Harvest Assay PDF Version [PDF - 410 KB - 9 pages]
    N. Somboonna et al.
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    Chlamydia trachomatis is the leading cause of preventable blindness and bacterial sexually transmitted diseases worldwide. Plaque assays have been used to clonally segregate laboratory-adapted C. trachomatis strains from mixed infections, but no assays have been reported to segregate clones from recent clinical samples. We developed a novel shotgun cell culture harvest assay for this purpose because we found that recent clinical samples do not form plaques. Clones were strain-typed by using outer membrane protein A and 16S rRNA sequences. Surprisingly, ocular trachoma reference strain A/SA-1 contained clones of Chlamydophila abortus. C. abortus primarily infects ruminants and pigs and has never been identified in populations where trachoma is endemic. Three clonal variants of reference strain Ba/Apache-2 were also identified. Our findings reflect the importance of clonal isolation in identifying constituents of mixed infections containing new or emerging strains and of viable clones for research to more fully understand the dynamics of in vivo strain-mixing, evolution, and disease pathogenesis.

  • Molecular Epidemiology of Eastern Equine Encephalitis Virus, New York PDF Version [PDF - 331 KB - 7 pages]
    D. S. Young et al.
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    Southern strains are undergoing amplification, perpetuation, and overwintering in New York.

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    Perpetuation, overwintering, and extinction of eastern equine encephalitis virus (EEEV) in northern foci are poorly understood. We therefore sought to describe the molecular epidemiology of EEEV in New York State during current and past epizootics. To determine whether EEEV overwinters, is periodically reintroduced, or both, we sequenced the E2 and partial NSP3 coding regions of 42 EEEV isolates from New York State and the Eastern Seaboard of the United States. Our phylogenetic analyses indicated that derived subclades tended to contain southern strains that had been isolated before genetically similar northern strains, suggesting southern to northern migration of EEEV along the Eastern Seaboard. Strong clustering among strains isolated during epizootics in New York from 2003–2005, as well as from 1974–1975, demonstrates that EEEV has overwintered in this focus. This study provides molecular evidence for the introduction of southern EEEV strains to New York, followed by local amplification, perpetuation, and overwintering.



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