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Volume 12, Number 7—July 2006

Volume 12, Number 7—July 2006   PDF Version [PDF - 5.58 MB - 139 pages]


  • Emerging Infectious Determinants of Chronic Diseases PDF Version [PDF - 145 KB - 7 pages]
    S. M. O'Connor et al.
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    Infectious agents, often through complex systems, likely determine more chronic diseases than is currently appreciated.

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    Evidence now confirms that noncommunicable chronic diseases can stem from infectious agents. Furthermore, at least 13 of 39 recently described infectious agents induce chronic syndromes. Identifying the relationships can affect health across populations, creating opportunities to reduce the impact of chronic disease by preventing or treating infection. As the concept is progressively accepted, advances in laboratory technology and epidemiology facilitate the detection of noncultivable, novel, and even recognized microbial origins. A spectrum of diverse pathogens and chronic syndromes emerges, with a range of pathways from exposure to chronic illness or disability. Complex systems of changing human behavioral traits superimposed on human, microbial, and environmental factors often determine risk for exposure and chronic outcome. Yet the strength of causal evidence varies widely, and detecting a microbe does not prove causality. Nevertheless, infectious agents likely determine more cancers, immune-mediated syndromes, neurodevelopmental disorders, and other chronic conditions than currently appreciated.

  • Global Public Health Surveillance under New International Health Regulations PDF Version [PDF - 287 KB - 8 pages]
    M. G. Baker and D. P. Fidler
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    IHR 2005 establishes a global surveillance system for public health emergencies of international concern.

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    The new International Health Regulations adopted by the World Health Assembly in May 2005 (IHR 2005) represents a major development in the use of international law for public health purposes. One of the most important aspects of IHR 2005 is the establishment of a global surveillance system for public health emergencies of international concern. This article assesses the surveillance system in IHR 2005 by applying well-established frameworks for evaluating public health surveillance. The assessment shows that IHR 2005 constitutes a major advance in global surveillance from what has prevailed in the past. Effectively implementing the IHR 2005 surveillance objectives requires surmounting technical, resource, governance, legal, and political obstacles. Although IHR 2005 contains some provisions that directly address these obstacles, active support by the World Health Organization and its member states is required to strengthen national and global surveillance capabilities.


  • Neisseria meningitidis Sequence Type and Risk for Death, Iceland PDF Version [PDF - 270 KB - 8 pages]
    M. Gottfreðsson et al.
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    Invasive meningococcal infections are hyperendemic in Iceland, a relatively isolated country in the mid-Atlantic. We performed a nationwide study on all viable meningococcal strains (N = 362) from 1977 to 2004. We analyzed the association of patient's age and sex, meningococcal serogroups, and sequence types (STs) with outcomes. Overall, 59 different STs were identified, 19 of which were unique to Iceland. The most common STs were 32 (24.6%), 11 (19.9%), and 10 (10.2%). The unique ST-3492 ranked fourth (7.7%). The most common serogroups were B (56.4%), C (39.8%), and A (2.2%). Age (p<0.001) and infection with a unique ST (p = 0.011) were independently associated with increased death rates, whereas isolation of meningococci from cerebrospinal fluid only was associated with lower death rates (p = 0.046). This study shows evolutionary trends of meningococcal isolates in a relatively isolated community and highlights an association between unique STs and poor outcome.

  • Tickborne Arbovirus Surveillance in Market Livestock, Nairobi, Kenya PDF Version [PDF - 123 KB - 7 pages]
    R. Sang et al.
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    Numerous tickborne viruses, including Dhori virus and foot-and-mouth disease virus, were isolated.

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    To identify tickborne viruses circulating in Kenya and the surrounding region, we conducted surveillance at abattoirs in Nairobi, Kenya. Species of ticks collected included Rhipicephalus pulchellus (56%), Amblyomma gemma (14%), R. appendiculatus (8%), A. variegatum (6%), and others. A total of 56 virus isolates were obtained, 26 from A. gemma, 17 from R. pulchellus, 6 from A. variegatum, and 7 from other species. Virus isolates included Dugbe virus (DUGV), an unknown virus related to DUGV, Thogoto, Bhanja, Kadam, Dhori, Barur, and foot-and-mouth disease (FMDV) viruses. This is the first report of Dhori virus isolation in East Africa and the first known isolation of FMDV associated with tick collection. Our results demonstrate the potential for tickborne dissemination of endemic and emergent viruses and the relevance of A. gemma in the maintenance of tickborne viruses in this region.

  • Rodent-associated Bartonella Febrile Illness, Southwestern United States PDF Version [PDF - 237 KB - 6 pages]
    J. Iralu et al.
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    Patients showed seroconversion to rodent-associated Bartonella antigens, but not to Bartonella pathogenic for humans.

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    Serum specimens from 114 patients hospitalized with a febrile illness were tested with an indirect immunofluorescence assay (IFA) using Bartonella antigens prepared from 6 species of sigmodontine rodents and 3 known human Bartonella pathogens: B. henselae, B. quintana, and B. elizabethae. Acute- and convalescent-phase serum samples from 5 of these patients showed seroconversion with an IFA titer >512 to rodent-associated Bartonella antigens. The highest titer was against antigen derived from the white-throated woodrat (Neotoma albigula), although this rodent is not necessarily implicated as the source of infection. Three of the 5 who seroconverted showed no cross-reaction to the 3 Bartonella human pathogens. Common clinical characteristics were fever, chills, myalgias, leukopenia, thrombocytopenia, and transaminasemia. Although antibodies to Bartonella are cross-reactive, high-titer seroconversions to rodent-associated Bartonella antigens in adults with common clinical characteristics should stimulate the search for additional Bartonella human pathogens.

  • Migratory Passerine Birds as Reservoirs of Lyme Borreliosis in Europe PDF Version [PDF - 305 KB - 16 pages]
    P. Comstedt et al.
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    Birds host vector ticks and Borrelia species and vary in effectiveness as reservoirs.

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    To define the role of birds as reservoirs and disseminators of Borrelia spirochetes, we characterized tick infestation and reservoir competence of migratory passerine birds in Sweden. A total of 1,120 immature Ixodes ricinus ticks were removed from 13,260 birds and assayed by quantitative polymerase chain reaction (PCR) for Borrelia, followed by DNA sequencing for species and genotype identification. Distributions of ticks on birds were aggregated, presumably because of varying encounters with ticks along migratory routes. Lyme borreliosis spirochetes were detected in 160 (14%) ticks. Borrelia garinii was the most common species in PCR-positive samples and included genotypes associated with human infections. Infestation prevalence with infected ticks was 5 times greater among ground-foraging birds than other bird species, but the 2 groups were equally competent in transmitting Borrelia. Migratory passerine birds host epidemiologically important vector ticks and Borrelia species and vary in effectiveness as reservoirs on the basis of their feeding behavior.

  • Reinfestation Sources for Chagas Disease Vector, Triatoma infestans, Argentina PDF Version [PDF - 182 KB - 7 pages]
    M. C. Cecere et al.
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    Treating all communities within 1,500 m of a target community may reduce reinfestation risk.

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    Reinfestation by Triatoma infestans after insecticide spraying has caused elimination efforts in the dry Chaco region to fail repeatedly. The sources and spatial extent that need to be considered to understand the reinfestation pattern and to plan a comprehensive control program were studied in 2 adjacent rural communities in northwestern Argentina from 1993 to 1997. The effects of external, residual, and primary sources on the reinfestation pattern were evaluated by using geographic information systems, satellite imagery, spatial statistics, and 5-year retrospective data for 1,881 sites. The reinfestation process depended on primary internal sources and on surrounding infested communities. In the dry Chaco, successfully reducing the risk for reinfestation in a community depends on treating all communities and isolated sites within 1,500 m of the target community. In addition, during the surveillance phase, spraying all sites within 500 m of new foci will delay reinfestation.

  • Rickettsia sibirica Isolation from a Patient and Detection in Ticks, Portugal PDF Version [PDF - 139 KB - 6 pages]
    R. de Sousa et al.
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    First R. sibirica–related strain is detected.

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    We report the first isolation of Rickettsia sibirica (strain mongolotimonae) from the blood of a patient and detection by polymerase chain reaction (PCR) of the rickettsia in a Rhipicephalus pusillus tick collected from a dead mongoose (Herpestes ichneumon) in the Alentejo region, Portugal. We describe also the first PCR detection of a new Rickettsia strain that is related to R. sibirica.

  • Orientia tsutsugamushi in Eschars from Scrub Typhus Patients PDF Version [PDF - 144 KB - 4 pages]
    Y. Liu et al.
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    Eschars can be used for genetic characterization of O. tsutsugamushi during the convalescent phase.

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    To verify the value of eschars for the diagnosis of scrub typhus and to characterize genotypes of Orientia tsutsugamushi in patients, we examined eschars and blood specimens of 7 patients from Shandong Province, People's Republic of China, for O. tsutsugamushi by polymerase chain reaction targeting the Sta56 gene. All 7 eschars and acute-phase blood samples were positive, while no specific DNA amplicons were obtained from the 7 convalescent-phase blood samples collected after antimicrobial drug therapy. The findings indicate that patients' eschars can be used for detection and genetic characterization of O. tsutsugamushi during the convalescent phase.

  • Epidemiologic and Molecular Analysis of Human Tularemia, United States, 1964–2004 PDF Version [PDF - 263 KB - 9 pages]
    J. Staples et al.
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    Distinct subpopulations of F. tularensis differ in their clinical manifestations, geographic distribution, and likely modes of transmission.

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    Tularemia in the United States is caused by 2 subspecies of Francisella tularensis, subspecies tularensis (type A) and subspecies holarctica (type B). We compared clinical and demographic features of human tularemia cases from 1964 to 2004 from 39 states in which an isolate was recovered and subtyped. Our data indicate that type A and type B infections differ with respect to affected populations, anatomic site of isolation, and geographic distribution. Molecular subtyping with pulsed-field gel electrophoresis further defined 2 subpopulations of type A (type A-east and type A-west) that differ with respect to geographic distribution, disease outcome, and transmission. Our data suggest that type A-west infections are less severe than either type B or type A-east infections. Through a combined epidemiologic and molecular approach to human cases of tularemia, we provide new insights into the disease for future investigation.




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