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Volume 12, Number 9—September 2006

Volume 12, Number 9—September 2006   PDF Version [PDF - 6.12 MB - 171 pages]

Perspective

  • Nosocomial Tuberculosis in India PDF Version [PDF - 276 KB - 8 pages]
    M. Pai et al.
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    India is well positioned to address the problem of nosocomial tuberculosis transmission.

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    Most high-income countries implement tuberculosis (TB) infection control programs to reduce the risk for nosocomial transmission. However, such control programs are not routinely implemented in India, the country that accounts for the largest number of TB cases in the world. Despite the high prevalence of TB in India and the expected high probability of nosocomial transmission, little is known about nosocomial and occupational TB there. The few available studies suggest that nosocomial TB may be a problem. We review the available data on this topic, describe factors that may facilitate nosocomial transmission in Indian healthcare settings, and consider the feasibility and applicability of various recommended infection control interventions in these settings. Finally, we outline the critical information needed to effectively address the problem of nosocomial transmission of TB in India.

Synopses

  • Control of Avian Influenza in Poultry PDF Version [PDF - 169 KB - 6 pages]
    I. Capua and S. Marangon
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    Vaccines that enable detection of field exposure to any AI would be ideal.

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    Avian influenza, listed by the World Organization for Animal Health (OIE), has become a disease of great importance for animal and human health. Several aspects of the disease lack scientific information, which has hampered the management of some recent crises. Millions of animals have died, and concern is growing over the loss of human lives and management of the pandemic potential. On the basis of data generated in recent outbreaks and in light of new OIE regulations and maintenance of animal welfare, we review the available control methods for avian influenza infections in poultry, from stamping out to prevention through emergency and prophylactic vaccination.

Research

  • Risk Factors for Buruli Ulcer, Benin PDF Version [PDF - 140 KB - 7 pages]
    M. Debacker et al.
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    Disease was associated with age, place of residence, and water sources in all age groups.

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    We identified risk factors for Buruli ulcer (BU) in Benin in an unmatched case-control study at the Centre Sanitaire et Nutritionnel Gbemoten in southern Benin. A total of 2,399 persons admitted from 1997 through 2003 and 1,444 unmatched patients with other conditions in 2002 were recruited. Adjusted odds ratios were determined for age, sex, place of residence, Mycobacterium bovis BCG vaccination at birth, type of water for domestic use, and occupation. Children <15 years of age and adults >49 years of age had a higher risk for BU. Use of unprotected water from swamps was associated with increased risk for BU; this association was strongest in adults >49 years of age. Sex was not a risk factor for BU. Our data showed that BU was mainly associated with age, place of residence, and water sources in all age groups. Risk for BU was higher in BCG-vaccinated patients >5 years of age.

  • Histologic Features and Immunodetection of African Tick-bite Fever Eschar PDF Version [PDF - 438 KB - 6 pages]
    H. Lepidi et al.
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    Immunohistochemical detection of rickettsial antigens may be useful in diagnosis.

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    African tick-bite fever (ATBF) is a rickettsiosis caused by Rickettsia africae. We describe histologic features and immunodetection of R. africae in cutaneous inoculation eschars from 8 patients with ATBF, which was diagnosed by culture or association of positive PCR detection and positive serologic results. We used quantitative image analysis to compare the pattern of inflammation of these eschars with those from Mediterranean spotted fever. We evaluated the diagnostic value of immunohistochemical techniques by using a monoclonal antibody to R. africae. ATBF eschars were histologically characterized by inflammation of vessels composed mainly of significantly more polymorphonuclear leukocytes than are found in cases of Mediterranean spotted fever (p<0.05). Small amounts R. africae antigens were demonstrated by immunohistochemical examination in 6 of 8 patients with ATBF. Neutrophils in ATBF are a notable component of the host reaction, perhaps because ATBF is a milder disease than the other rickettsioses. Immunohistochemical detection of rickettsial antigens may be useful in diagnosing ATBF.

  • Lymph Node Biopsy Specimens and Diagnosis of Cat-scratch Disease PDF Version [PDF - 126 KB - 7 pages]
    J. Rolain et al.
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    Histologic analysis of lymph node biopsy specimens may verify diagnosis of this disease.

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    We report microbiologic analysis of 786 lymph node biopsy specimens from patients with suspected cat-scratch disease (CSD). The specimens were examined by standard, cell culture, and molecular methods. Infectious agents were found in samples from 391 (49.7%) of 786 patients. The most commonly identified infectious agent was Bartonella henselae (245 patients, 31.2%), the agent of CSD. Mycobacteriosis was diagnosed in 54 patients (6.9%) by culture and retrospectively confirmed by using a specific real-time PCR assay. Neoplasm was diagnosed in 181 specimens suitable for histologic analysis (26.0%) from 47 patients. Moreover, 13 patients with confirmed Bartonella infections had concurrent mycobacteriosis (10 cases) or neoplasm (3 cases). A diagnosis of CSD does not eliminate a diagnosis of mycobacteriosis or neoplasm. Histologic analysis of lymph node biopsy specimens should be routinely performed because some patients might have a concurrent malignant disease or mycobacteriosis.

  • Periurban Trypanosoma cruzi–infected Triatoma infestans, Arequipa, Peru PDF Version [PDF - 344 KB - 8 pages]
    M. Z. Levy et al.
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    Simple interventions may facilitate vector control and prevent periurban transmission of Chagas disease.

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    In Arequipa, Peru, vectorborne transmission of Chagas disease by Triatoma infestans has become an urban problem. We conducted an entomologic survey in a periurban community of Arequipa to identify risk factors for triatomine infestation and determinants of vector population densities. Of 374 households surveyed, triatomines were collected from 194 (52%), and Trypanosoma cruzi–carrying triatomines were collected from 72 (19.3%). Guinea pig pens were more likely than other animal enclosures to be infested and harbored 2.38× as many triatomines. Stacked brick and adobe enclosures were more likely to have triatomines, while wire mesh enclosures were protected against infestation. In human dwellings, only fully stuccoed rooms were protected against infestation. Spatially, households with triatomines were scattered, while households with T. cruzi–infected triatomines were clustered. Keeping small animals in wire mesh cages could facilitate control of T. infestans in this densely populated urban environment.

  • Genomic Signatures of Human versus Avian Influenza A Viruses PDF Version [PDF - 345 KB - 8 pages]
    G. Chen et al.
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    Fifty-two species-associated amino acid residues were found between human and avian influenza viruses.

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    Position-specific entropy profiles created from scanning 306 human and 95 avian influenza A viral genomes showed that 228 of 4,591 amino acid residues yielded significant differences between these 2 viruses. We subsequently used 15,785 protein sequences from the National Center for Biotechnology Information (NCBI) to assess the robustness of these signatures and obtained 52 "species-associated" positions. Specific mutations on those points may enable an avian influenza virus to become a human virus. Many of these signatures are found in NP, PA, and PB2 genes (viral ribonucleoproteins [RNPs]) and are mostly located in the functional domains related to RNP-RNP interactions that are important for viral replication. Upon inspecting 21 human-isolated avian influenza viral genomes from NCBI, we found 19 that exhibited >1 species-associated residue changes; 7 of them contained >2 substitutions. Histograms based on pairwise sequence comparison showed that NP disjointed most between human and avian influenza viruses, followed by PA and PB2.

  • Changing Pattern of Human Listeriosis, England and Wales, 2001–2004 PDF Version [PDF - 209 KB - 6 pages]
    I. A. Gillespie et al.
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    Disease has reemerged, mainly in patients ≥60 years of age with bacteremia.

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    Microbiologic and epidemiologic data on 1,933 cases of human listeriosis reported in England and Wales from 1990 to 2004 were reviewed. A substantial increase in incidence occurred from 2001 to 2004. Ten clusters (60 cases), likely to represent common-source outbreaks, were detected. However, these clusters did not account for the upsurge in incidence, which occurred sporadically, predominantly in patients >60 years of age with bacteremia and which was independent of sex; regional, seasonal, ethnic, or socioeconomic differences; underlying conditions; or Listeria monocytogenes subtype. The reasons for the increase are not known, but since multiple L. monocytogenes strains were responsible, this upsurge is unlikely to be due to a common-source outbreak. In the absence of risk factors for listeriosis in this emerging at-risk sector of the population, dietary advice on avoiding high-risk foods should be provided routinely to the elderly and immunocompromised, not just to pregnant women.

  • Predominance of Ancestral Lineages of Mycobacterium tuberculosis in India PDF Version [PDF - 211 KB - 8 pages]
    M. C. Gutierrez et al.
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    Molecular epidemiologic findings suggest an ancient focus of TB.

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    Although India has the highest prevalence of tuberculosis (TB) worldwide, the genetic diversity of Mycobacterium tuberculosis in India is largely unknown. A collection of 91 isolates originating from 12 different regions spread across the country were analyzed by genotyping using 21 loci with variable-number tandem repeats (VNTRs), by spoligotyping, by principal genetic grouping (PGG), and by deletion analysis of M. tuberculosis–specific deletion region 1. The isolates showed highly diverse VNTR genotypes. Nevertheless, highly congruent groupings identified by using the 4 independent sets of markers permitted a clear definition of 3 prevalent PGG1 lineages, which corresponded to the "ancestral" East African–Indian, the Delhi, and the Beijing/W genogroups. A few isolates from PGG2 lineages and a single representative of the presumably most recent PGG3 were identified. These observations suggest a predominance of ancestral M. tuberculosis genotypes in the Indian subcontinent, which supports the hypothesis that India is an ancient endemic focus of TB.

  • Extrapulmonary Tuberculosis by Nationality, the Netherlands, 1993–2001 PDF Version [PDF - 249 KB - 8 pages]
    L. A. te Beek et al.
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    The growth of the number of inhabitants with a non-Western ethnic background most likely explains the growth of extrapulmonary TB in the Netherlands.

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    This study describes the epidemiology of extrapulmonary tuberculosis (TB) in the Netherlands from 1993 through 2001. We assessed whether the increasing numbers of inhabitants with a non-Western ethnic background had an effect on the number of extrapulmonary patients. We used data from the Netherlands Tuberculosis Register and included all cases of TB diagnosed in the Netherlands between January 1, 1993, and December 31, 2001. Information on age, sex, nationality, year of diagnosis, culture result, anatomic location of the site of disease, and HIV status was retrieved from the register. Of 13,258 patients with TB, 8,216 (62%) had pulmonary TB, and 5,042 (38%) had extrapulmonary TB. Non-Dutch nationals were more likely to have most types of extrapulmonary TB. The growth of the number of inhabitants with a non-Western ethnic background in the Netherlands explains the proportional growth of extrapulmonary TB. Physicians need to be aware of the changing clinical picture of TB.

  • Risk for Tuberculosis among Children PDF Version [PDF - 127 KB - 6 pages]
    H. Nakaoka et al.
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    Risk among children is underestimated in countries with a high incidence of this disease.

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    Contacts of adults with tuberculosis (TB) are at risk for infection. Tests based on interferon-γ (IFN-γ) expression in response to Mycobacterium tuberculosis antigens may be more sensitive than the tuberculin skin test (TST). Risk for infection was assessed by using TST and an IFN-γ-based assay (QuantiFERON Gold in Tube [QFT-IT] test) for 207 children in Nigeria in 1 of 3 groups: contact with adults with smear-positive TB, contact with adults with smear-negative TB, and controls. For these 3 groups, respectively, TST results were >10 mm for 38 (49%) of 78, 13 (16%) of 83, and 6 (13%) of 46 and QFT-IT positive for 53 (74%) of 72, 8 (10%) of 81, and 4 (10.3%) of 39 (p<0.01). Most test discrepancies were TST negative; QFT-IT positive if in contact with TB-positive persons; and TST positive, QFT-IT negative if in contact with TB-negative persons or controls. TST may underestimate risk for infection with TB in children.

  • Multidrug-resistant Tuberculosis Management in Resource-limited Settings
    E. Nathanson et al.
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    Managing MDRTB through national programs can yield results similar to those seen in wealthier settings.

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    Evidence of successful management of multidrug-resistant tuberculosis (MDRTB) is mainly generated from referral hospitals in high-income countries. We evaluate the management of MDRTB in 5 resource-limited countries: Estonia, Latvia, Peru, the Philippines, and the Russian Federation. All projects were approved by the Green Light Committee for access to quality-assured second-line drugs provided at reduced price for MDRTB management. Of 1,047 MDRTB patients evaluated, 119 (11%) were new, and 928 (89%) had received treatment previously. More than 50% of previously treated patients had received both first- and second-line drugs, and 65% of all patients had infections that were resistant to both first- and second-line drugs. Treatment was successful in 70% of all patients, but success rate was higher among new (77%) than among previously treated patients (69%). In resource-limited settings, treatment of MDRTB provided through, or in collaboration with, national TB programs can yield results similar to those from wealthier settings.

  • Fluoroquinolones and Risk for Methicillin-Resistant Staphylococcus aureus, Canada PDF Version [PDF - 344 KB - 8 pages]
    L. LeBlanc et al.
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    Fluoroquinolones were associated with MRSA colonization and infection.

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    Receipt of fluoroquinolones was the predominant risk factor for Clostridium difficile–associated disease (CDAD) during an epidemic in Quebec, Canada. To determine the role of antimicrobial drugs in facilitating healthcare-associated methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection and to compare this role with their effects on methicillin-susceptible S. aureus infection and CDAD, we conducted a retrospective cohort study of patients in a Quebec hospital. For 7,371 episodes of care, data were collected on risk factors, including receipt of antimicrobial drugs. Crude and adjusted hazard ratios (AHR) were calculated by Cox regression. Of 150 episodes of MRSA colonization and 23 of MRSA infection, fluoroquinolones were the only antimicrobials that increased risk for colonization (AHR 2.57, 95% confidence interval [CI] 1.84–3.60) and infection (AHR 2.49, 95% CI 1.02–6.07). Effect of antimicrobial drugs on MRSA colonization and infection was similar to effect on CDAD and should be considered when selecting antimicrobial drugs to treat common infections.

  • Differentiation of Tuberculosis Strains in a Population with Mainly Beijing-family Strains PDF Version [PDF - 264 KB - 8 pages]
    V. Nikolayevskyy et al.
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    A new panel of 25 VNTR-MIRU loci differentiates Beijing-family TB strains better than a panel of 15.

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    A high prevalence of tuberculosis (TB) isolates that are genetically homogenous and from the Beijing family has been reported in Russia. To map TB transmission caused by these strains, new genotyping systems are needed. Mycobacterial interspersed repetitive units (MIRUs) offer the possibility of rapid PCR-based typing with comparable discrimination to IS6110 restriction fragment length polymorphism techniques. Spoligotyping and detection of IS6110 insertion in the dnaA-dnaN region were used to identify Beijing strains in 187 Mycobacterium tuberculosis isolates from Samara, Russia. The Beijing isolates were analyzed by using 12-MIRU and 3–exact tandem repeats (ETR) loci and by an expanded set of 10 additional variable number tandem repeats loci. The expanded set of 25 MIRUs provided better discrimination than the original set of 15 (Hunter-Gaston diversity index 0.870 vs 0.625). Loci MIRU 26, 1982, and 3232 were the most polymorphic in Beijing isolates.

Policy Review

  • State Plans for Containment of Pandemic Influenza PDF Version [PDF - 133 KB - 4 pages]
    S. D. Holmberg et al.
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    Current plans for control of pandemic influenza vary, and many do not include nonpharmaceutical interventions.

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    This review assesses differences and similarities of the states in planning for pandemic influenza. We reviewed the recently posted plans of 49 states for vaccination, early epidemic surveillance and detection, and intraepidemic plans for containment of pandemic influenza. All states generally follow vaccination priorities set by the Advisory Committee on Immunization Practices. They all also depend on National Sentinel Physician Surveillance and other passive surveillance systems to alert them to incipient epidemic influenza, but these systems may not detect local epidemics until they are well established. Because of a lack of epidemiologic data, few states explicitly discuss implementing nonpharmaceutical community interventions: voluntary self-isolation (17 states [35%]), school or other institutional closing (18 [37%]), institutional or household quarantine (15 [31%]), or contact vaccination or chemoprophylaxis (12 [25%]). This review indicates the need for central planning for pandemic influenza and for epidemiologic studies regarding containment strategies in the community.

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