Archive for the ‘Emerging Infectious Diseases’ Category

Chicken as Reservoir for Extraintestinal Pathogenic Escherichia coli in Humans, Canada

March 23, 2012 Comments off
Source:  Emerging Infectious Diseases (CDC)
We previously described how retail meat, particularly chicken, might be a reservoir for extraintestinal pathogenic Escherichia coli (ExPEC) causing urinary tract infections (UTIs) in humans. To rule out retail beef and pork as potential reservoirs, we tested 320 additional E. coli isolates from these meats. Isolates from beef and pork were significantly less likely than those from chicken to be genetically related to isolates from humans with UTIs. We then tested whether the reservoir for ExPEC in humans could be food animals themselves by comparing geographically and temporally matched E. coli isolates from 475 humans with UTIs and from cecal contents of 349 slaughtered animals. We found genetic similarities between E. coli from animals in abattoirs, principally chickens, and ExPEC causing UTIs in humans. ExPEC transmission from food animals could be responsible for human infections, and chickens are the most probable reservoir.

Active Tuberculosis among Homeless Persons, Toronto, Ontario, Canada, 1998–2007

March 25, 2011 Comments off

Active Tuberculosis among Homeless Persons, Toronto, Ontario, Canada, 1998–2007 (PDF)
Source: Emerging Infectious Diseases

While tuberculosis (TB) in Canadian cities is increasingly affecting foreign-born persons, homeless persons remain at high risk. To assess trends in TB, we studied all homeless persons in Toronto who had a diagnosis of active TB during 1998–2007. We compared Canada-born and foreign-born homeless persons and assessed changes over time. We identified 91 homeless persons with active TB; they typically had highly contagious, advanced disease, and 19% died within 12 months of diagnosis. The proportion of homeless persons who were foreign-born increased from 24% in 1998–2002 to 39% in 2003–2007. Among foreign-born homeless persons with TB, 56% of infections were caused by strains not known to circulate among homeless persons in Toronto. Only 2% of infections were resistant to first-line TB medications. The rise in foreign-born homeless persons with TB strains likely acquired overseas suggests that the risk for drug-resistant strains entering the homeless shelter system may be escalating.

Tuberculosis Outbreak Investigations in the United States, 2002–2008

March 25, 2011 Comments off

Tuberculosis Outbreak Investigations in the United States, 2002–2008 (PDF)
Source: Emerging Infectious Diseases

To understand circumstances of tuberculosis transmission that strain public health resources, we systematically reviewed Centers for Disease Control and Prevention (CDC) staff reports of US outbreaks in which CDC participated during 2002–2008 that involved >3 culture-confirmed tuberculosis cases linked by genotype and epidemiology. Twenty-seven outbreaks, representing 398 patients, were reviewed. Twenty-four of the 27 outbreaks involved primarily US-born patients; substance abuse was another predominant feature of outbreaks. Prolonged infectiousness because of provider- and patient-related factors was common. In 17 outbreaks, a drug house was a notable contributing factor. The most frequently documented intervention to control the outbreak was prioritizing contacts according to risk for infection and disease progression to ensure that the highest risk contacts were completely evaluated. US- born persons with reported substance abuse most strongly characterized the tuberculosis outbreaks in this review. Substance abuse remains one of the greatest challenges to controlling tuberculosis transmission in the United States.

Elephant-to-Human Transmission of Tuberculosis, 2009

March 22, 2011 Comments off

Elephant-to-Human Transmission of Tuberculosis, 2009 (PDF)
Source: Emerging Infectious Diseases

In 2009, the Tennessee Department of Health received reports of 5 tuberculin skin test (TST) conversions among employees of an elephant refuge and isolation of Mycobacterium tuberculosis from a resident elephant. To determine the extent of the outbreak and identify risk factors for TST conversion, we conducted a cohort study and onsite assessment. Risk for conversion was increased for elephant caregivers and administrative employees working in the barn housing the M. tuberculosis–infected elephant or in offices connected to the barn (risk ratio 20.3, 95% confidence interval 2.8–146.7). Indirect exposure to aerosolized M. tuberculosis and delayed or inadequate infection control practices likely contributed to transmission. The following factors are needed to reduce risk for M. tuberculosis transmission in the captive elephant industry: increased knowledge about M. tuberculosis infection in elephants, improved infection control practices, and specific occupational health programs.

New Avian Influenza Virus (H5N1) in Wild Birds, Qinghai, China

February 27, 2011 Comments off

New Avian Influenza Virus (H5N1) in Wild Birds, Qinghai, China
Source: Emerging Infectious Diseases

In May 2005, highly pathogenic avian influenza (HPAI) virus (H5N1) caused a disease outbreak in wild birds in the Qinghai Lake region of the People’s Republic of China (1). Subsequently, this virus (QH05, clade 2.2) disseminated from Asia to Europe and Africa, which has led to great concern and energetic debates about the role of migratory birds in influenza epidemics (1–5). In 2006, this virus was detected in migratory birds in Qinghai (6,7). In 2007, viruses similar to QH05 were isolated from surveyed anseriformes in Qinghai and showed only a short evolutionary distance from earlier viruses (8). Genetic diversity of avian influenza viruses (H5N1) was not detected in wild birds in Qinghai before 2008 (7,8). We report evidence that a second lineage of viruses, in addition to clade 2.2, has emerged in wild birds in Qinghai.


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