News Scan for Aug 21, 2015

NY Legionella source
;
H5N6 in Vietnam
;
C diff virulence
;
Jamboree-linked meningococcal disease outbreak
;
Airborne spread of swine viruses

NY Legionnaires' disease outbreak source identified in South Bronx

Officials identified a cooling tower at the Opera House Hotel in New York City's South Bronx as the source of a recent outbreak of Legionnaires' disease, according to a New York City Department of Health and Mental Hygiene (DHMH) press release yesterday.

The health department also confirmed that, given no new cases or onset of symptoms since Aug 3, the outbreak is officially over.

The outbreak began in mid-July and has since sickened 124 people and caused 12 deaths. All deaths occurred in people with underlying medical conditions.

City officials reported on Aug 10 that 18 cooling towers had tested positive for Legionella. Bacteria from the historic Opera House Hotel in the South Bronx matched the outbreak strain obtained from 25 patients.

All New York City building owners with cooling towers have until Aug 27 to comply with a Commissioner's Order that requires disinfection and maintenance of inspection records. Cooling towers must be registered with the City by Sep 17.

The Opera House Hotel is more than 100 years old, and the affected cooling tower is 2 years old, according to a CBS story. Hotel and city personnel continue to monitor for potential new cases and conduct outreach to vulnerable populations.
Aug 20 DHMH press release
Aug 20 CBS New York story

 

Vietnam reports H5N6 outbreak in northern province

Animal health officials in Vietnam said a highly pathogenic H5N6 outbreak has been detected in backyard poultry in Lao Cai province, located in the far northern part of the country, according to a report yesterday from the World Organization for Animal Health (OIE).

The outbreak began on Aug 18. Of 700 susceptible birds, the virus killed 200, and the remaining ones were slated for culling.

Vietnam reported its first outbreak of H5N6, then described as a new strain, in August 2014, and since then it has reported sporadic events involving the strain.
Aug 20 OIE report
Aug 13, 2014, CIDRAP News scan "Vietnam reports 2 outbreaks of new H5N6 avian flu strain in poultry"

 

C diff clinical disease, not strain, found to be better predictor of outcome

Different strains of Clostridium difficile are almost equally virulent, making clinical presentation of infection the more important predictor of severe outcomes, according to findings of a study published yesterday in Infection Control and Hospital Epidemiology.

In a multicenter investigation of C diff infection at seven hospitals in Houston, Tex., researchers evaluated the association between six C diff ribotypes, clinical disease severity, and severe outcomes. Ribotypes were identified with multiplex polymerase chain reaction techniques and fluorescent ribotyping.

The study, carried out from 2011 to 2013, included 715 patients whose stool samples tested positive for C diff; 257 (36%) had severe infection (defined as leukocytosis and/or hypoalbuminemia), and 88 (12%) experienced a severe outcome. C diff ribotypes identified included 027, 014-020, FP311, 002, 078-126, 001.

Leukocytosis was the most common sign in patients with severe infection, affecting 131 (18%), followed by hypoalbuminemia in 63 (9%) and both leukocytosis and hypoalbuminemia in 63 (9%).

Severe outcomes included admission to the intensive care unit (54 patients, or 8%), death (44, or 6%), ileus (11, or 2%), toxic megacolon (7, or 1%), colectomy (6, or 0.8%), and pseudomembranous colitis (3, or 0.4%).

Ribotype 027 (R027) significantly predicted severe disease (adjusted odds ratio [aOR], 2.24; 95% confidence interval [CI], 1.53-3.29; P < 0.001) and severe outcomes (aOR, 1.71; 95% CI, 1.02-2.85, P = 0.041) when compared with the other ribotypes in aggregate. However, when R027 was compared with individual ribotypes and considered alongside age and treatment data, it did not predict severe outcomes more than other ribotypes.

Severe clinical disease was significantly associated with severe outcomes (aOR, 4.19; 95% CI, 2.46-8.07; P < 0.001). Severe disease was observed more commonly in patients with R027 than with other ribotypes (19% versus 10% of patients).

Results highlighted the importance of monitoring signs and progression of clinical C diff disease rather thanstrain virulence as an indicator of severe outcome risk.
Aug 20 Infect Control Hosp Epidemiol study

 

ECDC warns of invasive meningococcal disease cases linked to scout event

The European Centre for Disease Prevention and Control (ECDC) today warned of cases of invasive meningococcal disease in scouts who recently attended a world jamboree in Japan that attracted about 33,000 participants from 162 countries.

So far only two countries—Sweden and the United Kingdom—have reported cases. Of eight reported so far, four are from Sweden and four are from the UK. The total includes five confirmed and three suspected cases.

In its risk assessment, the ECDC said multicountry meningococcal outbreaks linked to international mass gatherings have occurred in the past. It further stated that most of the scouts who took part in the recent jamboree, held from Jul 28 to Aug 8, are between the ages of 14 and 17, a group known to be at increased risk. The ECDC added that some who attended are from countries where the disease is highly endemic.

Lab results from two UK cases identified meningococcal serogroup W, and early findings from typing suggest that the strain matches a strain increasingly detected in England since 2009. Identifying the index case can be difficult, because it's not unusual for young people to be asymptomatic carries, the ECDC said.

So far no connections between the cases has been found, but the ECDC said close contact between participants at the jamboree is thought to be high, and that scout groups from Finland, France, Sweden, Switzerland, and the United States stayed in tents close to the UK-unit campsites.

The ECDC said more cases could be reported, due to delays in seeking care and in health facility reporting. It added that more cases in contacts of infected participants are possible.
Aug 21 ECDC risk assessment

 

Study fleshes out potential for airborne spread of pig viruses

Three viral pig diseases, including influenza A, can be transmitted through aerosols comprising a wide range of particle sizes and in environmental conditions similar to those where humans and the animals interact, according to a research team based at the University of Minnesota.

The group published its findings from investigations involving pigs experimentally infected with influenza A, porcine reproductive and respiratory syndrome virus (PRRSV), and porcine epidemic diarrhea virus (PEDV) Aug 19 in PLoS One.

The team noted that there is little information on particle size distribution for pathogens, with animal model information limited to ferrets and Guinea pigs, not animals raised in agricultural settings.

The researchers infected 5-week-old piglets with the viruses, first PRRSV and influenza A, and then 21 days later PEDV. Airborne sampling was done for 24 days, which also involved sorting the airborne particles according to size and testing the air samples for viruses. Investigators also tracked animals' clinical signs and other lab parameters.

Results showed that the sick pigs emitted all three viruses in a range of particle sizes that could be inhaled or swallowed. However, for influenza and PRRSV, virus viability depended on size, with isolation possible only in particles larger than 2.1 micrograms. PEDV, an enteric virus, was found in larger concentrations in the air than the other two viruses tested.

The group concluded that their findings support the role of aerosol transmission for the three viruses, that they can disperse at the same time through a range of particle sizes, and that they can be transmitted across both short and long distances.
Aug 19 PLoS One abstract

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