Monthly Archives: May 2015

Cambridge Journals

A longitudinal study of nasal colonization and hand contamination of food handlers with Staphylococcus aureus commenced in 2002 prior to the outbreak of severe acute respiratory syndrome. In the follow-up in 2003 when hygiene measures were strictly implemented, significant reductions in carriage were observed. To investigate if this change was sustained, nasal and hand carriage rates were compared between the earlier studies and a further sampling in 2011. The initial nasal carriage rate was 35% and hand contamination 41·2%, decreasing to 23·5% and 11·6%, respectively in 2003 (P < 0·001). In 2011, nasal carriage was similar to 2003 (22·9%), while hand contamination dropped further to 3·7% (P < 0·001). Spa-typing revealed 39 types in 2002 and 42 in 2011. This study reveals that the marked reduction in colonization had been sustained. This may be attributed to reduced opportunities for spread due to enhanced hygiene and reinforces its importance for control of disease.

Cambridge Journals 

Norovirus is the most frequent cause of acute infectious gastroenteritis and it is difficult to control in crowded environments like hospitals and nursing homes. Transmission depends on oral intake of virus deposited in the environment by infectious subjects. Data from volunteer studies indicate that virus concentrations in stool are highly variable, but systematic studies of the time-course of shedding and its individual variation are lacking. This paper quantifies norovirus shedding in a large population of 102 subjects, including asymptomatic shedders, and uses a longitudinal model to generalize shedding patterns. Enhanced surveillance for studies of transmission of norovirus in hospital outbreaks has yielded a considerable number of faecal samples from symptomatic and asymptomatic shedders, both from patients and staff. Norovirus concentrations were determined by real-time PCR. A quantitative dynamic model was fitted to the shedding data, in a multilevel Bayesian framework, to study the time-course of shedding and its variation. The results indicate that shedding in asymptomatic subjects is similar to that in symptomatic infections, both showing considerable variation in peak levels (average 10⁵−10⁹ /g faeces) as well as duration of virus shedding (average 8–60 days). Patients appear to shed higher numbers of virus than staff, for slightly longer durations, but the differences are too small to be significant. Given equal shedding, the greater contribution of symptomatic cases to transmission must be caused by their higher efficiency in spreading these viruses. The results of this study will be helpful for risk studies that need to quantify the deposition of virus in the environment.

Eurosurveillance

 Portugal, listeriosis has been notifiable since April 2014, but there is no active surveillance programme for the disease. A retrospective study involving 25 national hospitals led to the detection of an outbreak that occurred between March 2009 and February 2012. The amount of time between the start of the outbreak and its detection was 16 months.  Of the 30 cases of listeriosis reported, 27 were in the Lisbon and Vale do Tejo region. Two cases were maternal/neonatal infections and one resulted in fetal loss. The mean age of the non-maternal/neonatal cases was 59 years (standard deviation: 17); 13 cases were more than 65 years-old. The case fatality rate was 36.7%. All cases were caused by molecular serogroup IVb isolates indistinguishable by pulsed-field gel electrophoresis and ribotype profiles. Collaborative investigations with the national health and food safety authorities identified cheese as the probable source of infection, traced to a processing plant. The magnitude of this outbreak, the first reported food-borne listeriosis outbreak in Portugal, highlights the importance of having an effective listeriosis surveillance system in place for early detection and resolution of outbreaks, as well as the need for a process for the prompt submission of Listeria monocytogenes isolates for routine laboratory typing.

Whatcom County

The Whatcom County Health Department (WCHD) is investigating an outbreak of shiga toxin-producing E. coli (STEC) associated with the Milk Makers Fest at the Northwest Fairgrounds in Lynden on 4/21 – 4/23/15. Over a thousand primary school children from all of the school districts in Whatcom County attended the event.

WCHD is interviewing the ill students and their parents to identify whether there was a common food or water source or activity, such as the petting zoo or other livestock contact. We are also monitoring for spread to other household members. We have contacted medical providers in Whatcom County about the outbreak and have asked them to obtain stool cultures and notify us of any cases of diarrhea in patients that attended the event in Lynden.

As of this afternoon, six cases have been identified that are associated with the event. Five of the cases are primary school children who attended the event. Three of the five had stool cultures that were positive for E. coli, presumed O157 (with confirmation pending at the WA State Laboratory), and were positive for shiga toxin 2. Two of the children did not have tests done, but have symptoms consistent with STEC and the exposure history. Another older child who was associated with the event has lab confirmed STEC. Two of the lab confirmed cases have been hospitalized. Another adult, without a known connection to the Milk Makers Fest or to any of the cases, has also been hospitalized with lab-confirmed STEC.

CFIA 

The Food Recall warning issued on April 29, 2015 has been amended to correctly identify the products recalled by Sun Rich Fresh Foods Inc. The corrections for these products are marked by an asterisk (*) below. Please note that the Starbucks product has been removed from this recall.

Sun Rich Fresh Foods Inc. is recalling sliced apples and products containing sliced apples produced in its Brampton, Ontario facility from the marketplace due to possible Listeria monocytogenes contamination. Consumers should not consume and distributors, retailers and food service establishments such as hotels, restaurants, cafeterias, hospitals and nursing homes should not sell or use the recalled products described below.