A large Great Britain-wide outbreak of STEC O157 phage type 8 linked to handling of raw leeks and potatoes.

Between December 2010 and July 2011, 252 cases of STEC O157 PT8 stx1 + 2 infection were reported in England, Scotland and Wales. This was the largest outbreak of STEC reported in England and the second largest in the UK to date. Eighty cases were hospitalized, with two cases of haemolytic uraemic syndrome and one death reported. Routine investigative data were used to generate a hypothesis but the subsequent case-control study was inconclusive. A second, more detailed, hypothesis generation exercise identified consumption or handling of vegetables as a potential mode of transmission. A second case-control study demonstrated that cases were more likely than controls to live in households whose members handled or prepared leeks bought unwrapped [odds ratio (OR) 40, 95% confidence interval (CI) 2·08-769·4], and potatoes bought in sacks (OR 13·13, 95% CI 1·19-145·3). This appears to be the first outbreak of STEC O157 infection linked to the handling of leeks.

Toxoplasma gondii dissemination: a parasite's journey through the infected host.

Toxoplasma gondii is a highly successful global pathogen that is remarkable in its ability to infect nearly any nucleated cell in any warm-blooded animal. Infection with T. gondii typically occurs through the ingestion of contaminated food or water, but the parasite then breaches the intestinal epithelial barrier and spreads from the lamina propria to a large variety of other organs in the body. A key feature of T. gondii pathogenesis is the parasite's ability to cross formidable biological barriers in the infected host and enter tissues such as the brain, eye and placenta. The dissemination of T. gondii into these organs underlies the severe disease that accompanies human toxoplasmosis. In this review, we will focus on seminal studies as well as exciting recent findings that have shaped our current understanding of the cellular and molecular mechanisms by which T. gondii journeys throughout the host and enters organs to cause disease.

National outbreaks of Salmonella infection in the UK, 2000-2011.

Over a 12-year period, the Health Protection Agency's (now Public Health England's) Department of Gastrointestinal and Emerging Infections (GEZI) investigated over 100 potential national outbreaks of Salmonella enterica. These ranged from a cluster of cases requiring data interrogation and monitoring of the situation, to full blown case-control studies involving hundreds of interviews, many staff, multi-agency collaboration and the media. Vehicles of infection ranged from the usual suspects of chicken and eggs, to the less frequently implicated snake feed and chocolate. This has forced us to alter our preconceptions of disease transmission. The way in which GEZI investigate outbreaks and conduct case-control studies is constantly evolving as we learn and adapt to the changing aetiology of S. enterica. We present the findings and lessons learned during the last 12 years of investigating S. enterica outbreaks in England and Wales.

An outbreak of Salmonella Typhimurium DT191a associated with reptile feeder mice.

In December 2008 an increase of tetracycline-resistant Salmonella Typhimurium definitive phage-type 191a (DT191a) was identified in England and Wales by the reference laboratory. This was confirmed to have a phage-typing pattern that had not previously been seen. Strong statistical evidence for an association between illness and keeping reptiles was demonstrated by a matched case-case study (mOR 16·82, 95% CI 2·78-∞). Questionnaires revealed an association with frozen reptile feeder mice, and mice representing 80% of the UK supply lines were tested for the presence of Salmonella. DT191a was found in three pools of sampled mice, which were traced back to a single supplier in the USA. Imports from this supplier were halted, and tighter regulations are now in place. A leaflet detailing how to prevent contracting Salmonella from pet reptiles has been published as well as updated advice on the Health Protection Agency's website.