Effects of drinking-water filtration on Cryptosporidium seroepidemiology, Scotland.

Continuous exposure to low levels of Cryptosporidium oocysts is associated with production of protective antibodies. We investigated prevalence of antibodies against the 27-kDa Cryptosporidium oocyst antigen among blood donors in 2 areas of Scotland supplied by drinking water from different sources with different filtration standards: Glasgow (not filtered) and Dundee (filtered). During 2006-2009, seroprevalence and risk factor data were collected; this period includes 2007, when enhanced filtration was introduced to the Glasgow supply. A serologic response to the 27-kDa antigen was found for ≈75% of donors in the 2 cohorts combined. Mixed regression modeling indicated a 32% step-change reduction in seroprevalence of antibodies against Cryptosporidium among persons in the Glasgow area, which was associated with introduction of enhanced filtration treatment. Removal of Cryptosporidium oocysts from water reduces the risk for waterborne exposure, sporadic infections, and outbreaks. Paradoxically, however, oocyst removal might lower immunity and increase the risk for infection from other sources.

Infections with spore-forming bacteria in persons who inject drugs, 2000-2009.

Since 2000 in the United Kingdom, infections caused by spore-forming bacteria have been associated with increasing illness and death among persons who inject drugs (PWID). To assess temporal and geographic trends in these illnesses (botulism, tetanus, Clostridium novyi infection, and anthrax), we compared rates across England and Scotland for 2000-2009. Overall, 295 infections were reported: 1.45 per 1,000 PWID in England and 4.01 per 1,000 PWID in Scotland. The higher rate in Scotland was mainly attributable to C. novyi infection and anthrax; rates of botulism and tetanus were comparable in both countries. The temporal and geographic clustering of cases of C. novyi and anthrax into outbreaks suggests possible contamination of specific heroin batches; in contrast, the more sporadic nature of tetanus and botulism cases suggests that these spores might more commonly exist in the drug supply or local environment although at varying levels. PWID should be advised about treatment programs, injecting hygiene, risks, and vaccinations.

Anthrax infection among heroin users in Scotland during 2009-2010: a case-control study by linkage to a national drug treatment database.

Using a data-linkage approach, we conducted a case-control study to investigate risk factors in an outbreak of anthrax infection among Scottish heroin users. Factors associated with an increased risk of infection included longer injecting history, receiving opioid substitution therapy, and alcohol consumption. Smoking heroin was associated with lower risk of infection.

Cardiovascular disease and air pollution in Scotland: no association or insufficient data and study design?

BACKGROUND: Coronary heart disease and stroke are leading causes of mortality and ill health in Scotland, and clear associations have been found in previous studies between air pollution and cardiovascular disease. This study aimed to use routinely available data to examine whether there is any evidence of an association between short-term exposure to particulate matter (measured as PM10, particles less than 10 micrograms per cubic metre) and hospital admissions due to cardiovascular disease, in the two largest cities in Scotland during the years 2000 to 2006. METHODS: The study utilised an ecological time series design, and the analysis was based on overdispersed Poisson log-linear models. RESULTS: No consistent associations were found between PM10 concentrations and cardiovascular hospital admissions in either of the cities studied, as all of the estimated relative risks were close to one, and all but one of the associated 95% confidence intervals contained the null risk of one. CONCLUSIONS: This study suggests that in small cities, where air quality is relatively good, then either PM10 concentrations have no effect on cardiovascular ill health, or that the routinely available data and the corresponding study design are not sufficient to detect an association.

Investigation of accidental secondary exposure to CS agent.

We report on an unusual exposure to o-chlorobenzylidene malononitrile (CS agent) following its use to detect unauthorized stowaways aboard a vehicle, and the subsequent handling of the cargo delivered to retail stores across Scotland. Twenty-one staff in 16 retail stores across Scotland experienced symptoms including itching and running eyes, rhinorhoea, a burning sensation on the face and hands, and a burning throat, following the furniture deliveries. A survey was conducted to assess the extent of exposure to the contaminated furniture and the scale of illness associated with exposure. Experiencing symptoms was significantly associated with having contact with the furniture or packaging (chi(2) = 10.5, p < 0.001). This incident demonstrates the risk of inadvertent secondary exposure and subsequent acute symptoms from contact with residual CS agent when sprayed in the confined spaces of haulage vehicles.

Cryptosporidiosis and filtration of water from Loch Lomond, Scotland.

Previous evidence has suggested an association between consumption of unfiltered water from Loch Lomond, Scotland, and cryptosporidiosis. Before November 1999, this water had been only microstrained and disinfected with chlorine; however, since that time, physical treatment of the water (coagulation, rapid gravity filtration) has been added. To determine risk factors, including drinking water, for cryptosporidiosis, we analyzed data on laboratory-confirmed cases of cryptosporidiosis collected from 1997 through 2003. We identified an association between the incidence of cryptosporidiosis and unfiltered drinking water supplied to the home. The association supports the view that adding a filtration system to minimally treated water can substantially reduce the number of confirmed cryptosporidiosis cases.