Under the Weather: Legionellosis and Meteorological Factors.

The incidence of legionellosis, caused by the bacteria Legionella which are commonly found in the environment, has been increasing in New Jersey (NJ) over the last decade. The majority of cases are sporadic with no known source of exposure. Meteorological factors may be associated with increases in legionellosis. Time series and case-crossover study designs were used to evaluate associations of legionellosis and meteorological factors (temperature (daily minimum, maximum, and mean), precipitation, dew point, relative humidity, sea level pressure, wind speed (daily maximum and mean), gust, and visibility). Time series analyses of multi-factor models indicated increases in monthly relative humidity and precipitation were positively associated with monthly legionellosis rate, while maximum temperature and visibility were inversely associated. Case-crossover analyses of multi-factor models indicated increases in relative humidity occurring likely before incubation period was positively associated, while sea level pressure and visibility, also likely preceding incubation period, were inversely associated. It is possible that meteorological factors, such as wet, humid weather with low barometric pressure, allow proliferation of Legionella in natural environments, increasing the rate of legionellosis.

Notes from the field: update on Lyme carditis, groups at high risk, and frequency of associated sudden cardiac death--United States.

On December 13, 2013, MMWR published a report describing three cases of sudden cardiac death associated with Lyme carditis. State public health departments and CDC conducted a follow-up investigation to determine 1) whether carditis was disproportionately common among certain demographic groups of patients diagnosed with Lyme disease, 2) the frequency of death among patients diagnosed with Lyme disease and Lyme carditis, and 3) whether any additional deaths potentially attributable to Lyme carditis could be identified. Lyme disease cases are reported to CDC through the Nationally Notifiable Disease Surveillance System; reporting of clinical features, including Lyme carditis, is optional. For surveillance purposes, Lyme carditis is defined as acute second-degree or third-degree atrioventricular conduction block accompanying a diagnosis of Lyme disease. During 2001-2010, a total of 256,373 Lyme disease case reports were submitted to CDC, of which 174,385 (68%) included clinical information. Among these, 1,876 (1.1%) were identified as cases of Lyme carditis. Median age of patients with Lyme carditis was 43 years (range = 1-99 years); 1,209 (65%) of the patients were male, which is disproportionately larger than the male proportion among patients with other clinical manifestations (p<0.001). Of cases with this information available, 69% were diagnosed during the months of June-August, and 42% patients had an accompanying erythema migrans, a characteristic rash. Relative to patients aged 55-59 years, carditis was more common among men aged 20-39 years, women aged 25-29 years, and persons aged ≥75 years.