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.

Expansion of zoonotic babesiosis and reported human cases, Connecticut, 2001-2010.

To document the expansion of human babesiosis in Connecticut, we analyzed reservoir host sera for seroreactivity to Babesia microti Franca and reviewed Connecticut human surveillance case data collected during 2001-2010. Sera from white-footed mice, Peromyscus leucopus Rafinesque, from 10 towns in 5 counties, collected at 4-7-yr periods between 2001 and 2010, were tested for total immunoglobulins. The prevalence of B. microti-positive mice was compared with confirmed and probable human case reports tabulated by the Connecticut Department of Public Health. The highest babesiosis and rodent seroprevalence rates were in New London County, where this protozoan disease was first documented in the state. However, human cases and reservoir host infection increased significantly from 2001-2005 to 2005-2010 and in other parts of the state. Clinicians should be aware that the disease is not confined to long-established endemic areas of the state.

Effect of surveillance method on reported characteristics of Lyme disease, Connecticut, 1996-2007.

To determine the effect of changing public health surveillance methods on the reported epidemiology of Lyme disease, we analyzed Connecticut data for 1996-2007. Data were stratified by 4 surveillance methods and compared. A total of 87,174 reports were received that included 79,896 potential cases. Variations based on surveillance methods were seen. Cases reported through physician-based surveillance were significantly more likely to be classified as confirmed; such case-patients were significantly more likely to have symptoms of erythema migrans only and to have illness onset during summer months. Case-patients reported through laboratory-based surveillance were significantly more likely to have late manifestations only and to be older. Use of multiple surveillance methods provided a more complete clinical and demographic description of cases but lacked efficiency. When interpreting data, changes in surveillance method must be considered.