Since its identification nearly 30 years ago, Lyme disease has continued to spread, and there have been increasing numbers of cases in the northeastern and north central US. The Lyme disease agent, Borrelia burgdorferi, causes infection by migration through tissues, adhesion to host cells, and evasion of immune clearance. Both innate and adaptive immune responses, especially macrophage- and antibody-mediated killing, are required for optimal control of the infection and spirochetal eradication. Ecological conditions favorable to the disease, and the challenge of prevention, predict that Lyme disease will be a continuing public health concern

We studied 20 patients, mostly young adult men, with cardiac involvement of Lyme disease. The commonest abnormality (18 patients) was fluctuating degrees of atrioventricular block; eight of them developed complete heart block. Thirteen patients had evidence of more diffuse cardiac involvement: electrocardiographic changes compatible with acute myopericarditis (11 patients), radionuclide evidence of mild left ventricular dysfunction (five of 12 patients tested), or frank cardiomegaly (one patient). Heart involvement was usually preceded by erythema chronicum migrans and sometimes accompanied by meningoencephalitis, facial palsy, arthritis, elevated serum IgM levels, or cryoglobulins containing IgM. The duration of cardiac involvement was usually brief (3 days to 6 weeks). The clinical picture in these patients has similarities to acute rheumatic fever; but in Lyme disease, complete heart block may be commoner, myopericardial involvement tends to be milder, and valves seem not to be affected.

During 1980 and 1981, we compared antibiotic regimens in 108 adult patients with early Lyme disease. Erythema chronicum migrans and its associated symptoms resolved faster in penicillin- or tetracycline-treated patients than in those given erythromycin (mean duration, 5.4 and 5.7 versus 9.2 days, F = 3.38, p less than 0.05). None of 39 patients given tetracycline developed major late complications (meningoencephalitis, myocarditis, or recurrent attacks of arthritis) compared with 3 of 40 penicillin-treated patients and 4 of 29 given erythromycin (chi square with 2 degrees of freedom = 5.33, p = 0.07). In 1982, all 49 adult patients were given tetracycline; again, none of them developed major complications. However, with all three antibiotic agents nearly half of the patients had minor late symptoms such as headache, musculoskeletal pain, and lethargy. These complications correlated significantly with the initial severity of illness. For patients with early Lyme disease, tetracycline appears to be the most effective drug, then penicillin, and finally erythromycin.

Tick bites and prophylaxis. The best currently available method for preventing infection with Borrelia burgdorferi is to avoid vector tick exposure. If exposure to Ixodes scapularis or Ixodes pacificus ticks is unavoidable, measures recommended to reduce the risk of infection include using both protective clothing and tick repellents, checking the entire body for ticks daily, and promptly removing attached ticks, before transmission of B. burgdoiferi can occur (A-III [see tables 1 and 2 for recommendation categories, indicated in parentheses throughout this text]). Routine use of either antimicrobial prophylaxis (E-I) or serological tests (D-III) after a tick bite is not recommended. Some experts recommend antibiotic therapy for patients bitten by I. scapularis ticks that are estimated to have been attached for >48 h (on the basis of the degree of engorgement of the tick with blood), in conjunction with epidemiological information regarding the prevalence of tick-transmitted infection (C-III). However, accurate determinations of species of tick and degree of engorgement are not routinely possible, and data are insufficient to demonstrate efficacy of antimicrobial therapy in this setting. Persons who remove attached ticks should be monitored closely for signs and symptoms of tick-borne diseases for up to 30 days and specifically for the occurrence of a skin lesion at the site of the tick bite (which may suggest Lyme disease) or a temperature >38?C (which may suggest human granulo

Handwashing is generally considered the most important procedure in preventing nosocomial infections, because many types of these infections may be caused by organisms transmitted on the hands of personnel. Personnel should wash their hands before and after significant contact with any patient. The risk of personnel acquiring transient hand carriage of organisms is usually greatest after contact with excretions, secretions, or blood; patients at greatest risk are those undergoing surgery, those with catheters, and newborn infants. Although handwashing with an antiseptic agent between patient contacts is theoretically desirable, handwashing with soap, water, and mechanical friction are sufficient ro remove most transiently acquired organisms. Antiseptic agents may produce excessively dry skin if used frequently, and any regimen of handwashing that leads to dermatitis negates the purpose of handwashing. We favor antiseptics for handwashing before surgery and other high-risk invasive procedures and in the care of newborn infants but prefer soap and water for other handwashing.