Mary S. Holman

Clinical Characteristics and Treatment Outcome of Early Lyme Disease in Patients with Microbiologically Confirmed Erythema Migrans

Context Lyme disease is the most common vector-borne disease in the United States. The traditional clinical presentation, an expanding erythematous rash with partial central clearing, sometimes accompanied by systemic symptoms, was described in patients who usually had clinically manifest Lyme disease for several days. Contribution This study describes 118 patients who acquired Lyme disease while under surveillance in a vaccine trial. Fifty-nine percent of rashes were homogeneous lesions, 32% had dense central erythema, and only 9% had classic central clearing. Signs and symptoms usually resolved within 3 weeks of antibiotic treatment. Implications Early Lyme disease may present with homogeneous or dense central erythematous lesions rather than classic erythema migrans. With antibiotic treatment, the prognosis is excellent. Early Lyme disease may present with homogeneous or dense central erythematous lesions rather than classic erythema migrans. With antibiotic treatment, the prognosis is excellent. The Editors Lyme disease in the United States is caused by the tick-transmitted spirochete Borrelia burgdorferi sensu stricto (1). This infection is the most common vector-borne disease in the country (2). The illness usually presents with localized infection of the skin, erythema migrans, which is often followed days to a few weeks later by dissemination of the spirochete to multiple sites, particularly to other skin sites, the nervous system, the heart, or the joints (3). Borrelia burgdorferi has been cultured readily from skin biopsy samples of erythema migrans early in the illness (4, 5), but later culture from other sites has been difficult. As a substitute for culture, B. burgdorferi DNA may be detected by polymerase chain reaction (PCR) in most patients with erythema migrans (6, 7) and in the joint fluid of patients with Lyme arthritis (8, 9). However, PCR has had low sensitivity in samples from other sites, including cerebrospinal fluid and blood. Serodiagnosis is not sensitive during the first several weeks of infection, but patients often seroconvert during convalescence (10). The initial clinical series of patients with early Lyme disease (11) was described before identification of the causative agent. Researchers used clinical criteria for study entry, particularly the classic appearance of erythema migrans, a slowly expanding erythema with partial central clearing. In that series of 314 patients, most had systemic symptoms and nearly half also had multiple annular erythemas, suggesting dissemination of the spirochete to multiple sites. In a subsequent study, 79 patients from Westchester County, New York, with early Lyme disease had erythema migrans from which B. burgdorferi was cultured (12). Most of the patients in this series, who were often seen earlier than those in the original study, had systemic symptoms, but only 18% had multiple erythemas. In Europe, where erythema migrans more often results from infection with B. afzelii or B. garinii rather than B. burgdorferi sensu stricto, inflammation of erythema migrans is less intense and migration is slower; in addition, patients generally have fewer systemic symptoms (13). In the southeastern United States, patients have been reported to have erythema migranslike skin lesions, but laboratory evidence of B. burgdorferi infection has been lacking. This suggests that another agent, perhaps even from the Borrelia genus, may cause the infection in this geographic area (14-16). Moreover, the same tick that transmits the Lyme disease agent may transmit other infectious agents, including the agent of human granulocytic ehrlichiosis and Babesia microti, and co-infection may influence the clinical presentation of Lyme disease (17, 18). Thus, microbiological confirmation is beneficial in describing the clinical features of Lyme disease in endemic areas in the United States. The recent phase III study of SmithKline Beechams Lyme disease vaccine provided an exceptional opportunity to assess the clinical picture of early Lyme disease in a large cohort of patients who acquired the infection in major endemic locations throughout the United States (19). As part of the protocol, patients who had symptoms of Lyme disease were extensively evaluated for that infection. We describe the clinical presentation, serologic results, and treatment outcome of early Lyme disease in 118 patients with microbiologically confirmed cases of erythema migrans. Methods Patients A total of 10 936 participants 15 to 70 years of age were enrolled in a double-blind, placebo-controlled study of the efficacy and safety of an outer surface protein A Lyme disease vaccine (LYMErix, recombinant outer surface protein A, SmithKline Beecham [now GlaxoSmithKline], Collegeville, Pennsylvania) at 31 sites in 10 endemic states. The Human Investigations Review Committees at all participating centers approved the study protocol. The complete protocol, as well as all members of the Lyme Disease Vaccine Study Group, have been reported elsewhere (19). Briefly, study participants received a packet with information about Lyme disease. Participants were requested to report promptly to their clinician-investigator any symptoms that suggested infection, including onset of a new rash or flu-like illness (without predominant respiratory or gastrointestinal symptoms), arthralgias or arthritis, facial palsy, radiculopathy, or syncope. All participants who were thought to have possible Lyme disease underwent a focused history, physical examination, and laboratory testing. All clinical data were entered on an electronic data form for central analysis. Antibiotic treatment was prescribed according to recommended guidelines (20), but the actual antibiotic and the duration of treatment were at the discretion of the investigator or the patients personal physician. Of the 10 936 participants, 146 met study criteria for definite Lyme disease and 118 had an acute illness with culture-proven or PCR-confirmed erythema migrans. Two clinicians independently reviewed photographs of erythema migrans from case-patients. Laboratory Methods Serologic testing was done at the New England Medical Center exclusively by Western blot (MarDx, San Diego, California), since the standard enzyme-linked immunosorbent assay would be expected to yield positive results in patients vaccinated with outer surface protein A (21). A baseline sample was obtained at study entry, and acute and convalescent samples were obtained when the patient had symptoms suggestive of Lyme disease. The diagnosis of Lyme disease was serologically supported by IgM or IgG seroconversion, or both, between baseline and the acute phase of the illness or between the acute and convalescent phases of the illness. Samples from the same participant were always tested together in the same assay. Western blot results were interpreted according to the criteria of the Centers for Disease Control and Prevention and of the Association of State and Territorial Public Health Laboratory Directors (22). On Western blot, outer surface protein A antibodies bind to a 31-kilodalton band; this is not included in the Centers for Disease Control and Prevention criteria. Following local anesthesia, skin biopsy specimens from erythema migrans were obtained by using 2-mm punch biopsy. Half of each sample was placed directly into a 15-mL tube of BarbourStoennerKelly medium (BSK-H medium, Sigma-Aldrich, St. Louis, Missouri) with ciprofloxacin (0.4 g/mL) and rifampin (40 g/mL); the other half was placed in a 2-mL polypropylene plastic tube for PCR testing. Specimens were shipped the same day by Federal Express to New England Medical Center. On arrival at the laboratory, half of the medium was replaced with fresh medium. Skin samples for culture were placed in an incubator at 33 C and were examined weekly for 1 month by darkfield microscopy for motile spirochetes. Polymerase chain reaction assays of skin biopsy samples were performed as described elsewhere (8). Role of the Funding Source SmithKline Beecham provided data and gave the authors permission to review them, compile them, and independently present results. Dr. Parenti was employed as a research physician with SmithKline Beecham during the early phases of the study. Results During the 20-month study period, which covered two summers of Lyme disease transmission, 1917 of the 10 936 study participants were evaluated for possible Lyme disease (19). Of the 1917 patients, 146 (7.6%) met study criteria for definite Lyme disease, and 118 (6.2%) had microbiological confirmation of this infection by culture or PCR testing of erythema migrans. The mean age of these 118 patients was 51 years (range, 17 to 71 years); 53% were men, and 47% were women. Forty-seven percent were from New England, 51% were from mid-Atlantic states, and 2% were from Wisconsin, reflecting the locations of the study sites. June and July were the peak months of disease onset, which correlated with the expected peak questing period of nymphal Ixodes scapularis ticks. However, cases occurred from March through October, suggesting that adult ticks may also transmit the disease. Vaccine and placebo recipients did not differ in the size of erythema migrans, persistence of symptoms after treatment, and morphologic characteristics of the lesions. In addition, no clinical differences were noted in different geographic areas. Therefore, we present data from vaccine and placebo recipients and from different geographic areas together. Characteristics of Erythema Migrans One hundred eighteen patients had erythema migrans in which B. burgdorferi was detected by culture (88%); by PCR testing (72%); or, in most instances, by both methods (60%). Rashes, which were evaluated a median of 3 days after onset (range, 1 to 30 days), were a median of 10 cm in diameter (range, 5 to 37 cm) at the time of diagnosis. In this adult population, nearly half of the lesions were located on the groin, buttocks, or lo

Abundance of Ixodes scapularis (Acari: Ixodidae) after the complete removal of deer from an isolated offshore island, endemic for lyme disease

Abstract Monhegan is an isolated 237-ha island lying 16 km off the coast of Maine. Introduced to the island in 1955, white-tailed deer, Odocoileus virginianus Zimmerman, reached a density of ∼37/km2 by the mid-1990s. Black-legged ticks, Ixodes scapularis Say, first noticed in the late 1980s, flourished thereafter. Norway rats (Rattus norvegicus Berkenhout) on Monhegan are highly infected with Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt, and Brenner, the agent of Lyme disease. By 1996, 13% of year-round residents had contracted the disease. The community’s subsequent decision to eliminate deer from the island provided a unique opportunity to monitor the abundance of vector ticks in response to the complete and permanent removal of the primary hosts of their reproductive stage. With the exception of humans and their dogs and cats, there are no other potential hosts for adult I. scapularis on Monhegan. From November 1996 to March 1999, all deer were removed from the island. Previous annual fall flagging of vegetation from 1990 to 1998 produced 6–17 adult ticks/h, of which 24–41% were infected with the Lyme disease spirochete. During this same period, up to 18 larvae and 4 nymphs were removed per Norway rat live-trapped on the island each July. With the absence of deer in the fall of 1999, both the density of host-seeking adult ticks and infection prevalence rose substantially to 28/h and 75.0%, respectively. By the summer of 2003, however, no sub-adult ticks were found on rats, and that fall, only 0.67 adult ticks/h were flagged. Of the 68 adults collected from 2002 to 2003, 20 (29.4%) were infected. Over this same period, adult tick abundance on a deer-populated, reference island continued to gradually increase.

Deer Density and the Abundance of Ixodes scapularis (Acari: Ixodidae)

Abstract The abundance of Ixodes scapularis Say (Ixodes dammini Spielman, Clifford, Piesman & Corwin), the vector tick of the Lyme disease spirochete and other human pathogens, is related to the presence of its primary reproductive stage host, white-tailed deer (Odocoileus virginianus Zimmerman). However, this relationship has not been quantified in terms that would guide wildlife management in areas in which the public is, or is likely to become, exposed to infected ticks. In this study, deer density and tick abundance were measured in an emergent area for Lyme disease at three spatial scales using estimation methods appropriate for each. Simple linear regression was used to relate (1) the number of ticks found on deer at tagging stations in southern Maine to harvest-derived estimates of the density of deer within the towns in which they were killed, (2) tick densities estimated from fall flagging counts to deer densities estimated from pellet group counts made within multiple transects distributed through 5.2-km2 study sites, and (3) tick counts to pellet group counts within the individual transects. At the broadest scale, ticks on deer decreased with elevation and distance from the coast and increased with deer density, although deer and tick presence were only weakly related. Among the 5.2-km2 study sites and within individual transects, tick abundance related more strongly to deer pellet group counts. Few ticks were collected at deer densities <7/km2.

Anaplasma phagocytophilum, Babesia microti, and Borrelia burgdorferi in Ixodes scapularis, southern coastal Maine.

Ixodes scapularis (deer ticks) from Maine were tested for multiple infections by polymerase chain reaction and immunofluorescence. In 1995, 29.5%, 9.5%, and 1.9% of deer ticks were infected with Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti, respectively. In 1996 and 1997, the number of A. phagocytophilum-infected ticks markedly declined. In 1995 through 1996, 4 (1.3%) of 301 were co-infected.

Habitat Associations of Ixodes scapularis (Acari: Ixodidae) in Maine

Abstract The habitat associations of Ixodes scapularis Say (=I. dammini Spielman, Clifford, Piesman, and Corwin) were examined at the northern edge of its range. We assessed the association of habitat features with the abundance of ticks by flagging for questing adult I. scapularis at three sites in coastal Maine from 1998 to 2000 along 27 305-m transects. Multivariable logistic regression indicated that probability of tick abundance was greater in the presence of shrub layer, canopy closure >50%, deciduous litter, forest grasses, and moist-soil ferns. In a second model that related I. scapularis abundance to canopy- and shrub-layer species, probability of tick abundance was greater in the presence of Japanese barberry Berberis thunbergii DC, winterberry holly Ilex verticillata L. (Gray), and Eurasian honeysuckle Lonicera spp., and less with the presence of eastern hemlock saplings Tsuga canadensis L. (Carr.). These associations were true despite variation in deer abundance as indicated by deer pellet group counts. Natural resource managers should be aware that landscape changes, including the invasion by exotic vegetation, might create favorable tick habitat. These findings could prove helpful in assessing local risk of exposure to this vector tick.

Deer Browse Resistant Exotic-Invasive Understory: An Indicator of Elevated Human Risk of Exposure to Ixodes scapularis (Acari: Ixodidae) in Southern Coastal Maine Woodlands

Abstract We evaluated the relationships between forest understory structure and the abundance of questing adult and nymphal blacklegged ticks, Ixodes scapularis Say (Acari: Ixodidae), in three Maine towns endemic for Lyme disease, 2001–2003. In fragmented New England woodlands, overabundant white-tailed deer, Odocoileus virginianus Zimmerman, overbrowse palatable species, allowing browse-resistant exotic-invasive species to replace native forest understory structures. We predicted there would be more ticks in plots dominated by exotic-invasive shrubs (such as Japanese barberry, Berberis thunbergii DC) than in plots dominated by native shrubs, ferns, or open understory. We assessed canopy composition and closure, tree basal area, litter composition, percentage of coverage and stem density of understory species, litter depth, soil moisture, and abundance of small mammals and white-tailed deer pellet groups. We used generalized linear mixed model analysis of covariance to determine the effect of understory structure on tick counts, controlling for continuous habitat and host covariates and adjusting for random spatial effects. There were twice as many adults and nearly twice as many nymphs in plots dominated by exotic-invasives than in plots dominated by native shrubs. Both adult and nymphal counts were lowest in open understory with coniferous litter. Adults were positively associated with increasing litter depth, medium soil moisture, and increasing abundance of white-footed deer mice, Peromyscus leucopus Rafinesque, and deer pellet group counts. Nymphs were positively associated with increasing litter depth, moderately wet soil, and mice. We concluded that deer browse-resistant exotic-invasive understory vegetation presented an elevated risk of human exposure to the vector tick of Lyme disease.

Attempt to Control Ticks (Acari: Ixodidae) on Deer on an Isolated Island Using Ivermectin-Treated Corn

Abstract We report an attempt by an offshore island community to control the vector tick of Lyme disease by providing ivermectin-treated corn to an isolated herd of free-ranging white-tailed deer, 0docoileus virginianus Zimmerman. Medicated corn was supplied in troughs within the island village and from automatic feeders at remote sites during 5 consecutive fall and spring adult tick questing seasons. Acaricide consumption was monitored by assaying its presence in fresh deer pellets and its concentration in deer sera. Its effectiveness was evaluated by recording the number of adult ticks collected from the hides of deer, the number of females becoming sufficiently engorged to oviposit, and the success of subsequent oviposition and eclosion. Entomologic risk was monitored by collecting immature ticks from hosts and adult ticks from vegetation. Estimates based on a subsequent deer reduction program indicated that up to twice as many deer had been present during the project as originally presumed. For this and other reasons related to deer behavior, target levels of serum ivermectin were achieved in a minority of deer. Nevertheless, >90% control of female tick infestation, subsequent oviposition, and larval eclosion was obtained in those 8 of 16 sampled deer with serum ivermectin levels of ≥15 ng/ml. In addition, the ratio of females to males, the numbers of females engorging >10 mg body weight, and the numbers of those eventually hatching, were all significantly less among ticks from island deer in comparison with ticks from untreated deer. No consistent changes in the numbers of ticks found on immature-stage hosts or removed from vegetation were noted within 3 yr of the cessation of treatment.

Enzootic Babesia microti in Maine

Human babesiosis in the northeastern United States caused by Babesia microti (Apicomplexa: Piroplasmida) is mainly reported from coastal New England sites, where deer ticks (Ixodes dammini) are common. However, the piroplasm has been detected in microtine rodents elsewhere in association with I. angustus or other nidicolous ticks, suggesting that the agent is widely distributed but zoonotically significant only where a human-biting “bridge” vector is present. To determine whether this piroplasm may be enzootic in areas where I. dammini is absent, we surveyed small mammals collected from 2 sites in Maine, where I. angustus or I. muris is common but I. dammini is not. Of 43 chipmunks, voles, deer mice, and shrews examined, 3 (6.9, 95% confidence interval 0 to 14.5) were parasitemic, as determined by blood smear or polymerase chain reaction targeting a piroplasm-specific portion of the 18S ribosomal DNA gene. Phylogenetic analysis of the sequenced amplification products demonstrates the presence of 2 forms of B. microti. We conclude that B. microti may be enzootic in the absence of I. dammini but that human risk relates to dense infestations of this human-biting tick.