Katherine A. Feldman

Lyme Disease Testing by Large Commercial Laboratories in the United States

BACKGROUND Laboratory testing is helpful when evaluating patients with suspected Lyme disease (LD). A 2-tiered antibody testing approach is recommended, but single-tier and nonvalidated tests are also used. We conducted a survey of large commercial laboratories in the United States to assess laboratory practices. We used these data to estimate the cost of testing and number of infections among patients from whom specimens were submitted. METHODS Large commercial laboratories were asked to report the type and volume of testing conducted nationwide in 2008, as well as the percentage of positive tests for 4 LD-endemic states. The total direct cost of testing was calculated for each test type. These data and test-specific performance parameters available in published literature were used to estimate the number of infections among source patients. RESULTS Seven participating laboratories performed approximately 3.4 million LD tests on approximately 2.4 million specimens nationwide at an estimated cost of

Effectiveness of Residential Acaricides to Prevent Lyme and Other Tick-borne Diseases in Humans

492 million. Two-tiered testing accounted for at least 62% of assays performed; alternative testing accounted for <3% of assays. The estimated frequency of infection among patients from whom specimens were submitted ranged from 10% to 18.5%. Applied to the total numbers of specimens, this yielded an estimated 240 000 to 444 000 infected source patients in 2008. DISCUSSION LD testing is common and costly, with most testing in accordance with diagnostic recommendations. These results highlight the importance of considering clinical and exposure history when interpreting laboratory results for diagnostic and surveillance purposes.

Abundance and infection rates of Ixodes scapularis nymphs collected from residential properties in Lyme disease-endemic areas of Connecticut, Maryland, and New York

BACKGROUND In the northeastern United States, tick-borne diseases are a major public health concern. In controlled studies, a single springtime application of acaricide has been shown to kill 68%-100% of ticks. Although public health authorities recommend use of acaricides to control tick populations in yards, the effectiveness of these pesticides to prevent tick bites or human tick-borne diseases is unknown. METHODS We conducted a 2-year, randomized, double-blinded, placebo-controlled trial among 2727 households in 3 northeastern states. Households received a single springtime barrier application of bifenthrin or water according to recommended practices. Tick drags were conducted 3-4 weeks after treatment on 10% of properties. Information on human-tick encounters and tick-borne diseases was collected through monthly surveys; reports of illness were validated by medical record review. RESULTS Although the abundance of questing ticks was significantly lower (63%) on acaricide-treated properties, there was no difference between treatment groups in human-tick encounters, self-reported tick-borne diseases, or medical-record-validated tick-borne diseases. CONCLUSIONS Used as recommended, acaricide barrier sprays do not significantly reduce the household risk of tick exposure or incidence of tick-borne disease. Measures for preventing tick-borne diseases should be evaluated against human outcomes to confirm effectiveness.

Pet ownership increases human risk of encountering ticks

Ixodes scapularis, commonly known as the blacklegged tick, is responsible for transmitting Lyme disease (caused by Borrelia burgdorferi), the most common vector-borne disease in the United States (Centers for Disease Control and Prevention 2014). The blacklegged tick can also transmit Anaplasma phagocytophilum (the etiologic agent of human granulocytic anaplasmosis), Babesia microti (the causative agent of babesiosis), Borrelia miyamotoi (a relapsing fever Borrelia), and deer tick virus. In the northeastern U.S., the highest risk of exposure to the blacklegged tick is likely peridomestic, due to fragmented forest landscapes and other land-use characteristics, as well as the intrusion of humans into prime habitat for blacklegged ticks and their hosts (Falco and Fish 1988, Maupin et al. 1991, Nicholson and Mather 1996, Brownstein et al. 2005). Despite this, most reports of tick abundance and infection rates focus primarily on ticks collected from public lands and forested research sites (Aliota et al. 2014, Barbour et al. 2009, Diuk-Wasser et al. 2012, Hersh et al. 2014, Keesing et al. 2014).

Testing practices and volume of non-Lyme tickborne diseases in the United States

We examined whether pet ownership increased the risk for tick encounters and tickborne disease among residents of three Lyme disease‐endemic states as a nested cohort within a randomized controlled trial. Information about pet ownership, use of tick control for pets, property characteristics, tick encounters and human tickborne disease were captured through surveys, and associations were assessed using univariate and multivariable analyses. Pet‐owning households had 1.83 times the risk (95% CI = 1.53, 2.20) of finding ticks crawling on and 1.49 times the risk (95% CI = 1.20, 1.84) of finding ticks attached to household members compared to households without pets. This large evaluation of pet ownership, human tick encounters and tickborne diseases shows that pet owners, whether of cats or dogs, are at increased risk of encountering ticks and suggests that pet owners are at an increased risk of developing tickborne disease. Pet owners should be made aware of this risk and be reminded to conduct daily tick checks of all household members, including the pets, and to consult their veterinarian regarding effective tick control products.

Assessing diagnostic coding practices among a sample of healthcare facilities in Lyme disease endemic areas: Maryland and New York – A Brief Report

Large commercial laboratories in the United States were surveyed regarding the number of specimens tested for eight tickborne diseases in 2008. Seven large commercial laboratories reported testing a total of 2,927,881 specimens nationally (including Lyme disease). Of these, 495,585 specimens (17%) were tested for tickborne diseases other than Lyme disease. In addition to large commercial laboratories, another 1051 smaller commercial, hospital, and government laboratories in four states (CT, MD, MN, and NY) were surveyed regarding tickborne disease testing frequency, practices, and results. Ninety-two of these reported testing a total of 10,091 specimens for four tickborne diseases other than Lyme disease. We estimate the cost of laboratory diagnostic testing for non-Lyme disease tickborne diseases in 2008 to be

Exploring an alternative approach to Lyme disease surveillance in Maryland

9.6 million. These data provide a baseline to evaluate trends in tickborne disease test utilization and insight into the burden of these diseases.

Review of the Mid-Atlantic Tick Summit III: A model for regional information sharing.

The value of using diagnostic codes in Lyme disease (LD) surveillance in highly endemic states has not been well studied. Surveys of healthcare facilities in Maryland (MD) and New York (NY) regarding coding practices were conducted to evaluate the feasibility of using diagnostic codes as a potential method for LD surveillance. Most respondents indicated that their practice utilized electronic medical records (53%) and processed medical/billing claims electronically (74%). Most facilities were able to search office visits associated with specific ICD‐9‐CM and CPT codes (74% and 73%, respectively); no discernible differences existed between the healthcare facilities in both states. These codes were most commonly assigned by the practitioner (82%), and approximately 70% of respondents indicated that these codes were later validated by administrative staff. These results provide evidence for the possibility of using diagnostic codes in LD surveillance. However, the utility of these codes as an alternative to traditional LD surveillance requires further evaluation.

Impacts of misclassification on Lyme disease surveillance

In Maryland, Lyme disease (LD) is a reportable disease and all laboratories and healthcare providers are required to report to the local health department. Given the volume of LD reports and effort required for investigation, surveillance for LD is burdensome and subject to underreporting. We explored the utility of International Classification of Diseases, 9th Revision, Clinical Modification (administrative) codes for use with LD surveillance. We aimed to collect the administrative codes for a 10% sample of 2009 LD reports (n = 474) from 292 facilities stratified by case classification (confirmed, probable, suspected and not a case). Sixty‐three per cent (n = 184) of facilities responded to the survey, and 341 different administrative codes were obtained for 91% (n = 430) of sampled reports. The administrative code for Lyme disease (088.81) was the most commonly reported code (133/430 patients) among sampled reports; while it was used for 62 of 151 (41%) confirmed cases, it was also used for 48 of 192 (25%) not a case reports (sensitivity 41% and specificity 73%). A combination of nine codes was developed with sensitivity of 74% and specificity of 37% when compared to not a case reports. We conclude that the administrative code for LD alone has low ability to identify LD cases in Maryland. Grouping certain codes improved sensitivity, but our results indicate that administrative codes alone are not a viable surveillance alternative for a disease with complex manifestations such as LD.

Lyme disease surveillance in the United States: Looking for ways to cut the Gordian knot

Ticks are the most significant vectors of infectious diseases in the United States, inspiring many researchers to study aspects of their biology, ecology, and their effects on public health. However, regional differences in tick abundance and pathogen infection prevalence result in the inability to assume results from one area are relevant in another. Current local information on tick ranges, infection rates, and human cases is needed to assess tick-borne disease risk in any given region. The Mid-Atlantic Tick Summit III brought together over 100 area experts and researchers to share regional updates on ticks and their associated pathogens. We report some meeting highlights here. Regional meetings foster cross-disciplinary collaborations that benefit the community, and open novel lines of inquiry so that tick-bite risk can be reduced and tick-borne diseases can be treated effectively.