Serologic surveillance for the Lyme disease spirochete, Borrelia burgdorferi, in Minnesota by using white-tailed deer as sentinel animals

A framework for adaptive surveillance of emerging tick-borne zoonoses

Significant global ecological changes continue to drive emergence of tick-borne zoonoses around the world. This poses an important threat to both human and animal health, and highlights the need for surveillance systems that are capable of monitoring these complex diseases effectively across different stages of the emergence process. Our objective was to develop an evidence-based framework for surveillance of emerging tick-borne zoonoses. We conducted a realist review to understand the available approaches and major challenges associated with surveillance of emerging tick-borne zoonoses. Lyme disease, with a specific focus on emergence in Canada, was used as a case study to provide real-world context, since the process of disease emergence is ongoing in this country. We synthesize the results to propose a novel framework for adaptive surveillance of emerging tick-borne zoonoses. Goals for each phase of disease emergence are highlighted and approaches are suggested. The framework emphasizes the needs for surveillance systems to be inclusive, standardized, comprehensive and sustainable. We build upon a growing body of infectious disease literature that is advocating for reform to surveillance systems. Although our framework has been developed for tick-borne zoonoses, it is flexible and has the potential to be applied to a variety of other vector-borne and zoonotic diseases.

Seroprevalence of Borrelia burgdorferi antibodies in white-tailed deer from Texas

Lyme Disease is caused by the bacterial pathogen Borrelia burgdorferi, and is transmitted by the tick-vector Ixodes scapularis. It is the most prevalent arthropod-borne disease in the United States. To determine the seroprevalence of B. burgdorferi antibodies in white-tailed deer (Odocoileus virginianus) from Texas, we analyzed serum samples (n = 1493) collected during the 2001–2015 hunting seasons, using indirect ELISA. Samples with higher sero-reactivity (0.803 and above) than the negative control group (0.662) were further tested using a more specific standardized western immunoblot assay to rule out false positives. Using ELISA, 4.7% of the samples were sero-reactive against B. burgdorferi, and these originated in two eco-regions in Texas (Edwards Plateau and South Texas Plains). However, only 0.5% of the total samples were sero-reactive by standardized western immunoblot assay. Additionally, both ELISA and standardized western immunoblot assay results correlated with an increased incidence in human Lyme Disease cases reported in Texas. This is the first longitudinal study to demonstrate fluctuation in sero-reactivity of white-tailed deer to B. burgdorferi sensu stricto antigens in southern United States. Future ecological and geographical studies are needed to assess the environmental factors governing the prevalence of Lyme Disease in non-endemic areas of the southern United States.

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White-tailed deer serum samples were analyzed for anti Borrelia burgdorferi IgG.

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This is the first 15-year longitudinal study reported in Texas, and provides data previously unavailable within the study of Lyme disease ecology.

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White-tailed deer population density might be critical to sero-prevalence.

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Further pathogenic landscape studies on Lyme disease in Texas are recommended.

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Databased Lyme disease ecology models in Texas can be developed.

The use of deer vehicle accidents as a proxy for measuring the degree of interaction between human and deer populations and its correlation with the incidence rate of Lyme disease

The study described in this article examined the relationship between the incidence rate of deer vehicle accidents (DVAs), a proxy for measuring the interaction between populations of humans and deer, and human Lyme disease incidence rate. The authors also examined the relationship between deer population density and human Lyme incidence rate. They analyzed data from Connecticut's Department of Environmental Protection and the Department of Public Health from 1999 through 2008 by deer management zone (DMZ) and town. For DVA incidence rate versus Lyme incidence rate for both DMZs and towns, most of the correlation coefficients computed yearly were moderate to strong and all of the p-values were significant. A weak correlation was observed between deer population density and Lyme disease incidence rate by DMZ. The authors propose DVAs as a proxy for measuring the interaction between coexisting populations of humans and deer. The authors' study suggests that additional investigations of DVAs and their relationship to Lyme disease to further assess the utility of public health interventions are warranted.

Distribution of antibodies reactive to Borrelia lonestari and Borrelia burgdorferi in white-tailed deer (Odocoileus virginianus) populations in the eastern United States

Southern tick-associated rash illness is a Lyme-like syndrome that occurs in the southern states. Borrelia lonestari, which has been suggested as a possible causative agent of southern tick-associated rash illness, naturally infects white-tailed deer (WTD; Odocoileus virginianus) and is transmitted by the lone star tick (Amblyomma americanum). To better understand the prevalence and distribution of Borrelia exposure among WTD, we tested WTD from 21 eastern states for antibodies reactive to B. lonestari using an indirect immunofluorescent antibody assay and Borrelia burgdorferi using the IDEXX SNAP 4Dx test. A total of 107/714 (15%) had antibodies reactive to B. lonestari, and prevalence of antibodies was higher in deer from southern states (17.5%) than in deer from northern states (9.2%). Using the SNAP 4DX test, we found that 73/723 (10%) were positive for B. burgdorferi, and significantly more northern deer (23.9%) were positive compared with southern deer (3.8%). Our data demonstrate that WTD are exposed to both Borrelia species, but antibody prevalence for exposure to the two species differs regionally and distributions correlate with the presence of Ixodes scapularis and A. americanum ticks.

Serosurveillance forAnaplasma phagocytophilumAntibodies in White-Tailed Deer (Odocoileus virginianus) in Iowa, USA

Cases of human granulocytic anaplasmosis have increased in number and are being identified in new geographic areas since its discovery in 1994. White-tailed deer (WTD) become infected with the causative agent, Anaplasma phagocytophilum, and serve as natural sentinels for this organism. In order to determine if A. phagocytophilum is present in the state of Iowa, sera collected from 628 WTD in 2004 from 13 sites and from 282 WTD in 1999 from a single, common site were tested by enzyme-linked immunosorbent assay and Western immunoblotting. A seroprevalence of 9.1% was found among the 2004 samples, and there was no change in seropositivity rates from 1999 to 2004 at the single, common site. As A. phagocytophilum is another tick-borne human pathogen to be identified in the state of Iowa, this study has important implications for health care providers.

Canines as sentinels for Lyme disease in San Diego County, California

Prevalence of Lyme borreliosis in canine sentinels has been shown to correlate with infection in humans. One thousand canine sera (917 dogs, 83 coyotes) obtained from animal control authorities and area veterinarians were screened by ELISA for antibodies to Borrelia burgdorferi. Results were validated by Western blot and indirect fluorescent antibody (IFA) tests at referee laboratories. Criterion for a positive Western blot was presence of 5 of 10 of the most common antigen IgG bands; for IFA, >1:128 or the equivalent when correcting for interlaboratory variability. Twenty-two of 1,000 canines were confirmed serologically positive (21 dogs and 1 coyote; seroprevalence 2.3% and 1.2%, respectively). Lifestyle, breed size, gender, and age were not statistically predictive of seropositive status. No regional clustering of seropositive animals was detected. The low prevalence of seropositivity in sentinel canines suggests the Lyme borreliosis hazard in San Diego County is minimal.

Borrelioses, agentes e vetores

As borrelioses são enfermidades infecciosas determinadas por espiroquetas do gênero Borrelia, agentes transmissíveis, principalmente, por carrapatos aos animais e/ou ao homem. Nesta revisão são apresentadas e discutidas as enfermidades determinadas por borrélias, bem como as características gerais das espiroquetas, os aspectos relacionados a transmissão por artrópodes, as enfermidades nos animais domésticos e silvestres, quanto aos aspectos biológicos e patológicos, a doença de Lyme como principal zoonose do grupo, a associação de borrélia com outros agentes hematozoários e os métodos diagnósticos e a epidemiologia comparativa entre dados obtidos no Brasil com os de outros países. Estas borrelioses possuem características patológicas, clínicas e epidemiológicas variadas de acordo à região fisiográfica, devido à existência de distintas espécies, genoespécies e cepas; estes aspectos variam ainda em função dos artrópodes vetores, da interação vetor-patógeno e dos ecossistemas distintos.

Borrelia burgdorferi sensu lato in an endemic environment: wild sika deer (Cervus nippon yesoensis) with infected ticks and antibodies

Ticks and blood samples were collected from wild sika deer (Cervus nippon yesoensis) during a hunting season (August to October) of 1991 at a selected location in Hokkaido, Japan. Ixodes persulcatus (adult and nymph) and I. ovatus (adult) were the common ticks on sika deer. Spirochetes were detected in the midgut of the ticks by the indirect peroxidase-conjugated antibody staining method and by dark-field microscopy after cultivation. By the reactive pattern of monoclonal antibodies, isolates were considered to belong to Borrelia garinii or B. japonica. In an antibody test, the percentage of seropositive deer was 69.0%. Most of the adult sika deer were positive for antibodies to the spirochetes. There are significant age-dependency in antibody level and seropositive rate. The surveillance of deer should be valuable in monitoring the transmission risk of B. burgdorferi sensu lato in nature.

Antibody response of the mouse reservoir of Borrelia burgdorferi in nature

To determine whether the white-footed mouse reservoir host (Peromyscus leucopus) of the agent of Lyme disease (Borrelia burgdorferi) naturally mounts an immune response against the full range of antigens expressed by this zoonotic pathogen, we analyzed the pattern of immunoreactivity of these rodents at sites in which the intensity of transmission differs. Although the incidence of seroconversion within the reservoir population relates proportionally to the density of subadult deer ticks (Ixodes dammini), seroprevalence appears constant. About a fifth as many juvenile mice recognize spirachete antigens as do adult mice. Virtually all reservoir mice in nature recognize the p20, p35.5, p39, and p58 antigens, regardless of the intensity of transmission. Seropositive mice retain reactivity to a wide range of spirochetal antigens. Few mice recognize flagellin, OspB, and OspC. Although a third of serum samples include reactivity to a 31-kDa band, this reaction is irregular and may represent an uncharacterized antigen that comigrates with OspA. Mice captured where transmission is intense recognize the same spectrum of antigens as do mice captured where vector ticks are scarce.

Borrelia burgdorferi in an urban environment: white-tailed deer with infected ticks and antibodies

Ticks and blood samples were collected from white-tailed deer (Odocoileus virginianus) in forests located in an insular, urban area of Bridgeport, Conn., and in rural south central Connecticut during 1992 and 1993. Immature and adult Ixodes scapularis ticks were tested for Borrelia burgdorferi, the etiologic agent of Lyme borreliosis, by indirect fluorescent-antibody staining methods. Deer sera were analyzed for antibodies to this bacterium by an enzyme-linked immunosorbent assay. Infected ticks parasitized deer in Bridgeport from May through December; the prevalence of infection varied from 1.1% of 93 larvae to 28.1% of 114 adult females. The percentages of infected males (10.5% of 380 ticks) and females (13.7% of 328 ticks) were relatively lower in south central Connecticut. In antibody tests, the prevalence of seropositive specimens collected in Bridgeport (61% of 146 serum specimens) was more than twofold greater than that of specimens obtained in south central Connecticut (26.7% of 116 serum specimens). Foci for Lyme borreliosis can occur in forested, urban settings as well as in rural areas if there are ticks, rodents, birds, and large mammals present. Human exposure to ticks in such sites should be considered as a possible source of B. burgdorferi infection.