Lyme Disease Teaching/Information Booklet – By John Scott – Printable
Lyme Ontario Research Current Research
Lyme Ontario Research
The Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.), is typically transmitted to mammalian hosts, including humans, by ixodid (hard-bodied) ticks (Acari: Ixodidae) [1]. Each tick species has its own set of suitable hosts, and Lyme disease, a zoonosis, is incidental to humans and domestic animals [2,3]. Left untreated or inadequately treated, Lyme disease can inflict a myriad of multisystemic clinical manifestations. We document the presence of blacklegged ticks, Ixodes scapularis, in the Grand River valley, Centre Wellington, Ontario. Overall, 15 (36%) of 42 I. scapularis adults collected from 41 mammalian hosts (dogs, cats, humans) were positive for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.). Using real-time PCR testing and DNA sequencing of the flagellin (fla) gene, we determined that Borrelia amplicons extracted from I. scapularis adults belonged to B. burgdorferi sensu stricto (s.s.), which is pathogenic to humans and certain domestic animals. Based on the distribution of I. scapularis adults within the river basin, it appears likely that migratory birds provide an annual influx of I. scapularis immatures during northward spring migration. Health-care providers need to be aware that local residents can present with Lyme disease symptoms anytime during the year. The blacklegged tick, Ixodes scapularis has an established population at Point Pelee National Park (PPNP). We document an established population of blacklegged ticks, Ixodes scapularis, on Corkscrew Island, Kenora District, Ontario, Canada. Primers of the outer surface protein A (OspA) gene, the flagellin (fla) gene, and the flagellin B (flaB) gene were used in the PCR assays to detect Borrelia burgdorferi sensu lato (s.l.), the Lyme disease bacterium. In all, 60 (73%) of 82 adult I. scapularis, were infected with B. burgdorferi s.l. As well, 6 (43%) of 14 unfed I. scapularis nymphs were positive for B. burgdorferi s.l. An I. scapularis larva was also collected from a deer mouse, and several unfed larvae were gathered by flagging leaf litter. Based on DNA sequencing of randomly selected Borrelia amplicons from six nymphal and adult I. scapularis ticks, primers for the flagellin (fla) and flagellin B (flaB) genes reveal the presence of B. burgdorferi sensu stricto (s.s.), a genospecies pathogenic to humans and certain domestic animals. We collected all 3 host-feeding life stages of I. scapularis in a single year, and report the northernmost established population of I. scapularis in Ontario. Corkscrew Island is hyperendemic for Lyme disease and has the highest prevalence of B. burgdorferi s.l. for any established population in Canada. Because of this very high infection prevalence, this population of I. scapularis has likely been established for decades. Of epidemiological significance, cottage owners, island visitors, outdoors enthusiasts, and medical professionals must be vigilant that B. burgdorferi s.l.-infected I. scapularis on Corkscrew Island pose a serious public health risk. Migratory songbirds transport hard-bodied ticks (Acari: Ixodidae) into Canada during northward spring migration, and some of these bird-feeding ticks harbor a wide diversity of pathogenic microorganisms. In this study, we collected a nymphal Ixodes affinis Neumann from a Common Yellowthroat, Geothylypis trichas (Linnaeus), at Ste-Anne-de-Bellevue, Québec, and it was infected with the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) Johnson, Schmid, Hyde, Steigerwalt & Brenner. Using PCR on this tick extract and DNA sequencing on the borrelial amplicons, we detected B. burgdorferi sensu stricto (s.s.), a genospecies that is pathogenic to people and certain domestic animals. In addition, we collected an I. affinis nymph from a Swainson’s Thrush, Catharus ustulatus (Nuttall), at Toronto, Ontario, and a co-feeding nymphal blacklegged tick, Ixodes scapularis Say, tested positive for B. burgdorferi s.s. These bird-tick findings constitute the first reports of I. affinis in Ontario and Québec and, simultaneously, the first report of a B. burgdorferi s.l.-infected I. affinis in Canada. Since Neotropical and southern temperate songbirds have a rapid flight pace, they are capable of transporting ticks infected with B. burgdorferi s.l. hundreds of kilometres to Canada. Healthcare professionals should be cognisant that migratory songbirds can transport diverse genotypes of B. burgdorferi s.l. into Canada from southern latitudes that may be missed by current Lyme disease serological tests. We document the first record of Borrelia americana in Canada. This Borrelia was detected in an avian coast tick, Ixodes auritulus (Acari: Ixodidae), collected from a Varied Thrush, Ixoreus naevius, along coastal British Columbia. Using real-time PCR and DNA sequencing of the flagellin gene, we determined that the borrelial amplicon from the I. auritulus nymph was 99% homologous with B. americana type strain SCW-41. Because patients infected with B. americana can be seronegative for Lyme disease, medical professionals should be willing to pursue molecular analyses and con-ider treatment for patients with Lyme disease-like symptoms. Bobbi Pritt and colleagues1 reveal that Borrelia mayonii is a new member of the Borrelia burgdorferi sensu lato complex, and show that this spirochete is pathogenic to human beings. However, the authors err on several key points. They state B burgdorferi sensu stricto was previously the only cause of Lyme borreliosis in the USA. With the discovery of B mayonii, they take credit for describing the first non-B burgdorferi sensu stricto in patients in the USA; this assumption is not true. Girard and colleagues2 reported B bissettii in patients in California and Clark and colleagues3 documented B americana and B andersonii in human blood from resi dents in the southeastern USA. Further more, Rudenko and colleagues4 reported a B bissettiilike strain in a Florida patient. In all of these cases, patients had clinical symptoms commonly associated with Lyme borreliosis. Lyme disease has emerged as a major health concern in Canada, where the etiological agent, Borrelia burgdorferi sensu lato (s.l.), a spirochetal bacterium, is typically spread by the bite of certain ticks. This study explores the presence of B. burgdorferi s.l. in blacklegged ticks, Ixodes scapularis, collected at Dundas, Ontario (a locality within the region of Hamilton-Wentworth). Using passive surveillance, veterinarians and pet groomers were asked to collect blacklegged ticks from dogs and cats with no history of travel. Additionally, I. scapularis specimens were submitted from local residents and collected by flagging. Overall, 12 (41%) of 29 blacklegged ticks were infected with B. burgdorferi s.l. Using polymerase chain reaction (PCR) and DNA sequencing, two borrelial amplicons were characterized as B. burgdorferi sensu stricto (s.s.), a genospecies pathogenic to humans and certain domestic animals. Notably, three different vertebrate hosts each had two engorged I. scapularis females removed on the same day and, likewise, one cat had three repeat occurrences of this tick species. These multiple infestations suggest that a population of I. scapularis may be established in this area. The local public health unit has been underreporting the presence of B. burgdorferi s.l.-infected I. scapularis in the area encompassing Dundas. Our findings raise concerns about the need to erect tick warning signs in parkland areas. Veterinarians, medical professionals, public health officials, and the general public must be vigilant that Lyme disease-carrying blacklegged ticks pose a public health risk in the Dundas area and the surrounding Hamilton-Wentworth region. In far-western Canada, gallinaceous birds are hosts of hard ticks (Ixodida: Ixodidae) that can carry zoonotic pathogens. In this study, we collected the avian coastal tick, Ixodes auritulus Neumann, the western blacklegged tick, Ixodes pacificus Cooley & Kohls, and Ixodes spinipalpis Hadwen & Nuttall, from gallinaceous birds on Vancouver Island, British Columbia. Notably, we provide the first records of these three tick species on California Quail, Callipepla californica (Shaw), in Canada. We document the first records of I. auritulus parasitizing Sooty Grouse, Dendragapus fulginosis (Ridway). Moreover, we furnish the first report of I. spinipalpis on a quail. An I. pacificus nymph was collected from a California Quail, and it was positive for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) Johnson, Schmid, Hyde, Steigerwalt & Brenner. Using PCR on the nymphal extract and DNA sequencing on the borrelial amplicon, we specifically detected B. burgdorferi sensu stricto (s.s.), a genospecies pathogenic to humans and certain domestic animals. Since some ground-dwelling birds are involved in the enzootic maintenance of Lyme disease, veterinarians, wildlife rehabilitators, hunters, and health-care providers should be vigilant that gallinaceous birds may play a role in the enzootic transmission of B. burgdorferi s.l. in Canada. We document Amblyomma dissimile Koch (Acari: Ixodidae) parasitizing a bird in Canada. A partially engorged A. dissimile nymph was collected from a Veery, Catharus fuscescens (Stephens) (Passeriformes: Turdidae), in Toronto, Ontario during spring migration. This constitutes the first authentic host record of A. dissimile on a bird in North America and, likewise, on a Veery, plus a new distributional record in Canada. Veeries could theoretically transport A. dissimile from as far south as southeastern Brazil, a distance of over 7,500 km. Experimentally, A. dissimile can transmit Ehrlichia ruminantium (Ricksettiales), which causes heartwater, a severe disease of cattle and other ungulates. Since a fully engorged A. dissimile nymph could likely molt during the summer in northern latitudes, this tick species could potentially parasitize local reptiles, people or ungulates, and cause autochtonous disease. Because A. dissimile is known to harbor rickettsiae in South America and is a laboratory vector of E. ruminantium, the medical and veterinary profession must be vigilant that A. dissimile may pose a health risk. Migratory birds disperse engorged ticks across Canada during northward spring migration. During our tick-host study, we collected a nymphal Amblyomma rotundatum Koch, from a Veery, Catharus fuscescens (Stephens) (Passeriformes: Turdidae), at Long Point, Ontario, Canada. In the laboratory, this nymph molted to a female in 44 d. The infestation of A. rotundatum on a Veery constitutes a first tick-host record, and a new distributional record in Canada. Notably, this novel collection is the northernmost record of A. rotundatum and the first record of this species on a bird anywhere. We provide formidable evidence that migratory songbirds can carry A. rotundatum thousands of kilometers during northward spring migration. From an epidemiological perspective, A. rotundatum is known to harbor bacteria that are pathogenic to humans. Health-care providers should take note that migratory songbirds can transport A. rotundatum into Canada, and be alert that this tick species signifies an unforeseen public health risk to humans. This study highlights the collection of ticks from wild-caught birds in central and eastern Canada. Using polymerase chain reaction (PCR), 32 (33%) of 98 Ixodes species ticks tested were positive for the Lyme disease bacterium, Borrelia burgdorferi sensu lato (s.l.) Johnson, Schmid, Hyde, Steigerwalt, and Brenner (hereafter B. burgdorferi). Immature blacklegged ticks, Ixodes scapularis Say, which are competent vectors of B. burgdorferi, constituted the predominant Ixodes species tick collected from parasitized songbirds; specifically, 31(35%) of 89 I. scapularis nymphs were positive for B. burgdorferi. Notably, we report the first B. burgdorferi-positive I. scapularis (nymph) on a migratory passerine in Prince Edward Island; this is the first record of a tick on a bird in this maritime province. Worldwide, wild birds play a vital role in the dispersal of ticks that harbour tick-borne pathogens, including Borrelia burgdorferi, the Lyme disease bacterium. Using PCR testing, we found 124 (31%) of 405 ticks (4 species), which were collected from 21 species of birds in far-western Canada, to be infected with B. burgdorferi. Transstadial transmission of B. burgdorferi occurred from larva to nymph, plus nymph to adult, in the avian coastal tick, Ixodes auritulus, collected from songbirds in British Columbia (B.C). Collectively, all 3 motile life stages (larva, nymph, adult) of this tick had an infection prevalence of 31% for B. burgdorferi, which suggests vector competency. A Pacific Wren was highly infested with I. auritulus immatures, and 20 (44%) of 45 ticks (2 nymphs, 43 larvae) were infected with B. burgdorferi. This heavy infestation shows the high potential to initiate a new population of ticks and to disseminate Lyme spirochetes. Epidemiologically, B. burgdorferi-in- fected I. auritulus larvae collected from the Spotted Towhee, Swainson’s Thrush, Pacific Wren, and Fox Sparrow suggest that these avian hosts act as reservoirs for B. burgdorferi. In this study, the western blacklegged tick, Ixodes pacificus, and Ixodes spinipalpis played a limited role in the enzo- otic transmission cycle of B. burgdorferi along coastal B.C. We document the first record of I. spinipalpis on a bird in Alberta. Because songbirds widely disperse Lyme disease vector ticks, primary health providers and the general public must be vigilant that outdoors people may be bitten by B. burgdorferi-infected ticks throughout far-western Canada. This 2-year study implicates migratory songbirds in the initiation of an inland Lyme disease endemic area in southeastern Ontario. The spirochetal bacterium, Borrelia burgdorferi sensu lato Johnson, Schmid, Hyde, Steigerwalt & Brenner, which causes Lyme disease, was detected in blacklegged ticks, Ixodes scapularis Say, collected by flagging. Based on PCR amplification, 19 (33.3%) of 57 I. scapularis adults (males, females) were infected with B. burgdorferi. Since transovarial transmission of B. burgdorferi is nil in I. scapularis and white-tailed deer, Odocoileus virginianus Zimmermann, are not reservoircompetent hosts, we suggest that songbirds are the mode of introduction of B. burgdorferi-infected I. scapularis. All of the natural abiotic and biotic attributes are present to establish a Lyme disease endemic area. Blacklegged ticks survived the winter successfully at the epicentre. We provide substantial evidence that migratory songbirds initially introduced Lyme disease vector ticks and B. burgdorferi spirochetes to this remote woodland habitat and initiated an established population of blacklegged ticks. During a pan-Canadian tick-host study, we detected the spirochetal bacterium, Borrelia burgdorferi sensu lato, which causes Lyme disease, in ticks collected from a raptor. Lyme disease is one of a number of zoonotic, tick-borne diseases causing morbidity and mortality worldwide. Larvae of the avian coastal tick, Ixodes auritulus, were collected by wildlife rehabilitators from a Cooper’s hawk, Accipiter ooperii, on Vancouver Island, British Columbia. Using PCR amplification of the linear plasmid ospA gene of B. burgdorferi, 4 (18%) of 22 larvae were positive. Since these engorged I. auritulus larvae had not had a previous blood meal and B. burgdorferi is rarely transmitted from infected female ticks to their progeny, we propose that Cooper’s Hawks are reservoir-competent hosts of B. burgdorferi. Our tick-host discovery provides the first report of bird-feeding ticks on a Cooper’s Hawk, and exhibits the premiere record of B. burgdorferi-positive ticks on a raptor. Not only are passerine (perching) and gallinaceous (chicken-like) birds involved in the wide dispersal of Lyme disease vector ticks, raptors are now also implicated in the dissemination of B. burgdorferiinfected ticks. Although I. auritulus does not bite humans, this tick species plays an integral role in the 4-tick enzootic cycle of B. burgdorferi along the West Coast of North America. In essence, raptors and I. auritulus ticks may help to amplify this infectious agent in nature, and increase the likelihood of people contracting Lyme disease, especially in coastal areas. Millions of Lyme disease vector ticks are dispersed annually by songbirds across Canada, but often overlooked as the source of infection. For clarity on vector distribution, we sampled 481 ticks (12 species and 3 undetermined ticks) from 211 songbirds (42 species/subspecies) nationwide. Using PCR, 52 (29.5%) of 176 Ixodes ticks tested were positive for the Lyme disease spirochete, Borrelia burgdorferis.l. Immature blacklegged ticks,Ixodes scapularis, collected from infested songbirds had a B. burgdorferi infection prevalence of 36% (larvae, 48%; nymphs, 31%). Notably, Ixodes affinis is reported in Canada for the first time and, similarly, Ixodes auritulus for the initial time in the Yukon. Firsts for bird-parasitizing ticks include I. scapularis in Quebec and Saskatchewan. We provide the first records of 3 tick species cofeeding on passerines (song sparrow, Swainson’s thrush). New host records reveal I. scapularis on the blackpoll warbler and Nashville warbler. We furnish the following first Canadian reports of B. burgdorferi–positive ticks: I. scapularis on chipping sparrow, house wren, indigo bunting; I. auritulus on Bewick’s wren; and I. spinipalpis on a Bewick’s wren and song sparrow. First records of B. burgdorferi–infected ticks on songbirds include the following: the rabbit-associated tick, Ixodes dentatus, in western Canada; I. scapularis in Quebec, Saskatchewan, northern New Brunswick, northern Ontario; and Ixodes spinipalpis(collected in British Columbia). The presence ofB. burgdorferi in Ixodeslarvae suggests reservoir competency in 9 passerines (Bewick’s wren, common yellowthroat, dark-eyed junco, Oregon junco, red-winged blackbird, song sparrow, Swainson’s thrush, swamp sparrow, and white-throated sparrow). We report transstadial transmission (larva to nymph) of B. burgdorferi in I. auritulus. Data suggest a possible 4-tick, i.e.,I. angustus,I. auritulus,I. pacificus, and I. spinipalpis, enzootic cycle ofB. burgdorferi on Vancouver Island, British Columbia. Our results suggest that songbirds infested with B. burgdorferi–infected ticks have the potential to start new tick populations endemic for Lyme disease. Because songbirds disperse B. burgdorferi–infected ticks outside their anticipated range, health-care providers are advised that people can contract Lyme disease locally without any history of travel. Lyme disease is reported across Canada, but pinpointing the source of infection has been problematic. In this three-year, bird-tick-pathogen study (2004-2006), 366 ticks representing 12 species were collected from 151 songbirds (31 passerine species/subspecies) at 16 locations Canada-wide. Of the 167 ticks/pools tested, 19 (11.4%) were infected with Borrelia burgdorferi sensu lato (s.l.). Sequencing of the rrf-rrl intergenic spacer gene revealed four Borrelia genotypes: B. burgdorferi sensu stricto (s.s.) and three novel genotypes (BC genotype 1, BC genotype 2, BC genotype 3). All four genotypes were detected in spirochete-infected Ixodes auritulus (females, nymphs, larvae) suggesting this tick species is a vector for B. burgdorferi s.l. We provide first-time records for: ticks in the Yukon (north of 60° latitude), northernmost collection of Amblyomma americanum in North America, and Amblyomma imitator in Canada. First reports of bird-derived ticks infected with B. burgdorferi s.l. include: live culture of spirochetes from Ixodes pacificus (nymph) plus detection in I. auritulus nymphs, Ixodes scapularis in New Brunswick, and an I. scapularis larva in Canada. We provide the first account of B. burgdorferi s. l. in an Ixodes muris tick collected from a songbird anywhere. Congruent with previous data for the American Robin, we suggest that the Common Yellowthroat, Golden-crowned Sparrow, Song Sparrow, and Swainson’s Thrush are reservoir-competent hosts. Song Sparrows, the predominant hosts, were parasitized by I. auritulus harboring all four Borrelia genotypes. Our results show that songbirds import B. burgdorferi s.l.-infected ticks into Canada. Bird-feeding I. scapularis subadults were infected with Lyme spirochetes during both spring and fall migration in eastern Canada. Because songbirds disperse millions of infected ticks across Canada, people and domestic animals contract Lyme disease outside of the known and expected range. Borrelia burgdorferi sensu stricto (s.s.) was isolated from questing adult Ixodes scapularis Say ticks collected from Turkey Point Provincial Park (TPPP), Ontario, Canada during 2005-2006. DNA from ten (67%) of 15 pools of ticks was confirmed positive for B. burgdorferi s.s. using polymerase chain reaction (PCR) by targeting the rrf (5S)-rrl (23S) intergenic spacer region and OspA genes. This significant infection rate indicates an accelerated development of B. burgdorferi s.s. in TPPP, because this pathogen was not detected five years previously during sampling of the three motile life stages of I. Over the past two decades, Ixodes scapularis, the primary tick vector of the Lyme disease pathogen Borrelia burgdorferi in North America has expanded its range northward from the USA to colonize new regions in southern Canada. We have previously projected range increases for I. scapularis based on temperature suitability, but to what extent this is matched by actual tick range expansion is unknown.
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scapularis. Our study provides the initial report of the presence of B. burgdorferi s.s. in TPPP, which is now endemic for Lyme disease. Ultimately, people and domestic animals are at risk of contracting Lyme disease when they frequent this park.
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alphabetically and chronologically:
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