Internsrional Journolfor Printed in Grear Britain
Parasitology
I
002&75l9/9l $3.00 + 0.00 Pergamon Press p/c Ausrralian Society for Parasitology
Vol. 21, No. I, pp. ICY&l I. 1991
RESEARCHNOTE VECTOR COMPETENCE OF THE AUSTRALIAN PARALYSIS TICK, IXODES HOLOCYCLUS, FOR THE LYME DISEASE SPIROCHETE BORRELIA BURGDORFERI JOSEPH PIESMAN* and BERNARD F. SToNEt * Division of Vector-borne Infectious Diseases, Center for Infectious Diseases, Centers for Disease Control, Public Health Service, U.S. Department of Health and Human Services, P. 0. Box 2087, Ft Collins, CO 80522, U.S.A. t Division of Tropical Animal Production, Long Pocket Laboratories, CSIRO, Private Bag No. 3, Indooroopilly, Queensland 4068, Australia (Received 19 July 1990; accepted 18 September 1990)
Abstract-PlasMAN J. and STONEB. F. 1991. Vector competence of the Australian paralysis tick, Ixodes Parasitology 21: 109-l 11. Clinical and serologic evidence of Lyme disease in Australia, including the typical rash, erythema migrans, has been reported. The vector tick transmitting Borreliu burgdorferi in Australia, however, has not been determined. The Australian paralysis tick, Zxodes holocycfus,is a logical candidate vector of the Lyme disease spirochete in Australia; therefore, we tested the ability of I. holocyclus to acquire and maintain a North American isolate of B. burgdorferi. Larval I. holocyclus ingested spirochetes, but none of 84 derived nymphs were infected. These experiments should be repeated with Australian strains of spirochetes. holocyclw, for the Lyme disease spirochete Borrelia burgdorferi. International Journalfor
INDEX KEY WORDS: Borrelia burgdorferi; paralysis tick; Ixodes holocyclus.
Lyme disease; vector competence;
LYME disease has recently become a public health concern of global importance. The majority of welldocumented human infections with the Lyme disease spirochete, Borrelia burgdorferi, have occurred in Europe and North America where thousands of cases have been reported (Stanek, Pletschette, Flamm, Hirschl, Aberer, Kristoferitsch & Schmutzhard, 1988; Ciesielski, Markowitz, Horsley, Hightower, Russell & Broome, 1989; Centers for Disease Control, 1989). Moreover, Lyme disease appears to be endemic in temperate areas of Asia, including parts of the Soviet Union (Korenberg, Kryuchechnikov, Ananyina & Chernukha, 1986), China (Ai, Wen, Zhang, Wang, Qiu, Shi, Li, Chen, Liu & Zhao, 1988), and Japan (Kawabata, Baba, Iguchi, Yumaguti & Russell, 1987). Isolated instances of human sera containing presumptive antibodies to B. burgdorferi have been reported from Africa (Haberberger, Constantine, Schwan &Woody, 1989). In Australia, seven cases of erythema migrans (EM), the typical rash associated with Lyme disease, were originally reported from the Hunter Valley, north of Sydney, New South Wales (Stewart, Glass, Patel, Watt, Cripps & Clancy, 1982). Additional cases of EM were discovered in New South Wales (McCrossin, 1986; Lawrence, Bradbury & Cullen, 1986), and in Queensland, serologic evidence of infection with B. burgdorferi was reported in 30 patients with arthritis (Stallman, 1987). Also, Munro
ticks; Australian
& Dickeson (1989) identified 11 seroreactive persons with a variety of symptoms who apparently acquired Lyme disease in Australia. The principal tick vectors of Lyme disease around the world are members of the Ixodes ricinus ‘complex’, which includes I. dammini, I. scapularis, I. paciJicus, I. ricinus and I. persulcatus (see Burgdorfer, Hayes & Corwin, 1989; Anderson, 1989). Another member of the genus, I. dentutus, the rabbit tick, has also been shown (Anderson, Magnarelli, Lefebvre, Andreadis, McAninch, Pemg & Johnson, 1989; Telford & Spielman, 1989) to be a competent vector of B. burgdorferi. No member of the I. ricinus ‘complex’ is extant in Australia; however, the Australian paralysis tick, I. holocyclus, is widespread. This tick species feeds predominantly on bandicoots (Stone, 1988), but frequently attacks people and domestic animals (Stone, Gauci & Thong, 1987). If Lyme disease exists in Australia, I. holocyclus would be a logical candidate vector. Accordingly, we tested the vector competence of I. holocyclus for B. burgdorferi Vector competence trials were conducted as previously described (Piesman & Sinsky, 1988; Piesman, 1988). Briefly, female hamsters (SO-150 g) were infected by allowing 10-12 nymphal I. dammini infected with the JDl strain of B. burgdorferi to feed on them. The JDl strain of B. burgdorferi was isolated from I. dammini in Ipswich, MA, U.S.A. and was maintained as previously described (Piesman,
109
110
J. PIE~SMAN and B. F. STONE
Mather, Sinsky & Spielman, 1987). At 1 month postexposure, larval I. holocyclus and I. dammini were fed to repletion on these infected hamsters. Midgut pre-
parations from larvae were subsequently examined for spirochetes by darkfield and direct fluorescent antibody microscopy (Piesman, Mather, Telford & Spielman, 1987). The colony of I. &mini used in these experiments was derived from females collected on Great Island, MA, U.S.A., and maintained with no evidence of transovarial generations.
spirochete transmission during The 1. holocyclus were obtained
three
from the CSIRO Long Pocket Laboratory colony, originally derived from ticks collected in southeastern Queensland and northern New South Wales. All ticks were maintained at 21°C and 97% RH. Ticks were examined for spirochetes on days 5, 15, and >45 post-larval feeding. The ticks examined after day 45 had molted to nymphs. The larval I. ZroZocycZusingested B. burgdorferi: 17.% of those examined on day 5 and 11% of those examined on day 15 were infected (Table 1). These spirochetes did not, however, survive trans-stadially; none of 84 resultant nymphal I. holocyclus, examined at day > 45, were infected. In contrast, 61% of nymphal I. dammini were infected when examined on day 5, and 72% on day 15; 75% of resultant nymphal I. dammini were infected. TABLE ~-VECTOR COMPETENCE OF Ixodes holocyclus AND Ixodes damminiFORTHEJDl STRAINOF Borrelia burgdorferi
Tick species
Trial 1 2 3
Total
I. I. I. I. I. I.
holocyclus dammini holocyclus dammini holocvclus dammini I. holocvclus I. dammini
Days post-larval repletion Day 5
Day 15
1/12t 216 2112 516 3112 416 6136 llj18
l/12 516 o/12 416 3112 416 4136 13;18
Day>45* O/28 518 O/28 618 0128 i/8 0184 18124
* Post-nymphal-molting. t No. ticks infected/No. ticks examined.
Several members of the genus Zxodes are competent vectors of B. burgdorferi, including I. dammini (see Donahue, Piesman & Spielman, 1987), I. scapularis (see Burgdorfer & Gage, 1986), I. ricinus (see Stanek, Burger, Hirschl, Wewalka & Radda, 1986), and I. dentatus (see Telford & Spielman, 1989). These observations led to the hypothesis that all members of the genus Zxodes may be competent vectors of B. burgdorferi. We have demonstrated that I. holocycZus does not maintain the JDl strain of B. burgdorferi trans-stadially and therefore could not serve as a competent vector of this strain of Lyme disease spirochete. The incompetence of I. holocyclus
as a vector of B. burgdorferi resembles that of Amblyomma and Dermacenror ticks in similar trials with JDI spirochetes (Piesman & Sinsky, 1988). The possibility that I. ZzofocycZusis involved in an enzootic cycle of B. burgdorferi in Australia has not been eliminated by our studies. Local strains of Borreliu may be adapted to transmission by local vectors. isolated
Indeed, spirochetes have from I. holocyclus removed
been from
recently dogs in
New South Wales (R. Barry and M. Wills, personal communication). Ideally, multiple colonies of I. holocyclus should be subjected to vector competence trials with Australian spirochete isolates. REFERENCES AI C., WEN Y., ZHANG Y., WANG S., QIU Q., SHI Z., Li D., CHEN D., LIU X. & ZHAO J. 1988. Clinical manifestations and epidemiological characteristics of Lyme disease in Hailin County, Heilongjiang Province, China. Annals of the New York Academy of Sciences 539: 302-3 13. ANDERSONJ. F. 1989. Epizootiology of Borrelia in Ixodes tick vectors and reservoir hosts. Reviews of Infectious Diseases 11: Sl451-1459. ANDERSON J. F., MAGNARELLIL. A., LEFEBVRER. B., ANDREADIST. G., MCANINCH J. B., PERNGG. & JOHNSON R. C. 1989. Antigenically variable Borrelia burgdorferi isolated from cottontail rabbits Ixodes dentatus in rural and urban areas. Journal of Clinical Microbiology 21: 13-
20. BURGDORFER W. & GAGE K. L. 1986. Susceptibility of the black-legged tick, Ixodes scapularis, to the Lyme disease spirochete, Borrelia burgdorferi. Zentralblatt fiir Bakteriologie, Mikrobiologie und Hvgiene: Series A 263: _15-20. BURGDORFERW., HAYES S. F. & CORWIN D. 1989. Pathophysiology of the Lyme disease spirochete, Borrelia burgdorferi, in ixodid ticks. Reviews of Infectious Diseases 11: S1442-1450. CENTEMFOR DISEASECONTROL1989. Lyme disease-united States, 1987 and 1988. Morbidity and Mortality Weekly Report 38: 668-672. CIESIELSKI C. C., MARKOWITZ L. E., HORSLEYR., HIGHTOWER A. W., RUSSELLH. & BROOMEC. V. 1989. Lyme disease surveillance in the United States, 1983-1986. Reviews of Infectious Diseases 11: S1435-1441. DONAHUEJ. G., PIESMANJ. & SPIELMANA. 1987. Reservoir competence of white-footed mice for Lyme disease spirochetes. American Journal of Tropical Medicine and Hygiene 36: 92-96. HABERBERGER R. L., JR, CONSTANTINE N. T., SCHWANT. G. & Woo~v J. N. 1989. Lyme disease agent in Egypt? Transactions of the Royal Society of Tropical Medicine and Hygiene 83: 556. KAWABATA M., BABA S., IGUCHI K., YUMAGUTI N. & RUSSELLH. 1987. Lyme disease in Japan and its possible incriminated tick vector, Ixodes persulcatus. Journal of Infectious Diseases 156: 854. KORENBERG E. I., KRYUCHECHNIKOV V. N., ANANYINAY. V. & CHERNUKHAY. G. 1986. Prerequisites of the existence of Lyme disease in the USSR. Zentraiblatt fir Bakteriologie, Mikrobiologie und Hygiene: Series A 263: 471472. LAWRENCER. H., BRADBURYR. & CULLENJ. S. 1986. Lyme disease on the New South Wales Central Coast. Medical Journal of Australia 145: 364.
Research
Note
111
MCCROSSIN I. 1986. Lyme disease on the New South Wales South Coast. Medical Journal of Australia 144:724-725. MUNROR. & DEKESOND. 1989. Lyme disease. Todays L@ Science 1: 32-39. PIESMAN J., MATHER T. N., SINSKY R. J. & SPIELMAN A. 1987. Duration of tick attachment and Borrelia burgdorferi transmission. Journal of Clinical Microbiology 25: 557-558. PIESMANJ., MATHER T. N., TELFORD S. R. III & SPIELMANA. 1987. Concurrent Borrelia burgdorferi and Babesia microti infection in nymphal Ixodes dammini. Journal of Clinical Microbiology 24: 446-447. PIESMAN J. 1988. Intensity and duration of Borrelia burgdorferi and Babesia microti infectivity in rodent hosts. Inlernational Journalfor Parasitology 18: 687-689. PIESMAN J. & SINSKYR. J. 1988. Ability of Ixodes scapularis, Dermacenror variabilis, and Amblyomma americanum (Atari: Ixodidae) to acquire, maintain, and transmit Lyme disease spirochetes (Borrelia burgdorferi). Journal of Medical Entomology 25: 336-339.
A. 1986. Borrelia transfer by ticks during their life cycle. Studies on laboratory animals. Zentralblatt fiir Bakieriologic, Mikrobiologie und Hygiene: Series A 263: 29-33. S~ANEKG., PLETSCHETTE M., FLAMM H., HIRSCHL A. M.. ABERER E., KRISTOFERITSCHW. & SCHMU~ZHARDE. 1988. European Lyme borreliosis. Annals of the New York Academy of Sciences 539: 274-282. STEWARTA., GLASS J., PATEL A., WATT G., CRIPPS A. & CLANCY R. 1982. Lyme arthritis in the Hunter Valley. Medical Journal of Australia I: 139. STONEB. F., GAUCI M. & THONG Y. H. 1987. Human toxic and allergic reactions to Australian ticks, particularly the paralysing tick Ixodes holocyclus. In: Progress in Venom and Toxin Research (Edited by GOPALAKHRISHNAKONE P. & TAN C. K.), pp. 556562. National University of Singapore Press, Singapore. STONE B. F. 1988. Tick paralysis, particularly involving Ixodes holocyclus and other Ixodes species. In: Advances in Disease Vector Research, Vol. 5 (Edited by HARRIS K. F.), pp. 61-85. Springer, New York.
STALLMAN N. 1987. Lyme borreliosis-a case report for Queensland. Communicable Disease Intelligence 21: 8-9.
TELFORDS. R. III & SPIELMAN A. 1989. Enzootic transmission of the agent of Lyme disease in rabbits. American
S~ANEKG., BURGERI., HIRSCHLA., WEWALKAG. & RADDA
Journal of Tropical Medicine and Hygiene 41: 482-490.
Parasitology
I
002&75l9/9l $3.00 + 0.00 Pergamon Press p/c Ausrralian Society for Parasitology
Vol. 21, No. I, pp. ICY&l I. 1991
RESEARCHNOTE VECTOR COMPETENCE OF THE AUSTRALIAN PARALYSIS TICK, IXODES HOLOCYCLUS, FOR THE LYME DISEASE SPIROCHETE BORRELIA BURGDORFERI JOSEPH PIESMAN* and BERNARD F. SToNEt * Division of Vector-borne Infectious Diseases, Center for Infectious Diseases, Centers for Disease Control, Public Health Service, U.S. Department of Health and Human Services, P. 0. Box 2087, Ft Collins, CO 80522, U.S.A. t Division of Tropical Animal Production, Long Pocket Laboratories, CSIRO, Private Bag No. 3, Indooroopilly, Queensland 4068, Australia (Received 19 July 1990; accepted 18 September 1990)
Abstract-PlasMAN J. and STONEB. F. 1991. Vector competence of the Australian paralysis tick, Ixodes Parasitology 21: 109-l 11. Clinical and serologic evidence of Lyme disease in Australia, including the typical rash, erythema migrans, has been reported. The vector tick transmitting Borreliu burgdorferi in Australia, however, has not been determined. The Australian paralysis tick, Zxodes holocycfus,is a logical candidate vector of the Lyme disease spirochete in Australia; therefore, we tested the ability of I. holocyclus to acquire and maintain a North American isolate of B. burgdorferi. Larval I. holocyclus ingested spirochetes, but none of 84 derived nymphs were infected. These experiments should be repeated with Australian strains of spirochetes. holocyclw, for the Lyme disease spirochete Borrelia burgdorferi. International Journalfor
INDEX KEY WORDS: Borrelia burgdorferi; paralysis tick; Ixodes holocyclus.
Lyme disease; vector competence;
LYME disease has recently become a public health concern of global importance. The majority of welldocumented human infections with the Lyme disease spirochete, Borrelia burgdorferi, have occurred in Europe and North America where thousands of cases have been reported (Stanek, Pletschette, Flamm, Hirschl, Aberer, Kristoferitsch & Schmutzhard, 1988; Ciesielski, Markowitz, Horsley, Hightower, Russell & Broome, 1989; Centers for Disease Control, 1989). Moreover, Lyme disease appears to be endemic in temperate areas of Asia, including parts of the Soviet Union (Korenberg, Kryuchechnikov, Ananyina & Chernukha, 1986), China (Ai, Wen, Zhang, Wang, Qiu, Shi, Li, Chen, Liu & Zhao, 1988), and Japan (Kawabata, Baba, Iguchi, Yumaguti & Russell, 1987). Isolated instances of human sera containing presumptive antibodies to B. burgdorferi have been reported from Africa (Haberberger, Constantine, Schwan &Woody, 1989). In Australia, seven cases of erythema migrans (EM), the typical rash associated with Lyme disease, were originally reported from the Hunter Valley, north of Sydney, New South Wales (Stewart, Glass, Patel, Watt, Cripps & Clancy, 1982). Additional cases of EM were discovered in New South Wales (McCrossin, 1986; Lawrence, Bradbury & Cullen, 1986), and in Queensland, serologic evidence of infection with B. burgdorferi was reported in 30 patients with arthritis (Stallman, 1987). Also, Munro
ticks; Australian
& Dickeson (1989) identified 11 seroreactive persons with a variety of symptoms who apparently acquired Lyme disease in Australia. The principal tick vectors of Lyme disease around the world are members of the Ixodes ricinus ‘complex’, which includes I. dammini, I. scapularis, I. paciJicus, I. ricinus and I. persulcatus (see Burgdorfer, Hayes & Corwin, 1989; Anderson, 1989). Another member of the genus, I. dentutus, the rabbit tick, has also been shown (Anderson, Magnarelli, Lefebvre, Andreadis, McAninch, Pemg & Johnson, 1989; Telford & Spielman, 1989) to be a competent vector of B. burgdorferi. No member of the I. ricinus ‘complex’ is extant in Australia; however, the Australian paralysis tick, I. holocyclus, is widespread. This tick species feeds predominantly on bandicoots (Stone, 1988), but frequently attacks people and domestic animals (Stone, Gauci & Thong, 1987). If Lyme disease exists in Australia, I. holocyclus would be a logical candidate vector. Accordingly, we tested the vector competence of I. holocyclus for B. burgdorferi Vector competence trials were conducted as previously described (Piesman & Sinsky, 1988; Piesman, 1988). Briefly, female hamsters (SO-150 g) were infected by allowing 10-12 nymphal I. dammini infected with the JDl strain of B. burgdorferi to feed on them. The JDl strain of B. burgdorferi was isolated from I. dammini in Ipswich, MA, U.S.A. and was maintained as previously described (Piesman,
109
110
J. PIE~SMAN and B. F. STONE
Mather, Sinsky & Spielman, 1987). At 1 month postexposure, larval I. holocyclus and I. dammini were fed to repletion on these infected hamsters. Midgut pre-
parations from larvae were subsequently examined for spirochetes by darkfield and direct fluorescent antibody microscopy (Piesman, Mather, Telford & Spielman, 1987). The colony of I. &mini used in these experiments was derived from females collected on Great Island, MA, U.S.A., and maintained with no evidence of transovarial generations.
spirochete transmission during The 1. holocyclus were obtained
three
from the CSIRO Long Pocket Laboratory colony, originally derived from ticks collected in southeastern Queensland and northern New South Wales. All ticks were maintained at 21°C and 97% RH. Ticks were examined for spirochetes on days 5, 15, and >45 post-larval feeding. The ticks examined after day 45 had molted to nymphs. The larval I. ZroZocycZusingested B. burgdorferi: 17.% of those examined on day 5 and 11% of those examined on day 15 were infected (Table 1). These spirochetes did not, however, survive trans-stadially; none of 84 resultant nymphal I. holocyclus, examined at day > 45, were infected. In contrast, 61% of nymphal I. dammini were infected when examined on day 5, and 72% on day 15; 75% of resultant nymphal I. dammini were infected. TABLE ~-VECTOR COMPETENCE OF Ixodes holocyclus AND Ixodes damminiFORTHEJDl STRAINOF Borrelia burgdorferi
Tick species
Trial 1 2 3
Total
I. I. I. I. I. I.
holocyclus dammini holocyclus dammini holocvclus dammini I. holocvclus I. dammini
Days post-larval repletion Day 5
Day 15
1/12t 216 2112 516 3112 416 6136 llj18
l/12 516 o/12 416 3112 416 4136 13;18
Day>45* O/28 518 O/28 618 0128 i/8 0184 18124
* Post-nymphal-molting. t No. ticks infected/No. ticks examined.
Several members of the genus Zxodes are competent vectors of B. burgdorferi, including I. dammini (see Donahue, Piesman & Spielman, 1987), I. scapularis (see Burgdorfer & Gage, 1986), I. ricinus (see Stanek, Burger, Hirschl, Wewalka & Radda, 1986), and I. dentatus (see Telford & Spielman, 1989). These observations led to the hypothesis that all members of the genus Zxodes may be competent vectors of B. burgdorferi. We have demonstrated that I. holocycZus does not maintain the JDl strain of B. burgdorferi trans-stadially and therefore could not serve as a competent vector of this strain of Lyme disease spirochete. The incompetence of I. holocyclus
as a vector of B. burgdorferi resembles that of Amblyomma and Dermacenror ticks in similar trials with JDI spirochetes (Piesman & Sinsky, 1988). The possibility that I. ZzofocycZusis involved in an enzootic cycle of B. burgdorferi in Australia has not been eliminated by our studies. Local strains of Borreliu may be adapted to transmission by local vectors. isolated
Indeed, spirochetes have from I. holocyclus removed
been from
recently dogs in
New South Wales (R. Barry and M. Wills, personal communication). Ideally, multiple colonies of I. holocyclus should be subjected to vector competence trials with Australian spirochete isolates. REFERENCES AI C., WEN Y., ZHANG Y., WANG S., QIU Q., SHI Z., Li D., CHEN D., LIU X. & ZHAO J. 1988. Clinical manifestations and epidemiological characteristics of Lyme disease in Hailin County, Heilongjiang Province, China. Annals of the New York Academy of Sciences 539: 302-3 13. ANDERSONJ. F. 1989. Epizootiology of Borrelia in Ixodes tick vectors and reservoir hosts. Reviews of Infectious Diseases 11: Sl451-1459. ANDERSON J. F., MAGNARELLIL. A., LEFEBVRER. B., ANDREADIST. G., MCANINCH J. B., PERNGG. & JOHNSON R. C. 1989. Antigenically variable Borrelia burgdorferi isolated from cottontail rabbits Ixodes dentatus in rural and urban areas. Journal of Clinical Microbiology 21: 13-
20. BURGDORFER W. & GAGE K. L. 1986. Susceptibility of the black-legged tick, Ixodes scapularis, to the Lyme disease spirochete, Borrelia burgdorferi. Zentralblatt fiir Bakteriologie, Mikrobiologie und Hvgiene: Series A 263: _15-20. BURGDORFERW., HAYES S. F. & CORWIN D. 1989. Pathophysiology of the Lyme disease spirochete, Borrelia burgdorferi, in ixodid ticks. Reviews of Infectious Diseases 11: S1442-1450. CENTEMFOR DISEASECONTROL1989. Lyme disease-united States, 1987 and 1988. Morbidity and Mortality Weekly Report 38: 668-672. CIESIELSKI C. C., MARKOWITZ L. E., HORSLEYR., HIGHTOWER A. W., RUSSELLH. & BROOMEC. V. 1989. Lyme disease surveillance in the United States, 1983-1986. Reviews of Infectious Diseases 11: S1435-1441. DONAHUEJ. G., PIESMANJ. & SPIELMANA. 1987. Reservoir competence of white-footed mice for Lyme disease spirochetes. American Journal of Tropical Medicine and Hygiene 36: 92-96. HABERBERGER R. L., JR, CONSTANTINE N. T., SCHWANT. G. & Woo~v J. N. 1989. Lyme disease agent in Egypt? Transactions of the Royal Society of Tropical Medicine and Hygiene 83: 556. KAWABATA M., BABA S., IGUCHI K., YUMAGUTI N. & RUSSELLH. 1987. Lyme disease in Japan and its possible incriminated tick vector, Ixodes persulcatus. Journal of Infectious Diseases 156: 854. KORENBERG E. I., KRYUCHECHNIKOV V. N., ANANYINAY. V. & CHERNUKHAY. G. 1986. Prerequisites of the existence of Lyme disease in the USSR. Zentraiblatt fir Bakteriologie, Mikrobiologie und Hygiene: Series A 263: 471472. LAWRENCER. H., BRADBURYR. & CULLENJ. S. 1986. Lyme disease on the New South Wales Central Coast. Medical Journal of Australia 145: 364.
Research
Note
111
MCCROSSIN I. 1986. Lyme disease on the New South Wales South Coast. Medical Journal of Australia 144:724-725. MUNROR. & DEKESOND. 1989. Lyme disease. Todays L@ Science 1: 32-39. PIESMAN J., MATHER T. N., SINSKY R. J. & SPIELMAN A. 1987. Duration of tick attachment and Borrelia burgdorferi transmission. Journal of Clinical Microbiology 25: 557-558. PIESMANJ., MATHER T. N., TELFORD S. R. III & SPIELMANA. 1987. Concurrent Borrelia burgdorferi and Babesia microti infection in nymphal Ixodes dammini. Journal of Clinical Microbiology 24: 446-447. PIESMAN J. 1988. Intensity and duration of Borrelia burgdorferi and Babesia microti infectivity in rodent hosts. Inlernational Journalfor Parasitology 18: 687-689. PIESMAN J. & SINSKYR. J. 1988. Ability of Ixodes scapularis, Dermacenror variabilis, and Amblyomma americanum (Atari: Ixodidae) to acquire, maintain, and transmit Lyme disease spirochetes (Borrelia burgdorferi). Journal of Medical Entomology 25: 336-339.
A. 1986. Borrelia transfer by ticks during their life cycle. Studies on laboratory animals. Zentralblatt fiir Bakieriologic, Mikrobiologie und Hygiene: Series A 263: 29-33. S~ANEKG., PLETSCHETTE M., FLAMM H., HIRSCHL A. M.. ABERER E., KRISTOFERITSCHW. & SCHMU~ZHARDE. 1988. European Lyme borreliosis. Annals of the New York Academy of Sciences 539: 274-282. STEWARTA., GLASS J., PATEL A., WATT G., CRIPPS A. & CLANCY R. 1982. Lyme arthritis in the Hunter Valley. Medical Journal of Australia I: 139. STONEB. F., GAUCI M. & THONG Y. H. 1987. Human toxic and allergic reactions to Australian ticks, particularly the paralysing tick Ixodes holocyclus. In: Progress in Venom and Toxin Research (Edited by GOPALAKHRISHNAKONE P. & TAN C. K.), pp. 556562. National University of Singapore Press, Singapore. STONE B. F. 1988. Tick paralysis, particularly involving Ixodes holocyclus and other Ixodes species. In: Advances in Disease Vector Research, Vol. 5 (Edited by HARRIS K. F.), pp. 61-85. Springer, New York.
STALLMAN N. 1987. Lyme borreliosis-a case report for Queensland. Communicable Disease Intelligence 21: 8-9.
TELFORDS. R. III & SPIELMAN A. 1989. Enzootic transmission of the agent of Lyme disease in rabbits. American
S~ANEKG., BURGERI., HIRSCHLA., WEWALKAG. & RADDA
Journal of Tropical Medicine and Hygiene 41: 482-490.
