Review of exotic Over a 25-year period to January 2005, there have been 91 interceptions of exotic entering New Zealand. interceptions in New Zealand The number of interceptions is increasing, and in 2004 since 1980 exotic ticks were detected on 12 occasions. Ticks are blood-feeding external parasites of mammals, birds and reptiles. Approximately 850 species have been described 45 14 worldwide(1)(2). There are two well established families: the 40 (hard ticks) and Argasidae (soft ticks). Both are important vectors 12 of disease-causing agents to humans and throughout the 35 10 tions world. Ticks transmit the widest variety of pathogens of any blood- s p g 30 sucking : bacteria, rickettsiae, protozoa and viruses. 8

and do 25

6 Tick interce The life cycle of ticks may be classified according to their location 20 Imported goods, passengers Imported goods, when they moult between life stages – either on the host (one-host 4 15 tick) or off the host (multi-host tick). All ticks intercepted in New 10 2 Zealand are three-host ticks, requiring a different host for every life 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 stage: larva, nymph and adult. Imported goods (NZ$, billions) Arriving passengers (*100,000) Imported dogs (*100) Tick interceptions

There are three endemic tick species in New Zealand and six others Figure 1: Number of tick interceptions per year and the relationship between interceptions and imported goods, dogs and passengers that are shared with other countries; most are found on wild birds(3). The cattle tick Haemaphysalis longicornis is the only one Investigation (NCDI) accounting for 22 incursions(12)(13). of economic importance to livestock and agriculture(4). It feeds on Three exotic ticks discovered on animals entering New Zealand most domestic animals and is widespread in the North Island and through quarantine facilities (pre-border) were not investigated in areas of the northern part of the South Island. by NCDI, and neither were three reports from medical laboratories (Heath ACG, personal communication). Over the last 25 years An increasing number of tick interceptions are being investigated. annual exotic tick interceptions have steadily increased (see Exotic tick interceptions have been reviewed in 1995(5) and in Figure 1). 2000(6). This article reviews and records further interceptions and looks at entry pathways, country of origin and biosecurity measures Twelve different exotic tick species have been identified so far. The in response to confirmed incursions. most common species to arrive here are holocyclus (24%) and (46%). The relative numbers of the seven Tick interceptions most commonly identified ticks are shown in Figure 2. All exotic Between 1955 and 1980 only seven tick interceptions were ticks intercepted so far have been ‘hard’ ticks. Interceptions of three reported(7)(8)(9)(10)(11). Between 1980 and December 2000 a further 63 species of (D albipictus, D variabilis, D silvarum) in were reported(6). From January 2000 until January 2005, there were 2004 on humans are of concern because the genus contains some 33 tick investigations conducted at the National Centre for Disease species that are troublesome for livestock(14). Dermacentor species Most ticks (57 of a total of 91, or 63%) arrived from . 5 There were 18 instances of ticks arriving from Asia and the Pacific Others Ambylomma 7 triguttatum Islands including Hawaii. To date, no ticks have come from South 3 America. Figure 3 shows the number of interceptions per Haemaphysalis longicornis country or region of origin. 4 Most ticks arrived in this country attached to dogs (34 of a total of 91, or 37%) or to humans or their clothing 4 Rhipicephalus sanguineus (34, or 37%). Fifteen arrived in luggage, containers or 42 Ixodes other routes not involving mammals (Figure 4). pacificus 4 Discussion Ixodes holocyclus Suggested causes for the increasing number of tick 22 investigations, interceptions and incursions include:

• heightened awareness by the general public of biosecurity issues, resulting in more reporting; Figure 2: Tick interceptions by species

page 7 Surveillance 32(3) 2005 Africa Unknown 2 Unknown 3 2 Other Europe animals 4 5

USA and Canada 8 Objects 15 Dogs 34

Asia and Hawaii 18 Australia 57

Humans 34

Figure 3: Country or region of origin Figure 4: Host or object on which tick enters

• an increase in dog imports (Figure 1). Dogs, together with disease (endemic in the USA and parts of Europe)(24)(25). It has a humans, are the most important hosts carrying ticks into New worldwide distribution between the latitudes of 50° North and Zealand (Figure 4); 35° South, suggesting it could establish in the northern parts of • an increase in passenger arrivals, an important host or carrier of the North Island. The brown dog tick can also establish in heated ticks (Figure 4). In 2004 almost 4.2 million people arrived here, houses if suitable hosts are present(26)(27). On three occasions, in compared with 2.2 million in 1994. Forty percent came from 1979(7), 2000(28) and 2004(13), a New Zealand house became infested. Australia and the Pacific Islands(15); Each time the tick was eradicated by applying chemotherapeutic treatments to houses, household effects, surrounds and animals. • the value of imported goods increased by 77% in the last ten years (Figure 1), indicating an increased volume of goods Ixodes holocyclus, the Australian paralysis tick, is the second most imported in bulk or containers, the third most important frequently intercepted tick (Figure 2). It is usually found attached carrier of ticks into this country; 33% of goods arrived here to human travellers(6). Adult female ticks can induce paralysis in from Australia and 17% from the USA and Japan(15); humans and animals and are potentially deadly(7). Ixodes holocyclus • use of acaricides with less than full efficacy against ticks. is a coastal species in eastern Australia, which has, in parts, a climate similar to the north of the North Island of New Zealand, suggesting Haemaphysalis longicornis, the cattle tick, has been in New Zealand that I holocyclus has a limited ability to establish here. since about 1900(5). It can affect livestock productivity(4) and deer can be particularly affected by heavy infestations(16). Since 1980 All exotic ticks are notifiable under the Biosecurity Act 1993. there have been four re-introductions recorded, all potentially Most R sanguineus ticks are reported by veterinary practitioners. capable of introducing exotic tick-borne disease. The only known Members of the public also notify the Ministry of Agriculture tick-borne disease transmitted by H longicornis in New Zealand is and Forestry (MAF) after finding ticks attached to a person or in the mildly pathogenic Theileria orientalis/buffeli. The absence of luggage from overseas destinations. Q-fever (Coxiella burnetii) in New Zealand may be because of the The effectiveness of existing biosecurity measures is constantly limited vector potential of H longicornis(17)(18). monitored and reviewed. MAF recently introduced measures in Rhipicephalus sanguineus, the brown dog tick, is the most response to the increasing incidence of interceptions. All cats and commonly intercepted exotic tick and most have come from dogs arriving in New Zealand from countries that do not require Australia. It is a vector for a wide range of infectious agents, quarantine (Australia, United Kingdom, Sweden, Norway, Hawaii particularly those affecting dogs, such as Babesia canis, B gibsoni and Singapore) are examined closely for ticks on arrival(29). All and Ehrlichia canis(19)(20)(21). The tick-borne diseases B canis and cats and dogs in quarantine receive acaricide treatment within the B gibsoni are endemic in Australia(22). There is no evidence of first three days of arrival and are examined by a veterinarian prior E canis in Australia(23). Rhipicephalus sanguineus also has the to release. Only one interception in 2004 was the result of a tick potential to transmit the zoonotic or Lyme attached to an imported post-clearance(13).

page 8 Surveillance 32(3) 2005 References (18) Heath A. Vector competence of Haemaphysalis longicornis with particular reference to blood parasites. Surveillance 29(4),12-4, 2002. (1) Furman D, Loomis E. The ticks of California. University of California (19) Skotarczak B, Adamska M, Supron M. Blood DNA analysis for Ehrlichia Publications, Bulletin of the California Insect Survey, University of California (Anaplasma) phagocytophila and Babesia spp. of dogs from Northern Poland. Press, California, 1984. Acta Veterinaria Brno 73, 347-51, 2004. (2) Varma M. Ticks and mites (). In: Lane R, Crosskey R (eds). Medical (20) Venzal JM, Castro O, Cabrera PA, Souza CG, de Guglielmone AA. Ticks of Insects and . Pp 597-658. Chapman & Hall, London, 1993. medical and veterinary importance in Uruguay. Entomologia y Vectores 10, (3) McKenna PB. The tick fauna of New Zealand. Surveillance 23(4), 27, 1996. 635-50, 2003. (4) Heath ACG. Ectoparasites of livestock in New Zealand. New Zealand Journal (21) Helan JA, Haddadzadeh H, Shirani D, Khazrainia P, Mostofi S. Histopathologic, of Zoology 21, 23-38, 1994. hematologic and clinical study on canine . Journal of the Faculty of (5) Fairley R, Heath A. Exotic ticks intercepted in New Zealand since 1980. Veterinary Medicine, University of Tehran, 56(3), e93-e96, 2001. Surveillance 24(1), 21-2, 1997. (22) Jefferies R, Ryan, UM, Muhlnickel CJ, Irwin PJ. Two species of canine (6) Heath ACG. Exotic tick interceptions 1980-2000. Surveillance 28(4), Babesia in Australia: detection and characterization by PCR. Journal of 13-5, 2001. Parasitology 89, 409-12, 2003. (7) Heath ACG, McColl HP, Tenquist JD. Accidental importation of the brown (23) Mason RJ, Lee JM, Curran JM, Moss A, van der Heide B, Daniels PW. dog tick, Rhipicephalus sanguineus. New Zealand Veterinary Journal 28, Serological survey for Ehrlichia canis in urban dogs from the major population 168-9, 1980. centres of northern Australia. Australian Veterinary Journal 79, 559-62, 2001. (8) Hutton JB. Tick (Ixodes holocyclus) paralysis in an imported dog. New Zealand (24) Burgdorfer W, Barbour AG, Hayes SF, Benach JL, Grunwaldt E, Davis JP. Lyme Veterinary Journal 22, 173, 1974. disease – a tick-borne spirochetosis? Science USA 216, 1317-19, 1982. (9) McKenna PB, Tenquist JD, Ker J. The brown dog tick (Rhipicephalus (25) Parola P. Tick-borne rickettsial diseases: emerging risks in Europe. sanguineus) on an imported dog. New Zealand Veterinary Journal 23, Comparative Immunology, Microbiology and Infectious Diseases 27, 242, 1975. 297-304, 2004. (10) Richardson C. Interception of Insects, Mites and other Animals Entering (26) Fox TSM. Establishment of the tropical tick, Rhipicephalus sanguineus, in a New Zealand 1966-1972. Plant Health Diagnostic Station, Levin, 1979. house in London. Veterinary Record 116, 661-2, 1985. (11) Ward DMA. Interception of Insects, Mites and other Animals Entering New (27) Sibomana G, Geerts S, Vries Td. The establishment of Rhipicephalus Zealand 1955-1965. Government Printer, Wellington, 1968. sanguineus (Latreille, 1806) inside houses in Belgium. Annales de la Societe (12) Poland R. Animal disease surveillance. Surveillance 32(2), 9-12, 2005. Belge de Medecine Tropicale 66, 79-81, 1986. (13) Stone M. Quarterly report of investigations of suspected exotic disease. (28) Anon. Suspected exotic disease investigations. Surveillance 27(3), Surveillance 32(1), 16-20, 2005. 22-3, 2000. (14) Heath ACG. Failure of famphur treatment of Wapiti (Cervus canadiensis) (29) Anon. Inspection of Imported Cats and Dogs for Ticks. to affect egg laying and embryogenesis in the Winter tick, Dermacentor http://www.biosecurity.govt.nz/imports/animals/tick-inspection.htm, 2005. albipictus. New Zealand Veterinary Journal 34,176, 1986. Leo Loth (15) Anon. Imports and exports NZ 1994-2004. New Zealand Statistics website: http://www.stats.govt.nz/economy/exports-and-imports/default.htm, 2005. National Centre for Disease Investigation (16) Wilson PR, Heath ACG, Bond DB, Roberts HM. Ticks on deer. New Zealand PO Box 40742 Veterinary Association; Deer Branch Course No 4: Proceedings of a Deer Upper Hutt Course for Veterinarians, Dunedin, July 1987, No 4, 9-27, 1988. (17) Worthington RW. New Zealand is free from Q fever. Surveillance 28(4), Email: [email protected] 3-4, 2001.

page 9 Surveillance 32(3) 2005