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-TICKS: FOES OR FRIENDS?
+=====TICKS: FOES OR FRIENDS?=====
 By Stephen Doggett
 Anyone who has wandered through the Australian bush, particularly along the coastal fringe of eastern Australia, will have at some time in their life been bitten by ticks. The result is generally a mild itch at the bite site, but occasionally more severe consequences occur, which can be life threatening. Nevertheless, are the fears regarding ticks throughout the bushwalking community, warranted? Or are ticks one of the more maligned creatures in the Australian bush? However, to understand ticks, the diseases they transmit, and the risks they impose, a thorough knowledge of their biology and life cycle is required.
-What makes a tick, a tick? (Morphology). Ticks belong to the group of invertebrates known as the Arthropods, which also includes mites, spiders, insects and crustaceans. Australia has approximately 70 species and only a few are known to impact on human health. The most important tick by far, because of its ability to cause a variety of adverse effects, is the Paralysis tick, Ixodes holocyclus. The morphological features that distinguish ticks include, the possession of elongated mouthparts with rows of backward pointing teeth (which helps to anchor the tick in place once attached), and a structure called "Hailer's organ" which is present on both forelegs and has a sensory function for host detection. All ticks are external parasites on terrestrial vertebrates.
+**What makes a tick, a tick? (Morphology).**
+Ticks belong to the group of invertebrates known as the Arthropods, which also includes mites, spiders, insects and crustaceans. Australia has approximately 70 species and only a few are known to impact on human health. The most important tick by far, because of its ability to cause a variety of adverse effects, is the Paralysis tick, //Ixodes holocyclus//. The morphological features that distinguish ticks include, the possession of elongated mouthparts with rows of backward pointing teeth (which helps to anchor the tick in place once attached), and a structure called "Haller's organ" which is present on both forelegs and has a sensory function for host detection. All ticks are external parasites on terrestrial vertebrates.
 There are two groups of ticks, "Hard" ticks and "Soft" ticks, which differ in morphology and behaviour. Hard ticks are flattened (when not blood fed) and have a smooth body surface with a distinct thumbnail-like shield called a scutum. Eyes are sometimes present and the adult male and female stages are morphologically different. Soft ticks are not flattened, have no scutum and the body has a rough textured leathery covering. Eyes are not present on Australian Soft ticks and the adults are very similar. Soft ticks have little direct impact on human health in Australia and bushwalkers would rarely come into contact with them.
-The Life and Times of Ticks (The Life Cycle).
-Once on a host, the tick will then search for a site to feed and this may take up to two hours before attaching. On humans, the attachment site is often on the less exposed areas of the body such as among head hairs and the groin area (commonly on the scrotum in men). With kangaroos, a favoured locality for attachment is on the soft eyelids. After a site is chosen, knife edge structures called ichelicerad cut into the flesh and the tick's mouthparts are inserted. To avoid accidental or deliberate removal, the lower surface of the mouthparts has a series of backward,pointing barbs and some species even glue themselves into place. As the tick begins to feed, the host is injected with saliva that contains an anticoagulant to prevent the blood from clotting.
+**The Life and Times of Ticks (The Life Cycle).**
-The Sydney Bushwalker, January 1998
 Ticks have four distinct life stages; egg, larva, nymph and adult, which in total takes one to two years to complete, depending on the species. An adult female Hard tick may lay 2-3,000 eggs in one batch, while Soft ticks lay only a few at a time. After hatching, the larvae (0.5-1mm in size) must obtain a protein source, ie. blood, to be able to moult to the next stage of its life. Ticks may actively search for a host; they can detect the carbon dioxide emitted from an animal's breath, and also body heat. Other ticks passively search for a host. They will climb the nearest vegetation, wave their forelegs back and forth in a behaviour called 'questing' and latch onto almost any animal that wanders by, which often includes us. Contrary to popular belief, ticks do not jump as their legs are not evolved to do so. Nor do they "drop from trees", as ticks are susceptible to desiccation, they rarely climb far from the ground where the humidity levels are higher.
-For Hard ticks, the larvae will take blood from the host for several days and progressively swell up like a balloon, increasing maybe 100 fold in body weight. After engorgement, the larvae will randomly drop off and undergo metamorphosis to become a nymph, gaining an extra pair of legs (from 3 to 4 pairs). This transition will take several weeks. The nymph (1-2mm) will attempt to find a new host, blood engorge, and (if lucky) moult to the adult stage (2-3mm). The adult female, will feed for 6-8 days enlarging to around lcm in diameter, drop off the host, lay
-A Happy and Prosperous New Year to all.
+Once on a host, the tick will then search for a site to feed and this may take up to two hours before attaching. On humans, the attachment site is often on the less exposed areas of the body such as among head hairs and the groin area (commonly on the scrotum in men). With kangaroos, a favoured locality for attachment is on the soft eyelids. After a site is chosen, knife edge structures called 'chelicerae' cut into the flesh and the tick's mouthparts are inserted. To avoid accidental or deliberate removal, the lower surface of the mouthparts has a series of backward pointing barbs and some species even glue themselves into place. As the tick begins to feed, the host is injected with saliva that contains an anticoagulant to prevent the blood from clotting.
-The Sydney Bushwalker, January 1998- page 7
-children are, most susceptible. The main species responsible is the Paralysis Tick, while Ixodes hirsti from southwest Western Australia and Ixodes cornuatus from Tasmania have also been implicated but to a much lesser extent than Ixodes holoryclus. Signs of tick - envenomation include rOuced co-ordination, lymph node swelling facial paralysis (known as Bell's palsy) and general paralysis. Death from respiratory failure may follow if the patient is left untreated. Despite many pets dying annually, there has been no human fatality with the improvements in supportative medicine and with the introduction of an antivenene in the early 1940's. However, around every two years a child will be admitted to Westmead Hospital with signs of a mysterious paralysis that is subsequently traced to an -embedded Paralysis Tick. Currently, stocks of tick antivenene have declined to an alarmingly low level, and with no plans for any commercial production in the near future, the scenario for a preventable tragedy has been set.
+For Hard ticks, the larvae will take blood from the host for several days and progressively swell up like a balloon, increasing maybe 100 fold in body weight. After engorgement, the larvae will randomly drop off and undergo metamorphosis to become a nymph, gaining an extra pair of legs (from 3 to 4 pairs). This transition will take several weeks. The nymph (1-2mm) will attempt to find a new host, blood engorge, and (if lucky) moult to the adult stage (2-3mm). The adult female, will feed for 6-8 days enlarging to around lcm in diameter, drop off the host, lay eggs and die. Adult male Hard ticks rarely feed from an animal, although will occasionally suck the blood (haemolymph) of a female tick, while she is attached to a host.
-eggs.-and die. Adult male Hard ticks rarely feed froM arl animal, although will occasionally suck the blood (haemolymph) of a female tick, while she is attached to a host.
-Soft ticks do not continually stay attached to the host during each life stage. Instead they occur in areas' where animals rest, such as in bird nests and nikrirrial lairs, and take several small blood meals before each moult. These ticks also have several nymphal stages, from two to six.
+Soft ticks do not continually stay attached to the host during each life stage. Instead they occur in areas where animals rest, such as in bird nests and mammal lairs, and take several small blood meals before each moult. These ticks also have several nymphal stages, from two to six.
-For the bushwalker's menace, i e. the Paralysis tick, the life cycle has a distinct seasonality. The larval stage is most active from around January to around May, nymphs from May to September and adults from September to December. The adult female is the stage that can cause paralysis and is most likely to spread disease. Thus the greatest risk to the bushwalker, from this tick, is late in the year. The Paralysis tick is distributed along the coastal strip of eastern Australia and the Preferred habitat is moist galleys and rainforest areas.
-There are two unwanted side, effects that may occur as a tick feeds. Firstly, the anticoagulant that is pumped into the host, is often toxic, sometimes fatally so. Secondly, the tick may acquire _ a pathogen (a disease causing organism). When the tick feeds in later stages of its life, this pathogen can then be transmitted to other animals, including humans.
+For the bushwalker's menace, i e. the Paralysis tick, the life cycle has a distinct seasonality. The larval stage is most active from around January to around May, nymphs from May to September and adults from September to December. The adult female is the stage that can cause paralysis and is most likely to spread disease. Thus the greatest risk to the bushwalker, from this tick, is late in the year. The Paralysis tick is distributed along the coastal strip of eastern Australia and the preferred habitat is moist galleys and rainforest areas.
-Scratch my Back and I'll Scratch Yours! (Allergic Reactions).
-Allergic reactions in humans differ considerably between individuals. They can be in the form of a mild local 'skin reaction, to rashes accompanied by swelling with severe itching, to anaphylactic shock in hypersensitive individuals, which has the potential to be life threatening. For people who develop anaphylactic reactions, total avoidance of the bush may be the only life saving option. Occasionally, complications such as secondary infections may occur at the bite site after the tick has been removed.
+There are two unwanted side effects that may occur as a tick feeds. Firstly, the anticoagulant that is pumped into the host, is often toxic, sometimes fatally so. Secondly, the tick may acquire _ a pathogen (a disease causing organism). When the tick feeds in later stages of its life, this pathogen can then be transmitted to other animals, including humans.
-Feeling Numb? Could it be Paralysis?
-The saliva from certain species of tick contains a toxin that can cause a fatal paralysis and
+**Scratch my Back and I'll Scratch Yours! (Allergic Reactions).**
-Disease Spotting!
-In Australia, the Spotted Fevers are the main diseases transmitted by ticks to humans. There are two types, Queensland Tick Typhus and Flinders Island Spotted Fever, although they are uncommon with less than 50 cases per year in New South Wales. These afflictions are caused by rickettsia, a group of primitive bacterial-like. organisms. The signs of tick typhus include multiple rashes, headaches, fever, flu-like symptoms and lymph node tenderness. Tick typhus is treated with antibiotics, and rarely fatal. The disease is confined to the eastern coastal strip of Australia where it is transmitted to humans by the main vector, Ixodes holocyclus. Besides the rickettsias, several viruses have been isolated from ticks collected in the islands of' the Great Bather Reef. However, none of these have yet been associated with human disease.
+Allergic reactions in humans differ considerably between individuals. They can be in the form of a mild local skin reaction, to rashes accompanied by swelling with severe itching, to anaphylactic shock in hypersensitive individuals, which has the potential to be life threatening. For people who develop anaphylactic reactions, total avoidance of the bush may be the only life saving option. Occasionally, complications such as secondary infections may occur at the bite site after the tick has been removed.
-The other tick transmitted syndrome that has been the subject of much debate in Australia is that of Lyme disease. Lyme disease is named after the district of Lyme in the United States where the disease was first recognised. It has become the second most important emerging disease in the United States behind AIDS, with
-The Sydney Bush Walkers, founded 1927.
+**Feeling Numb? Could it be Paralysis?**
-Page 8 The Sydney Bushwalker, January 1998
-around 10,000 new cases - annually. The symptoms of Lyme disease are varied, and can be easily confused with other syndromes. If left untreated, the long-terms effects of Lyme disease can be extremely debilitating. Fortunately, the condition is readily cured with antibiotics. The debate in Australia concerns the presence of the disease in the country. Although human clinical cases have been reported since the early 1980s, there has been no conclusive evidence for the presence of the disease in Australia. A comprehensive survey of ticks using varying methodologies, undertaken by the Department of Medical Entomology at Westmead Hospital, found no evidence for any Borrelia (the spirochaete bacteria that causes Lyme disease) nor any other spirochaete. Other researchers believe there is some unidentified organism that causes a Lyme disease-like syndrome but the organism defies detection using current laboratory methods. However, in Australia, we do not have the tick vectors nor the animal reservoirs that are present in the endemic areas of the northern hemisphere, thus it is unlikely that true Lyme disease would exist herd. If there is some form of local bacteria that causes a Lyme-like disease, it is rare. Clearly the dellate will continue until (or if) a definitive causative organism is identified.
+The saliva from certain species of tick contains a toxin that can cause a fatal paralysis and children are, most susceptible. The main species responsible is the Paralysis Tick, while //Ixodes hirsti// from southwest Western Australia and //Ixodes cornuatus// from Tasmania have also been implicated but to a much lesser extent than //Ixodes holoryclus//. Signs of tick envenomation include reduced co-ordination, lymph node swelling, facial paralysis (known as Bell's palsy) and general paralysis. Death from respiratory failure may follow if the patient is left untreated. Despite many pets dying annually, there has been no human fatality with the improvements in supportative medicine and with the introduction of an antivenene in the early 1940's. However, around every two years a child will be admitted to Westmead Hospital with signs of a mysterious paralysis that is subsequently traced to an embedded Paralysis Tick. Currently, stocks of tick antivenene have declined to an alarmingly low level, and with no plans for any commercial production in the near future, the scenario for a preventable tragedy has been set.
-tick species into Australia (as seen by a recent record of Dermacentor variabilis from the United States), is real and a high degree of vigilance must be maintained.
-Beat the bite! (Prevention).
+**Disease Spotting!**
+In Australia, the Spotted Fevers are the main diseases transmitted by ticks to humans. There are two types, Queensland Tick Typhus and Flinders Island Spotted Fever, although they are uncommon with less than 50 cases per year in New South Wales. These afflictions are caused by rickettsia, a group of primitive bacterial-like. organisms. The signs of tick typhus include multiple rashes, headaches, fever, flu-like symptoms and lymph node tenderness. Tick typhus is treated with antibiotics, and rarely fatal. The disease is confined to the eastern coastal strip of Australia where it is transmitted to humans by the main vector, //Ixodes holocyclus//. Besides the rickettsias, several viruses have been isolated from ticks collected in the islands of the Great Bather Reef. However, none of these have yet been associated with human disease.
+The other tick transmitted syndrome that has been the subject of much debate in Australia is that of Lyme disease. Lyme disease is named after the district of Lyme in the United States where the disease was first recognised. It has become the second most important emerging disease in the United States behind AIDS, with around 10,000 new cases annually. The symptoms of Lyme disease are varied, and can be easily confused with other syndromes. If left untreated, the long-terms effects of Lyme disease can be extremely debilitating. Fortunately, the condition is readily cured with antibiotics. The debate in Australia concerns the presence of the disease in the country. Although human clinical cases have been reported since the early 1980s, there has been no conclusive evidence for the presence of the disease in Australia. A comprehensive survey of ticks using varying methodologies, undertaken by the Department of Medical Entomology at Westmead Hospital, found no evidence for any //Borrelia// (the spirochaete bacteria that causes Lyme disease) nor any other spirochaete. Other researchers believe there is some unidentified organism that causes a Lyme disease-like syndrome but the organism defies detection using current laboratory methods. However, in Australia, we do not have the tick vectors nor the animal reservoirs that are present in the endemic areas of the northern hemisphere, thus it is unlikely that true Lyme disease would exist here. If there is some form of local bacteria that causes a Lyme-like disease, it is rare. Clearly the debate will continue until (or if) a definitive causative organism is identified.
+**Feel like something Exotic? - Diseases beyond the ocean.**
+Overseas, there is a huge range of tick borne diseases including those caused by various viral, bacterial, rickettsial and protozoan pathogens. Some of these diseases, such as Colorado Tick Fever in the United States, produce mild flu like symptoms which often go undiagnosed. Others like Rocky Mountain Spotted Fever in the United States and Tick Borne Encephalitis throughout Europe, have high fatality rates (up to 30%) in untreated patients. Additionally, in the last twenty years several new and emerging human tick borne diseases have been identified. These include Lyme disease (as discussed above), Ehrlichiosis (caused by the rickettsia, //Ehrlichia//, and infection may result in death from internal haemorrhaging) and Babesiosis (caused by a malaria-like protozoan parasite, //Babesia microti// with various symptoms). The potential threat for the introduction and establishment of these diseases, and also foreign tick species into Australia (as seen by a recent record of //Dermacentor variabilis// from the United States), is real and a high degree of vigilance must be maintained.
+**Beat the bite! (Prevention).**
 A variety of methods exist to reduce the possibility of tick bite and prevention is best achieved via some form of personal protection. People who bushwalk in tick infested areas need to use insect repellents, particularly those containing the chemical DEET, and these should be applied regularly to clothing. Once a tick is embedded into the skin, the preferable method for removal is to place a small amount of an insect repellent onto the tick, which kills the tick, and it can later be removed with the aid of a fine tipped pair of forceps. Other methods such as using nail polish remover, kerosene, vaseline or turps can cause the disgorgement of the gut contents into the host. For an animal in late stage paralysis, this may be fatal. If there are any ill effects after removing a tick, then a medical practitioner should be consulted.
-Ticks our Friends?
-In reality, ticks generally are more of a nuisance and tend to be only an occasional threat to our health, particularly if compared with other dangers which confront the bushwalker. Diseases from mosquitoes (especially Ross River disease) are far more common (by several hundred fold) and accidents while walking represents a much greater risk than any tick- borne disease. Of course, the Australian bush is the residence of the tick and it is we who intrude into their home, rather than vice-a-versa. We often forget that the Paralysis tick is a native animal and has every right to live and survive in its own natural habitat, as does something which we consider furry and cute.
+**Ticks our Friends?**
-Feel like something Exotic? - Diseases beyond the ocean.
-Overseas, there is a huge range of tick borne diseases including those caused by various viral, bacterial, rickettsial and protozoan pathogens. Some of these diseases, such as Colorado Tick Fever in the United States, produce mild flu like symptoms which often go undiagnosed. Others like Rocky Mountain Spotted Fever in the United States and Tick Borne Encephalitis throughout Europe, have high fatality rates (up to 30%) in untreated patients. Additionally, in the last twenty years several new and emerging human tick borne diseases have been identified. These include Lyme disease (as discussed above), Ehrlichiosis (caused by the rickettsia, Ehrlichia, and infection may result in death from internal haemorrhaging) and Babesiosis (caused by a malaria-like protozoan parasite, Babesia microti with various symptoms). The potential threat for the introduction and
+In reality, ticks generally are more of a nuisance and tend to be only an occasional threat to our health, particularly if compared with other dangers which confront the bushwalker. Diseases from mosquitoes (especially Ross River disease) are far more common (by several hundred fold) and accidents while walking represents a much greater risk than any tick-borne disease. Of course, the Australian bush is the residence of the tick and it is we who intrude into their home, rather than vice-a-versa. We often forget that the Paralysis tick is a native animal and has every right to live and survive in its own natural habitat, as does something which we consider furry and cute.
-establishment of these diseases, and also foreign
-A Happy and Prosperous New Year to all.
+As ticks require animals as source for blood, the presence of ticks in an area suggests a healthy environment, usually with a variety of native marsupials. But, with urban development, bush fragmentation, feral animals, pollution and the many other forms of human activity which degrade native bushland, maybe it is the tick that is under the greater threat and not us humans.
-At Eastvvood Camping Centre
-WE'LL GET YOU COVERED
+**FURTHER READING**
-eastwood
-ccarrptpvg
+PEARN J. (1977). **The Clinical Features of Tick Bite.** //Medical Journal of Australia.// 2: 313-6.
-(02) 9858 3833
-Packs, Tents, Sleeping- bags, Abseiling gear & Ropes, Boots Clothing and everthing else you'll need to replace your prehistoric gear.
+RUSSELL R.C., S.L. DOGGETT, R. MUNRO, J. ELLIS, D. AVERY, C. HUNT, and D. DICKESON. (1994). **Lyme disease: A search for the causative agent in ticks in southeastern Australia.** //Epidemiology and Infection.// 112: 375-384.
-Give us a call now
-Trelawney Street (PO Box 131) Eastwood. N.S.W. 2122
+**WEB SITES**
-Page 10 The Sydney Bushwalker, January 1998
-As ticks require animals as source for blood, the
+<http://www.peg.apc.org/~ullavet/tick.html#Life> (information on //Ixodes holocyclus//, largely from a veterinary aspect).
-presence of ticks in an area suggests a healthy
-environment, usually with a variety of native
+<http://www.uri.edu/attsci/zool/ticklab/HomePg.html> (information from America for ticks, Lyme disease, ElulichiosiS, Human Babesiosis).
-marsupials. But, with urban development, bush
-fragmentation, feral animals, pollution and the
+<http://www.dis.strath.ac.uk/vie/LymeEU/index.htm> (Lyme disease from Europe; tick biology, control and images).
-many other forms of human activity which
-degrade native bushland, maybe it is the tick
+**//About the author//**: Stephen Doggett is with the Department of Medical Entomology, University of Sydney & ICPMR, Westmead Hospital, Westmead NSW 2145. In November 1997 Stephen gave a talk about Ticks and other little things that bite to the SBW at the Kirribilli clubrooms. Stephen also can be reached via the Internet on E-mail <stephend@cidm.sahs.nsw.gov.au>.
-the greater threat and not us
-that is under humans.
-FURTHER READING
-PEARN J. (1977). The Clinical Features of Tick Bite. Medical Journal of Australia. 2: 313-6.
-RUSSELL R.C., S.L. DOGGETT, R. MUNRO, J. ELLIS, D. AVERY, C. HUNT, and D. DICKESON. (1994). Lyme disease: A search for the causative agent in ticks in southeastern Australia. Epidemiology and Infection.
-: 375-384.
-WEB SITES <http://www peg apc org/--ullavet/tick html#Life> (information on Ixodes holocyclus, largely from a veterinary aspect).
-<http://www uri eduJattsci/zoollticklab/HomePg html> (information from America for ticks, Lyme disease, ElulichiosiS, Human Babesiosis).  <http://www dis strath ac ukivie/LyrneEU/index htm> (Lyme disease from Europe; tick biology, control and images).
-About the author: Stephen Doggett is with the Department of Medical Entomology, University of Sydney & ICPMR, Westmead Hospital, Westmead NSW 2145. In November 1997 Stephen gave a talk about Ticks and other little things that bite to the SBW at the Kirribilli clubrooms. Stephen also can be reached via the Internet on E-mail <stephend@cidm wsahs nsw gov au>.
 SOCIAL NIGHT: 28 JAN. 1998
 At the clubroom: Alan Norman, senior NP&WS ranger based at Ulladulla south of Nowra will talk on wilderness and national parks management from the ranger's perspective. Come and hear how the NP&WS manage land, flora and fauna (including homo sapiens).