Did you know that your pet can get Lyme Disease? What symptoms would you look out for? How can it be prevented?
Lyme Disease is primarily spread in Europe by the sheep or castor bean tick (official name ixodes ricinus). Your dog is at risk as ticks prefer to hide in areas such as tall grasses, the shady cover of trees, under fallen leaves & in heath land where dogs may like to run & explore.
Ticks will be ready & waiting in the grass by assuming a questing position where they hold their front legs out ready to attach on with hooks on the end of their legs. As soon as they sense carbon dioxide from a passing host they will be ready & waiting. Dog fur can easily hide a tick as they are incredibly small. A nymph tick is only about 1.5 mm in size & an adult can be 2-3 mm or the size of a sesame seed. Generally a tick will crawl around in the fur trying to find a safe & comfy spot to feed such as under the ear or chin, or tucked away on the soft belly of the dog. An owner may dismiss the black speck as a bit of dirt & not realise it was a tick until it begins to expand days later. Unfortunately, an expanded (engorged) tick will be full of the dog’s blood & will be getting ready to drop off, so it can moult & prepare itself for the next stage in its life.
What is the life cycle?
The adult female lays many eggs, often reaching the thousands. The eggs hatch into 6 legged larvae which are tiny, the size of a small stop at the end of this sentence. At this stage they will look out for small hosts such as mice. They need a blood meal before they can develop into a nymph, however ticks may last for months between snacks! It is crucial that they do not dehydrate, so ticks favour damp or well shaded areas. After the 1st feed they will drop off & crawl off in a safe area to moult & take the shape of an 8 legged nymph tick. Nymph ticks will be questing higher in the tall grasses which enables them to target larger hosts. Any host passing by such as mice, ground feeding birds, hedgehogs, squirrels, even dogs & humans can be prey to the waiting tick.
After a nymph tick has fed for several days they will plump up several times their own size & drop off again, ready to moult into their next life stage. An adult tick will be on the search for even larger hosts such as deer, sheep & cattle. An engorged female tick can expand to many times her size. At this stage after she has been feeding, a male will mate her where she will crawl off to lay her eggs & die. Some animals will carry a variety of different sized ticks & not all ticks will be infected with Lyme. However, the longer a tick has been allowed to feed, the higher the chance that infection could take place, so it essential to look out for any hitch hikers on your pets, children & even yourself after time spent outdoors.
Tick Talk Ireland has just released a vets study. More details below:
We are presently undertaking a project looking at the number of ticks found on companion & farm animals here in Ireland. This was influenced by a similar study in the UK, whereby 15% of dogs brought into vets were harbouring ticks. http://bristol.ac.uk/news/2011/7541.html This has the potential to cause health problems for the dog as well as the owner.
We are therefore looking for vets willing to help us gain an idea of the spread of ticks on companion & farm animals throughout Ireland.
* Do you frequently see ticks being brought in on animals?
* Is there are a concern that tick-borne infections may be rising?
* Are owners aware of the dangers of ticks on their pets / farm animals, not only to the animal but also to their own health?
Included in the survey are 10 questions.
Some (with *) require an answer before continuing – others will only need completing where applicable.
The time for completion should only take a couple of minutes.
If you would like to help us please click here to continue with the survey.
You are welcome to forward onto any vets in your area who may be interested!
If you spot any ticks when out walking or being brought into the house on humans or pets, please notify us in our survey ‘Tick Talking while you’re Walking‘!
For all our other surveys check out: http://ticktalkireland.org/surveys.html
Below are some useful studies & resources about tick-borne infections in pets.
Pets And Owners At Risk From Lyme Disease in The New Forest
Posted by: Richard L on: 10 August 2009
As the PDSA warns us that the 150% increase in suspected cases of Lyme Disease could be the tip of the iceberg, we remind you how to avoid Lyme Disease and what symptoms to look out for.
Lyme disease is transmitted by a tick bite that carries the bacterium Borrelia burgdorfei. It transmits the bacterium to you as it feeds on your blood. It can spread to humans, dogs and cats, plus some other species. Symptoms include a rash, fever, lameness and fatigue as well swollen lymph glands and nerve damage.
Ticks are very small (about the size of a poppy seed) and can easily be overlooked. Most ticks are not infected with the bacteria that cause Lyme disease. Even if a tick is infected, it does not spread the bacteria in the first few hours of its feed, so there is a very low risk of infection to both pets and humans if a tick is removed quickly.
A tick bite usually looks like a lump with a small scab on the skin surface at the site of the bite. Most people with Lyme disease then develop a reddish skin rash in a ring shape, and this may be the only sign of infection. The rash spreads out from the site of a bite after three to 30 days. Other common symptoms of early Lyme disease include tiredness, headache, joint pains and flu-like symptoms.
Early detection and treatment of the disease helps to relieve the symptoms and shorten the illness. For this reason, it is important to be aware of the symptoms, particularly the rash, so that treatment can be given early.
Pet owners are advised to prevent themselves being bitten by covering up when in woods or long grass – and to check their pets after walks for signs of ticks.
Some areas are more prone to infected ticks. In the UK, Lyme disease occurs mainly in the New Forest, Salisbury Plain, Exmoor, the South Downs, parts of Wiltshire and Berkshire and Thetford Forest. It’s also found in the Lake District, the Yorkshire Moors and the Scottish Highlands and Islands. Elsewhere, areas of high incidence are the United States, France, Germany, Austria, Sweden, Czech Republic, Slovakia, Slovenia, Croatia, Romania, Bulgaria and the Baltic republics. Peak times of the year for tick bites are late spring, early summer and autumn.
Unfortunately, some of the symptoms of Lyme Disease are similar to those of Swine Flu, but the characteristic rash should help to confirm a diagnosis. Symptoms can vary from patient to patient and sometimes there are no symptoms at all.
In around 70-80% of cases, the first sign of infection is usually a rash known as erythema migrans. The rash appears between one and four weeks after the bite. It spreads gradually from the site of the tick bite and can cover much of the trunk of the body. Other symptoms include:
* headache, and
* aching muscles and joint,
* stiff neck, and
* swollen glands.
If you suspect that you have been bitten by a tick and you have the symptoms described above, see your GP or call NHS Direct.
What About Your Pet?
Senior Veterinary Surgeon Elaine Pendlebury said, “The number of suspected cases of Lyme disease in dogs and cats is just the tip of the iceberg, in my opinion. Pet owners may not consult their vet as they are often unaware of the dangers of tick bites and that an infected pet may need early antibiotic treatment.
“It is essential that owners are aware of the dangers of ticks, particularly during the summer months, because both you and your pet could be affected. Tick bites can be difficult to detect as they are relatively painless but symptoms of the infection can develop months, even years, after the tick bite.
“One way for owners to reduce the risk of Lyme disease in pets is to use tick control products as recommended or prescribed by their vet. They should also check their dogs for ticks regularly after a walk, and immediately consult their vet if their dog shows any of the signs of Lyme disease.
“When a pet has been in woods or long grass, owners should check the fur, using rubber gloves, as an infected tick can bite both the pet and the human. If an owner does find ticks on their pet then their vet can safely remove it and also give advice on how an owner could effectively do this in the future.”
PDSA vets also advise dog owners to cover up when walking their pets, particularly in the countryside or park. Owners should wear long-sleeved tops and full-length trousers and after a walk a person should check their armpits, groin, belly button, neck and head for ticks. The number of people being diagnosed with Lyme disease in the UK has also steadily risen over the past 10 years.
Ticks are on the march in Britain
Press release issued 23 March 2011
The prevalence of ticks attaching to dogs in Great Britain has been mapped by scientists as part of a national tick survey. The findings reveal that the number of dogs infested with the blood-sucking parasites was much higher than expected. The study also confirms that a European tick species now exists in Great Britain.
The research, carried out by academics from the University of Bristol’s Veterinary Parasitology Group and published in the journal Medical and Veterinary Entomology, found that at any one time 14.9 per cent of dogs were infested with ticks.
More than 3,500 dogs were examined for ticks at 173 vet practices across Great Britain between March and October 2009. The researchers found that gundog, terrier and pastoral breed groups were more susceptible to getting ticks than others, and that longer-haired dogs were more susceptible to ticks than short-haired dogs.
Samples of a tick species only found previously in continental Europe were also found in locations in west Wales and south east England, adding to growing evidence that this tick, deemed as ‘exotic’, is now a permanent resident in Great Britain.
Professor Richard Wall, head of the Veterinary Parasitology Group at the University, said: “This is an important study because the results suggest that the risk of tick infestation is far higher in dogs than was previously thought. This has serious implications for the incidence of tick-borne disease. The study also confirms that a non-native species of tick, which is also a major disease vector in Europe, is now established in southern England. It will be of considerable interest to monitor its spread.”
Dogs can be infected with a number of tick-borne diseases, including Lyme disease. A non-native species of tick could help spread new diseases from Europe in the UK.
Current concerns over the potential impacts of changing climate and increased global movement of people and companion animals on the distribution of ectoparasites highlight the need for an accurate understanding of existing prevalence patterns, without which future changes cannot be detected.
Faith Smith, lead author on the study from the University’s School of Biological Sciences, added: “The study represents a major large-scale analysis of ticks in Britain – and the data could aid work to help predict the effects of climate change on tick distributions and disease spread.”
The study entitled ‘Prevalence, distribution and risk associated with ticks infesting dogs in Great Britain’, was funded by the Natural Environment Research Council [NERC] and Merial Animal Health Ltd.
Please contact Faith.Smith@bristol.ac.uk for further information.
Pics on site:
A map illustrating the prevalence of ticks attaching to dogs in Great Britain
This is an important study because the results suggest that the risk of tick infestation is far higher in dogs than was previously thought. This has serious implications for the incidence of tick-borne disease. The study also confirms that a non-native species of tick, which is also a major disease vector in Europe, is now established in southern England. It will be of considerable interest to monitor its spread.
Professor Richard Wall, head of the Veterinary Parasitology Group
Lyme Disease and Pets
(NB – since writing this article the link above is now broken, but have kept here for informational purposes)
Lyme disease can affect individual pets differently. Some animals may display no symptoms. Other animals may develop fever, loss of appetite, painful joints, lethargy, and vomiting. If left untreated, the spirochete may damage the eyes, heart, kidneys, and nervous system. Lyme disease has been diagnosed in humans, dogs, cats, horses, goats, and cattle. Other species may also be at risk.
Cats may show lameness, fever, loss of appetite, fatigue, eye damage, unusual breathing, or heart involvement. Many cats do not show noticeable symptoms, despite being infected.
Infected dogs may be lethargic, have a poor/loss of appetite, or a fever (103° – 105 ° F). Dogs may also experience lameness shifting from one joint to another, fatigue, kidney damage or failure, heart disorders, or neurologic involvement (e.g. aggression, confusion, overeating, seizures). Dogs can be infected with the Lyme bacterium but not exhibit any noticeable symptoms. Dogs appear to have the same expression of disease as humans, therefore, humans have been considered an animal model for dogs. Transplacental transmission has occurred in dogs.
Many cattle do not display signs of Lyme disease; those that do may have lameness, painful or swollen joints, fever, laminitis, or weight loss. A skin rash may be present on the udder of infected cows. Bb has been found to exist in urine and colostrum of infected cattle; therefore, the possibility of transmission between cows should be considered. The Lyme bacterium has also been found in blood, milk, synovial fluid, and spontaneously aborted fetal tissue. Bb can survive in frozen milk, but is killed during pasteurization.
Infected horses generally do not have a fever, but may have lame or stiff joints, laminitis, depression, or refuse to eat. This bacterial infection may be a cause of moon blindness or loss of vision. There have been reports of spontaneous abortion and encephalitis in horses infected with Bb. Neurologic signs include head tilt, difficulty swallowing, or aimless wandering. Transplacental transmission occurs. Colts born to infected mares have displayed birth defects. Many horses may be infected with the spirochete, but display no symptoms.
PROTECTING YOUR PET
1. Apply tick-killing chemicals to your animals in order to protect them from disease spreading ticks. Sprays and dips containing permethrins and pyrethrins kill ticks on dogs, cats, and horses. Precautions should be taken when applying insecticides as some animals may be sensitive to the chemicals. Follow the manufacturer’s instructions.
It is a good idea to wear rubber gloves during application. Tick collars will help discourage ticks from attaching to your pet(s). Never apply multiple repellents on your pet. A mixture of different chemicals on your pet could make the animal very sick.
2. Take precautions to guard against ticks when entering tick habitat, such as grassy, shrubby, wooded, or beach grass areas. Cut/mow grassy areas regularly to reduce tick habitation.
3. Treat the environment with insecticides designed specifically for ticks. To avoid contaminating water, experts recommend spraying at least 75 feet away from a well.
4. Conduct frequent Tick-Checks! Examine animals closely in order to detect embedded ticks.
5. Remove attached ticks properly and promptly to reduce the chance of transmission of the LD bacterium. Place fine point tweezers around the tick’s mouthparts (the place where the tick is attached) and gently pull upwards until the tick detaches. Do not use your bare fingers!
Disinfect the bite site and tweezers after removal. Wash your hands. Place the tick, along with several blades of grass, into a small container (e.g. a clean screw-cap pill bottle or a zip-lock bag) for later examination. Call your veterinarian to determine if there is a local place where the tick can be tested. Label the container with: the date, name of pet, type of animal, owner’s name, address and phone number.
6. Have your animal(s) examined as soon as possible if you notice any symptoms of disease; the sooner a disease is diagnosed, the easier it is to treat.
7. Vaccines are available for dogs (in North America)
Lyme Disease Treatment in Pets
Lyme disease can be treated with antibiotics, because the disease is caused by a bacterium that is introduced to your pet through a bite from a tick carrying the disease.
Antibiotics will be taken for a long period of time and some times and may not be very effective if your pet has had the disease for a long period of time. Sometimes, your veterinarian can switch the antibiotics so see if that may cure the disease. But, if your pet does get bitten again, the disease can reoccur.
So, the best treatment for lyme disease is in the prevention. Ticks can be found in many different areas and are just waiting for the next warm body. Keeping your pets out of thick brush and high grass will help them from getting ticks, but there are many products on the market today that can in fact keep ticks off of your pets or kill these pests if your pet already has ticks.
Bathing your pet or grooming your pet can also help in Preventing ticks on the time you connect to your pet. After your pet has been outside in, comb him completely and check the skin. This can be a lengthy process when you dog or cat has long hair. But it is well worth the time.
If you have a tick on your pet better and is a movement, then you will be able to remove easily. Make sure you kill the tick. If the tick has attached it is very important to remove it properly. You can use tweezers or your fingernails [Tick Talk note – it is advisable not to use finegrnail – if they tick bursts then infection could be spread through the skin or eyes if you were t rub your eyes closely after – tweezers or tick tiwsters would be best!]. Grab the tick close to your pet‘s skin and pull straight out very firmly. Do not allow any of the contents from the tick on your skin or your pet‘s skin.
Effects of tick-borne disease on the canine immune system
The tick-borne diseases are caused by intracellular organisms, that is organisms that reside inside of cells in the animals they infect. Most are hemoparasites, inhabiting blood cells. Several can inhabit several different kinds of cells including those other than blood cells.
For whatever reason, perhaps their ability hide within the hosts cells, these organisms have profound effects on the immune systems of their host. They seem to cause immune system dysfunction, and often appear to suppress the hosts immune system at the same time they are triggering autoimmune reactions. Immune system depression manifests as lack of antibodies and vulnerability of the infected animal to secondary infections.
Autoimmune reactions are the hallmark of tick-borne disease. There may be autoimmune destruction of blood cells or blood cell progenitors in the bone marrow. Joints are inflamed and swollen and fluid tapped from affected joints has all the characteristics of autoimmune poly arthritis. Affected dogs may suffer from autoimmune disorders such as inflammatory bowel syndrome, myositis, and uveitis. Many affected dogs are reported to suffer from skin “allergies”, another indication of immune system dysfunction.
Indirect Testing Methods
Indirect antibody tests are most commonly used as they are more easily available from commercial testing laboratories and are less expensive. These tests analyze for the presence of antibodies against specific organisms. High levels of antibodies are believed to indicate active infection. The problem is how to interpret negative or low level positive results. A negative result is generally interpreted to mean the dog is not infected, although it could also mean the dog’s body simply has mounted no immune defense against the infecting organism. Low levels of antibodies may indicate a poor immune response against an active infection, or past exposure to the organism but no active infection.
Since antibodies may persist in the bloodstream for months or years following an infection, the presence of antibodies is not unequivocal evidence of active infection. The tick-borne organisms are notorious for causing immunosuppression and there is anecdotal evidence that infected dogs may have low or zero antibody levels. Low antibody levels or negative antibody test results are not conclusive evidence for lack of infection.
One probable reason for negative test results for dogs whose symptoms strongly suggest tick-borne disease is that the dog was not tested for the right species. Antibody tests are very specific for the exact species of tick-borne organism. Only a few species create “cross-over” problems, where antibodies from one species cause a false positive reading when testing for a different species. Typical test “panels” only test for a few species of the many tick-borne organisms that may infect dogs.
ARTHROPOD-BORNE INFECTIOUS DISEASES (by Acarus Labs, Bristol)
The diseases we work on are caused by bacteria (similar to E. coli) or much larger, more advanced organisms called protozoa (like amoeba or the agent that causes malaria). They are all transmitted by biting arthropods (ticks, fleas or flies).
Babesiosis is a tick-borne disease of companion animals, humans and food animals of worldwide significance. The disease is caused by protozoan organisms of the genus Babesia (sometimes called “piroplasms” due to their pear-like shape when seen within red blood cells). Of particular significance to us are the species B. canis and B.gibsoni, which can infect dogs, and B. felis, B. cati and B. pantherae which are found in cats.
The Babesias are protozoans, somewhat similar to those causing malaria and sleeping sickness. They have a complex two-host life cycle whereby they reproduce sexually in their tick host and asexually in mammals. The organisms replicate inside host red blood cells and cause a spectrum of disease ranging from no symptoms to a fulminant, acute disease, which may be fatal. Disease symptoms are usually due to the widespread destruction of red-blood cells with the concomitant release of haemoglobin and organisms into the blood stream. The major symptoms are fever, anaemia, haemoglobinuria (dark red, haemoglobin-containing urine), jaundice, lethargy and, in severe cases, acute collapse with multiple organ failure.
Bacteria of the genus Bartonella are found in the blood of many wild rodents and larger mammals, such as deer, throughout the world. In these natural hosts, infection with the bacteria does not appear to influence fitness. However, the transfer of these bacteria to domestic animals and humans can result in disease.
Bartonella appear to be transmitted from one animal to another by a range of biting insects, particularly fleas, although ticks have also been implicated. The disease can also pass, to humans at least, by direct inoculation e.g. by scratching or biting by heavily infected animals (thus giving rise to “cat scratch disease” a problem in immuno-compromised humans).
Bartonellosis (infection with Bartonella) is largely an infection of cats where it causes a wide spectrum of problems dependent on the underlying health of the animal, although current work is investigating its association with disease in other companion animal species. It appears that many animals carry Bartonella but remain symptomless. When stressed or immuno-compromised cats may develop fever, anaemia, heart and liver problems and neurological signs.
Borreliosis (sometimes known as Lyme disease) is caused by bacteria called Borrelia. Several species of this organism exist in Europe and all cause disease when transmitted to dogs and humans (and, less commonly, to cats, and horses). These organisms are adapted to live in rodent and wildlife reservoirs in which they cause no apparent problems. When ticks which harbour the organisms bite an animal, the bacteria are transmitted into the host with tick saliva and multiply in the bloodstream.
It appears that only certain types of ticks (known as Ixodes) can transmit Borrelia. Unfortunately the most common UK tick, the sheep tick (Ixodes ricinus), is one of these.
In humans the typical disease progression is a red rash around the tick bite which resolves and is followed by flu-like symptoms and arthritis. In animals the rash is not usually observed and the first signs of illness are that the animal appears “off-colour”; this lethargy and anorexia is often accompanied by lameness due to arthritic changes in the joints.
The infection is managed with antibiotic therapy but prevention is better than cure – evidence suggests that the ticks do not infect their host for 24 to 72 hours post-attachment. Removal of the ticks in this time frame should forestall the disease as would use of an effective acaricide (i.e. tick-killing preparation).
Ehrlichiosis is caused by a small bacterium (a rickettsia) from the genus Ehrlichia. These bacteria are predominantly passed from animal to animal by ticks in a similar manner to the transmission of Lyme disease. Once in the bloodstream the bacteria invade white blood cells (or platelets) where they multiply.
The clinical manifestations of ehrlichiosis are very varied, ranging from general loss of condition with intermittent fever to more organ specific pathology such as arthritis or eye problems. There are two major types of Ehrlichia which differ in the type of white blood cells they infect. The monocytic Ehrlichia (generally E. canis) tends to give rise to a chronic disease, whereas the granulocytic Ehrlichia (E. phagocytophila) causes a much more acute disease with high temperatures, anorexia and reluctance to move in infected animals. Both types cause depletion of clotting factors in the blood resulting in severe haemorrhage in some cases.
Leishmaniasis is a disease caused by protozoans of the genus Leishmania, and is transmitted by biting sandflies. Once in the body the organism lives inside macrophages, cells of the immune system. The disease is a major human health problem in parts of Africa, The Middle-East, South America and is widespread in the Mediterranean basin. The disease is a bigger problem in dogs than cats and a lot of work is being carried out to see if dogs are a natural reservoir of the disease in some areas.
Dogs infected with Leishmania tend to develop a chronic, systemic disease with a variable course of development. The commonest symptoms are weight loss and lack of endurance, lymphadenomegaly (“swollen glands”) and skin disease, particularly around the eyes. If caught in the early stages the disease can be successfully controlled by chemotherapy, but the organism is good at hiding and so repeated courses of therapy may be necessary throughout the animal’s life.
PCR-BASED SURVEY OF TICK-BORNE DISEASES IN THE UK/IRELAND
European Society for Veterinary Internal Medicine, 2001
Department of Clinical Veterinary Science, University of Bristol, UK
Extracts of report below:
A PCR-based survey of UK/Irish dogs and cats was undertaken to obtain a preliminary picture of the distribution and presence/prevalence of tick-borne infections. Blood samples from 180 systemically ill animals (120 dogs and 60 cats) from 41 practices distributed throughout UK and Ireland were collected during September-October, 2000. The study was stratified according to clinical signs and each sample was tested by PCR for Ehrlichia, E. phagocytophila, Borrelia and Bartonella DNA.
Simple PCR targeting of genus- or species-specific regions of rRNA genes (Ehrlichia), housekeeping genes (citrate synthetase and gltA in Bartonella), virulence factors (ospA in Borrelia) or multicopy sequences (epank1 in E. phagocytophila) was used.
DNA of endemic tick-borne pathogens was detected in 6.6% of sick dogs and 5% of sick cats. Borrelia burgdorferi sensu lato was detected in 5 % and E. phagocytophila in 0.8 % of canine samples. In sick cats, 3.3% were infected with B. burgdorferi sensu lato and 1.6% were infected with E. phagocytophila. No samples were positive for Bartonella DNA using PCR. However, in a larger separate survey of cats studied here, 11% were positive for Bartonella henselae using culture.
Retrospective study of UK samples submitted for PCR diagnosis
A rapid PCR-based diagnostic service for arthropod-borne diseases in companion animals has been developed at the University of Bristol. PCR methodology used is as described for the PCR-based survey. Between January 2000 and May 2001, 100 blood samples from ill non-travelled UK dogs and cats were PCR tested. Of 89 samples tested, 6 dogs were positive for E. phagocytophila (6.7%). Of 68 tested for Borrelia, 2 dogs (3%) were positive and of the 66 samples tested for Bartonella, 2 dogs (3%) were positive.
These preliminary data suggest significant exposure of UK/Irish companion animal populations and possibly their owners, to infected arthropod vectors. Ehrlichia phagocytophila, Borrelia and Bartonella spp are human pathogens and companion animals may act as sentinels for human infection (10). In addition, the presence of E. phagocytophila infection in dogs and cats in UK and Ireland has been confirmed.
Molecular evidence of Borrelia infection in dogs is confirmed and is reported for the first time to our knowledge, in cats. The Borrelia genospecies involved in infection will be further characterised using restriction fragment length polymorphism analysis. Canine Bartonella infection is reported for the first time in Europe and the canine
Bartonella DNA will be sequenced.
Prevalence of selected infectious agents in cats in Ireland
Journal of Feline Medicine & Surgery
Volume 12, Issue 6, June 2010
1 University Veterinary Hospital School of Agriculture, Food Science & Veterinary Medicine, University College Dublin, Ireland
2 College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO., Ireland
Vector-borne bacterial and rickettsial agents and Toxoplasma gondii, are common organisms in cats. Some are potentially zoonotic or may be transmitted via blood transfusion. The current study investigated the prevalence of these agents in cats from Dublin, Ireland, for which no published data exists. Whole blood (n = 116) and sera (n = 83) samples were obtained from 121 cats. DNA was extracted from blood and assayed using polymerase chain reaction techniques for Anaplasma species, Bartonella species, Ehrlichia species, Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’, ‘Candidatus Mycoplasma turicensis’ and Rickettsia species. IgG and T gondii IgG and IgM serum antibodies were detected by enzyme-linked immunosorbent assay. DNA consistent with B henselae (3.4%), B clarridgeiae (0.8%), both Bartonella species (0.8%), C M haemominutum (12.9%), or M haemofelis (2.5%) was amplified from 24/116 blood samples (20.6%). Antibodies to T gondii and Bartonella species were detected in 28 (33.7%) and 22 (26.5%) of 83 sera, respectively.
Tick-borne disease on Irish farms – 23-04-2011
By Micheal Casey
Mícheál Casey from the Department of Agriculture’s Regional Veterinary Laboratory service, outlines the common tick-borne diseases affecting Irish livestock
Ticks are blood-sucking parasitic members of the Arachnidae – the same class of eight-legged arthropods as spiders. Diseases transmitted by ticks are a major cause of economic loss, disease and deaths in farmed animals worldwide.
Although there is only one species of tick that affects Irish livestock – the ‘castor bean tick’, Ixodes ricinus – it can act as a vector for a range of diseases. All references to ticks in this article refer to this tick.
Ticks have some fairly precise environmental requirements, especially when they leave the relative shelter of the base of the vegetation. They find a new host by ‘questing’, where they climb to the tips of the vegetation and grab onto any animal (or person) that passes.
They need mild and moist conditions for questing, which are provided in late spring and in autumn in a typical Irish year, resulting in clearly defined spring and autumn peaks in tick-borne diseases.
On some farms the ticks have become adapted to one or the other season, while on other farms both peaks are seen.
This disease is caused by a bacterium (Ehrlichia phagocytophila) and is normally mild and transient. Although this is not commonly diagnosed, it is probably the most important tick-borne disease in Ireland.
Firstly, it is very common; so common, in fact, that most herds have a high level of resistance and most infection occurs in young and bought-in animals. As the name suggests, animals run a temperature for a couple of days, lose their appetite, they may cough a little and milk yield of cows drops significantly.
The reason for the significance of tick-borne fever is the brief but severe immunosuppression that accompanies infection with the organism. Affected animals are very susceptible to other infections at the time of infection, and vaccines for other diseases that are administered at the time of tick-borne fever infection will not take effect.
Furthermore, if the tick that infects the animal is also carrying one of the other tick-borne diseases, then infection is more likely and the ensuing disease may be more severe.
Tick-borne fever is a hidden but important factor in every other tick-borne disease.
This parasite, Babesia divergens, is carried by ticks and is capable of being transmitted from one generation of tick to the next, so a reservoir of infection can be maintained on pasture even when no livestock have grazed that pasture for several years.
Once inoculated into the bloodstream, the organism replicates rapidly in red blood cells, which are ruptured as each generation of the parasite emerges. Animals run a high temperature which then falls rapidly, often below normal, as the disease progresses. Affected animals become dull, lose their appetite, become slow and may have difficulty standing or walking as the disease progresses. The oxygen-carrying haemoglobin is released from the ruptured red blood cells and passes through the kidneys and out in the urine, giving it a characteristic reddish brown colour and giving the disease its common name – ‘redwater’. The heart races as the body tries to compensate for the loss of circulating blood cells.
Deaths can occur due to heart failure, kidney failure or anaemia, and blood transfusions may be required in the treatment of the most severely affected cases.
Drugs that prevent multiplication of the parasite are administered, but it is the effects of disease that are the most difficult to treat – anaemia, dehydration (and associated constipation).
One unique feature of redwater is the ‘reverse age immunity’ phenomenon. Calves are resistant to the disease until they are about six months of age. After that, the resistance an animal has to redwater in later life will depend on whether they were exposed to the disease as calves. Animals that have no resistance tend to develop a very severe form of the disease, and many farms routinely protect bought-in animals with a drug that gives protection for about four weeks. If this is given just before peak tick activity, there is a good chance that the animal will be bitten, infected and develop resistance without getting the disease, while protected by the drug.
Redwater seems to be decreasing in incidence and in severity in recent years. Partly, this is due to improved pasture management, which eliminates tick habitat. It also seems likely that the widespread use of Ivermectin-type products may have had an impact on tick productivity.
This is a disease of young lambs, which is caused by a common skin bacterium, Staphylococcus aureus. These bacteria are inoculated from the skin surface by the tick as it bites and get into the bloodstream causing septicaemia (blood poisoning). While the lamb’s blood carries the bacteria around the body, the tick will frequently be infecting the animal with tick-borne fever, which results in the bacteria ‘seeding’ the internal organs and tissues, especially the liver and the joints. A second septicaemia, often fatal, may occur at this stage. Affected lambs become slow and stiff and will die if untreated.
Q fever is caused by bacterium, Coxiella burnetti, and is very similar to tick-borne fever. Little is known about Q fever in Irish farm animals, largely because of the unavailability of diagnostic tests. It is known to occur here, and is tick-transmitted. It is likely to be behind some abortion outbreaks in sheep and cattle and may have an immunosuppressive role in a wide range of diseases
This bacterial tick-borne disease caused by Borrelia burgdorferi is strongly associated with deer, and the infection risk for humans and animals is highest in woodland and nearby pasture.
It is ‘one to watch’ as our wild and farmed deer population grows. It causes a fever and rash and can progress to cause central nervous system disease, arthritis and blood vessel damage in humans.
Again, little is known about the disease in Ireland, as it is rarely diagnosed, although blood testing shows that exposure to infection is common.
This is a serious and potentially fatal disease in humans, so it is very important to seek medical attention if any relevant symptoms are seen after a tick bite.
This virus causes encephalitis (brain inflammation) in sheep and is often fatal. It tends to occur in ticks in well-defined areas and is best controlled on affected farms by sourcing replacements from home-bred animals, or at least from within those areas.
A common feature of many tick-borne diseases is the strong, often life-long, immunity that results from infection. As a result, strong herd immunity develops, and very little disease tends to occur in stable, closed herds, even in heavily infested areas.
The exception here would be tick pyemia in lambs, where certain farms have a problem year after year unless they control the ticks.
Control of ticks requires the recognition and elimination of ideal tick habitat. Because ticks require mild, moist conditions, they are usually found at the base of dense vegetation. Ideal conditions for ticks occur where grass is growing through one or two years of dead previous growth (areas ungrazed for several years), and there is a moist decaying mat of old vegetation at the base of the sward. This is something to watch for when renting grazing land that may have been fallow for some time.
Control is achieved by minimising this phenomenon and by keeping animals fenced out of likely areas. Good pasture management and the rotation (where possible) of forage and grazing areas should minimise the amount of tick habitat.
The use of acaricides (chemicals that kill ticks) with residual effect will give protection against ticks for several weeks, and is a common practice, as a way to protect cattle or lambs during periods of peak risk.
However, preventing tick bites will also prevent the acquisition of immunity, so these animals will continue to be vulnerable once the protection offered by the acaricide wears off.
Another useful control measure is to source replacements within the herd, or at least locally, so that they will have been exposed to the range of tick-borne diseases that occur in that area.
Great care is needed when introducing animals from tick-free farms to areas where they will face a significant challenge, as these animals will have no immunity to tick-borne disease.
Dr. Bettina Wagner developed new techniques for testing for Lyme Disease that are more accurate, specific, and sensitive than previous tests.
“The bacteria that cause Lyme disease are particularly difficult to detect,” explained Dr. Bettina Wagner, Harry M. Zweig Assistant Professor in Equine Health, who teaches in the Department of Population Medicine and Diagnostic Sciences.
“After infection they tend to hide where they can’t be detected. They bury in the joints of dogs, causing arthritis or lameness. In humans and horses they also burrow into the nervous system, in the spine or even the brain, causing pain, paralysis, or behavioral alterations. By the time such clinical signs appear, the bacteria are usually not in circulation anymore.”
“We can now not only distinguish between infection and vaccination, but also between early and chronic infection stages,” Wagner noted. “That was not possible before. You were able to say whether an animal was infected, but not when it was infected, or how far the infection had developed.”
The test and information it provides can help veterinarians make advanced decisions about treatment. After the long treatment period ends, veterinarians usually conduct follow-up testing to see if it was successful. With the information the new multiplex test can give us about the stage of the disease in an animal, we know what to expect after treatment and can better measure its success.
Map of canine vector-borne disease in Europe
Canine vector-borne disease (geographic & seasonal distribution)
To buy a tick twister go to: http://ticktalkireland.org/ticktwister.html