Ticks carry a large number of diseases. Medicines are known for 15 diseases that are transmitted by ticks, and 7 of them can cause human pathologies. Among them, borrelez (Lyme disease) and tick-borne encephalitis. Over the past 30 years, the incidence of tick-borne encephalitis has increased 30-fold in many countries. The distribution of ticks and their physiology have changed. Now they are becoming active already in February-March. Some species can cause infection even in winter.
- Способ заражения и характеристика возбудителя 1. Method of infection and characteristics of the pathogen
- Симптомы и признаки патологии 2. Symptoms and signs of pathology
- Методы диагностики патологического состояния 3. Methods for diagnosing a pathological condition
- Методы лечения патологии 4. Methods of treatment of pathology
- Профилактика сезонного заражения 5. Prevention of seasonal infection
The method of infection and the characteristics of the pathogen
Tick-borne encephalitis is a disease caused by the introduction of a virus that affects the tissues of the animal's brain and spinal cord. It is caused by a flavirus (Flavivirus) - a lipid-coated microorganism containing a spiral of RNA, whose dimensions are 40-50 nm. The carrier and the main "vessel" supporting the life of the virus are ixodid mites. Infection of the dog occurs by a transmissible method - when the tick is sucked. The virus of tick-borne encephalitis is divided into three genotypes:
- Far Eastern;
- European (Western);
Each type of virus causes characteristic symptoms and damage. With the secretion of the salivary glands, the virus enters the bloodstream of the dog. There he is captured by macrophages. In them, the first phase of the virus multiplication takes place. A vacuole is formed around the absorbed virus, within which the virus replicates RNA and forms the envelope proteins of the virus (capsid).
The adult virions formed are assembled into groups surrounded by the vacuole and transported to the inner surface of the cell membrane. Tearing it, they go into the intercellular space. With the current of the lymph, viruses enter the lymph nodes, are introduced into the endothelium of the vessels, transported to the liver, the spleen - and there is its second reproduction.
The lymph flow carries the virus into the motor neurons of the spinal cord, localized in the cervical region, and along them the pathogen enters the cerebellum and the soft membrane of the brain. The incubation period in adult dogs is 1-2 weeks. When infection of puppies this period is reduced.
Symptoms and signs of pathology
Symptoms depend on the form of tick-borne encephalitis. Define the following forms of damage:
Symptoms do not appear immediately. The initial stage is hidden, then the following signs of illness appear in dogs:
- increase in body temperature to febrile values;
- behavior change - apathy or aggression;
- refusal of food;
- violation of gait;
- loss of coordination of movements;
- violation of the accommodation of the eyes, the appearance of strabismus;
- spasm of the larynx, change in the tone of barking;
- cramps, muscle paresis;
- decreased sensitivity of the dog's muzzle;
- tremor of the muscles of the body, especially in dogs of small breeds and puppies.
The European tick-borne encephalitis virus causes severe fever, which has a two-phase course. The first phase can last from 2 to 4 days. At this time, the virus is introduced and spread through the body of the dog. The first phase of fever is accompanied by nonspecific signs:
- feverish phenomena;
- complete refusal of food;
- muscle pains and spasms;
Then comes a temporary remission, which lasts 7-8 days. In 25-32% of dogs, the second phase causes symptoms of meningitis, encephalitis. The prognosis for the introduction of the Far Eastern strain of the virus is unfavorable. The Far Eastern virus causes brain damage in the form of meningitis, meningoencephalitis and focal lesions with a high probability of death.
It, mainly, causes paralysis of the front paws and respiratory musculature. This strain is most dangerous, as it causes severe consequences. There were registered the appearance of a new species of the Far Eastern strain, which caused hemorrhagic tick-borne encephalitis.
When the meningoencephalic form of the course of the disease, a diffuse or focal lesion of the nervous tissue is noted. Diffuse form is accompanied by:
- epileptic seizures;
- respiratory insufficiency;
- problems with swallowing, paresis of the muscles of the head;
- muscle weakness.
In focal encephalitis, the disease manifests as convulsions, muscular dystrophy, severe neurologic disorders. Since the symptoms of encephalitis can resemble different pathologies of the nervous system, then to refine the diagnosis it is necessary to conduct differential studies.
Methods for diagnosing a pathological condition
In addition to collecting anamnesis and physical research, the veterinarian appoints laboratory and hardware studies:
- clinical blood and urine tests;
- biochemical blood tests and bacussis;
- examination of cerebrospinal fluid;
- serological examination of blood;
- radiography of the skull;
- MRI or CT scan.
The possibility of conducting an in-depth study is not available in every veterinary clinic. To simplify the diagnosis, you can bring a live tick from a dog to a veterinary clinic. In the laboratory, the insect will be inspected for the presence of pathogenic microorganisms, since the tick may contain not only a tick-borne encephalitis virus. The insect is tested for the presence of the virus antigen, less often the PCR method detects fragments of the virus RNA. Research can be carried out even on fragments of the tick.
Symptoms of the disease are manifested when the number of viruses has grown to a certain level, which complicates treatment. Therefore, during the seasonal activity of ixodid ticks, it is necessary to apply infection prevention measures and carefully examine the dog after each walk. When a tick is found that has digested in the skin, it must be carefully removed and immediately seek medical help.
Methods of treatment of pathology
Since the disease causes a virus that develops inside the cells, the treatment presents a difficulty in choosing adequate methods. Antiviral therapy is carried out with the help of antibiotics, which can penetrate the hemoencephalic barrier. Isoniazid, Pefloxacin, Co-Trimoxazole, Rifampicin are used. Chloramphenicol.
These drugs have a strong toxic effect on the body of the dog, therefore, on the recommendation of the veterinarian appoint more sparing drugs, for example, Tienam, Tsefelim, Meronem, Pefloxacin, Ceftazidime. Symptomatic therapy includes:
- drugs that reduce temperature and pain;
- corticosteroids, to reduce the severity of neurological disorders - Methylprednizolon;
- drugs to reduce intracranial pressure - Diacarb, Mannitol.
A sick dog is given vitamin preparations, as the animals in the group B and C are lowering their levels. Ribonuclease may be used to treat dogs with neurological symptoms. Injections of the drug are carried out on the advice of a veterinarian. Injections of injections last 3-4 days. By this time, as a rule, the body temperature decreases.
With the meningeal form of encephalitis and fever, it is necessary to apply treatment aimed at detoxifying the body. The administration of saline solutions and buffer solutions is performed taking into account the state of the water-salt balance and the pH of the blood. With pronounced neurologic syndromes, corticosteroids are prescribed - Prednisolone. At the same time, the dog is given potassium salts, and a special diet with a high protein content is prescribed.
Tick-borne encephalitis can lead to bulbar disorders, which are expressed in the disorder of the function of swallowing and breathing. For relief of symptoms through the nasal catheter, moistened oxygen is injected. To improve the function of breathing, use the drug Cytochrome. Assign also courses of hyperbaric oxygenation. To eliminate the effects of hypoxia, prescribe the intake of sodium oxibutyrate and Seduxen. In the complex treatment of tick-borne encephalitis, a special gentle diet should be observed, especially in dogs with dyspeptic disorders.
Prevention of seasonal infection
To exclude the possibility of infection, the dog must be protected before walking. To do this, apply special acaricidal drops on the withers, sprays. But it should be remembered that the action of insecticides begins in a few hours, so applying the funds just before the dog's walk does not protect it from attacking ticks. As a barrier method, special collars are used. They scare off ticks. But after each walk it is recommended to conduct a thorough examination of the animal. Inspect zones with the most thin skin - behind the ears, under the paws, on the belly.
If a tick is found in the skin of a dog, it can not be lubricated with oil, since the fat only "deafens" the insect. It is better to drop on the parasite with alcohol, and then gently "unscrew" it from the skin. The site of the bite is disinfected and immediately appealed for help, since the tick can carry not only tick-borne encephalitis, but there is no effective vaccine for dogs from diseases transported by ticks.