One of the most dangerous diseases is malignant catarrhal fever in cattle. It is of viral origin and is manifested by inflammations on the conjunctiva, bronchi, lungs, and mucous membrane of the gastrointestinal tract, disabling the central nervous system of the animal. Today the disease is not fixed often, and only a few individuals usually suffer from it. Pathology spreads massively only in the cold season and with reduced immunity of the animal.
The cause of the disease
For the first time, malignant catarrhal fever (GCG) was mentioned by scientists in the middle of the XIX century. The disease is characterized by outbreaks in limited areas.
The culprit in the development of pathology in cattle is the DNA herpes virus. The exact pathways of the pathogen have not yet been studied. It is only known that it is not transmitted through saliva and urine, but is excreted with mucus from the eyes and nasal cavity. The fever pathogen particles are able to pass through the placental membrane.
The virus is released from infected animals, but is not transmitted even in the case of close contact with healthy individuals. Scientists have found that the virus can always be in the sheep. Therefore, it is not recommended to keep them with cattle. Cold wet weather, insufficient feeding, lack of vitamins and micronutrients contribute to the outbreak of the disease.
After registering the first case of pathology, veterinarians usually secrete about 1-2 diseased individuals each day. At the beginning of an outbreak, animals get much harder and die 100% of the time. By 40-50 days the disease passes much easier.
The disease is recorded in animals around the world, and in Russia was identified in 1873.
Susceptibility of cattle to the virus
In the natural habitat of CKD is found in cows and bulls. Domestic buffaloes also suffer. It is believed that the disease bypasses such animals as camels and African buffalo. There were cases of fever in goats and pigs. Through experiments, it was possible to infect guinea pigs, mice, rabbits with the virus. But in the household, pathology is recorded only in cattle.
Adults are most susceptible to fever. In young cattle, it is much less common. Perhaps the cause is colostral immunity, which appears in newborns during the first 2 days of life.
Usually, the disease occurs in animals aged 1 to 4 and from 8 to 10 years. In the latter case, the fever will be much harder. It has been established that bulls are sick more often than cows.
Pathological changes in individuals
The corpse of an animal is usually smeared with feces, and dried pus is observed around the nasal passage. The coat is raised, the fetid mucus often flows out of the mouth. After malignant fever, the corpse decomposes very quickly. An autopsy of the animal shows the following changes:
- heart muscle flabby;
- kidney point hemorrhages;
- lymph nodes inflamed and enlarged;
If the disease has spread instantly, then the above changes are minor. In animals, mucosal edema, inflammation of the lymph nodes and flabbiness of the heart muscle are observed.
The oral mucosa of the livestock reddens, areas of necrosis appear on it. In the nasal passage are observed pus and fibrinous films formed under the influence of infection and toxins. Brain membranes noticeably swollen, covered with accumulated blood.
How to diagnose a disease
Veterinarians diagnose malignant catarrhal fever in cattle with the help of the clinical picture, which is quite characteristic. In animals, the cornea becomes cloudy, and the mouth becomes inflamed. To confirm the diagnosis should conduct laboratory studies. Professionals need to understand whether the cattle have contacted the sheep and to track the number of diseased individuals.
An inexperienced veterinarian may confuse fever with other diseases that often occur in cattle. For example:
- foot and mouth disease;
- viral diarrhea.
Foot and mouth disease and plague spread very quickly, which is not the case with fever. Rabies can be eliminated if the animal is not aggressive. The last two diseases are detected only on the basis of serological and bacteriological studies. Therefore, it is necessary to take the blood of an animal for analysis as soon as possible.
Pathogenesis of viral pathology
The mechanism of development of malignant catarrhal fever in livestock has not been studied enough. Some scientists believe that it has an association with autoimmune diseases. Immediately after infection of the animal, the pathogen of pathology penetrates the bloodstream and begins to spread through the lymph nodes, the spleen. Then he finds himself in the brain and internal organs of cattle.
Against the background of the pathological process, perivascular tissue infiltration begins. In the first stage of the disease, the animal appears disseminated non-purulent encephalitis. It causes cortical inhibition in the central nervous system. As a result, the brain suffers greatly. For 2-3 days the virus infects the organs of the digestive system, bronchi, inner lining of the eyes. The inflamed epithelium is deadened, numerous erosions, ulcers appear.
The clinical picture of the disease
In an infected animal, the temperature quickly rises and a strong fever begins. Individuals feel oppressed, become fearful. Under the influence of fever cows give less milk. Then there are symptoms of a violation of the nervous system. Animals suffer cramps, tremble, their gait becomes shaky. Cattle constantly drink, but do not touch the food. Sometimes there is a coma.
On the second day of the development of the disease, inflammation begins. First, the mucous membranes of the nasal and oral cavities are affected. Then the eyes become inflamed and purulent discharge appears. Cattle poorly tolerated light, she begins tearing, ulcers appear on the cornea.
From the nasal passage of cattle is actively secreted mucus, which after a few hours becomes purulent. After inflammation of the larynx, the animal suffers asphyxiation symptoms, lungs and bronchi suffer. Croupous pneumonia develops, causing a strong, painful cough.
Symptoms of the late stage of the disease
Malignant catarrhal fever in the late stage is characterized by an uneven distribution of heat. Due to the strong inflammatory process, the head area of the individuals becomes hot. An animal can lose its horns if the inflammation goes to their bone basis. Therefore, during the illness of the cattle is not recommended to bind by the horns.
Constipation, which is formed in the initial stage of the disease, goes into diarrhea. In a feces films of fibrin, pus appear. In females labia increase in size, and the vaginal mucosa swells strongly and becomes covered with ulcers.
During fever, the urinary tract of animals is often affected, and cystitis or nephritis develops, which causes frequent urination and lumbar pain. A pregnant female has a miscarriage. The skin on the udder areas, back and neck is covered with eczema, the tissues on certain areas begin to die off. In the late stage, cardiac activity is inhibited, and the pulse increases to 100 beats per minute.
Treatment of diseased animals
There is no drug therapy for fever today. Sick individuals should be isolated in a separate room, ensure proper care and feed well-digested food. Suitable fresh hay, vegetables, grass. There should be enough clean water in the stall, which should be changed regularly.
Timely symptomatic treatment of the disease is carried out. Animals need to enter caffeine twice a day, to wipe a nose and an oral cavity. For these purposes, chamomile extract, potassium permanganate, and other aseptic preparations are used. Erosions and ulcers are smeared with a mixture of glycerin and lugol.
The eyes of diseased animals should be treated with boric acid (1%). During diarrhea use drugs Lysol, Ichthyol, possessing astringent and disinfectant properties. Secondary infection is suppressed with sulfonamide medicines and antimicrobial agents. During a fever, Eksid, Draksin, and Tarramycin are effective.
How to exclude the development of other pathologies
The disease is characterized by concomitant pathological processes. In order to prevent their development, the negative effect of the virus on the central nervous system must be reduced. It is this fact that causes the development of pathologies.
Veterinarians recommend giving strong alcohol to livestock. Drink 40 degrees need to water individuals for 4 days. The dose should not exceed 500 ml.
In addition, animals can be placed in a darkened room and make intravenous injections of alcohol. To do this, mix 200 ml of 96% alcohol with 25 g of glucose and add 300 ml of water. After the procedure, the individuals are immersed in sleep for about 50 minutes. It is necessary to make 4 such injections with a break in half a day. The highest efficacy of therapy is achieved if it is started maximum on the second day of the development of the disease.
Preventing the spread of the disease
Scientists have not developed a fever vaccine. Prevention is to prevent the spread of the disease. For this purpose, all rooms are disinfected and quarantined. Introduced restrictions on the import and export of animals from the village. A veterinarian examines livestock every day and when sick individuals appear, they are isolated from the rest.
Animal stalls are disinfected with a hot bleach, sodium or formaldehyde solution. All inventory also undergoes disinfection. The treatment is carried out immediately after the identification of the affected animal virus and continues daily until the complete elimination of the disease.
Leftovers and livestock manure need to be cleaned every day. They should be placed in a separate room and subjected to biothermal disinfection. This will eliminate pathogens of infectious diseases.
The quarantine for fever is removed two months after the last diseased animal was detected. Before this, the final procedure for the treatment with disinfectants is necessarily carried out.
Processing rules for hides and meat during quarantine
The presence of quarantine due to cases of malignant fever allows the slaughter of affected and suspicious individuals. But only if the cattle is not exhausted and the body temperature is normal. The slaughter of the animal is carried out in the sanitary zone under the supervision of a veterinarian.
Animal meat is conditionally suitable. It can be used in food, but only after pre-cooking or processing on canned food. Affected internal organs, tongue and head are disposed of.
The skins of dead or dead individuals must be disinfected. To do this, use a solution of soda (5%) and salt. On one part of the skins of livestock need to take 4 parts of the solution. The skin is disinfected throughout the day, stirring every 2-3 hours.
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