Canine distemper, commonly known as canine distemper, is a serious canine disease that mainly harms puppies. The pathogen is canine distemper virus. Sick dogs are characterized by biphasic fever, rhinitis, severe digestive tract disorders and respiratory inflammation. Encephalitis may occur in a few cases.
Cause:
Various secretions and excretions (nasal juice, saliva, tears, pericardial fluid, pleural effusion, ascites and urine) as well as blood, cerebrospinal fluid and lymph nodes of sick dogs Organs such as the human body, liver, spleen, spinal cord, etc. all contain large amounts of viruses, and they can be excreted to the outside world along with respiratory secretions and urine. Respiratory or digestive tract infection occurs when healthy dogs come into direct contact with sick dogs or through contaminated air or food. In addition to puppies being the most susceptible to infection, foxes and minks among fur animals are also very susceptible to canine distemper.
Symptoms:
The incubation period of canine distemper is 3-9 days. Symptoms vary and are related to the intensity of virulence, environmental conditions, age and immune status. The first symptom of canine distemper is an increase in body temperature, which lasts for 1-3 days. Then it subsides, much like the symptoms of a cold. But the temperature rises again after a few days, and the duration is uncertain. Tearing, redness of the conjunctiva, and eye secretions from liquid to mucopurulent may be seen. The nose is dry and nasal fluid flows out. It is serous nasal fluid at first and then turns into purulent nasal fluid. At the beginning of the disease, there was a dry cough, which later turned into a wet cough and difficulty breathing. Vomiting, diarrhea, intussusception, and ultimately death from severe dehydration and weakness.
Nervous symptomatic canine distemper mostly appears about 10 days after the above symptoms. Clinically, neurological symptoms frequently occur in cases of footpad keratosis and nasal keratosis. Symptoms vary depending on where the canine distemper virus attacks the central nervous system. The virus damages the brain and manifests itself as epilepsy, circling, abnormal standing posture, unsteady gait, ataxia, paroxysmal twitching of masticatory muscles and limbs and other neurological symptoms. The prognosis of this type of neurological canine distemper is usually: bad.
Canine distemper virus can cause eye damage in some dogs. Clinically, it is characterized by conjunctivitis and keratitis. Keratitis is mostly seen about 15 days after the onset of illness. The cornea will turn white. In severe cases, it may appear. Corneal ulcers, perforations, and blindness.
This disease has a high mortality rate in puppies, with the mortality rate reaching 80 to 90%. Symptoms such as pneumonia, enteritis, and intussusception may occur secondaryly.
Clinically, once the characteristic canine distemper symptoms appear, the prognosis is very poor. Especially unvaccinated dogs. Despite clinical symptomatic treatment, the progression of the disease is difficult to control, and most patients die from neurological symptoms and failure. Dogs that partially recover generally have varying degrees of sequelae.
Epidemiology
This disease can occur throughout the year, but is more common in winter and spring. The disease has a certain periodicity, with a pandemic occurring every three years. Dogs of different ages, genders and breeds can be infected, but underage puppies are the most susceptible. Purebred dogs and police dogs are more susceptible than native-bred dogs, and have severe disease reactions and higher mortality rates. The most important sources of infection for this disease are nasal and eye secretions and urine. It has been reported that dogs infected with canine distemper virus still excrete the virus in their urine 60-90 days later. Therefore, urine is a very dangerous source of infection. The main transmission route is direct contact between sick dogs and healthy dogs, or through air droplets. Respiratory tract infection. Once canine distemper is found in dogs living in the same room, no matter how strict protective measures are taken, the dogs living in the same room cannot be prevented from being infected.
Key points for diagnosis:
(1) Epidemic characteristics: This disease occurs frequently in the cold season (from October to April of the following year), especially in units or areas where dogs gather. Once the disease occurs in a group of dogs, it is difficult for other puppies to avoid infection unless they are under absolute isolation conditions. Nursing puppies rarely get sick because they can obtain antibodies from their mother's milk. Puppies aged 3 months to 1 year old are usually the most susceptible.
(2) Clinical characteristics: The body temperature is biphasic (i.e., the body temperature rises to about 4 amp; C at the beginning of the disease, lasts for 1 to 2 days, then drops to normal, and rises again after 2 to 3 days ); Respiratory symptoms appear when the body temperature rises for the second time (a few cases die at this time). The sick dog coughs, sneezes, serous to purulent nasal juice, dry nose, swollen eyelids, purulent conjunctivitis, and cornea often occurs in the later stage. Ulcers; large red spots, edema and purulent papules on the skin of the lower abdomen and medial thigh; frequent vomiting; initial constipation, soon diarrhea, feces with foul odor, sometimes mixed with blood and bubbles. In a few cases, transitional keratotic lesions of the skin on the soles of the feet and nose can be seen. About 10-30% of sick dogs have neurological symptoms (spasm, epilepsy, convulsions, etc.). The fatality rate of this disease can be as high as 30 to 80%. If mixed infection with canine infectious hepatitis and other diseases, the fatality rate will be higher. Because this disease is often mixed with canine infectious hepatitis and other diseases and secondary infections with bacteria, the symptoms are complicated. Therefore, only a preliminary diagnosis can be made based on the above symptoms alone. For the final diagnosis, the patient materials (conjunctiva, bladder, stomach, lungs, trachea, brain, and serum) must be collected and sent to the testing unit for virus isolation, neutralization test and other specific tests. examine.
Prevention and control measures:
(1) Regular vaccination: The canine distemper vaccine currently produced in my country is a cell culture attenuated vaccine. In order to improve the immune effect, the following immune procedures should be carried out. The puppies are immunized for the first time at 6 weeks of age, the second immunization at 8 weeks of age, and the third immunization at 10 weeks of age. From now on, immunization is performed once a year, and the dose of each immunization is two milliliters, which can achieve a certain immune effect. In view of the presence of maternal antibodies in the bodies of puppies under 12 weeks of age, which can significantly affect the immune effect of canine distemper vaccine, it is best to apply measles vaccine (canine distemper virus and measles virus) to puppies under 12 weeks of age. The specific immunization method is that when puppies are 1 month old and 2 months old, they should be immunized once with measles vaccine. The vaccination dose is intramuscular injection per dog. 1 ml (2.5 servings), and immunize with canine distemper vaccine when the dog is 12 to 16 weeks old. According to reports from some units, better immune effects can be obtained when immunized with this immunization program.
(2) Strengthen veterinary health and epidemic prevention measures, and each breeding farm should try its best to reproduce and support itself. During the epidemic season, it is strictly prohibited to bring personal dogs to areas where dogs gather.
(3) Timely isolation and treatment: Timely detection of sick dogs, early isolation and treatment, and prevention of secondary infections are the key to improving the cure rate. In the early stage of the disease, anti-canine distemper hyperimmune serum or serum (or whole blood) of dogs recovered from the disease can be injected intramuscularly or subcutaneously. The dosage of serum should be determined according to the condition and the size of the dog's body. Usually, 5 to 10 ml can be used to obtain a certain curative effect. There are reports that while treating with hyperimmune serum, the therapeutic effect can be improved by using anti-duling freeze-dried powder for injection. The usage method and dosage are as follows: before treatment, dissolve anti-duling with 20 ml of normal saline or water for injection. , 2 to 4 bottles of intravenous drip for medium-sized dogs, and the dosage can be reduced for dogs that are younger than 1 month old. Antivenom can also be injected intramuscularly. In addition, early application of antibiotics (such as penicillin, streptomycin, etc.), combined with symptomatic treatment, is of great significance in preventing secondary bacterial infection and in the recovery of sick dogs.
(4) Thoroughly disinfect kennels and sports venues: Kennels and sports venues should be disinfected with 3% caustic soda (also known as sodium hydroxide) solution or 10% formalin.
Treatment:
After clinical symptoms appear, a large dose of canine distemper hyperimmune serum can be injected to control the development of the disease. Giving a large dose of hyperimmune serum during the initial fever period of canine distemper can enhance the body's sufficient antibodies to prevent clinical symptoms and achieve the purpose of treatment. For canine distemper with obvious clinical symptoms and neurological symptoms in the middle and late stages of the disease, it is mostly difficult to cure even if the canine distemper hyperimmune serum is injected.
Symptomatic treatment: sugar replenishment, fluid replenishment, fever reduction, prevention of secondary infection, strengthening of feeding and management, disinfection of the kennel environment, etc., have a certain therapeutic effect on this disease.