Cat Diseases – Feline panleukopenia
Feline panleukopenia, also known as feline distemper. It is a highly contact acute infectious disease caused by Feline parvovirus, FPV. This disease mainly occurs in young cats under 1 year old. Its main clinical features are fever, significant reduction of white blood cells, vomiting, diarrhea and hemorrhagic enteritis. It is an important infectious disease in cats.
Feline parvovirus (FPV) is a member of the Parvoviridae family (Parvoviridae). The particle diameter is 20-25nm, no envelope, and the viral genome is a single strand of DNA.
FPV can grow and multiply on the primary cells and passage cells of cat kidney, lung and testis, and produce cytopathic and nuclear inclusion bodies, which can be detected by hematoxylin-eosin staining. There is only one serum type of FPV virus, which can agglutinate porcine red blood cells at (PH6.0~6.4) 4°C and 37C.
FPV has strong resistance to ethanol, chloroform, acid-base, phenol and trypsin, and also has strong resistance to heat, but it is sensitive to formalin and hypochlorous acid, 0.2% formalin can The virus is inactivated within 24 hours, and the virus can preserve its infectivity for a long time under low temperature conditions or in 50% glycerol buffer.
The disease mainly infects cats and other cats (such as wild cats, tigers, leopards, bobcats, ocelots, etc.). Animals other than cats such as minks and ferrets can also be infected. Cats of all ages can be infected. Due to the individual immune differences in the cat population, the morbidity and mortality rates vary considerably. Kittens of 2 to 5 months of age have a special susceptibility to this disease, and the morbidity and death rate can reach 60% to 90%; the symptoms of old cats are much milder than kittens regardless of susceptibility and infection.
In the early stages of infection, the virus is excreted through the feces, urine, saliva, and vomit of sick cats, polluting the surrounding environment (such as cat food utensils, cat mattress materials, cages, etc.), making susceptible cats infect through the digestive tract after contact. During the acute phase of the disease (viremia phase), blood-sucking insects such as fleas and venom can transmit the disease. Sick cats still carry the virus for several weeks or more than a year after recovery, and can excrete toxins from their feces and urine, which is still a source of infection.
The disease mostly occurs in late winter and spring. The highest incidence is from January to March. Transportation stress, crowded cats, and mixed breeding of cats from different sources can promote the outbreak of the disease.
Viremia occurs in cats about 24 hours after being infected with the virus. The virus persists in the blood for about 7 days and gradually migrates to host cells. Feline parvovirus has a special affinity for the intestinal mucosal epithelium. It first selects the dividing cells and causes the destruction of the intestinal mucosal cells. Secondly, it invades the hematopoietic system, causes the suppression of lymphoid tissue and bone marrow, and causes a significant decrease in lymphocytes and neutrophils.
After a pregnant cat is infected, the virus can infect the fetus through the placental barrier and cause miscarriage. If the kitten is infected before or just after birth, FPV can invade the cerebellum and cause cerebellar atrophy.
The incubation period of this disease is 2 to 7 days, and the most acute type of patients died suddenly before the obvious symptoms appeared. Acute cases died within 24 hours. Before death, there were only general symptoms of poor spirits and loss of appetite. The course of subacute cases was 7-9 days. Common clinical cases belong to subacute cases. This type of case has the following clinical indications.
(1) Fever type: After the onset, the body temperature rises to about 40C, lasts for 24 hours, and then drops to room temperature. After 2 to 3 days, it rises to above 40 degrees again, showing a typical two-phase thermal type.
(2) Blood picture changes After the onset of sick cats, the white blood cells began to decrease. After the second body temperature rise, the white blood cells dropped to 2X10VL»20% of the cases fell to 0.2X10VL white blood cells, and in a few cases the white blood cells dropped to zero.
(3) The typical symptoms of sick cats are listlessness. Loss of appetite, loss of appetite and weakness during the second fever, lying still, staring without vision, protruding third eyelid, and a large amount of purulent secretions in the nasal cavity. Frequent vomiting and severe diarrhea. The vomit is some undigested food at the beginning, and later it is a pale yellow or pink liquid. Diarrhea is bloody stool with a special foul smell. The sick cat became dehydrated quickly, lost weight and died of heart failure . The case fatality rate is generally 60% to 70%, and the high rate can reach more than 90%. Miscarriage, premature delivery, stillbirth and fe
tuses with cerebellar hypoplasia can occur in pregnant female cats after infection. The course of the disease is 2 to 3 days, the longest is 4 to 6 days, and most of the cases without death after 7 to 8 days can recover spontaneously.
Small intestinal mucosa is congested, swollen, and diffusely bleeding. The contents of the intestinal cavity are yellow-red, watery and foul. The mesenteric lymph nodes are markedly edema, congestion and bleeding, and the cut surface is juicy and marble-like.
Increased ascites•Fibrinous pseudomembrane appears, and long bone red bone marrow is liquid or jelly-like changes. The liver is enlarged, the gallbladder is filled with thick bile, and the spleen is bleeding. Pulmonary congestion, bleeding, and edema.
Histological examination revealed degeneration, necrosis, shedding of intestinal gland epithelial cells, sparse bone marrow cells, megakaryocytes, and degeneration of intestinal lymphoid follicular epithelial cells.
Based on the epidemiology, typical dual-phase fever, frequent vomiting and severe diarrhea, combined with the significant leukopenia and characteristic pathological changes in routine blood tests, a preliminary diagnosis can be made, and the diagnosis requires an etiological diagnosis.
Parvovirus test paper rapid diagnosis method Take about 1g of sick cat feces into a clean and sterilized test tube, add about 5 mL of normal saline, and let it stand for 5 minutes with full vibration (or centrifugation). Take the test strip and insert the end with the arrow with the max line. In the stool supernatant (note that the stool level should not exceed the max mark line), take it out and place it on the table after about 15 seconds. Observe the result after 5 minutes. One red line is negative and two red lines are positive.
The disease is the most important infectious disease in cats and other feline animals. It mainly depends on vaccination to prevent its occurrence. At present, FPV cell culture formaldehyde inactivated vaccine and cat plague-rabies (FPV-RV) dual vaccine are widely used in China to prevent this disease.
(1) Specific therapy: In the early stage of the disease (during the period of viremia), inject anti-feline serum, 2 to 4 mL/kg body weight, intramuscularly or intravenously, once a day, for 3 consecutive injections.
(2) Heart-strength rehydration: Replenish compound sodium chloride 30-50 mL/kg body weight, add 50% glucose to make 5% intravenous infusion, once a day. Shengmai needle 2~4 mL, vitamin B, 0.5~1 mg mixed intramuscular injection. 1-2 times/d.