Ratpox-the main disease of laboratory animals

  Mousepox is a serious infection caused by mousepox virus that infects experimental mice. This disease is mostly fulminant, has a high mortality rate, and is harmful. The clinical manifestations are systemic or local skin diseases, swelling, ulcers, necrosis, and even loss of toes on the feet, legs or head, sometimes called infectious foot prolapse.

  1. The pathogen virus belongs to the symptom virus family, a subfamily of vertebrate symptoms, and belongs to the orthovirus genus. The type of nucleic acid is double-stranded DNA. The virus particle is brick-shaped and the nucleus is dumbbell-shaped. The virus mainly replicates in the cytoplasm of epithelial cells and forms viral inclusion bodies in the cytoplasm. The virus can grow on a variety of passage cells, including Vero, Hela and hamster kidney cells. The virus is highly resistant to 60% of bacteria in dry, cold and humid environments. You can disable Clomin. Oxidants, hypochlorite and chlorine chloride can inactivate the virus. 0.2% formaldehyde will destroy the infectivity of the virus.

  2. Epidemiology

  The source of this disease is mainly diseased and recessively toxic mice, which detoxify the surrounding environment through skin damage, feces and urine. The virus can enter the human body through skin wounds, and can also spread through the respiratory and digestive tracts. Infected animals appeared skin lesions characteristic lesions around day 10. Recovered mice will excrete toxins through the feces for a long time, which may be the main cause of infection. Both breeders and arthropods may be carriers of the disease and can be spread in many ways through artificial inoculation. The disease can occur throughout the year, improper feeding and management, disinfection, weak quarantine and quarantine systems all contribute to the outbreak. In recent years, it has become possible to directly inoculate experimental mice with viruses through tumor inoculation or transplantation.

  3. Clinical symptoms

  is clinically divided into the following three types of diseases.

  Acute lethality: common in rats that first developed the disease. Sick rats have rough hair, sluggish hair, lethargy, loss of appetite, and usually die within 4 to 12 hours.

  Subacute? Chronic transit: typical symptoms of foot hair loss. Sick mouse mouth, nose, face swelling, stains, watery eyes, four chains and tail swelling, serous exudate, tail and leg necrosis, and severe explosions, severe explosions and then fall off. Addicted to it in 2 days. This type can continue to die for a long time. Asymptomatic resistant type: Although the animal looks healthy and disease-free, the virus can still multiply in mice, become a poisonous animal, and become a new source of infection.

  4. Pathological changes

  Acute: Severe liver hemorrhage and necrosis. The liver can be enlarged with the naked eye, and due to acute inflammation and steatosis, the liver will turn slightly yellow. The spleen showed clear necrosis, red and acetabular necrosis, epileptic scars, and the spleen was white with a reddish-brown "mottled" appearance. Swelling of the duodenum, congestion, bleeding and whole intestinal necrosis. Inclusion bodies were found in liver cells and duodenal epithelial cells around necrosis. Subacute to chronic: Splenomegaly and lymphadenopathy can be seen. Skin lesions may show inflammatory edema, epithelial necrosis, ulcers, etc. Microscopic examination showed inclusions of epithelial cells. The types of cytoplasmic inclusion bodies are 2. Type A inclusion bodies are eosinophils and halos, which mainly exist in the skin epidermis and membranous epithelium of Mongolia. Type B inclusion bodies are basophilic and are found in many infected cells.

  5. Diagnosis

  Ratpox can be diagnosed by clinical signs, pathological changes, serological examination, virus isolation or examination of viral antigens in tissues. Histopathological diagnosis can be made by identifying characteristic necrotic lesions, discovering eosinophilic inclusion bodies and observing poxvirus under an electron microscope. Serological tests can be used to detect smallpox infection in mice. Hemagglutination inhibition test (HIA) used to be the standard diagnostic method, but now it uses a sensitive and specific enzyme-linked immunosorbent assay (ELISA) for rapid routine monitoring. .. Indirect immunofluorescence (IFA) is also very common. When invisible infection is suspected, they can be placed in rat colonies as designated animals to monitor susceptible mice without vaccinia virus strains (A, DBA, C3H, etc.).

  6. Prevention

  cannot cure ratpox. Contaminated rat colonies are prone to persistent or concealed infections and are difficult to remove. Therefore, it is necessary to use all rat colonies that are in contact with infected rats and contaminated breeding rooms, equipment and laboratory equipment. Chlorine needle sterilization or autoclave. After the facility was completely disinfected, a new disease-free population was introduced, feeding control was improved, a quarantine system was strictly implemented, serological testing was performed routinely, and sensitive sentinel animals were used in the experimental animal group. This is the basic measure for monitoring mousepox virus infection.