Frequently Asked Questions About Gardnerella Infection in Foxes, Mink and Raccoon Dogs
1 How do you determine that a fur animal has contracted an infectious disease?
Answer: (1) Infectious diseases are all caused by pathogenic microorganisms, and each infectious disease has its own specific pathogenic microorganism. For example, canine distemper is caused by infection with canine distemper virus of the Paramyxoviridae family, fox encephalitis is caused by infection with canine adenovirus, and Aleutian disease of mink is caused by infection with Aleutian virus of the Parvoviridae family. Pasteurellosis is caused by infection with Pasteurella multocida, and this must be confirmed through pathogen isolation and identification, immunological diagnostic methods, and so on. (2) Infectious diseases are contagious and epidemic. Pathogenic microorganisms shed from the bodies of diseased animals can be transmitted to another healthy animal through different routes and can cause the same clinical symptoms. When conditions are suitable, within a certain period of time, the animal population within a certain range or a certain area becomes infected, resulting in large-scale spread and diffusion that forms an epidemic. (3) Infected animals have characteristic clinical manifestations. Most infectious diseases have characteristic symptoms of that disease as well as a certain incubation period and course. For example, the eye and nose changes and biphasic fever pattern of canine distemper; the abortion and empty pregnancy of Gardnerella vaginalis. (4) The infected animal body undergoes a specific reaction. This specific reaction occurs because, under the antigenic stimulation of the pathogenic microorganism, the body undergoes an immunological reaction and produces specific antibodies against that antigen, which can be detected through different immunological diagnostic methods such as agglutination reaction, agar diffusion test, counter immunoelectrophoresis, enzyme-linked immunosorbent assay, and so on. (5) Animals that survive the disease can acquire specific immunity. After an animal survives an infectious disease, it generally can produce specific immunity, so that the body will no longer be infected by that infectious disease for a certain period or for life.
2 After a fur animal contracts an infectious disease, what measures should be taken for effective prevention?
Answer: Once it is determined that a fur animal has contracted an infectious disease, first strictly isolate the diseased animals. Cages, boxes, floors, feeding and drinking utensils, gloves, and capture tools contaminated by the excrement and secretions of diseased animals should all be thoroughly disinfected. At the same time, promptly collect diseased materials from dead animals and send them for diagnostic identification as quickly as possible. After a certain infectious disease is confirmed, emergency vaccination of the whole group should be carried out immediately. For relatively safe inactivated vaccines, the dose can exceed 2 times the normal immunization dose.
For bacterial infectious diseases, while carrying out emergency vaccination (excluding live vaccines), or when there is no vaccine available for vaccination, select sensitive drugs and administer them to the whole group for prevention. For viral infectious diseases, antibiotics should be used to control secondary infections. For example, the respiratory system and digestive system are the most susceptible to attack, so drugs should be selected for treatment to reduce symptoms and alleviate the course of the disease. When necessary, hyperimmune serum should be used for specific treatment, while antiviral drugs should be selected for control. Other systemic therapies such as cardiac support, detoxification, and fluid infusion should all be considered for application.
It is strictly prohibited to casually dissect or discard dead and diseased animals everywhere. Carcasses of animals that died from infectious diseases must be deeply buried or incinerated. When the infectious disease has been brought under control, the epidemic has stopped, and no new cases appear, a final major disinfection of the animal farm should be carried out.
3 What factors can lead to the spread and epidemic of infectious diseases in fur animals?
Answer: After pathogens are shed by diseased animals, they can be transmitted to healthy animals in two ways. (1) Direct contact transmission. That is, without the participation of any external factors, pathogens are transmitted when diseased animals directly contact healthy animals. This mode of transmission includes mating, licking, and biting. For example, Gardnerella vaginalis infection is mainly transmitted through mating; rabies can usually be transmitted only when a diseased animal or diseased dog bites and introduces rabies virus into the wound along with saliva. (2) Indirect contact transmission. That is, with the participation of external environmental factors, pathogens cause infection in healthy animals through transmission vectors. Examples include canine distemper, parvovirus enteritis, pasteurellosis, and colibacillosis. Forms of indirect contact transmission include: transmission through the air, such as droplets and dust, with the respiratory tract as the portal of entry; transmission through contaminated feed and drinking water, mainly with the digestive tract as the portal of entry; transmission through contaminated soil, which generally does not occur in fur animals under cage-raising conditions; transmission through living vectors, such as pathogen- or virus-carrying mosquitoes, flies, ticks, dogs, rats, and humans.
4 How do you distinguish bacterial infectious diseases from viral infectious diseases in fur animals?
Answer: After a fur animal contracts an infectious disease, it is first necessary to clarify what pathogen causes it, which is very important for effectively controlling the infectious disease. Infectious diseases are usually caused by two types of microorganisms, namely bacteria and viruses. The basis for identification includes the following points: (1) Therapeutic diagnosis. For bacterial infectious diseases, treatment with appropriate antibiotics for a certain course significantly reduces symptoms and leads to recovery; for viral infectious diseases, antibiotic treatment is ineffective or can only relieve symptoms and cannot cure the disease. (2) Confirmation through laboratory diagnosis. By performing smear microscopy, isolation and culture, and physiological and biochemical identification on the carcasses of dead animals, bacterial infectious diseases can be confirmed; while viral infections require examination for "inclusion bodies," or immunological diagnosis, and when necessary, confirmation with the aid of an electron microscope. Viruses must be cultured in specific cells to grow, do not grow on artificial media, and individual virus particles cannot be seen under an ordinary light microscope.
It should be emphasized that sometimes viral infectious diseases and bacterial infectious diseases often occur as co-infections or secondary infections, and this must be considered by the examiner during laboratory diagnosis.
In addition, microorganisms such as mycoplasma and Eperythrozoon belong to neither bacteria nor viruses, and this must also be considered during diagnosis. At the same time, a comprehensive judgment should be made in combination with epidemiology, clinical symptoms, and pathological changes. Generally, after ruling out bacterial and viral infections, infectious diseases caused by other microorganisms should be considered.
5 After a fur animal contracts an infectious disease, why is emergency vaccination emphasized?
Answer: When an infectious disease occurs in fur animals, after the pathogen is identified through testing, for bacterial infectious diseases, although drugs can be used for control, the cure rate is limited; for viral infectious diseases, drug treatment can only control secondary infections. Emergency vaccination is the use of vaccines for specific immunization on the basis of an already confirmed pathogen. After the body produces specific antibodies, it can clear and neutralize the pathogen. Generally, vaccines can produce antibodies 5 to 7 days after vaccination, and the antibody titer in the body gradually rises. When the antibody level reaches a certain height, immune protection can be achieved. Usually 10 to 15 days after emergency vaccination, no new cases appear and the epidemic stops. If it is an inactivated vaccine, it can not only protect healthy animals but also provide a certain degree of protection for diseased animals, such as viral enteritis vaccine, pasteurellosis vaccine, and so on; if it is an attenuated live vaccine, it can only protect healthy animals, while for animals with symptoms or latently infected animals that already carry the pathogen but have not yet shown symptoms, it promotes worsening of symptoms or the appearance of symptoms. This is an inevitable result during emergency vaccination with live vaccines and is a normal reaction. But on the whole, it still protects most healthy animals. Animals infected during the incubation period will sooner or later show symptoms, especially for viral infectious diseases, which is unavoidable. For example, when canine distemper occurs in fur animals, chemical drugs cannot control it, and emergency vaccination must be carried out; otherwise, the scale of the epidemic will gradually rise, eventually leading to an uncontrollable situation.