Second, the characteristics of infectious diseases:
1. Caused by specific pathogenic microorganisms;
Infectious and epidemic;
3. Infected organisms have specific reactions;
1. Resistant animals can obtain specific immunity;
⒌ It has characteristic clinical manifestations;
6. It has obvious epidemic law; (Periodic, seasonal)
Three, the development stage of infectious diseases (the course of infectious diseases):
1. incubation period; 4. Precursor period; 3. Obvious (onset) stage; 4. Transition period (grey recovery period)
4. A Class I infectious disease refers to a disease that is seriously harmful to people and livestock and requires urgent and severe compulsory prevention, control and extermination measures.
5. A kind of epidemic situation includes: foot-and-mouth disease, swine vesicular disease, swine fever, African swine fever, African horse plague, rinderpest, bovine contagious pleuropneumonia, bovine spongiform encephalopathy, pruritus, bluetongue, ruminant zoonosis, sheep pox and goat pox, highly pathogenic avian influenza and Newcastle disease.
Class II epidemic diseases: diseases that cause great economic losses and require strict control and eradication measures.
Three kinds of epidemics: refers to common and frequent animal epidemics that can cause great economic losses and need to be controlled and purified.
Six, the type of infection:
1. Exogenous and endogenous infection;
Simple infection, mixed infection, primary infection and secondary infection;
3. Dominant infection and recessive infection;
2. Local infection and systemic infection;
5. Typical infection and non-yellow infection;
The most acute, acute, subacute and chronic infections;
Once persistent infection and lentivirus infection;
Section II Basic Links in the Epidemic Process of Animal Infectious Diseases
1. Three basic links in the epidemic process of infectious diseases: 1. Source of infection; Transmission route; 3. Susceptibility of herds.
2. Source of infection: refers to the living animals in which pathogens live, grow, reproduce and excrete.
Sources of infection include: sick animals and pathogen carriers.
4. Transmission route: The route through which pathogens invade other susceptible animals in a certain way after being discharged from the source of infection is called transmission route.
5. Transmission routes include: horizontal transmission and vertical transmission.
6. horizontal transmission: Infectious diseases spread horizontally between groups or individuals. Including direct contact propagation and indirect contact propagation.
7. Direct contact transmission: refers to the mode of transmission caused by direct contact between infected animals and susceptible animals without any external conditions.
8. Indirect contact transmission: The way in which pathogens infect susceptible animals through vectors is called indirect contact transmission.
9. Indirect contact transmission includes air transmission, contaminated feed and drinking water, contaminated soil and living media transmission.
X. vertical transmission: that is, vertical transmission from parents to offspring. Including placental transmission, egg transmission and birth canal transmission.
1 1. focus: the area where the infectious source and its discharged pathogens exist is called the focus. Including the source of infection, contaminated objects, houses, pastures, activity places, as well as suspicious fauna and storage hosts suspected of being infected within this range.
Twelve, according to the size of the epidemic, can be called the epidemic or epidemic area. Usually, a lesion consisting of a small lesion or a single source of infection is called a lesion. When a number of epidemic areas are connected into pieces and the scope is large, they are called epidemic areas.
Natural focus: The place with natural focus disease is called natural focus. Natural focus diseases refer to infectious diseases in which pathogens can be replaced from generation to generation without people or livestock.
Fourteen Manifestations of epidemic process of infectious diseases: sporadic, endemic, epidemic (outbreak) and epidemic situation.
15. seasonality of epidemic process: some animal infectious diseases often occur in a certain season, or the incidence rate increases obviously in a certain season.
Sixteen. Reason for seasonality: 1. The influence of seasons on the existence and spread of pathogens in the external environment; The influence of seasons on life media; 3. The influence of seasons on animal activity and resistance.
17. Periodicity of epidemic process: Some infectious diseases can be epidemic again after a certain interval. This phenomenon is called the periodicity of infectious diseases.
18. Factors affecting the epidemic process: natural factors, social factors and feeding management factors.
Section 3 Animal Epidemiological Investigation
1. Incidence rate: refers to the percentage of animals with clinical symptoms in a certain period of time.
2. Mortality rate: refers to the percentage of 9 sick animals that died in a certain period of time to the total number of animals in this group.
3. Mortality rate: refers to the percentage of the number of sick animals that died in a certain period of time in the sick animal population.
4. Steps and contents of animal epidemiological investigation: 1. Epidemic situation of diseases; Investigate the source of the epidemic; 3. Investigation on the ways and means of transmission; 2. Local conditions.
Section 4 Diagnostic Methods of Animal Infectious Diseases
1. Diagnostic methods of animal infectious diseases include: 1. Clinical comprehensive diagnosis; 2. Laboratory diagnosis;
Second, the clinical comprehensive diagnosis methods include: epidemiological diagnosis; Clinical diagnosis; Pathoanatomical diagnosis.
Third, laboratory diagnosis includes: ① pathological diagnosis; ② Microbiological diagnosis; ③ Immunological diagnosis; ④ Molecular biological diagnosis.
4. Microbial diagnosis includes: collecting diseased materials; Smear and microscopic examination of diseased materials; Isolation, cultivation and identification; Animal inoculation test.
5. Immunological diagnosis includes: serological test; Allergy.
Six, serological diagnosis includes: agglutination reaction, neutralization reaction, precipitation reaction, complement fixation reaction, immunofluorescence antibody test, immunoenzyme technology, etc.
Seven, molecular biological diagnosis includes: PCR technology, nucleic acid probe technology, DNA chip technology, etc. /*
Section 5 Comprehensive Epidemic Prevention Measures for Animal Infectious Diseases
1. The principle of epidemic prevention work is: 1. Establish and improve veterinary epidemic prevention institutions at all levels, especially at the grassroots level, to ensure the implementation of veterinary epidemic prevention measures; 1. Establish, improve and strictly enforce veterinary laws and regulations; 3. Implement the policy of "prevention first".
II. Basic contents of epidemic prevention work: 1. Preventive measures in peacetime; 2. Fire fighting measures in epidemic situations.
Three, the usual preventive measures include: 1. Strengthen feeding management, do a good job in sanitation and disinfection, and enhance the disease resistance of livestock. Carry out the principle of self-reproduction and self-support; Formulation and implementation of regular vaccination and replanting plans; 13. Kill insects, rodents and birds regularly, and treat the feces harmlessly; 4. Do a good job in quarantine; 5. Strengthen joint defense work.
4. Fire fighting measures in epidemic situation: 1. Timely discover, diagnose and report the epidemic situation, and notify the surrounding units to do a good job in prevention; 2. Quickly isolate sick animals and carry out emergency disinfection of polluted places. If a harmful epidemic occurs, comprehensive measures such as blockade should be taken; 3. Implement emergency immunization and timely and reasonable treatment for sick animals; 4. Strictly deal with the dead animals that have been eliminated.
5. Comprehensive epidemic prevention measures for animal infectious diseases include: 1. Epidemiological reporting and diagnosis; 1. Quarantine; 3. Isolation and blockade; 4. Disinfect and kill insects, mice and birds.
Six, when the discovery of important legal infectious diseases, must quickly report the epidemic situation to the superior, and notify the neighboring units and relevant departments to pay attention to prevention work.
Seven, when the sudden death of animals or suspected infectious diseases, should immediately notify the veterinarian. Before the veterinarian arrives or makes a diagnosis, the following measures should be taken: isolate the animals suspected of infectious diseases and assign special personnel to manage them; Disinfect the places where sick animals have stayed and the polluted environment and utensils; Keep the dead bodies of sick animals intact; Don't kill them hastily, and don't eat the skin, meat and internal organs of sick animals.
Quarantine: refers to the inspection of animals and their related products and articles for diseases or pathogens or antibodies by various diagnostic and detection methods. The purpose is to find out the source of infection, cut off the route of transmission and prevent the spread of epidemic diseases.
Nine, isolation: sick animals, suspected infected animals, assumed healthy animals.
Suspected infected livestock: no symptoms were found, but there was obvious contact with sick livestock and their polluted environment. Assumed healthy livestock: other susceptible livestock except sick livestock and suspected infected livestock in the epidemic area.
Eleven, China's "Animal Epidemic Prevention Law" stipulates that when it is diagnosed as an epidemic disease or a newly discovered infectious disease of livestock in the local area, it should be blocked. The principle of "early, quick, strict and small" should be grasped in the implementation of the blockade.
According to the purpose of disinfection, disinfection can be divided into preventive disinfection, temporary disinfection and terminal disinfection. Disinfection methods include mechanical cleaning, physical disinfection, chemical disinfection and biological thermal disinfection.
Thirteen, commonly used chemical disinfectants are: sodium hydroxide, lime milk, bleaching powder, sodium dichloroisocyanurate, peracetic acid, Lysol, Chlorhexidine, bromogeramine, chlorhexidine, disinfectant, domiphen, double-chain quaternary ammonium salt, ethylene oxide, formalin, mycotoxin, etc.
Fourteen, the commonly used insecticidal methods are: physical insecticidal method, biological insecticidal method and drug insecticidal method.
Fifteen, commonly used pesticides are:
(1) organophosphorus pesticides: trichlorfon, dichlorvos, fenthion, malathion, parathion, phoxim, etc. It is characterized by small dosage, quick poisoning and easy decomposition in the environment. However, it is highly toxic and has residues, which is harmful to people and animals.
(2) Pyrethroid insecticides: pyrethroids, etc. It has the characteristics of broad spectrum, high efficiency, quick knockdown, short effect, low toxicity and low dosage, and is effective against drug-resistant pests.
⑶ Insect growth regulators: juvenile hormones, insect growth regulators, etc. Its characteristics are no environmental pollution and no harm to people and animals.
⑷ Wall repellent: dimethyl phthalate, DEET, etc.
Drug prevention: In order to control some epidemic situations, some safe drugs are added into the feed and drinking water of the herds for collective prevention.
Seventeen, the principles and methods of drug prevention:
(1) Choose the right medicine. (Generally, conventional drugs are commonly used as first-line drugs, and specific drugs can be selected when the disease prevention goal is clear.
⑵ Strictly control the types, dosage and usage of drugs.
⑶ Grasp the time and opportunity of medication, and be regular, intermittent and flexible.
(4) Shuttle medication and regular dressing change. (a drug can be considered for replacement after continuous use for about one year.
5] Pay attention to the uniform mixing of drugs after administration, especially the artificial blocking of materials in small farms. It is more reliable to adopt a step-by-step mixing method from less to more. When administering drugs with water, attention should be paid to fully dissolving the drugs.
Treatment principles of infectious diseases: early treatment, treating both symptoms and root causes, combining specificity with nonspecific, and combining drug treatment with comprehensive measures.
Nineteen, the principle of therapeutic medication: pay attention to the indications of drugs, rational use, targeted; To master the dosage, we should not only use enough drugs to ensure the curative effect, but also prevent excessive poisoning; The course of treatment should be sufficient to avoid changing the medicine once a day, otherwise the medicine will not reach the effective concentration in the blood and it will be difficult to obtain the due curative effect; Antibacterial drugs should be replaced within a certain period of time, and it is not advisable to use a drug for a long time to avoid producing drug-resistant strains; We should not only pay attention to the combination of drugs, but also avoid waste or drug poisoning caused by too many kinds of drugs, or antagonism between drugs.
Twenty, infectious disease treatment methods include:
Pathogen therapy:
(1) special therapy; (2) antibiotic therapy; (3) chemotherapy; (4) antiviral drug therapy;
2. Animal therapy:
(1) Strengthen nursing; (2) symptomatic treatment; ⑶ Group therapy.
2 1. Vaccination: In areas where some infectious diseases often occur, or where some infectious diseases are potentially dangerous, or where some infectious diseases are often threatened by neighboring areas, vaccination is called vaccination in order to prevent problems before they happen.
22. Immunization program: According to the epidemic situation of infectious diseases, animal health status and the characteristics of different vaccines in a certain area, farm or specific animal group, a vaccination plan is formulated for specific animal groups, including vaccination types, sequence, time, times, methods and intervals.
Twenty-three, emergency immunization: refers to the occurrence of infectious diseases, in order to quickly control and put out the epidemic situation, the epidemic area and threatened area has not yet been sick of livestock emergency unplanned immunization.
24. Passive immunization: refers to the artificial transfusion of immune serum or serum of animals recovered from natural diseases to non-immune animals, so that they can gain resistance to a certain pathogen.
Twenty-five, immunization methods: subcutaneous, intradermal, intramuscular injection or skin prick, eye drops, nasal drops, spray, oral and other different vaccination methods.
Twenty-six, immune preventive measures:
1. Vaccination should be carefully planned;
4. Attention should be paid to the reaction of vaccination;
3. The combined use of several vaccines;
4. Reasonable immunization procedures.
Twenty-seven, formulate immunization plan should consider the following aspects:
Prevalence and severity of endemic diseases;
Maternal antibody level;
3. Residual antibody level caused by the last immunization;
Immune response ability of livestock;
5. Types and characteristics of vaccines;
6. Ways and means of immunization;
Coordination of various vaccines;
⒏ Effects on animal health and productivity.
Twenty-eight, reaction after vaccination:
Normal reaction: refers to the reaction caused by the characteristics of the product itself, and its nature and reaction intensity vary with the product.
4. Serious reaction: The number of animals that are serious or react exceeds the normal proportion. (The reason is: the quality of biological products is poor; Improper use methods, such as excessive inoculation dose, incorrect inoculation process, wrong inoculation route, etc.
[13] Complications: refer to reactions different from normal reactions. (mainly including: hypersensitivity-serum sickness, anaphylactic shock, allergic reaction; Spread to systemic infection; Induce latent infection.
Twenty-nine, factors affecting the immune effect of vaccine
1. vaccine factor; Storage and transportation of vaccines; 3. Immunization procedures; 4. Immunization method; 5. Animal factors.
Second, * * * is sick.
1, overview of foot-and-mouth disease
Foot-and-mouth disease is an acute, hot and highly contagious infectious disease caused by foot-and-mouth disease virus. Its clinical feature is the formation of blisters and rotten spots on the skin of oral mucosa, lower limbs and breasts. Adult animals often take a benign route, and young animals often have a higher mortality rate due to myocardial injury. In China, this disease is commonly known as "aphtha" and "hoof abscess".
Pathogenic foot-and-mouth disease virus belongs to the genus of foot-and-mouth disease virus in MicroRNA virus family. Foot-and-mouth disease virus is divided into seven serotypes, namely, A, O, C, SAT 1, SAT2, SAT3 (South Africa 1, 2, 3) and Asia I (Asia I). There is no cross-immunity among serotypes, but there is no difference in clinical symptoms among serotypes. Each serotype contains several subtypes, and there is only partial cross-immunity between subtypes of the same type. Foot-and-mouth disease virus (FMDV) is easy to mutate in epidemic process and immunized animals, that is, antigen drift, so new subtypes of FMDV often appear. There are more than 80 subtypes of foot-and-mouth disease, of which China is mainly Type A, Type O and Asian Type I, while Europe is Type A and Type O, of which Type O is the most common type.
The suckling mouse is very sensitive to this virus and is the best experimental animal. Generally, guinea pigs aged 3-5 days (or 7- 10 days) were inoculated subcutaneously or intraperitoneally, and died within 16-30h.
This virus is particularly sensitive to acids and bases. 2% ~ 4% sodium hydroxide, 3% ~ 5% formalin solution, 5% ammonia water, 0.2% ~ 0.5% peracetic acid or 5% sodium hypochlorite are all good foot-and-mouth disease virus disinfectants.
Under the natural conditions of epidemiology, foot-and-mouth disease virus can infect many animals, among which Artiodactyla is the most susceptible, and the susceptible order is cattle, cows, pigs, sheep, deer and camels. The susceptibility of young animals is greater than that of old animals.
Sick animals and poisonous animals are the main sources of infection of the disease.
Foot and mouth disease (FMD) is a highly contagious disease. Once it happens, it is often popular, especially in pastoral areas.
The epidemic of foot-and-mouth disease has a certain periodicity, and the disease has no strict seasonality. For example, the epidemic characteristics in pastoral areas are often manifested in late autumn, intensified in winter, eased in spring and basically subsided in summer. This seasonal performance is not obvious in agricultural areas.
clinical symptoms
The incubation period of cattle is generally 2 ~ 4 days, and the longest is about one week. The body temperature of sick cattle is as high as 40 ~ 465438 0℃, salivation occurs, blisters appear in the mouth, and the blisters burst to form red erosion. After the bubble burst, the body temperature dropped to normal. Blisters appear on the soft skin between the toes and the crown of the hoof, which quickly burst and eroded. The sick animal was unsteady and limping. Sometimes blisters will appear on the nipple skin, which will soon burst to form rotten spots.
The disease is generally benign, and the mortality rate is generally less than 3%; Malignant foot-and-mouth disease, the mortality rate is as high as 20 ~ 50%, which is mainly caused by virus invading myocardium, especially calves. Pregnant cows will miscarry.
The incubation period of sheep is about one week, and the symptoms are almost the same as those of cattle, but the infection rate is low.
The incubation period of pigs is 1 ~ 2 days, and the clinical symptoms are very typical. The main feature of sick pigs is hoof blisters, and the oral mucosa forms small blisters or rotten spots. If there are blisters on the nipples of nursing sows, the whole litter of piglets will get sick, mostly due to acute gastroenteritis and myocarditis, and the mortality rate can reach 100%.
Blisters, rotten spots and ulcers can be seen in the mouth, hoof, chest, throat, trachea, bronchus and gastric mucosa of diseased animals. Hemorrhagic inflammation can be seen in abomasum and mucosa of large and small intestine in ruminants. There are gray-white or yellowish spots or stripes on the myocardium, which is called "tiger spot heart".