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| Question | Answer |
| 1.Definition of infectious diseases, sources of infection, factors influencing infectious diseases (pathogen-host relationship, protection of the host, environmental factors) 1/2 | Definition: Infectious disease: (dict) a disease caused by the entrance into the body of organisms (as bacteria, protozoans, fungi, or viruses) which grow and multiply there Src: Infected animal or human. Direct or indirect contact via excretions/secretions (blood, feces, urine, saliva, milk, semen). products of animal origin: (meat, milk, skin, wool, hair) drinking water, feed, soil, environment, aerogenic , arthropods, iatrogenic infections, nosocomial (from hospital) |
| 1.Definition of infectious diseases, sources of infection, factors influencing infectious diseases (pathogen-host relationship, protection of the host, environmental factors) 2/2 | Factors influencing infectious diseases: How it is transmitted: vertical/germinative/intra uterine/galactogen/horizontal Zoonoses:orthozoonoses/cyclozoonoses/metazoonoses/sapronoses The ways of infection: natural orifices: per os, intra nasal, genital tract, udder/ conjunctiva/ per cutan, wound/ optimal entrance. source of infection: animal (carrier), environment, feed, water, etc. Forms of infection:Reinfection, exacerbation (aggravation), superinfection (after or on top of. Esp post antibiotics), secondary infection (during pre-existing or secondary to), mixed infection. Outcome of the infection (agent – host – environment) Factors affecting outcome: Agent: → relationship of the agent and the host (pathogenicity, virulence), amount of the agent, way of infection Host: → species, age, species related resistance, non spec-resistance, specific resistance, environment, nutrition, management .Agent: host-parasite relationship, normal microflora,pathogenicity (euryxen / stenoxen (width of host range stenox = wide), obligate / fac virulence (virulence factors, MLD, LD50, change of the virulence) invasiveness (intra cellular, extra cellular) amount of the agent way of infection (optimal!) Henle-Koch postulates.Host: species, age (species specific resistance)race, individual resistance (breeding lines) prod (feeding, laying)non specific resistance,skin, mucous membranes, excretions (HCl, fatty acids, bile, etc. • macrophag-phagocyte system (MPS) complement factors (properdin, opsonin) IL, IF, TNF specific resistance, passive immunity (natural, induced), active immunity (natural, induced, specific resistance humoral resistance (IgA, IgG etc.) cellular resistance (i.c. bacteria, viruses) effect of immune suppression (toxicosis, medicine, micotoxins, some agents, parturation etc.)foetal immune reaction (hierarchy, age) immune reaction of newborns (age related) : calf: Ig 4-32 days. calf, piglet: local immune reaction immediately (disappears, no immune memory). cellular immune reaction: 0-2 weeks (weaker) Environment:survival of the agent in the environment, environmental effects on animals, predisposes to facultative pathogens, nutrition, management , technology (weaning, grouping, treatment, castration, sheering, transport), physiological effects, use of an |
| 2. Pathogenesis, course, epidemiology of infectious diseases, factors influencing the spread of infectious diseases 1/3 | Infection types: 1.local infection 2.infections of different organs (localised) 3.generalised infection Pathogenesis: 1.incubation: infection → colonisation → replication 2.generalisation: spreading (blood, lymphatic vessels, perineural) → foetus (teratogenic): resorption, embryonic death, abortion 3.decreased resistance 4.tolerated infections 5.manifestation: clinical signs, lesions (virulence factors) NB: Virulence factors are molecules expressed and secreted by pathogens (bacteria, viruses, fungi and protozoa) that enable them to achieve the following:colonization of a niche in the host (this includes adhesion to cells) for example, Trimeric Autotransporter Adhesins (TAA), immunoevasion, evasion of the host's immune response, immunosuppression, inhibition of the host's immune response, entry into and exit out of cells (if the pathogen is an intracellular one), obtain nutrition from the host. Virulence factors are very often responsible for causing disease in the host because they are often responsible for converting non-pathogenic bacteria into dangerous pathogens. In bacteria, virulence factors are often encoded on mobile genetic elements, such as bacteriophages, and can easily be spread through horizontal gene transfer. |
| 2. Pathogenesis, course, epidemiology of infectious diseases, factors influencing the spread of infectious diseases 2/3 | Course: Course of infectious diseases caused by viruses: replication at the place of entry and in the regional lymph node, localisation by macrophages. replication in infected macrophages, lymphocytes, blood (viraemia). replication in lymphoid cells: immune suppression, damage of blvesls. secondary replication in tissues damage of cells: clinical signs, reactive inflammation, allergic reactions. clinical signs: Start and course of infectious diseases: Course of the disease→incubation time, course of an infection in time, peracute/acute/subacute/chronic Outcome of the disease→ recovery (full or partial), carrier, death. Infections without clinical signs: asymptomatic infections, abortive infection, inapparent (sub clinical) infection, persistent infection (virus), latent infection (virus), tolerated infection (virus), importance of infections without clinical signs. Epidemiology of infectious diseases: Characteristic of infectious diseases: infectious diseases/contagious diseases/soil infections. Statistical evaluation of infectious diseases: morbidity, mortality, lethality, incidence, prevalence. Analysing methods of infectious diseases: data collection to diagnostic work, monitoring, surveillance (passive, active), screening control of hypothesis, statistical methods, blind examinations . Extension of infectious diseases: endemic diseases (enzootia), epidemic diseases (epizootia), pandemic diseases (panzootia) Epi(widespread),endemic(localized), pandemic (virtually ww). Notification:International cooperation regarding infectious diseases: OIE (Office International des Epizooties, World Organisation for Animal Health) 1924.FAO (Food and Agricultural Organisation) 1948. WHO (World Health Organisation) 1948. |
| 2. Pathogenesis, course, epidemiology of infectious diseases, factors influencing the spread of infectious diseases 3/3 | Factors influencing the spread of epid.disease: - geographical factors (island, desert, mountain, river, soil) •climatic factors (sunshine, wind, vapour content, season) •management (overcrowding, mixing, contact, draught, NH3) •nutrition (pasture, stable, starvation) •transport (road, rail, harbour) •biological factors (mating, leave of the offspring) |
| 3. Diagnosis of infectious diseases, treatment of animals having infectious diseases 1/2 | Diagnostics of infectious diseases •complex→ epidemiological data, clinical signs, <pm lesions, all reactions, lab (diagnostic institutions), evaluation, diagnosis Diagnosing: look at: 1.epidemiology – clinical signs – pathological lesions 2.allergic tests (tuberculin, mallein) 3.laboratory diagnosis: sampling, covering letter, histological examination, microscopic examination (smear), electron microsc.ex. isolation (medium – cell culture – egg – laboratory animal), 4.serological tests: classical: agglutination, precipitation, elfo, PAGE, CFT. virus serology: VN, HAI, marked immunological methods: IF, ELISA, RIA, IRMA 4. cellular tests: a) lymphocyte stimulation test, b)immune rosette formation c) cytotoxic reaction d) macrophage migration e) g-interferon test 5.methods detecting nucleic acids (DNA hybridisation, PCR) (more diagnostic methods have to be used - complex evaluation) |
| 3. Diagnosis of infectious diseases, treatment of animals having infectious diseases 2/2 | Treatment of diseased animals aetiological treatment: bacteria: antibacterial treatment (appropriate medicine), hyperimmune serum symptomatic treatment individual / mass treatment remember: treatment of certain diseases is not allowed, some chronic diseases cannot be treated or treatment is not reasonable - prevention of complications (diseases caused by viruses) |
| 4. Prevention and control of infectious diseases 1/4 | 1.Veterinary administration general rules: all in, all out, disinfection, isolated keeping of different animal species / age groups, closed keeping, limited traffic (personal, vehicles, avoiding mixing), isolation from wild animals, rodents, birds, rendering dead animals, waste, rules of hatching, transport of day-old chicken, excluding carrier people specific rules: specific measures concerning a certain disease) |
| 4. Prevention and control of infectious diseases 2/4 | 2.immune prophylaxis: passive/active immunisation + hyperimmune serum (specially prepared) Passive: maternal immunity : - epitheliochorial: colostrum - syndesmochorial: mainly colostrum - endotheliochorial: diaplacentar + colostrum. immuno globulin content of the colostrum decreases. enteral absorption of Ig decreases. enteral lymphocytes can be transferred. bisection time, effect of the antigen on the amount of maternal antibodies, can inhibit immunisation. Colostrum (%) 1st day P+ 18.8% Ig 13.1% 3rd day: P+ 7.5% Ig 1.0% Com.milk: P+3.29% Ig 0.09% |
| 4. Prevention and control of infectious diseases 3/4 | Active immunisation factors influencing efficacy: live vaccines (attenuated) + inactivated vaccines New generation vaccines: •live vaccines: deletion vaccines, vector vaccines •not living vaccines: subunit vaccines, inactivated deletion vaccines, virus like particles (VLP) vaccines: ISCOM , synthetic vaccines, nucleic acid vaccines (DNA, ss+RNA), transgenic plant vaccine, not replicating vector vaccines , anti-idiotype vaccines - DIVA: Differentiation Infected and Vaccinated Animals |
| 4. Prevention and control of infectious diseases 4/4 | 3.chemoprophylaxis antibacterials Control, eradication - selection (test and remove) (+ vaccine), generation shift, herd replacement, SPF method, embryo transfer Examples of Eradication of human infectious diseases •smallpox (1959-1979) •polyomyelitis (some years) •rubella, mumps (target: 2010-2015) Eradication of infectious diseases of animals •Rinderpest (2011): 2010-2015) |
| 178. Principles of sampling for laboratory examinations, transport of samples 1/1 | Principles of diagnostics: Anamnesis or epidemiology: which animal species is affected, how many animals are thick, young or adults or all age groups, does the disease spread, seasonality etc. Clinical signs: fever, inappatence, depression, respiratory signs (sneezing, coughing), gastrointestinal signs (vominting , diarrhoea), reproduvtive failures (fetal demage, abortion etc.), neurologic signs (convulsions , paralysis etc.) Post mortem lesions: inflammation, necrosis, haemorrhagies Laboratory examinations: histology, detection of the antigens ( IF, captire ELISA), nucleic acids (PCR), culture (cells, embryonated eggs, serology (HI, VN, ELISA, immunoblot etc.) |
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