EPIDEMIOLOGY, INFECTIOUS DISEASES

1. EPIDEMIOLOGY, INFECTIOUS DISEASES

2. Department of Microbiology and Infectious Diseases Budapest, XIV. Hungária krt. 23-25. Telephone: 251.9900 Internal phone: 8090, 8091 Fax: 251.9260 E-mail: Fodor.Laszlo@aotk.szie.hu

3. Department of Microbiology and Infectious Diseases • Lectures • Bakonyi, Tamás: Associate Professor • Fodor, László: Professor • Makrai, László: Associate Professor • Tuboly, Tamás: Professor • Varga, János: Professor • invited speakers

4. Department of Microbiology and Infectious Diseases • Plenary practicals • Bakonyi, Tamás: Associate Professor • Fodor, László: Professor • Hornyák, Ákos: Head of Department • Makrai, László: Associate Professor • Tuboly, Tamás: Professor • Varga, János: Professor • Diagnostical practical • 4 weeks

5. Importance of infectious diseases • all areas of veterinary medicine • great economic impact (avian influenza 20 bn $) • trade of animal and animal products • zoonoses • food hygiene, food safety • 25% of human death cases is because of infective agents

6. Subject of „Epidemiology, infectious diseases” • Structure • lectures • plenary practicals (from 10th October, 2011) • practice at diagnostic institute • midterm exam (24th October, 21st November) • Content • general epidemiology • diseases caused by viruses • diseases caused by prions • diseases caused by bacteria

7. Literature • Hagan and Brunner’s Microbiology and Infectious Diseases. 8th Ed. Comstock Publishing Associates 1988. • Kahn (Ed.): The Merck Veterinary Manual. 10th Ed. Merck & Co. 2010. www.merckvetmanual.com • http://www.oie.int • Straw, B. et al. (Eds.): Diseases of swine. 9th Ed. Blackwell. 2006. • Saif, Y.M. (Ed.Ch.): Diseases of poultry. 12th Ed. Blackwell. 2008. • Radostits, O.M. (Ed.): Veterinary Medicine 10th Ed. Elsevir. 2007.

8. HISTORY OF INFECTIOUS DISEASES • Varro (2nd cent B.C.): living agents • Fracastoro (16th cent.) „contagium vivum” • Leeuvenhoek (17th-18th cent.): microscope • Pollender (19th cent.): bacteria in the blood of animals with anthrax • Pasteur-Koch (19th-20th cent.) • Ivanovsky (19th cent.): virus • Löffler and Frosch (1897): foot and mouth disease virus • Jenner (1796): pox • Mechnikov (1884): phagocytosis • Behring (1890): antibodies in the blood • eradication of infectious diseases

9. Infectious disease • agent (lower ranked) • host (higher ranked) • exposition - disposition • phases of infection

10. Sources of infection • source: generally infected animals / humans • direct • indirect • excretions, secretions (blood, faeces, urine, saliva, milk, semen,) • products of animal origin (meat, milk, skin, wool, hair) • drinking water, feed • soil, environment • aerogenic • arthropods • iatrogenic infections • nosocomial

11. Transmission of diseases • vertical • germinative • intra uterine • galactogen • horizontal • Zoonoses • orthozoonoses • cyclozoonoses • metazoonoses • sapronoses

12. Infection • ways of infection • 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 • superinfection • secondary infection • mixed infection

13. Outcome of the infection (agent – host – environment) • agent • relationship of the agent and the host (pathogenicity, virulence) • amount of the agent • way of infection • host • species, age • species related resistance • non specific resistance • specific resistance • environment • nutrition • management

14. Outcome of the infection (agent – host - environment) • Agent • host-parasite relationship • normal microflora • pathogenicity (euryxen / stenoxen, obligate / facultative pathogen) • 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

15. Outcome of the infection (agent – host – environment) • Host • species, age (species specific resistance) • race, individual resistance (lines) • production (feeding, laying) • non specific resistance • skin, mucous membranes, excretions (HCl, fatty acids, bile, etc. • macrophag-phagocyte system (MPS) • complement, properdin, opsonin • IL, IF, TNF • specific resistance • passive immunity (natural, induced) • active immunity (natural, induced)

16. 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

17. Outcome of the infection (agent – host – environment) • Environment • survival in the environment • environmental effects on animals • predisposes to facultative pathogens • nutrition • management • technology (weaning, grouping, treatment, castration, sheering, transport) • physiological effects, use of animals

18. Course of an infectious disease • local infection • infections of different organs (localised) • generalised infections • incubation: infection, colonisation, replication • generalisation: spreading (blood, lymphatic vessels, perineural) • foetus: • resorption, embryonic death, abortion • teratogenic • decreased resistance • tolerated infections • manifestation: clinical signs, lesions (virulence factors)

19. 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 blood vessels • secondary replication in tissues • damage of cells: clinical signs • reactive inflammation, allergic reactions • clinical signs

20. 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

21. Infections without clinical signs • forms of infections without clinical signs • abortive infection • inapparent (sub clinical) infection • persistent infection (virus) • latent infection (virus) • tolerated infection (virus) • importance of infections without clinical signs

22. Epidemiology of infectious diseases • Characteristic of infectious diseases • infectious diseases • contagious diseases • soil infections • Statistical evaluation of infectious diseases • morbidity • mortality • lethality • incidence • prevalence

23. Analysing methods of infectious diseases • data collection to diagnostic work • monitoring • surveillance (passive, active) • screening • control of hypothesis • statistical methods • blind examinations

24. Extension of infectious diseases • endemic diseases (enzootia) • epidemic diseases (epizootia) • pandemic diseases (panzootia) • 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.

25. Factors influencing infections • 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)

26. Diagnostics of infectious diseases • complex • epidemiological data • clinical signs • pathological lesions • allergic examination • laboratory examinations (diagnostic institutions) • evaluation, diagnosis

27. Diagnostics of infectious diseases • epidemiology – clinical signs – pathological lesions • allergic tests (tuberculin, mallein) • laboratory diagnosis • sampling, letter • histological examination • microscopic examination (smear) • electron microscopic examination • isolation (medium – cell culture – egg – laboratory animal) • serological tests • classical: agglutination, precipitation, elfo, PAGE, CFT • virus serology: VN, HAI • marked immunological methods: IF, ELISA, RIA, IRMA

28. Diagnostics of infectious diseases • cellular tests • lymphocyte stimulation test • immune rosette formation • cytotoxic reaction • macrophage migration • g-interferon test • methods detecting nucleic acids (DNA hybridisation, PCR) • more diagnostic methods have to be used • complex evaluation

29. Treatment of diseased animals • aetiological treatment • symptomatic treatment • bacteria: antibacterial treatment (appropriate medicine) • individual / mass treatment • 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) • hyperimmune serum

30. Prevention and control of infectious diseases • veterinary administration, rules • general rules • specific measures • immune prophylaxis • chemoprophylaxis

31. Prevention and control of infectious diseases • rules, veterinary administration • international transport, certificates • import restrictions • quality requirements • localisation

32. Prevention and control of infectious diseases • 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

33. Prevention and control of infectious diseases • veterinary administration • general rules • specific rules • specific measures concerning a certain disease • immuneprophylaxis • passive immunisation • active immunisation • chemoprophylaxis

34. Immune prophylaxis • Passive immunisation • hyperimmune serum • maternal immunity • epitheliochorial: colostrum • syndesmochorial: mainly colostrum • endotheliochorial: diaplacentar + colostrum • immuno globulin content of the colostrum is decreasing Colostrum (%)

35. enteral absorption of Ig is decreasing • enteral lymphocytes can be transferred • bisection time • effect of the antigen on the amount of maternal antibodies • can inhibit immunisation

36. Immunprophylaxis • Active immunisation • factors influencing efficacy • live vaccines (attenuated) • inactivated vaccines

37. New generation vaccines • live vaccines • deletion vaccines • vector vaccines • not living vaccines • subunit vaccines • inactivated deletion vaccines • ISCOM vaccines, virus like particles • synthetic vaccines • nucleic acid vaccines (DNA, ss+RNA) • transgenic plant vaccines • not replicating vector vaccines • anti-idiotype vaccines • DIVA: Differentiation Infected and Vaccinated Animals

38. Prevention and control of infectious diseases • veterinary administration • general rules • specific rules • specific measures concerning a certain disease • immuneprophylaxis • passive immunisation • active immunisation • Chemoprophylaxis • antibacterials

39. Control, eradication • selection (test and remove) (+ vaccine) • generation shift • herd replacement • SPF method • embryo transfer • 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)