Learning objectives
The course aims to enable the student to know and understand elements of etiology and epidemiology, the latter useful to contextualize the diseases in population medicine.
Course unit content
The course consists of two modules, which combine to provide elements for the future understanding of infectious diseases.
Epidemiology: study of the methods applied to the understanding of the epidemiology of diseases of veterinary interest.
Microbiology and Immunology: basic notions related to bacteriology, mycology, virology and immunology.
Full programme
1. Introduction to the study of epidemiology. Historical considerations and basic concepts. Differences between epidemiology and other diagnostic disciplines. The concept of disease determinant. Primary determinants. Secondary determinants. The concept of "population". Levels of populations.
2. Tasks and aims of epidemiology. Tasks of veterinary epidemiology. Prevention, control and eradication of diseases. The aims of epidemiological studies. Observational and experimental studies.
3. From association to causality. Demonstration of causality in observational studies. Statistical significance and causality. Chi-square test for comparing two percentages. Statistical significance tests. Association and causality: types of association. General model of causal and non-causal associations. Examples of causal and non-causal associations.
4. The epidemiological approach to the causes of disease. Henle-Koch's postulates. Evans's postulates. The Rules of John Stuart Mill. Demonstration of causality. Criteria of causality. Prospective and retrospective studies for demonstrating causality. Prevalence rate, relative risk and odds ratio.
5. Biological variability: basic concepts in epidemiology. Frequency distribution. Cumulative, median and centile frequencies. Central tendency indices. Variation indices.
6. Sampling in veterinary practice. Aims of sampling. Characteristics of a good sample. Sampling errors. Sampling methods. The variability of an estimate and confidence limits. Sample size.
7. Measuring disease frequency. General concepts. Morbidity and mortality. Survival and lethality. Prevalence and incidence. Attack rate. Relationship between incidence and prevalence. Epidemic, endemic and sporadic diseases. Other methods for measuring disease frequency. Standardisation of measures.
8. Screening tests for sub-clinical diseases. Population screening. Test performance assessment. Sensitivity, specificity, positive and negative predictive value. Methods for improving the predictive value of a test. Multiple tests: use of 2 tests simultaneously or in succession; serial or parallel interpretation. Concordance index between two tests.
9. Transmission and maintenance of infectious diseases Transmissible diseases. The cycle of a transmissible disease. Latent infection and carrier status. Horizontal and vertical, direct and indirect transmission. Host types. Mechanical and biological vectors. Factors associated with the spread of infections. The spread of infections and host characteristics: receptiveness and contagiousness. The spread of infections and agent characteristics. The spread of infections and contact efficiency. Routes of infection. Transmission modes. Long distance transmission of disease agents. Vertical transmission of disease. Maintenance and survival strategies of the agent.
10. Disease patterns. Epidemic curves. Kendall’s threshold theorem. Epidemic trends. Common source and propagation epidemics.
11. Models in epidemiology. Model types and functions. A classic model: the Reed & Frost model. Bovine Neospora caninum Infection: example of a mathematical model.
PRACTICAL LEARNING ACTIVITIES. With the aid of the computer and preparation of spreadsheets, students will consolidate the concepts acquired by solving problems relative to: demonstration of cause-effect relationship (case-control and cohort studies), sampling, measuring disease frequency, critical interpretation of screening tests.
According to guidelines of the European Association of Establishment for Veterinary Education, students will learn principles on finding technical-scientific informations via Internet using public online databases (OPAC SBN, PUBMED etc.).
Bacteriology
Shape, dimensions, spatial arrangement. Structure of the cell
prokaryotic: nucleus, cytoplasm, cytoplasmic inclusions, ribosomes,
plasmids, cytoplasmic membrane, mesosome, bacterial cell wall, flagella,
organs of adhesion capsule antigens. Protoplasts, spheroplasts, forms L. The
Spore: sporogenesis, the structure of the spore, germination, biological meaning.
Nutrition, metabolism and bacterial cultivation strategies defined on the
the basis of different intrinsic needs. Reproduction: the growth curve.
Criteria for bacterial identification and taxonomy.
Bacterial genetics: mutations, recombinations (transformation,
conjugation and transduction), converting phage, plasmids and R one, islands
pathogenicity. Biotechnology: Concepts and basic techniques of engineering
genetics. Concept of pathogenicity: virulence, infectivity, receptivity,
infection, disease, concept of healthy carrier; pathogenicity factors.
Molecular techniques applied to microbiological diagnostics. Genesis and
evolution of an infectious disease: primary lesion, dissemination,
tropisms.
Understanding the disinfection. Antibiotics: classes and mechanism
of action.
MYCOLOGY
General characteristics of fungus. Pathogenic action of fungus and main
pathogens of interest in veterinary medicine. Immune response to
fungal infections. Strategy to fight fungal infection.
Virology
Chemical composition, size, structure of the virus symmetry cubicaelicoidale,
complex, capsid, capsomeres, peplos, peplomers.
Bacteriophages. Interaction of viruses with eukaryotic cells:
adsorption, penetration, replication, maturation, liberation.
Cultivation: tissue culture, cell culture, animal receptive, eggs
embryos.
T itolazionedeivirus: metodifisici, biologiciemediante
hemagglutination.
Taxonomic Characteristics of DNA viruses and RNA. Infectious agents
unconventional.
IMMUNOLGY
Nonspecific mechanisms of protection of the skin and mucous membranes. Phagocytosis:
phagocytes professionals and occasional osponine, the dynamics of phagocytosis,
fate of phagocytosed microorganisms, the consequences of survival.
Antigens: digit value physico-chemical determinants or epitopes, haptens and carriers,
immunogenicity, antigen-dipedenti thymus-independent and thymus.
Humoral immunity: primary and secondary lymphoid organs, classes of lymphocytes,
production of antibodies, structures and classes of immunoglobulins,
distribution.
Local immunity and cell-mediated. Primary and secondary response,
memory, recirculation of lymphocytes. Active immunity: infection,
vaccination, vaccine types, routes of administration. Immunity
passive transplacental, colostrum, from-immune sera. Complement:
components, via classical, alternative and properdinica activation,
functions.
Interferons: classes, production, biological significance in antiviral defense
and in the immune response delayed. Hypersensitivity. Reactions
Serologic: precipitation, agglutination, hemagglutination and its
inhibition, neutralization, fissazionedelcompleme nto,
immunofluorescence, tecnicheradioimmunolo gichee
immunoassays.
PRACTICAL TEACHING
Bacterial cell wall and the Gram stain. Architecture of the spore and
staining Shaeffer and Fulton. Structure of the capsule and color
by ink. Various biochemical and enzymatic tests (oxidase,
catalase, urease, TSI, lysine and ornithine decarboxylase, esculinasi, reduction
nitrates, chemical Gram). Rapid slide agglutination and latex.
Identification system API. Various techniques of sowing of liquid medium and
solid. Susceptibility and MIC. Structure and coloration of Saccharomyces
cerivisiae. Microscopic examination of Malassezia. Cultivation of
virus in cell culture and embryonated eggs. Evaluation of different effects
cytopathic. Titration of virus using hemagglutination and method
lysis plaques.
Bibliography
BOTTARELLI E.: Quaderno di Epidemiologia Veterinaria. http://www.quadernodiepidemiologia.it.
TESTI DI CONSULTAZIONE
AHLBOM A., NORELL S.: Epidemiologia moderna. Il Pensiero Scientifico Editore, Roma, 1993
BEAGLEHOLE R., BONITA R., KJELLSTROM: Epidemiologia di base. Edizione italiana a cura di G. Agazzotti, Editoriale Fernando Folini, Casalnoceto, 1997.
LOPALCO P.L., TOZZI A.E. (2003) Epidemiologia facile. Il Pensiero Scientifico Editore, Roma.
PFEIFFER D.U., Veterinary Epidemiology - An Introduction. Institute of Veterinary, Animal and Biomedical Sciences, Massey University, New Zealand. Disponibile online (al 25/9/2009) all'indirizzo: http://www2.vetmed.wisc.edu/education/courses/epi/Pfeiffer.pdf
Signorelli C. (2000) Elementi di metodologia epidemiologica. Società Editrice Universo, Roma, V ed.
Abbas A.K. et alt. Immunologia cellulare e molecolare. Elsevier 2010
Poli at elt. Microbiologia e immunologia veterinaria. UTET 2009.
Brock Biologia dei microrganismi (volumi 1, 2, 3)Pearson 2012.
Teaching methods
Frontal lessons, practical activity in laboratory and informatic room.
Assessment methods and criteria
The exam consists of two steps: written examination for Epidemiology and oral examination for Microbiology and immunology. The final mark is derived from the arithmetic mean of the marks obtained in the two modules.
