L1 - Introduction to Agents of Disease

Structure of AVBS 3001

  • Modules Included:

    • Bacteriology and Mycology: Study of bacteria and fungi.

    • Virology: Focus on viruses and prions.

    • Parasitology: Analysis of metazoan parasites (worms and arthropods) and protozoa.

  • Course Format: Comprises 9-13 lectures coupled with 3 practical/tutorial sessions.

Course Facilitators

  • Instructors:

    • Gary Muscatello

    • Tim Newsome

    • Emily Francis

    • Jan Slapeta

    • Carola Venturini

    • Katharine Muscat

    • Roisin Sullivan

    • Alana Kidd

Unit Goals

  • Aim to learn about important infectious disease-causing agents in animals.

  • Identification and classification of these pathogens, along with diagnostic methods.

  • Recognize pathogenic traits and the diseases affecting different animal hosts.

  • Grasp the host-pathogen-environment relationship and apply this understanding to control and prevent diseases.

Focus Areas for the Course

  • Concentration on production animals and wildlife.

  • The course complements Animal Health and Disease (AVBS3005) and prepares students for future studies in LDI (AVBS3888) and ONE Health (AVBS40202) as well as honors projects.

Assessments Overview

  • Literature Review:

    • Analyze a recent scientific paper on a specific viral pathogen affecting animals.

    • Choose two additional papers to develop a cohesive theme – must be from 2021-2026 excluding review articles.

    • 1500-word review is required, focusing on the agent and insights from the literature, due March 24.

    • One-page draft highlighting findings and exploration plans is also needed.

    • Worth 25% of the overall grade with a feedback deadline of April 22 (Week 8).

  • Mid-Semester Quiz:

    • An open book quiz covering materials from weeks 1 to 8; lasting 60 minutes for 30 marks (MCQs and SAQs), worth 10% of the total grade, scheduled for Week 9 with a revision tutorial on the Monday following.

  • Group Case Report:

    • Groups (up to 5 students) work collaboratively on an infectious disease scenario pertaining to a specific animal or industry.

    • 1000-word report detailing investigation plans and original flow diagrams is required, due May 13 (Week 11), worth 15% of total grade.

  • Written Examination:

    • Conducted over 2 hours, comprising 30 MCQs, 4 short answer questions (10 marks each), and 2 short essay/case-based questions (15 marks each).

    • Closed book format and must cover all material with a hurdle requirement of 40%. Examinable topics include both practical and tutorial materials.

Generative AI Usage in Assessments

  • Allowed Uses:

    • AI can assist with non-summative tasks such as grammar checking and structuring for the literature review.

    • Must declare AI use in submissions; direct quotations or summaries from AI are considered academic dishonesty.

    • In group assignments, AI can help with the report's structure and flow diagram generation.

  • Prohibitions:

    • Do not use AI for generating reports or conducting analyses for tasks; such actions are considered dishonesty.

    • The use of DeepSeek for any assessments is not permitted.

Attendance Requirements

  • Practical and Tutorial Classes:

    • Attendance is mandatory for 2 out of 3 of the practical sessions conducted on campus across various weeks allowing for different subjects.

    • Failure to meet attendance can result in an Absent Fail grade. Lectures will be available in recorded format and on CANVAS following the scheduled timetable.

Practical Laboratory Instructions

  • Location:

    • Bacteriology in PC2 labs; critical adherence to safety protocols is necessary.

    • Parasitology in designated labs with required safety gear: lab coat and safety glasses.

Recommended Textbooks and Resources

  • Core Textbooks:

    • "Australasian Animal Parasites Inside & Out", Saunders, 5th Edition

    • "Veterinary Microbiology and Microbial Disease", Blackwell Publishing, 2nd Edition

    • "Pathogenesis of Bacterial Infections in Animals", Wiley-Blackwell

Understanding Disease

  • Definition of Disease:

    • Disease describes a change in the host's health status impeding normal functions due to the influence of one or more agents.

  • Classification of Disease:

    • Clinical Disease: Observable changes indicating dysfunction.

    • Subclinical Disease: Indiscernible by symptoms but detectable through laboratory tests, affecting productivity.

Disease Causation and Agents

  • Agents of Disease:

    • Categories:

    • Physical agents

    • Genetic/inherited factors

    • Chemical agents

    • Infectious agents: These invade and multiply in hosts, producing harmful chemicals or toxins.

  • Significant Characteristics of Infectious Agents:

    • Can be directly or indirectly transmissible and are crucial to understanding disease dynamics.

Strategies for Protecting Animals

  • Essential Knowledge:

    • Understanding interactions between infectious agents, hosts, and the environment to pioneer effective strategies for disease prevention and control.

  • Protective Measures:

    • Factors like breeding, age, vaccination, nutrition, and biosecurity play crucial roles.

Pathogenesis of Infectious Diseases

  • Understanding Pathogenesis:

    • The interactions between host, pathogen, and environment are pivotal in shaping disease processes.

    • Important to identify virulence factors and predict disease outcomes for better management.

Infection vs. Disease

  • Definitions:

    • Infection: Presence and multiplication of an infectious agent in/on an animal without necessarily causing disease.

    • Carrier: An organism that harbors the infectious agent without showing symptoms yet capable of spreading the agent.

Host-Infectious Agent Relationships

  • Parasitism:

    • Harmful relationship where organisms benefit at the expense of the host.

    • Study of parasitology encompasses metazoans and protozoans alongside microbial parasites such as bacteria, fungi, and viruses.

  • Other Relationships:

    • Mutualism: Beneficial interactions for both host and organism, e.g., gut bacteria in ruminants.

    • Commensalism: Relationships that do not harm the host, often involving normal flora.

    • Both mutualistic and commensal relationships can transition to parasitism under changing conditions.

Consequences of Animal Infectious Diseases

  • Impact on Animal Health:

    • Affects productivity and diversity impacting farming and food security.

    • May lead to ecological imbalances and public health repercussions.

Zoonotic Diseases

  • Definition of Zoonoses:

    • Diseases transmitted between animals and humans. Approximately 75% of emerging human infectious diseases are zoonotic, including significant conditions such as anthrax and COVID-19.

Causation in Infectious Disease

  • Understanding Conditions:

    • Infectious diseases arise from an interaction favoring pathogens leading to disease.

    • Factors influencing disease risk include parasitic, host, and environmental factors.

Factors Influencing Disease Risk

  • Parasitic Influences:

    • Variability in strains and their virulence, with higher virulence correlating to a greater likelihood of disease manifestation.

  • Host Factors:

    • Species, age, nutrition, and immune competence are crucial predictors of susceptibility to infectious diseases.

  • Environmental Influences:

    • Weather conditions, population density, and availability of resources significantly influence disease outcomes.

Establishing Causation

  • Evidence Gathering:

    • For individuals, establish solid links between pathogens and observed disease processes through evidence demonstrating significant concentration and virulence traits.

  • Population Evidence:

    • Establish epidemiological associations following Koch’s postulates, focusing on strength, temporality, and dose-dependency.

Holistic Approach in Disease Control

  • Issues Beyond the Pathogen:

    • Disease control may be achieved more effectively via modifications to the environment and host factors rather than merely identifying pathogens.

    • Comprehensive understanding of host and environmental factors is essential for effective disease management in animal populations.

Role of Graduates in Animal Health

  • Future Responsibilities:

    • Engage in surveillance and outbreak investigations, laboratory testing, research for vaccine development, policy advice, and educational outreach.