PPEM 454 Virus Ecology Course Syllabus

The PPEM 454 Virus Ecology course syllabus is subject to change. Updates will be posted on ANGEL/CANVAS.


Instructor: Dr. Marilyn J. Roossinck, Professor
Class Location: 201 Buckhout Lab
Class Schedule: Tues/Thurs | 9:45–11:00 a.m.


This course will provide a perspective about virology that is different from the paradigm of viruses only as agents of disease. All living entities are hosts for viruses; the presence of viruses can be detrimental, neutral, or beneficial, depending on the ecological context. Students will gain a basic understanding of the ecology of viruses: how viruses interact with their hosts and how those interactions modulate the hosts' interactions with their environment.


By the conclusion of the course students will:

  1. Appreciate the role viruses play in the biosphere;
  2. Understand how viruses interact with their hosts in the context of host ecology and evolution;
  3. Be able to critically assess scientific literature.


Textbook: The OPTIONAL textbook for this course is Studies in Viral Ecology, Volumes 1 and 2, 2011, edited by Christon J. Hurst. Two copies of these books are available on reserve for this course in the Albert C. Hildebrandt Plant Pathology Library. Supplemental reading will be assigned with some lectures. These will be posted on the class ANGEL/CANVAS site.


The students will participate in an interactive lecture series, a virus ecology class project, class quizzes with discussion, and interpretation of scientific literature


The students will participate in an interactive lecture series, a virus ecology class project, class quizzes with discussion, and interpretation of scientific literature.

Participation 90
Quizzes 50
Presentation 100
Midterm exam 100
Project 60
Final exam 100

Grades will be assessed on class participation, work on the class project, quiz scores, a midterm exam, a paper presentation, and a final exam.

GradePoints Earned
A 451–500
B 401–450
C 351–400
D 301–350


Electronics: You may use a laptop or electronic notebook for taking notes. Please keep your cell phone turned OFF and do not text, read email, or surf the web during the class. These activities will reduce your class participation points for the day.

The class begins at 9:45 a.m. It does not begin at 9:50 or 10:00. Please be courteous to your professor and your fellow classmates and come on time. Tardiness will result in a deduction of your participation points.

Makeup exams and quizzes will be offered to students who have a legitimate excuse according to university attendance policies and must be arranged with the instructor. You must notify the professor by email, no later than 9:00 a.m. the day of the class if you have an illness/emergency that prevents you from attending any class.

Right and wrong answers: For all exams and quizzes, please answer to the best of your knowledge, but do not guess. Questions left blank will receive zero points, but questions answered wrong may receive negative points.



8/23 Introductions and prior knowledge Prior knowledge assessment
8/25 1 Basics of virology and ecology 1.1 Basics of Virology I Discussions
1.2 Basics of Virology II
8/30 1.3 Basics of Ecology I Intro to class project
9/1 1.4 Basics of Evolution I
9/6 2 Viruses and symbiosis 2.1 Viruses as Symbionts Discussion
9/8 2.2 Mutualistic Viruses Paper discussion
9/13 3 Virus biodiversity 3.1 Viruses in the Sea - Phage Studies Tips on reading scientific papers
9/15 3.2 Plant Virus Biodiversity Discussion
9/20 3.3 Viruses in Other Eukaryotes Paper discussion
9/22 3.4 Phage and Phage Ecology
9/27 3.5 Giant Viruses
9/29 4 Complex interactions 4.1 Adaptation to Extreme Environments
10/4 Field trip - Environmental viruses
10/6 4.2 Plants, Viruses, and Insects Discussion of field trip results
10/11 5 Host species invasion 5.1 Killer Viruses
10/13 5.2 Viruses as Bioweapons
10/18 6 Population control 6.1 Viruses as Regulators of Host Populations
10/25 7 Host ecology changes 7.1 Human Viral Diseases and Changes in Human Lifestyles
10/27 7.2 Viruses Affecting Other Disease States
11/1 8 Fitness effects 8.1 Influenza
11/3 8.2 Emerging Viruses
11/8 9 Zoonotic viruses 9.1 Measuring Fitness Guest lecturer Edelio Bazán
11/10 9.2 Rapid Adaptation
11/15 10 Viruses changing hosts 10.1 Symbiogenesis
11/18 10.2 Viruses and Host Evolution
11/29 11 Virus-like entities 11.1 Viroids, Prions, and Satellites Discussion
12/6 Project presentations
12/8 Project presentations

Academic Integrity

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Academic integrity is the pursuit of scholarly activity in an open, honest, and responsible manner. Academic integrity is a basic guiding principle for all academic activity at The Pennsylvania State University, and all members of the university community are expected to act in accordance with this principle. Consistent with this expectation, students should act with personal integrity; respect other students' dignity, rights, and property; and help create and maintain an environment in which all can succeed through the fruits of their efforts. Academic integrity includes a commitment not to engage in or tolerate acts of falsification, plagiarism, misrepresentation, or deception. Such acts of dishonesty violate the fundamental ethical principles of the university community and compromise the worth of work completed by others (see Faculty Senate Policy 49‐20 and G‐9 Procedures).

Academic Integrity Guidelines for the College of Agricultural Sciences

Disability Statement

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In order to receive consideration for reasonable accommodations, you must contact the appropriate disability services office at the campus where you are officially enrolled, participate in an intake interview, and provide documentation. If the documentation supports your request for reasonable accommodations, your campus’s disability services office will provide you with an accommodation letter. Please share this letter with your instructors and discuss the accommodations with them as early in your courses as possible. You must follow this process for every semester that you request accommodations.

Contact Information

Marilyn J. Roossinck, Ph.D.
  • Professor, Plant Pathology and Environmental Microbiology, and Biology
Phone: 814-865-2292