Module 3 Self-Assessment Review and Exam Revision Flashcards

Which of the following is TRUE for viruses?

A. They replicate using two different replication strategies
B. They range in size from 20-400µm
C. They can only be visualised using an electron microscope
D. They contain everything they need to survive
Click the card to flip 👆
1 / 15
Terms in this set (15)
Which of the following best describes a pathogen causing active viremia?

A. A viral pathogen that has been contracted indirectly via intravenous drug use
B. A viral pathogen that enters the circulation of the host by mosquito inoculation
C. A viral pathogen that replicates in epithelial cells before causing disseminated disease
D. A gastro-intestinal bacterial pathogen that enters the circulation by infecting macrophages
What are hemagglutinin and neuraminidase and why are they important for influenza vaccine development?Hemagglutinin is an antigenic glycoprotein found on the surface of influenza viruses. It is responsible for binding the virus to the cell that is being infected. Neuraminidase is an enzyme found on the surface of influenza viruses that cleaves host/viral ligand interactions (sialic acid and glycoproteins) permitting viral release. Both proteins are major immunogenic proteins that are key targets of the immune response.Define antigenic shift and antigenic drift.Antigenic drift refers to small, gradual changes that occur through point mutations in an antigen (e.g. errors caused by poor proof reading). Antigenic shift refers to an abrupt, major change in an antigen e.g., those caused by reassortment of gene segments.Michaela, a 4-month-old infant was rushed to the emergency room with acute gastroenteritis. Laboratory tests confirmed that the child was infected with a rotavirus. Answer the following questions in relation to this pathogen. A. How are rotaviral pathogens transmitted? B. Provide three public health strategies that could be implemented to control Rotavirus transmission.a) Transmission is via faecal/oral route (gastrointestinal viral pathogen). Not washing hands, direct consumption (contaminated food/water etc). b) Methods could include hand washing, washing contaminated items, appropriate disposal of faecal waste and not permitting sick children to mix with others until the infection has resolved. Vaccines are available and we vaccinate against this virus in Australia.Mark, a 28-year-old father of two diagnosed with HIV after receiving a blood transfusion while studying overseas in 1996 was prescribed several antiretroviral compounds. However, in July of 1998 he developed oral thrush and was advised that his CD4 count had dropped to 460. Answer the following questions in relation to HIV, AIDS and Mark's case in particular. A. What was the likely cause of Mark developing oral thrush and what does this condition indicate? B. How has the treatment of HIV infection changed since Mark's original diagnosis and what would have been Mark's prognosis if he was diagnosed today? C. Provide two public health strategies that may have prevented Mark's infection with HIV.a) HIV primarily targets CD4 T cells which are an important component of the immune system. As the infection progress more immune cells are destroyed. Mark's CD4 count had dropped to the point where his immune system was no longer able to protect him from opportunistic pathogens- this likely resulted in him developing oral thrush. This condition indicates that Mark's condition is deteriorating and that he is likely to progress to AIDS. b) The antiretroviral treatments available today are much more effective than they were >20 years ago. Today, while HIV infection cannot be cured it can usually be managed with chemotherapy. Indeed, studies have shown that a HIV-positive person can expect a similar life expectancy to a HIV-negative person provided they are diagnosed early and have access to treatment. c) There is no vaccine for HIV. However, education re the use of condoms, clean needles etc can aid in the prevention of transmission as can the distribution of condoms and clean needles. PREP can also be provided.Connie, a 55-year-old sex worker with a history of alcohol and drug abuse presented to her local hospital reporting jaundice and abdominal pain. Routine blood tests revealed hyperbilirubinemia and transaminitis (ALT-1316). A liver biopsy also demonstrated severe active, chronic hepatitis caused by an infectious agent. Answer the following questions in relation to this case. A. What infectious pathogen is the likely cause of Connie's infection and why B. How should Connie's infection be treated? C. Discuss and provide at least two reasons why this pathogen remains a cause of disease around the worlda) HCV -most common cause of chronic viral hepatitis in adults b) Antivirals (ribavirin) - Interferon-alpha c) Answers could include - (1) no available vaccine, (2) quasi species facilitates pathogen survival and chronic infections so many people may not be aware of their infections - facilitates transmission (3) limited chemotherapeutic treatments and access to chemotherapies (global incidence even in low socio-economic regions). But remember to read the questionyou are asked to discuss, not list.