(3.) Infectious Diseases and Epidemiology - Key Concepts (Lecture Notes)

A set of Q&A flashcards covering epidemiology terms, key pathogens, transmission modes, vaccine principles, and emergence/response concepts from the lecture notes.

What is a pandemic?

An infectious disease outbreak that spreads across countries or worldwide, not confined to a single region.

What is an epidemic?

A rapid increase in disease cases within a specific region or population.

What is an endemic?

A disease that is constantly present in a population or area at baseline levels.

What does sporadic mean in epidemiology?

Random, isolated disease cases scattered in time/place with no sustained transmission.

What is the causative organism and type of plague?

Yersinia pestis, a bacterium transmitted by fleas from rodents.

How is plague transmitted to humans?

Bites of fleas that feed on infected rodents; respiratory transmission can occur if the infection reaches the lungs.

What are key features of measles?

Caused by measles virus; symptoms include high fever, cough, coryza, conjunctivitis, Koplik spots; virus can survive on surfaces up to 2 hours.

What is the measles vaccination schedule?

First dose at 12–15 months; second dose before entering school.

What is influenza and which type causes epidemics and pandemics?

Influenza viruses types A, B, C; Type A causes epidemics and pandemics and has multiple animal hosts.

What is antigenic shift and its significance?

Major changes in viral surface antigens due to gene reassortment; associated with epidemics and pandemics.

What is antigen in immunology?

A substance that triggers an immune response resulting in antibody production.

What are the general vaccine evolution stages described?

From whole-cell vaccines to subunit (acellular) vaccines to toxoid vaccines to DNA/RNA vaccines; mRNA vaccines are now common.

What is the influenza vaccine composition (trivalent)?

A trivalent vaccine: two influenza A strains (H1N1 and H5N1) and one influenza B strain.

How is organism naming formatted in binomial nomenclature?

Genus name capitalized; species name lowercase; both italicized; genus comes first.

What is Borrelia burgdorferi and how is Lyme disease transmitted?

The bacterial cause of Lyme disease; transmitted by tick bites (Ixodes); early symptoms include flu-like symptoms and sometimes a bull’s-eye rash; can affect joints, heart, and nervous system.

How can Lyme disease be prevented?

Avoid tick bites by wearing long sleeves, tucked-in pants, light-colored clothing, performing tick checks, using DEET or natural repellents.

What is MRSA?

Methicillin-resistant Staphylococcus aureus; a common hospital-acquired infection that can range from pimples to abscesses to sepsis; prevent with strict hygiene and isolation when needed.

What is Cryptosporidium parvum and cryptosporidiosis?

A protozoan parasite causing cryptosporidiosis; transmitted by ingestion of contaminated water; causes diarrhea by damaging intestinal crypts; dangerous for immunocompromised.

What are major factors driving emergence and reemergence of infectious diseases?

Ecological changes, international travel, global commerce, technology, microbial adaptation (mutations), and breakdowns in public health infrastructure.

What is the role of surveillance and response in emerging diseases (1995 goals)?

Four goals: surveillance, trained personnel, research funding, and prevention/control; coordinated by agencies like CDC and WHO.

What is the transmission cycle of West Nile virus?

Mosquitoes transmit the virus, cycling between birds and mosquitoes; humans are incidental hosts.