Infectious Diseases: Types, Vaccines, and Public Health

What are infectious diseases caused by?

Pathogens, which are microbes that can lead to illness.

What percentage of all microbes are classified as pathogens?

Less than 1%.

Name four types of pathogens that cause infectious diseases.

Bacteria, viruses, fungi, and parasites.

What are some examples of infectious diseases?

Tuberculosis, HIV, malaria, and COVID-19.

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What disease was eradicated due to vaccination in 1980?

Smallpox.

Which diseases have seen significant declines in the US due to vaccination?

Tetanus, diphtheria, mumps, measles, rubella, and pertussis.

What is the significance of the MMR vaccine?

It has been crucial in preventing measles outbreaks.

What are some diseases that currently lack effective vaccines?

Common cold, strep throat, HIV, chlamydia, and Lyme disease.

What challenges do diseases without vaccines pose to public health?

They can lead to widespread outbreaks.

What is an epidemic?

An unexpected increase in disease cases within a specific geographical area.

What defines a pandemic?

A disease that spreads exponentially across multiple countries and continents.

What historical pandemics had profound impacts on society?

The Black Death and the 1918 influenza pandemic.

What is the role of antibiotics and antiviral medications in managing infections?

They are significant in managing infections where vaccines are not available.

Why is ongoing research into vaccine development important?

To create vaccines for diseases that currently lack effective immunization.

What is the importance of public awareness and education about infectious diseases?

It can help reduce transmission and improve health outcomes.

What is zoonosis?

Infectious diseases that can be transmitted between animals and humans.

What percentage of human infectious diseases originate from zoonotic pathogens?

Approximately 60-75%.

What factors are linked to the emergence of zoonotic diseases?

Environmental changes, habitat destruction, and increased human-wildlife interactions.

How is the COVID-19 pandemic related to zoonotic diseases?

It is believed to have originated from zoonotic transmission.

What characterizes hot spots for zoonotic diseases?

High human populations and frequent contact with wildlife.

What virus causes smallpox?

The variola virus.

Who developed the first smallpox vaccine and when?

Edward Jenner in 1796.

What was the basis for Jenner's smallpox vaccine?

Observing that dairymaids infected with cowpox were immune to smallpox.

What does the term 'vaccination' derive from?

The Latin word 'vacca', meaning cow.

What ethical considerations arose from Jenner's vaccination method?

Questions about consent and medical experimentation on children.

What contributed to the successful eradication of smallpox?

Global vaccination efforts, public health initiatives, and certification logos for eradication.

What did Ignaz Semmelweis advocate for to reduce disease transmission?

Handwashing among physicians.

What is the 'Semmelweis reflex'?

The tendency to reject new ideas that contradict established beliefs.

What theory did Louis Pasteur establish?

The germ theory of disease.

What process did Louis Pasteur develop to improve food safety?

Pasteurization.

What are Koch's postulates?

Criteria to establish a causative relationship between a microbe and a disease.

What is the causative agent of typhoid fever?

Salmonella enterica serotype Typhi.

How is typhoid fever transmitted?

Through the fecal-oral route, primarily via contaminated food or water.

Who was Typhoid Mary?

Mary Mallon, the first identified healthy carrier of typhoid fever, who unknowingly spread the disease while cooking for families.

What action was taken against Typhoid Mary in 1907?

She was forcibly quarantined for public health safety.

What is the mortality rate of untreated typhoid fever?

About 30%.

What are the two main methods of preventing typhoid fever?

Vaccination and antibiotics.

What does the cell theory state?

All living things are composed of one or more cells, which are the basic structural units of life.

What is the key difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus and organelles, while eukaryotic cells contain a nucleus and organelles.

What is taxonomy?

The science of classifying organisms using a hierarchical structure based on shared characteristics.

Under which domain and kingdom are humans classified?

Domain Eukarya and kingdom Animalia.

What percentage of measles cases in recent outbreaks were unvaccinated or had unknown vaccine status?

92%.

What are the complications associated with measles?

Pneumonia, hospitalization, measles amnesia, and acute encephalitis.

What is herd immunity, and what percentage is required for measles?

Herd immunity requires approximately 94-95% vaccination coverage.

What was the status of measles in the U.S. before recent outbreaks?

Measles was declared eliminated in the U.S. in 2000.

What is measles amnesia?

The loss of immune memory that can increase susceptibility to other infections post-recovery.

What factors are contributing to the resurgence of measles?

Declining vaccination rates, misinformation, and vaccine hesitancy.

What is the significance of the MMR vaccine in relation to measles outbreaks?

Declining vaccination rates for the MMR vaccine are a primary driver of recent outbreaks.

What is the relationship between vaccination rates and measles outbreaks?

Low vaccination rates lead to increased susceptibility and outbreaks of measles.

What does the cell theory emphasize about cells?

All cells arise from pre-existing cells, and anything subcellular is considered non-living.

What are the characteristics of prokaryotic cells?

They lack a nucleus and organelles, with DNA concentrated in a nucleoid region.

What are the characteristics of eukaryotic cells?

They contain a nucleus and organelles, with multiple linear chromosomes.

What factors contribute to public distrust in health systems regarding vaccinations?

Misinformation and vaccine hesitancy.

What vaccination coverage percentage is required for herd immunity?

Approximately 94-95%.

What are common symptoms of Salmonella infection?

Fever, diarrhea, and abdominal cramps.

What types of data do public health officials collect during Salmonella outbreaks?

Epidemiologic data, laboratory confirmations, and traceback data.

What is the role of PulseNet in managing foodborne illness outbreaks?

It detects and tracks outbreaks by comparing DNA fingerprints of bacteria.

How does PulseNet enhance public health responses to outbreaks?

By identifying the source of contamination and preventing further spread.

What is the Hendra virus and how does it transmit to humans?

A zoonotic virus that spreads from fruit bats to horses and then to humans.

What challenges exist in isolating new viruses like Hendra?

Low case numbers, similarities to other viruses, and the need for advanced laboratory tools.

Why are intermediate hosts important in zoonotic diseases?

They amplify the viral load, increasing the risk of human exposure.

How is the Ebola virus transmitted to humans?

Through direct contact with infected body fluids.

What is a significant risk factor for Ebola virus transmission?

Human-wildlife interactions.

Why is identifying the reservoir host of Ebola critical?

It is essential for controlling and preventing outbreaks.

What ethical considerations are associated with bushmeat consumption?

It poses public health risks due to zoonotic spillover.

What types of microorganisms are classified as bacteria?

Bacteria, archaea, fungi (yeast, mold), and protozoa.

What is the magnification capacity of light microscopes used in microbiology?

Up to 1,000X.

What is the purpose of Gram staining in microbiology?

To classify bacteria into Gram-positive and Gram-negative based on cell wall structure.

How can bacteria be classified morphologically?

By shape (cocci, bacilli, spirilla) and arrangement (streptococcus, staphylococcus).

Give examples of bacteria and their classifications.

Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Streptococcus pyogenes (S. pyogenes).

What is the importance of understanding bacterial morphology?

It is essential for identification and treatment of bacterial infections.

What is the significance of aseptic technique in microbiology?

It prevents contamination from pathogens during experiments.

What safety protocol should be followed in laboratory settings regarding bacteria?

All bacteria should be treated as if they are capable of causing disease.

When was the Hendra virus first identified and in which animal?

In 1994, first identified in horses.

What are the reservoir hosts of the Hendra virus?

Flying foxes (Pteropus bats) that carry the virus without showing symptoms.

How do horses contribute to the transmission of the Hendra virus to humans?

They act as amplifying intermediate hosts, spreading the virus through bodily fluids.

How is the Hendra virus transmitted to horses?

Via bites or exposure to infected bat excretions.

What significant outbreak is associated with the Hendra virus?

The 1994 outbreak, which was the first documented case in humans.

What is a spillover event?

A spillover event occurs when a pathogen jumps from one species to another.

What does zoonosis refer to?

Diseases that can be transmitted from animals to humans, accounting for approximately 60% of all human infectious diseases.

Name three examples of zoonotic diseases.

Influenza, rabies, and Ebola.

What role does human activity play in spillover risks?

Human activity, such as habitat destruction and wildlife trade, increases spillover risks.