(3) Chapter 14: Principles of Disease and Epidemiology

What are predisposing factors?

Factors that make an individual more susceptible to developing disease.

How does gender act as a predisposing factor?

Being female increases the risk of urinary tract infections because females have a shorter urethra.

How do inherited traits act as predisposing factors?

Genetic disorders, such as sickle cell anemia, increase susceptibility to certain diseases.

How do climate and weather act as predisposing factors?

Tropical climates support vectors like mosquitoes, increasing diseases such as malaria.

Why is lack of vaccination considered a predisposing factor?

Without vaccination, individuals are more susceptible to infectious diseases.

How does fatigue increase the risk of disease?

Fatigue weakens the immune system, making infections more likely.

How does age affect susceptibility to disease?

The very young and the elderly have weaker immune systems and are more susceptible to infections.

How does lifestyle influence disease susceptibility?

Certain occupations or habits increase disease risk, such as coal miners developing lung disease.

How does poor nutrition increase the risk of disease?

Malnutrition weakens the immune system, making infections more likely.

Why are chemotherapy and radiation therapy predisposing factors?

They suppress the immune system, increasing susceptibility to opportunistic infections.

What is the incubation period?

The interval between the initial infection and the appearance of the first signs or symptoms.

What occurs during the incubation period?

The pathogen is multiplying, but no signs or symptoms are present.

Can a person transmit an infectious disease during the incubation period?

Yes. According to your professor, many diseases can be transmitted before symptoms appear.

What is the prodromal period?

A short stage after incubation in which mild, vague symptoms first appear.

What are examples of symptoms during the prodromal period?

General discomfort, headache, fatigue, or feeling "not quite right."

What is the period of illness?

The stage during which the disease is most severe and signs and symptoms are most pronounced.

What occurs if the immune system cannot overcome the infection during the period of illness?

The patient may die if treatment is not successful.

What is the period of decline?

The stage during which signs and symptoms begin to decrease as the patient improves.

Why are patients especially susceptible to secondary infections during the period of decline?

The immune system is still recovering and has not returned to full strength.

What is the period of convalescence?

The recovery stage during which the body returns to its pre-disease state and strength is regained.

Can a person still transmit disease during convalescence?

Yes. Your professor emphasized that infectious diseases may still be transmitted during recovery.

What is a reservoir of infection?

A continual source of a pathogen from which infection can occur.

What are the three major types of reservoirs?

Humans, animals, and nonliving reservoirs such as soil, water, and food.

How can humans serve as reservoirs of infection?

They can carry pathogens during the incubation period, latent period, convalescence, or active disease and transmit them to others.

What is a carrier?

An individual who harbors a pathogen and can transmit it to others, often without showing symptoms.

How can latent infections make humans reservoirs?

The pathogen remains in the body even when symptoms are absent and may still be transmitted or reactivate later.

How do animals serve as reservoirs of infection?

Animals can harbor pathogens that are transmitted to humans, causing zoonotic diseases.

What is a zoonosis?

A disease transmitted from animals to humans.

How can zoonotic diseases be transmitted?

Through direct contact with animals, animal bites, animal waste, or vectors associated with animals.

What nonliving materials can act as reservoirs?

Soil, water, and food.

Why is soil considered a reservoir of infection?

It contains pathogens such as fungal spores and Clostridium species.

Which Clostridium species did your professor mention as soil reservoirs?

Clostridium tetani and Clostridium botulinum.

Why is water considered a reservoir of infection?

It can contain pathogens that cause diseases when contaminated water is consumed.

What waterborne diseases did your professor mention?

Cholera, shigellosis, salmonellosis, cryptosporidiosis, and diseases caused by parasitic helminths.

Why is food considered a reservoir of infection?

Food can become contaminated, improperly stored, undercooked, or cross-contaminated with pathogens.

What is cross-contamination?

The transfer of pathogens from one food or surface to another, such as using the same knife on raw meat and vegetables.