chapter 14

Compromised host

Host with lowered resistance to infection and disease for any reason (for example, malnutrition, illness, trauma, or immunosuppression).

Identify four predisposing factors for disease.

Make the body more susceptible to disease. 1) Short urethra in females 2) Inherited traits, such as the sickle cell gene 3) Climate and weather 4) Fatigue

morbidity, mortality, and notifiable disease

Morbidity: incidence of a specific notifiable disease Mortality: deaths from notifiable diseases Notifiable disease: : physicians are required to report occurrence

Define normal and transient microbiota

Normal microbiota: permanently colonize the host Transient microbiota: may be present for days, weeks, or months

Define pathogen, etiology, infection, and disease

Pathogen: A bacterium, virus, or other microorganism that can cause disease Etiology: the study of the cause of a disease Infection: colonization of the body by pathogens Disease: an abnormal state in which the body is not functioning normally

function of the CDC

1) Collects and analyzes epidemiological information in the United States 2) Publishes Morbidity and Mortality Weekly Report (MMWR) 3) CDC conducts critical science and provides health information that protects our nation against expensive and dangerous health threats, and responds when these arise.

Explain four methods of disease transmission.

1) Contact- Direct: requires close association between infected and susceptible host Indirect: spread by fomites Droplet: transmission via airborne droplets 2) Vehicle: Transmission by an inanimate reservoir (food, water, air) 3) Mechanical transmission: arthropod carries pathogen on feet 4) Biological transmission: pathogen reproduces in vector

List five probable reasons for emerging infectious diseases, and name one example for each reason.

1) Genetic recombination: E. coli O157, avian influenza (H5N1) 2) Evolution of new strains: V. cholerae O139 3) Inappropriate use of antibiotics and pesticides: Antibiotic-resistant strains 4) Changes in weather patterns: Hantavirus 5) Animal control measures: Lyme disease

Contrast human, animal, and nonliving reservoirs, and give one example of each.

1) Human reservoirs: Carriers may have inapparent infection or latent disease, ex. HIV, gonorrhea 2) Animal reservoirs: Some zoonoses may be transmitted to humans, ex: rabies, lyme disease 3) Nonliving reservoirs: grow in the soil, water, ex: botulism, tetanus

Explain how nosocomial infections can be prevented.

1) Preventing direct contact transmission: Hand decontamination, Personal hygiene, Clothing, Masks, Gloves, Safe injection practices 2) Food service and housekeeping at the hospital ensure that the equipment used and all working and storage areas are kept clean

Put the following terms in proper sequence in terms of the pattern of disease: period of decline, period of convalescence, period of illness, prodromal period, incubation period.

1) incubation period- no signs or symptoms 2) prodromal period- mild signs and symptoms 3) period of illness- most severe signs and symptoms 4) period of decline- decrease in signs and symptoms 5) period of convalescence- no signs or symptoms (could be period of opportunistic infection)

Categorize diseases according to severity.

Acute disease: symptoms develop rapidly Chronic disease: disease develops slowly Subacute disease: symptoms between acute and chronic Latent disease: disease with a period of no symptoms when the causative agent is inactive.

Define nosocomial infections and explain their importance.

An infection acquired in hospital by a patient who was admitted for a reason other than that infection. An infection occurring in a patient in a hospital or other health care facility in whom the infection was not present or incubating at the time of admission. This includes infections acquired in the hospital but appearing after discharge, and also occupational infections among staff of the facility.

Categorize diseases according to frequency of occurrence.

Incidence: fraction of a population that contracts a disease during a specific time. Prevalence: fraction of a population having a specific disease at a given time. Sporadic disease: disease that occurs occasionally in a population. Endemic disease: disease constantly present in a population. Epidemic disease: disease acquired by many hosts in a given area in a short time. Pandemic disease: worldwide epidemic.

Contrast normal and transient with opportunistic microbes

Opportunistic microbes: microbes that are considered normal resident flora when they are in or on one part of the body, but can cause infection if they move out of that area and into or onto another part of the body, ex: Candida albicans.

Classifying infectious diseases

Symptom: a change in body function that is felt by a patient as a result of disease Sign: a change in a body that can be measured or observed as a result of disease Syndrome: a specific group of signs and symptoms that accompany a disease

Compare commensalism, mutualism, and parasitism, and give an example of each.

Commensalism: one organism benefits, and the other is unaffected. Ex: cattle egrets Mutualism: both organisms benefit. Ex: Bee pollinating a flower- bee can make honey, flower can reproduce. Parasitism: one organism benefits at the expense of the other. Ex: any type of parasite (tapeworm, mite, tick) that attaches to a host (human, animal)

Differentiate between a communicable and a noncommunicable disease.

Communicable disease: a disease that is spread from one host to another. Noncommunicable disease: a disease that is not transmitted from one host to another.

reservoir of infection

Continual source of infection. Can be living organisms such as humans and other animals and nonliving objects or substances that are contaminated with the pathogen.

Define epidemiology and describe three types of epidemiologic investigation.

Epidemiology: The study of where and when diseases occur. Descriptive: collection and analysis of data Analytical: comparison of a diseased group and a healthy group Experimental: controlled experiments