Infectious Disease Flashcards
Define carrier.
(1) Person or animal that harbors the infectious agent/disease and can transmit it to others but does not demonstrate signs of the disease.
(a) [COVID-19 living dormant in your body]
Define contact.
(1) Exposure to a source of an infection; a person who has been exposed. Contact does not imply infection; it implies possibility of infection.
(a) [Sexual contact]
Define contagious.
(1) Capable of being transmitted from person to person by contact or proximity. Does not need or utilize a vector.
(a) [Tuberculosis]
Define host.
(1) An organism that harbors a parasitic, mutualistic, or commensalism guest. The host is the house & the parasite is the freeloader.
(a) [Human]
Define parasite.
(1) An organism that lives on or in a host organism and gets its food from or at the expense of its host. Three main classes of human parasites are protozoa, helminths, and ectoparasites.
(a) [Malaria is a protozoa parasite]
Define pathogen.
(1) An infectious agent or organism that can produce disease.
Define infection.
(1) Invasion of the body tissues of a host by an infectious agent, regardless if it causes disease or not.
(a) [Ebola or Influenza]
Define portal of entry.
(1) A pathway into the host that gives an agent access to tissue that will allow it to multiply or act.
(a) [Respiratory tract, open wound, etc.]
Define reservoir.
(1) A population of organisms or the specific environment in which an infectious pathogen naturally lives and reproduces; usually a living host of a certain species.
(2) [Reservoir is a living creature – ex: Anthrax reservoir are herbivores]
Define zoonosis.
(1) A pathogen that is transmissible from non-human animals (typically vertebrates) to humans.
(a) [Swine Flu, bird flu, turtle flu]
Define epidemic.
(1) An increase, often sudden, in the number of cases of a disease above what is normally expected in that population and area.
(a) [Opioid Epidemic in the U.S.]
Define outbreak.
(1) Carries the same definition of epidemic but is often used for a more limited geographic area.
(a) [Mississippi]
Define endemic.
(1) The constant presence of an agent or health condition within a given geographic area or population.
(a) [Malaria in sub-Saharan Africa]
Define pandemic.
(1) An epidemic occurring over a widespread area (multiple countries or continents) and usually affecting a substantial proportion of the population.
What is Arbovirus (arthropod-borne virus)?
(1) Any of a group of viruses that are transmitted between hosts by
mosquitoes, ticks, and other arthropods.
(a) [Malaria, Dengue WNV, Lyme, RMSF]
What is active immunity?
(1) Resistance developed in response to an antigen (pathogen or vaccine) characterized by the presence of antibody produced by the host.
(a) [JEV]
What is herd immunity?
(1) When a majority of a given group is resistant/immune to a pathogen, they achieve “herd immunity”. This confers protection to unvaccinated or susceptible individuals/group by reducing the likelihood of infection or spread.
(a) [Measles]
What is passive immunity?
(1) Transfer of active humoral immunity of ready-made antibodies produced by another host or synthesized. Passive immunization is used when there is a high risk of infection & insufficient time for the body
to develop its own immune response. Short Term!
(a) [Rabies IG, Tetanus IG, Crofab (Rattlesnake antivenin)]
What is morbidity?
(1) Describes any illness, impairment, degradation of health, chronic, or age-related disease.
(2) High Morbidity = Lower lifespan & high mortality when infected with any pathogen.
What is incubation period?
(1) Time interval from a person being infected to the onset of symptoms of an infectious disease.
(2) [Influenza = 1- 4 days]
What is latency period?
(1) Time interval from a person being infected to the time of
infectiousness of an infectious disease.
(2) [TB is where latency period is important]
What is latency period?
(1) Time interval from a person being infected to the time of
infectiousness of an infectious disease.
(2) [TB is where latency period is important]
What is subclinical infection?
(1) An infection that is nearly or completely asymptomatic. A
subclinically infected person is an asymptomatic carrier of the
infection.
(a) [HIV/AIDS]
What is syndrome?
(1) A combination of symptoms, characteristic of a disease, or health condition; sometimes refers to a health condition without a clear cause. Greek for “concurrence.”
(a) [Acquired Immune Deficiency Syndrome]
What is mortality rate?
(1) Measure of death in a defined population during a specified time
interval, from a defined cause.
(a) The mortality rate of Ebola (defined cause) in Democratic
Republic of Congo (defined population) in 2014 (specified
time interval) was 71%.
What is direct contact (infection)?
(1) Transmission occurs between an infected person and a susceptible person via direct physical contact with blood or body fluids.
(a) Person to Person
(b) Examples: touching, kissing, sexual contact, contact with oral
secretions, or contact with body lesions, etc.
What is indirect contact (infection)?
(1) Transmission occurs when there is no direct human-to-human contact.
(2) Contact occurs from:
(a) Vehicle Borne: Person to contaminated surface/object to
person
(b) Vector Borne: Person to vector (mosquitoes,
flies/mites/fleas/tick/rodent/dogs) to person
What is prodrome?
(1) A prodrome (or prodromal symptoms), often indicate the “onset of a disease” before more diagnostically specific signs and symptoms develop.
Define parasite.
An organism that lives on or in a host organism and gets its
food from or at the expense of its host.
What are the subtypes for parasites?
Three main classes of human parasites are protozoa,
helminths, and ectoparasites.
What is a pathogen?
An infectious agent or organism that can produce disease.
What is an infection?
Invasion of the body tissues of a host by an infectious agent, regardless if it causes disease or not.
(a) [Ebola or Influenza]
How are parasites transmitted?
Transmitted through consumption of contaminated food or
water, bite of an infected arthropod, certain practices, fecaloral-route, person-to-person, and between animals and people.
What is a one-celled organisms that are free-living or harbors on a host?
Protozoa
What is a one-celled organisms that are free-living or harbors on a host?
Protozoa
What groups are protozoa classified into?
1) Sarcodina – The ameba (eg. Entamoeba)
2) Mastigophora – The flagellates (eg. Giardia, Leishmania)
3) Ciliophora – The cilates (eg. Balantidium; the only cilates
protozoan to affect humans)
4) Sporozoa – Non motile adult stage organisms (eg.
Plasmodium, Cryptosporidium). *Cryptosporidium is the
leading cause of waterborne disease in the US.
What are large multicellular organisms visible to the naked eye in adult stage, that are free-living or harbors on a host and invades the GI track, but unable to multiply in humans?
Helminths
What three main groups of soil-transmitted helminths human parasite infections are there?
1) Flatworms (platyhelminths) – Reside in the GI tract. eg. Blood flukes (known as trematodes; eg. shisthosomiasis), and tapeworms (cestodes).
2) Thorny-headed worms (acanthocephalins) – Reside in the
GI tract.
3) Roundworms (nematodes) – Reside in the GI tract, blood,
lymph system or subcutaneous tissues (ie. ascarids, hookworms, pinworms).
What type of organism is an ectoparasite?
Ticks, fleas, lice, and mites that burrow into the skin and remain there for weeks to months. This category broadly including other blood-sucking arthropods such as
mosquitos.
What causes various disease, and more importantly functions as
vectors or transmitters of many different pathogens that causes
morbidity and mortality?
Ectoparasites
What are used for diagnosing parasitic infections?
-Fecal (stool) exam
-Endoscopy/colonoscopy
-Blood tests
-X-ray/MRI
What is the treatment for a parasitic infection?
Treatment is base on the affected organ (ie. GI, Derm, blood, liver),
symptoms, specific parasite, and other disease secondary from
parasite.
