Bacteriology - Ch 1 - Parasitism And Pathogenicity - Fall

Front 1

Describe the ecologic arrangement of parasites.

Back 1

living in permanent association with, and at the expense of, animal hosts

Front 2

Describe the ecologic arrangement of saprophytes.

Back 2

normally inhabit the inanimate environment.

Front 3

Define commensals

Back 3

parasites that cause their host no discernible harm

Front 4

What is the difference between symbiosis and mutualism.

Back 4

None, both terms refer to reciprocally beneficial associations of organisms.

Front 5

What are pathogenic organisms? What is their process?

Back 5

Parasites or saprophytes that cause disease.

The process by which they establish themselves in a host individual is infection.

Front 6

What term sometimes is used to mean pathogenicity and sometimes degrees of pathogenicity.

Back 6

Virulence

Front 7

Define infection vs disease.

Back 7

Infection: the presence of one organism within or on another. Also
known as colonization.

Disease: Disease is a process - “a departure from health”- in our case a result of interaction between host/nonhost that results in damage to the host....an end product of an infectious process.

Point here: infection is different that dz. Colonization may not result in any clinical signs.

Front 8

Define pathogen and virulence.

Back 8

Pathogen- a microorganism or virus that can cause disease.

Virulence- a measure of pathogenicity.
Highly virulent pathogen
Low virulence organism
“highly pathogenic” isn’t a proper term.

Front 9

What are the measures of virulence?

Back 9

ID 50: Infectious Dose for 50% of animals.

LD 50: Lethal dose for 50% of animals.

Relative accumulation of organisms in a host. Competitive indices: Infect a host with equal numbers of a wild type and mutant strain, quantify how many of each organism remain in the host after a certain amount of time.

Front 10

What four steps do all bacteria need to do to perpetuate themselves?

Back 10

Enter an environment
Survive
Reproduce
Leave the environment

Front 11

According to Dr. Rockey, which form of symbiosis is most prevalent?

Back 11

mutualism - in which the association is advantageous to both.

Commensalism, in which one member of the association benefits
while the other is not affected, is usually misused. Usually if it's a long-term arrangement, it's likely to be mutualistic.

Front 12

What determines what type of nonhost cells exist in different areas of the body?

Back 12

The host - Nasal cavity, mouth, digestive tract = high numbers of nonhost cells.

Lung, ocular mucosa = _very low_ numbers of nonhost cells.

The nature and type of the organisms in each place are totally unique and different to the area of the body that the host allows to be occupied.

Front 13

Why do ruminants have an acidic stomach?

Back 13

In addition to killing off the pathogens, and digestion, it's also to kill microbes that need to be sequestered in the forestomachs.

Front 14

What % of fecal matter is bacteria?

Back 14

20-25%

Large intestine has ~10^ll bacteria/ml

Front 15

What are the three mechanisms of mutualism in the intestinal tract?

Back 15

1: The __normal flora_ of the intestine-as well as other parts of the body-serve to crowd out bacteria that may do the animal real harm.

2: Intestinal microflora can process foodstuffs not digested previously in the body.

3: In some instances, microflora can produce cofactors that animals cannot (microbial production of ___vit K__ in humans)

intestinal microglora can process foodstuffs not

Front 16

Describe the importance of having the proper gut flora in calves.

Back 16

Calves are particularly susceptible to scours at least partly because their intestinal normal flora has not matured.

Front 17

Endogenous dz vs exogenous dz

Back 17

Endogenous dz: caused by normal flora (shipping fever)

Exogenous dz: caused by outside pathogens.

Front 18

Define parasitism

Back 18

The invading organism benefits from
its interaction with the host, but the host is harmed.