assignment #1 - Infection

Question 1

4 major portals of entry for infection

Answer 1

• penetration
• direct contact
• ingestion
• inhalation

Question 2

Penetration as a portal of entry for infection

Answer 2

when body’s barrier is broken (mucous membranes or skin) possibility of microorganisms entering ex. breaks causing injury such as burns, abrasions, surgery or catheterazation

Question 3

Direct contact as a portal of entry for infection

Answer 3

A few pathogens are transmitted directly from infected tissue/secretions to exposed intact mucous membranes ex. STI’s from intimate contact

Question 4

Ingestion as a portal of entry for infection

Answer 4

entry of microorganims through oral cavity & gastrointestinal tract ex. many bacterial, viral & parasitic infections such as cholera, dysentry, food poising

Question 5

Inhalation as a portal of entry for infection

Answer 5

Breathing in pathogenic material into respiratory tract

Question 6

respiratory tract has many defenses for pathogens entering

Answer 6

• respiratory tree covered in mucus, gets swept away from lungs to mouth by beating motion of cilliated epithelial cells
• coughing
• respiratory secretions have antibodies & enzymes (can inactivate pathogen)

Question 7

Stages of Disease course

Answer 7

• Incubation period
• prodromal stage
• acute stage
• convalescent stage
• resolution stage

Question 8

Incubation period of disease course

Answer 8

-pathogens begin active replication though not producing any recognizable symptoms

Question 9

prodromal stage of disease coure

Answer 9

-first symptoms appear

Question 10

acute stage of disease course

Answer 10

host experiences maximum impact

Question 11

convalescent period of disease course

Answer 11

infection contained –progressive elimination of pathogen

Question 12

resolution stage of disease course

Answer 12

• total elimination of pathogen

- no residual signs or symptoms of disease

Question 13

subclinical/subacute illness goes through disease process from infection to resolution without

Answer 13

clinically apparent symptoms

Question 14

Local manifestations of infection

Answer 14

• diarrhea
• rash
• convulsions
• hemmorhage
• pneumonia

Question 15

systemic manifestations of infection

Answer 15

• fever
• myalgia (pain in muscles)
• headache
• lethargy

Question 16

Antibacterial drugs

Answer 16

-antibiotics, cause irreversible & deadly damage to the bacteria pathogen

Question 17

Four basic mechanisms of antibiotic actions are

Answer 17

• interference with specific step in bacterial cell wall synthesis
• inhibition of bacterial protein synthesis
• interruption of nucleic acid synthesis
• interference with normal metabolism

Question 18

3 primary laboratory techniques for definitive diagnosis

Answer 18

• culture
• serology
• DNA & RNA sequencing

Question 19

Culture

Answer 19

• growing of microorganism’s outside of the body

- specimen grows on agar plate till microorganism’s grow till detectable

Question 20

Serology

Answer 20

• identity of infectious agents by measuring serum antibodies in diseased host
• tentative diagnosis can be made if antibody level (antibody titre) rises during acute phase of disease & falls during convalescent period
• not as accurate as culture

Question 21

DNA & RNA sequencing

Answer 21

-identifying infectious agents through detection of DNA or RNA sequences that are unique to a single agent

Question 22

Antiviral drugs

Answer 22

-mainly target the viral RNA or DNA of pathogens. Their aim is to inhibit replication of the virus or to inhibit viral enzyme activity (microbe =viruses)