ID- Respiratory system

Question 1

Respiratory tract and its defenses

Answer 1

Divided into two parts, upper (mouth, nose, nasal cavity, sinuses, pharynx, epiglottis, larynx) and lower (trachea, bronchi, bronchioles, lungs, alveoli). Most common place for infectious agents to gain access to the body. Defenses include nasal hair, cilia, mucous, coughing, sneezing, swallowing, macrophages, secretory IgA against specific pathogens (gives natural immunity).

Question 2

Normal biota of the respiratory tract

Answer 2

Generally located in upper RT. Gram positive bacteria very common. Disease causing bacteria are present as normal biota as they can cause disease if their host becomes immunocompromised or if they are transferred to other body’s hosts that do not consider this normal biota. Normal biota perform microbial antagonism.

Question 3

Diseases caused by microorganisms affecting upper and lower RT

Answer 3

A number of infectious agents affect both regions. Most well known are whooping cough, RSF, and influenza.

Question 4

Influenza

Answer 4

Important to study as it provides illustration of the way other viruses change to cause more serious diseases. Most flus are seasonal and occur annually, not usually associated with pandemics. Some are not seasonal, associated with pandemics, such as H1N1 in 2009.

Question 5

Signs and symptoms of influenza

Answer 5

Begins in upper and some serious cases may affect lower. Occurs rapidly but has a 1-4 day incubation period. Symptoms include headache, chills, dry cough, body aches, fever, stuffy nose, sore throat. Extreme fatigue can last a few days or a few weeks.

Question 6

Causative agent for influenza

Answer 6

Influenza virus including three types, A, B, and C. Enveloped with spikes.

Question 7

Antigenic Drift

Answer 7

Minor antigenic changes in glycoproteins due to mutations in spike genes. Antibody doesn’t bind, not great immunity. Antigenic drift seen in antibody binding spikes with constant mutations.

Question 8

Antigenic Shift

Answer 8

Major changes in the glycoproteins due to recombination of viral strains from two different hosts. 2 decks of cards, blue & red example. Where two viruses infect a single host and new strain is produced in which nobody has immunity to.

Question 9

Virulence factors of influenza

Answer 9

Binds to ciliated cells of respiratory mucosa, causes rapid shedding of cells that are full of viruses, stripping cells eliminates protective ciliary clearance, viruses remain located in respiratory tract.

Question 10

Transmission and epidemiology of influenza

Answer 10

Inhalation of aerosols and droplets are the main mode of transmission. This is facilitated by crowding and poor ventilation. Dry air also aids in helping dry aerosols to droplet nuclei and remain in the air for longer. 36,000 US deaths annually, most die due to underlying illnesses. Mainly the very young and old are susceptible to this.

Question 11

Diagnoses for influenza

Answer 11

Generally diagnosed through symptoms alone. Rapid influenza tests can provide results in 24 hours. Viral culture tests can give results in 3-10 days but usually they are either very ill by then or over it.

Question 12

Prevention of influenza

Answer 12

Flu shot, flumist.

Question 13

Treatment for influenza

Answer 13

Antivirals are available but have to be taken within the 1st or 2nd day of symptoms.