Disease Agents

Question 1

What bacteria causes Q fever?

Answer 1

Coxiella burnetii, Gram negative bacteria, obligate intracellular parasite

Question 2

What is Q fever?

Answer 2

respiratory disease(inhaled), high fever (104-105), originally- slaughterhouse workers in Australia, etiology -(query fever), most infectious disease in the world(treatable with antibiotics)

Question 3

What is Coxiella burnetti used for?

Answer 3

the standard for pasteurization of milk, heat resistant

Question 4

What is a virus?

Answer 4

Infectious agent, unable to grow outside host, obligate parasite, multiply inside living cells, single type of nucleic acid (DNA or RNA, not both), contains a protein coat

Question 5

How many people can touch a doorknob and transfer a virus?

Answer 5

14 successive via doorknob and 6 from original person

Question 6

What is the main difference between bacteria and viruses?

Answer 6

intracellular parasite and pass through bacteriological filters

Question 7

What are the predominant viruses that can cause illnesses?

Answer 7

Astrovirus, Rotavirus, Sapovirus, Norovirus, Hepatitis A virus

Question 8

When and where was Norovirus emerged?

Answer 8

1968 in Norwalk, OH, previously known as Norwalk or Norwalk-like viruses(NLV), RNA virus

Question 9

How is Norovirus transmitted?

Answer 9

Primarily thru the fecal-oral route, person-to-person, fomites, contact surfaces, foods, Highly Contagious

Question 10

What is the infectious dose for Norovirus?

Answer 10

10-100 viral particles

Question 11

What is the cause of the most common cause of acute gastroenteritis?

Answer 11

Norovirus “stomach flu” , 5.5 million cases/yr US (set)

Question 12

What are the symptoms for Norovirus?

Answer 12

humans are the only known host, onset 24-72 hours, Primary: nausea and vomiting, secondary:diarrhea, abdominal pain, headache, low grade fever, duration: typically 12-72 hours,

infected- contagious from onset of feeling ill, up to 2 weeks after recovery

Diagnosed by RT-PCR

Question 13

What is the infectious Hepatitis?

Answer 13

Hepatitis A vrius, Picornavirus

Question 14

What does Picornavirus stand for?

Answer 14

pic=small + RNA + virus

Question 15

What are the symptoms for Hepatitis A virus?

Answer 15

replicates in the liver, 2 weeks before onset, onset 15-50 days, average 30 days, fever, nausea, anorexia, jaundice

Duration: 1-2 weeks, slow recovery
more common in adults

Diagnosis: immunassays

Question 16

How is Hepatitis A virus transmitted?

Answer 16

Infected food handler, fecal-oral-route, person-to-person, contaminated food- raw shellfish, contaminated H20, contaminated food surfaces

Question 17

How can you control Hepatits A virus?

Answer 17

Heat for 10 in @ 80 C to reduce 4.3 logs, inactivated by 70% EtOH or 10 ppm free residual chlorine, immunoglobin within 2 weeks of exposure

Question 18

What is Amebiasis?

Answer 18

parasitic protozoa, Amoebic dysentery, Entamoeba histolytica, from contaminated food, water, hands, only 10-20% of infected people become sick

Question 19

What are the symptoms from Amoebic dysentery?

Answer 19

severe diarrhea, treated with amebicidal drugs, looks similar to cells

Question 20

What do Cryptosporidium parvum cause and it’s symptoms?

Answer 20

cryptosporidiosis, 2-10 days, self limiting, microscopic examination of stool. (acid sating, fluorescent antibodies, PCR

Question 21

What major case had to deal with Cryptosporidium parvum?

Answer 21

Milwaukee, WI-1993, municipal water, >400,000 infected, larger water-borne disease outbreak in US history

Question 22

Describe Cyclospora cayatanensis.

Answer 22

incubation approx. 1 week, duration 10-12 weeks, 11 food borne outbreaks since 1990-US &Canada appr. 3600 people

Question 23

How is Cyclospora cayatanensis treated?

Answer 23

trimethoprim-sulfamethoxazole, fluids and electrolytes

Question 24

What is the leading cause of death in the US?

Answer 24

Toxoplasma gondii (toxoplasmosis)

Question 25

How is Toxoplasma gondii (toxoplasmosis) diagnosed and treated?

Answer 25

direct observation of stained:
tissue sections
cerebrospinal fluid
other biopsy
direct isolation of parasites from blood or other fluids
PCR
Treatment: pyrimethamine and sulfadiazine

Question 26

What are Mycotoxins?

Answer 26

toxins produced by molds as secondary metabolites, formed when large pools of primary metabolic precursor( amino acids, acetate, pyruvate) accumulate

Question 27

Why are mycotoxins produced?

Answer 27

synthesized to remove primary precursors, initiallized at onset of stationary phase, occurs with lipid synthesis