MICR315 - Protozoa and Prions

Question 1

What are foodborne parasites?

Answer 1

Foodborne parasites are tiny organisms that require a living host for growth and nourishment, and they can be found in various food items.

Question 2

What are the types of foodborne parasites?

Answer 2

1. nematodes (roundworms),
2. cestodes (tapeworms),
3. protozoa,
4. Giardia duodenalis,
5. Toxoplasma gondii, and
6. Entamoeba histolytica.

Question 3

What is the source of nematodes?

Answer 3

Nematodes are associated with:
- uncooked or rare fish,
- escargot, and similar foods.

Trichinella spiralis, a type of nematode, is associated with undercooked pork.

Question 4

Which parasites are considered cestodes?

Answer 4

• Cestodes are parasites that can be found in pork and beef.
• Taenia solium (pork) and T. saginata (beef) are common types of cestodes.
• Diphyllobothrium latum is another type associated with raw or rare fish.

Question 5

What are protozoa?

Answer 5

• Protozoa are single-celled organisms that can cause serious illness in humans.
• They include Cyclospora cayetanensis and Cryptosporidium parvum, which are associated with specific foods like berries, basil, water, and unpasteurized apple cider.

Question 6

What are other parasites found in food?

Answer 6

• Giardia duodenalis,
• Toxoplasma gondii,
• Entamoeba histolytica.

Fresh fruits are often the source of these infections, and Toxoplasma gondii can be spread by raw or undercooked meat.

Question 7

How can foodborne parasites be spread?

Answer 7

• can be found in various food items, including meat, fish, vegetables, and fruits.
• Protists can be spread in foods contaminated by fecal matter in water used for washing, irrigating, or spraying crops.
• It is important to practice good hygiene and food safety measures to prevent infections.

Question 8

What is giardiasis?

Answer 8

• an illness caused by the protozoan Giardia lamblia, G. duodenalis, or G. intestinalis.
• characterized by prolonged diarrhea, nausea, abdominal cramps, weakness, weight loss, and other symptoms.

Question 9

How is giardiasis diagnosed?

Answer 9

• microscopic examination of stool samples,
• PCR,
• serological fecal tests

Question 10

What is the treatment for giardiasis?

Answer 10

metronidazole and nitazoxanide.

Question 11

What are the characteristics of cryptosporidiosis?

Answer 11

• caused by the protozoan Cryptosporidium parvum or C. hominis.
• It can contaminate fruits and vegetables through the use of contaminated wash water or by an infected food handler through the fecal-oral route.

Question 12

What are the symptoms of cryptosporidiosis?

Answer 12

• cholera-like diarrhea lasting for 10 to 14 days,
• abdominal pain,
• low-grade fever,
• vomiting.

Question 13

How is cryptosporidiosis diagnosed?

Answer 13

FA tests or immunoassay tests.

Question 14

What is the treatment for cryptosporidiosis?

Answer 14

Nitazoxanide

Question 15

How can amoebic dysentery (amoebiasis) be prevented?

Answer 15

• proper sanitation and hygiene practices,
• safe food and water precautions,
• avoiding high-risk behaviors,
  -screening and treating infected individuals and their contacts,
• proper disposal of fecal matter,
• education and awareness programs

Question 16

What is the pathogenesis of Entamoeba histolytica?

Answer 16

• the parasite that causes amoebic dysentery, invades the intestinal mucosa, causing inflammation and ulceration.
• It can spread to other organs through the bloodstream, leading to abscesses.

Question 17

What are the complications of amoebiasis?

Answer 17

Complications of amoebiasis include:
1. intestinal perforation and peritonitis,
2. liver abscesses,
3. pulmonary abscesses,
4. brain abscesses,
5. genital amoebiasis,
6. chronic amoebiasis

Question 18

What is the treatment for amoebiasis?

Answer 18

metronidazole,
tinidazole,
paromomycin,
iodoquinol.

Question 19

How can amoebiasis be prevented from spreading?

Answer 19

proper treatment, sanitation, and hygiene practices

Question 20

What are the commonalities between the foodborne parasites Cyclospora, Cryptosporidium, and Entamoeba histolytica?

Answer 20

• all intestinal protozoan parasites that can infect humans through contaminated food or water.
• They are resistant to chlorination and can cause gastrointestinal symptoms.

Question 21

How can foodborne parasitic diseases be prevented in general?

Answer 21

• proper cooking of meat and seafood,
• frequent handwashing, avoiding cross-contamination,
• washing fruits and vegetables,
• educating the public on safe food handling,
• implementing sanitation practices in food processing.

Question 22

What is Bovine Spongiform Encephalopathy (BSE), also known as mad cow’s disease?

Answer 22

• BSE is a fatal neurological disease in cattle caused by prions.
• It leads to a conformational change in brain proteins, resulting in the degeneration of neural tissue and the formation of plaque in the brain.

Question 23

What is variant Creutzfeldt-Jakob disease (vCJD)?

Answer 23

• vCJD is a fatal, dementia-like illness in humans that is associated with the consumption of meat from cattle infected with BSE.
• It causes psychiatric problems, sensory abnormalities, and progressive dementia.

Question 24

How is BSE diagnosed in animals and humans?

Answer 24

• Diagnosis is typically made by examining the brain tissue of affected animals or humans after death.
• In live animals, testing involves the detection of abnormal prion proteins in body fluids.
• MRI imaging can also be used to detect brain changes in humans with vCJD.

Question 25

What is the treatment for BSE and vCJD?

Answer 25

There is no known treatment or cure for BSE or vCJD. These diseases are fatal once symptoms develop.

Question 26

How did the BSE outbreak spread?

Answer 26

The largest outbreak of BSE occurred in the United Kingdom in the 1980s and 1990s. It spread to other countries through cattle breeding and the use of contaminated meals. Other countries, such as Canada, Japan, and the United States, have also experienced isolated cases of BSE.

Question 27

What are the preventative measures for BSE?

Answer 27

• removing specified risk materials (SRMs) from the food chain,
• avoiding the use of contaminated meat and bone meal as feed,
• proper disposal of animal remains,
• decontamination of equipment.

Question 28

What is Creutzfeldt-Jakob disease (CJD)?

Answer 28

• CJD is a progressive, degenerative nervous system disease that affects humans.
• It belongs to the family of transmissible spongiform encephalopathies (TSEs) and primarily affects older individuals.

Question 29

How is CJD different from variant CJD (vCJD)?

Answer 29

• Variant CJD is a form of CJD diagnosed in the UK that affects younger individuals.
• It is associated with extensive plaque formation in the brain tissue and has different clinical characteristics compared to classical CJD.

Question 30

How is vCJD linked to the ingestion of meat?

Answer 30

• Variant CJD is linked to the consumption of meat from cattle suffering from BSE.
• The transmission occurs through nerve tissue rather than muscle, so contaminated meat contains nervous system tissue such as the brain, spinal cord, or dorsal root ganglia.

Question 31

What initiatives were implemented in the US to prevent BSE?

Answer 31

In the US, initiatives such as making BSE a notifiable disease, banning live animals from BSE countries, surveillance of cattle brains, prohibiting mammalian protein in ruminant feed, and banning the import of rendered protein from Europe were implemented to prevent BSE.

Question 32

What are the risks associated with BSE and the safety of the food supply?

Answer 32

BSE is categorized as low risk which suggests changes in manufacturing practices