Zoonotic Diseases & Control Lecture Notes

A collection of flashcards covering key concepts from the lecture on zoonotic diseases and control, especially focusing on Vibrio species, Clostridium, Toxoplasma, and other pathogens.

What are the characteristics of Vibrio bacteria?

Gram-negative, curved rod shape, facultative anaerobes, motile with flagella, acid sensitive, broad pH range (pH 7.0-9.0), and temperature range (18-37℃).

What are the major sources of Vibrio cholerae infections?

Fresh and salt water, particularly through the consumption of undercooked seafood and contaminated water or food.

Which species of Vibrio is the causative agent of cholera?

Vibrio cholerae.

What is cholera toxin and how does it affect the body?

Cholera toxin (CT) is an enterotoxin from Vibrio cholerae that induces severe watery diarrhea by increasing cAMP levels, leading to hypersecretion of fluids and electrolytes.

What are the common symptoms of cholera?

Symptoms include vomiting, cramps, and watery diarrhea (up to 1L/hour), with a high infectious dose required for infection.

What populations are most at risk for Vibrio cholerae infections?

Individuals with low gastric acid levels, children, the elderly, and specific blood types (O blood type is most susceptible).

How does Vibrio cholerae colonize the intestine?

It must survive gastric passage, overcome intestinal peristalsis, penetrate the mucous layer, and establish contact with epithelial cells, followed by production of cholera toxin.

What are the main virulence factors of Vibrio cholerae?

Cholera toxin (CT) and toxin-coregulated pilus (TCP).

Which species of Vibrio is associated with wound infections?

Vibrio vulnificus.

What is the main treatment for cholera?

Fluid and electrolyte replacement, possibly with antibiotics.

What is the prevention method for Vibrio parahaemolyticus infections?

Avoiding undercooked seafood and ensuring proper shrimp/cooking procedures to eliminate the bacteria.

How is Clostridium botulinum classified?

As a spore-forming, gram-positive, obligate anaerobe.

What is the mechanism of action of botulinum toxin?

It inhibits acetylcholine release at the neuromuscular junction, leading to flaccid paralysis.

What are the symptoms of botulism?

Symptoms include blurred vision, drooping eyelids, slurred speech, dry mouth, and progressive muscle weakness.

How can one contract Toxoplasma?

By ingesting oocysts from contaminated food, water, or poorly handled cat litter.

What are the main features of the FDA regulations on fecal microbiota transplantation (FMT)?

FMT is classified as a biologic product, requiring appropriate consent, donor screening, and safety procedures.

What animal is the definitive host for Toxoplasma gondii?

Cats, where oocysts are shed in their feces.

What preventive measures can be taken to avoid zoonotic diseases from pet dogs?

Good hygiene practices, deworming, and not allowing dogs to access contaminated environments.

What is Cryptosporidium and how does it infect hosts?

Cryptosporidium is a protozoan that infects the intestinal epithelium, causing gastrointestinal illness.

What do vaccines provide against zoonotic diseases?

Vaccines stimulate protective immune responses against specific pathogens, establishing immunological memory.