Flashcards in Zoonoses from Milk and Water Deck (48)
What are the (3) classic milkborne pathogens?
How do pathogens get into milk?
Bacteria infect the animal systemically and colonize the mammary glands
Bacteria can be secreted into milk in a chronic fashion, often with minimal symptoms in the animal
In addition to milk, there can be _____ transmission to people
Percutaneous or mucous membrane contact with infectious fluids
Who are most at risk for zoonotic infections from organisms in milk?
People who work with infected animals or premises are at highest risk : farmers, veterinarians, and abattoir workers
T/F: Some imported soft cheeses are not pasteurized and therefore, have potential for zoonotic transfer
Where do most cases of M. bovis occur?
Countries without pasteurization of milk or control programs in cattle
Pulmonary TB (M. bovis) cannot be discriminated from M. ________ via skin testing or x-rays, only by ________.
What percentage of "M. tuberculosis" cases in countries that do not pasteurize milk or test cattle are actually M. bovis?
What are the 3 major zoonotic transmission routes of mycobacterium bovis?
Aerosol (from infected cattle to other cattle and to people who work with cattle)
Oral exposure: to milk, feces, LN contents
Percutaneous exposure: abattoir workers, necropsy, etc
How can M. bovis be controlled?
Eliminate the animal reservoir
What clinical signs might you see in a person with Brucellosis?
aka "undulant fever" or "malta fever"
-recurring fever, can last for months
-abortions can occur if pregnant
-Pleiomorphic symptoms: neurological, endocarditis, possibly chronic fatigue
What is the causative agent of Q Fever? What signs might you see in a human infected?
Coxiella burnetii - causes a non specific febrile illness
Abortions if pregnant
Chronic pleiomorphic symptoms
May also present as atypical pneumonia or hepatitis
What is the most pathogenic species of brucella in people?
It infects a variety of animals and is mostly found in the Mediterranean and other intensive goat-farming regions
What brucella species is highly pathogenic in people, and has a worldwide distribution (with the exception of places with successful eradication processes)?
Seen in cattle, bison, buffalo, horses, dogs etc
What two brucella spps are the least pathogenic in humans, but still a zoonotic concern?
B. suis and B. canis
How do people get infected with brucella?
Ingestion, mm exposure , or percutaneous inoculation with: aborted placenta, fetus or fetal fluids, unpasteurized milk, blood, urine, semen, feces, and vaginal secretions
*feed/water contaminated with these materials
What methods are taken to control brucella?
Elimination of the animal reservoir
Reduce public exposure by pasteurization of milk and milk used to make soft cheeses
Is there an eradication program for Coxiella burnetti in the USA?
Greater than 90% of dairy herds in the US have C. burnetii (20-30% of cattle are shedding at any given time)
The basis of pasteurization standards is based upon what pathogen?
**this protects the public but not animal workers/farmers
How is C. burnetti transmitted?
Percutaneous and mm exposure
Is C. burnetti an environmental issue? Why or why not?
It causes abortion - there are large amounts of pathogen in the aborted placenta and fetus: survives in water, soil, milk, and meat for WEEKS TO MONTHS
Chronically excreted in milk and feces (possibly urine)
What are some barriers to control?
Social cost/veterinary infrastructure
Compliance of animal owners
What two protozoa pathogens pose a threat via water transmission?
How long can cryptosporidium and giardia survive in water if conditions are good?
T/F: Chlorinating water will prevent cypto and giardia
**Must FILTER water
What spps of cryptosporidium is zoonotic and has cattle as the reservoir?
Outbreaks are typically rural
Often follow overflow/flooding of animal waste holding ponds or feedlot/dairy pens
What spps of crypto is transferred human to human - during outbreaks in urban municipal water systems?
Sewage tx does not always kill 100% of oocysts
What is the human infecting genogroup of Giardia?
A or B
T/F: Giardia in humans will typical cause acute intestinal infections
giardia will cause chronic intestinal infections. Greasy, foul smelling dhr, weight loss