Question

Marvin Williams is a 53-year-old farmer. He, along with the other members of his family, operates the largest dairy in the county. In addition to a wide variety of dairy products (milk, cream, and cheeses), the farm produces eggs, poultry, sausage, bacon, and ham, which are sold locally. Marvin had been in excellent health until approximately 8 weeks ago, when he developed what he thought was the flu. He can’t seem to shake it, so at the insistence of his family, he decides to see Dr. Johnson at the local clinic. At the clinic, Dr. Johnson performs a routine physical examination and takes a medical history. Mr. Williams’s physical examination is fairly unremarkable, with the exception that he appears anorexic, having lost 40 pounds over the past 8 weeks. Mr. Williams complains of flulike symptoms, such as fever, headache, malaise, myalgia (muscle pain), nausea, and vomiting. He also has been experiencing periodic night sweats. Mr. Williams’s medical history is also fairly unremarkable. He has no known allergies or record of previous illness. His immunizations are up to date. He is a nonsmoker and does not drink alcohol. Dr. Johnson inquires whether anyone else in the Williams family is ill with similar symptoms. Mr. Williams indicates to Dr. Johnson that no other family members are ill. Noting Mr. Williams’s occupation, Dr. Johnson then asks whether he or his family members consume products from their farm or dairy. Marvin responds that his family often consumes products they produce and that on multiple occasions he has consumed milk from the cows kept in the pasture. The dairy cows used for milk, cream and cheese production are maintained in a separate enclosed location away from the other cattle and from other farm animals. Dr. Johnson orders blood drawn for a febrile antibodies panel specific for Brucella IgM antibodies, blood cultures, and a PPD (purified protein derivative) skin test. Laboratory Testing Highlights: The febrile antibodies panel is useful for detecting infections associated with Rickettsia, Brucella, and Salmonella typhi. In this case, Dr. Johnson suspects that Marvin may have brucellosis. Isolation of the causative organism would confirm the diagnosis, so blood cultures have been ordered as well. The PPD skin test is often ordered to rule out infection by Mycobacterium species, such as M. tuberculosis or M. bovis. Exposure to either of these agents is indicated by a region of erythema (redness) and induration (hardened skin) within 72 hours of intradermal injection of purified protein derivative of tuberculin. Clinical Background: Brucella species are gram-negative coccobacilli that commonly infect domestic animals, such as pigs (B. suis), goats (B. melitensis), cows (B. abortus), and dogs (B. canis), and wild animals, such as deer, elk, buffalo, and moose. The organism can be cultured in the laboratory, but sometimes isolation is difficult. A direct agglutination test is the principal serological test used to detect antibodies to Brucella spp. Brucellosis has an incubation period of 1 to 3 weeks. Fever, sweats, headache, weakness, and back pain are typical symptoms of milder infections, but complications affecting the central nervous system (CNS) and heart can occur. Mycobacterium bovis causes fewer than 1% of tuberculosis cases in humans. People who consume unpasteurized dairy products have a higher risk for infection, as do individuals with weakened immune systems. Symptoms can include fever, night sweats, weakness, and weight loss. M. bovis may also be cultured and identified in the laboratory.

Of the following food products, which one was the most likely the source of Mr. Williams’s infection?

cheese

raw milk

eggs

cream

Answer 1

Answer is: raw milk

Explanation:

Dr. Johnson order a PPD (purified protein derivative) for Mr. Williams because he wants to find out the bovine tuberculosis possibility. Mr. Williams's consuming unpasteurized infected cow's milk products can cause bovine tuberculosis.

People who consume unpasteurized dairy products have a higher risk for infection, as do individuals with weakened immune systems. unpasteurized dairy products are raw milk.