Diseases Transmitted by Man's Best Friend: The Dog.

The relationship between dogs and humans is ancient and mutually beneficial. Dogs have served people well as companions, workmates, guides, and protectors. However, on occasion, dogs may injure humans through biting or may transmit pathogens resulting in a large number of problems ranging from a trivial rash to life-threatening bacteremia. Given that there are more than 80 million pet dogs in the United States, it is worth knowing the potential problems that can result from canine exposure. Annually, almost 5 million people in the United States suffer a dog bite. Dog bite wounds become infected up to 15% of the time. In those who have had a splenectomy, a dog bite may transmit the bacterium Capnocytophaga canimorsus, leading to life-threatening bacteremia. Other illnesses that humans can acquire from dog contact include ringworm, diarrheal disease (salmonellosis, campylobacteriosis, and intestinal parasites), leptospirosis, brucellosis, Q fever, visceral larva migrans, and echinococcosis. Evidence exists that the family dog may serve as a reservoir for uropathogenic Escherichia coli that can lead to urinary tract infections among human household contacts. In this article we discuss dog-related infectious diseases as well as measures to minimize dog-associated illness (e.g., do not disturb sleeping dogs; HIV-infected persons who wish to acquire a puppy should have the dog's stool checked for Cryptosporidium).

Learn to Look and Be a Better Doctor.

Osler advised physicians to "learn to see." Visual intelligence, an ability to look carefully, to be attentive to the visible information in one's environment, and to articulate that information to others, is a skill that can be learned. Being a skilled observer, seeing the world the way an artist might see it, can make one into a more skilled physician.

What's hot in the anaerobe literature? Bacteroides and other non-clostridial anaerobes.

The vast microbiota in the human body is dominated by anaerobic gram-negative rods. The five recent publications reviewed here demonstrate important roles for Bacteroides species and other anaerobic bacteria both in the production of illness and the maintenance of health.

Cutaneous listeriosis.

Cutaneous infections due to Listeria monocytogenes are rare. Typically, infections manifest as nonpainful, nonpruritic, self-limited, localized, papulopustular or vesiculopustular eruptions in healthy persons. Most cases follow direct inoculation of the skin in veterinarians or farmers who have exposure to animal products of conception. Less commonly, skin lesions may arise from hematogenous dissemination in compromised hosts with invasive disease. Here, we report the first case in a gardener that occurred following exposure to soil and vegetation.

Central nervous system infection with Listeria monocytogenes.

The foodborne pathogen Listeria monocytogenes has a particular tropism for the central nervous system and can produce infection in the meninges and brain substance. Well-recognized clinical syndromes include meningitis, brain abscess, rhombencephalitis, and spinal cord abscess; simultaneous infection of the meninges and brain is common. Although it is an uncommon cause of infection in the population at large, L. monocytogenes is an important cause of central nervous system infection in those with impaired cell-mediated immunity, whether due to underlying disease or treatment with immunosuppressive therapeutic agents; it is the etiology in 20% of bacterial meningitis cases in neonates and in 20% of cases in those older than 50 years. Ampicillin is considered the treatment of choice, and trimethoprim-sulfamethoxazole is recommended for those allergic to penicillin. At-risk patients should be advised to avoid unpasteurized milk and soft cheeses along with deli-style, ready-to-eat prepared meats, particularly poultry products.

Gastroenteritis due to Listeria monocytogenes.

It has been known for a long time that many patients experience diarrhea antecedent to the development of bacteremia or meningoencephalitis due to Listeria monocytogenes, but it was only recently that convincing evidence was obtained that this organism can cause acute, self-limited, febrile gastroenteritis in healthy persons. At least 7 outbreaks of foodborne gastroenteritis due to L. monocytogenes have been reported. Illness typically occurs 24 h after ingestion of a large inoculum of bacteria and usually lasts 2 days. Common symptoms include fever, watery diarrhea, nausea, headache, and pains in joints and muscles. L. monocytogenes should be considered to be a possible etiology in outbreaks of febrile gastroenteritis when routine cultures fail to yield a pathogen.