An ongoing dialogue on HIV/AIDS, infectious diseases,
August 13th, 2017
Dog-Related Infectious Diseases as an Excuse to Show Pictures of Dogs
For proof that we’re not like other human members of the planet, when ID doctors think of dogs, it sometimes brings to mind one or more of following associations:
- Gastroenteritis due to Campylobacter jejuni. No, there’s nothing cuter in the world than a puppy — but remember that these little critters are particularly predisposed to symptomatic (and asymptomatic) campylobacter infection, and, given our inability to resist picking up puppies and cuddling them, not surprisingly can be the source of human infection as well. Older dogs are less susceptible, so probably best to keep the puppies out of the elder care facilities.
- The wonderfully named bacterium Capnocytophaga canimorsus. This is a rare cause of sepsis after dog bites — in particular in people without spleens, those who consume too much alcohol, and the immunocompromised. A good trivia question for parties is to ask someone the bug’s original name, which was “DF-2”, standing for “Dysgonic fermenter.” Then ask them what “dysgonic” means. Then ask the difference between “DF-2” and “DF-1”. That will make you the life of the party. (For the record, I have no idea what “DF-1” is.)
- Dogs are the “definitive host” of Echinococcus granulosus. This parasitic infection (which can cause nasty cystic lesions in the liver, lungs, and brain) is most common in people who raise sheep, which like humans act as intermediate hosts. But dogs are required to complete the life cycle, and they get infected when they eat discarded meat and internal organs from echinococcus-infected sheep. That might be yuck to us, but it’s no doubt yum to them. Here’s the CDC-approved life cycle diagram, if you don’t believe me.
- Rabies. (Cue scary music here.) Even though there hasn’t been a human case of rabies linked to a dog bite sustained within the USA in decades, every ID doctor frequently receives calls about dog bites and the risk of rabies. That’s not surprising since 1) dog bites still account for over 90% of human cases world-wide; 2) rabies is nearly 100% fatal, and; 3) there are anti-vaccine crackpots who have spread their nonsense to their dogs. Couldn’t make this stuff up.
Of course that’s hardly the full list — there’s Dipylidium caninum (dog tapeworm), Ancylostoma caninum (dog hookworm), Microsporum canis (ringworm), Brucella canis (transmitted to humans when infected pregnant dogs have spontaneous abortions), and Ehrlichia canis (the cause of ehrlichiosis), just to list those that have the Latin root for dog in their name.
And we could on with several other infections that, in various settings, have been linked to dogs. A true potpourri of zoonoses! There’s giardiasis, Yersinia pestis (yes, that’s the plague), leptospirosis, Pasteurella multocida (though cats really deserve most of the blame for this one) — even MRSA!
Which brings me to the real reason for this post, which is to show three pictures of dogs that struck me as particularly fetching, infectious risks of owning these beasts notwithstanding. First, my friends just got an adorable puppy named Elijah — and here he is.
Second, and just so someone close to me won’t get jealous, here’s a recent picture of a very vigilant Louie, who has clearly spotted some danger in the distance (or maybe just a squirrel).
Third, I happen to work with Francisco Marty, who is not only a remarkable clinician and clinical researcher, but also one extraordinary photographer. And below is proof, entitled “DUMBO’s Dachshund!”