Culture Shock: Of Dog Bites and Diarrhea, Eels and Oysters

If you're worried about dog bites and diarrhea, don't travel to northern Africa. Here at home, eels and oysters might be a concern.


That's what you might draw from the April issue of the CDC's journal Emerging Infectious Diseases.

MedPage Today doesn't usually cover EID. We're a news organization and pretty much by definition the journal includes reports on things that might one day be news but aren't right now -- rather like the "little cloud out of the sea" that portends a mighty storm.

(That's the first book of Kings (18:44), by the way, and the phrase "no bigger than a man's hand" does not appear in the verse. I looked it up.)

Now it's unlikely that dog bites in northern Africa will ever develop into an international crisis, but still -- if you're traveling it's useful to know what to expect.

That why members of the GeoSentinel Surveillance Network analyzed records of 16,893 ill travelers returning from Africa over a 14-year period.

The bottom line was that travelers to northern Africa most commonly reported dog bites and gastrointestinal illnesses, while those who had been in sub-Saharan Africa reported fevers.

The type of illness varied, with malaria predominating in central and western Africa, the researchers found. Eastern and western Africa had schistosomiasis, strongyloidiasis, and dengue, while loaisis was mostly reported from central Africa. All told, 11 travelers died, all of malaria.

Researchers from the U.S. Geological Survey and St. Norbert College in Wisconsin concerned themselves with eels -- specifically, Asian swamp eels. The squirmy critters are used as food in parts of Asia and are imported to the U.S. for ethnic food markets. There are also wild populations in several states.

The problem is that they are a common source of gnathostomiasis, a zoonosis that causes a range of symptoms, but can lead to paralysis and death.

Sure enough, the researchers found that 13 of the 47 market eels they tested were infected with the nematode Gnathostoma spinigerum, while four of 67 wild eels were carrying other Gnathostoma species.

So watch out for eels.

You might also want to be careful of oysters, which -- I did not know this -- can carry a pandemic strain of Vibrio parahaemolyticus. That's the same genus as cholera and the symptoms are similar although not usually life-threatening: watery diarrhea, nausea, vomiting, fever, and chills.

We don't usually think of pandemic oysters but the V. parahaemolyticus clone complex in question, O3:K6, has been causing disease from Taiwan to the U.S. since at least 2000. And it's usually carried by the tasty bivalves, so I'm going with pandemic oysters.

In a letter to EID, investigators from Baltimore's health department and the FDA show that the O3:K6 complex was responsible for a 2012 outbreak of gastroenteritis in a Maryland restaurant, and possibly for reported illnesses in other states in the same period.

They are naturally concerned, especially since the diners had not actually eaten any oysters, suggesting cross-contamination from the bivalves to other seafood.

Another report in EID is perhaps more concerning, but it doesn't actually involve an emerging disease, but rather one that is re-emerging -- gonorrhea. As MedPage Today has reported extensively, drug-resistant gonorrhea is on the rise, to the point that almost no antibiotics are now reliable cures.

Investigators from the CDC wondered what that increasing drug resistance meant for gonorrhea incidence. Using data from the Gonoccocal Isolate Surveillance Project, as well as city-level incidence rates for 17 cities, they looked at what happened from 1991 through 2006.

The central finding was that resistance to ciprofloxacin (Cipro) in isolates was positively associated with incidence -- the more resistance, the more disease. Of course, that doesn't show that rising resistance causes increased incidence but it's consistent with the idea.

None of this, of course, is front-page news. Nor should it be. The front page is reserved for the big stuff, the bad stuff.

But I'm glad someone is keeping an eye on the little things -- before they get big and bad.

Next Article