A recent article in MMWR Weekly with the unassuming title of “Preliminary FoodNet Data on the Incidence of Infection with Pathogens Transmitted Commonly Through Food — 10 States, 2008” is incredibly disturbing.
The incidence of reported (more about that in a bit) Salmonella was 16.20 cases per 100,000 people. If we use a population size of 300 million, that means (Mad Biologist takes off shoes to do big number arithmetic) roughly 48,600 people had food associated Salmonella infections.
But it’s probably higher than that, although I have no idea how much higher. For a Salmonella infection to make its way into the FoodNet surveillance system, the following has to happen:
- The illness has to be severe enough for the infected person to seek medical attention. A huge number of infections will be missed, particularly if they clear up (e.g., you spend all night being sick, but feel better–or at least stop vomiting–so you never seek medical help).
- If the person winds up at a doctor’s office or a hospital (or clinic), a sample has to be taken and analyzed. Again, this doesn’t happen that often, particularly if the patient starts to feel better (due to rehydration, for instance).
- The laboratory doing the testing has to be part of the FoodNet network (and report it). This is probably the best step, in that, in the ten FoodNet states, coverage is pretty good, and reporting is pretty reliable.
Like I said, it’s hard to know how underreported this is (for the reasons above), but it’s pretty clear it has to be much higher–and this is only one organism. If you include all of the agricultural-associated organisms (and no viruses are measured), the numbers increase three- to four-fold.
But, don’t worry, there’s very little transmission of bacteria through the food chain. At least, that’s what the ag lobby tells me about antibiotic resistance…
Cited article: Vugia et al. 2008. Preliminary FoodNet Data on the Incidence of Infection with Pathogens Transmitted Commonly Through Food — 10 States, 2008. MMWR Weekly 58(13): 333-337.