The Centers for Disease Control and Prevention (CDC) has issued a study about a trichinellosis outbreak in California last year that was linked to consumption of privately raised raw boar meat. The study was published in the Morbidity and Mortality Weekly Report for the week of March 2, 2018.
In January 2017, 12 cases of trichinellosis were reported among people who attended an event in December 2017. Larb, a traditional Loatian raw pork dish, was served. The pork came from a domesticated wild boar which was raised and slaughtered on private farm in Northern California. Leftover samples of the food revealed Trichinella spiralis. Nine of those patients were hospitalized with sepsis. Seven had acute kidney injury.
Trichinellosis is a parasitic infection. It used to be linked to pork in this country, back when pigs were fed garbage and scraps. Strict food standards have reduced the prevalence of trichinellosis in this country, but people who consume raw or undercooked wild game meat and pork from private sources are still at risk.
A doctor notified the Alameda County Public Health Department on January 15, 2017, about a patient with suspected trichinellosis. At least three other family members and friends were also sick with symptoms of fever, abdominal pain, myalgia, diarrhea, and vomiting. More reports of suspected trichinellosis started coming in.
Twenty of the 29 potentially exposed people were interviewed. Clinical and exposure information from all interviewees was collected and medical records for patients with a suspected diagnosis of trichinellosis were requested from hospitals and outpatient providers.
Of the nine patients who were hospitalized, nine had sepsis, a blood infection; seven had acute kidney injury; and two had gastrointestinal bleeding. Eight patients were suspected of having skeletal muscle damage. Six had elevated peak troponin levels, which indicate damage to the myocardium.
Investigators found larvae in an unstained touch preparation from the raw pork; they were identified as Trichinella. Samples were sent to the CDC and were identified as Trichinella spiralis.
The event host who owns the farm where the pig was raised said that swine are only given commercial feed and never cooked meat, uncooked meat, offal, or garbage. But small animals such as chicks did get into the fenced pen are were eaten by the pigs. Small mammals infected with Trichinella could have entered the pen and been consumed.
The host was educated about reducing the risk for trichinellosis by freezing raw meat for 30 days, and by cooking meat to a minimum internal temperature of 160°F to kill the larvae. He said he would not serve raw pork from pigs from his farm in the future.
The study’s authors say that while trichinellosis is rare in the United States, it is a public health threat, especially among populations that consume raw or undercooked wild game meats or pork from noncommercial sources. Home-raised and home-slaughtered swine are not subject to the same safety and inspection standards as commercially produced swine are. And home-raised swine with access to the outdoors can acquire zoonotic parasites, including toxoplasmosis and Ascaris suum, which is large roundworm. Educating people who raise swine for personal consumption may mitigate these risks.
Heaton D, Huang S, Shiau R, et al. Trichinellosis Outbreak Linked to Consumption of Privately Raised Raw Boar Meat — California, 2017. MMWR Morb Mortal Wkly Rep 2018;67:247–249. DOI: http://dx.doi.org/10.15585/mmwr.mm6708a3
