Date: May 20, 2006
Seventeen cases of trichinellosis were detected among members of an extended family living in the state of Mecklenburg-Vorpommern, eastern Germany (see: Google Earth images) between December 2005 and March 2006. On March 21, 2006, health authorities in the district were notified of a laboratory diagnosed case of trichinellosis. The patient, a 30 year old woman, had been admitted to hospital on February 22, 2006 with diarrhea, nausea, fever, facial swelling, and muscle pain. The patient's blood was tested for IgG and IgM antibodies to Trichinella as part of the differential diagnosis, using ELISA.
Trichinella larvae were found in a muscle biopsy using immunoflourescence microscopy. The local health and veterinary authorities suspected that pork from a home-reared pig that had been slaughtered at a local butcher's was the source of infection.
On March 23, a 2nd case was notified in the mother-in-law of the first patient. The 2nd patient had first become ill in December 2005 with unexplained diarrhea, nausea, fever, facial swelling, and muscle pain, and was admitted to hospital for 2 weeks. After the identification of the illness in her daughter-in-law, she was again admitted to hospital from March 21-27, 2006 and Trichinella larvae were identified in the remainder of a frozen muscle biopsy specimen taken in December 2005. The diagnosis was confirmed by serology.
After exchanging information between veterinary and local government authorities, and the Federal Authority for Risk Assessment, the local health authorities contacted 22 people who had all consumed meat and meat products (raw minced pork, uncooked smoked sausage or Mettwurst, and ham or liver sausage) made from the suspect pork flesh. Blood samples from 17 of these people tested positive for Trichinella infection using ELISA; 16 also had clinical symptoms of trichinellosis: 12 had muscle pain and facial or joint swelling, and 10 had diarrhea. Fifteen of these patients were admitted to hospital for treatment. On April 20, a further case of trichinellosis was identified in a 42 year old man, a neighbor of the affected family. The man had also consumed smoked sausage made from the pork from the neighbor's pig. He presented with neurological symptoms including visual disturbances, a suspected stroke due to vasculitis, and peripheral weakness in all limbs. He was treated in a neurological rehabilitation centre. One serologically confirmed case had no clinical symptoms. Four people who consumed the implicated meat did not develop suspect symptoms, and their serology was negative. The newborn child of a mother with trichinellosis also tested negative.
Some bacon left over from the implicated pig was examined for trichinellosis using the digestion method. A high density of Trichinella larvae was identified (106 larvae per gram of bacon). These were characterized with multiplex PCR as Trichinella spiralis. Since 1900, it has been a legal requirement in Germany for commercially slaughtered pigs and other animals that can harbor Trichinella (particularly wild boar and horse) to be inspected for the larvae (since 1937 for home-slaughtered animals). However, there is evidence that this requirement is not always adhered to, particularly when the meat is home-slaughtered, is from wild pigs or is imported. Investigations into how meat from the infected pig was able to pass safety inspections are continuing. Trichinellosis is a rare disease in Germany: 5 cases were reported in 2004, and no cases were reported in 2005.
1. Robert Koch-Institut. Trichinellose: Zu einer Häufung in Mecklenburg-Vorpommern. Epidemiologisches Bulletin 2006; 18: 139-40
Reported by: M Littmann (<email@example.com>) /1, K
Noeckler /2, J Hallauer /1
1/ Landesamt fuer Gesundheit u. Soziales, Rostock
2/ Bundesamt fuer Risikobewertung (Federal Authority for Risk Assessment)