Imported human trichinellosis: sequential IgG4 antibody response to Trichinella spiralis.

Two out of five members of one household presented with clinical signs of trichinellosis after their return to the Netherlands. The family had consumed Trichinella-infected pork in Montenegro, formerly Yugoslavia. Serological tests were performed at 1, 2, 6, and 18 months after ingestion of the infected meat. Trichinella-specific IgM, IgG, and IgA antibodies measured in sera from symptomatic and asymptomatic patients remained positive up to 18 months after ingestion. The measured IgG4 antibody response directed to a 45 kDa Trichinella spiralis antigen also persisted 18 months after ingestion for three of the family members.