CDC Trichinellosis

nematodes (roundworms)

Trichinellosis (trichinosis) is caused by of the genus Trichinella.

Trichinella

Trichinellosis (trichinosis) is caused by nematodes (roundworms) of the genus ___.

implicated in human disease

Depending on the classification used, there are several species of Trichinella: T. spiralis, T. pseudospiralis, T. nativa, T. murelli, T.nelsoni, T. britovi, T. papuae, and T. zimbabwensis, all but the last of which have been _.

definitive host

Adult worms and encysted larvae develop within a single vertebrate host, and an infected animal serves as a and potential intermediate host.

pigs, anthropophilic rodents, horses

A second host is required to perpetuate the life cycle of Trichinella. The domestic cycle most often involved and __, but other domestic animals such as _ can be involved.

sylvatic cycle

In the __, the range of infected animals is great, but animals most often associated as sources of human infection are bear, moose and wild boar.

undercooked meat

Trichinellosis is caused by the ingestion of __________ containing encysted larvae (except for T. pseudospiralis and T. papuae,
which do not encyst) of Trichinella species.

cysts

After exposure to gastric acid and pepsin, the larvae are released from the _______ invade the small bowel mucosa where they develop into adult worms and Females are 2.2 mm in length males 1.2 mm.

small vowel mucosa

After exposure to gastric acid and pepsin, the larvae are released from the cysts invade the______ where they develop into adult worms and Females are 2.2 mm in length

2.2, 1.2

Females are ______mm in length males _____ mm.

striated muscles

After 1 week, the females release larvae encyst that migrate to

serology

Diagnosis is usually made based on clinical symptoms, and is confirmed by _ or identification of encysted or non encysted larvae in biopsy or autopsy specimens

Ingestion of Undercooked Meat

Infective Stage

Encysted Larva in striated Muscles

Diagnostic Stage

Larva of Trichinella

Figure F: _______liberated from bear meat. This larva is from a different case than those shown in Figures A-D