experimental trichinellosis in horses biological and parasitological evaluation three groups of three horses each were respectively infected with 5000 20000 and 50000 larvae of trichinella spiralis the strain used was isolated from a human biopsy during horsemeatrelated outbreaks of trichinellosis in france transient muscular disorders were only observed in two of the horses infected with 50000 larvae but none of the horses had fever a significant increase in blood eosinophils was noticed in 5 horses serum ldh aldolase and cpk peaked at the fifth week postinfection specific igg assayed by indirect immunofluorescence and elisa appeared 25 weeks postinfection and disappeared between 16 and 40 weeks the distribution of t spiralis larvae was maximal in the tongue masseters and diaphragm but a large decrease in the number of larvae recovered from the muscles was noticed among the horses slaughtered at the beginning and end of the experiment in muscular histological sections larvae were observed in an intramyofibrillar position and were surrounded by a mild to severe inflammatory reaction