Experimental trichinellosis in horses: biological and parasitological evaluation.

This research article examines the effects of different levels of Trichinella spiralis larvae infection in horses, observing a wide variety of effects on the horses’ bodily functions and immune responses. The experiment involved three groups of horses infected with differing numbers of the parasite’s larvae and tracked their conditions for weeks.

Research Method

• The research team infected three separate groups of horses with Trichinella spiralis, a common parasite known to affect mammals. Each group received a different amount of larvae: 5000, 20000, and 50000.
• The strain of Trichinella spiralis used in this study was extracted from a human during a horse-meat related trichinellosis outbreak in France.

OBSERVATIONS AND FINDINGS

• Only two horses, both from the group that received the highest dose of larvae, exhibited temporary muscular disorders. However, no horse in any group exhibited signs of fever.
• Five horses across the groups showed a significant increase in blood eosinophils, a type of white blood cell typically increased in response to parasitic infections.
• The research noted peak serum levels of lactate dehydrogenase (LDH), aldolase and creatine phosphokinase (CPK) which are enzymes indicating muscle damage, around the 5th week post-infection.
• The presence of specific IgG antibodies, identified and tracked through indirect immunofluorescence and Enzyme-Linked Immunosorbent Assay (ELISA), started appearing between the second and fifth weeks post-infection and disappeared between the 16th and 40th weeks.

Parasite Distribution and Muscle Impact

• Larvae from the parasite were most abundant in the tongue, masseter muscles (jaw muscles), and diaphragm of the infected horses.
• There was a large decrease in the number of larvae in the muscles of horses killed at the beginning and end of the experiment.
• Upon examination of muscular histological sections, larvae were positioned within muscle fibers and were often surrounded by a mild to severe inflammatory response.

Conclusions

• Overall, this study provides crucial insights into how horses respond to varying degrees of Trichinella spiralis infection, including the diverse effects on their bodies and immune responses.
• The findings contribute to the broader understanding of trichinellosis infection in mammals, providing a platform for further research into effective treatment and prevention measures.