Detection of Trichinella infection in slaughter horses by ELISA and western blot analysis.

This research examined the presence of Trichinella infection in horses using two immunoanalysis methods: ELISA and Western Blot. Although the serologic tests found the infection in some cases, their sensitivity was questioned, leading to the proposal of additional detection methods.

Research Methodology

• The study involved the examination of 147 serum samples from horses slaughtered at an abattoir in Mexico.
• Two immunoenzymatic methods, ELISA and Western Blot, were used to check for the presence of specific antibodies that would indicate Trichinella infection.
• The ELISA tests utilized Trichinella spiralis muscle larvae (ML) excretory/secretory (E/S) products, while Western blotting employed molecular ML components corresponding to the TSL-1 antigens.
• These tests were run at various dilutions, ranging from 1:20 to 1:400.

Results

• The ELISA tests found antibodies in 7% of the serum samples at a dilution of 1:400 and in 10% of the samples at lower dilutions (1:20 and 1:40).
• Serum samples from four horses that were known to be naturally infected produced negative results in an ELISA at a 1:400 dilution. At lower dilutions, only two of these four samples tested positive.
• Western blotting showed that serum samples from the experimentally infected horses reacted with ML components of specific weights, which correspond to the TSL-1 antigens.
• Different reactions were observed between serum samples from naturally infected horses and those from the abattoir’s horses in ELISA tests using E/S antigens.

Implications

• The variability of antibodies’ presence detected by the serologic tests indicates that these forms of testing may not offer the required sensitivity for diagnosing horse trichinellosis.
• The researchers suggest additional assays for detection, including the use of ELISA and Dot ELISA or PCR, to identify the parasite antigen and improve the detection of both early and late stages of Trichinella infection.
• This research is particularly important given that direct methods for detecting larvae in horsemeat linked to trichinellosis outbreaks in Europe have proven unreliable.