Sylvatic and domestic Trichinella spp. in wild boars; Infectivity, muscle larvae distribution, and antibody response

Thirty-six wild boars were inoculated with Trichinella spiralis, Trichinell a nativa. Trichinella britovi, Trichinella pseudospiralis (USSR). T. pseudo spiralis (USA). T. pseudospiralis (AUST), Trichinella murrelli, Trichinella T6, and Trichinella nelsoni. The wild boars were killed at 5 and 10 wk pos tinoculation (PI). and the number of muscle larvae per g (Ipg) of tissue wa s determined for 18 muscles or muscle groups. Five weeks PI. all Trichinell a genotypes had established as muscle larvae, but their infectivity varied widely: T. spiralis established in high numbers (mean = 296 lpg) T. britovi , T. nelsoni, and 1 of the T. pseudospiralis genotypes (AUST) in moderate n umbers (mean = 53-74 Ipg). whereas the remaining genotypes were poorly infe ctive (mean = 2-16 Ipg). Because of considerable weight gain of the wild bo ars, an estimated total larval burden (live weight x Ipg) was calculated fo r each animal. The total larval burden did nor change significantly over ti me for T. spiralis. T. murrelli. T. britovi. T. nelsoni. and T. pseudospira lis (USA and USSR), whereas a significant reduction could be demonstrated f or T. nativa, Trichinella T6, and T. pseudospiralis (AUST). Diaphragm and t ongue were predilection sites in wild boars, independent of Trichinella gen otype and infection level. At low infection levels, a greater percentage of larvae were found in diaphragm and tongue at 10 wk than 5 wk PI. Antibody responses increased rapidly between weeks 3 and 5 PI, For T. spiralis and T . nelsoni. the high antibody level persisted throughout the experimental pe riod, but for T. nativa. T. britovi, T. murrelli, or Trichinella T6, the le vels declined. For T, pseudospiralis, the antibody response increased more gradually between weeks 3 to 10 PI. Infection with all genotypes of Trichin ella were detected using any of 7 excretory-secretory antigens. which point s to the potential use of I common antigen for epidemiological studies on T richinella in wild boars. In conclusion, T. spiralis is highly infective to wild boars. T. britovi. T nelsoni. T pseudspiralis (USA), and T. pseudospi ralis (USSR) are moderately infective. and T. nativa, T. murrelli. T. pseud ospiralis (AUST), and Trichinella T6 are poorly adapted to this host specie s.