Establishment of Ascaris suum in the pig: development of immunity following a single primary infection.
Development of immunity after a single primary infection of Ascaris suum in pigs was investigated with regard to the worm population dynamics of a superimposed A. suum infection, host immune response and gross liver pathological changes. Group A was given a primary infection of 60,000 infective A. suum eggs and group B was left uninfected. Four weeks later both groups A and B were inoculated with 1,000 A. suum eggs, and subgroups were slaughtered 7, 14 and 21 days post challenge infection (p.c.i.). An uninfected control group C was slaughtered on day 21 p.c.i. The challenge worm recovery in group A was reduced compared to group B by 12%, 50% and 75% on day 7, 14 and 21 days p.c.i., respectively. In both groups was the expulsion of worms initiated between day 14 and 21 p.c.i. However, in group A the worms were recovered more posteriorly in the small intestine and 21 days p.c.i. the mean worm length was significantly shorter than in group B (p = 0.01). The results above were associated with significantly higher (p < 0.05) antibody response and higher eosinophil counts in group A compared to group B. The present results suggest that the larval growth and survival of a challenge infection are decreased, probably due to higher antibody and eosinophil attack during the migratory phase.
Helwigh
A B
AB
Danish Centre for Experimental Parasitology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark. abh@kvl.dk
Nansen
P
P
D000704:Analysis of Variance; D000818:Animals; D000909:Antibodies, Helminth / Q000302:isolation & purification*; D001196:Ascariasis / Q000276:immunology / Q000662:veterinary*; D017165:Ascaris suum / Q000276:immunology* / Q000302:isolation & purification; D007422:Intestines / Q000469:parasitology; D008099:Liver / Q000473:pathology; D008297:Male; D010270:Parasite Egg Count; D013552:Swine; D013553:Swine Diseases / Q000276:immunology*
D000909:Antibodies, Helminth