OBSERVATIONS ON THE RELATIONSHIP BETWEEN ASCARIS SUUM BURDENS IN PIGS AND FAECAL EGG COUNTS

Faecal A. suum egg counts were carried out on 69 bacon pigs of which 50 harboured A. suum. Correlation was found to be poor between the egg counts and (1) the total number of Ascaris, (2) the weight of the worms, and (3) the ratio between male and female worms. Only 4 out of 50 Ascaris infected pigs harboured macroscopically detectable juvenile stages of A. suum. It is concluded that the size of A. suum burdens is not to be judged from the number of eggs in the faeces except, perhaps, at very low levels of eggs, i.e. <30 e.p.g. (eggs per g of faeces). Additionally, it is suggested that A. suum burdens are not continuously established once the pigs are infected.