Abstract
Ascaris suum eggs were collected from pig faeces or dissected from worms obtained from the same pigs. Eggs from the two sources were allowed to embryonate in 0.1 N H2SO4, in 1 % buffered formalin or in tap water. The embryonation of the sulphuric acid and water cultures occurred at the same speed, while the formalin cultures developed slightly more slowly. By experimental inoculation of helminthfree pigs and subsequent counting of white spots in the livers and larvae in the lungs day 7 p. i., the infectivity of eggs dissected from worm uteri and embryonated in sulphuric acid (a normal laboratory procedure) was compared with that of eggs collected from faeces and embryonated in water (i.e. more naturally developed eggs). The results suggest that the two types of eggs were equally infective. For this reason the common practice of using Ascaris eggs dissected from worms for experimental infections might be acceptable.
Keywords: egg culture, white spots, larvae, lungs, baermannization
Sammendrag
Ascaris suum ägg samlades från svinträck samt dissekerades från honmasker från samma svin. Ägg från bägge källor fick embryonera i 0.1 Ν H2SO4, i 1 % formalin samt i vatten. Formalinkulturen utvecklades litet långsammare än de andra kulturena. Infektiviteten av ägg som isolerats från maskuteri och embryonerats i svavelsyra jämfördes med ägg från träck som embryonerats i vatten. Med båda kulturena inokulerades en grupp av tio ungsvin, som slaktades 7 dagar senare. Larver räknades från lungorna och “white spots” från levrarna. Resultaten indikerar att de bägge typene av ägg var lika infektiva. På denna grund kan man för infektionsförsök rekommendera användandet av ägg dissekerade från maskar.
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