In vitro development of Ancylostoma tubaeforme, Ancylostoma caninum and Toxocara cati

Although no research has been reported on in vitro cultivation of Ancylo s toma tubae forme or Toxoc ara cati , partially successful attempts to grow other hookworms and ascarids through various segments of the life-cycle have been reported.In a single experiment, Weinstein (1954) reported development of eggs of Necator americanus to the filariform stage (67% yield) in 50% chick embryo extract (CEE) ; these were normal morphologically, but small in size.When CEE was supplemented with formaldehyde killed Escherichia coli , 98%developedto the filariform stage and were normal in size.Fifty per cent CEE, when diluted with beef heart infusion broth (1 part CEE: 2 parts broth), resulted in higher yields of filari- form larvae than CEE alone.Even when diluted 1:8, a yield of 59% filariform larvae was obtained.Broth alone would not support growth.Using the same medium in which Nippostrongylus muris was success- fully grown, Weinstein and Jones (1959) inoculated cultures with third- stage larvae of Necator americanus .Several worms developed a pro- visional buccal capsule, and a few reached the fourth stage.One fourth-stage female reached 1.7 mm in length and sbowed early differ- entiation of the genital tract.McCoy (1930) grew Ancylostoma caninum eggs to infective stage on ordinary bacteriological agar inoculated with Bacillus coli (syn.Esch erichia c oli ) .The worms attained most rapid development at 37 C, and reached infective stage in 48 hours.Weinstein (1949, 1953) reported growing Ancylostoma caninum from the egg to the filariform larva stage in the absence of living bacteria