Fig. 154.—Cestodes and cestode ova.
Ova in Faeces.—It is in the faeces we examine either for the parasites or for their ova in connection with practically all the flukes, except the lung fluke and the bladder fluke; for intestinal taeniases and for practically all the round-worms, except the filarial ones.
In the tropics, the examination of the faeces exceeds in value that of urine and is possibly more important than blood examinations.
Helminthiasis Statistics.—There is one point in connection with the statistical reports as to the presence of intestinal parasites in a given section of the tropics that I desire to emphasize.
Because a limited district shows a certain prevalence of intestinal parasites we should not conclude that the entire country from which such findings emanate shows a similar extent and type of infection. Take for instance the Philippine Islands.
Fig. 155.—Trematode ova.
In 1910, there were made in Cavite Province 932 stool examinations upon specimens from cases of sick people and of these only such patients as it was thought required such an examination for diagnostic reasons were made to bring such a specimen of faeces.
Of the 932 examinations, 135 or 14.4% failed to show the presence of intestinal parasites or their ova. The remaining positive examinations gave findings as follows:
| Organism | Number of infections | Per cent. |
| Ascaris | 627 | 67.2 |
| Trichocephalus | 607 | 65.1 |
| Flagellates | 135 | 14.4 |
| Amoebae | 111 | 10.9 |
| Hookworm | 23 | 2.4 |
| Taenia saginata | 3 | 0.3 |
| Balantidium | 1 | 0.1 |
| Strongyloides | 1 | 0.1 |