A comparison of post-mortem analysis of helminths with faecal egg counts

Intestinal helminth infections are very common amongst residents of the Colombo area. Most common by post-mortem examination of 104 cases of sudden death were Trichuris trichiura (97.1%), Necator americanus (88.5%), Enterobius vermicularis (77.9%) and Ascaris lumbricoides (40.4%). Trematode and cestode infections were not encountered except a single case of H. diminuta infection. A comparison of the results obtained by the direct smear method for examining stools missed cases harbouring gravid females of up to 3 Ascaris lumbricoides, 29 Trichuris trichiura and 66 Necator americanus. The direct smear revealed all the helminths present except threadworms in only 30% of the cases. The correlation between worm loads calculated from ova counts and actual numbers harboured was fairly close in 19 out of 35 cases for Ascaris and 37 out of 78 cases for Necator americanus. Highly erroneous results were obtained in many instances when worm loads were calculated from the results of ova counts.