Development and evaluation of an egg hatching technique for diagnosis of schistosomiasis mansoni

ABSTRACT

The modified quantitative Kato-Katz fecal smears are considered by the WHO as the golden technique for diagnosing intestinal schistosomiasis. The sensitivity of the Kato-Katz smears decreases when tile intensity of infection is low. Some modified hatching techniques when compared with the Kato-Katz thick smears revealed a higher sensitivity. The present work aims at developing and evaluating an egg hatching test to be used for diagnosis of schistosomiasis mansoni under field conditions. Stool samples were collected from 284 human cases from five different Egyptian governorates. Only samples confirmed positive for S. mansoni infection in our laboratory by the Kato-Katz fecal thick smears or the modified hatching technique were considered positive and used in the present work. A portion of each stool sample was examined by three Kato-Katz thick smears. Another portion [3 gm] was examined by the developed hatching technique. Diagnosis based on three Kato-Katz thick smears revealed a sensitivity of 94.7%. The hatching technique detected 85.2% of the cases during the first day examination, but after two days examination it detected all tile cases, i.e. 100% sensitivity. Results showed that the highest daily sensitivity of the hatching technique was during the first day [85.2%], followed by a gradual decrease of the daily sensitivity to 65.8% in the second, 14.4% in the third, and zero in the fourth and fifth days. Diagnosis based on the hatching technique used in the present study is significantly more sensitive than three Kato-Katz thick smears. The modified hatching technique is simple and can be easily used under field conditions