Abstract:
This study aimed to determine the sensitivity and efficiency of various
techniques that are used for the diagnosis of intestinal and urinary
schistosomiasis and aimed to compare the results obtained by these techniques
with the routine wet preparation method. The rate of prevalence concerned with
age and sex were comparable for the different methods.
The study determined the levels of infection by S.mansoni in New Halfa
scheme and S.haematobium in three different areas in Khartoum North during
the period from January to April 2009. The study included 400 specimens (200
stool samples for S.mansoni and 200 urine samples for S.haematobium). The
overall prevalence of S.mansoni in New Halfa scheme was found to be 74%,
and more frequent among the school children at the age group < 15years
(87.7%).
The overall prevalence in Khartoum North was found to be 46% and the
highest rate was found in Tibet Alahamda (61%) and more seen in school
children (48.5%).
Amongst the diagnostic methods used for stool examination, the formal
ether concentration technique proved to be the most sensitive method (74%) for
detection of infection and to determine the mean egg count, followed by the
modified Kato-Katz technique (68.5%) which gave results relatively similar to
that obtained by the formal ether concentration technique. Both methods are
suitable for field work. Other methods showed variably less sensitivity and
quantitative efficiency. The study recommended that wet preparation is not
suitable for detection of mild and chronic infections.
For the diagnosis of S.haematobium, the sedimentation and filtration
techniques showed the same sensitivity (46%) but the filtration technique
sometimes gave false positive results due to improper washing of filters. The
hatching viability test gave weak results which attributed to immunity and to
the fact that most of the children subjected to treatment during the past few
months. So, this test can be used to assess the of the treatment and to determine
the effective dose. Efficiency showed less sensitivity and can be used in
qualitative diagnosis and to determine the effectiveness of treatment.
