Assessment of cercarial rhythmicicity and dynamics as micro-epidemiology factors influencing transmission pressure of schistosomiasis in Gunaid Scheme, Sudan

الملخص EN

For understanding the dynamics of schistosoniasis transmission in any endemic area, elements of analytical micro-epidemiological aspects should be highlighted.

The key factors of these aspects are the production and dynamics of the infective stage, the most risky time for man to acquire infection.

Within the aforesaid frame, a series of laboratory experiments were conducted to determine cer-cariai productivity and dynamics from Biomphalaria pfeifferi snails infected with different numbers of Schistosoma mansoni miracidia.

The laboratory experiments indicated that snails exposed to 4-6 miracidia survive longer and produced more cercariae.

The peak of s.

mansoni cercarial production coincides with the peak of human ac-tivities during the day.

Therefore, those who contact watercourses in the field during the day, or late in the after noon, will be at a greater risk of becoming heavily infected if water is stagnant.

The reflection of the cercarial emission rhythms on the micro-evolutionary changes taking place in schistosome populations, was highlight.

The finding could pronouncedly be exploited in a well-planned organised health education programme, for villagers to a void watercourses during mid day.