| susceptibility of three successive snail generations from positive and negative laboratory bred biomphalaria alexandrina from different localities in egypt to infection with schistosoma mansoni from giza. | susceptibility of snail vectors to schistosome infection varies between geographical areas, populations in the same area and among individuals in the same population. it is also affected by biological factors of which are snail size (age), number and age of miracidia exposed to water, temperature, illumination and darkness. our preview studies indicated that snails 4-6 mm in diameter exposed to 5 freshly hatched miracidia under light and in water at 25 degrees c are optimum conditions for infect ... | 1997 | 9257970 |