Infection caused by the trematode
Echinostoma paraensei
has been shown to interfere in the natural resistance to
infection by
Schistosoma mansoni
.
Biomphalaria glabrata
is susceptible to infection, while Taim isolate
Biomphalaria tenagophila
is resistant to infection by
S. mansoni. These two snail species were assessed for infection with
E.
paraensei two days after exposure to
S. mansoni miracidia. The number of
B. tenagophila and
B. glabrata infected
with
E. paraensei was lower in co-infected group, suggesting an antagonistic relationship.
B. glabrata showed an
increase in its susceptibility to
S. mansoni, whereas
B. tenagophila maintained its refractoriness to
S. mansoni
infection. Weekly comparisons made between the
E. paraensei cercariae released from
B. tenagophila and
B. glabrata
mono-infected snails revealed no quantitative differences. In contrast,
S. mansoni cercariae released were higher in
the
B. glabrata co-infected group. Mortality rates were significantly greater in both species pertaining to co-infected
group and unexpected mortalities were also observed in
B. tenagophila exposed only to
S. mansoni miracidia. Our
study revealed that the
B. tenagophila Taim isolate is susceptible to
E. paraensei infection, although infection did not
alter its resistance to
S. mansoni infection.
