Table 1 Mean survival time for snails exposed to different homologous or heterologous doses of S. mansoni during 25 weeks of follow-up

Mwea B. pfeifferi x Mwea S. mansoni

  1 miracidium

7.66

0.80

6.09

9.23

  5 miracidia

6.18

0.80

4.61

7.75

  10 miracidia

4.04

0.43

3.20

4.88

  25 miracidia

4.14

0.55

3.05

5.23

  Overall

5.51

0.35

4.83

6.18

Mwea B. pfeifferi x Asao S. mansoni

  1 miracidium

5.10

0.58

3.96

6.24

  5 miracidia

5.34

0.38

4.59

6.09

  10 miracidia

3.94

0.26

3.43

4.45

  25 miracidia

4.40

0.37

3.68

5.12

  Overall

4.70

0.21

4.28

5.11

Asao B. pfeifferi x Mwea S. mansoni

  1 miracidium

14.42

1.34

11.80

17.04

  5 miracidia

13.52

0.88

11.80

15.24

  10 miracidia

12.44

1.18

10.13

14.75

  25 miracidia

10.30

0.69

8.95

11.65

  Overall

12.68

0.54

11.63

13.73

Asao B. pfeifferi x Asao S. mansoni

  1 miracidium

12.70

1.35

10.05

15.35

  5 miracidia

14.18

1.26

11.71

16.65

  10 miracidia

9.62

1.25

7.17

12.07

  25 miracidia

10.98

1.49

8.06

13.90

  Overall

12.06

0.70

10.68

13.44

Overall analysis

  Negative control

18.34

0.86

16.65

20.03

  1 miracidium

9.97

0.60

8.80

11.14

  5 miracidium

9.81

0.53

8.78

10.84

  10 miracidia

7.51

0.52

6.50

8.52

  25 miracidia

7.46

0.50

6.48

8.43