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Table 4 Transmission by Pulex irritans using rat blood and subsequently fed sterile rat blood every 2 to 3 days (group IV)

From: Poor vector competence of the human flea, Pulex irritans, to transmit Yersinia pestis

Day post-infection

Total fleas

Fed flea number

Infection rate (%)

Mean CFU/flea

Blocked (B) fleas

Partially blocked (PB) fleas

B + PB fleas (%)

Total CFU transmitted

CFU transmitted per fed flea

Exp #1 (owl; Fig. 4A)

        

 0

ND

54

100

4.9 × 103

 3

29

25

ND

ND

0

0

0

0

0

 6

21

19

ND

ND

0

4

21

0

0

 8

17

13

ND

ND

1

3

31

59

4.5

 10

8

7

50

2.9 × 106

0

0

0

0

0

Exp #2 (owl; Fig. 4B)

       

 0

ND

57

100

6.1 × 104

 3

36

36

ND

ND

0

4

11

23

0.6

 6

19

19

ND

ND

0

0

0

107

5.6

 8

11

11

89

ND

3

4

64

306

28

 10

4

4

100

4.2 × 106

0

1

25

97

24

Exp #3 (fox; Fig. 4C)

        

 0

ND

108

100

2.1 × 104

 3

97

90

100

3.3 × 106

0

1

1

81

0.9

 5

94

30

92

1.9 × 106

0

7

23

0

0

 7

55

43

90

2.3 × 106

0

0

0

0

0

 9

30

26

ND

ND

4

1

19

7

0.3

 11

20

14

ND

ND

1

0

7

4

0.3

 13

11

6

58

3.4 × 105

0

0

0

0

0

Exp #4 (fox; Fig. 4D)

         

 0

ND

111

100

5.3 × 103

 2

101

78

88

1.9 × 106

0

0

0

3

0.04

 4

73

61

ND

ND

0

0

0

ND

ND

 6

48

41

ND

ND

1

0

2

25

0.6

 8

39

32

ND

ND

1

1

3

27

0.8

 10

22

15

ND

ND

1

0

7

0

0

 12

10

6

58

2.9 × 106

0

0

0

0

0

Exp #5 (fox; Fig. 4E)

       

 0

ND

124

88

3.7 × 103

 2

117

94

ND

ND

0

0

0

0

0

 4

74

58

20

5.4 × 105

0

0

0

0

0

 6

63

53

ND

ND

0

0

0

0

0

 8

45

35

ND

ND

0

0

0

0

0

 10

42

22

ND

ND

0

1

5

2

0.1

 12

37

25

ND

ND

0

0

0

0

0

 14

49

22

ND

ND

0

0

0

0

0

 16

53

47

ND

ND

0

0

0

0

0

 18

45

15

ND

ND

0

0

0

0

0

 20

44

36

ND

ND

0

0

0

0

0

 22

38

9

ND

ND

0

0

0

0

0

 24

36

35

ND

ND

0

0

0

0

0

 26

35

30

0

0

0

0

0

0

0

  1. ND not determined. The source of the fleas used for the experiments (owl or fox) is indicated