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Table 5 Summary of black fly collection and dissection data from catches made at Nachtigal and Essougli

From: Onchocerciasis in the Ntui Health District of Cameroon: epidemiological, entomological and parasitological findings in relation to elimination prospects

 

July

August

September

October

November

December

January

February

March

April

May

June

Nachtigal

 Number of days

3

3

3

3

3

3

3

3

3

3

3

3

 Total black fly catch

3184

1149

6370

11,247

6106

1096

2470

3333

3489

2871

6448

4522

 Number dissected (%)

480 (15.1)

252 (21.9)

372 (5.8)

313 (2.8)

508 (8.3)

265 (24.2)

466 (18.9)

425 (12.8)

379 (10.9)

370(12.9)

276 (4.3)

318 (7.0)

 Number parous (%)a

165 (34.4)

47 (18.7)

38 (10.2)

68 (21.7)

43 (8.5)

13 (4.9)

50 (10.7)

82 (19.3)

77 (20.3)

93 (25.1)

25 (9.1)

40 (12.6)

 Number infected (%)a

1 (0.2)

3 (1.2)

2 (0.2)

0 (0)

4 (0.8)

0 (0)

2 (0.4)

1 (0.2)

1 (0.3)

0 (0)

0 (0)

0 (0)

 Number with L3 (%)a

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

2 (0.4)b

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

 Monthly biting rate

32,901

11,873

63,700

116,219

61,060

11,325

25,523

31,108

36,053

28,710

66,629

45,220

 Monthly transmission potential

0

0

0

0

0

0

1479

0

0

0

0

0

Essougli

 Number of days

3

3

3

3

3

3

3

3

3

3

3

3

 Total black fly catch

1262

993

6160

13,906

2400

1089

947

1114

1325

1504

2127

3066

 Number dissected

399 (31.6)

167 (16.8)

410 (6.7)

321 (2.3)

381 (15.9)

231 (21.2)

215 (22.7)

182 (16.3)

213 (16.1)

331 (22)

312 (14.7)

372 (12.1)

 Number (%) parousa

83 (20.8)

31 (18.6)

54 (13.2)

49 (15.3)

44 (11.5)

20 (8.7)

14 (6.5)

13 (7.1)

48 (22.5)

45 (13.6)

31 (9.9)

40 (10.8)

 Number infected (%)a

2 (0.5)

3 (1.8)

0 (0)

1 (0.3)

2 (0.5)

1 (0.4)

2 (0.9)

0 (0)

1 (0.5)

2 (0.6)

1 (0.3)

0 (0)

 Number (%) with L3a

0 (0)

1 (0.6)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

0 (0)

1 (0.5)

0 (0)

1 (0.3)

0 (0)

 Monthly biting rate

13,041

10,261

61,600

143,695

24,000

11,253

9786

10,397

13,692

15,040

21,979

30,660

 Monthly transmission potential

0

50

0

0

0

0

0

0

58

0

74

0

  1. aCalculations based only on dissected black flies, not on total number of black flies caught
  2. bOf these two infected black flies, one had 4 L3 larvae and the other had 14 L3 larvae (total of 18 L3 larvae in the heads of the two black flies)