Table 2

Impact of ivermectin distribution on four aspects of onchocerciasis infection and transmission.

River Basin
Intervention Strategy
Impact of ivermectin treatment (Status in 2001)



PH problem eliminated (CMFL= 0)
Prevalence of infection very low (< 10%)
Transmission interrupted (Rx ongoing)
Elimination (control ceased)

Ivermectin only:





- River Gambia focus (A)
6-Monthly ivm.1 since 1989


?

- R. Corubal (B) (up to 1996)
3-Monthly ivm. 1991–1996


?

- R. Corubal (B) (from 1996 onwards)
No ivm. since 1996
?
Increasing prevalence
Transmission ongoing

- Rio Gêba (C)
6-Monthly ivm. since 1989 and no treatment since 1996


?
?
- Falémé (D), Bafing (E), Bakoye (F), Baoulé (G)
Annual ivm. since 1989


?

- Vina Valley (Cameroon)
Annual ivm. since 1987

Prev. mf ≈ 20% in 1999
Transmission ongoing

Ivermectin + vector control:





- Tienfala focus (H)
Annual ivm. since 1987, and (ground) larv.2 since 1994


?

- Bui Gorge focus (I)
Annual ivm. since 1987 (3-monthly from 1994–1996), and larv. from 1975–1996

Prev. mf up to 55% in 1998
?

- Titira and Kouporgou focus (J)
Annual ivm. since 1988, and larv. since 1977

Prev. mf up to 50% in 1998
Transmission ongoing

- Milo and Sankarani (K)
Annual ivm. since 1989, and larv. since 1989




- Asubende focus (L)
Annual ivm. since 1987, and larv. since 1990


Transmission ongoing

- Dienkoa (M)
Annual ivm. since 1988, and larv. since 1975 (with interruptions)




Ivermectin treatment after vector control:





- Bougouriba (N)
4-Monthly ivm. since 1996, and larv. from 1975–1990


Transmission ongoing


1ivm.: ivermectin treatment 2larv.: larviciding

Borsboom et al. Filaria Journal 2003 2:8   doi:10.1186/1475-2883-2-8