OCP/EACl4/Briefing

ONCHOCERCIASIS CONTROL PROGRAMME

IN

WEST AFRICA

Expert Advisory Committee Fourteenth session

Ouaeadoueou.

7-ll

June 1993

Briefing

session, 5 June I993

OCP/EACl4/Briefing

paper no 6

ORIGINAL:

FRENCH

ENTOMOLOGICAL ACTIVITIES OF

NATIONAL

TEAMS

IN

WESTERN ZONE

l.

Operational structures and ^personnel

In 1993 the entomological network in Western Zone remains the same as

in

1992 with three sectors (two in _Guinea, one in Sierra Leone), l2 operational bases (nine in Guinea, three in Sierra Leone) and 35 capture/dissection teams covering ⁷⁸ capture points.

A

total

of

²⁴⁸ national staff are involved

in

entomological, hydrological and administration activities

in

Guinea and Sierra Leone. The capture/dissection circuits have been reduced following the suspension of larviciding

in

Southern Sierra Leone and entomological surveillance on the Makona

in

guinea.

2.

^Training

in

1992

a)

^Trainine at OCP Bamako

- ²

technicians

from

Sierra leone national ONCHO team have been trained

for four

months on cytological identification

of

S. damnosum s.l. larvae

-

2 technicians from Guinea national ONCHO team have been trained

for

two months on morphological and morphometrical technics

of

identification

of

adult Similium flies.

b)

In-service trainine

-

²⁴ technicians from Guinea and l2 technicians from Sierra Leone were trained at their operational bases on morphological identification

of

adult Simulium flies.

3.

Entomological results

The annual transmission potentials (ATP) _{due to savanna} flies from

April

1992 to March 1993 shown in annex la indicate that in the Western Zone, only

four

points over I

l8

(30/o) visited have ATP slighly above the treshold

of

^100. These good results confirm:

a)

ⁱⁿ

^initial

zone, the success of vector control activities shown by the significant decrease of transmission even at the former reinvasion sites on the Baoule and Bagoe Rivers in Mali where high densities

of

flies were noted;

b) in

Guinea, the success

of

combined larviciding and ivermectin treatment

OCP/EACl4/Briefing

^{paper no} 6 Page 2

In nothern Sierra Leone, excellent results were obtained (no transmission by savanna flies were recorded) despite the long suspension

of larviciding

due

to

the rebel incursion

from l4

December 1992 to 27 March I993. In the south of Sierra leone, the high transmission recorded are due to forest flies namely S. leonense, S. yahense

and

S. squamosurn species ^(see annex

lb).

4. Identification of

the parasites

with

DNA probe

The identifications of the

^parasites

with DNA probe

have revealed

an

important proportion

of

animal onchocerca or else wich _allowed us to adjust the ATP obtained on various

river

basins. The identifications results are listed in annex 2

for

reference.

5.

Impact

of

ivermectin treatment on transmission

In

Guinea-Bissau studies on the impact

of

ivermectin treatment (three times/year) on transmission

from

November 1990

to

December 1992 showed a decrease

of

about 400/o

in

the intensity

of

transmission

in

Rio Corubal (annex 3).

A

sub-committee led

by Dr

Laurence Osei, consultant, met

in

Ouaga

in

March 1993 to look

into

the possibility to continue these studies

in

other zones where solid base

line

data are available.

It

was proposed to ^gather information on:

-

Gambia River at Mako, where ivermectin treatment has been done twice a year, for five years;

-

^{The Bakoye} at pont Toukoto and Seourou where twice-a-year ivermectin treatment should be initiated;

-

an area where ivermectin treatment is done once a ^year

The sub-Conrmittee

will

submit its proposals at the briefing session

of

^EACI4

6 Post- treatmen

t

studies

6.1.

^Banifine

^IV

After cessation of larviciding in January 1992 post-treatment studies showed an

infectivity

level of 0.39 infectious females/1000 parous flies. Due to the very low number

of

the flies (7 670 parous flies, caught) the studies

will

be planned again

in

1993.

6.2.

Bandama blanc

Post-treatment studies organized at Badikaha from January to June

l99l

and from January to September 1992 showed an

infectivity

level

of

1.08 female

with

L3

in

head/1000 parous flies on a total

of

20 335 parous flies dissected. This result confirm that the situation is satisfactory.

6

_o\

il

a

g a

N

o\

E g

g

4,

r-.1

E{

EIE]

o

Ar

z o

(nH

ao

IJ

?h

a

H

6 _o

o

E,

=

I

N o

J

E,

lrl z

* a

lrl o a

z o o a

=

^cn

z

E,

t- t! o 3 lrl

f z.

z

(t,

UJ

tr

z

lr,

l- o

o-

oCP/EAC14/Briefing paper

no. ⁶

Page 1)

Cr

\t

t'.

^I

ot/) I

t

i

( \

(

\ t

._.,9.

t

'.'ar;o

l t!

oc Eo

o o

.=

E

-e

cd,

zo

-9 co E

@

=o

E'E

!t oc oc No

ilrj Ed dz

Fl:-

z-

b*.r

JF

o(L

o

o

JE

b _o 3 o z

(n

o

UJ

z

o

_H

a a

H H

E

E<

tr]

a 3

_) t .1

I 3

.4

I

( t

o

I

F (,J

lru.

,,'J'

\ o

\ ₍

^{^-(-}

o

a

n

_o

q

,

)

l-

q

(

)

\

\ '.L

'l

,i;'$'2

)'r

I

.-L

i)

'6^'

LU

tl l)

G

E

<\

=N m

\

\

a -)

oI

Y

UU z.

-

\)

?

r'

ⁱ

l'

\o

/1 ')+.

')

,l't

.'.iu{

o

UJ

J Z

t

)

I

5 ^ I

E

:

:t

il T

t t

.\\-, ..:

_IT

lr o

o

o|

Io 33

\t

A\

oo

vrt

sfl

ei

_VYN

⁸ CEC

,\.

l) -

\'

lr''

Ai'

\^\,

(-

r{

d

&:t

H

e

rld HH

i

(

I

I

)

O U

-}\

.t

E q)

'l

, t-,--C

(

q

I

U

t

I

0CP/EAC14/Briefing paper

no, ⁶ Page 4

IJ o

z o

ct CI'

=

U'

z

G,

F ul o

J a

lr, :f

z z

o J

Lr,l

tr z

lr!

F

o

o-

EDc E9

;

o_o

.=

E

€a,

c

z

o

I

co Eo '6

o

I

E oc oc No

#5 E<

<F c= z

H ITJ

fl6 5N

(Lo o

o

JE

a=()

I

o z 9

lrJ

F

x

UJ

a o

H

TT2

a

H H

B

E

H

a

trl

=

U

: )

.)

o

o|

83 to

st

A\

oo oB oS ?

ei _VYN ⁸

ooo

p

r'l frl

H

a

4

p

H

a \)

^N/,

)

C'U

@

!

t

o

<r) TL

d)

)

U)o

,a--@

U

(oh

,,o

tn ,t

,(1

AI

.3o

I

I

).

)

6o G

i-, t

ts

\

:i;'{'2

,.-9

)i

.(

(

i;

.4

r"

I (

.,t

a

\

U

trJ

r9

-

rf -\\, 7, ^I

.ir _-

e

llnl,r i

I

1+'i

(>

I

(

_U

i\.

,J

a _\

\-

t_

I

-(

)

AI.INEXE 2/ANNEX 2

Resultats des identifications de parasites par sondes a

enN

Results

of

identifications

of

^parasites

with DNA

probe

OCP/EACl4/Briefing

^paper nP 6

Page

⁵

4/5

de non O. volwlus,

4/5

de non O. volwlus,

4/6

d,e non O. volwlus,

4/5

de

non

O. volwlus,

MALI

Baou16

Niger Bagoe

COTE-D'IVOIRE

Bandama B.

Marahoue

Sassandra

SIERRA LEONE

Koloni

N'Zana

Madina-Diassa

Faya Metela

Marabadiassa Naramou Badikaha

Kato Zuenoula Kongasso Yapleu Massadougou Niamotou

Mano Mokassi Gbaima

l/5

O. volwlus,

l/5

O. volwlus,

l/6

O. volwlus, 116 O. ochengi

l/5

O. volwlus,

I

/l

^{O. ochengi}

4/4

O. volwlus de savane/Savanna species 2

Ll

L2 O. volvulus de savane/Savanna 23/24 O. volvulus de savane/Savanna

I

/24

^{O. ochengi}

2/2

O. volvulus de savane/Savanna

I

/l

O. volvulus de for0t/Forest 3/3 O. volvulus de savane/Savanna

|

/l

O. volvulus de for6t/Forest 2

Ll

O. volvulus de savane/Savanna

I /

I

O. volwlus de savane/Savanna

7

/7

^{O. ochengi}

|

/l

O. volvulus de savane/Savanna

l/l

Non O. volvulus

?

: ^Q6Cuqtion de ltintensit6 de la t T\ .'Reduction of intensity of

.El I S S aU/curlrEA-BrESAu Zone Initi 1s

r,:.usmission transmlssr-on

l,-1 t 2

LrUlnee

(Cade, Cabuca et Cheche )

^:

407o

(D agnangofo, ^&rea Vialadougou, Kongasso

et Ngolodougou)

^:

flies

t

de r6duction du ^{5 8 Vo}

nombre de'L3 tOte ^{de r6duction} du nombre pour 1 ooo pares ^de L3 tote pour I ^ooo

/4G'6 reauction of ^r'J rreaa/t.oo parous flies

f58/o ^reauction "P?ff:a/rooo ^perous

oe/arct4/

Briefing paper

no.

⁵

Pa6e 6

emwr(B) f

I 988 I 1989 t99t I 1992

(avalrt

trailcrnent)

^{(2/3 ans} apris

before treatment

. traitement)

I v e rm ecfiilLtEiriier

^{tue atunent}

IY]IO,ETTN _ALO]M

t978179 1982 e 1984

(avant

traitenrent)

(3/4 ans aprds

be&catreatnent -,-traitentettt)^.

^.b

Larvi cidad SElitUc

trea b'

I"ARECIDES

ATONE

'