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[08/03/2005]
 Ivory Coast | |
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Authors:
Dr Francis LOUIS, Yaoundé, Cameroon
Mrs Dominique LOUIS-LUTINIER, Yaoundé, Cameroon.
Acknowledgements:
Dr Christophe Rogier, Le Pharo, Marseille, France
Dr Marie-Claire Henry, Institut Pierre Richet, Bouaké, Ivory
Coast
Dr André Touré, Institut Pasteur, Abidjan, Ivory Coast
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General statistics
Area: 318,000 km²
Population: 17,000,000 (estimate 2002)
Official language: French
Currency: Franc CFA (1 euro = 656
FCFA)
Bordering countries: Liberia, Guinea, Mali,
Burkina Faso, Ghana.
Capital city: Yamoussoukro
Main cities: Abidjan, Bouaké, Man, Daloa,
Korhogo.
Ivory Coast, owing to its geographical position, enjoys a climate
characterised by moderate and stable temperatures, the average of
which ranges between 26°C and 27°C. Atmospheric humidity is in
excess of 70%; rainfall diminishes from south to north and from
west to east.
Schematically, there are two types of climates:
one sub-equatorial climate, south of the 9th parallel, comprising 4
seasons (2 rainy seasons: mid-March to July and October to
November; 2 so-called ‘’dry’’ seasons: December to March and
August-September); the rainfall ranges from 1,500 mm to 2,000 mm
per year.
one humid tropical, so-called ‘’sudano-guinean’’ climate, north of
the 9th parallel, comprising 2 seasons each lasting approximatively
6 months (rainy season from April to October, dry season from
October to April), with a mean annual rainfall ranging from 90 mm
to 1,200 mm.
| Epidemiological facies
In 1982, J-M. Amat-Roze and G. Rémy defined three large
epidemiological zones in Ivory Coast (06):
North of the 9th parallel, the climate features two alternating
contrasted seasons, and malaria is transmitted all year round,
albeit with a sharp increase during the rainy season, from May to
August. The transmission of malaria remains nevertheless high all
year round along rivers (zone I on the map).
South of the 9th parallel, two zones are described:
1.one savannah zone where malarial transmission is endemic and
generalised (zone II on the map) ;
2.one forest zone where malarial transmission occurs only in
clearings (zone III on the map).
I. Seasonal malaria, except along rivers where it is
endemic.
II. Generalised endemic malaria
III. Perennial malaria in forest clearings
In fact, the country exhibits all the malaria epidemiological
facies:
urban malaria in Abidjan and its suburbs: the mean plasmodic index
was 19% in 1988 in asymptomatic schoolchildren in the 5 to 9 age
bracket (15). There are major differences between districts: the
highest transmission level has been noticed at Port-Bouët, with 10
to 30 infectious bites per person per annum (ib/p/a).
lagoon malaria along the coast, east and west of Abidjan. In
children age 0-14, the mean plasmodic index is 15%, the spleen
index is 12.2%, and the ib/p/a rate (entomological inoculation rate
- EIR) is about 288 (62). There is a discrepancy between this
entomological inoculation rate and the plasmodic index
observed.
forest zone malaria in the whole of the south of Ivory Coast, up to
7° in latitude north. The mean plasmodic index is 85% in children
age 0-14, the spleen index is 33% and the mean EIR is 416
(71).
humid wooded savannah malaria: this ecosystem is next to the forest
zone. The mean plasmodic index is 42.2% in children age 0-14, the
spleen index is 22% and the EIR ranges from 0 to 160 (28,
38).
sudano-sahelian or sahelian savannah malaria: this ecosystem covers
the northern part of Ivory Coast. The mean plasmodic index is
11.25% in children age 0-14, the spleen index is 54.6%, and the EIR
ranges from 15 to 240 (62).
| Vectors
Plasmodium falciparum is the predominant parasitic species. The
rates, however, vary as a function of the regions and
studies:
Location | Year | Effective | P.
falciparumprevalence
| Reference | Bouaké Abidjan M’Bengué Bouaflé Abadjin-Doumé M’Pouto Alloukoukro Taï Agou | 1951 1978 1983-1985 1983-1985 1983-1985 1983-1985 1993 1995 1998 | 81 25 ? ? ? ? 228 390 190 | 98.1 52 77.8 82.7 90.7 82.8 100 84 99.48 | 01 02 13 13 13 13 23 71 69 |
Plasmodium malariae is the second plasmodial species diagnosed.
Different studies indicate rates ranging from 0% (Alloukoukro) to
22.2% (M’Bengué).
Plasmodium vivax and Plasmodium ovale remain rather
exceptional.
| Chemo-resistances:
Chloroquine- resistance:
Resistance to chloroquine was first suspected by J-L. Mahoney in
1980 (04). In 1981, he described 3 clinical cases of resistances to
chloroquine (05).
In 1986, B. Soro et al. published 2 cases of in vitro chloroquine
resistance on 33 isolates tested, and recommended the prescription
of chloroquine at doses of 25 mg/kg over 3 days rather than the one
single 10 mg/kg dose administered until then. Unfortunately, this
study was only published in 1989 and was unobserved (11). In 1987,
I. Nicoulet et al. on the one hand, F. Lancastre et al. on the
other hand, observed cases of in vivo chloroquine resistance (08,
10). Since then, the literature reports evidences of resistance to
chloroquinehaving appeared in Ivory Coast in 1987.
M-C . Henry (42) and C. Rogier (62) have elaborated two interesting
syntheses of in vivo studies dealing with the subject (62). We have
completed this corpus with the most recent studies.
Table I – In vivo chloroquine resistance in Ivory Coast, Abidjan
excluded.
Region | Type | Year | Nbr
tested | GE+ at
D7 | %
resistance | RIII | % | Reference | Taï (south-west) | Forest | 1992 1993 | 37 33 | 10 10 | 27 30 | 6 6 | 16 18 | 27 | Adzopé (south-east) | Forest | 1994 1996 | 100 99 | 68 53 | 68 54 | 0 0 | 0 0 | 42 | Man (west) | Forest | 1994 | 105 | 16 | 15 | 8 | 8 | 42 | Tabou (south-west) | Forest Coast | 1993 | 102 67 | 45 40 | 44 60 | 11 11 | 11 16 | 36 | Bonoua (south-east) | Forest | 1992 | 128 | 27 | 21 | 0 | 0 | 42 | Daloa (center-west) | Forest | 1989 | 71 | 6 | 8 | 0 | 0 | NP | Cosrou (south) | Planta tion | 1992 1993 | 24 23 | 3 3 | 13 13 | 0 0 | 0 0 | 27 | Tiéviessou (south) | Planta tion | 1992 1993 1993 | 21 17 82 | 8 8 27 | 38 47 33 | 3 3 5 | 14 18 6 | 27 33 | Bouaflé (center) | Savannah Forest | 1986 | 52 | 0 | 0 | 0 | 0 | 11 | Djébonoua (center) | Savannah | 1992 1993 | 31 29 | 3 3 | 10 10 | 0 0 | 0 0 | 27 | Zouan Hounien
(west) | Forest | 1999 | 51 | 22 | 24 | 5 | 10 | 67 | Man (west) | Forest | 1999 | 102 | 13 | 13 | 1 | 1 | 51 | Agou (south) | Coast | 1997 1998 | 46 | 17 | 37 | 0 | 0 | 69 | Yamoussoukro (center) | Savannah Forest | 1997 2000 | 108 | 29 | 26.9 | 23 | 21 | 75 |
Table II – In vivo chloroquine resistances in Abidjan (and its
districts).
Location | Type | Year | Nbr
tested | GE+ at D7 | %
resistance | RIII | % | reference | Adjamé Abobo Attécoubé Yopougon | Urban | 1988 | 38 | 11 | 29 | 0 | 0 | 14 | Abidjan | Urban | 1988 | 81 | 24 | 30 | 0 | 0 | 15 | Adjamé Yopougon | Urban | 1989 1990 | 112 | 21 | 19 | 0 | 0 | 22 | Abidjan | Urban | 1991 | 106 | 5 | 5 | 0 | 0 | 42 | Adjamé | Urban | 1993 | 49 | 8 | 16 | 0 | 0 | 25 | Abidjan | Urban | 1995 | 46 | 13 | 28 | 0 | |
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