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[08/05/2005]
 Benin | |
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Dr Francis Louis, IMTSSA, Marseille
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General Facts
Area: 114,763 km²
Population: 5,766,000 inhabitants (estimated
for 1997)
Capital: Porto-Novo (1,200,000
inhabitants)
Currency: CFA
franc
Official Language: French
Bordering countries: Nigeria, Niger, Burkina
Faso, Togo 
Out of 192 countries, Benin ranks
174th for life expectancy, 156th
for infant mortality, 160th for GNP per capita,
116th for daily calorie intake,
192nd for literacy, 149th for
the percentage of children in full-time education (source : Atlas
Encyclopédique Mondial, Nathan Ed., Paris 1996,
pp.118-119). Average monthly rainfall (in mm) is shown in table I:
Month | jan | fév | mars | avril | mai | juin | juil | août | sept | oct | nov | déc | | Coast | 20 | 40 | 50 | 100 | 260 | 550 | 110 | 20 | 200 | 130 | 90 | 50 | | North | 20 | 20 | 50 | 50 | 200 | 350 | 80 | 20 | 30 | 120 | 30 | 20 |
Generally speaking, there are 3 climatic
zones: On the Coast: A
tropical humid climate with 2 rainy seasons (April - July
and September-November) and 2 relatively dry seasons
(August and December March); The center (Abomey
region), a zone similar in climate to Guinea –Sudan and
characterized by a tropical semi-humid climate. The North is a
semi-desert region with a dry season from September to May, and a
rainy season from June to August. Rainfall varies from 400 mm to
800 mm and the temperatures vary from 24°C to 38°C. Cotonou presents
its own particular situation (cf vectors). | Epidemiological facies
Plasmodium falciparum is by far the most dominant
parasite (97.1%). Plasmodium malariae represents
the remaining 2.9% (21).
Malaria is the leading cause of morbidity in Benin: its average
incidence rate is at 65.8 p.1000 and represents more
than 30% of grounds for outpatient consultations (24).
Malaria in Benin is traditionally considered as having two major
epidemiological settings: in the south, Malaria spreads along the
lagoon shores, with a continual and intense transmission, the
principal vector being Anopheles melas and less
frequently Anopheles
gambiae; In the north there is intermittent seasonal
transmission of a tropical setting type (MOUCHET J. et al. -
Typologie du paludisme en Afrique. Cahiers Santé 1993 ; 3 :
220-238), where the vector is Anopheles gambiae.
| Vectors
The two main vectors are Anopheles gambiae, present
across the country and Anopheles melas,
widely present along the coast. According to M. Akogbeto and Coll,
in Cotonou, "the density of the vector Anopheles gambiae s.l.
varies according to the degree of
urbanization of the area. The average number of yearly bites is
1179 in the town center, 3666 in the town outskirts and 3363 in the
intermediary zones. The average sporozoitic factor is at 7.1%. In
the town center, transmission is seasonal and lasts 3 months,
during which time each person will receive about 33 infectious
bites. The maximum sporozoitic factor observed is 12%, with a daily
inoculation rate of 1.02. In the belt-way around the town,
transmission is also seasonal but lasts 8 months during which each
person will receive about 58 infectious mosquito bites. Contrary to
other inter-tropical continental African towns, the intensity of
the transmission in Cotonou is very high: 46 infectious bites per
person per year (16).
In lagoon areas, Anopheles melas represents
88 % of anopheles and Anopheles gambiae s.s. the
remaining 12%. The two species coexist with notable fluctuations
according to the season (in the low season for example the
desalinization of the water is favorable to Anopheles gambiae)
Jacques Brunhes and Coll.(Les anophèles de la région
afro-tropicale, logiciel ORSTOM Ed., 1998) compiled a list of 22
species of different anopheles in the countries : Anopheles arabiensis, Anopheles
brohieri, Anopheles brunnipes, Anopheles domicola, Anopheles
flavicosta, Anopheles funestus, Anopheles gambiae, Anopheles
hargreavesi, Anopheles leesoni, Anopheles maculipalpis, Anopheles
melas, Anopheles nili, Anopheles obscurus, Anopheles paludis,
Anopheles pharoensis, Anopheles pretoriensis, Anopheles
rhodesiensis rhodesiensis, Anopheles rivulorum, Anopheles rufipes
rufipes, Anopheles squanosus, Anopheles wellcomei wellcomei and
Anopheles ziemanni.
| Chemoresistance
1. Resistance to chloroquine: In 1986, Jacques LE BRAS recorded the first 6 cases
of Plasmodium falciparum resistance
to chloroquine, occurring in patients undergoing weekly
chemoprophylaxis (3). Mr. Rosenheim and Coll. noted 5 other cases
the same year, in patients undergoing daily chemoprophylaxis (4).
Ten of the eleven patients came from the Cotonou region. In 1987,
Martin DANIS and Coll. recorded 8 cases observed in the
Pitié-Salpêtrière hoital (5). Following this,
many studies were published, for the most part based upon in vivo
tests (table II) in three zones: Cotonou and Porto-Novo on the
coast, the province of Zou, directly north of Abomey, and the two
provinces to the north of the country in Parakou, Malanville,
Djougou and Natitingou.
Table II – In vivo chloroquine-resistance in Benin
Year | Area
Studied |
Numbers
tested |
Number of
resistants | Percentage | Reference | | 1982 | Cotonou | 64 | 0 | 0 | 9 | | 1984 | Cotonou | 51 | 0 | 0 | 9 | | 1987 | Cotonou | 65 | 34 | 53 | 14 | | 1987 | Zou | 42 | 34 | 80,9 | 9 | | 1987 | Cotonou | 72 | 7 | 9,7 | 6 | | 1988 | Cotonou | 46 | 10 | 21,7 | 9 | | 1989 | Porto-Novo | 40 | 27 | 67,5 | 9 | | 1989 | Porto-Novo | 48 | 25 | 52,1 | 9 | | 1992 | Parakou | 71 | 22 | 30,9 | 27 | | 1992 | Malanville | 75 | 18 | 24 | 27 | | 1993 | Djougou | 72 | 4 | 5,5 | 27 | | 1993 | Natitingou | 80 | 2 | 2,5 | 27 |
There are less published in vitro studies (Table III).
Table III – In vitro Chloroquine-resistance in Bénin
Year | Area
Studied |
Numbers
tested |
Number of
resistants | Percentage | Reference | | 1987 | Cotonou | 36 | 21 | 58 | 9 | | 1987 | Cotonou | 41 | 19 | 46 | 7 | | 1987 | Zou | 18 | 3 | 18 | 7 | | 1989 | Cotonou | 19 | 2 | 11 | 9 |
2. Resistance to other antimalarial drugs: Resistance to
amodiaquine: an in vivo study was published in 1990 by C.P. Raccurt
and Coll. (8). For 69 children living on the coast, with a parasite
count superior to 1000/µL and treated with 35 mg/kg over a 3 day
period, only one treatment failed (1.4%). &nb; Resistance to the
chloroquine/proguanil combination: a case of failure of this
prophylaxis was published by J. Martin and Coll. in 1992 (20). &nb; Resistance to
quinine: a case of relapsing into illness after a treatment with
quinine was noted by C. Longuet and Coll., however, it is
impossible to say if the contamination occurred in Benin, Ghana or
Togo (34). &nb; Resistance to
mefloquine: J-P. Chippaux and Coll. note the results of in vitro
studies conducted between 1987 and 1989 (table IV).
Table IV -In vitro resistance to mefloquine in Bénin
Year | Area
Studied |
Numbers
tested |
Number of
resistants | Percentage | Reference | | 1987 | Cotonou | 33 | 3 | 1 | 9 | | 1987 | Cotonou | 50 | 2 | 4 | 7 | | 1987 | Zou | 18 | 2 | 11,1 | 7 | | 1989 | Cotonou | 13 | 1 | 8 | 9 |
| Vector Control
Vector control was studied in depth in the lake region of Ganvie
near Cotonou, from 1992 to 1999
(21, 25, 28, 29, 36, 37 ).
The site of Ganvie was chosen by Mr. Akogbeto et al. because of its
malarial transmission intensity and also because the whole local
population (20,000 inhabitants) were already using mosquito nets
(21). The rate of inoculation in Ganvie (11 infectious bites per
person per year) is three times less than that in the center of
Cotonou: this can be explained by the predominance of Anopheles melas and by the
general use of both individual and family based
measures of protection against mosquito bites (28, 29). In
1994, a trial was run of treating mosquito nets with deltamethrine
with a result of a 50% reduction of Anopheles gambiae bites
per person per night (12.5 vs. 6 for the duration of the trial) and
a reduction in the average rate of inoculation (6 vs. 3), whilst
the frequency of feverish attacks plummeted from 1.4% to 0.9%
(25).
The resistance in Ganvie of Anopheles gambiae to
deltamethrine was reported as of 1996 (29). This was confirmed in
1999 in Cotonou by F. Chandre and Coll. (36). Mr. Akogbeto and
Coll. demonstrated that Anopheles gambiae was
resistant to permethrine but still vulnerable to
deltamethrine and lmbdacyalothrine in the north of Benin,( the
cotton producing area), whilst it remained resistant to both
permethrine and deltamethrine in the center and the south of the
country (38). | The National Anti Malaria Program
1. The program was created in 1992 and revised in 1994
after two WHO evaluations (39). The strategy was: The correct
handling of malaria cases; Systematic
chemoprophylaxis for pregnant women; Encouragement to
use treated mosquito nets ; Information,
Education, Communication (IEC) and a social mobilization
program. 2. In 1997, Benin was integrated with the
21 countries selected by the WHO for the "Harare declaration for
the prevention of and the fight against malaria, within the context
of African Economic Recovery and Development” (42). For
the period between 1997-1999, the program’s strategy was thus
centered around the management of cases and the use of mosquito
nets. The training of eHealthcare agents is shown
in table V below. Tableau V - Distribution of trained personnel 41)
| Handling of serious cases | Training to
become an instructor |
Planned | 26 | | Achieved | 26 | | Cascading
formation |
Planned | 180 | | Achieved | 145 | Handling of
straight forward cases |
Planned | 90 | | Achieved | 0 |
Microscopic diagnosis |
Planned | 30 | | Achieved | 25 | | Dousing and
spraying techniques |
Planned | 225 | | Achieved | 225 | Prevention and
control of epidemics |
Planned | 0 | | Achieved | 0 |
3. Where
possible, Anti-Malaria action is integrated on a peripheral level
with basic first line health care. For
example, in 1996, 24 doctors received intermediate level
multi-disciplinary training covering, amongst others things
malaria, the extended vaccination program, acute respiratory
disorders and the fight against diarrhea related diseases
(31). 4. The creation of an original micro-
project "tontine moustiquaire" a revolving fund for
the purchase of mosquito nets. The goal of the project is to widely
promote the use of insecticide treated mosquito nets
(39). | Research Institutions
Not documented.
| Advice to travelers.
The « Centre National (Français) de Surveillance de la
Chimiosensibilité » (The national centre (French) for the
Monitoring of Chemosensitivity) placed Benin in group
III, which includes countries suffering from " highly
chemoresistant plasmodium falciparum bordering
on poly-resistant".
According to the B.E.H. n°24-25 of the 14th June 2005, Benin
is classified in chloroquine-resistance group III. This signifies
that a traveler spending less than 3 months in the country should
take the Mefloquine or the Atovaquone-Proguanil combined
treatment.
Further more, the conditions of the trip should always be taken
into account: humid season Vs dry ? Staying in towns or in the
countryside ? Staying at a hotel or in a traditional
dwelling ? More often than not simple measures of precaution
against mosquito bites are sufficient.
| Bibliography
(only the first author is mentioned)
1. SUN R.J. - Clinical observations on 196 cases of falciparum
malaria in Benin, West Africa. Chi Seng Chung Hsueh Yu Chi Seng
Chung Ping Tsa Chih 1984 ; 2 : 219.
2. HERCBERG S. - Relationship between anaemia, iron and folacin
deficiency, haemoglobinopathies and parasitic infection. Hum.
Nutr. Clin. Nutr. 1986 ; 40 : 371-379.
3. LE BRAS J. - Chloroquine-resistant falciparum malaria in
Benin. Lancet 1986 ; ii : 1043-1044.
4. ROSENHEIM M. - Five cases of chloroquine-resistant malaria in
Benin, Africa. Trans. R. Soc. Trop. Med.
Hyg. 1987 ; 81 : 498.
5. DANIS M. - Evolution de la chimiorésistance des cas de paludisme
à Plasmodium falciparum d'origine
africaine dans un hôpital parisien. Comparaison avec les données
observées sur le terrain et conséquences thérapeutiques. Bull.
Soc. Path. Exot. 1987 ; 80 : 490-496.
6. DJIVOH C. - Faible niveau de chloroquinorésistance
de Plasmodium falciparum dans la
province du Zou au Bénin. Bull. Soc. Path. Exot. 1988 ;
81 : 332-337.
7. CHIPPAUX J-P. - Sensitivity in vitro of Plasmodium falciparum to
chloroquine and mefloquine in two régions of Benin. Trans. R.
Soc. Trop. Med. Hyg. 1989 ; 83 : 584-585. 8. RACCURT C.P. - Sensibilité in vivo du Plasmodium falciparum à
l'amodiaquine dans la ville de Cotonou et ses environs (Bénin).
Med. Trop. 1990 ; 50 : 21-26.
9. CHIPPAUX J-P. - Evolution de la chimiosensibilité
de Plasmodium falciparum à la
chloroquine et à la méfloquine au Bénin entre 1980 et
1989. Bull. Soc. Path. Exot. 1990 ; 83 :
320-329.
10. BOULARD J-C. - Une étude de la morbidité palustre dans un
service hospitalier de pédiatrie au Bénin (Afrique de l'Ouest) en
1988 et 1989. Med. Trop. 1990 ; 50 : 315-320.
11. KODJOH N. - Manifestations digestives du paludisme chez
l'adulte en zone endémique. Ann. Gastroenterol. Hepatol.
1990 ; 26 : 279-284.
12. CHIPPAUX J-P. - Note sur le passage transplacentaire
de Plasmodium falciparum chez des
parturientes non fébriles en région
holo-endémique. Bull. Soc. Path. Exot. 1991 ; 84 :
458-464.
13. VELEMA J-P. - Malaria morbidity and mortality in children under
three years of age on the coast of Benin, West Africa. Trans.
R. Soc. Trop. Med. Hyg. 1991 ; 85 :
430-435.
14. GUIGUEMDE T.R. - Point actuel sur la chimiorésistance du
paludisme des sujets autochtones dans les états de l'OCCGE (Afrique
de l'Ouest). Ann. Soc. belge Med. trop. 1991 ; 71
: 199-207.
15. IBHANESEBHOR S.E. - Malaria parasitaemia in neonates with
predisposing risk factors for neonatal sepsis : report of six
cases. Ann. Trop. Paediatr. 1992 ; 12 :
297-302. 16. AKOGBETO M. - Le paludisme urbain côtier à Cotonou
(République du Bénin). Etude entomologique. Rev.
Epidemiol. Sante Publ. 1992 ; 40 : 233-239. 17. CHIPPAUX J-P. - Etude de la morbidité palustre et de la
gravité des accès pernicieux chez les porteurs du trait
drépanocytaire. Rev. Epidemiol. Sante Publ. 1992 ; 40 :
240-245.
18. CHIPPAUX J-P. - Parasitémies à Plasmodium falciparum
ou Plasmodium malariae chez les
porteurs du trait drépanocytaire dans différents biotopes du Bénin.
Rev. Epidemiol. Sante Publ. 1992 ; 40 : 246-251.
19. IBHANESEBOHR S.E. - Placental malaria and pregnancy outcome.
Int. J. Gynaecol. Obstet. 1992 ; 37 : 247-252.
20. MARTIN J. - Résistance de Plasmodium falciparum à
l'association chloroquine-proguanil. Un cas en provenance du
Bénin. Presse Med. 1992 ; 21 : 678.
21. AKOGBETO M. - Malaria transmission in the lagoon area of
Cotonou, Benin. Parassitologia 1992 ; 34 : 147-154.
22. COLUZZI M. - Advances in the study of Afrotropical malaria
vectors. Parassitologia 1993 ; 35 suppl. : 23-29.
23. GOPINATH R. - Concurrent infections with falciparum malaria in
travellers to West Africa. Can. Comm. Dis. Rep. 1994 ;
20 : 53-58.
24. JOSSE R. - Bénin : de l'initiative de Bamako à l'éradication du
ver de Guinée. Med. Trop. 1994 ; 54 : 113-116.
25. AKOGBETO M. - Impact des moustiquaires imprégnées d'insecticide
sur la morbidité palustre : résultats préliminaires. Med.
Trop. 1995 ; 55 suppl.4 : 118-119. 26. RODIER M.H. - Seroprevalences of toxoplasma, malaria,
rubella, cytomegalovirus, HIV and treponemal infections among
pregnant women in Cotonou, Republic of Benin. Acta Tropica
1995 ; 59 : 271-277.
27. COMLANVI E.C. - Étude de la chloroquinorésistance au Nord Bénin
(tests in vivo). Mal. Inf. Dis. Afr. 1995 ; n°2 : 24-25.
28. AKOGBETO M. - Étude entomologique sur la transmission du
paludisme côtier lagunaire : cas d'un village construit sur un lac
d'eau saumâtre. Ann. Soc. belge Med. trop. 1995 ; 75 :
219-227.
29. AKOGBETO M. - Impact des moustiquaires imprégnées de
deltaméthrine sur la transmission du paludisme dans un milieu
côtier lagunaire, Bénin. Bull. Soc. Path. Exot. 1996 ;
89 : 291-298.
30. DOSSOU-GBETE L. - Malaria attack diagnosed by the tympanum :
febrile otalgia. Arch. Pediatr. 1996 ; 3 :
509. 31. COMLANVI E.C. - Intégration de la lutte antipaludique aux
programmes de santé. Mal. Inf. Dis. Afr. 1996 ; n°5 :
51-58.
32. RASHED S. - Sustaining malaria prevention in Benin : local
production of bednets. Health Policy Plan. 1997 ; 12 : 67-76.
33. GUILLET P. - Origin and prevention of airport malaria in
France. Trop. Med. Int. Health 1998 ; 3 : 700-705.
34. LONGUET C. - Paludisme à Plasmodium falciparum :
résistance de type R1 à la quinine en Afrique de
l'ouest. Presse Med. 1998 ; 27 : 522.
35. FOURN L. - Facteurs associés à la naissance des enfants de
faible poids : une analyse multivariée. Sante 1999 ; 9 :
7-11.
36. CHANDRE F. - Status of pyrethroid resistance in Anopheles gambiae sensu
lato.Bull. WHO 1999 ; 77 : 230-234.
37. AKOGBETO M. - Infectivité d'Anopheles gambiae
vis-à-vis du Plasmodium falciparum dans le
milieu côtier lagunaire du Bénin. Bull. Soc. Path. Exot.
1999 ; 92 : 57-61.
38. AKOGBETO M. - Résistance des vecteurs du paludisme vis-à-vis
des pyréthrinoïdes utilisés pour l'imprégnation des moustiquaires
au Bénin, Afrique de l'ouest. Bull. Soc. Path. Exot.
1999 ; 92 : 123-130.
39. KINIFO R. - La promotion à grande échelle des moustiquaires
imprégnées au Bénin. Une initiative à base communautaire : la
tontine moustiquaire. IIIème Conférence Panafricaine sur le
Paludisme, Nairobi, Kenya, 21-26 juin 1998.
40. WAGBATSOMA V.A. - Towards malaria control : the knowledge of
health care providers about mosquito and malaria transmission.
Cent. Afr. J. Med. 1999 ; 45 : 4-6.
41. RASHED S. - Determinants of the permethrin impregnated bednets
(PIB) in the Republic of Benin : the role of women in the
acquisition and utilization of PIBs. Soc. Sci. Med. 1999 ; 49 :
993-1005.
42. KASSANKOGNO Y. - Aperçu sur le programme de lutte contre le
paludisme africain pour la période 1996-1997. Mal. Inf. Dis.
Afr. 1999 ; n°9bis : 52-61.
43. STENGER S. - Comportements et attitudes pratiques des expatriés
vis-à-vis du paludisme dans six pays d'Afrique. Mémoire D.U.
médecine et santé publique tropicales, Université Aix-Marseille,
2000, 30 pages.
44. AKOGBETO M. - Le paludisme côtier lagunaire à Cotonou : données
entomologiques. Santé 2000 ; 10 : 267-275.
45. RAHIMY M.C., GANGBO A., ADJOU R. et Coll. - Effect of active
prenatal management on pregnancy outcome in sickle cell disease in
an African setting. Blood 2000 ; 96 : 1685-1689. |
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