Area : 267,700 km²
Population : 1,014,976 inhabitants (census 1993).   It is estimated that 50% of the population is urban, and 50% rural.
Official language : French
Currency : Franc CFA (1 euro = 656 FCFA)
Bordering countries : Equatorial Guinea, Cameroon, Congo 
Capital city : Libreville
Major cities : Libreville, Lambaréné, Franceville. 

In Malaria in Gabon is of the stable equatorial type: anophelian transmission is intense and endemic. Human immunity is acquired within the first five years of life. 30% to 50% of children suffering from fever are malaria-infected, regardless of the time of the year. Severe forms of malaria are found mainly in young children, and are far less frequent in immune adults. Libreville, Franceville and Lambaréné are faced with urban malaria. In 1987, in education institutions, the plasmodic index ranged from 11% to 32% in the south-east, reached 65% in the north, and ranged from 6 to 18% in urban environments ( 09 ). In 1990, the same index was 31% in the Ngounié region (Mouila), 32.5% in the High-Ogooué (Franceville), and 26% in Libreville ( 19 ). 

In 1994, the plasmodic index was 43.3% in Akou, a district of Franceville, and 39.8% in Benguia, a village of 180 inhabitants close to Franceville ( 39 ). In 1986, in Libreville ( 09 ), 29.2% of the children suffering from fever attacks were affected by malaria, and in 1992 the figure was 18.5% ( 54 ). 

Gabon is one of the African countries where the highest number of studies on chemoresistances have been carried out, in Libreville (Libreville University, French Army), in Lambaréné (Albert Schweitzer hospital) and in Franceville (CIRMF).

Recommendations of the National Anti Malaria Program :

 Following the meeting of the July 2003 consensus, the NAMP recommends the artésunate + amodiaquine association as first line treatment. There isn' t any precision about the second line treatment.

In 1984, in Lambaréné, a study reported for the first time the in vitro chloroquine resistance of Plasmodium falciparum: 9 of 31 strains tested were resistant (19%)( 05). 
In vivo resistance was envisaged in 1982 ( 04 ), signalled in 1985 ( 06) and evidenced in 1987 ( 08 ).
Since then, numerous studies have been carried out.   They are listed in the two tables below.

Table I – In vivo chloroquine resistance in Gabon

Table II – In vitro chloroquine resistance in Gabon.   

1. Amodiaquine:
It should be noticed, oddly enough, that the first publications on the subject did not appear before 1996: in Libreville, an in vivo study on 100 patients affected with hematozoa, showed that the efficacy of amodiaquine (30 mg/kg for 3 days) reached 100% (60). 
Its efficacy was 71.8% for 71 patients in Lambaréné (48). 
In 1997, the efficacy was 100% for 27 patients (83).
In 1999, it was still 84.2% as reported by P. Brasseur et al. (75) and 71% as reported by S. Looareesuwan et al.   (71).
In 2002, the efficacy reached 89.6% as reported by M. Atjuik et al. (92) and only 46% for C.T. Bagaphou (94).

2. Quinine:
In 1994, 68% of RI type resistance was reported in Lambaréné (34); this value reached 72% in 1995 (44 ). 
In 1998, in an in vitro study, B. Pradines et al. reported 32% of Libreville strains with a sensitivity drop (62).   On Lambaréné strains, however, the sensitivity drop concerned only 19% of the strains (65). 
In 2000, C.H. Brandts et al. did not find any resistance on 33 strains tested in vitro (82).
In 2003, J.M. Ndong et al. observed 100% of in vitro sensitivity on 60 isolates from Franceville, and 89.8% on 62 isolates of Bakoumba (100).

3. Mefloquine:
This drug was recommended as early as 1982 by M. Danis et al. (04).
In 1994, 40 plasmodial strains were tested in vitro and no resistance was evidenced (36).   In 1996, P.D. Radloff et al. confirmed these excellent results in an in vivo study (47). 
In 1998, in Lambaréné, B. Lell et al. noted that only 13% of 41 patients treated were aparasitemic on the seventh day (64).   Yet, still in Lambaréné, 100% of the 33 strains submitted to in vitro tests were sensitive to mefloquine (65   ).
In 2000, C.H. Brandts et al. could not find any resistance on 33 strains tested in vitro (82    ).
In 2003, J.M. Ndong et al. observed 79% of in vitro sensitivity on 60 isolates from Franceville and 52.5% on 62 isolates from Bakoumba (100    ).

4. Halofantrine:
Its use was recommended as early as 1991, by D. Richard-Lenoble et al. for the treatment of simple malaria in children (23    ).
In 1992, D. Baudon et al. recommended it as a ‘’radical return cure’’ for travelers returning from Gabon after a stay of at least three months (25).   As a treatment against simple malaria, it claims an efficacy of 100% in Libreville (29) and in Lambaréné (32    ).
In 1994, in Lambaréné, the efficacy of a micronized formulation was also demonstrated (34, 37). 40 strains tested in vitro exhibited no resistance (36    ).
In 1997, J.E. Touze et al. showed that a second dose of halofantrine (250 mg) as a second-line treatment on the seventh day, exhibited the same efficacy as that of the conventional dose (1,500 mg) (59    ). 
In 1998, for 32 strains tested in vitro, the resistance rate was 18.75% (65).   In 2000, for 32 other strains tested, no resistance was observed (82). In 2003, for 62 isolates, the resistance rate was 18.2% (100    ).

5. Sulfadoxine-Pyrimethamine Combination (SPC):
As early as 1988, G.D. Burchard and E. Winckler published a case that was resistant to chloroquine and to the SPC.   The patient was cured through the administration of mefloquine (15    ).
In 1992, in an in vitro study, E. Winckler et al. showed that 8 of the 27 strains tested were SPC-resistant (30%) (36    ).
In 1997, a SPC cure exhibited an efficacy of 94% (51    ).
In 1998, in Lambaréné, 53 out of 77 patients (69%) were cured at D7 with a single dose of SPC, which indicates nevertheless a treatment failure rate of 41% (64   ).
In 1999, in Franceville, 12.1% of the 66 sick children treated with SPC, exhibited a RI type resistance, and 18.2% exhibited a RII type resistance.   No RIII type resistance was reported (78    ).

6. Artemisinine derivatives:
The first study on artemether was published in 1994: out of 47 sick children (28 simple malaria attacks and 19 acute attacks), an artemether cure has an efficacy of 100%, with two relapses at D14 and D21 (38    ). 
Artemisinine was tested in vitro in 1998, in Lambaréné, on 33 plasmodial strains, of which 10 exhibited a sensitivity drop (30.3%) (65    ).
In 2003, a test on artesunate – consisting of a 3 day cure - was carried out on 50 children age 4-15 ; the cure rate was 92% at D14 and 72% at D28 (98 ).

7. Antibiotics:

Clindamycine:
In 1993, P.G. Kremsner et al. treated 38 simple malaria attacks with a dose of 5 mg/kg of clindamycine, twice a day: they cured 37 patients and reported one RI type resistance (31 ).

Fosfidomycine:
In 2002, M.A. Missionou et al. achieved a curing rate of 89% with fosfidomycine over 5 days, 88% over 4 days and 60% over 3 days.   However, the cohort tested was low, i.e. 9, 9 and 8 simple malaria attacks respectively (89 ). 

8. Combinations others than the sulfadoxine-pyrimethamine combination:

Sulfadoxine-pyrimethamine-mefloquine combination (Fansimef®):
In 1992, M. Kombila et al. tested this combination for the first time, on a cohort of 39 children age 5 to 12: in 48 hours, 38 children had negative parasitemia, and in 72 hours the curing rate reached 76% (27    ).
In 1995-1996, B. Lell et al. tested the combination in Lambaréné on 74 patients suffering from simple malaria attacks: the parasitological curing rate at D7 was 67% (64).

Atovaquone-proguanil combination (Malarone®):
In 1996, P.D. Radloff et al. tested the combination on 71 patients: 62 were cured (87.3%) (48    ). 
In 1999, S. Looareesuwan et al. tested it on 63 patients and reported only one failure (1.6%) (71    ). 
In 2002, C.T. Bagaphou reported 10.4% of therapeutical failures during a test on 50 patients (94 ).

Other combinations: