High level of sensitivity to chloroquine of 72 Plasmodium falciparum isolates from southern Cameroon in January 1985.

The sensitivity to chloroquine, quinine and mefloquine of Plasmodium falciparum isolates from 3 areas of southwest Cameroon was evaluated using an in vitro microtest with estimation of parasite growth by 3H-hypoxanthine incorporation. Among 2,429 children examined, P. falciparum was found on thin smears in 124 of them, 76 isolates were submitted to in vitro tests and 72 were successful. In the locations studied, some of which are close to the area of Limbe where in vivo resistance has been reported, all 72 isolates were found fully sensitive to low concentrations of chloroquine (mean EC50 5.9 ng/ml or 18.5 nmol/l of medium). In 47 of these isolates simultaneously tested using WHO microtest predosed plates, the sensitivity was identical. Out of 39 tests performed with quinine, 35 were successful. While most strains responded to low concentrations, some showed a decreased sensitivity to the drug, the EC50 of 4 of them being in the range 230-300 nmol/l. Each of the 17 isolates tested with mefloquine was susceptible to very low concentrations of freshly prepared drug solution. While chloroquine-resistant strains may already exist in Cameroon, the present study suggests that they would be restricted to a limited area and are not widespread. Data also suggest that monitoring of the sensitivity of P. falciparum to quinine might soon be necessary.

[Cysticercosis and epilepsy: a case-control study in Mbam Valley, Cameroon]. / Cysticercose et épilepsie: étude cas-témoins dans la Vallée du Mbam, Cameroun.

The impact of neurocysticercosis in Africa is not well known, and its role in the occurrence of epilepsy is not well defined. The concomitant high prevalence of both diseases in this region suggests a causal association of cysticercosis and epilepsy. The few attempts to find such a link in Africa have yielded discordant data. In order to answer this question, we conducted a case-control study between June and August 1998 in the Bilomo village in Central Cameroon, where a recent study had demonstrated very high epilepsy prevalence of 58/1000. Ninety-three epilepsy patients and eighty-one age matched controls were included. All subjects were examined by a neurologist and serology for cysticercosis was performed using an ELISA method. Serologies for cysticercosis were positive in twenty-nine out of one hundred and seventy four patients (16.7%; 95% CI: 11.6-23.2). Seventeen cases (18.3%) and twelve controls (14.8%) had a positive serology The odd ratio was 1.3 (95% CI: 0.6-3.0). This study was not in favour of an epidemiological relationship between cysticercosis infection and epileptic disorders.

[Center of multidrug-resistant malaria in a forest zone of Cameroon revisited after 14 years]. / Un foyer de paludisme multi-resistant en zone forestiere au Cameroun revisite 14 ans apres.

In vitro sensitivity of Plasmodium falciparum to chloroquine, amodiaquine, quinine and pyronaridine was assessed using the DELI microtest method in 2000. Isolates were collected on the La Nyé'eté rubber plantations located in a forest zone 45 km southeast of Kribi, Cameroon. Comparison with results of the last survey in 1986 showed that chloroquine resistance has remained stable (61% versus 56%). Sensitivity to amodiaquine and pyronaridine was high (76.5% and 89.5% respectively) in all isolates including chloroquine-resistant isolates. Despite intensive use in the area, quinine remained highly effective (sensitivity, 80%). These results indicate that chloroquine sensitivity has remained relatively stable in this resistant zone and that little cross-resistance with amodiaquine and pyronaridine has developed. These findings hold the promise for an alternative treatment of uncomplicated Plasmodium falciparum malaria in chloroquine-resistance areas.

[New focus of chloroquine-resistant malaria in a forestry zone in Cameroon]. / Nouveau foyer de paludisme chloroquino-résistant en zone forestière au Cameroun.

In vitro sensitivity of P. falciparum to chloroquine and quinine was studied in Hevecam rubber plantations of la Nyete in Cameroon, located at 45 km in the south east of Kribi in a forest area. More than half of the isolates studied (14/25) were resistant to chloroquine (EC50 greater than 80 nmole/l). The mean EC50 and EC99 were 113 nmole/l and 4,110 nmole/l respectively. The sensitivity to quinine was decreased, as compared to other area of the country. Kribi is the third area of chloroquine-resistance known in Cameroon.