The chemosusceptibility and genetic polymorphism of Plasmodium falciparum populations from 48 patients hospitalized for malaria at the Hospital Principal in Dakar, Senegal were investigated during the 2002 malaria transmission season. Sixty-two percent of the isolates collected were from patients with severe malaria and 38% were from patients with mild malaria. In vitro activities of chloroquine, quinine, cycloguanil, atovaquone, mefloquine, halofantrine, and artesunate were evaluated. The prevalence of mutations in the Plasmodium falciparum dihydrofolate reductase (dhfr) and dihyropteroate synthetase (dhps) genes and the P. falciparum chloroquine resistance transporter (Pfcrt) gene associated with cycloguanil, pyrimethamine, sulfadoxine, and chloroquine resistance were estimated. The genetic polymorphism of the parasite populations was evaluated by analysis of the highly polymorphic regions of merozoite surface protein 1 (msp1) block 2 and msp2. Seventy percent of the isolates were assessed by an in vitro assay. Fifty-two percent of the isolates were chloroquine resistant, 45% were cycloguanil resistant, and 24% were atovaquone resistant. Four percent had low susceptibility to quinine. The Pfcrt and dhfr mutations were associated with in vitro chloroquine- and antimetabolic drug-resistant isolates, respectively. Approximately 70% of the isolates contained two or more clones. Genetic diversity of P. falciparum was high. The prevalence of allelic family K1 of msp1 was 68%. Isolates of P. falciparum were highly resistant to chloroquine, cycloguanil and atovaquone. The transmission rate of malaria in Dakar is low but a high degree of genetic polymorphism can increase severe malaria, as shown by persons coming to Dakar from areas highly endemic for malaria. Areas with urban malaria should use vector control measures and efficient chemoprophylaxis for non-immune populations.
Using DNA chip technology and real-time quantitative PCR, molecular profile of HBV strains infecting blood donors and patients in Dakar, Sénégal was studied. All HBsAg-positive blood donors (n = 175) and all patients who presented with chronic hepatitis B (n = 29) between 1st June 2003 and 31st July 2003 were studied. One patient, a blood donor, was coinfected by HCV, and nine patients had anti-HDV antibodies. Few persons in either group were HBeAg-positive. Viral load values were relatively low but correlated with biochemical abnormalities. Patients were infected mainly by genotype E (72%). Patients infected by genotype A (28%) tended to be younger than other patients. There was no significant difference between the blood donors and the patients with hepatitis B as regards virological markers, including viral load, when the HBV genotype was taken into account. The BCP A1762T and G1764A mutations were found in four patients and one patient, respectively; the two mutations were never found in the same patient. The W28* mutation at position 1896 of the core was detected in 19 of the 32 genotyped patients, 18 (83%) of whom had genotype E infection. ALT levels were not influenced by HBV mutations. This study shows a low frequency of clinical signs in HBsAg-positive blood donors, a relatively low level of viral replication, and a high frequency of pre-core mutants in this West African population. These results underline the importance of molecular characterization of HBV infection as specific treatments become available in this region.
BackgroundWe evaluated the short-term spontaneous fluctuations of HBV DNA and HBsAg levels in Senegalese patients with chronic infection with hepatitis B virus and normal ALT and determined factors related to these fluctuations.MethodA total of 87 patients with persistent normal ALT values were enrolled in the study. Serum samples were obtained at three different visits, with an interval of 2 months (M0, M2, and M4), and without initiating anti HBV treatment. Levels of HBV DNA, quantitative HBsAg, ALT and AST, genotyping and viral DNA mutations were analyzed.ResultsAmong the 87 patients, genotype E was predominant (75%). The median HBV DNA level was 2.9 log10 IU/mL [2.2-3.4], 2.7 log10 IU/mL [2.1-3.6] and 2.7 log10 IU/mL [2.1-3.4] at M0, M2 and M4, respectively. The values ranged from <1.1 to 7 log10 IU/mL and 55 (63%) had HBV DNA fluctuations ≥ 0.5 log10 IU/mL between two visits. Patients in whom HBV DNA fluctuated ≥0.5 log10 IU/mL between M0 and M2 also had significant fluctuations between M2 and M4, while patients with stable HBV DNA between M0 and M2 showed a stable viral load between M2 and M4. The only factor found to be associated with HBV DNA fluctuations ≥ 0.5 log10 IU/mL was a low BMI (<21 kg/ m2). HBsAg levels were not correlated with HBV DNA levels.ConclusionSixty-three percent of the enrolled Senegalese population showed a large, short-term fluctuation of HBV DNA levels. Such fluctuations may have an impact on therapeutic management, requiring closer monitoring.
A severe epidemic of serogroup A meningococcus meningitis occurred in the northwest Central African Republic from January to March 1992. Strains from 24 patients were characterized using serotyping, testing of susceptibility to antibiotics, and multilocus enzyme electrophoresis. In 23 of the 24 patients the causal strain was found to be 4:P1.9/clone III-1. These results indicate that such strains continue to spread in Africa and have taken hold in areas outside the "meningitis belt." This may be a consequence of changing climatic conditions.
Diseases always have a significant impact during military deployments. We evaluated the operational impact of health problems observed in a French infantry battalion (n = 690) during a 4-month assignment in Ivory Coast. In all, 55.7% of soldiers consulted at least once and sought care for 608 health problems. A total operational incapacity was observed in 22.2% of cases (7.6/1,000 person-days). The 5 diseases causing the greatest operational incapacity were diarrhea (2.1 days lost/1,000 person-days), musculoskeletal diseases and injuries (53.7 days), malaria (29 days), dental diseases (30.9 days), and fevers of undetermined origin (7 days). The incidence of diarrhea and skin infections was higher in rank-and-file troops than among noncommissioned officers. It was also higher during the mission's first month, when individual susceptibility to infections is suspected to be highest. Some diseases that are not serious nonetheless have a significant operational impact and should be better studied to determine preventive measures.
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