Genes,diet and uric acid nephrolithiasis

Uric acid represent the final product of purine metabolism: one-third of daily uric acid production is excreted by the gastrointestinal tract and two-thirds by the kidney. A high uric acid excretion with urine, a low urine volume due to dehydration and an acidic urinary pH value have been suggested to be the most important risk factor for uric acid nephrolithiasis (UAN). Recently mutation analysis showed that a variant (Ala62Thr) in a specific protein isoform (Talanin) is associated with UAN. We found that this variant is rather common in the Sardinian (32%) and Sicilian populations (23%), that are Mediterranean islands, as well as in the Italian peninsula (27%). On the contrary, in Burkina Faso and in Benin, both sub-Saharan countries, mesoendemic regions for Plasmodium falciparum malaria and other parasite infections, a low incidence of this variant was found (1.1% and 1.2% respectively). In Burkina Faso and in Benin, the low incidence of Ala62Thr variant is associated with low presence of UAN and the major classes of stones reported are calcium oxalate and calcium phosphate. These low frequencies for Ala62Thr predisposing to UAN in Burkina Faso and in Benin may represent the result of a selective mechanism where the arid conditions of territory and the characteristic alimentary habits of this part of Africa may represent an obstacle to the expansion of mutated allele.     

Identification of a novel gene and a common variant associated with uric acid nephrolithiasis in a Sardinian genetic isolate

Uric acid nephrolithiasis (UAN) is a common disease with an established genetic component that presents a complex mode of inheritance. While studying an ancient founder population in Talana, a village in Sardinia, we recently identified a susceptibility locus of approximately 2.5 cM for UAN on 10q21-q22 in a relatively small sample that was carefully selected through genealogical information. To refine the critical region and to identify the susceptibility gene, we extended our analysis to severely affected subjects from the same village. We confirm the involvement of this region in UAN through identical-by-descent sharing and autozygosity mapping, and we refine the critical region to an interval of approximately 67 kb associated with UAN by linkage-disequilibrium mapping. After inspecting the genomic sequences available in public databases, we determined that a novel gene overlaps this interval. This gene is divided into 15 exons, spanning a region of approximately 300 kb and generating at least four different proteins (407, 333, 462, and 216 amino acids). Interestingly, the last isoform was completely included in the 67-kb associated interval. Computer-assisted analysis of this isoform revealed at least one membrane-spanning domain and several N- and O-glycosylation consensus sites at N-termini, suggesting that it could be an integral membrane protein. Mutational analysis shows that a coding nucleotide variant (Ala62Thr), causing a missense in exon 12, is in strong association with UAN (P=.0051). Moreover, Ala62Thr modifies predicted protein secondary structure, suggesting that it may have a role in UAN etiology. The present study underscores the value of our small, genealogically well-characterized, isolated population as a model for the identification of susceptibility genes underlying complex diseases. Indeed, using a relatively small sample of affected and unaffected subjects, we identified a candidate gene for multifactorial UAN.     

Identification and distribution of a GABA receptor mutation conferring dieldrin resistance in the malaria vector Anopheles funestus in Africa

Growing problems of pyrethroid resistance in Anopheles funestus have intensified efforts to identify alternative insecticides. Many agrochemicals target the GABA receptors, but cross-resistance from dieldrin resistance may preclude their introduction.Dieldrin resistance was detected in An. funestus populations from West (Burkina Faso) and central (Cameroon) Africa, but populations from East (Uganda) and Southern Africa (Mozambique and Malawi) were fully susceptible to this insecticide. Partial sequencing of the dieldrin target site, the ??-aminobutyric acid (GABA) receptor, identified two amino acid substitutions, A296S and V327I. The A296S mutation has been associated with dieldrin resistance in other species. The V327I mutations was detected in the resistant sample from Burkina Faso and Cameroon and consistently associated with the A296S substitution. The full-length of the An. funestus GABA-receptor gene, amplified by RT-PCR, generated a sequence of 1674 bp encoding 557 amino acid of the protein in An. funestus with 98% similarity to that of Anopheles gambiae. Two diagnostic assays were developed to genotype the A296S mutation (pyrosequencing and PCR-RFLP), and use of these assays revealed high frequency of the resistant allele in Burkina Faso (60%) and Cameroon (82%), moderate level in Benin (16%) while low frequency or absence of the mutation was observed respectively in Uganda (7.5%) or 0% in Malawi and Mozambique.The distribution of the Rdl^R mutation in An. funestus populations in Africa suggests extensive barriers to gene flow between populations from different regions.     

Hereditary elliptocytosis in West Africa: frequency and repartition of spectrin variants

Hereditary Elliptocytosis (HE) is a hemolytic disorder inherited as autosomal-dominant trait and characterized by elliptically shaped erythrocytes. Preliminary studies in France have showed a high proportion of HE patients of black extraction (West Africa and Antilles). In order to confirm this prevalence, we made a systematic search for HE in West Africa: Benin, Burkina Faso, Ivory Coast, Togo. The diagnosis of elliptocytosis was established by the observation of a high percentage (greater than 70%) of characteristic regular and symmetric elliptic red cells after fixation in 0.3% glutaraldehyde saline buffer. The diagnosis of HE was confirmed by cytological studies of related members and/or the discovery of a well defined molecular variant of spectrin, the main protein of erythrocyte membrane skeleton. We found: in Abidjan centre 6 HE out of 1,000 subjects representative of main ethnic groups; in Lome Centre 6 cases out of 750 subjects originated from the South or Central areas of Togo; in Cotonou Centre 5 cases out of 1,000 subjects originated from the South area of Benin; in Bobo Dioulasso centre 6 HE out of 700 subjects. From this multicentre studies HE appears roughly 10 times more frequent in West Africa than in Europe or USA where incidence was estimated at between 2.5 and 5 cases per 10,000. Tryptic digestion of spectrin revealed that: 10 patients from different ethnic groups have the most frequent variant found in our laboratory (21 kindreds) and named spectrin alpha I/65. Five cases originated from limited areas in the South of Benin and Togo and related to closed ethnic groups have the variant Sp alpha I/46.     

Variation and geographical distribution of ploidy levels inPennisetum sectionBrevivalvula (Poaceae) in Burkina Faso,Benin and southern Niger

Pennisetum sect.Brevivalvula is a species complex characterized by polyploidy and apomixis. Ploidy level was assessed by DAPI-flow cytometry for 304 plants of the section, originating from Burkina Faso, Benin and southern Niger. The results were confirmed for 54 plants based on chromosome counts. The samples show four euploidy levels (with x = 9) distributed among five species:P. hordeoides (2n = 36, 54),P. pedicellatum (2n = 36, 45, 54),P. polystachion (2n = 18, 36, 45, 54),P. setosum (2n = 54), andP. subangustum (2n = 18, 36, 54). The geographical distribution of these ploidy levels seems related to major vegetation zones present in Africa. Diploid populations ofP. polystachion andP. subangustum were found in the Banfora area, in Burkina Faso.     

Three years of insecticide resistance monitoring in Anopheles gambiae in Burkina Faso: resistance on the rise?

ABSTRACT: Background and methods A longitudinal Anopheles gambiae s.l. insecticide-resistance monitoring programme was established in four sentinel sites in Burkina Faso. For three years, between 2008 and 2010, WHO diagnostic dose assays were used to measure the prevalence of resistance to all the major classes of insecticides at the beginning and end of the malaria transmission season. Species identification and genotyping for target site mutations was also performed and the sporozoite rate in adults determined. RESULTS: At the onset of the study, resistance to DDT and pyrethroids was already prevalent in An. gambiae s.l. from the south-west of the country but mosquitoes from the two sites in central Burkina Faso were largely susceptible. Within three years, DDT and permethrin resistance was established in all four sites. Carbamate and organophosphate resistance remains relatively rare and largely confined to the south-western areas although a small number of bendiocarb survivors were found in all sites by the final round of monitoring. The ace-1R target site resistance allele was present in all localities and its frequency exceeded 20% in 2010 in two of the sites. The frequency of the 1014 F kdr mutation increased throughout the three years and by 2010, the frequency of 1014 F in all sites combined was 0.02 in Anopheles arabiensis, 0.56 in An. gambiae M form and 0.96 in An. gambiae S form. This frequency did not differ significantly between the sites. The 1014 S kdr allele was only found in An. arabiensis but its frequency increased significantly throughout the study (P = 0.0003) and in 2010 the 1014 S allele frequency was 0.08 in An. arabiensis. Maximum sporozoite rates (12%) were observed in Soumousso in 2009 and the difference between sites is significant for each year. CONCLUSION: Pyrethroid and DDT resistance is now established in An. gambiae s.l. throughout Burkina Faso. Results from diagnostic dose assays are highly variable within and between rounds of testing, and hence it is important that resistance monitoring is carried out on more than one occasion before decisions on insecticide procurement for vector control are made. The presence of 1014 S in An. gambiae s.l., in addition to 1014 F, is not unexpected given the recent report of 1014 S in Benin but highlights the importance of monitoring for both mutations throughout the continent. Future research must now focus on the impact that this resistance is having on malaria control in Burkina Faso.     

In vivo chemosensitivity of Plasmodium falciparum to chloroquine in Burkina Faso: development of resistance 1988-1990]

A study of Plasmodium falciparum sensitivity to chloroquine was carried out in 1988 and 1990 in 5 localities, representatives of different climatic areas of Burkina Faso. The 7-day in vivo standard test performed in 1988 showed a total clearance failure of 25%. No significant difference with 1990 data was found, except for an increase of the resistance in the area of Fada N'Gourma, close to the border with Benin, Niger and Togo.     

Circadian rhythm of photosensitivity and the adaptation of reproductive function to the environment in two populations of Arvicanthis niloticus from Mali and Burkina Faso.

Previous studies have shown that there is a circadian rhythm of photosensitivity in different rodent species of the Sahel (Burkina Faso) and that, despite the low amplitude of seasonal variations in daylength, the photoperiod may control reproductive function. The present investigation of Arvicanthis niloticus provides additional support for this hypothesis. Populations of Arvicanthis niloticus from two regions at the same latitude 1000 km apart but with different climates were studied. Oursi, Burkina Faso, has an arid climate (annual rainfall 315 mm) and Kamalé, Mali has a wetter climate (annual rainfall 1114 mm). The circadian rhythm of photosensitivity had the same features in both populations, involving inhibition of testicular activity, but the photosensitive phase began 11 h 30 min after dawn in the population from Burkina Faso and 45 min later in that from Mali. Comparison of these results with the annual variation of daylength showed that the photoperiod inhibits the reproductive activity of A. niloticus from April to December in Burkina Faso and only from mid-May to mid-August in Mali. The population of Arvicanthis niloticus living in an environment with a large and seasonally stable food supply (Mali) thus has a longer reproductive period. This corroborates results from field studies on annual variations of population density.     

Intestinal fatty acid binding protein and microsomal triglyceride transfer protein polymorphisms in French-Canadian youth

Growing evidence suggests an association between lipid abnormalities and fatty acid binding protein (FABP) and microsomal triglyceride transfer protein (MTP) gene variants. Our objectives were to determine whether Ala54Thr FABP2 and G-493T MTP polymorphisms are associated with increased risks of insulin resistance syndrome (IRS) in youth and/or modify the expression of accompanying dyslipidemia. Our study of 1,742 French-Canadians aged 9, 13, and 16 years did not provide evidence of a potential predisposition to IRS related to either FABP2 or MTP genotypes. However, we observed a heterogeneity of the FABP2 effect by IRS status on total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), and apolipoprotein B (apoB) concentrations (P for interaction=0.045, 0.018, and 0.017, respectively). Among the metabolic components of IRS, only triglyceride (TG) displayed an interaction with FABP2 polymorphism: compared with Thr/Ala and Ala/Ala, the Thr/Thr genotype was associated with a steeper increase in TC, LDL-C, and apoB parallel to TG concentrations (P <0.001). IRS did not modify the associations between the MTP polymorphism and any of the biochemical parameters. Our study suggests that the effects of FABP2 allelic variations on lipid traits are context dependent, indicating that this variant may play an important role in cardiovascular pathogenesis in the presence of IRS or hypertriglyceridemia.     

MDR1 Ala893 polymorphism is associated with inflammatory bowel disease

Crohn disease (CD) and ulcerative colitis (UC) are overlapping chronic inflammatory bowel diseases (IBDs). Suggestive evidence for linkage at chromosome 7q has been reported for both CD and UC. Contained within this region is the gene for MDR1 (multidrug resistance), a membrane transport protein for which human polymorphisms have been reported in Ala893Ser/Thr and C3435T that alter pharmacokinetic profiles for a variety of drugs. Because mdr1 knockout mice spontaneously develop colitis, exonic regions were resequenced and tested for IBD association in a large, multicenter North American cohort. Two missense mutations, Asn21Asp and Ala893Ser/Thr, as well as the expression-associated polymorphism C3435T, described elsewhere, were genotyped in the entire cohort. Significant association of Ala893 with IBD was observed by both case-control analysis (P=.002) and the pedigree disequilibrium test (PDT [P=.00020-.00030]) but not for the Asn21Asp or C3435T polymorphisms. Significant association by PDT was observed within the subset with CD (P=.0014-.00090), with similar, nonsignificant trends in a smaller subset with UC. The Ala893Ser/Thr variant is triallelic, and the associated, common allele is Ala893, with undertransmission of the 893Ser (common) and the 893Thr (rare) variants. The Ala893 variant has decreased activity compared with the 893Ser variant; therefore, the association with human IBD is consistent with the murine model of mdr1 deficiency. Taken together, these data support the association of the common Ala893 polymorphism with IBD specifically and, more broadly, provides additional support for its contribution to interindividual pharmacogenetic variation.     

Directed evolution of Aspergillus niger glucoamylase to increase thermostability

Using directed evolution and site‐directed mutagenesis, we have isolated a highly thermostable variant of Aspergillus niger glucoamylase (GA), designated CR2‐1 . CR2‐1 includes the previously described mutations Asn20Cys and Ala27Cys (forming a new disulfide bond), Ser30Pro, Thr62Ala, Ser119Pro, Gly137Ala, Thr290Ala, His391Tyr and Ser436Pro. In addition, CR2‐1 includes several new putative thermostable mutations, Val59Ala, Val88Ile, Ser211Pro, Asp293Ala, Thr390Ser, Tyr402Phe and Glu408Lys, identified by directed evolution. CR2‐1 GA has a catalytic efficiency (k_cat/K_m) at 35°C and a specific activity at 50°C similar to that of wild‐type GA. Irreversible inactivation tests indicated that CR2‐1 increases the free energy of thermoinactivation at 80°C by 10 kJ mol^?1 compared with that of wild‐type GA. Thus, CR2‐1 is more thermostable (by 5 kJ mol^?1 at 80°C) than the most thermostable A. niger GA variant previously described, THS8 . In addition, Val59Ala and Glu408Lys were shown to individually increase the thermostability in GA variants by 1 and 2 kJ mol^?1, respectively, at 80°C.     

Chitotriosidase,a prematurely orphan enzyme

Human Chitotriosidase (CHIT) is a member of the chitinase family and is synthesized by activated macrophages. Recently, a genetic polymorphism was found to be responsible for the common deficiency in CHIT activity, frequently encountered in different population. We analyzed the CHIT gene in some ethnic groups from Mediterranean and frican area, to evaluate whether the CHIT gene polymorphism correlates with the changes in environmental features and the disappearance of parasitic diseases. We evaluate the plasma CHIT activity and analyzed, by PCR, the Chit gene polymorphism in 100 Sicilian, 107 Sardinian and 99 Sub-Saharan subjects. We found an heterozygote frequency for a duplication of 24 base pair in exon 10 of 44,54% in Sicily and 32,71 % in Sardinia, whereas homozygous chit deficient were 5,45 % and 3,73%, respectively. On the contrary in Burkina Faso, a mesoendemic regio nforPlasmodium falciparum malaria and other intestinal parasites, a low incidence of CHIT mutation was found (heterozygous 2%) and any subject was homozygous for CHIT deficiency. Our results suggest that in sub-Saharan population the intact CHIT gene seems essential for sustaining resistance against chitin-coated parasitic disease, whereas the presence of CHIT gene polymorphism in Mediterranean population could be the result of a recent positive selection due to improved environmental conditions, which makes prematurely orphan this enzyme.     

The SH2B gene is associated with serum leptin and body fat in normal female twins

Src-homology-2 (SH2)-B, a Janus tyrosine kinase 2-interacting protein, has been identified recently as a key regulator of leptin and insulin sensitivity, glucose homeostasis, and body weight in mice. The aim of this study was to determine whether single-nucleotide polymorphisms (SNPs) in the human SH2B gene are associated with these variables. A tagging SNP (tSNP), Ala484Thr (rs7498665), was selected to represent five common SNPs (minor allele frequency > 0.05) in perfect linkage disequilibrium in a 16-kb region encompassing the SH2B gene. The tSNP was genotyped in 2455 white female twins (mean age, 47.4 +/- 12.6 years) from the St. Thomas' United Kingdom Adult Twin Registry (Twins United Kingdom). Ala484Thr (minor allele frequency, 0.38) was associated with serum leptin, total fat, waist circumference, and body weight (P = 0.02 to 0.04). The coding SNP has no predicted effect on protein structure or function and is likely to be in linkage disequilibrium with an as-yet unidentified functional variant in the SH2B gene. Our results support a role for SH2-B in modulating the regulation of body weight and fat by leptin in this female population. If SH2-B signaling is attenuated in diet-induced obesity, it could become a target for drug-induced leptin sensitization.     

Prevalence of the NKG2D Thr72Ala polymorphism in patients with systemic lupus erythematosus

Multiple studies have indicated that SLE incidence exhibits a strong genetic background. We studied the frequency of the natural killer group 2, member D (NKG2D) receptor Thr72Ala (rs2255336) polymorphism in patients with SLE (n = 243) and controls (n = 502) in a sample of the Polish population. The p value for SLE patients with the Thr/Thr genotype was 0.0455 and Odds Ratio (OR) = 0.3846 (95% CI = 0.1458–1.014). For the Thr/Thr and Ala/Thr genotypes we found p = 0.0135 and OR = 0.6556 (95% CI = 0.4684–0.9177). The frequency of the NKG2D 72Thr allele in patients and controls was respectively, 15 and 21%, P = 0.0046, OR = 0.6547 (95% CI = 0.4877–0.8789). Our studies may confirm that the NKG2D 72Thr gene variant may protect against the incidence of SLE.     

Multivariate characterization of morphological traits in Burkina Faso sheep

A total of 6440 female sheep from Burkina Faso were scored for seven body measurements and four qualitative morphological traits. Sampling included the three main environmental areas and sheep breeds of Burkina Faso: the Sahel area (Burkina-Sahel sheep), the Sudan-Sahel area (Mossi sheep) and the Sudan area (Djallonké sheep). Canonical analyses showed that differences in body measurements between the Sudan and the Sudan-Sahel sheep were small even though most body traits showed higher average values in the Burkina-Sahel sheep: the shortest Mahalanobis distance was found between the Sudan and the Sudan-Sahel populations (1.54), whilst that between the Sudan and the Sahelian populations was the largest (7.88). Discriminant analysis showed that most Sudan (Djallonké) individuals (60.85%) were classified as Sudan-Sahel (Mossi) individuals whilst most Burkina-Sahel individuals were classified into their environmental area of sampling (89.46%). Correspondence analyses indicated that the Burkina-Sahel sheep population clustered together with dropping ears, black and brown colour patterns and presence of wattles, the Sudan sheep were closely associated with long hair and vertical and curled ears and that the Sudan-Sahel sheep did not have clear associations with qualitative phenotypic traits. At the morphological level, the Sudan-Sahel (Mossi) sheep population can be considered a geographical subpopulation belonging to the Djallonké breed, showing some particularities, namely larger body size, due to the particular environmental condition of the area in which it is managed and a continuous gene flow from Sahelian sheep, The information reported in this study will be the basis for the establishment of further characterization, conservation and selection strategies for Burkina Faso sheep.     

Patients Are Paying Too Much for Tuberculosis: A Direct Cost-Burden Evaluation in Burkina Faso

Background

Paying for health care may exclude poor people. Burkina Faso adopted the DOTS strategy implementing “free care” for Tuberculosis (TB) diagnosis and treatment. This should increase universal health coverage and help to overcome social and economic barriers to health access.

Methods

Straddling 2007 and 2008, in-depth interviews were conducted over a year among smear-positive pulmonary tuberculosis patients in six rural districts of Burkina Faso. Out-of-pocket expenses (direct costs) associated with TB were collected according to the different stages of their healthcare pathway.

Results

Median direct cost associated with TB was US$101 (n = 229) (i.e. 2.8 months of household income). Respectively 72% of patients incurred direct costs during the pre-diagnosis stage (i.e. self-medication, travel, traditional healers'' services), 95% during the diagnosis process (i.e. user fees, travel costs to various providers, extra sputum smears microscopy and chest radiology), 68% during the intensive treatment (i.e. medical and travel costs) and 50% during the continuation treatment (i.e. medical and travel costs). For the diagnosis stage, median direct costs already amounted to 35% of overall direct costs.

Conclusions

The patient care pathway analysis in rural Burkina Faso showed substantial direct costs and healthcare system delay within a “free care” policy for TB diagnosis and treatment. Whether in terms of redefining the free TB package or rationalizing the care pathway, serious efforts must be undertaken to make “free” health care more affordable for the patients. Locally relevant for TB, this case-study in Burkina Faso has a real potential to document how health programs'' weaknesses can be identified and solved.     

Multivariate characterization of morphological traits in Burkina Faso sheep

A total of 6440 female sheep from Burkina Faso were scored for seven body measurements and four qualitative morphological traits. Sampling included the three main environmental areas and sheep breeds of Burkina Faso: the Sahel area (Burkina-Sahel sheep), the Sudan-Sahel area (Mossi sheep) and the Sudan area (Djallonké sheep). Canonical analyses showed that differences in body measurements between the Sudan and the Sudan-Sahel sheep were small even though most body traits showed higher average values in the Burkina-Sahel sheep: the shortest Mahalanobis distance was found between the Sudan and the Sudan-Sahel populations (1.54), whilst that between the Sudan and the Sahelian populations was the largest (7.88). Discriminant analysis showed that most Sudan (Djallonké) individuals (60.85%) were classified as Sudan-Sahel (Mossi) individuals whilst most Burkina-Sahel individuals were classified into their environmental area of sampling (89.46%). Correspondence analyses indicated that the Burkina-Sahel sheep population clustered together with dropping ears, black and brown colour patterns and presence of wattles, the Sudan sheep were closely associated with long hair and vertical and curled ears and that the Sudan-Sahel sheep did not have clear associations with qualitative phenotypic traits. At the morphological level, the Sudan-Sahel (Mossi) sheep population can be considered a geographical subpopulation belonging to the Djallonké breed, showing some particularities, namely larger body size, due to the particular environmental condition of the area in which it is managed and a continuous gene flow from Sahelian sheep, The information reported in this study will be the basis for the establishment of further characterization, conservation and selection strategies for Burkina Faso sheep.     

Effects of an Ala54Thr polymorphism in the intestinal fatty acid-binding protein on responses to dietary fat in humans

A polymorphism in FABP2 that results in an alanine-to-threonine substitution at amino acid 54 of the intestinal fatty acid-binding protein (IFABP) is associated with insulin resistance in Pima Indians. In vitro, the threonine form (Thr54) has a higher binding affinity for long-chain fatty acids than does the alanine form (Ala54). We tested whether this polymorphism affected metabolic responses to dietary fat, in vivo. Eighteen healthy Pima Indians, half homozygous for the Thr54 form of IFABP and half homozygous for the Ala54 form, were studied. The groups were matched for sex, age, and body mass index. Plasma triglyceride, nonesterified fatty acid (NEFA), glucose, and insulin responses were measured after a mixed meal (35% of daily energy requirements, 50 g of fat) and after a high fat challenge (1362 kcal, 129 g of fat). NEFA concentrations were approximately 15% higher after the mixed meal and peaked earlier and were approximately 20% higher at 7 h in response to the high fat test meal in Thr54 homozygotes compared with Ala54 homozygotes. Insulin responses to the test meals tended to be higher in Thr54 homozygotes, but glucose and triglyceride responses were not different.The results of this study suggest that the Thr54 form of IFABP is associated with higher and prolonged NEFA responses to dietary fat in vivo. Higher NEFA concentrations may contribute to insulin resistance and hyperinsulinemia in individuals with this allele.     

First report of the kdr mutation in Anopheles gambiae M form from Burkina Faso,west Africa

The kdr mutation, conferring resistance to pyrethroid insecticides, has been reported in several West-African populations of Anopheles gambiae S form and in the M form populations from tropical forest of Benin. We report the finding of a single M specimen collected in the rice-field area of Vallée du Kou (Burkina Faso) showing the mutation at the heterozygous state. The monitoring of kdr mutation in An. gambiae forms/species is of paramount importance to implement effective malaria control tools and may greatly improve the knowledge of the relationship between and within An. gambiae populations.     

The establishment of Neisseria meningitidis serogroup W135 of the clonal complex ET-37/ST-11 as an epidemic clone and the persistence of serogroup A isolates in Burkina Faso

We analyzed 48 invasive isolates of Neisseria meningitidis that were isolated from meningitis cases in Burkina Faso (April 2002 to April 2003). Thirty-nine of these isolates had the phenotype (serogroup:serotype:serosubtype) W135:2a:P1.5,2, eight isolates were A:4:P1.9 and one isolate was nongroupable:nonserotypable:nonserosubtypable. Genotyping of meningococcal isolates showed that W135 isolates belonged to the sequence type (ST)-11. The nongroupable isolate was of genogroup W135 and belonged to ST-192. Isolates of serogroup A belonged to ST-2859 (a member of the subgroup III/ST-5 clonal complex). W135 (ST-11) isolates involved in meningitis outbreaks in Burkina Faso differed from those involved in the Hajj-2000 associated outbreak by their pulsed-field gel electrophoresis profile. These data confirm the changing epidemiology of meningococcal infection in Burkina Faso with the establishment and expansion of serogroup W135 N. meningitidis strains of the ET-37/ST-11 clonal complex, as well as the emergence of a new clone within the subgroup III/ST-5 clonal complex.