7 research outputs found
Burden of visceral leishmaniasis in villages of eastern gedaref state, Sudan: an exhaustive cross-sectional survey.
Since December 2009, Médecins Sans Frontières has diagnosed and treated patients with visceral leishmaniasis (VL) in Tabarak Allah Hospital, eastern Gedaref State, one of the main endemic foci of VL in Sudan. A survey was conducted to estimate the VL incidence in villages around Tabarak Allah
Loss of balancing selection in the βS globin locus
<p>Abstract</p> <p>Background</p> <p>Probably the best example of the rise and maintenance of balancing selection as an evolutionary trend is the role of S-haemoglobin (HbS - rs334) in protecting from malaria. Yet, the dynamics of such a process remains poorly understood, particularly in relation to different malaria transmission rates and the genetic background of the affected populations.</p> <p>Methods</p> <p>We investigated the association of haemoglobin HbS in protection from clinical episodes of malaria in two populations/villages where malaria is endemic, but mostly presenting in mild clinical forms. Five-hundred and forty-six individuals comprising 65 and 82 families from the Hausa and Massalit villages respectively were genotyped for HbS. Allele and genotype frequencies as well as departure from Hardy-Weinberg Equilibrium were estimated from four-hundred and seventy independent genotypes across different age groups. Age-group frequencies were used to calculate the coefficient-of-fitness and to simulate the expected frequencies in future generations.</p> <p>Results</p> <p>Genotype frequencies were within Hardy-Weinberg expectations in Hausa and Massalit in the total sample set but not within the different age groups. There was a trend for a decrease of the HbS allele frequency in Hausa and an increase of frequency in Massalit. Although the HbS allele was able to confer significant protection from the clinical episodes of malaria in the two populations, as suggested by the odds ratios, the overall relative fitness of the HbS allele seems to have declined in Hausa.</p> <p>Conclusions</p> <p>Such loss of balancing selection could be due to a combined effect of preponderance of non-clinical malaria in Hausa, and the deleterious effect of the homozygous HbS under circumstances of endogamy.</p
Incidence of VL over past year, eastern Gedaref State, Sudan, May-June 2011.
<p>* The size and the colour of the circles are proportionate to VL incidence.</p
Age and sex distribution of VL cases in the past year (725 previously treated cases and 16 new cases) and of the general population, eastern Gedaref State, Sudan, May-June 2011.
*<p>Missing sex in general population: 99 (30 aged 0 to 4 years old, 18 aged 5 to 14 years old, 47 aged 15 and above, 4 with missing age).</p
Flowchart of individuals assessed for fever of at least 2 weeks duration, eastern Gedaref State, Sudan, May-June 2011.
<p>* Positive rK39 test in PKDL suspect, never treated for VL in the past. DAT: Direct Agglutination Test.</p