Prevalence of Glucose-6-phosphate Dehydrogenase Deficiency and Haemoglobin S in High and Moderate Malaria Transmission Areas of Muheza; North-Eastern Tanzania

Glucose-6-phosphate dehydrogenase (G6PD) deficiency and haemoglobin S (HbS) are very common genetic disorders in sub Saharan Africa; where malaria is endemic. These genetic disorders have been associated with protection against malaria and are therefore under strong selection pressure by the disease. In November-December 2003; we conducted a cross-sectional survey to determine the prevalence of G6PD deficiency and HbS in the population and relate these to malaria infection and haemoglobin levels in lowland and highland areas of differing malaria transmission patterns of Muheza; Tanzania. Blood samples from 1959 individuals aged 6 months to 45 years were collected. A total of 415 (21) and 1181 (60) samples were analysed for G6PD deficiency and HbS; respectively. Malarial parasite prevalence was 17.2(114/1959) in the highlands and 39.6(49/1959) in the lowlands. Lowlands had higher prevalence of G6PD deficiency and HbS than highlands (G6PD deficiency = 11.32(24/212) versus 4.43(9/203); P = 0.01; and HbS = 16.04(98/611) versus 6.32(36/570); P = 0.0001). Logistic regression model showed an association between G6PD deficiency and altitude [lowlands] (Odds ratio [OR] 3.4; 95CI=1.49; 7.90; P=0.004). In the lowlands; G6PD deficient individuals had lower mean haemoglobin (10.9g/dl) than normal ones (12.8g/dl); P = 0.01. These findings show that high malaria transmission in the lowlands might have selected for G6PD deficiency and HbS

Pattern and spatial distribution of plague in Lushoto; north-eastern Tanzania

A review of plague records from 1986 to 2002 and household interviews were carried out in the plague endemic villages to establish a pattern and spatial distribution of the disease in Lushoto district; Tanzania. Spatial data of households and village centres were collected and mapped using a hand held Global Positioning System and Geographical Information System. During the 16-year period; there were 6249 cases of plague of which 5302 (84.8) were bubonic; 391 (6.3)septicaemic; and 438 (7.0) pneumonic forms. A total of 118 (1.9) cases were not categorized. Females and individuals aged 7-18 years old were the most affected groups accounting for 54.4(95CI: 52.4-56.0) and 47.0(95CI: 45- 49) of all reported cases; respectively. Most cases were found in villages at high altitudes (1700-1900m); and there was a decline in case fatality rate (CFR) in areas that experienced frequent outbreaks. Overall; there was a reduction in mean reporting time (from symptoms onset to admission) to an average of 1.35 days (95CI: 1.30-1.40) over the years; although this remained high among adult patients (18 years). Despite the decrease in the number of cases and CFR over the years; our findings indicate that Lushoto district experiences human plague epidemic every year; with areas at high altitudes being more prone to outbreaks. The continued presence of plague in this focus warrants further studies. Nonetheless; our findings provide a platform for development of an epidemic preparedness plan to contain future outbreaks