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

Risk Factors for Low Birth-Weight in Areas with Varying Malaria Transmission in Korogwe; Tanzania: Implications for Malaria Control

Low birth weight (LBW) is a risk factor for infant mortality; morbidity; growth retardation; poor cognitive development; and chronic diseases. Maternal exposure to diseases such as malaria; HIV; and syphilis has been shown to have a significant impact on birth weight (BW). This study was aimed at determining whether there was a difference in rates of LBW in areas of varying malaria transmission intensity in Korogwe; Tanzania. Retrospective data for one year (June 2004-May 2005) in three maternal and child health (MCH) clinics in the district were analysed. Villages were stratified into three strata: lowlands-semi urban (average altitude of 320m); lowlands-rural (below 600m) and highlands (=600m). There was a significant decreasing trend of rate of LBW from rural lowlands to highlands (X2 trend =7.335; P=0.007). Adjusting for covariates; women in parity-two were at reduced risk of delivering LBW babies compared to first parity women (OR=0.44; 95CI 0.19-0.98; P=0.045). Similarly; the risk of LBW was higher in women who had delayed MCH gestational booking and in women who conceived during high malaria transmission seasons. There was high degree of preference of digits ending with 0/5 in reporting BW in the studied MCHs. In conclusion; a rate of LWB was high in rural lowlands where malaria is also endemic; and was associated with high malaria transmission seasons

Malaria specific mortality in lowlands and highlands of Muheza district; north-eastern Tanzania

Vital registration of causes of death in Tanzania is incomplete and many deaths occur outside health care settings. Verbal autopsies (VA) are used to determine the underlying cause of death, and the probable diagnosis helps to estimate reasonably cause-specific mortality. In this paper, we report findings of a verbal autopsy survey which involved eight villages in both low and highlands of Muheza district, north-eastern Tanzania. The survey was conducted following.a rapid census, which was done to identify households that had lost one or more members within a period of two years from the date of census. Trained research assistants administered VA questionnaires to parents/close relatives. Two physicians reviewed each report independently and a third opinion was sought where there was discordant report between the two. A total of 9,872 households were surveyed and 134 deaths were recorded. A total of 96 (71.6%) deaths were from lowland villages representing high malaria transmission. Majority (72.4%) of the reported deaths occurred at home whilst 32.1% occurred at heath facility settings. Overall, severe malaria was the leading cause accounting for 34.3% of all deaths. Infants were most affected and accounted for 43.5% of the total deaths. Pulmonary tuberculosis ranked second (8.2%) cause of deaths and was exclusively confined to individuals ≥15 years. Probable cause of death could not be determined in 13.4% of deaths. In conclusion, majority of deaths in rural north-eastern Tanzania occur at home and the immediate causes are usually unknown or not documented. These findings indicate that the verbal autopsy is a useful tool for detecting leading causes of death at community level in the absence of health facility-based data

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

Malaria Presumtive Treatment in Tanzania : is it a Rational Approach for Malaria Management in Rural Health Units?

Against imperfect performance of presumptive treatment strategy in malaria management in most endemic areas with perennial and seasonal transmission; its potential benefits have not been adequately evaluated in areas with low malaria transmission. We assessed the rationality of presumptive treatment in 688 Tanzanian children attended at the Amani government rural dispensary; northeast Tanzania; an area with low malaria transmission form April to December 1993. A total of 549 (80)) children were clinically diagnosed by the attending clinical officer and managed as malaria cases. Among these; 216 (39) children were misdiagnosed based on the diagnosis criteria 1(DC1) of reported or history of fever plus asexual Plasmodium falciparum density at any level. At cut-off point of reported or history of fever; axillary temperature of 37.5 degrees Centigrade or above plus asexual P. falciparum density of either /=40 per microL (DC2) or /=5000 per microL (DC3) of blood; 380 (67) and 484 (88) children were respectively erroneously diagnosed. The level of misdiagnosis increased with age and was significantly higher during the dry season. These findings suggests that in Amani an area with low malaria transmission; presumptive treatment based on reported or history fever was less effective resulting into a substantial proportion of children being inappropriately managed. However; in the absence of sensitive; simple and affordable diagnostic devices in rural health units; we consider that effective use of thermometers and consideration of alternative diagnosis among feverish children might minimise the magnitude of unwarranted malaria treatment