Human health improvement in Sub-Saharan Africa through integrated management of arthropod transmitted diseases and natural resources

A concept of an ecosystem approach to human health improvement in Sub-Saharan Africa is presented here. Three factors mainly affect the physical condition of the human body: the abiotic environment, vector-transmitted diseases, and natural resources. Our concept relies on ecological principles embedded in a social context and identifies three sets of subsystems for study and management: human disease subsystems, natural resource subsystems, and decision-support subsystems. To control human diseases and to secure food from resource subsystems including livestock or crops, integrated preventive approaches are preferred over exclusively curative and sectorial approaches. Environmental sustainability - the basis for managing matter and water flows - contributes to a healthy human environment and constitutes the basis for social sustainability. For planning and implementation of the human health improvement scheme, participatory decision-support subsystems adapted to the local conditions need to be designed through institutional arrangements. The applicability of this scheme is demonstrated in urban and rural Ethiopia.

Ipsilateral ureteroureterostomy for single ureteral reflux or obstruction in a duplicate system

PURPOSE

The traditional treatment for obstruction or reflux involving a single ureter in a duplicated system has been common sheath reimplantation. More recently, ipsilateral ureteroureterostomy has been suggested as an alternative treatment. We reviewed cases with duplicate systems that were treated with ipsilateral ureteroureterostomy at our institution to determine the acceptability of this operation as an alternative to common sheath reimplantation.

MATERIALS AND METHODS

A total of 22 patients with 24 duplicate systems underwent ipsilateral ureteroureterostomy between March 1986 and December 1996. Patient charts were reviewed and analyzed for patient age, sex, ureteral and renal anatomy, initial presentation, the clinical situation necessitating operation, and the occurrence of early and late complications. Patients were followed for a mean period of 41.4 months.

RESULTS

Two adults and 20 children 10 years old or younger presented with urinary tract infection (13), hydronephrosis on maternal ultrasound (5), dribbling (2), ureteral calculus (1) and hydronephrosis on neonatal abdominal ultrasound (1). Mean hospital stay was 3 days. There was 1 early and 1 late complication.

CONCLUSIONS

Ipsilateral ureteroureterostomy is an acceptable alternative to common sheath reimplantation in select patients with single ureteral disease in a duplicate system.

Livestock grazing and biodiversity: Effects on CO2 exchange in semi-arid Karoo ecosystems, South Africa

Livestock use in semi-arid South African ecosystems has not been extensively studied in relation to the Net Ecosystem Exchange (NEE) of carbon dioxide (CO2). We present four years of measurements from twinned eddy-covariance towers in Nama-Karoo, South Africa, to investigate the carbon fluxes and the impact of grazing intensity on NEE. The design contrasted NEE at a long-term site grazed at recommended levels (LG) with a long-term heavily grazed (EG) site that had been rested for 10 years, and was monitored for two years after which intensive grazing was reintroduced for this experiment. This allowed for the quantification of long-term NEE trends on "recovering" vegetations (years I, II) and short-term responses to an intensified land use (years III, IV). The results showed that the net release of CO2 was slightly higher at LG than on "recovering" vegetation at the EG site, where near-neutral exchange was observed during years I and II. However, after grazing was reintroduced to the EG site, differences between sites was reduced but not eliminated. These findings suggest that there is a somewhat higher carbon sequestration potential at the resting EG site than at the LG site, apparently associated with the dominance of unpalatable drought-tolerant grass species and local elimination of many palatable shrubs. Reduction of this sink potential by reintroduction of high-intensity grazing indicates the sensitivity of C-sequestration in this "recovering" system to heavy grazing, but underlines continued resilience of NEE under far heavier grazing than in the LG system. These data suggest notable trade-offs in these ecosystems between carbon storage, biodiversity, and livestock production with rainfall variability being a critical inter-annual driver. PLAIN LANGUAGE SUMMARY: This study suggests that long-term resting of previously over-utilized southern African semi-arid vegetation supports enhanced carbon sequestration potential, even if over-utilization has transformed vegetation composition (i.e. has caused degradation through reduced plant species richness). However, this enhanced carbon sequestration potential can be quickly negated by the reintroduction of grazing, even after 10 years of resting. Achievement of carbon sequestration is dependent on average to above-average precipitation and its distribution throughout the year, with sink activity evident mainly after seasonal rains during the warm season.