Ethical, legal and social aspects of the approach in Sudan

The global malaria situation, especially in Africa, and the problems frequently encountered in chemical control of vectors such as insecticide resistance, emphasize the urgency of research, development and implementation of new vector control technologies that are applicable at regional and local levels. The successful application of the sterile insect technique (SIT) for the control of the New World screwworm Cochliomyia hominivorax and several species of fruit flies has given impetus to the use of this method for suppression or elimination of malaria vectors in some areas of Africa including Northern State of Sudan. The research and development phase of the Northern State feasibility study has been started. Sudanese stakeholders are working side-by-side with the International Atomic Energy Agency in the activities of this important phase. Several ethical, legal and social issues associated with this approach arose during this phase of the project. They need to be seriously considered and handled with care. In this paper, these issues are described, and the current and proposed activities to overcome potential hurdles to ensure success of the project are listed

Field site selection: getting it right first time around

The selection of suitable field sites for integrated control of Anopheles mosquitoes using the sterile insect technique (SIT) requires consideration of the full gamut of factors facing most proposed control strategies, but four criteria identify an ideal site: 1) a single malaria vector, 2) an unstructured, relatively low density target population, 3) isolation of the target population and 4) actual or potential malaria incidence. Such a site can exist in a diverse range of situations or can be created. Two contrasting SIT field sites are examined here: the desert-flanked Dongola Reach of the Nile River in Northern State, Sudan, where malaria is endemic, and the island of La Reunion, where autochthonous malaria is rare but risk is persistent. The single malaria-transmitting vector at both sites is Anopheles arabiensis. In Sudan, the target area is a narrow 500 km corridor stretching from the rocky terrain at the Fourth Cataract - just above the new Merowe Dam, to the northernmost edge of the species range, close to Egypt. Vector distribution and temporal changes in density depend on the Nile level, ambient temperature and human activities. On La Reunion, the An. arabiensis population is coastal, limited and divided into three areas by altitude and exposure to the trade winds on the east coast. Mosquito vectors for other diseases are an issue at both sites, but of primary importance on La Reunion due to the recent chikungunya epidemic. The similarities and differences between these two sites in terms of suitability are discussed in the context of area-wide integrated vector management incorporating the SIT

Map of Khartoum state showing the distribution of survey locations.

<p>A total of 256 <i>P. falciparum</i> prevalence surveys were undertaken in 203 locations (some survey locations were repeated in subsequent years) from 1999–2008. Inset is the state map of the Sudan showing the location of Khartoum state.</p

Summary of Khartoum <i>P. falciparum</i> prevalence data from 256 surveys in 203 locations (some survey locations were repeated in subsequent years) from 1999 to 2008 showing annual average infection prevalence and the percentage and number of survey locations with no positive cases by year.

<p>Summary of Khartoum <i>P. falciparum</i> prevalence data from 256 surveys in 203 locations (some survey locations were repeated in subsequent years) from 1999 to 2008 showing annual average infection prevalence and the percentage and number of survey locations with no positive cases by year.</p

Location of primary spatial clusters of <i>P. falciparum</i> prevalence.

<p>Primary spatial clusters in Khartoum state in each year from 1999 to 2008 are shown as pink circles of varying radius or red zeros (when a cluster radius is indeterminate). The primary spatial clusters in 2001, 2002, 2004 and 2008 were all statistically not significant (Kulldorff scan statistic of >0.05). Years with statistically significant spatial clusters are shaded grey.</p

Graph of <i>P. falciparum</i> prevalence (solid line) and the total annual rainfall (bars) in Khartoum state by year of survey from 1999–2008.

<p>Graph of <i>P. falciparum</i> prevalence (solid line) and the total annual rainfall (bars) in Khartoum state by year of survey from 1999–2008.</p

Primary spatial only <i>P. falciparum</i> clusters, their radius, the number of survey locations and cases contained in the clusters and the significance of the Kulldorff scan statistic in Khartoum state from 1999 to 2008.

<p>Primary spatial only <i>P. falciparum</i> clusters, their radius, the number of survey locations and cases contained in the clusters and the significance of the Kulldorff scan statistic in Khartoum state from 1999 to 2008.</p