Emerging malaria in pastoralist communities

We are pleased to announce a new grant from the National Institutes of Health to describe the epidemiology of malaria in pastoralist and recently settled communities in northern Kenya. We are particularly interested in the role of human circulation and parasite importation on malaria transmission in these semi-arid regions that are undergoing enormous demographic transitions.

Malaria is declining in many parts of sub-Saharan Africa and numerous countries now consider elimination to be an achievable goal. A major threat to local and national elimination is the re-importation of malaria parasites from malaria-endemic areas which can reignite and even sustain local transmission in zones where it would not occur naturally. Often in these zones, changing climate, land-use, and human settlement patterns further enhance the susceptibility of environments to sustained transmission after parasite importation.

Northern Kenya is a prototypical example of the convergence of changing ecosystem and parasite importation. Historically, large swathes of northern Kenya were considered outside of the malaria risk map. These arid and semi-arid regions are unsuitable for cultivation and are populated by nomadic and semi-nomadic peoples. Recently, these groups are creating more settled, permanent communities than ever before and changing the landscape as a result.

In the far north-west of Kenya around Lake Turkana, this increased pattern of settlement and changing lifestyle can be attributed in large part to oil discovery and the influx of people, money, and infrastructure that accompanies resource extraction. Migrants from all regions of Kenya, east Africa, and beyond have become the new nomads of this region; they work with oil companies, non-governmental organizations, and charities and stay for short periods of time. Prior to the establishment of weekly flights, travel was by a long, arduous land route and the number of visitors was relatively few. Now an estimated 30 flights arrive and depart each week. Many of these visitors originate from malaria-endemic areas as flights connect from western and coastal Kenya to Turkana via Nairobi.

This steady stream of visitors from malaria-endemic zones are importing parasites into an environment of increasing mosquito populations and a non-immune local population, creating ideal conditions for epidemic or possibly emerging endemic transmission of malaria parasites. This setting provides a model for studying parasite importation by a ‘mobile reservoir’ and identifying means by which it may be interrupted.

 Read the post about our first visit here.

 Collaborators on this project: 

  • Andrew Obala – Moi University
  • Amy Wesolowski – Johns Hopkins University
  • Diana Menya – Moi University
  • Steve Taylor – Duke University
  • Samwel Lokemer – Turkana County Health Management Team