Mapping infectious diseases in Africa
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* Christopher Mason

*   © 2008 Canadian Medical Association

Mathematical modeling, by predicting the trajectory of infection, can become the next tool experts use to tackle infectious diseases that persist despite decades of effort to contain them, according to Canadian and African researchers attending a recent mathematical epidemiology conference in Kampala, Uganda.

The researchers hope their joint efforts to bridge mathematics and science will yield useful models that help policy-makers decide when and how to deploy resources (Figure 1).

![Figure1](http://www.cmaj.ca/https://www.cmaj.ca/content/cmaj/178/2/137/F1.medium.gif)

[Figure1](http://www.cmaj.ca/content/178/2/137/F1)

**Figure 1:** Researchers say that infectious diseases can be curbed through using of mathematical models demonstrating the correlation between infection rates, resource allocation and a disease's behaviours.

“Many diseases, such as malaria, have cyclical behaviour,” explains Arvind Gupta, scientific director at British Columbia–based Mathematics of Information Technology and Complex Systems, which organized the meeting. “But often resources are needed at their most when malaria rates are at their lowest.”

Often, when an infectious disease is most prevalent, it also has its lowest rate of new infections because the affected population is educated about the disease and resources are deployed. “It's when a disease dips that resources disappear and complacency sets in,” Gupta says.

Modelling, or mathematical epidemiology, is meant to combat that tendency by showing policy-makers the correlation between infection rates, resource allocation and a disease's behaviour.

By doing that, researchers hope to avoid the wild fluctuations that often persist in infection rates, and instead focus on keeping the “R” value (rate of infection) at less than 1 at all times, meaning less than 1 person is infected with the disease for every 1 person who has it. If that can be accomplished, the disease begins a slow but steady march towards being eliminated.

Conference participants, who say that policy-makers do not fully recognize the role mathematical models can play in disease prevention, were optimistic that the groundwork has been laid for future collaborations that tap Canadian expertise in mathematical epidemiology and first–hand African knowledge of disease patterns.

“There are very good scientists here doing work in a resource-poor setting,” says Abba Gumel, director of the University of Manitoba's Institute of Industrial Mathematics. “They don't have access to the resources we do in Canada. But we see that as a chance to build some real collaborations here because these are scientists who know the lay of the land and who to work with.”