Graphic illustrating malaria in Africa

The numbers game

Maths can be a key weapon in the war against infectious disease

The spread of an infectious disease is a complex affair, affected by many factors. Mathematical equations modelling the spread of disease can help us limit the impact of future infections.

These mathematical models can be used to simulate or re-run outbreaks and to test the impact of different control strategies. In late 2014, for instance, Canadian scientists predicted using a mathematical model that 700,000 people will have been infected in the West African Ebola epidemic by 2016. Meanwhile, a US team calculated the number of new cases that could be prevented by isolating a certain proportion of infected people.

Data from drug trials have been fed into mathematical models to test the effects of combined therapies for malaria. In 2014 Dutch and UK researchers working with mathematical models predicted that adding the drug ivermectin to standard artemisinin-based treatments would kill more of the malaria-carrying parasites and reduce transmission.

Mathematical models of pandemic flu have also produced some useful predictions: border and travel restrictions may delay but won’t prevent an outbreak; closing schools will cut the peak attack rate in half, but isolating the infected will have a bigger impact; and vaccines will help even if they are only partially effective.

However, the models make a number of assumptions about the nature of infection, so are inevitably simplifications. The main problem is that key information – how the disease spreads, how long it survives in the environment – may not be available.

Lead image:

Modelling can help with malaria in Africa, and with other infectious diseases too.

AJC1/Flickr CC BY NC

References

Further reading

About this resource

This resource was first published in ‘Epidemics’ in September 2007 and reviewed and updated in January 2015.

Topics:
Statistics and maths, Ecology and environment, Health, infection and disease, Medicine, Immunology
Issue:
Epidemics
Education levels:
16–19, Continuing professional development