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Co-infections determine patterns of mortality in a population exposed to parasite infection

Woolhouse, Mark E.J.; Thumbi, Samuel M.; Jennings, Amy; Chase-Topping, Margo; Callaby, Rebecca; Kiara, Henry; Oosthuizen, Marinda C.; Mbole-Kariuki, Mary N.; Conradie, Ilana; Handel, Ian G.; Poole, E. Jane; Njiiri, Evalyne; Collins, Nicola E.; Murray, Gemma; Tapio, Miika; Auguet, Olga Tosas; Weir, Willie; Morrison, W. Ivan; Kruuk, Loeske E.B.; De Bronsvoort, C. B.Mark; Hanotte, Olivier; Coetzer, Koos; Toye, Philip G.

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Mark E.J. Woolhouse

Samuel M. Thumbi

Amy Jennings

Margo Chase-Topping

Rebecca Callaby

Henry Kiara

Marinda C. Oosthuizen

Mary N. Mbole-Kariuki

Ilana Conradie

Ian G. Handel

E. Jane Poole

Evalyne Njiiri

Nicola E. Collins

Gemma Murray

Miika Tapio

Olga Tosas Auguet

Willie Weir

W. Ivan Morrison

Loeske E.B. Kruuk

C. B.Mark De Bronsvoort

Director of Frozen Ark Project & Professor of Genetics & Conservation

Koos Coetzer

Philip G. Toye


© 2015 The Authors, some rights reserved. Many individual hosts are infected with multiple parasite species, and this may increase or decrease the pathogenicity of the infections. This phenomenon is termed heterologous reactivity and is potentially an important determinant of both patterns ofmorbidity andmortality and of the impact of disease controlmeasures at the population level. Using infections with Theileria parva (a tick-borne protozoan, related to Plasmodium) in indigenous African cattle [where it causes East Coast fever (ECF)] as a model system, we obtain the first quantitative estimate of the effects of heterologous reactivity for any parasitic disease. In individual calves, concurrent co-infection with less pathogenic species of Theileria resulted in an 89% reduction inmortality associated with T. parva infection. Across our study population, this corresponds to a net reduction in mortality due to ECF of greater than 40%. Using a mathematical model, we demonstrate that this degree of heterologous protection provides a unifying explanation for apparently disparate epidemiological patterns: variable disease-inducedmortality rates, age-mortality profiles, weak correlations between the incidence of infection and disease (known as endemic stability), and poor efficacy of interventions that reduce exposure to multiple parasite species. These findings can be generalized to many other infectious diseases, including human malaria, and illustrate how co-infections can play a key role in determining population-level patterns of morbidity and mortality due to parasite infections.


Woolhouse, M. E., Thumbi, S. M., Jennings, A., Chase-Topping, M., Callaby, R., Kiara, H., …Toye, P. G. (2015). Co-infections determine patterns of mortality in a population exposed to parasite infection. Science Advances, 1(2), Article e1400026.

Journal Article Type Article
Acceptance Date Feb 11, 2015
Online Publication Date Mar 20, 2015
Publication Date Mar 1, 2015
Deposit Date Feb 5, 2021
Publicly Available Date Feb 5, 2021
Journal Science Advances
Electronic ISSN 2375-2548
Publisher American Association for the Advancement of Science
Peer Reviewed Peer Reviewed
Volume 1
Issue 2
Article Number e1400026
Public URL
Publisher URL


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