Skip to main content
    • Aa
    • Aa
  • Get access
    Check if you have access via personal or institutional login
  • Cited by 26
  • Cited by
    This article has been cited by the following publications. This list is generated based on data provided by CrossRef.

    Turner, Joanne Howell, Alison McCann, Cathy Caminade, Cyril Bowers, Roger G. Williams, Diana and Baylis, Matthew 2016. A model to assess the efficacy of vaccines for control of liver fluke infection. Scientific Reports, Vol. 6, p. 23345.

    Gambhir, Manoj Singh, Brajendra K. and Michael, Edwin 2015. Mathematical Models for Neglected Tropical Diseases: Essential Tools for Control and Elimination, Part A.

    Gethings, O.J. Sage, R.B and Leather, S.R 2015. Spatial distribution of infectious stages of the nematode Syngamus trachea within pheasant (Phasianus colchicus) release pens on estates in the South West of England: Potential density dependence?. Veterinary Parasitology, Vol. 212, Issue. 3-4, p. 267.

    Lagrue, Clément and Poulin, Robert 2015. Bottom-up regulation of parasite population densities in freshwater ecosystems. Oikos, Vol. 124, Issue. 12, p. 1639.

    Smith, Anya F Semeniuk, Christina AD Kutz, Susan J and Massolo, Alessandro 2014. Dog-walking behaviours affect gastrointestinal parasitism in park-attending dogs. Parasites & Vectors, Vol. 7, Issue. 1, p. 429.

    Turner, Hugo C. Walker, Martin French, Michael D. Blake, Isobel M. Churcher, Thomas S. and Basáñez, María-Gloria 2014. Neglected tools for neglected diseases: mathematical models in economic evaluations. Trends in Parasitology, Vol. 30, Issue. 12, p. 562.

    Hing, S Othman, N Nathan, SKSS Fox, M Fisher, M and Goossens, B 2013. First parasitological survey of Endangered Bornean elephants Elephas maximus borneensis. Endangered Species Research, Vol. 21, Issue. 3, p. 223.

    Walker, Martin Hall, Andrew and Basáñez, María-Gloria 2013. Ascaris: The Neglected Parasite.

    Wan, Cheng Liu, Yun Tu, Xiao-Ming Zhang, Yuan-Yuan Xu, Jin-Mei Lin, Dan-Dan Luo, Jian-Ping Chen, Feng and Wu, Hai-Wei 2013. A cellular automaton model of Schistosoma japonicum infection. Acta Tropica, Vol. 126, Issue. 3, p. 256.

    Basáñez, María-Gloria French, Michael D. Walker, Martin and Churcher, Thomas S. 2012. Paradigm lost: how parasite control may alter pattern and process in human helminthiases. Trends in Parasitology, Vol. 28, Issue. 4, p. 161.

    Fox, Naomi J. Marion, Glenn Davidson, Ross S. White, Piran C. L. and Hutchings, Michael R. 2012. Livestock Helminths in a Changing Climate: Approaches and Restrictions to Meaningful Predictions. Animals, Vol. 2, Issue. 4, p. 93.

    Stephen Phillips, R 2012. eLS.

    Durban, Jordi Juárez, Paula Angulo, Yamileth Lomonte, Bruno Flores-Diaz, Marietta Alape-Girón, Alberto Sasa, Mahmood Sanz, Libia Gutiérrez, José M Dopazo, Joaquín Conesa, Ana and Calvete, Juan J 2011. Profiling the venom gland transcriptomes of Costa Rican snakes by 454 pyrosequencing. BMC Genomics, Vol. 12, Issue. 1, p. 259.

    Rodríguez-Pérez, Mario A. Unnasch, Thomas R. and Real-Najarro, Olga 2011. Advances in Parasitology Volume 77.

    Basáñez, María‐Gloria Churcher, Thomas S. and Grillet, María‐Eugenia 2009. Natural History of Host-Parasite Interactions.

    Stafford, K.A. Morgan, E.R. and Coles, G.C. 2009. Weight-based targeted selective treatment of gastrointestinal nematodes in a commercial sheep flock. Veterinary Parasitology, Vol. 164, Issue. 1, p. 59.

    Basáñez, María-Gloria Pion, Sébastien DS Boakes, Eve Filipe, João AN Churcher, Thomas S and Boussinesq, Michel 2008. Effect of single-dose ivermectin on Onchocerca volvulus: a systematic review and meta-analysis. The Lancet Infectious Diseases, Vol. 8, Issue. 5, p. 310.

    Churcher, Thomas S. and Basáñez, María-Gloria 2008. DENSITY DEPENDENCE AND THE SPREAD OF ANTHELMINTIC RESISTANCE. Evolution, Vol. 62, Issue. 3, p. 528.

    Grillet, María-Eugenia Villamizar, Nestor J. Frontado, Hortencia L. Cortez, José Escalona, Marisela Botto, Carlos and Basáñez, María-Gloria 2008. Vector competence of Simulium oyapockense s.l. and S. incrustatum for Onchocerca volvulus: Implications for ivermectin-based control in the Amazonian focus of human onchocerciasis, a multi-vector–host system. Acta Tropica, Vol. 107, Issue. 2, p. 80.

    Honarvar, Shaya O’Connor, Michael P. and Spotila, James R. 2008. Density-dependent effects on hatching success of the olive ridley turtle, Lepidochelys olivacea. Oecologia, Vol. 157, Issue. 2, p. 221.


Density dependence and overdispersion in the transmission of helminth parasites

  • T. S. CHURCHER (a1), N. M. FERGUSON (a1) and M.-G. BASÁÑEZ (a1)
  • DOI:
  • Published online: 01 March 2005

The influence of density-dependent processes on the transmission of parasitic helminths is determined by both the severity of the regulatory constraints and the degree of parasite overdispersion among the host population. We investigate how overdispersed parasite distributions among humans influence transmission levels in both directly- and indirectly-transmitted nematodes (Ascaris lumbricoides and Onchocerca volvulus). While past work has assumed, for simplicity, that density dependence acts on the average worm load, here we model density-dependence as acting on individual parasite burdens before averaging across hosts. A composite parameter, which we call the effective transmission contribution, is devised to measure the number of transmission stages contributed by a given worm burden after incorporating overdispersion in adult worm mating probabilities and other density-dependent mechanisms. Results indicate that the more overdispersed the parasite population, the greater the effect of density dependence upon its transmission dynamics. Strong regulation and parasite overdispersion make the relationship between mean worm burden and its effective contribution to transmission highly non-linear. Consequently, lowering the intensity of infection in a host population using chemotherapy may produce only a small decline in transmission (relative to its initial endemic level). Our analysis indicates that when parasite burden is low, intermediate levels of parasite clustering maximize transmission. Implications are discussed in relation to existing control programmes and the spread of anthelmintic resistance.

Corresponding author
Tel: +44 (0) 20 75943229. Fax: +44 (0)20 74023927. E-mail:
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

  • ISSN: 0031-1820
  • EISSN: 1469-8161
  • URL: /core/journals/parasitology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *