Modelling Trypanosoma congolense parasitaemia patterns during the chronic phase of infection in N'Dama cattle

Z. Agur, R. Mehr

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We reanalysed parasitaemia profiles of the trypanotolerant N'Dama cattle (Bos taurus), consecutively infected with the same four clones of Trypanosoma congolense. Our analysis shows that each individual parasitaemia is characterized by progressively longer intervals between parasites waves. This pattern is most visible during the chronic phase of infection. In addition, the last of the four infections had a significantly larger overall duration of inter-wave intervals. We retrieved these patterns by numerical simulations of a mathematical model, which incorporates assumptions about the molecular basis of antigenic variation and about the anti-parasitic major immune processes. Six potential factors that may determine parasitaemia pattern were studied: carrying capacity of the host environment, intrinsic growth rate of the parasite, affinity maturation of the immune response, immune cell birth and death rate, levels of antibodies to variant surface glycoprotein and levels of antibodies to invariant antigens. Our simulations suggest that the first five factors are not likely to determine the chronic phase parasitaemia pattern whereas the sixth one, namely, antibody response to invariant antigens, yielded profiles consistent with the experimental data. Being cumulative, the immune response to anti-invariant antigens may be increasingly effective as infection proceeds and in successive infections. Comparisons between N'Dama and Zebu and between chronic and acute phases will be needed to make a statement on the role of this phenomenon in trypanotolerance.

Original languageEnglish
Pages (from-to)171-182
Number of pages12
JournalParasite Immunology
Volume19
Issue number4
DOIs
StatePublished - Apr 1997
Externally publishedYes

Keywords

  • Antibody response
  • Carrying capacity
  • Growth rate
  • Invariant antigen
  • Mathematical model
  • Trypanosoma congolense
  • Trypanotolerance

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