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Linking immunological and epidemiological dynamics of HIV: the case of super-infection.

Martcheva M, Li XZ - J Biol Dyn (2013)

Bottom Line: The immunological reproduction numbers, the epidemiological reproduction numbers and invasion reproduction numbers are computed.The single-strain population-level equilibria are locally asymptotically stable suggesting that in the absence of superinfection oscillations do not occur, a result contrasting previous studies of HIV age-since-infection structured models.Simulations suggest that the epidemiological reproduction number and HIV population prevalence are monotone functions of the within-host parameters with reciprocal trends.

View Article: PubMed Central - PubMed

Affiliation: Department of Mathematics, University of Florida, 358 Little Hall, PO Box 118105, Gainesville, FL 32611-8105, USA. maia@math.ufl.edu

ABSTRACT
In this paper, a two-strain model that links immunological and epidemiological dynamics across scales is formulated. On the within-host scale, the two strains eliminate each other with the strain with the larger immunological reproduction persisting. However, on the population scale superinfection is possible, with the strain with larger immunological reproduction number super-infecting the strain with the smaller immunological reproduction number. The two models are linked through the age-since-infection structure of the epidemiological variables. In addition, the between-host transmission and the disease-induced death rate depend on the within-host viral load. The immunological reproduction numbers, the epidemiological reproduction numbers and invasion reproduction numbers are computed. Besides the disease-free equilibrium, there are two population-level strain one and strain two isolated equilibria, as well as a population-level coexistence equilibrium when both invasion reproduction numbers are greater than one. The single-strain population-level equilibria are locally asymptotically stable suggesting that in the absence of superinfection oscillations do not occur, a result contrasting previous studies of HIV age-since-infection structured models. Simulations suggest that the epidemiological reproduction number and HIV population prevalence are monotone functions of the within-host parameters with reciprocal trends. In particular, HIV medications that decrease within-host viral load also increase overall population prevalence. The effect of the immunological parameters on the population reproduction number and prevalence is more pronounced when the initial viral load is lower.

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Related in: MedlinePlus

Epidemiological reproduction number vs. the shedding rate.
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Related In: Results  -  Collection

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Figure 2: Epidemiological reproduction number vs. the shedding rate.

Mentions: The epidemiological reproduction number is much more sensitive to the epidemiological parameters. It increases when the shedding rate increases and does so almost linearly, without an upper bound (Figure 2). ℛ0 increases with s and decreases with m0 and m1. Figure 2 shows that as a function of s, the epidemiological reproduction number does not depend on the virus initial amount V0.


Linking immunological and epidemiological dynamics of HIV: the case of super-infection.

Martcheva M, Li XZ - J Biol Dyn (2013)

Epidemiological reproduction number vs. the shedding rate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3756640&req=5

Figure 2: Epidemiological reproduction number vs. the shedding rate.
Mentions: The epidemiological reproduction number is much more sensitive to the epidemiological parameters. It increases when the shedding rate increases and does so almost linearly, without an upper bound (Figure 2). ℛ0 increases with s and decreases with m0 and m1. Figure 2 shows that as a function of s, the epidemiological reproduction number does not depend on the virus initial amount V0.

Bottom Line: The immunological reproduction numbers, the epidemiological reproduction numbers and invasion reproduction numbers are computed.The single-strain population-level equilibria are locally asymptotically stable suggesting that in the absence of superinfection oscillations do not occur, a result contrasting previous studies of HIV age-since-infection structured models.Simulations suggest that the epidemiological reproduction number and HIV population prevalence are monotone functions of the within-host parameters with reciprocal trends.

View Article: PubMed Central - PubMed

Affiliation: Department of Mathematics, University of Florida, 358 Little Hall, PO Box 118105, Gainesville, FL 32611-8105, USA. maia@math.ufl.edu

ABSTRACT
In this paper, a two-strain model that links immunological and epidemiological dynamics across scales is formulated. On the within-host scale, the two strains eliminate each other with the strain with the larger immunological reproduction persisting. However, on the population scale superinfection is possible, with the strain with larger immunological reproduction number super-infecting the strain with the smaller immunological reproduction number. The two models are linked through the age-since-infection structure of the epidemiological variables. In addition, the between-host transmission and the disease-induced death rate depend on the within-host viral load. The immunological reproduction numbers, the epidemiological reproduction numbers and invasion reproduction numbers are computed. Besides the disease-free equilibrium, there are two population-level strain one and strain two isolated equilibria, as well as a population-level coexistence equilibrium when both invasion reproduction numbers are greater than one. The single-strain population-level equilibria are locally asymptotically stable suggesting that in the absence of superinfection oscillations do not occur, a result contrasting previous studies of HIV age-since-infection structured models. Simulations suggest that the epidemiological reproduction number and HIV population prevalence are monotone functions of the within-host parameters with reciprocal trends. In particular, HIV medications that decrease within-host viral load also increase overall population prevalence. The effect of the immunological parameters on the population reproduction number and prevalence is more pronounced when the initial viral load is lower.

Show MeSH
Related in: MedlinePlus