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Depinay, Jean Marc O.; Mbogo, Charles M.; Killeen, Gerry F.; Knols, Bart G. J.; Beier, John C.; Carlson, John C.; Dushoff, Jonathan; Billingsley, Peter F.; Mwambi, Henry; Githure, John I.; Touré, Abdoulaye; McKenzie, F. Ellis

doi:10.1186/1475-2875-3-29

Cited by 161 publications

(117 citation statements)

References 20 publications

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“…Temperature can affect the development of the immature stages of mosquito growth (egg, larva, pupae). Among the dependencies on temperature, the virus incubation period for mosquitoes tends to decrease with increases in temperature (up to a point) [44] and the mosquito life span is longer in temperate regions compared to very hot or cold regions [11,30]. We are modeling an African region close to the equator with nearly constant temperature and daylight so rainfall is the dominant environmental forcing term for our model (as in Schaeffer et al [39]).…”

Section: Resultsmentioning

confidence: 99%

Coupling Vector-host Dynamics with Weather Geography and Mitigation Measures to Model Rift Valley Fever in Africa

McMahon

Manore

Hyman

et al. 2014

Math. Model. Nat. Phenom.

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We present and characterize a multi-host epidemic model of Rift Valley fever (RVF) virus in East Africa with geographic spread on a network, rule-based mitigation measures, and mosquito infection and population dynamics. Susceptible populations are depleted by disease and vaccination and are replenished with the birth of new animals. We observe that the severity of the epidemics is strongly correlated with the duration of the rainy season and that even severe epidemics are abruptly terminated when the rain stops. Because naturally acquired herd immunity is established, total mortality across 25 years is relatively insensitive to many mitigation approaches. Strong reductions in cattle mortality are expected, however, with sufficient reduction in population densities of either vectors or susceptible (ie. unvaccinated) hosts. A better understanding of RVF epidemiology would result from serology surveys to quantify the importance of herd immunity in epidemic control, and sequencing of virus from representative animals to quantify the realative importance of transportation and local reservoirs in nucleating yearly epidemics. Our results suggest that an effective multi-layered mitigation strategy would include vector control, movement control, and vaccination of young animals yearly, even in the absence of expected rainfall.

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Section: Resultsmentioning

confidence: 99%

Coupling Vector-host Dynamics with Weather Geography and Mitigation Measures to Model Rift Valley Fever in Africa

McMahon

Manore

Hyman

et al. 2014

Math. Model. Nat. Phenom.

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“…Although models that explicitly incorporate juvenile mosquito stages have been studied (Hancock & Godfray 2007), their further development is hampered by a lack of understanding of how density dependence operates in the larval stage (Lyimo et al 1992;Gimnig et al 2002;Ahumada et al 2004) and how to incorporate the effect of climate and spatial processes on juvenile lifehistory variables (Rosenberg et al 1990;Gimnig et al 2002;Gu et al 2003;Depinay et al 2004;. Entomopathogens can lower adult fecundity (Scholte et al 2005) and may thus affect adult mosquito densities via recruitment as well as mortality.…”

Section: Discussionmentioning

confidence: 99%

An age-structured model to evaluate the potential of novel malaria-control interventions: a case study of fungal biopesticide sprays

2008

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It has recently been proposed that mosquito vectors of human diseases, particularly malaria, may be controlled by spraying with fungal biopesticides that increase the rate of adult mortality. Though fungal pathogens do not cause instantaneous mortality, they can kill mosquitoes before they are old enough to transmit disease. A model is developed (i) to explore the potential for fungal entomopathogens to reduce significantly infectious mosquito populations, (ii) to assess the relative value of the many different fungal strains that might be used, and (iii) to help guide the tactical design of vector-control programmes. The model follows the dynamics of different classes of adult mosquitoes with the risk of mortality due to the fungus being assumed to be a function of time since infection (modelled using the Weibull distribution). It is shown that substantial reductions in mosquito numbers are feasible for realistic assumptions about mosquito, fungus and malaria biology and moderate to low daily fungal infection probability. The choice of optimal fungal strain and spraying regime is shown to depend on local mosquito and malaria biology. Fungal pathogens may also influence the ability of mosquitoes to transmit malaria and such effects are shown to further reduce vectorial capacity.

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“…Rainfall increases the number and sizes of breeding sites, leading to an increase in the survival of juvenile stages of mosquitoes, a corresponding increase in the emergence rate of new adults, and a higher egg-laying rate and host-seeking behaviour in adults [20,36]. Higher temperatures decrease the incubation period of the virus in mosquitoes [5,37], while very high or very low temperatures increase the mortality rate of mosquitoes [13,24]. …”

Section: Introductionmentioning

confidence: 99%

Modelling vertical transmission in vector-borne diseases with applications to Rift Valley fever

Chitnis

Hyman

Manore

2013

Journal of Biological Dynamics

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We present two ordinary differential equation models for Rift Valley fever (RVF) transmission in cattle and mosquitoes. We extend existing models for vector-borne diseases to include an asymptomatic host class and vertical transmission in vectors. We define the basic reproductive number, , and analyse the existence and stability of equilibrium points. We compute sensitivity indices of and a reactivity index (that measures epidemicity) to parameters for baseline wet and dry season values. is most sensitive to the mosquito biting and death rates. The reactivity index is most sensitive to the mosquito biting rate and the infectivity of hosts to vectors. Numerical simulations show that even with low equilibrium prevalence, increases in mosquito densities through higher rainfall, in the presence of vertical transmission, can result in large epidemics. This suggests that vertical transmission is an important factor in the size and persistence of RVF epidemics.

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Untitled

Cited by 161 publications

References 20 publications

Coupling Vector-host Dynamics with Weather Geography and Mitigation Measures to Model Rift Valley Fever in Africa

Coupling Vector-host Dynamics with Weather Geography and Mitigation Measures to Model Rift Valley Fever in Africa

An age-structured model to evaluate the potential of novel malaria-control interventions: a case study of fungal biopesticide sprays

Modelling vertical transmission in vector-borne diseases with applications to Rift Valley fever

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