A time-periodic and reaction–diffusion Dengue fever model with extrinsic incubation period and crowding effects

2020 ◽  
Vol 51 ◽  
pp. 102988 ◽  
Author(s):  
Liang Zhang ◽  
Shuang-Ming Wang
Keyword(s):  
Dengue Fever ◽  
Incubation Period ◽  
Reaction Diffusion ◽  
Crowding Effects ◽  
Extrinsic Incubation Period ◽  
Time Periodic

Vector survival and parasite infection: the effect of Wuchereria bancrofti on its vector Culex quinquefasciatus

Parasitology ◽  
2004 ◽  
Vol 129 (1) ◽  
pp. 43-50 ◽  
Author(s):  
K. KRISHNAMOORTHY ◽  
S. SUBRAMANIAN ◽  
G. J. VAN OORTMARSSEN ◽  
J. D. F. HABBEMA ◽  
P. K. DAS
Keyword(s):  
Incubation Period ◽  
Culex Quinquefasciatus ◽  
Geometric Mean ◽  
Wuchereria Bancrofti ◽  
Parasite Load ◽  
Infected Mosquito ◽  
Parasite Development ◽  
Mosquito Vector ◽  
Extrinsic Incubation Period ◽  
Parasite Loss

This paper investigates a cohort of 2187 laboratory reared Culex quinquefasciatus fed on 69 human volunteers, including 59 persons with different levels of Wuchereria bancrofti microfilariae and 10 without microfilaria. Mosquitoes were followed until death. Mosquito survival was analysed in relation to the level of microfilaria in the human and larval count in the dead mosquito. Vector mortality during the extrinsic incubation period (12 days post-engorgement) was significantly higher in mosquitoes fed on microfilaraemic volunteers (50%) than in those fed on amicrofilaraemics (29%). Both the percentage infected and the geometric mean parasite density was significantly higher among mosquitoes which died before 13 days (45% infected and 10 larvae per infected mosquito) than those surviving beyond 13 days (39% and 2·2), suggesting a parasite loss of more than 80% during the extrinsic incubation period. A large proportion (62%) of the mosquitoes that died during the early of phase of parasite development were infected (36% in low, 26% in medium and 90% in high human Mf-density). Survival analysis showed that the parasite load in mosquitoes and the human Mf-density for a given parasite load are independent risk factors of vector survival. Overall, the hazard of dying was found to be 11–15 times higher among mosquitoes fed on microfilaraemic volunteers than those fed on amicrofilaraemics. The hazard doubles for every increase of about 60–70 parasites in the vector. As a consequence of the parasite-induced reduction in vector survival, the transmission success of the parasite is reduced. The implication of the results on control/elimination of lymphatic filariasis using mass-drug administration is discussed.

A reaction–diffusion epidemic model with incubation period in almost periodic environments

2020 ◽  
pp. 1-24
Author(s):  
LIZHONG QIANG ◽  
BIN-GUO WANG ◽  
ZHI-CHENG WANG
Keyword(s):  
Time Delay ◽  
Spatial Heterogeneity ◽  
Incubation Period ◽  
Epidemic Model ◽  
Reaction Diffusion ◽  
Fixed Time ◽  
Reaction Diffusion Equations ◽  
Threshold Dynamics ◽  
Almost Periodic ◽  
Periodic Reaction

In this paper, we propose and study an almost periodic reaction–diffusion epidemic model in which disease latency, spatial heterogeneity and general seasonal fluctuations are incorporated. The model is given by a spatially nonlocal reaction–diffusion system with a fixed time delay. We first characterise the upper Lyapunov exponent $${\lambda ^*}$$ for a class of almost periodic reaction–diffusion equations with a fixed time delay and provide a numerical method to compute it. On this basis, the global threshold dynamics of this model is established in terms of $${\lambda ^*}$$ . It is shown that the disease-free almost periodic solution is globally attractive if $${\lambda ^*} < 0$$ , while the disease is persistent if $${\lambda ^*} < 0$$ . By virtue of numerical simulations, we investigate the effects of diffusion rate, incubation period and spatial heterogeneity on disease transmission.

scholarly journals Impact of temperature on the extrinsic incubation period of Zika virus in Aedes aegypti

2020 ◽  
Vol 14 (3) ◽  
pp. e0008047 ◽  
Author(s):  
Olivia C. Winokur ◽  
Bradley J. Main ◽  
Jay Nicholson ◽  
Christopher M. Barker
Keyword(s):  
Aedes Aegypti ◽  
Incubation Period ◽  
Zika Virus ◽  
Extrinsic Incubation Period
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