Impact of Climate and Mosquito Vector Abundance on Sylvatic Arbovirus Circulation Dynamics in Senegal

Althouse, Benjamin M.; Hanley, Kathryn A.; Diallo, Mawlouth; Sall, Amadou Alpha; Bâ, Yamar; Faye, Ousmane; Diallo, Diawo; Watts, Douglas M.; Weaver, Scott C.; Cummings, Derek A. T.

doi:10.4269/ajtmh.13-0617

Cited by 82 publications

(84 citation statements)

References 36 publications

(46 reference statements)

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“…Phylogenetic analysis indicates that the virus has been introduced into West Africa at least twice in the twentieth century [48] and that West Africa contains ZIKV strains that are distinct from those elsewhere in Africa [49]. Analyses of mosquitoes collected annually over the last fifty years in Kedougou, Senegal demonstrated that ZIKV is amplified in mosquito collections at approximately four year intervals, that rainfall is a positive predictor of ZIKV isolations in mosquitoes, and that there was little positive or negative association between amplification of ZIKV and of three other Aedes -borne arboviruses that circulate in the region, YFV, DENV-2 and CHIKV [50]. Moreover our field studies in Kedougou during the 2011 ZIKV amplification showed that the virus was present in all major land cover classes in the region but was detected significantly more often in the forest than in other land cover types [51].…”

Section: Introductionmentioning

confidence: 99%

Potential for Zika Virus to Establish a Sylvatic Transmission Cycle in the Americas

et al. 2016

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Zika virus (ZIKV) originated and continues to circulate in a sylvatic transmission cycle between non-human primate hosts and arboreal mosquitoes in tropical Africa. Recently ZIKV invaded the Americas, where it poses a threat to human health, especially to pregnant women and their infants. Here we examine the risk that ZIKV will establish a sylvatic cycle in the Americas, focusing on Brazil. We review the natural history of sylvatic ZIKV and present a mathematical dynamic transmission model to assess the probability of establishment of a sylvatic ZIKV transmission cycle in non-human primates and/or other mammals and arboreal mosquito vectors in Brazil. Brazil is home to multiple species of primates and mosquitoes potentially capable of ZIKV transmission, though direct assessment of host competence (ability to mount viremia sufficient to infect a feeding mosquito) and vector competence (ability to become infected with ZIKV and disseminate and transmit upon subsequent feedings) of New World species is lacking. Modeling reveals a high probability of establishment of sylvatic ZIKV across a large range of biologically plausible parameters. Probability of establishment is dependent on host and vector population sizes, host birthrates, and ZIKV force of infection. Research on the host competence of New World monkeys or other small mammals to ZIKV, on vector competence of New World Aedes, Sabethes, and Haemagogus mosquitoes for ZIKV, and on the geographic range of potential New World hosts and vectors is urgently needed. A sylvatic cycle of ZIKV would make future elimination efforts in the Americas practically impossible, and paints a dire picture for the epidemiology of ZIKV and our ability to end the ongoing outbreak of congenital Zika syndrome.

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Section: Introductionmentioning

confidence: 99%

Potential for Zika Virus to Establish a Sylvatic Transmission Cycle in the Americas

et al. 2016

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“…First, while the main transmission pathway for ZIKV is through a mosquito vector [predominantly Aedes aegypti or Aedes albopictus (13,14)], a feature which has its own type of well-studied model and behavior (14)(15)(16), it can also spread through sexual contacts (17,18). Second, the probability of sexual transmission is highly asymmetric between males and females.…”

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confidence: 99%

Asymmetric percolation drives a double transition in sexual contact networks

Allard

Althouse

Scarpino

2017

Proc. Natl. Acad. Sci. U.S.A.

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Zika virus (ZIKV) exhibits unique transmission dynamics in that itis concurrently spread by a mosquito vector and through sexual contact. Due to the highly asymmetric durations of infectiousness between males and females-it is estimated that males are infectious for periods up to 10 times longer than females-we show that this sexual component of ZIKV transmission behaves akin to an asymmetric percolation process on the network of sexual contacts. We exactly solve the properties of this asymmetric percolation on random sexual contact networks and show that this process exhibits two epidemic transitions corresponding to a core-periphery structure. This structure is not present in the underlying contact networks, which are not distinguishable from random networks, and emerges because of the asymmetric percolation. We provide an exact analytical description of this double transition and discuss the implications of our results in the context of ZIKV epidemics. Most importantly, our study suggests a bias in our current ZIKV surveillance, because the community most at risk is also one of the least likely to get tested.A bstract modeling of epidemics on networks remains an active field, because some of the most basic features of epidemics are still misunderstood. The classic model is quite simple (1): disease spreads stochastically with a fixed transmission probability, T , through contacts around a given patient zero. The outbreak dies quickly if T is too small but spreads to a macroscopic fraction S of the entire population if T is larger than a threshold Tc. At Tc, most of the typical insights from phase transition theory are valuable. For instance, the sizes of microscopic outbreaks follow a power law distribution, such that the expected size of microscopic outbreaks, s , indicates the position of a phase transition. Indeed, as T increases, s monotonically increases, diverges exactly at Tc, and then monotonically goes down; meanwhile, the expected macroscopic epidemic size, S , starts increasing monotonically at Tc.However, simple modifications to this model can dramatically alter its phenomenology. The epidemic threshold can vanish in networks with a scale-free degree distribution (2) or in growing networks (3). The phase transition can be discontinuous in the case of complex contagions with threshold exposition or reinforcement (4), interacting epidemics (5, 6), or adaptive networks (7-9). Recently, a unique phenomenon of double-phase transitions has also been observed numerically when networks have a very heterogeneous and clustered structure (10, 11).The current Zika virus (ZIKV) epidemic exhibits two unique properties. First, while the main transmission pathway for ZIKV is through a mosquito vector [predominantly Aedes aegypti or Aedes albopictus (13, 14)], a feature which has its own type of well-studied model and behavior (14-16), it can also spread through sexual contacts (17, 18). Second, the probability of sexual transmission is highly asymmetric between males and females. Although this is also true for ot...

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“…The virus is explosive and unprecedented pace in the pandemic reemergence nature [27]. Therefore, knowing the associated driving factors is unquestionable.…”

Section: The Ecosystem and Other Factorsmentioning

confidence: 99%

Epidemiology, Driving Factors, Transmission and Control Options of Zika Virus: A Review

Gulich¹

2016

J Infect Dis Ther

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Now days, the threats of infectious diseases particularly that emerges and or re-emerges is increasing. The main sources of emerging and re-emerging diseases originated from both wild and domestic animals. From few years onwards, diseases such as HIV/AIDS, SARS, Rift Valley fever, Influenza, Ebola, and so like, become the risks of the world. This paper deals about the recently re-merged diseases known as Zika fever. This disease is caused by a virus known as flavivirus and carried from one individual to another through a mosquito called Aedes causes this disease. The viral epidemiology covers the Americans, Africa, Asia and the pacific. Though not all the reservoir hosts are clearly identified, authors in general agreed the primates are the main reservoirs. Researchers tried to identify the driving factors of Zika virus infection as climatic condition, presence of vectors, the environmental ecology, travelling histories, urbanization and so like. Individual persons infected by Zika virus will show symptoms such as mild fever, rashes on the skin, inflammation of conjunctiva, pain on the muscle and joint, headache. The symptoms may normally stay from the minimum day 2 to twelve days. Currently the disease has no treatment and viral prevention; only it relies on the protection of the mosquito bite. Special precaution steps should be taken in cases of pregnant women and who intend to recently pregnant.

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Impact of Climate and Mosquito Vector Abundance on Sylvatic Arbovirus Circulation Dynamics in Senegal

Cited by 82 publications

References 36 publications

Potential for Zika Virus to Establish a Sylvatic Transmission Cycle in the Americas

Potential for Zika Virus to Establish a Sylvatic Transmission Cycle in the Americas

Asymmetric percolation drives a double transition in sexual contact networks

Epidemiology, Driving Factors, Transmission and Control Options of Zika Virus: A Review

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