Elsevier

Archives of Medical Research

Volume 33, Issue 4, July–August 2002, Pages 379-388
Archives of Medical Research

Review article
Flavivirus Susceptibility in Aedes aegypti

https://doi.org/10.1016/S0188-4409(02)00373-9Get rights and content

Abstract

Aedes aegypti is the primary vector of yellow fever (YF) and dengue fever (DF) flaviviruses worldwide. In this review we focus on past and present research on genetic components and environmental factors in Aedes aegypti that appear to control flavivirus transmission. We review genetic relationships among Ae. aegypti populations throughout the world and discuss how variation in vector competence is correlated with overall genetic differences among populations. We describe current research into how genetic and environmental factors jointly affect distribution of vector competence in natural populations. Based on this information, we propose a population genetic model for vector competence and discuss our recent progress in testing this model. We end with a discussion of approaches being taken to identify the genes that may control flavivirus susceptibility in Ae. aegypti.

Section snippets

Population Genetics of Aedes aegypti

Aedes aegypti has a cosmopolitan distribution between the 40°N and 40°S latitudes and is phenotypically polymorphic, varies in gene frequencies as detected by biochemical and molecular genetic markers, and exhibits variation in vector competence for arboviruses. In sub-Saharan Africa, Ae. aegypti appears as a black sylvan race or subspecies, Ae. aegypti formosus, that oviposits primarily in treeholes. A light-colored domestic race, Ae. aegypti aegypti is distributed in tropical and subtropical

Physiologic Genetics of Vector Competence

Figure 2 is a generalized diagram showing potential barriers to transmission that an arbovirus must overcome to be transmitted by a mosquito vector (22). Following ingestion in a bloodmeal, the arbovirus must first infect midgut epithelial cells of the vector. Presumably, virions interact with receptors on midgut epithelial cells and penetrate the cells. Uncoating, transcription, and translation of the virus genome is followed by virion maturation. Then, infectious virions must disseminate from

Environmental Factors Also Control Arbovirus Transmission

Biological transmission of arboviruses by a mosquito involves complex interactions among intrinsic biological factors in the mosquito and virus and extrinsic, environmental factors. Vector competence in an individual mosquito is a function of biological barriers discussed previously that an ingested virus must pass through to be replicated and finally transmitted. However, functioning of these barriers on a strictly deterministic basis would fail to explain the large variation in vector

Variation for Flavivirus Vector Competence in Aedes aegypti

Several studies have documented wide variation among and within populations of Ae. aegypti in vector competence for flaviviruses. Geographic variation in oral infection rates with YF was demonstrated among 28 populations of Ae. aegypti worldwide (33). Patterns of oral susceptibility correlated with the eight genetic groupings identified by allozyme analysis previously described (17). Least susceptible mosquitoes were from the sylvan formosus populations (7–34% with disseminated infection [DI]),

Quantitative Genetics of Vector Competence in Aedes aegypti

Quantitative genetics provides a useful tool for determining the degree to which a phenotypic trait is controlled by genetic and environmental factors. It also provides a means to determine the ways that alleles contribute to the phenotype. We have discussed that susceptibility to arboviruses appears to be under the control of multiple loci and subject to environmental effects. We performed a quantitative genetic study of the ability of Ae. aegypti to propagate DEN-2 in the midgut and in a

Mapping Genes That Control Flavivirus Vector Competence in Aedes aegypti

All research to date indicates that level of DEN infection in Ae. aegypti is a quantitative rather than a discrete variable appearing to be distributed continuously among individuals and subject to environmental effects. Recent molecular genetic and statistical advances permit mapping of loci affecting expression of quantitative traits, termed quantitative trait loci (QTL). Severson and colleagues 62, 63 mapped in Ae. aegypti the QTL that condition susceptibility to filarial worms (64) and

Genetics of Vector Competence in Aedes aegypti Populations

Information presented in this review suggests a general model for the dynamics of flavivirus vector competence in Ae. aegypti populations. Our results suggest that variation in dengue infection rates among natural populations of Ae. aegypti may be due to segregation of alleles at each of the three QTL. Differences in dengue susceptibility between Ae. aegypti aegypti and Ae. aegypti formosus populations may reflect differences in frequency of alleles at MIB and MEB loci but may also arise from

Identification of Genes Controlling Vector Competence in Aedes aegypti

Our results suggest that alleles at primarily three independently segregating loci create an MIB or MEB for flaviviruses in Ae. aegypti. Alleles at these loci act additively both within each QTL and independently among QTL. Other loci of minor effect may also be involved. The additive genetic pattern observed could reflect differences among genotypes in 1) density of a virus receptor on midgut cells, 2) abundance of intracellular factors needed for viral replication, or 3) abundance of

Acknowledgements

This research was supported by NIH grants U01AI45430 and R01-AI49256. NG-E was supported by NIH Fogarty Center Training grant D43 TW01130.

References (69)

  • F.G. Noriega et al.

    Neuroendocrine factors affecting the steady-state levels of early trypsin mRNA in Aedes aegypti

    J Insect Physiol

    (2001)
  • L. Lepiniec et al.

    Geographic distribution and evolution of yellow fever viruses based on direct sequencing of genomic cDNA fragments

    J Gen Virol

    (1994)
  • T.P. Monath

    Denguethe risk to developed and developing countries

    Proc Natl Acad Sci USA

    (1994)
  • T.P. Monath

    Vector-borne emergent disease

    Ann NY Acad Sci

    (1994)
  • B.R. Miller et al.

    Epidemic yellow fever caused by an incompetent mosquito vector

    Trop Med Parasitol

    (1989)
  • G. Kouri et al.

    Reemergence of dengue in Cubaa 1997 epidemic in Santiago de Cuba

    Emerg Infect Dis

    (1998)
  • J.N. Hanna et al.

    Two contiguous outbreaks of dengue type 2 in north Queensland

    Med J Aust

    (1998)
  • S.K. Lam

    Emerging infectious diseases—Southeast Asia

    Emerg Infect Dis

    (1998)
  • A. Dove

    Dengue fever on the increase

    Nat Med

    (1998)
  • N.G. Gratz

    Emerging and resurging vector-borne diseases

    Annu Rev Entomol

    (1999)
  • O. Chareonsook et al.

    Changing epidemiology of dengue hemorrhagic fever in Thailand

    Epidemiol Infect

    (1999)
  • G. Avilés et al.

    Dengue reemergence in Argentina

    Emerg Infect Dis

    (1999)
  • K.I. Yamada et al.

    The features of imported dengue fever cases from 1996 to 1999

    Jpn J Infect Dis

    (1999)
  • W.J. Tabachnick

    The yellow fever mosquitoevolutionary genetics and arthropod-borne disease

    Am Entomol

    (1991)
  • W.J. Tabachnick et al.

    A world-wide survey of genetic variation in the yellow fever mosquito, Aedes aegypti

    Genet Res

    (1979)
  • B.L. Apostol et al.

    Population genetics with RAPD-PCR markersthe breeding structure of Aedes aegypti in Puerto Rico

    Heredity

    (1996)
  • N. Gorrochótegui-Escalante et al.

    Genetic isolation by distance among Aedes aegypti populations along the northeastern coast of Mexico

    Am J Trop Med Hyg

    (2000)
  • N. Gorrochótegui-Escalante et al.

    The breeding structure of Aedes aegypti populations in Mexico varies by region

    Am J Trop Med Hyg

    (2002)
  • G.P. Wallis et al.

    Macrogeographic genetic variation in a human commensalAedes aegypti, the yellow fever mosquito

    Genet Res

    (1983)
  • J.L. Woodring et al.

    Natural cycles of vector borne pathogens

  • G. Xu et al.

    VP7an attachment protein of bluetongue virus for cellular receptors in Culicoides variipennis

    J Gen Virol

    (1997)
  • G.V. Ludwig et al.

    A putative receptor for Venezuelan equine encephalitis virus from mosquito cells

    J Virol

    (1996)
  • K.E. Olson et al.

    Development of a Sindbis virus expression system that efficiently expresses green fluorescent protein in midguts of Aedes aegypti following per os infection

    Insect Mol Biol

    (2000)
  • C.F. Bosio et al.

    Quantitative trait loci that control vector competence for dengue-2 virus in the mosquito Aedes aegypti

    Genetics

    (2000)
  • Cited by (283)

    • Clinical Antiviral Natural Products and Approved Drugs

      2024, Promising Antiviral Herbal and Medicinal Plants
    View all citing articles on Scopus
    View full text