Arboviruses: Molecular Biology, Evolution and Control.
Nikos Vasilakis and Duane J. Gubler, eds., 2016. 398 pp. Poole, UK: Caister Academic
Press. US$319, ISBN 978-1-910190-21-0
Arthropod-borne viruses (arboviruses) have a devastating impact on human health. The
arbovirus of greatest medical significance is dengue virus (family Flaviviridae),
which occurs in every, or almost every, country with a tropical or subtropical environment.
According to one recent estimate, dengue virus is responsible for 390 million infections
annually, of which 96 million are accompanied by clinical manifestations.1 Many other
arboviruses are also major human pathogens; for example, yellow fever, Japanese encephalitis,
West Nile, Zika, and tick-borne encephalitis viruses (Flaviviridae), chikungunya and
Venezuelan equine encephalitis viruses (Togaviridae), and Crimean-Congo hemorrhagic
fever, Oropouche, and severe febrile thrombocytopenia viruses (Bunyaviridae). Arboviruses
of major veterinary significance include Rift Valley fever virus (Bunyaviridae) and
bluetongue virus (Reoviridae). Most recognized arboviruses are maintained in natural
transmission cycles between wild vertebrate animals and hematophagous arthropods (i.e.,
mosquitoes, ticks, midges, and sandflies), and cause disease after spillover transmission
to humans or domestic animals that are dead-end hosts. However, some arboviruses—most
notably dengue, yellow fever, chikungunya, and Zika viruses—have lost the requirement
for enzootic amplification, and are maintained in human–mosquito transmission cycles.
The recent emergence of Zika virus and chikungunya virus in the Western Hemisphere
and the explosive disease outbreaks accompanied by these introductions provide a stark
reminder of how easily arboviruses can spread across the globe and cause devastating
disease in human populations. Despite the enormous burden that arboviruses impose
on human and animal health, very few books devoted specifically to arboviruses have
been published in recent years.
Arboviruses: Molecular Biology, Evolution and Control, edited by Nikos Vasilakis and
Duane J. Gubler, provides a thorough and compelling review on the current status of
arbovirology. The book is divided into four main sections and 22 chapters with contributions
from many of the world’s leading experts in the field. The first chapter, which is
preceded by an excellent foreword written by Scott C. Weaver and a preface written
by the two editors, provides a concise summary on arboviruses with a particular emphasis
on the taxonomic status of known, probable, and possible arboviruses (represented
by eight families, 25 genera, and 492 species). The current status of arboviral disease
and reasons for dramatic emergence of epidemic arboviral diseases (i.e., human population
growth and unprecedented urbanization) are also discussed.
Section I (chapters 2–8) covers the molecular biology of arboviruses. Topics included
in this section are taxonomy, genomic organization, replication, virus–vector and
virus–host interactions, and innate immune evasion. Chapter 2 contains two appended
tables; one that lists every traditional arbovirus currently recognized by the International
Committee on Taxonomy of Viruses, and another comprised of viruses that infect hematophagous
arthropods, but appear to have arthropod-specific host ranges. Many viruses listed
in the second table were discovered within the last few years and thus, are not covered
in many other virology books. The impact of next-generation sequencing technologies
and other recently developed molecular approaches on virus discovery and classification
is also covered. This section also compares the genomic organizations, translation
products, and replication strategies of the six virus families that contain most of
the arboviruses known to infect humans and livestock: alphaviruses (Togaviridae),
flaviviruses (Flaviviridae), rhabdoviruses (Rhabdoviridae), bunyaviruses (Bunyaviridae),
reoviruses (Reoviridae), and orthomyxoviruses (Orthomyxoviridae).
Section II (chapters 9–14) covers arboviral diversity and evolution. This section
provides an excellent review of ecological and epidemiological factors that influence
arbovirus genetic diversity, evolution, and emergence. The importance of host and
vector genetics and virus–host interactions is also discussed. One chapter is devoted
to the role of vertical transmission in the adaptation and evolution of arboviruses.
The major modes of vertical transmission are explained, and the contributors include
a table listing most of the bunyaviruses, flaviviruses, reoviruses, alphaviruses,
rhabdoviruses, and asfaviruses known or suspected to be vertically transmitted. There
is also a chapter on arbovirus genomics and metagenomics. Protocols for sample preparation,
whole genome sequencing, and data analysis are provided.
Section III (chapters 15–21) covers arbovirus diagnosis and control. The opening chapter
describes serologic and nucleic acid–based detection assays as well as virus isolation
methods available for arbovirus diagnosis. Nucleic acid–based diagnostics is the fastest
growing field in arboviral diagnosis, and assays covered in this chapter include the
widely used reverse transcription polymerase chain reaction as well as less common
methods such as fluorogenic assays, reverse transcription loop-mediated isothermal
amplification, and nucleic acid sequence–based amplification. The proceeding chapters
describe conventional methods available for arbovirus control (i.e., vector control,
biological control, and vaccination), and more recent approaches that hold promise
for future control efforts (i.e., the use of genetically modified vectors, RNA interference,
and small molecular drug development). The chapter on vaccination summarizes the current
status of dengue virus vaccine development, which has long been complicated by the
potential for disease enhancement to occur after exposure to a heterologous dengue
virus serotype and the unavailability of a suitable animal model. The 17D yellow fever
virus vaccine, which is potentially the safest vaccine ever developed, is also discussed
along with the current vaccine status of many other arboviruses of medical and veterinary
significance. Section IV consists of a single chapter “Arbovirology: Back to the Future”
written by Robert B. Tesh and Charles H. Calisher, two of the most recognized names
in the arbovirus community. These two individuals provide the reader with a historical
perspective of arbovirology and conclude with a discussion on future trends.
Overall, Arboviruses: Molecular Biology, Evolution and Control is an outstanding book.
An impressive team of contributors was involved in its conception, and each contributor
provides an excellent review of their particular research niche. This is arguably
the first comprehensive book devoted specifically to arboviruses to be published in
the last few decades. The book is highly recommended for every arbovirologist whether
it be a first-year graduate student or an established researcher.