Viruses and the Environment

191 Pages·1984·3.295 MB·English

by  J. I. Cooper, F. O. MacCallum (auth.)

Viruses and the
Environment
To
Audrey, Wendy and Elaine
Viruses
and the
Environment
J.1. Cooper
o.
F. MacCallum
Natural Environment Research Council,
Institute ofVirology
Oxford, UK
SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.
© 19841.1. Cooper and F.O. MacCallum
Originally published by Chapman and Hall in 1984
ISBN 978-94-015-7703-8 ISBN 978-94-015-7701-4 (eBook)
DOI 10.1007/978-94-015-7701-4
This title is available in both hardbound and paperback
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All rights reserved. No part ofthis book may be reprinted, or
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British Library Cataloguing in Publication Data
Cooper, I.!.
Viruses and the environment.-(Science paperback)
1. Viruses 2. Environmental health
I. Tide II. MacCallum F.O.
576' .64 QR360
ISBN 978-94-015-7703-8
oe
Library Congress Cataloging in Publication Data
Cooper, I. I.
Viruses and the environment.
(Science paperbacks; 192)
Bibliography: p.
Includes index.
1. Viruses. I. MacCallum, F. O. II. Tide.
III. Series. [DNLM: 1. Viruses. 2. Virus diseases -
Transmission. WC 500 C777v]
QR360.C65 1984 576' .64 84-14302
ISBN 978-94-015-7703-8
Contents
Acknowledgements ix
1 The nature of vimses 1
Introduction 1
Virus characteristics 2
Agents that were confused with viruses and how they differ 6
Virus names 7
Virus classification 8
Some approved virus taxa 10
Poxviridae 10
Herpesviridae 10
Iridoviridae 10
Parvoviridae 11
Papovaviridae 11
Geminiviruses 11
Reoviridae 11
Togaviridae 12
Orthomyxoviridae 13
Paramyxoviridae 13
Rhabdoviridae 14
Bunyaviridae 14
Retroviridae 1S
Picornaviridae IS
Caliciviridae 16
Cucumovirusus 16
Luteoviruses 16
VI V iruses and the environment
Closteroviruses 17
Tobamoviruses 17
Potyviruses 17
Potexviruses 18
Ungrouped viruses 18
Polymorphism, a consequence of multiple infection 18
Quasi-genetic interactions resulting from heterozygosity 20
Appendix - Virus families and groups recognized by
International Committee on Taxonomy ofViruses 24
2 Exposure to viruses and some consequences 27
Inoculation 27
Infection 28
Invasion 29
Responses to the challenge 32
Virus Transmission 34
Vertical transmission 34
Vertical transmission in vertebrates 34
Vertical transmission in seed plants 38
Vertical transmission in lower plants 41
Contact spread in plants 43
Virus transmission by fungi 45
Contact spread of viruses in vertebrates 46
Viruses in food 47
3 Viruses associated with invertebrates 50
Introduction 50
Invertebrates as virus vectors 50
Nematodes as virus vectors 52
Insects as virus vectors 56
Homoptera 56
Feeding habits 59
Virus retention and relationships with vectors 60
Heteroptera 65
Thysanoptera 66
Coleoptera 66
Diptera 67
Mechanical virus-vector association 67
Circulative-propagative association 68
Acarina as virus vectors 69
Contents Vll
As vectors for plant pathogenic viruses 69
As vectors of viruses pathogenic for vertebrates 70
Vertical transmission of viruses in insects and ticks 72
The range of insect-pathogenic viruses 73
Consequences of virus introduction into invertebrate
populations 78
Reactions to infection 80
Perennation of inocula 81
Viruses in soil 83
Occurrence of natural antibodies to invertebrate viruses
in wild and domesticated animals 86
Viruses infecting other invertebrates 87
4 Viruses and the terrestrial environment 89
The range of viruses in terrestrial vertebrates 89
The range of viruses in terrestrial plants 90
Factors affecting the occurrence of viruses 90
Geographical distribution 90
Rainfall 94
Temperature 95
Natural diversity and the biological components 97
The concept of host range 97
Factors facilitating acquisition of novel hosts 100
Yellow fever 100
Kyasanur forest disease 104
The broadcasting of viruses 109
In the air 109
On the wind 109
Viruses broadcast because of cornmerce or science 111
Epidemics, prospect and retrospect 114
5 Viruses in aquatic environments 117
Introduction 117
Indigenous sources of viruses 118
Some extraneous sources of virus contamination 119
The fate of virus-contaminated sewage 121
Agricultural use of waste water 123
Viruses in drinking water 124
The fate of sewage sludge 125
The contamination of seawater 126
Vlll V iruses and the environment
6 Strategies of virus maintenance in communities 128
Introduction 128
Agricultural plant populations 131
Naturally regenerating populations 133
Vertebrate populations 134
Application of predator-prey models to virus-host dynamics 135
Regulation of population growth by viruses 138
The influence of immunities on virus
maintenance in populations 141
Some problems in modelling multicellular virus-host systems 144
Unicellular populations in virus dynamics 145
The optimum maintenance strategy: speculation about
the cost and benefits of co-evolution 150
Conclusion 155
References 158
Author Index 171
Sub;ect Index 176
Acknowledgements
Grateful acknowledgement for suggestions and comments is due to
Drs R.M. Anderson, M.L. Edwards, K.A. Harrap, N. Moore and
T.W. Tinsley, and to Miss S. Mackenzie and P.R. Massaiski for
constructive criticism of certain sections of the text.
We are indebted to Mrs Joyce Bald, Miss Marlina Rowland and
particularly Miss Gail Davies for cheerfully typing the text.
We are grateful to the authors and publishers who gave permission
to reproduce illustrations and regret that not all such material has, in
the event, been included.
Chapter 1
The nature
ofviruses
INTRODUCTION
Viruses are ubiquitous yet when plants, animals and other biota are in
their natural environments, it is commonplace for virus replication to
occur in hosts that show no detectable abnormality. In many
instances, these inapparent (sometimes called latent or silent)
infections are potentially hazardous for Man, his domestic animals or
his crops. From time to time, drastic environmental changes occur
and whether these are attributable to natural phenomena or result
from human interference (agriculture, forestry, urbanization, war)
one consequence is liable to be a catastrophic increase in disease
incidence (epidemics). Analyses of epidemics have furthered
understanding of the complex interplay of factors that modify host
susceptibility/sensitivity on the one hand, while influencing the
abundance, virulence and invasiveness of the viruses on the other.
Often this experience has also given insight into the private lives of
virus populations that wax and wane in response to the constant
fluctuations in their micro-environments - out of sight and usually out
of mind. Commonly, the unmanaged components of the environment
are the sources of contagion - wild plants, including weeds in relation
to agriculturallhorticultural crops, migratory birds or commensal
rodents in human infections. Invertebrates, usually arthropods, are
the omnipresent go-betweens. However, virus transmission may be
independently achieved by contact or when the virus infects
reproductive organs, e.g. plant seed and pollen, fungal spores, animal
spermatazoa and ova. Alternatively, or additionally, the genetic
constituents (genomes) of viruses may become intimately associated
and replicate in harmony with the genomes of their hosts. There is a