Webber - Communicable diseases: a global perspective

Communicable Diseases, 5th Edition

A Global Perspective

20th Anniversary Edition

This book is dedicated to Michael Colbourne (19191993), malariologist, teacher and previous Dean in the Universities of Hong Kong and Singapore, who while at the London School of Hygiene and Tropical Medicine gave me considerable help in its preparation.

And also to

Brian Southgate (19302011), teacher, mentor and an authority in many fields, who was a constant support and helper in the development of this book.

Communicable Diseases, 5th Edition

A Global Perspective

20th Anniversary Edition

Roger Webber

Watermell, Ardfern, Lochgilphead, Argyll PA31 8QN, UK (r-webber@live.co.uk) Formerly of London School of Hygiene and Tropical Medicine

CABI is a trading name of CAB International

Roger Webber 2016. All rights reserved. No part of this publication may be reproduced in any form or by any means, electronically, mechanically, by photocopying, recording or otherwise, without the prior permission of the copyright owners.

A catalogue record for this book is available from the British Library, London, UK.

Library of Congress Cataloging-in-Publication Data

Names: Webber, Roger, author. | C.A.B. International, issuing body.

Title: Communicable diseases : a global perspective / Roger Webber.

Description: 5th edition. | Wallingford, Oxfordshire ; Boston, MA : CABI, [2016] | 20th anniversary edition. | Includes bibliographical references and index.

Identifiers: LCCN 2016000627 (print) | LCCN 2016002112 (ebook) | ISBN 9781780647425 (pbk : alk. paper) | ISBN 9781780647432 (pdf) | ISBN 9781780647449 (ePub)

Subjects: | MESH: Communicable Disease Control | Communicable Diseases--epidemiology

Classification: LCC RA643 (print) | LCC RA643 (ebook) | NLM WA 110 | DDC 616.9--dc23

LC record available at http://lccn.loc.gov/2016000627

First edition 1996 ISBN 978 0 85199 138 2

Second edition 2005 ISBN 978 0 85199 902 9

Third edition 2009 ISBN 978 1 84593 504 7 (pbk) 978 1 84593 505 5 (hbk)

Fourth edition 2012 ISBN 978 1 84593 938 0 (pbk) 978 1 84593 939 7 (hbk)

ISBN: 978 1 78064 742 5 (pbk)

978 1 78064 741 8 (hbk)

Commissioning editor: Caroline Makepeace

Editorial assistant: Alexandra Lainsbury

Production editor: Tracy Head

Typeset by SPi, Pondicherry, India

Printed and bound by Gutenberg Press Limited, Tarxien, Malta

Contents

Since the last edition, the pandemic of A(H1N1) influenza, so-called swine flu, fortunately did not develop into a serious problem and declined without any major consequences. Similarly, variant Creutzfeldt-Jakob disease (vCJD) did not become transmitted by blood products as was feared and has now come to an end. On the negative side has been the increase in food-borne infections due to the international trade in poultry and meat produce, and the alarming appearance of multidrug-resistant organisms in many infections. This has caused considerable problems in the treatment of tuberculosis, while some hospital infections are now resistant to every known antibiotic. There has also been the appearance of artemesinin-resistant malaria and an increasing problem in treating cases of human immunodeficiency virus (HIV) infection. An epidemic of zika has been ongoing since 2012, but the manifestation of congenital changes is a new feature of an arboviral disease.

An unexpected problem was the outbreak of Ebola centred on the three West African countries of Guinea, Sierra Leone and Liberia. Outbreaks of Ebola have occurred in the past but, because of the high mortality in often isolated communities, they have remained contained. Unfortunately on this occasion there was a higher density of population and extensive spread took place before containment measures were started, so it then became difficult to restrict the outbreak, resulting in a large number of deaths.

A new disease, Middle East respiratory syndrome (MERS), was identified in 2012 in the Arabian peninsula and has spread to 26 countries, producing 1112 laboratory-confirmed cases and 422 deaths by 11 May 2015. Infection initially appears to have come from camels but is then transferred by close human contact.

Communicable diseases are still the major killers in the world, with tuberculosis, malaria and HIV taking a huge annual toll (approximately 45 million deaths). In the developing world, just to survive childhood is the major challenge to life as acute respiratory infections (ARIs) and diarrhoeal diseases account for some 6 million young lives every year. Gratifyingly, the use of insecticide-treated mosquito nets (ITN) and the addition of chemoprophylaxis to the immunization schedule in Africa has seen a 40% decline in childhood deaths from malaria.

Progress on the control of poliomyelitis has continued, with the South-East Asian Region of the World Health Organization (WHO) certified free of the virus on 27 March 2014, to join the regions of Europe, the Americas and the Western Pacific. Eighty per cent of the worlds population now live in polio-free areas. Guinea worm has been cleared from most of the endemic area by simple improvements in water supply, a tribute to rudimentary health measures. Leprosy, the disease of antiquity, has, owing to an active search and find programme, decreased by such a degree that it is no longer a health problem in many countries. Eighty per cent of all new cases are found in three countries: Brazil, India and Indonesia.

On 29 April 2015, the WHO Region of the Americas was certified as having eradicated measles. This has been an incredible achievement and gives hope that similar action can eliminate this disease from other parts of the world.

The development of new vaccines has been a tribute to the research and development sector, with the general availability of vaccines against meningitis, pneumococcal infection, rotavirus and human papilloma virus now added to the routine vaccination programmes in many countries. From June 2016, yellow fever vaccination will be considered to give life-long protection.

The appearance of new diseases and the persistence of infections that have always been with us means that a knowledge of communicable diseases is still necessary. This is even more so in the developing world where the burden of communicable diseases is the major health problem. While individuals fall sick and require the expertise of the medical profession, it is the overall assessment of the cause of diseases and how to control them that will most rapidly solve the problem in the community. Indeed, communicable diseases are community problems and need to be looked at in this way.

Learning about these diseases one by one is a long and complicated process, yet it is the method of transmission that is the key to control, with several diseases sharing the same method of transmission. This allows diseases to be grouped together so that knowing the characteristics of one means that any of the diseases in the group can probably be controlled in a similar way. While there are always exceptions, grouping communicable diseases makes this easier and is one of the intentions of the book. This approach seems to have been borne out as the previous editions have been used as course books for several teaching programmes and it is hoped that changes made in this edition will make it even more suitable. The first edition of what was then called