Essential Malariology, 4Ed

David A. Warrell, Herbert M Gilles

• Publisher: CRC Press
• Year: 2017
• Print ISBN: 9780340740644
• eBook ISBN: 9781351449748
• Topic: Medicine
• Subtopic: Medical Theory, Practice & Reference

Essential Malariology, Fourth Edition is a concise and practical handbook that covers all aspects of malaria from a clinical perspective - its control, prevention and treatment. This edition has been thoroughly updated and contains brand new chapters on malaria in children, malaria in pregnancy, and vaccines. Incorporated throughout are the latest research into, and understanding of, molecular biology, and the latest diagnostic techniques. In addition, new colour plates and figures are included to complement the text.

1

Historical outline

HERBERT M GILLES

Milestones in the history of malaria and its control

Selected references

The great antiquity of malarial infection is confirmed by the fact that well over 100 parasite species similar to those of humans are found in a wide range of vertebrates from reptiles or birds to higher apes. None of these parasites, except for those found in some monkeys, can be transmitted to humans. This high host specificity indicates a long association between the human species and the four particular species of plasmodia that infect humans.

References to seasonal and intermittent fevers exist in the ancient Assyrian, Chinese and Indian religious and medical texts, but their true identity with malaria is uncertain. These afflictions, usually ascribed to the punishment of gods or vengeance by evil spirits, were met by incantations or sacrificial offerings. Hippocrates, who lived in Greece in the fifth century BC, was the earliest physician to discard superstition for logical observation of the relationship between the appearance of the disease and the seasons of the year or the places where his patients lived. He was also the first to describe in detail the clinical picture of malaria and some complications of the disease.

Celsus (25 BC-54 AD) gave a particularly accurate description of the various types of malaria:

Now quartan fevers have the simpler characteristics. Nearly always they begin with shivering, then heat breaks out and the fever having ended, there are two days free; thus on the fourth day it recurs.

But of tertian fevers, there are two classes. The one, beginning and desisting in the same way as quartan, has merely this distinction, that it affords one day free, and recurs on the third day. The other is far more pernicious; and it does indeed recur on the third day, yet out of forty-eight hours, about thirty-six, sometimes less, sometimes more, are in fact occupied by the paroxysm, nor does the fever entirely cease in the remission, but only becomes less violent.

At the beginning of the seventeenth century came the discovery of the value of ‘Peruvian’ bark for the treatment of fevers. Morton and Sydenham in England and later Torti in Italy differentiated between the true intermittent fevers and others that failed to respond to the drug, which was then known as ‘Jesuit’s powder’.

In the eighteenth century, these specific fevers, known in England as ‘agues’, received the Italian name ‘malaria’, because it was then widely believed that their cause was related to the foul air common near marshy areas. The French term ‘paludisme’, indicating a close connection with swamps, was introduced much later. In 1735, the tree producing the Peruvian bark was given its scientific name of Cinchona by Linnaeus. But quinine, the active principal of it, was not isolated until 1820, by Pelletier and Caventou in France.

It was in 1880 that Laveran, a French army surgeon in Algeria, first saw and described malaria parasites in the red blood cells of human beings. Soon after that, Romanowsky in Russia developed a new method of staining the malaria parasites in blood films and this, together with the improvement of the microscope, made further studies of plasmodia very much easier.

However, the way in which the disease was transmitted from person to person was still a mystery. The elucidation of the actual mode of transmission was not forthcoming until 1897, when Ronald Ross, working in Secunderabad (India), found a developing form of the malaria parasite in the body of a mosquito that had previously fed on a patient with the plasmodia in his blood. The whole complex picture of the cycle of development of malaria parasites in humans and in the female Anopheles mosquito became clear as a result of further studies by the Italians Amico Bignami, Giuseppe Bastianelli and, especially, Battista Grassi in 1898–9.

During the twentieth century, much research was devoted to malaria control. Larvicides in the form of oil of Paris green were introduced to prevent the breeding of mosquitoes in various types of waters. Wider use of these and other methods of mosquito reduction demonstrated the practicability of controlling malaria and yellow fever in Cuba and the Panama Canal Zone, where two American campaigns organized by General William Crawford Gorgas proved to be outstanding successes. Subsequently, Malcolm Watson in Malaya introduced the concept of ‘naturalistic control’ based on the knowledge of the breeding habits of species of Anopheles involved in the local transmission of the disease.

The ravages of malaria experienced during the First World War and the difficulties of securing cheap supplies of quinine stimulated a line of research in Germany aimed at the discovery of synthetic anti-malarial drugs. This was brilliantly accomplished in 1924 by Schulemann’s discovery of pamaquine. However, a much more valuable drug – Atabrin (mepacrine) – was prepared in 1930 by Kikuth, Mietzsch and Mauss. There can be no doubt that the availability of this compound played a very important role during the Second World War. Other valuable synthetic drugs developed by the Germans, the French, the Americans and the British followed in 1934 (chloroquine), 1944 (proguanil), 1946 (amodiaquine), 1950 (primaquine) and 1952 (pyrimethamine).

In the meantime, another major discovery was to revolutionize the technique of malaria control by spraying insecticides against adult mosquitoes.

At the beginning of the Second World War, Paul Muller discovered in Switzerland the strong insecticidal action of a synthetic compound, dichlorodiphenyl-trichloroethane, which was given the abbreviated name of DDT.

Among other residual insecticides that were introduced soon after DDT, hexachlorocyclohexane (BHC or HCH) and dieldrin should be mentioned.

In 1901, Grassi had formulated the idea that there is a third, cryptic tissue phase following the inoculation of sporozoites by the bite of Anopheles. Raffaele in Italy was the first to demonstrate in 1934 the existence of this phase in bird malaria. Then, in 1948, the exo-erythrocytic stages, first of monkey malaria (Plasmodium cynomolgi) and then of human malaria (P. vivax), were discovered in the UK by Shortt and Garnham. This discovery explained what happens to the parasite during the incubation period and how the relapses of malaria infection occur.

The possibility of global extension of malaria control activities to bring about the final eradication of the disease was contemplated in the 1950s when the results of the application of DDT in Venezuela, Italy, Greece, Guyana, Ceylon and the USA showed great promise.

The concept of malaria eradication was adopted by the World Health Assembly in 1995, and 2 years later the World Health Organization (WHO) launched a global campaign. Its results over the next 15 years were excellent in Europe, North America, some parts of Asia, the former USSR and Australia, and less good in tropical countries. The causes of this lack of progress are many and are fully dealt with in the appropriate section of this book. In 1969, WHO revised the strategy of malaria eradication by stressing the need for greater involvement of general health services and for extension of research on new insecticides, improved surveillance, development of new antimalarial drugs and alternative methods of malaria control.

However, during the past decade there has been a considerable increase of malaria in several tropical areas, where in the past the eradication programmes appeared to advance satisfactorily. This resurgence of the disease was greatest in southern and southeastern Asia, but there was also an increased incidence in Central America and parts of South America; a serious epidemic of malaria occurred in the Asian part of Turkey. In tropical Africa, the malaria situation has also deteriorated. Severe outbreaks have occurred in several countries, with a high mortality and a shift of morbidity to older age groups. Uncontrolled and rapid urbanization has created pockets of transmission in the cities, thus increasing the size of vulnerable groups. Chloroquine resistance of P. falciparum has spread throughout the African continent. In Southeast Asia, multidrug resistance is now commonly encountered. Political concern and the will to reduce morbidity and mortality from malaria were mobilized at a Ministerial Conference held in Amsterdam in 1992.

Remarkable progress has been made in scientific activity related to malaria during the past 25 years, since the United Nations Development Programme (UNDP)/World Bank/WHO Tropical Diseases Research and Training Programme extended malaria research over the whole range of the host-parasite relationship, including the mosquito vector, the socio-economic impact of the disease, and the sequencing of the falciparum genome. Progress in drug development – apart from the discovery of mefloquine and artemisinin and its analogues – has been slow and a vaccine remains an elusive, though attainable, target.

In 1997, heads of states of Africa met in Harare, Zimbabwe, and issued a Declaration on Malaria Prevention and Control in the Context of African Economic Recovery and Development. This important African political commitment was endorsed by the leaders of the industrialized G8 nations, with a promise of substantial financial support.

In 1998, WHO announced that malaria was to be one of its top priorities and introduced a new initiative, ‘Roll Back Malaria’, aimed at developing a sectorwide approach to combat the disease.

Two other major malaria initiatives – the Multilateral Initiatives on Malaria (MIM) aimed at strengthening research capacity in Africa and the African Initiative on Malaria (AIM) – were established.

MILESTONES IN THE HISTORY OF MALARIA AND ITS CONTROL

The main chronological landmarks in the advance of our knowledge of malaria and the control or eradication of this disease followed three different and yet related roads. This list of major events related to the history of malaria is necessarily arbitrary and incomplete.

Malaria parasites and their transmission

1847 Dempster in India introduced spleen palpation of children as an index of epidemicity of malaria.

1848 Virchow and Fredrichs in Germany recognized that the presence of pigment in internal organs may be related to deaths from intermittent fevers.

1878 Manson in China showed that a mosquito (Culex fatigans) can act as a vector of human filaria.

1880 Laveran in Algeria discovered and described malaria parasites in human blood.

1886 Golgi in Italy described in detail two species of human malaria parasites (P. vivax and P. malariae).

1889 Danilewski in Russia described the morphology of avian parasites and indicated their wide distribution.

1889–90 Celli and Marchiafava in Italy described P. falciparum.

1891 Romanowsky developed his polychrome staining method for demonstrating plasmodia in blood smears.

1894 Manson put forward the theory that malaria is transmitted from person to person by mosquitoes.

1897 Ross discovered pigmented cysts (oocysts) on the stomach wall of an Anopheles mosquito (probably A. stephensi) in Secunderabad, India.

1897 MacCallum in the USA described the sexual phase of Haemoproteus in the blood of a crow, and observed exflagellation of a male gametocyte in P. falciparum and the penetration of a female gametocyte by a flagellum.

1898 Ross worked out the complete cycle of bird malaria in naturally infected sparrows in Calcutta.

1898 Grassi, Bignami and Bastianelli in Italy described the cycle of human malaria parasites in Anopheles mosquitoes.

1900 Manson, by experiments with human volunteers in the Roman Camp...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Contributors
• 1 Historical outline
• 2 The malaria parasites
• 3 Diagnostic methods in malaria
• 4 The Anopheles vector
• 5 The epidemiology of malaria
• 6 Rationale and technique of malaria control
• 7 Clinical features of malaria
• 8 Clinical features of malaria in children
• 9 Clinical features of malaria in pregnancy
• 10 Pathology and pathophysiology of human malaria
• 11 Immunology of malaria
• 12 Treatment and prevention of malaria
• 13 Malaria vaccines
• Appendix: Characteristics of some major Anopheles vectors of human malaria
• Index