Preface

The Revised Authoritative Guide To Vaccine Legal Exemptions

Vaccines Have Serious Side Effects

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In the 1970s and 1980s, in an attempt to focus world attention on parasitic diseases, the World Health Organization formed the Tropical Diseases Research Group. Their target was six major infections that damaged the health of individuals in developing countries, and five of these six were parasitic diseases. The Rockefeller Foundation also identified parasitic infections as a major target for health improvement for the world community. They formed a research network to develop new drugs and vaccines by understanding the pathogenesis of diseases. Its title 'The Great Neglected Diseases Network' emphasised that, in the post-colonial world, parasitic diseases were no longer identified by governments and pharmaceutical companies as important subjects for medical research. Despite the success of these two ventures in developing our understanding of the immunology, molecular biology and potential for vaccines and drugs, the position of parasitic diseases in the world is, if anything, worse than it was 30 years ago. The territories in which malaria is endemic have expanded and the number of cases with it. Malaria causes more than a million child deaths in Africa every year. The number of individuals suffering from intestinal helminth infections has more than doubled in the last 50 years and the prevalence of schistosomiasis is rising. Urbanisation in Brazil, where more than 80% of the population live in cities, has resulted in large peri-urban epidemics of Chagas' disease and epidemics of visceral leishmaniasis. This general global deterioration has occurred in a context where, for many countries, endemic parasitic diseases are a thing of the past. In epidemiological terms, parasitic infections are over-dispersed or, in more everyday terms, focused in the poorest sector of the world community.

Globalisation has changed the spectrum of parasitic infection in clinical medical practice. Not only has the incidence of disease worldwide risen, but frequency of travel, migration and population dispersal due to war has resulted in individuals presenting with parasitic infections in locations where these diseases have become rare. Patients with malaria and intestinal protozoan and helminth infections are now an everyday occurrence in family practice throughout the world. The diagnosis of parasitic diseases has also become an everyday component of medical laboratory practice worldwide.

The HIV pandemic has also had a potent influence on the spectrum of parasitic infections. A number of organisms that cause disease rarely have become commonplace. The HIV epidemic itself was identified through an apparent epidemic of Pneumocystis carinii infection, at that time considered to be a protozoan and now considered to be a fungus. Intractable crypto-sporidiosis and isosporiasis, and the recognition of microsporidium infections and cerebral toxo-plasmosis, have all been consequences of severe immunocompromise secondary to HIV infection. Visceral leishmaniasis, too, has been recognised as a major opportunistic disease in HIV-infected individuals in Southern France and Italy.

New technologies have increased our ability to investigate parasitic diseases and to understand the biology of the organisms and the hosts' immune response to them. Developments in immunology and molecular biology have enabled diagnostic laboratories to improve the diagnosis of parasitic infections through enzyme-immu-noassays and DNA amplification techniques. Genome sequence programmes are under way for parasites, including malaria, Leishmania and amoebas and these may lead to the identification of new virulence determinants, or targets for chemotherapy or vaccine development. Although new treatments and vaccines have progressed more slowly than in other infection disciplines, effective chemotherapy is now available for almost all parasitic infections.

An international panel of authors have drawn together their experience and understanding of parasitic infections. The chapters contain a clinically orientated overview of all the major parasitic infections in medical practice. The editors hope that those who read and use this book will develop their clinical diagnostic and therapeutic skills, and that these skills will be used for the benefit of those who most need them—the people who are often the poorest in the world community.

Stephen H. Gillespie Richard D. Pearson

Figure 2.12 Discriminant analysis applied to the pre-1890 distribution of the tsetse Glossina morsitans in Zimbabwe. A single variable, the maximum of the mean monthly temperature, describes the overall distribution with an accuracy of 82%. The colours define the predicted probability of occurrence from low (red) to high (green) in the following bands: red = 0.00 - 0.349, pink = 0.35 - 0.449, red/yellow = 0.45 - 0.499, yellow/green = 0.50 - 0.549, pale green = 0.55 - 0.649 and green = 0.65-1.0. Reprinted from Rogers and Randolph, Distribution of tsetse and ticks in Africa, past, present and future. Parasitology Today 9: 266-71; © 1993, with permission from Elsevier Science

Figure 2.12 Discriminant analysis applied to the pre-1890 distribution of the tsetse Glossina morsitans in Zimbabwe. A single variable, the maximum of the mean monthly temperature, describes the overall distribution with an accuracy of 82%. The colours define the predicted probability of occurrence from low (red) to high (green) in the following bands: red = 0.00 - 0.349, pink = 0.35 - 0.449, red/yellow = 0.45 - 0.499, yellow/green = 0.50 - 0.549, pale green = 0.55 - 0.649 and green = 0.65-1.0. Reprinted from Rogers and Randolph, Distribution of tsetse and ticks in Africa, past, present and future. Parasitology Today 9: 266-71; © 1993, with permission from Elsevier Science

Figure 2.13 The distribution of Glossina morsitcms in Kenya and Tanzania (horizontal black lines) described using (A) a single variable, the maximum of the monthly normalized difference vegetation indices (NDVI 69% correct predictions), and (B) using nine additional climatological variables (84% correct predictions). Reprinted from Rogers and Randolph, Distribution of tsetse and ticks in Africa, past, present and future. Parasitology Today 9: 266-71; © 1993, with permission from Elsevier Science

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