Diseases and Human Evolution

22: The New Viral Wars and Sleeping Dragons

CHAPTER 22 The New Viral Wars and Sleeping Dragons The rapidly growing populations of today’s world face many challenging environmental, economic, and geopolitical problems. There are simply too many people pressing for finite land and water resources for survival and economic gain. Human populations are spilling over and settling into onetime wilderness areas. Major rain forests are being destroyed. Giant dams are being built to control water sources, thereby upsetting local ecological zones. Huge numbers of refugees fleeing famine and social, economic, and political turmoil find themselves displaced and barely surviving in a marginal existence , often living in makeshift camps or megacity slums. Turmoil around the globe has presented us with new challenges from the microbe world. We keep stirring the pot, mixing germs from all over the planet as we break down geographic barriers that once kept them localized and separated. The constant global movements of people and commerce have been acting as conduits for infectious microbes to travel from one place to another. Today, maverick viruses pose a new threat to human populations. They can arise basically in one of three ways: evolutionary production of a new variant of a recognized virus; a virus jumping from an animal species to human beings; or relatively unknown viruses existing in small isolated populations entering larger populations with first-time recognition. Maverick viruses usually emerge with environmental disturbances or changes in human behavior patterns (Morse 1993). Current environmental and social upsets around the world have provoked the appearance of many such viruses. 387 The HIV/AIDS Pandemic The human immunodeficiency virus (HIV) infecting humans originated as a natural infection of chimpanzees. The virus evolved into a silent infection causing no harm within its natural host. Chimpanzees that were hunted and slaughtered for food by rural peoples gave the virus the opportunity to jump species and infect humans during the butchering process. It would only take a skin scratch or nick in contact with infected blood or other body fluids of the animal to permit infection. Most likely the virus sporadically infected rural people in isolated areas of the Congo with deadly results for many years before its escape from rural central Africa during the latter half of the twentieth century (Kanki and Essex 2000). The virus quickly adapted to human beings to become a human disease transmitted through blood and sexual contact. Many Africans’ lives were disrupted as colonial Africa began to nationalize during the second half of the twentieth century. A chain of destabilizing events took place across the continent, facilitating the spread of both old and new infectious diseases, including HIV. Between 1970 and 1975 subSaharan Africa saw itself torn apart by ruthless rulers, civil wars, and tribal conflicts augmented by severe drought and famine. Hardest hit was the Congo area of central Africa, especially Uganda under Idi Amin’s rule. By the end of the 1970s, HIV and the disease it caused, acquired immune deficiency syndrome (AIDS), had radiated outward from the eastern shores of Lake Victoria to become endemic throughout the region (Garrett 1994). The virus, once confined to isolated rural villages, escaped into the general population of the region as rural people were driven from their homes to more populated areas. Military troops moving through the area also picked up the virus and carried it back to their home regions. Regional truck drivers and prostitutes further contributed to the spread of the virus into urban areas. Spread of the virus was facilitated by the constant reuse of contaminated needles both within medical facilities and on the street. Routine vaccinations for many children, and the uncontrolled use of injectable medications adapted by street entrepreneurs, turned deadly when contaminated needles were reused. Children and adults treated for malaria with contaminated blood transfusions in clinical facilities also became easy prey for the virus (Garrett 1994). The virus probably would not have been able to spread so quickly throughout Africa if needle use and blood transfusions had taken place under stringent controls. 388 CHAPTER 22 The world did not know what was happening in central Africa. People outside Africa mostly ignored reports of the mysterious “slim” disease and the surge of rare cancers and diseases related to AIDS killing tens of thousands of people in this part of the world. Many Africans blamed witchcraft for the carnage, and African governments denied the seriousness of the epidemic (Garrett 1994). While the continent of Africa...