Jean-Claude Manuguerra

Mankind must remain alert and united against existing and new infectious dieases

Numerous infectious diseases, viral, bacterial or parasitic, have accompanied mankind forever. They have thus influenced and sometimes even shaped the evolutionary dynamics of human populations in recent millennia. These infectious diseases have had an impact not only on the genetics of the individuals themselves, but also on entire populations by interfering with human activities. In the past, the impact of infectious diseases has been considerable: the Spanish flu pandemic of 1918-1919 caused forty million deaths (2% of the world population at the time) and also the terrible black plague epidemics which decimated almost 20% of the French population in the fourteenth century. Besides these exceptional disasters, we must remind ourselves of the devastation of “routine” persistent and recurring effect of infectious diseases in infant mortality and also in women during childbirth.

Since the late nineteenth century, the development of more hygiene conditions (particularly in the quality of drinking water), better nutrition, the advent and widespread use of vaccinations, the widespread use of insecticides and antibiotics are just some of the measures which led to a drastic decline in the share of infectious diseases in human morbidity and mortality. These changes facilitated an increase in life expectancy observed in most countries of the world during the twentieth century.
Thus, in the 1960s, the widespread view in the west was that infectious diseases would be better controlled. The success obtained by the WHO in the eradication of smallpox from the globe in 1977, only reinforced that idea.
In less than half a century, the situation has evolved. Many new infectious diseases have emerged, mostly viral (HIV / AIDS, Ebola...), others have re-emerged in areas where they had been eradicated, or at least controlled (Tuberculosis, Cholera ...), and finally some dramatically increased their geographical distribution (Dengue, West Nile virus encephalitis ...). There has also been an increase in the resistance of many bacteria and parasites known to pest control and antibiotic molecules.

Some of these emerging viruses and associated diseases have had a huge impact in terms of public health and socio-economic level. According to the 2004 report on the global AIDS epidemic published by the Joint United Nations Programme on HIV / AIDS (UNAIDS), the impact of AIDS on adult mortality between 1999 and the writing of the report had created a decline in life expectancy at birth in 23 African countries.
On another level, the cost of the outbreak of the severe acute respiratory syndrome (SARS) in Southeast Asia was estimated at nearly $50 billion. Indeed, this viral disease, which caused 800 deaths, completely paralyzed for several months both tourism and part of the trade in these areas. The West Nile virus, which causes encephalitis in humans, has become in less than two years, since 1999, a public health problem in the United States. Avian flu poses, since 2005, a real risk of a terrible human epidemic and strongly influences political decisions in the areas of human and animal health in many countries. The potential spread of the virus is responsible for the massive destruction by man, as a preventive measure, of tens of millions of poultry in both Southeast Asia and in some European countries. Nowadays the Zika virus, which had long been a virus for virological curiosity collection cabinets, has followed the path of the Chikungunya virus and is invading the American continent. This virus might cause neurological syndromes such as Guillain-Barré syndrome and even microcephaly in new born babies. We always have surprises with viruses: this mosquito transmitted virus can also be contagious through sexual activities.

These viruses and their associated emerging diseases very often created buzz in the media. Unknown or poorly known causes of the emergence in humans of these viruses, as well as the sometimes lethal nature of their associated diseases against which there is often no treatment, more or less regularly captivated the audience's attention. The sometimes rapid epidemic spread of these often exotic viruses (Central African forest for Ebola, SARS China ...) raised many questions and was a source of panic.
In 2000, the Global Outbreak Alert and Response Network (GOARN) was created to fight against epidemics under the coordination of the World Health Organization (WHO). This is a technical collaboration between existing institutions and networks that pool human and technical resources to rapidly identify and confirm outbreaks, and respond quickly.

Source : Que Sais-je - "Les virus Emergents" aux Presses Universitaires de France - 2006 - A. Gessain et J.-C. Manuguerra