The trans-species jump from the animal reserve (first part)

Natural Pigelleto reserves

MICROBIOLOGIC CONSEQUENCES OF HUMAN CIVILIZATION

With the progress of civilization man invades new geographical areas which, till that moment, had been incontested dominion of other animal populations favouring this way the trans-species jump from the animal reserve to man.

Bacteria and viruses which had been present in the latter since the remote past were one of the factors of the numerical regulation of the animal populations living there. The number and heterogeneity of these microorganisms are really huge.

This animal reserve is an inexhaustible tank of bacteria and viruses. Every time man alters, somehow, the balance of this reserve or anyway comes, compulsorily, into touch with it,always new species of microorganisms may make the so called “trans-species jump”[1], that is passing from the animal reserve to man. In the original species viruses and bacteria achieved a balance with their hosts by following the same law regulating either the number of predators or respective preys. When they pass to human population, this balance doesn’t exist and besides it’s man the one who often offers microorganisms an opportunity to spread. Bacteria and viruses, like any other living creatures, aim at surviving.

In small nomade groups, as long ago men were organized, an infectious agent, a highly transmissible and virulent one, would have spead rapidly and with the death of all its hosts it would have killed itself. Since this is not the microorganism’s purpose epidemics with very infectious and lethal agents were rare in small communities. When the number of human beings in a certain area greatly increases, a virus that spreads rapidly and as quickly kills all its hosts can, anyway, survive because before a host dies it passes to another one or survives as long as it’s sufficient to find another host. As an epidemic reduces the population, the virus becomes less transmissible and virulent and man stronger, this way a balance between predator(virus) and man is formed. Just this balance existed in the animal reserve from where the virus had passed to man, that is it had made the trans-species jump from the animal reserve to man. Throughout history conditions man offered microorganisms to spread are really a lot: environmental overcrowding, above all without an adequate hygiene, destruction of large green areas where viruses and bacteria live keeping a balance with other species living in the animal reserve, sexual promiscuity, rapid transfer of large masses from a territory to another moving this way pathogens from zones where they had got a balance also with the human population to other ones where they were unknown.

Primate manipulation itself to make vaccines may cause new epidemics both because it produces an artificial overpopulation of primates themselves and because it can, by chance, bring man into contact with the internal tissues of these animals.

Primate manipulation

A kind of mosquito, the Anopheles Gambiae, which was used to feeding on human blood, proliferated in the deforested zones of the Mediterranean sea; since men were prevailing over other animal species in deforested areas, obviously the Anopheles Gambiae supplanted the other species of mosquitos which were used to feeding on the blood of creatures different from man.

Anopheles Gambiae

As a consequence the malarial cycle intensified enormously. Every human being who ventured on those deforested lands was affected by malaria. The only one resource of African and generally Mediterranean farmers was a genetic mutation according to which normal red corpuscles were replaced by microcytes less hospitable than the others with regards to plasmodium of malaria[2].

During the Middle Ages leprosy was a very diffuse disease

leprosy in the Middle Ages

In the XIII century there were about 19,000 leper hospitals all over the Christian world. According to some scholars leprosy included all a series of skin diseases besides the specific one. One of these infections is Framboesia which causes some wide and deep ulcers on the skin. Framboesia is caused by a Spirochaeta that can’t be distinguished from the one causing Syphilis.

Leper with a bell XIV SEC

If we admit the Spirochaeta of Framboesia is the same of the one of Syphilis we can understand why at a certain point Framboesia, together with all the other skin diseases included in the word Leprosy, became rare while Syphilis spread enormously all over the world.

In the case of Framboesia, in fact, the Spirochaeta needs a prolonged skin to skin contact to pass from an individual to another, since skin exercises a certain protection as to bacterial and viral attacks.

During the Middle Ages the poverty of many peasants was such that they would sleep close to each other during the very cold winter nights, without any protection but their skin. This way that prolonged skin to skin contact necessary to the diffusion of Framboesia was carried out.

Because of the heavy demographic decline of the XIV century there were much fewer people to share the means of subsistence of a certain area. We know in that period a considerable export of wool textiles from Europe eastward also caused by an increase of sheep population starts.

The fall of the empire

Therefore from a certain moment on it’s probable also for European peasants to be able to purchase more wool fabric to cover themselves during winter time.

So Spirochaeta would find the way blocked to pass from a host to another through skin.

But soon men offered them a new way of transmission that the microorganism found even more comfortable and easy than the previous one: genital mucosas.

Sexual promiscuity and the traffic of pathogens linked to the movement of large masses such as armies always looking for sexual pleasures.

Armies and syphilis

They offered the Spirochaeta how passing from a host to another through genital mucosas[1] which were certainly less resistant than skin may be. The rapid movement of multitudes of carriers together with the length of the disease and of the patient caused Syphilis to be spread all over the world.

Syphilis

The” moderate” character and the long lasting of an infection, both bacterial and viral, occur after a long adaptation between host and microparasite. In this case we can think the adaption between man (host) and Spinochaeta (microparasite) took place in the long period in which this disease showed as Framboesia.

[1] Mc Neill W H, Plagues and peoples. Op.cit. Pag. 193

[1] Myers G, Maclnnes K and Myers L. Dual cross-species transmission.pag.130-1 In Emerging Viruses. Op.cit.

[2] Mc Neill WH.Plagues ans peoples. Pag. 41-2 Anchor Book Doubleday New York 1989.

plagues and peoples

Translated from “Il Virus Intelligente” by Enrica Narducci

To be continued in:

1) The trans-species jump from the animal reserve  (2° part)