Emerging Viruses 3°
Psittacosis
Among the emerging viruses the most suitable example to our case is the Psittacosis one, an infective disease caused by viruses which are present in parrots. Till 1929 the disease was very rare, then in 1929-30 there was a sudden explosion of cases, contemporaneously, both in Europe and in North America. It was scientifically proved that the epidemic was connected to the import of parrots from South America to Europe and to North America where many new cases[1] occurred.
Also here, therefore, as it was for HIV, there are two comporary focuses, both of them linked to the import of living animals from zones where the disease is endemic.
Some more reserves of viruses of psittacosis were found out of the orders of psittaciformes and precisely in the petrel glacial, a bird of the Faroe islands in the North Atlantic Ocean[2].
The inhabitants of these islands would feed, abundantly, on the chicks of these birds. Those who paid for this human activity were, in September 1933, the women of the Faroe islands who would pluck the petrels inside their houses.
The epidemic affected 71 people in all, mostly women, with 8 dead persons. In this case there are even three nearly contemporary focuses of the disease in places which are very far from one another.
The only reserve of the virus wasn’t the one of the psittaciforms but many more were found out in different species of birds; in the same way it wasn’t only one viral type to carry out the trans-species jump during the period of epidemic.
Besides the psittacosis one there were other very similar, even if not identical, viruses which emerged from the animal reserve in the same period and adapted themselves to invade man.
Particularly viruses, similar but not completely to the one of psittacosis, had passed to man from pigeons as well as from many other species of birds like the Budgerigar which is bred in California for commercial purposes.
In order to include, in only one denomination, all the viral diseases caused to man by viruses coming from birds( included the one of psittacosis) Meyer invented the word Ornithosis. Epidemics of ornithosis occurred, contemporaneously, in different focuses and far from one another.
This can give us an idea about the multiplicity of the viral types which carried out the trans-species jump contemporaneously.
But, why did the focuses of psittacosis remain limited in time and places of origin unlike AIDS epidemic spreading everywhere and more and more flourishing?
First of all even if ornithosis can pass from man to man only when the latter is very sick, it can spread the infection. This doesn’t happen when man can still cohabit with the general community. In the case of HIV most contagions occur when a seropositive is apparently sound and this condition lasts a lot of time.
Translated from “Il Virus Intelligente” by Enrica Narducci
To be continued in:
4)Emerging Viruses 4°
5)Emerging Viruses 5°
6)Emerging Viruses 6°
See also:
2) Emerging Viruses 2°
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