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BART ROMBAUT AN. R. ACAD. NAC. FARM.

The ultimate cleavage products are the four structural proteins
(called VP1-4) destined to build the protein capsids of the virions
plus half a dozen nonstructural proteins, several which are known to
possess enzymatic activities (3).

Poliovirus has three different serotypes and is belonging to the
enterovirus genus, one of the six genera of the picornavirus family (4).

HISTORY OF POLIOLMYELITIS

Polio is not a new disease! Poliomyelitis is in fact known for
more than 3,000 years. An Egyptian limestone stele (1350 B.C.)
exhibited in the Glyptotek Museum in Copenhagen portrays the
priest Rem giving offerings to the Godess Astarte. The man has a
thin, withered leg, widely believed have been caused by poliomyelitis.
The ancient Greeks were also cognisant of the disease, for instance
Hippocrates described paralysis that afflicted patients predominantly
in summer and autumn, i.e., the period that has been considered
as the «polio season» (6). In archaeological excavations in southern
Greenland, 24 skeletons from the 15th century were discovered, which
showed bone deformities reminiscent of those typically associated
with severe poliomyelitis. These examples ascertain that occasional
cases of poliomyelitis have occurred throughout the history of
mankind. On the other hand, the scarcity of the reports indicates
that the manifestations of poliomyelitis were rare, and that the
disease did not often occur in an epidemic form (7).

The epidemiological picture of the disease changed dramatically
in the late 19th and, early 20th centuries. The first epidemics occurred
in Northern Europe and the U.S.A. These epidemics grew in size,
frequency, and severity. In 1889, the first recorded poliomyelitis
epidemic has been experienced in Stockholm (Sweden), afflicting
44 persons. By 1916, no fewer than 27,000 cases of poliomyelitis
have been recorded in the U.S.A. alone. During the first 3 decades
of the 20th century, 80-90% of poliomyelitis victims were under
5 years of age, with the majority of patients afflicted during the first
2 years of life. Therefore, the disease was often termed «infantile
paralysis». It became as dreaded as the plagues of the middle ages.
In areas which had suffered repeated epidemics, a shift in the age of

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