Polio has been wiped out in 155 nations, including all of
North and South America, China and Australia. However two new cases have
recently been diagnosed in Bulgaria. These are the first cases in Europe since
1998. The virus was found in a 13-month-old baby, a Gypsy in the Black Sea city
of Burgas, had the virus, the WHO said. Other children in the community of
Gypsies, also known as Roma, were immediately vaccinated. On May 15, the same
virus was identified in a 2-year-old Gypsy child in the city of Yambol, 60 miles
west of Burgas, health Bulgarian officials reported. The conditions of the
ailing children were not disclosed. Laboratories in Paris, Rome and Atlanta
studied the virus and traced it to northern India, according to a statement from
WHO's European region headquarters in the Danish capital. "The fact that
the virus was imported from India shows how just how important worldwide
vaccination campaigns are,'' WHO spokesman George Oblapenko said. "Without
constant vigilance, Europe's polio-free status and the global eradication
efforts would both be in danger.'' A vaccination campaign announced after the
cases were disclosed was delayed because there were no vaccines in the country.
A Bulgarian Health Ministry official said about 800,000 doses of polio vaccine
were due to be imported within days. "The funding gap is the most critical
inhibitor to a successful eradication at this point in time,'' Melgaard said.
Polio is a highly infectious disease that usually strikes children younger than
5, damaging the spinal cord and brain, causing paralysis and sometimes death. It
is transmitted by ingesting food or water contaminated by fecal matter of an
infected person.
The good news is that the worldwide count of Polio has hit an
all time low. "We have forecast that by the end of this year, less than 10
countries will remain endemic for polio virus and within two years, we will be
down to zero," said Dr. Bjorn Melgaard, director of vaccines and
biologicals at WHO. "We already may have eradicated one of the three virus
types causing polio," Melgaard said. The type II polio virus was last
detected in October 1999; experts say that after a year of silence, a virus type
usually is considered to have died out. Type II is far more likely to lead to
paralysis than other polio virus types, said Dr. Bruce Aylward, coordinator of
WHO's polio program. While the two other types give polio-infected children a
1-in-1,000 and 1-in-200 chance of becoming paralyzed, type II paralyzes about
one in every 100 children it infects, he said. The eradication initiative is a
joint project of WHO, the U.N. Children's Fund, Rotary International, and the
U.S. Centers for Disease Control and Prevention. It aims to certify the world
polio-free by 2005. The effort, launched in 1988, was intensified in 1999. The
number of WHO staff working in polio-stricken countries swelled from 200 in 1999
to about 1,600 in 2000. There were more national immunization days, and health
workers went door-to-door with vaccines. Since the effort to eradicate polio
began, cases have fallen from 350,000 in 1988 to 2,870 in 2000, a reduction of
99 per cent. "In India, we are certainly very, very close,'' Melgaard said.
"In 1998 nearly 2,000 cases were identified, basically all over the
country. In 1999 this got more concentrated to the very populous states. In
2000, only 265 cases were reported and so far this year, with an extremely
top-notch surveillance system, only 10 cases have been reported.'' However, WHO
officials said it will take another $400 million to stamp out the disease, which
still lurks in Southeast Asia, the eastern Mediterranean and Africa.
On the research front, scientists have found a way to use the
polio virus to actually help people. A hybrid of the virus that causes polio and
the virus that causes the common cold could eliminate the most common type of
brain cancer. Injecting the hybrid virus into mice with malignant glioma, the
most common kind of brain tumor, resulted in complete recovery after one dose,
researchers said. "We have generated a virus that is unable to cause
disease in the brain but that still has the ability to infect and destroy brain
tumor cells,'' Matthias Gromeier, an assistant professor of microbiology at Duke
University, who led the research team, said in an interview. Results from the
ongoing study, already in its seventh year, were presented at a meeting of the
American Society for Microbiology in Orlando, Florida. Poliovirus, which can
cause brain infections in humans, naturally seeks out brain tumor cells because
they carry a specific binding molecule. This molecule, known as CD155, is not
found in healthy brain cells and isolates the virus in cancerous cells. But
because poliovirus also causes polio, which can lead to permanent paralysis and
sometimes death, researchers needed to disable the virus's destructive
capabilities. "It is a somewhat unusual proposal that we are making because
the virus that we are basing our treatment on is a potentially dangerous,
infectious agent,'' Gromeier said. "If you want to propose using any kind
of virus for therapy purposes, you have to make sure that this virus can no
longer cause disease.'' "We genetically engineered a poliovirus variant
that lost its ability to cause disease in humans. We accomplished this task by
inserting a piece of genetic information of rhinovirus (the virus that causes
the common cold) into the poliovirus genome," says Gromeier. "The
mixed polio/rhinovirus construct had very surprising properties: it had lost its
ability to cause poliomyelitis in humans, but retained excellent killing
potential for malignant glioma cells."
