AT long last, a different kind of dry season offensive is underway in the Northwest.

Children living in areas controlled by Khmer Rouge breakaway factions are being targeted

for the first time in a nationwide vaccination campaign against poliomyelitis.

Part of a three-year push by the Ministry of Health and the World Health Organization

to eradicate polio in Cambodia, they hope this year's National Immunization Days

(NIDs) - Feb and Mar 11 - will be the last.

"If Cambodia's 1997 NIDs are as successful as those of 1995 and 1996, and if

efforts to reach pockets of missed children are equally successful, the Ministry

of Health anticipates that there will be no more Cambodian children infected by poliomyelitis

after 1997," a Ministry of Health statement said.

According to health officials, because of the complicated logistics of reaching under-fives

in the former war zones, the first round of NIDs has already been launched in four

districts of Battambang province: Pailin (Jan 28), Kamreang (Jan 29), Phnom Prek

(Jan 30), and Sampov Lung (Jan 31).

At press time, Second Prime Minister Hun Sen was due to go to Phnom Malai for tomorrow's

launch of the NIDs.

NIDs will be launched in Samlot on Sunday, health officials said.

Government health workers, mobile teams, and trained volunteers have been deployed

to administer the oral polio vaccine to an estimated 13,975 children in the five

Battambang districts, and to 3,000 in the Malai district of Banteay Meanchay province,

said Ly Nareth, director of the Ministry of Health's poliomyelitis eradication unit.

The aim of the two Immunization Days which will occur at a monthly interval, according

to Dr David C Bassett of WHO, is to deny the polio virus a human host by providing

blanket coverage.

"The wild virus has only one known host and that is a human being," he

said.

"If the wild virus is circulating in the environment and cannot find a human

host then in two to three weeks it will die."

So far, the 1995 and 1996 NIDs achieved high coverage - at least 90 percent in both

years - helping to dramatically reduce the number of clinically diagnosed cases of

polio in Cambodia, but there is room for improvement, health officials said.

In 1994, according to Bassett, Cambodia was the most polio stricken country in WHO's

Western Pacific Region. In 1996, approximately 1.8m children were taken to vaccination

posts nationwide in both rounds.

As a result, the current number of 1996 confirmed cases of polio is down to 50.

Health officials, however, have come to identify the weakness in their strategy to

reach all susceptible populations, particularly those living in formerly insecure

areas and remote pockets, or those that move along Cambodia's intricate network of

waterways.

"In our work in 1994, '95, and '96 we have been learning a lot," said Bassett.

"We have learned, for instance, that even if you get 90 percent coverage, obviously

it means that you're still missing ten percent.

"We recognize now that there are populations of children who are being chronically

missed," he added. "We've got to reach those children if were going to

eradicate polio."

To close the gap, a new component is being added to this year's NIDs: 461 mobile

teams that will fan out across the country on-board boats and motorbikes.

Health officials also admit that if indeed the 1997 blitzkrieg against polio is to

be the last, they are going to have to beat the clock.

"If at the end of the month we have not eliminated all of the virus - and we

know that so far we have not - then that gives the virus 11 months to re-establish

itself," Bassett said.