TUESDAY MARCH 13 2001

Foot-and-mouth

US researchers seek vaccine on isolated island

FROM JAMES BONE IN PLUM ISLAND, NEW YORK

THE best hope for a rapid-acting vaccine to halt the spread of foot-and-mouth disease may lie on a tiny speck of land off the furthest tip of New York’s Long Island.

The research centre on Plum Island, 840 acres of low-lying woodland, is the sole laboratory in the United States permitted to experiment with the live foot-and-mouth virus. Only authorised personnel can board the small ferry for the 15-minute crossing to the Agriculture Department’s Animal Disease Centre. Just to get into their labs scientists must undress completely, removing even their spectacles and wedding rings, and walk naked into the area of negative air pressure in which they work. It ensures that any pathogens are sucked inwards.

For a quarter of a century Marvin Grubman, the centre’s leading research scientist, has been working on a new vaccine. Although a vaccine has existed since the late 1940s, it is made from a chemically inactivated virus, which could cause the disease. The Isle of Wight outbreak in 1981 is thought to have been caused by virus from France that was linked to poorly inactivated vaccine. As a result mass vaccination has not been attempted in Western Europe since 1992.

The current vaccine is also considered to be too slow-acting to stop the proliferation of the disease since vaccinated livestock, while unaffected, can still carry the virus. As a result countries respond to outbreaks by slaughtering infected herds.

In recent years, however, Dr Grubman and his colleague Peter Mason have been developing a new genetically engineered vaccine that cannot cause disease and which could quickly stop livestock “shedding”, or communicating, the virus. “I think we are making great progress,” Dr Grubman said.“That’s not to say we are going to have a product next week, or next year or in the next five years.” Because the disease spreads so fast, the aim is to make a vaccine effective within two days, but seven days is the best result thus far.

The research is trying to create a vaccine that incorporates only the genetic code of the empty husk (capsid), of the virus. The hope is that vaccinated animals will recognise the capsid and produce antibodies to defend against it. Rival scientists in Spain and elsewhere are trying a similar approach, but Dr Grubman believes his team has gone one better by incorporating the genetic information for a key enzyme needed to disassemble the capsid.

At the insistence of Congress the foot-and-mouth lab was located on an island. Plum Island has its own water, sewage and electrical systems. All rubbish is incinerated or heat-treated and left in quarantine for seven days before being tested.

It is proof of the virulence of foot-and-mouth disease that, even with these stringent precautions there was an outbreak on the island in 1979, during building work. Luckily for US farmers, the disease did not spread to the mainland. The scientists on Plum Island have one further, natural, protection: the prevailing winds blow eastwards, towards the Atlantic.