As we come to grips with our first suspected cases of SARS, Kathryn Holmquist asks how and why the disease could cause a pandemic similar to the Black Death
A middle-aged Co Mayo man who recently returned from Hong Kong is today in hospital in Castlebar with what the Western Health Board describes as a "probable" case of severe acute respiratory syndrome (SARS). The man is showing all the signs of the syndrome and he had been in close contact with Hong Kong locals who may be carrying the virus. It is understood that he visited the Metropole Hotel in Kowloon, the epicentre of the outbreak.
While the man is not seriously ill, he has been placed in isolation in Mayo General Hospital to protect the public from the spread of the disease.
However, public health doctors nationally will be unavailable to deal with this case or any new cases this weekend, due to their work to rule over a pay claim. Leaving any cases in the hands of local hospitals.
Two previous suspected cases of SARS in Dublin have been discounted. Last Sunday, an Irish citizen returning from the Far East with flu-like symptoms turned up in the casualty unit of St James's Hospital having read about Severe Acute Respiratory Syndrome (SARS) in a newspaper. The World Health Organisation had issued its first alert since 1997, warning of the spread of SARS from south-east Asia and urging the need for "absolute continued vigilance".
The syndrome - whose pathogen is yet to be determined, but which is airborne - causes fever, chest problems and a blood disorder. It is believed to be contagious only in situations of close contact. Most of those infected are believed to be either family members or health care workers who had close contact with the disease.
At last count, it was confirmed SARS had claimed 10 lives and further fatalities are suspected. Some 350 people are described as seriously ill with the disease.
When the first suspected case appeared here, public health doctors in the State immediately took action, sharing information with the WHO (World Health Organisation) and the CDC (Centres for Disease Control) in Atlanta, Georgia as the patient was put in isolation and treated by medical staff wearing protective clothing, masks and gloves. A few days later, a second Irish citizen returning from the Far East appeared in casualty at Beaumont hospital with the same symptoms and received similar treatment.
The Minister for Health, Micheál Martin set up an expert committee to investigate this syndrome and its management, joining with the Eastern Regional Health Authority (ERHA) and the National Disease Surveillance Centre (NDSC) in what one communications officer called "a three-way tennis match".
The committee comprises ERHA and NDSC public health doctors - 300 of whom are currently on a work-to-rule following a 10-year dispute with the Department but who nevertheless worked hard during the week to investigate the three suspected cases of SARS. They have also given fair warning that they plan to give one week's notice of an all-out strike in two weeks' time in their attempt to improve their pay and work conditions.
The SARS alert has occurred against a background of feared bioterrorist attack, which has public health doctors in the State and around the world watching vigilantly for any mysterious new syndrome.
The WHO sees SARS as one of seven pathogens with the potential to cause the next Black Death. Investigation of SARS is going on "at top speed, in top labs", it says, as public health experts attempt to avert a pandemic.
Experts worldwide agree there is no doubt that there will be another plague, the only question is when. The pandemic is expected to come from south-east Asia and public health doctors will be the cavalry.
"We keep a watching brief, and whenever we see a novel syndrome, where we don't know how it is spread or what the pathogen is that caused it or how to treat it, there is a real concern amongst public health doctors," says Dr Paul McKeown, a specialist in public health medicine with the NDSC.
In what the WHO calls "an outstanding example of detective work", epidemiologists have determined that seven people who contracted SARS recently stayed in or visited the Metropole Hotel in the Kowloon district of Hong Kong last month. The seven people investigated include three visitors from Singapore, two from Toronto, Canada (both of whom died subsequently), one China mainland visitor, and a local Hong Kong resident.
The investigation revealed that all seven stayed in or visited the same floor of the hotel between February 12th and March 2nd. The local Hong Kong resident is believed to be the first known carrier,and he subsequently infected others. He had visited an acquaintance staying at the hotel from February 15th to 23rd. The visitor from mainland China, who became sick a week before staying at the hotel, is considered the original source of the infection. No further cases have been linked directly to the hotel.
Twenty years ago, SARS would have "rumbled on" without detection, until it was too late, says Dr McKeown.
Today's intricately linked public health systems, from Hong Kong and Japan, to Germany and Atlanta, hope to act within days, rather than years, of a new plague's appearance.
SARS is of particular concern because it has a mortality rate of 3 per cent - which means that for every 10 million people infected, 300,000 would die.
The organisms that cause pandemics, such as the Black Death in the 15th century, exploit the same vulnerabilities that bioterrorists seek to target, says Dr McKeown. "The bug doesn't care who distributes it. Whether it's the good Lord or a terrorist, we need the same systems to detect a deliberate release as we do to detect a natural release. These agents are not yet preventable, our only defences are strong early warning and surveillance systems."
The world's first known case of bioterrorism occurred in 1380, during the Black Death - when the town of Kaffa, in present day Crimea, was under siege by Mongols who threw plaque victims over the city walls.
Genoese merchants carried the plague to Europe. It took them four months to get to Italy, and by the time they arrived, most were dead and those who survived were in the highly infectious stage having developed buboes (inflamed lymph glands).
Today's equivalent of the Genoese merchant is the infected business traveller, emigrant or tourist who takes a mere seven hours to travel between continents, rather than four months. Potential plague pathogens can exploit this, springing up almost simultaneously in several locations around the world and capable of destroying humanity.
In 1918, 40 million people died in the Spanish flu epidemic and since then there have been influenza epidemics in 1957 and again in 1997 when the Hong Kong influenza pathogen (HVN1) was held off only by the slaughter of millions of chickens carrying the virus. In 1999-2000 there was a panic in New York City when 24 people were killed by the West Nile virus.
The West Nile virus can teach us a lot about the emerging infectious diseases, such as SARS, with the potential to create a pandemic. West Nile fever, which infects the membrane lining the brain, is an emerging disease. It started in Uganda in 1937 as a mild childhood illness, but by 1957 had become virulent in Israel. In the 1960s it began to affect horses, then humans, in Europe.
West Nile fever has been created in a kind of human petri dish, and the conditions for its growth are poverty, squalor, poor health care, poor education, close proximity of humans and animals and wet warm weather. These same factors exist in southern China, where SARS has emerged.
Mosquitoes transmit the pathogens from animals to humans and back again, with each mutation hoping to defeat immune systems, antibiotics and vaccines. Birds, horses and monkeys have so far been identified as ideal cultures for such pathogens capable of defeating the human race.
Such a virus or bacterium needs only one vulnerable human cell in one human body to begin its existence. Such organisms divide at an incredible rate (salmonella divides once every 20 minutes) and with each division comes the risk of mutation.
Viruses turn normal human cells into Trojan horses, taking them over and then changing their structure.
The difficulty for public health doctors is that the horse constantly changes colour, due to the remarkable ability of the virus to change its identity, making the pathogen harder to find.
Added to this challenge is the fact that many antibiotics are now useless against infections which have developed resistance.
It's Darwinism at its most basic, as the fittest pathogens survive antibiotics, then reproduce even more vigorously, intensifying their own power.
Demographics have given pathogens even greater opportunities to exploit humanity. The world's population doubled in the 20th century and whenever people live closer together, there are more diseases - as seen in the massive upsurge of cholera, typhoid and TB in the 1820s and 1830s during the industrial revolution.
Public health systems are the only defence, and the deterioration of New York City's system in the 1980s is now seen as directly responsible for the rise there of antibiotic-resistant TB. After the fall of the Soviet Union, tens of thousands of Russians died of diphtheria because vaccination programmes had ceased.
Migration allows such pathogens to cross continents with ever increasing frequency and as if this weren't enough, there's the impact of the destruction of natural habits by human beings.
Deforestation disrupts natural habitats and brings people and animals closer together, allowing diseases such as Lassa fever, Yellow fever, Ebola, Rift Valley fever, West Nile fever and Lyme Disease spread more easily from animals to humans.
Global warming has meanwhile encouraged more and more mosquito-carried illness, such as Japanese Encephelitis which is endemic in Papua New Guinea. "Our biosphere is an interconnected entity," says Dr McKeown.
To avoid such illnesses, Dr Laffoy advises: wash your hands, especially after contact with anyone sneezing or blowing their nose. If you're worried, go to your local casualty department.