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Vol.
XXVII No. 20
May 18,
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SARS:
How Much of a Threat?
Amit
Sen Gupta
THE
SARS (Sudden Acute Respiratory Syndrome) epidemic has struck fear in country
governments, practitioners and whole populations across the globe.
It has made global headlines and seems to have even overshadowed the
human tragedy that is unfolding in Iraq. While we debate on how large a threat
SARS is we should not lose sight of the fact that, till
the beginning of May, there have been 5,600 reported cases and 372 deaths due to
the epidemic. Contrast this with over 2,000 or almost six times the number of
deaths taking place in India alone in a single day due to Tuberculosis.
Further, in this one day 3,500 people would die of Malaria, most of them
children in Africa. How the SARS epidemic will progress is open to speculation,
as is the question how large a public health threat SARS will be in the future.
What we do know is that it is a new infection, which can be extremely virulent,
and can cause deaths in over 5 per cent of those who are infected. While SARS
needs to be tackled with caution and speed we should also not lose sight of the
fact that influenza epidemics caused by mutant starins (also caused by the same
family of viruses called coronavirus that causes SARS) have been known to appear
suddenly, cause a large number of deaths, and then lose steam.
How
such epidemics appear suddenly is explained by the capacity of viruses to mutate
that is to change their genetic characteristics. The human body, when infected
by a certain virus, fights the virus by producing what are called antibodies
against the infection. These antibodies remain in the system and confer partial
or total immunity against subsequent infections by the same virus. Thus, if a
virus has been around for a long time, most of the people in the community have
some form of immunity against the virus – like immunity against the common cold.
So even if infections occur, they are not very serious and such viruses do not
cause epidemics. This phenomenon, where most people in a community have immunity
to a certain disease-causing germ is called herd immunity. In the case of
a new mutant virus, such herd immunity does not exist. As a result the disease
is able to spread and assume epidemic proportions. Over time, as more people get
infected, herd immunity develops in the community and the epidemic dies down and
the disease expresses itself as isolated cases.
WHAT
IS
SARS?
Lets
us now turn to what we know about the epidemic. In November, 2002, an outbreak
of atypical pneumonia (i.e. pneumonia that is not caused by known causative
organisms and has atypical features) was reported in Guangdong province in
southern China. In late February, 2003, such cases were first reported outside
China, in Hanoi, Vietnam. In March, 2003, a WHO officer Carlo Urbani first drew
global attention to the outbreak after examining cases in Vietnam and coined the
name sudden acute respiratory syndrome or SARS. Carlo Urbani himself died of the
infection within 3 weeks of his drawing the worlds attention to the epidemic.
We
know now that the illness caused by SARS usually begins with a fever, sometimes
associated with chills or other symptoms, including headache, general feeling of
discomfort and body aches. After 2 to 7 days, SARS patients may develop a dry
cough that might be accompanied by or progress to the point where insufficient
oxygen is getting to the blood. In 10-20 per cent of cases, patients will
require mechanical ventilation with a machine. The incubation period (i.e. the
period between the time of infection and the manifestation of symptoms) is
typically 2 to 7 days though isolated reports have suggested an incubation
period as long as 10 days. SARS is spread by close person-to-person contact
including through touching the skin of other people or objects that are
contaminated with infectious droplets and then touching ones eye(s), nose, or
mouth. This can happen when someone who is sick with SARS coughs or sneezes
droplets onto themselves, other people, or nearby surfaces. People are most
likely to be infectious (i.e. capable of infecting others) when they have
symptoms, such as fever or cough. However, it is not known how long before or
after their symptoms begin that patients with SARS might be able to transmit the
disease to others.
We
also know now that SARS is caused by a previously unrecognised coronavirus.
Coronaviruses are a group of viruses that have a halo or crown-like (corona)
appearance when viewed under a microscope. These viruses are a common cause of
mild to moderate upper-respiratory illness in humans and are associated with
respiratory, gastrointestinal, liver and neurological disease in animals.
These viruses do not last a long time outside the body – generally not
more than three hours.
Several
new laboratory tests can be used to detect the SARS-associated coronavirus (SARS-CoV).
These include the detection of antibodies to the virus in the patients blood,
detection of DNA of the virus in samples taken from the patients blood,
sputum, etc and culture of the virus. All these tests are expensive and they are
not always conclusive. So the diagnosis of SARS depends on a combination of such
tests, identifiable symptoms in the patient, and a history of contact with
someone known to have SARS.
GLOBALISATION
AND
SARS
The
SARS epidemic and its subsequent handling, curiously, points to both the threats
posed by globalisation and its potential advantages. Globalisation
leads to transnationalisation of public health risks. A major effect, in
recent years, has been the resurgence of communicable diseases across the globe
– the most recent expression being SARS. Every phase of human civilisation that
has seen a rapid expansion in exchange of populations across national borders
has been characterised by a spread of communicable diseases. The early settlers
in America, who came from Europe, carried with them small pox and measles that
decimated the indigenous population of Native Americans. Plague travelled to
Europe from the orient in the middle ages, often killing more than a quarter of
the population of cities in Europe (like the plague epidemic in London in the
fifteenth century). This is a natural consequence of exposure to local
populations to exotic diseases, to which they have little or no natural
immunity.
Today,
what incubates in a tropical rainforest can emerge in a temperate suburb in
affluent Europe, and likewise what festers in a metropolitan ghetto of the
global North can emerge in a sleepy village in Asia – within weeks or days. The
SARS epidemic, for example, which started from China, may have festered in its
place of origin and run out its course if the rapid exchange of people across
countries had not taken place. When such rapid spread takes place, those that
are most badly affected are the poorest that live in developing countries,
because their immunity is compromised by under nutrition and because they have
little or no access to health facilities. We must not forget the backdrop-in the
last twenty years IMF/WB mandated policies have devastated public health
facilities in virtually every developing country. It is a moot point whether
this epidemic would have reached current proportions if China had not chosen to
drastically privatise its health facilities in the last decade. In fact
Chinas privatisation of the Health Sector, today, is almost as widespread as
in India.
In
the 1960s scientists were exulting over the possible conquest to be achieved
over communicable diseases. Forty years later a whole new scenario is unfolding.
AIDS is its most acute manifestation. We also have resurgence of cholera, yellow
fever and malaria in Sub-Saharan Africa, malaria and dengue in South America,
multi-drug resistant TB, plague, dengue and malaria in India. We also see the
emergence of exotic viral diseases, like those caused by the Ebola and the Hanta
virus and now SARS. We thus have a resurgence of old diseases compounded
by the emergence of new ones. Globalisation
that forces migration of labour across large distances, that has spawned a huge
market on commercial sex, that has changed the environment and helped
produce freak microbes, has contributed enormously to the resurgence. We
talked of the random mutations that produce new viruses. The pace of such
mutations is increasing due to environmental degradation as microbes are exposed
to hitherto unknown conditions.
RESPONSE
OF THE
SCIENTIFIC
COMMUNITY
The
response of the global scientific community to the SARS epidemic also points to
the potential that true globalisation has in tackling human misery. In 2001, the
World Health Organization (WHO) established an epidemic alert and response
programme to enable coordinated responses to emerging epidemics, and in early
March of this year, the WHO used this program to start an international
collaborative investigation into the nature of SARS.
The results of this international collaboration have been the
astoundingly rapid identification of a likely etiologic agent (i.e.
identification of the virus that causes SARS) and the dissemination of clinical
information with unprecedented speed. The information already gleaned about the
SARS virus will help in the development of an accurate diagnostic test and
antiviral drugs. A speedy test could be available soon, according to the WHO,
which coordinated the work of 13 laboratories around the world. The pace of
SARS research has been outstanding, said Dr David Heymann, WHOs executive
director of communicable diseases. The work of the laboratories and WHO has been
dedicated to Dr Carlo Urbani, the WHO scientist who first identified the virus
in Hanoi and subsequently died of SARS.
The
speedy response to SARS shows what can be achieved by global scientific
collaboration. It also shows that such collaboration is manifest today only when
the developed world sees a threat to its own population. The potential exists,
but under imperialist globalisation this potential is fettered by the narrow
interests of developed countries. Why else have we not seen such a high degree
of collaboration when it comes to diseases that continue to plague the
developing countries – like Malaria or Tuberculosis.
COMIC
SPECTACLE
IN
INDIA
The
handling of the threat of a SARS epidemic in the country has been typically
inept. We see a comic spectacle unfold before us as the Indian government
blunders along. First there was a flurry of positive SARS cases reported
from across the country. We were told that these cases had been confirmed
by the National Institute of Virology. Then, suddenly, Mrs Sushma Swaraj
gleefully announced that we had been mistaken all this while because the WHO now
says that none of these confirmed cases are actually cases of SARS. Did we
require the WHO to tell us this? The WHO has no surveillance, treatment or
diagnostic facilities in the country. It relies on data provided by the Indian
health authorities. How is it that the same data told two entirely different
stories? It is obvious that the handling of the suspected cases ignored standard
practices, which any competent medical practitioner should be aware of. If the
National Institute of Virology (NIV) had confirmed cases, how did they
suddenly turn out to be SARS free after the WHO declared them to be so? It is
clear that what the NIV had declared as confirmed were not confirmed cases. The
NIV had not followed standard protocol – now available globally and even
accessible to anyone who has access to the internet – while labelling cases to
be SARS positive.
If
we can misdiagnose patients as SARS positive we are equally capable of
misdiagnosing patients as SARS negative. In other words, we are by no
means geared to tackle the SARS epidemic if and when it reaches India.
Epidemic control is not achieved by holding press conferences and
stationing masked doctors at airports. Epidemic control requires a high level of
preparedness of the public health infrastructure. This infrastructure has been
systematically dismantled in the last 12 years of economic liberalisation. The
government has taken the lead in delegitimising this infrastructure and today
very few people have faith in the public health system. In such a situation do
not expect SARS cases to be detected and treated by the public health system. We
can only hope that the doddering edifice of our public health infrastructure is
not called upon to deal with a real SARS epidemic. If that happens, it is doomed
to fail.
