Section D This section consists of one passage
followed by a summary. Read the passage carefully and complete the summary below
by choosing no more than three words from the passage for each blank. Remember
to write the answers on the answer sheet. Questions 61 to 65 are based on the following
passage.
A 19th Century Killer Disease: Tuberculosis
In 1882, Robert Koch, a German country doctor, succeeded in isolating the
bacillus of tuberculosis. This discovery came at a time when this disease was
the greatest single killer of the human race. All during the
19th century it had spread remorselessly with the growth of cities, until it had
reached epidemic proportions throughout the industrialized world.
Its record in the United States was one of frightful devastation.
Immigrants from Europe, many of them debilitated from famines at home, flooded
into the poorest and dirtiest sections of cities, there to die of the disease by
the thousand. Working children were infected in staggering numbers. Hundreds of
thousands of children worked twelve hours a day, six days a week. Chronically
exhausted and undernourished, they made particularly susceptible victims. Since
tuberculosis was not considered contagious, its victims spread the disease
amongst those about them as they coughed, spat and drank from communal
cups. It is now known that tuberculosis is chiefly spread by
droplet infection. It can also occur as a result of drinking unpasteurized milk
from tubercular cows, where the pathogen penetrates the body through the
alimentary canal. However, entry of the bacillus into the body is not
necessarily followed by a clinical illness, the development of which depends on
several other factors. Many people, for instance, seem to have a high natural
resistance and although acquired immunity is not fully understood, it has been
proved that if a person contracts and recovers from a primary tuberculosis
infection, he is less likely to develop active tuberculosis on subsequent
exposure to the tubercle bacillus than a patient who has not previously been
infected. Tuberculosis has notoriously been associated with
poverty, with its accompanying malnutrition, overcrowding and stress, and while
the exact role of nutrition is uncertain, it seems that a diet based on cheap
carbohydrate and a lack of protein and vitamins is another contributing
factor. In addition, a condition such as diabetes mellitus also
leads to increased risk of developing the disease, and statistics from certain
mining areas in Africa show that sufferers of respiratory disorders, such as
silicosis, are especially vulnerable to attacks of pulmonary
tuberculosis. The introduction of mass immunization against TB
by the use of BCG vaccine, and of mass radiography, where it is possible to
screen large numbers of people for early signs of tuberculosis, has dramatically
reduced the incidence of the disease in the last few decades. Summary : Despite the fact that
tuberculosis was the number one killer in the 19th century, it was not proved
that the disease was (61) until 1882 when Robert Koch
succeeded in isolating the tubercle bacillus. While it is now well known that
tuberculosis is spread by (62) infection, it is also evident
that entry of the tubercle bacillus does not necessarily lead to development of
the disease. Although we do not yet fully understand (63) ,
there is evidence to show that a person who has contracted and recovered from
the disease is (64) likely to develop active tuberculosis on
subsequent exposure to the bacillus than a patient who has not been previously
infected. As with all diseases spread by droplet infection, living in
overcrowded insanitary conditions greatly increases the risk of (65)
.