Read the given passage and answer the following questions:
Bacteria like Streptococcus pneumoniae and Haemophilus influenzae are responsible for the disease pneumonia in humans which infects the alveoli (air filled sacs) of the lungs. As a result of the infection, the alveoli get filled with fluid leading to severe problems in respiration. The symptoms of pneumonia include fever, chills, cough and headache. In severe cases, the lips and finger nails may turn gray to bluish in colour. A healthy person acquires the infection by inhaling the droplets/aerosols released by an infected person or even by sharing glasses and utensils with an infected person. Dysentery, plague, diphtheria, etc., are some of the other bacterial diseases in man. Many viruses also cause diseases in human beings. Rhino viruses represent one such group of viruses which cause one of the most infectious human ailments – the common cold. They infect the nose and respiratory passage but not the lungs. The common cold is characterised by nasal congestion and discharge, sore throat, hoarseness, cough, headache, tiredness, etc., which usually last for 3-7 days. Droplets resulting from cough or sneezes of an infected person are either inhaled directly or transmitted through contaminated objects such as pens, books, cups, doorknobs, computer keyboard or mouse, etc., and cause infection in a healthy person.
The passage explains how pneumonia spreads from an infected person. Mary Mallon, nicknamed ‘Typhoid Mary’, is a classic case in medicine because she:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → was a cook and a typhoid carrier who spread typhoid through the food she prepared
Typhoid fever is caused by the bacterium Salmonella typhi. The pathogens usually enter the small intestine through food and water contaminated with them. A carrier is a person who has the pathogen and passes it on to others. Mary Mallon was a cook by profession and a typhoid carrier, so she kept spreading typhoid for several years through the food she cooked. Her case shows how a carrier spreads a disease carried by food.
Option (1) was a cook and a typhoid carrier who spread typhoid through the food she prepared — Correct. Mary Mallon was a cook and a typhoid carrier. The bacteria reached other people through the food she prepared, which is the usual route of typhoid.
Option (2) was the first patient whose typhoid fever was confirmed by the Widal test — Incorrect. The Widal test is used to confirm typhoid fever, but the book does not connect Mary Mallon with this test. She is remembered as a carrier who spread the disease.
Option (3) caught typhoid by inhaling droplets released by an infected person — Incorrect. Inhaling droplets released by an infected person is the route of pneumonia and the common cold, as in the passage. Typhoid spreads through contaminated food and water.
Option (4) developed intestinal perforation from typhoid but recovered without treatment — Incorrect. Intestinal perforation is a sign of severe typhoid that may lead to death. The book does not say this about Mary Mallon; her story is about spreading the disease.
NCERT Extract:
Common Diseases in Humans – “… Salmonella typhi is a pathogenic bacterium which causes typhoid fever in human beings. These pathogens generally enter the small intestine through food and water contaminated with them and migrate to other organs through blood. … Intestinal perforation and death may occur in severe cases. Typhoid fever could be confirmed by Widal test : A classic case in medicine, that of Mary Mallon nicknamed Typhoid Mary, is worth mentioning here. She was a cook by profession and was a typhoid carrier who continued to spread typhoid for several years through the food she prepared.”