Diseases caused by bacteria Questions in English

(B) Plague is a bacterial disease, not a viral disease.
It is caused by the bacterium $Yersinia$ $pestis$ (formerly known as $Pasteurella$ $pestis$).
It is transmitted to humans through the bite of infected rat fleas $(Xenopsylla$ $cheopis$).

(A) Diphtheria is caused by the toxin released by the bacterium $Corynebacterium$ $diphtheriae$.
Specifically,the bacterial cells themselves do not inherently contain the gene for toxin production.
Instead,a bacteriophage (a virus that infects bacteria) carries the gene for the toxin.
Only those $C.$ $diphtheriae$ cells that are lysogenized by the $\beta$-phage are capable of producing the toxin,which then leads to the symptoms of diphtheria.

(B) Tuberculosis $(TB)$ is an infectious disease primarily affecting the lungs. It is caused by the bacterium $Mycobacterium$ $tuberculosis$. This pathogen spreads through the air when an infected person coughs, sneezes, or talks. The other options are incorrect because $Pseudomonas$ $aeruginosa$ is an opportunistic pathogen, $Streptococcus$ $pneumoniae$ causes pneumonia, and $Escherichia$ $coli$ is typically found in the human intestine.

(A) $Typhoid$ is a bacterial infection caused by the rod-shaped, motile bacterium known as $Salmonella$ $typhi$. This pathogen typically enters the small intestine through contaminated food and water and migrates to other organs through the blood.

(A) The $Widal$ test is a serological test used for the diagnosis of typhoid fever caused by $Salmonella$ $typhi$.
$Mantoux$ test is used for the diagnosis of tuberculosis.
$Schick$ test is used to determine susceptibility to diphtheria.
$Dick$ test is used to determine susceptibility to scarlet fever.
Therefore,the correct option is $A$.

(C) $1$. Typhoid is caused by the bacterium $Salmonella \; typhi$.
$2$. Cholera is caused by the bacterium $Vibrio \; cholerae$.
$3$. Tuberculosis is caused by the bacterium $Mycobacterium \; tuberculosis$.
$4$. Elephantiasis (Filariasis) is caused by filarial worms (helminths) such as $Wuchereria \; bancrofti$ and $Wuchereria \; malayi$.
Therefore,diseases caused by bacterial infection are Typhoid,Cholera,and Tuberculosis.

(C) Intestinal perforation and death may occur in severe cases of $Typhoid$ fever.
$Pneumonia$: Characterized by fever,chills,cough,and headache.
$Plague$: Characterized by high fever,swollen lymph nodes (buboes) in the groin or armpit,and red patches on the skin.
$Pertussis$: Characterized by mild fever,nasal congestion,sneezing,and nasal discharge.

(C) $Yersinia$ $pestis$ is the bacterium that causes the disease plague.
$Trichinella$ $spiralis$ is a parasitic nematode that causes trichinosis.
$Salmonella$ $typhimurium$ is a bacterium that causes gastroenteritis in mammals.
$Xenopsylla$ (rat flea) acts as a vector for transmitting the plague pathogen $Yersinia$ $pestis$.

(A) Typhoid is caused by the bacterium $Salmonella \text{ } typhi$. In some individuals, even after recovery, the bacteria persist in the gall bladder, making them chronic carriers of the disease. Surgical removal of the gall bladder (cholecystectomy) can eliminate this reservoir of infection, thereby curing the carrier state. Thus, both the Assertion and the Reason are correct, and the Reason provides the correct explanation for the Assertion.

(B) Anthrax is a fatal human disease caused by the bacterium $Bacillus$ $anthracis$. In September $2001$,spores of $Bacillus$ $anthracis$ were intentionally spread through the postal system in the United States,marking a significant event involving the use of a biological agent as a weapon.

(N/A) Typhoid fever in humans is caused by the pathogenic bacterium $Salmonella$ $typhi$.
$Salmonella$ $typhi$ generally enters the small intestine of the human body through contaminated food and water.
They migrate through the blood to reach different organs. Lysed bacteria release toxins that have severe effects on the human body.
Sustained high fever ($39$-$40$ $^{\circ}C$),weakness,stomach pain,constipation,headache,and loss of appetite are common symptoms of this disease.
In severe cases,it may lead to intestinal perforation and death.
Typhoid vaccines are available,and the $Widal$ test is used for the diagnosis of typhoid fever.

(B) Mary Mallon,a cook by profession,is a classic case in medicine known as 'Typhoid Mary'.
She was a chronic carrier of the bacterium $Salmonella \ typhi$.
Despite showing no symptoms herself,she continued to spread the infection to many people for several years through the food she prepared.
This led to numerous outbreaks of typhoid fever among those who consumed food prepared by her.

(N/A) Pneumonia in humans is caused by bacteria such as $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$.
These bacteria infect the alveoli (air-filled sacs) of the lungs.
As a result of the infection, the alveoli get filled with fluid, leading to severe respiratory problems.
Due to the fluid accumulation in the alveoli, the diffusion of gases is impaired, and oxygen does not reach the blood capillaries effectively.
The symptoms of pneumonia include fever, chills, cough, and headache.
In severe cases, the lips and fingernails may turn gray to bluish in color.
$A$ healthy person acquires the infection by inhaling droplets/aerosols released by an infected person or by sharing glasses and utensils with an infected person.

(C) The Widal test is a serological test used for the diagnosis of typhoid fever.
It detects the presence of antibodies against the $Salmonella$ $typhi$ bacteria in the patient's blood.
$Pneumonia$ is diagnosed through clinical symptoms and chest $X$-rays.
$Malaria$ is diagnosed by microscopic examination of blood smears.
$AIDS$ is diagnosed using the $ELISA$ test and confirmed by the $Western$ $Blot$ test.

(A) Pneumonia is caused by bacteria such as $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$.
These bacteria are spherical in shape, specifically classified as cocci.
Therefore, the correct shape is spherical.

(D) The pathogen causing typhoid fever is $Salmonella$ $typhi$.
These pathogenic bacteria enter the human body through contaminated food and water.
Upon ingestion,they reach the small intestine,where they migrate into other organs through the blood.
Therefore,the primary site of entry and infection in the digestive tract is the small intestine.

(D) Mary Mallon, popularly known as 'Typhoid Mary', was a cook by profession.
She was a chronic carrier of the bacterium $Salmonella$ $typhi$, which causes typhoid fever.
She continued to spread the disease for several years through the food she prepared.
Therefore, all the given statements are correct.

(A) Typhoid fever is caused by the pathogenic bacterium $Salmonella$ $typhi$.
Common symptoms include sustained high fever ($39^{\circ}C$ to $40^{\circ}C$),weakness,stomach pain,constipation,headache,and loss of appetite.
In severe cases,intestinal perforation and death may occur.
Option $A$ mentions a temperature range of $40^{\circ}C$ to $43^{\circ}C$,which is incorrect as the standard clinical range for typhoid fever is $39^{\circ}C$ to $40^{\circ}C$.

(D) Pneumonia in humans is caused by bacteria such as $Streptococcus$ $pneumoniae$ and $Haemophilus$ $influenzae$.
These bacteria infect 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.
$Salmonella$ $typhi$ is the pathogen responsible for typhoid fever.
Therefore, both $A$ and $B$ are correct.

(C) Pneumonia is caused by bacteria like $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$.
It infects the alveoli (air-filled sacs) of the lungs.
Symptoms include fever, chills, cough, and headache.
In severe cases, the lips and fingernails may turn gray to bluish in color due to lack of oxygen.
Intestinal perforation is a characteristic symptom of $Typhoid$ fever, not pneumonia.
Therefore, option $C$ is incorrect for pneumonia.

(D) $Salmonella$ $typhi$ is the pathogenic bacterium responsible for causing typhoid fever in humans.
This pathogen is primarily transmitted through the fecal-oral route.
It enters the small intestine through contaminated food and water and migrates to other organs through the blood.
Therefore,the correct mode of transmission is contaminated food and water.

(A) Statement-$I$ is correct: Typhoid fever is caused by the pathogenic bacterium $Salmonella$ $typhi$. The Widal test is a diagnostic serological test used to detect the presence of antibodies against $Salmonella$ $typhi$ in the patient's serum,thereby confirming the infection.
Statement-$II$ is correct: In severe cases of typhoid fever,the bacteria can cause sustained high fever,weakness,stomach pain,constipation,headache,and loss of appetite. If the infection is not treated,it can lead to serious complications such as intestinal perforation and death.
Therefore,both statements are correct.

(B) Typhoid fever is caused by the bacterium $Salmonella$ $typhi$.
Common symptoms include high fever,weakness,stomach pain,constipation,headache,and loss of appetite $(Anorexia)$.
Patients often develop a 'rose-coloured' rash on the skin and a white coating on the tongue.
Accumulation of lymph in tissues causing oedema (swelling) is a characteristic symptom of Filariasis (Elephantiasis),caused by $Wuchereria$ $bancrofti$ or $Wuchereria$ $malayi$,not Typhoid.
Therefore,option $B$ is the correct answer.

(B) $Typhoid$ is an acute infection of the intestine caused by the bacterium $Salmonella$ $typhi$.
These are $Gram$ $-ve$ (Gram-negative) bacteria, which means they do not retain the crystal violet stain during the Gram staining process due to their thin peptidoglycan layer.
$Salmonella$ $typhi$ are motile organisms that possess flagella, which contain the "$H$"-antigen.
Their pathogenicity is primarily attributed to the "$O$"-antigen, which is a lipopolysaccharide $(LPS)$ present on their surface coat.

(C) Typhoid fever is caused by the bacterium $Salmonella$ $typhi$.
Its pathogenicity is primarily attributed to the "$O$"-antigen, which is a lipopolysaccharide $(LPS)$ component present on the surface coat of the bacterium.
While typhoid is an infection of the small intestine, it is not typically described as an acute infection of the stomach.
It spreads primarily through contaminated food and water, not through vectors like cockroaches.
Regarding vaccines, the $Ty21a$ vaccine is an oral vaccine, whereas $Typhim$ $Vi$ and $Typherix$ are injectable typhoid polysaccharide vaccines.

(C) The primary lesion known as a $chancre$ is a characteristic symptom of the primary stage of $Syphilis$.
$Syphilis$ is a sexually transmitted infection caused by the bacterium $Treponema \text{ } pallidum$.
$Wuchereria \text{ } bancrofti$ causes $Filariasis$.
$Diplococcus \text{ } pneumonia$ (now known as $Streptococcus \text{ } pneumoniae$) causes $Pneumonia$.
$Salmonella \text{ } typhi$ causes $Typhoid \text{ } fever$.
Therefore, the correct option is $C$.

(D) The oral vaccine $Ty21a$ is a live attenuated vaccine used to provide immunity against $Salmonella$ $typhi$,the bacterium that causes Typhoid fever.
It is administered orally to stimulate the immune system to produce antibodies against the pathogen.
Therefore,it is used for the prevention of Typhoid.

(B) The correct answer is $B$.
$1$. Black rot of crucifers is caused by the bacterium $Xanthomonas campestris$.
$2$. Red rot of sugarcane is caused by the fungus $Colletotrichum falcatum$.
$3$. Brown rust of wheat is caused by the fungus $Puccinia triticina$.
$4$. Late blight of potato is caused by the fungus $Phytophthora infestans$.

(D) Syphilis is a sexually transmitted infection caused by the bacterium $Treponema \text{ } pallidum$.
$A$ characteristic symptom of the primary stage of syphilis is the development of a painless,firm,and ulcerated lesion at the site of infection,which is known as a chancre.

(B) Pneumonia is a respiratory disease caused by bacteria like $Streptococcus$ $pneumoniae$ and $Haemophilus$ $influenzae$.
In severe cases of pneumonia,the alveoli of the lungs get filled with fluid,leading to severe problems in respiration.
As a result of impaired gas exchange,the oxygen levels in the blood decrease,which causes the lips and fingernails of the patient to turn grey to bluish in color.
Option $A$ describes symptoms of malaria.
Option $C$ describes symptoms of typhoid.
Option $D$ describes symptoms of ringworm.
Therefore,the correct option is $B$.

(B) The disease caused by the bacterium $Salmonella$ $typhi$ is Typhoid fever.
To diagnose Typhoid fever,the $Widal$ test is commonly used.
This test detects the presence of antibodies against the $O$ and $H$ antigens of $Salmonella$ $typhi$ in the patient's serum.
Therefore,the correct option is $B$.

(A) The diagnostic test for typhoid fever is the $Widal$ test. It is a serological test that detects the presence of antibodies against the bacterium $Salmonella$ $typhi$ in the patient's blood serum. The test works on the principle of agglutination,where the antibodies in the serum react with the $Salmonella$ antigens.

(C) Pneumonia is caused by bacteria like $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$, while the common cold is caused by rhinoviruses.
Both of these diseases are primarily transmitted through droplets released by an infected person during coughing or sneezing, or by sharing contaminated objects.
Since these pathogens are spread through the air, these are classified as air-borne or air-induced diseases.
Therefore, the correct option is $C$.

(B) The correct answer is $B$.
$Pneumonia$ is a respiratory infection caused by bacteria such as $Streptococcus$ $pneumoniae$ and $Haemophilus$ $influenzae$.
The symptoms of pneumonia include difficulty in breathing,high fever,chills,cough,and headache.
In severe cases,the lips and fingernails may turn gray or bluish in color.

(C) The correct answer is $C$.
$Pneumonia$ is a respiratory infection that affects the alveoli of the lungs.
It is primarily caused by pathogenic bacteria such as $Streptococcus$ $pneumoniae$ and $Haemophilus$ $influenzae$.