Diseases caused by bacteria Questions in English

(D) Pneumonia is a respiratory disease caused by bacteria such as $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$.
It spreads through the following modes:
$1$. Droplets/aerosols released by an infected person during coughing or sneezing.
$2$. Inhaling these droplets by a healthy person.
$3$. Sharing contaminated objects like glasses and utensils with an infected person.
Therefore, all the given options are correct modes of transmission for pneumonia.

(B) Pneumonia is a respiratory infection caused by bacteria like $Streptococcus \text{ } pneumoniae$ and $Haemophilus \text{ } influenzae$.
Common symptoms of pneumonia include fever, chills, cough, and headache.
In severe cases, the lips and fingernails may turn gray to bluish in color.
Intestinal perforation is a characteristic symptom of typhoid fever, caused by the bacterium $Salmonella \text{ } typhi$, not pneumonia.

(D) Pneumonia is a respiratory disease caused by bacteria.
The primary causative agents of pneumonia in humans are $Streptococcus \text{ pneumoniae}$ and $Haemophilus \text{ influenzae}$.
$Microsporum$ is a fungus responsible for ringworm.
$P. falciparum$ is a protozoan responsible for malaria.
$Wuchereria$ is a filarial worm responsible for filariasis.
Therefore, the correct option is $D$.

(B) The disease known as $Black \ rot$ in cabbage is caused by the bacterium $Xanthomonas \ campestris$.
Brown rust is a fungal disease affecting various crops,and Red rot is a well-known fungal disease of sugarcane caused by $Colletotrichum \ falcatum$.
Therefore,the correct option is $B$.

(B) Diphtheria is an acute infectious disease caused by the bacterium $Corynebacterium$ $diphtheriae$.
It primarily affects the mucous membranes of the throat and nose.
It is a bacterial infection,not caused by fungi,nematodes,or protozoans.

(D) Cholera is an infectious disease caused by the bacterium $Vibrio \text{ } cholerae$.
It is primarily transmitted through the ingestion of contaminated water or food.
Therefore, water pollution is the primary environmental factor that leads to the spread of cholera.
Drinking pure water and eating hygienic food are preventive measures, not causes.

(A) Citrus canker is a plant disease that affects citrus species.
It is caused by the bacterium $Xanthomonas \text{ } citri$.
This bacterium infects the leaves, stems, and fruits of citrus trees, leading to the formation of characteristic lesions or cankers.
Therefore, it is classified as a bacterial disease.

(B) Citrus canker is a plant disease that affects citrus species.
It is caused by the bacterium $Xanthomonas$ $citri$ $subsp.$ $citri$.
This disease is characterized by lesions on the leaves,stems,and fruit of citrus trees,which can lead to premature fruit drop and reduced fruit quality.
Therefore,it is classified as a bacterial disease.

(A) Bacterial leaf blight of rice is a serious disease caused by the bacterium $Xanthomonas$ $oryzae$ $pv.$ $oryzae$. This pathogen infects the leaves of the rice plant,leading to yellowing and drying of the leaf blades,which significantly reduces crop yield. Therefore,the correct option is $A$.

(A) Diphtheria is a serious bacterial infection caused by the bacterium $Corynebacterium$ $\text{diphtheriae}$.
It is primarily caused by the secretion of a potent exotoxin by the living bacteria that colonize the host's throat and upper respiratory tract.
This toxin inhibits protein synthesis in the host cells, leading to cell death and the formation of a characteristic greyish pseudomembrane in the throat.

(D) $Clostridium$ $botulinum$ produces a potent neurotoxin called botulinum toxin.
This toxin specifically targets the $neuromuscular$ $junction$.
It prevents the release of the neurotransmitter $acetylcholine$ from the nerve endings.
As a result, the muscle fibers cannot receive the signal to contract, leading to flaccid paralysis.

(B) Typhoid fever is a bacterial infection caused by the bacterium $Salmonella$ $typhi$.
It is primarily transmitted through the ingestion of contaminated food or water.
Symptoms include high fever, weakness, stomach pain, headache, and loss of appetite.
Therefore, the correct option is $B$.

(B) Koch's postulates are a set of criteria designed to establish a causative relationship between a microbe and a disease.
However, they cannot be applied to all pathogens.
Leprosy (caused by $Mycobacterium leprae$) is an example where Koch's postulates are not applicable because the causative agent cannot be grown in a cell-free culture medium (it is an obligate intracellular parasite).
Therefore, the correct answer is $B$.

(A) $Salmonella \text{ } typhi$ is a pathogenic bacterium that causes typhoid fever in human beings.
It is transmitted through the ingestion of contaminated food and water.
Symptoms include high fever, weakness, stomach pain, constipation, headache, and loss of appetite.

(D) The Widal test is a serological test used for the diagnosis of typhoid fever.
It detects the presence of antibodies against the antigens of the bacterium $Salmonella$ $typhi$ in the patient's serum.
$Salmonella$ $typhi$ is the causative agent of typhoid fever in humans.

(C) The correct answer is $C$.
$1$. Cholera is caused by the bacterium $Vibrio cholerae$.
$2$. Tetanus is caused by the bacterium $Clostridium tetani$.
$3$. Mumps, Herpes, Influenza, and Smallpox are all caused by viruses.
Therefore, the pair consisting of Cholera and Tetanus is caused by bacteria.

(D) Typhoid fever is a bacterial infection caused by the pathogen $Salmonella \ typhi$.
This bacterium typically enters the small intestine through contaminated food and water and migrates to other organs through the blood.
The standard diagnostic test used to confirm the presence of $Salmonella \ typhi$ antibodies in the patient's serum is the $Widal \ test$.
Therefore,the correct pair is $Salmonella \ typhi$ and $Widal \ test$.

(B) $Escherichia$ $coli$,$Shigella$ $sp.$,and $Salmonella$ $sp.$ are pathogenic bacteria that cause diarrhoeal diseases,typically through the ingestion of contaminated food or water.
Dehydration is a major clinical consequence of all diarrhoeal diseases due to the loss of water and essential salts from the body.
Therefore,both statements are correct,but the Reason does not explain why these specific bacteria cause the disease; it only describes a common clinical management aspect of the condition. Thus,the Reason is not the correct explanation of the Assertion.

(B) Citrus canker is a plant disease caused by the bacterium $Xanthomonas$ $citri$.
$Wilt$ $disease$ is typically caused by $Fusarium$ $oxysporum$.
$Red$ $rot$ $of$ $sugarcane$ is caused by the fungus $Colletotrichum$ $falcatum$.
$Powdery$ $mildew$ is caused by various fungi such as $Erysiphe$ or $Oidium$.

(D) Tuberculosis is caused by $Mycobacterium$ $tuberculosis$, and leprosy is caused by $Mycobacterium$ $leprae$. Both are bacterial infections. Rifampicin is a broad-spectrum antibiotic that is highly effective against both $Mycobacterium$ $tuberculosis$ and $Mycobacterium$ $leprae$, making it a standard drug used in the multi-drug therapy for both diseases.

(A) The correct matches are as follows:
$A$. Treponema pallidum causes Syphilis $(A-III)$.
$B$. Yersinia pestis causes Plague $(B-I)$.
$C$. Bacillus anthracis causes Anthrax $(C-II)$.
$D$. Vibrio (specifically Vibrio cholerae) causes Cholera $(D-IV)$.
Therefore, the correct sequence is $A-III, B-I, C-II, D-IV$.

(B) $Yersinia pestis$ (formerly known as $Pasteurella pestis$) is the bacterium that causes Bubonic Plague.
This pathogen is primarily transmitted to humans through the bite of infected rat fleas,specifically the species $Xenopsylla cheopis$.
$Cimex$ refers to bedbugs,$Pediculus$ refers to lice,and $Aedes$ is a genus of mosquitoes known for transmitting diseases like Dengue and Chikungunya.
Therefore,the correct vector for the transmission of $Yersinia pestis$ is $Xenopsylla$.

(D) Tetanus is caused by the bacterium $Clostridium$ $tetani$.
$Pasteurella$ $pestis$ (also known as $Yersinia$ $pestis$) is the causative agent of plague,not tetanus.
Therefore,the pair $Tetanus - Pasteurella$ $pestis$ is incorrectly matched.

(B) Diarrhoeal diseases involve the frequent and excessive discharge of watery stools from the bowel.
These diseases are primarily caused by the ingestion of harmful pathogens through contaminated food and water.
$Escherichia$ $coli$,$Shigella$ $sp.$,and $Salmonella$ $sp.$ are well-known bacterial pathogens that cause diarrhoea.
Diarrhoea caused by these organisms involves two main mechanisms: first,the pathogens colonize the intestine,causing inflammation (enteritis); second,they disrupt the balance of intestinal fluid absorption and secretion,significantly increasing fluid loss,which manifests as frequent,watery stools.
Dehydration is a common and dangerous consequence of all types of diarrhoeal diseases.
Therefore,maintaining an adequate supply of fluids and electrolytes is essential for the management and treatment of these conditions.
Since both statements are factually correct but the reason describes the management of the disease rather than explaining why these specific bacteria cause the disease,the correct option is $B$.

(N/A) $Salmonella \ typhi$ is a pathogenic bacterium which causes $Typhoid$ fever in humans. These pathogens generally enter the small intestine through contaminated food and water and migrate to other organs through the blood.
Common symptoms of this disease include sustained high fever ($39^o C$ to $40^o C$),weakness,stomach pain,constipation,headache,and loss of appetite. In severe cases,intestinal perforation and death may occur. The diagnosis of this disease is confirmed by the $Widal \ Test$.
$A$ classic case in medicine is that of $Mary \ Mallon$,nicknamed $Typhoid \ Mary$. She was a cook by profession and remained a carrier of this disease for several years through the food she prepared.

(N/A) Bacteria such as $Streptococcus$ $pneumoniae$ and $Haemophilus$ $influenzae$ are responsible for the disease $Pneumonia$ in humans.
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.
The symptoms of this disease include fever,chills,cough,and headache. In severe cases,the lips and fingernails may turn gray to bluish in color.
In healthy individuals,the infection spreads by inhaling the droplets or aerosols released by an infected person during coughing or sneezing,or by sharing glasses and utensils with an infected person.

(C) The Widal test is a diagnostic serological test used for the detection of typhoid fever.
Typhoid fever is caused by the bacterium $Salmonella \ typhi$.
This test detects the presence of antibodies against the $O$ (somatic) and $H$ (flagellar) antigens of $Salmonella \ typhi$ in the patient's serum.
Therefore,a positive Widal test indicates an infection by $Salmonella \ typhi$.

(C) Typhoid fever is caused by the pathogenic bacterium $Salmonella$ $typhi$.
Common symptoms of typhoid include high fever ($39^{\circ}C$ to $40^{\circ}C$),weakness,stomach pain,constipation,headache,and loss of appetite.
Severe cases may lead to intestinal perforation and death.
Watery diarrhea is typically associated with diseases like cholera or rotavirus infections,not typhoid,which is more commonly associated with constipation.

(A) The term 'Typhoid Mary' refers to Mary Mallon, a cook by profession, who was a chronic carrier of $Salmonella \text{ } typhi$. She continued to spread the typhoid fever through the food she prepared for years without showing symptoms herself. This case is a classic example in epidemiology of a healthy carrier transmitting a disease.

(B) The pathogen $Haemophilus$ $influenzae$ is a bacterium that is responsible for the disease pneumonia in humans,which specifically infects the alveoli (air-filled sacs) of the lungs.
$Rhinovirus$ primarily causes the common cold,which affects the nose and respiratory passage but not the lungs.
$Corynebacterium$ $diphtheriae$ causes diphtheria,which primarily affects the throat and upper respiratory tract.
Therefore,among the given options,$Haemophilus$ $influenzae$ is the pathogen that infects the lungs.

(D) In severe cases of pneumonia,the alveoli get filled with fluid leading to severe problems in respiration.
As a result,the exchange of gases is impaired,causing the lips and fingernails to turn from grey to a bluish color.
Pneumonia is caused by bacteria such as $Streptococcus$ $pneumoniae$ and $Haemophilus$ $influenzae$.
Therefore,both the disease name $(A)$ and the causative agent $(B)$ are correct in the context of the symptoms described.

(C) Typhoid fever is caused by the bacterium $Salmonella \text{ } typhi$.
It is a water-borne disease that spreads primarily through the ingestion of contaminated food or water.
Pathogens enter the small intestine through these sources and migrate to other organs through the blood.
Therefore, the correct mode of transmission is contaminated food or water.

(D) The correct answer is $Clostridium \ botulinum$.
$Clostridium \ botulinum$ produces a potent neurotoxin known as botulinum toxin.
This toxin blocks the release of the neurotransmitter acetylcholine at the neuromuscular junction,leading to muscle paralysis and a condition known as botulism.
While other bacteria listed also cause diseases,$Clostridium \ botulinum$ is specifically characterized by the production of a highly lethal exotoxin that causes severe toxic effects in the body.

(D) The diseases Mumps, Measles, and Chickenpox are caused by viruses.
$1$. Mumps is caused by the Mumps virus.
$2$. Measles is caused by the Measles virus (Rubeola).
$3$. Chickenpox is caused by the Varicella-zoster virus.
$4$. Tetanus is a bacterial disease caused by the bacterium $Clostridium \text{ } tetani$.
Therefore, Tetanus is not a viral disease.

(D) Diseases spread through the air are known as airborne diseases.
$1$. Pneumonia is caused by $Streptococcus pneumoniae$ and $Haemophilus influenzae$, which spread through droplets released by an infected person.
$2$. Common cold is caused by rhinoviruses, which are transmitted through droplets resulting from cough or sneezes.
$3$. Tuberculosis $(T.B.)$ is caused by $Mycobacterium tuberculosis$, which spreads through air droplets.
Therefore, the correct group is Pneumonia, Common cold, and Tuberculosis $(T.B.)$.

(B) $Black\, Death$ refers to the bubonic plague pandemic that occurred in the $14^{th}$ century.
It is caused by the bacterium $Yersinia\, pestis$.
Therefore,the pathogen responsible for this disease is a bacterium.

(C) Penicillin is an antibiotic that functions by interfering with the synthesis of the bacterial cell wall.
It specifically targets the peptidoglycan layer,which is essential for the structural integrity of the bacterial cell.
By inhibiting the enzymes (transpeptidases) responsible for cross-linking the peptidoglycan chains,penicillin weakens the cell wall,leading to cell lysis and death of the bacteria.
Streptomycin and Azithromycin,on the other hand,primarily inhibit bacterial protein synthesis.

(C) The correct answer is $C$. Pertussis,also known as whooping cough,is caused by the bacterium $Bordetella \ pertussis$,not a virus. Therefore,the pairing of Pertussis with a virus is incorrect. Polio is caused by the Poliovirus,Dengue is caused by the Flavivirus (an arbovirus),and Rabies is caused by the Rabies virus (Lyssavirus).

(C) The $TAB$ vaccine is a combined vaccine used to provide immunity against typhoid fever,paratyphoid $A$,and paratyphoid $B$.
$BCG$ is used for tuberculosis.
$DPT$ is used for diphtheria,pertussis,and tetanus.
Therefore,the correct option is $C$.

(A) The $Mantoux$ test,also known as the $PPD$ (Purified Protein Derivative) test,is a standard screening tool used to diagnose tuberculosis $(TB)$.
In this test,a small amount of $PPD$ tuberculin is injected just under the skin of the forearm.
$A$ positive result indicates that the person has been exposed to the bacteria $Mycobacterium$ $tuberculosis$ at some point in their life.
The $Widal$ test is used for typhoid fever,the $Schick$ test for diphtheria,and $ELISA$ is commonly used for $HIV$ or other immunological assays.

(C) Penicillin and streptomycin are broad-spectrum antibiotics used to treat bacterial infections.
$T.B.$ (Tuberculosis) is caused by the bacterium $Mycobacterium$ $tuberculosis$.
Streptomycin is specifically known for its effectiveness against $Mycobacterium$ $tuberculosis$.
Therefore, these antibiotics are commonly used in the treatment of $T.B.$

(B) Black rot of crucifers is a serious plant disease caused by the bacterium $Xanthomonas$ $campestris$ $pv.$ $campestris$.
This pathogen infects members of the $Brassicaceae$ family,such as cabbage,cauliflower,and broccoli.
It enters the plant through hydathodes or wounds and spreads through the vascular system,causing yellowing and necrosis of the leaves.

(C) The black rot of mustard is caused by the bacterium $Xanthomonas \ campestris$.
In this disease,the leaves turn yellow and develop $V$-shaped necrotic lesions.
The causative organism can remain present in the plant residues for around $1-2$ years.

(D) Cholera is a bacterial disease caused by the pathogen $Vibrio$ $cholerae$.
Leprosy is also a bacterial disease caused by $Mycobacterium$ $leprae$.
Since both are caused by bacteria, they are not viral diseases.

(C) Anthrax is a serious infectious disease caused by the bacterium $Bacillus$ $anthracis$.
It primarily affects domestic and wild animals such as cattle,buffaloes,horses,sheep,and goats.
Anthrax is a zoonotic disease,meaning it can be transmitted from animals to humans through contact with infected animals or their products.

(A) Anthrax is a serious infectious disease caused by the bacterium $Bacillus$ $anthracis$.
When an animal is infected with anthrax,the bacteria multiply rapidly in the blood,leading to septicemia.
These bacteria consume the oxygen present in the blood,causing severe hypoxia (lack of oxygen) in the animal's tissues and organs.
This rapid depletion of oxygen leads to the death of the animal.
Therefore,both the Assertion and the Reason are correct,and the Reason provides the correct explanation for the Assertion.

(C) The correct answer is $C$. $Mycoplasma$ (specifically $Mycoplasma$ $hominis$ and $Ureaplasma$ $urealyticum$) are known to be associated with reproductive tract infections that can lead to complications such as spontaneous abortion,preterm labor,and infertility in humans. While certain bacteria and fungi can cause infections,$Mycoplasma$ is specifically noted in clinical literature for its association with adverse pregnancy outcomes including abortion.

(B) The $1^{\circ}$ (primary) stage is characterized by the appearance of a painless open sore called a chancre at the site of infection.
The $2^{\circ}$ (secondary) stage is characterized by a skin rash,fever,and aches in the joints and muscles.
The $3^{\circ}$ (tertiary) stage involves severe organ degeneration and damage to internal systems.
Neurosyphilis occurs when the bacteria damage the organs of the nervous system.

(C) Tetanus is also known as 'lock jaw' disease.
It is caused by the bacterium $Clostridium \ tetani$.
In this condition,the jaw muscles become stiff and locked,making it difficult to open the mouth.

(D) healthy person acquires the pneumonia infection by inhaling the droplets or aerosols released by an infected person,or by sharing contaminated items like glasses and utensils with an infected person.