Question 1

Which Virus causes Chicken Pox?

Accepted Answer

Answer reason: This same virus can later reactivate to cause shingles (herpes zoster), linking primary varicella and zoster as different clinical expressions of one pathogen. Rubella virus causes German measles, which presents with a different rash pattern and lymphadenopathy and is classically associated with congenital rubella syndrome. Variola virus causes smallpox, a distinct eradicated orthopoxvirus disease with different lesion evolution and severity.

Question 2

The disease 'Tetanus' known as ...?

Accepted Answer

Answer reason: This disinhibition leads to sustained skeletal muscle rigidity and painful spasms, classically involving the masseter muscles. The hallmark clinical presentation is trismus, commonly termed “lockjaw.” Other options describe different conditions (e.g., shingles is varicella-zoster reactivation; whooping cough is pertussis), so they do not match tetanus.

Question 3

Mantoux test is done for?

Accepted Answer

Answer reason: It is used to screen for latent tuberculosis infection and to support TB exposure history in appropriate clinical contexts. The other options are diagnosed with different tests (e.g., serology/NS1 for dengue, blood smear/rapid antigen for malaria, stool culture/antigen testing for cholera) rather than a skin induration response. Interpretation depends on induration size and patient risk factors (immunosuppression, recent exposure, high-risk settings).

Question 4

Most common cause of UTI?

Accepted Answer

Answer reason: Most uncomplicated UTIs are ascending infections caused by enteric gram-negative bacilli originating from the gastrointestinal flora. This organism has adhesins (e.g., P fimbriae) that help it attach to uroepithelium, making it the dominant pathogen in community-acquired cystitis and pyelonephritis. Staphylococcus aureus is an uncommon cause and, when present, more often suggests hematogenous spread or instrumentation rather than typical cystitis. Salmonella and genitourinary tuberculosis are rare causes of UTI compared with common enteric bacteria.

Question 5

Which of the following is a POINT SOURCE epidemic?

Accepted Answer

Answer reason: A single contaminated water supply is a classic common-source exposure that can affect many people at once after a discrete contamination event. Vector-borne diseases like dengue hemorrhagic fever and malaria typically reflect propagated or continuous transmission patterns rather than a single-time common exposure. Tuberculosis generally spreads person-to-person over time, leading to a prolonged, propagated epidemic curve rather than a point-source pattern.

Question 6

Which is a water borne disease?

Accepted Answer

Answer reason: Vibrio cholerae spreads via contaminated water or food and can produce profuse “rice-water” stools with severe dehydration, making it a classic waterborne infection. In contrast, influenza and smallpox spread mainly via respiratory droplets/aerosols and close contact. Malaria is vector-borne, transmitted by Anopheles mosquito bites rather than water ingestion.

Question 7

Which vaccine is given to prevent Tuberculosis?

Accepted Answer

Answer reason: This is the standard vaccine used in many countries, particularly to reduce severe childhood TB forms such as miliary TB and TB meningitis. The other listed vaccines target different pathogens: DPT covers diphtheria, pertussis, and tetanus; polio vaccines prevent poliomyelitis; and measles vaccine prevents measles virus infection. Therefore, the only option aligned with TB-specific immunization is the one selected.

Question 8

What is the cause of Tetanus?

Accepted Answer

Answer reason: The disease results from Clostridium tetani contaminating a wound and releasing tetanospasmin, which blocks inhibitory neurotransmission and leads to muscle rigidity and spasms. This mechanism is characteristic of bacterial toxin–mediated illness rather than viral, fungal, or parasitic pathology. A common distractor is “virus,” but tetanus is not a viral illness and prevention relies on vaccination against the bacterial toxin (tetanus toxoid).

Question 9

Viruses are made up of?

Accepted Answer

Answer reason: The genome is either DNA or RNA (not both), and the capsid is required for protecting the genome and facilitating attachment/entry into host cells. Options stating “DNA only” or “Protein only” omit an essential component found in all viruses. “Cell wall + Cytoplasm” describes cellular organisms (e.g., bacteria) and is incorrect because viruses lack cytoplasm and do not have a true cell wall.

Question 10

Rabies vaccine is given after?

Accepted Answer

Answer reason: Post-exposure prophylaxis with rabies vaccine (and rabies immunoglobulin when indicated) is initiated after a potential rabies exposure from an animal bite or saliva contact with broken skin/mucosa. Snake bites involve venom toxicity rather than rabies virus transmission, so antivenom and supportive care are the priorities. Mosquito bites and bee stings do not transmit rabies and therefore do not warrant rabies vaccination.

Question 11

Candidiasis is a disease of?

Accepted Answer

Answer reason: Because the etiologic agent is a fungus, antifungal therapy (e.g., azoles, nystatin) is the appropriate treatment class, distinguishing it from bacterial, viral, or protozoal infections. Bacteria are prokaryotes and do not cause Candida overgrowth syndromes. Protozoa cause parasitic diseases like giardiasis or malaria, not thrush or vulvovaginal candidiasis.

Question 12

Sleeping sickness is caused by ...?

Accepted Answer

Answer reason: brucei gambiense and T. brucei rhodesiense, transmitted by the tsetse fly. The disease progresses from a hemolymphatic phase to central nervous system involvement, producing sleep disturbances and neurologic signs. Plasmodium instead causes malaria, which is characterized by cyclical fevers and anemia rather than progressive somnolence from CNS invasion. Fungi and viruses can cause encephalitis syndromes, but they are not the classic etiologic agents for “sleeping sickness.”.

Question 13

Which of the following is a curable STD ...?

Accepted Answer

Answer reason: Syphilis is caused by Treponema pallidum and is typically cured with penicillin (stage-appropriate regimen), preventing progression and transmission when treated promptly. Hepatitis B and HIV are viral infections; available treatments control disease activity but do not reliably eliminate the virus from the body. “Genital hepatitis” is not a standard STD diagnosis and does not represent a specific curable condition in this context.

Question 14

Which virus causes Rabies?

Accepted Answer

Answer reason: The pathogen characteristically travels via peripheral nerves to the CNS, leading to fatal encephalitis if post-exposure prophylaxis is not given before symptom onset. Among the choices, only Lyssavirus corresponds to the rabies virus classification; influenza causes respiratory illness, HIV causes immunodeficiency, and HPV causes epithelial infections and cancers. This is a taxonomy/etiology recall item centered on the causative viral genus.

Question 15

Typhoid is caused by —?

Accepted Answer

Answer reason: The condition is therefore classified as a bacterial disease and is treated with appropriate antibiotics along with supportive care and hydration. Viral, fungal, and parasitic organisms do not cause typhoid; confusing it with “typhus” (a rickettsial illness) is a common distractor. Recognizing the causative organism type guides correct prevention measures (sanitation, vaccination) and therapy selection.

Question 16

Sleeping sickness is caused by ...?

Accepted Answer

Answer reason: The vector inoculates Trypanosoma brucei parasites, which then cause systemic illness with later CNS involvement leading to sleep disturbances. Mosquitoes classically transmit malaria and filariasis, not African trypanosomiasis. Sand flies are associated with leishmaniasis, making them a common distractor when testing arthropod vectors.

Question 17

Serology is the study of?

Accepted Answer

Answer reason: These tests are central to diagnosing and monitoring infections (e.g., viral hepatitis, HIV), autoimmune conditions, and immune status after vaccination. The other options refer to different body systems or tissues (bones, nerves, muscles) and are not the specimen type or primary focus of serologic testing. Therefore, the most accurate definition is the study of serum-based immune reactions and components.

Question 18

Zika Virus is spread through?

Accepted Answer

Answer reason: This vector-borne route explains outbreaks in regions where these mosquitoes are prevalent and aligns with standard prevention strategies focused on mosquito control and bite avoidance. Transmission is not via contaminated water or air, which are common distractors for other infectious diseases but do not apply to Zika. Casual touching is not a typical mode of spread, as Zika is not transmitted through routine contact; recognized non-vector routes include sexual and vertical transmission rather than simple touch.

Question 19

When a patient is suffering from typhoid which test is uses for?

Accepted Answer

Answer reason: The Widal test is a serologic agglutination test that detects antibodies against S. typhi O and H antigens and is a traditional test associated with typhoid evaluation. The other options are nonspecific for confirming typhoid: a routine blood test may show leukopenia or anemia but is not diagnostic, and urine testing is not a standard confirmatory test. Although cultures (especially blood culture early in illness) are preferred where available, among the listed choices this is the specific typhoid-related test.

Question 20

Pneumonia is a bacterial disease caused by the type of bacteria called ...?

Accepted Answer

Answer reason: This organism’s coccoid shape (often in pairs) is a classic association tested in basic microbiology. Bacilli can cause pneumonia (e.g., Klebsiella), but they are not the most characteristic or commonly cited “type” for standard community-acquired bacterial pneumonia. Spirilla and Vibrio are generally linked to other clinical syndromes rather than typical pneumonia etiologies.

Question 21

Which ailment is not related to heart?

Accepted Answer

Answer reason: Cardiomyopathy and myocardial rupture are direct pathologies of the heart muscle, and aneurysm is a cardiovascular condition involving abnormal dilation of a vessel (often the aorta) closely tied to cardiac/circulatory disease. Diphtheria is primarily a bacterial upper respiratory tract infection caused by Corynebacterium diphtheriae rather than a primary heart ailment. Although it can cause myocarditis as a complication via toxin effects, it is not fundamentally categorized as a heart disease in this context.

Question 22

Typhoid fever is caused by?

Accepted Answer

Answer reason: The illness features prolonged fever and systemic symptoms due to bacterial invasion and bacteremia. This etiology is treated with appropriate antibiotics and prevented with sanitation measures and vaccination, aligning with a bacterial cause rather than viral, fungal, or protozoal pathogens. Common distractors like viruses typically cause self-limited febrile illnesses without the characteristic enteric bacteremia pattern of typhoid.

Question 23

What is a Bacillus Calmette-Guerin (BCG)?

Accepted Answer

Answer reason: This fits the definition of a live attenuated vaccine because the organism remains viable but has reduced virulence. It is not a toxoid, which is an inactivated bacterial toxin (e.g., tetanus toxoid). It is also not immunoglobulin (passive antibodies) and not a killed vaccine, which would contain inactivated organisms incapable of replication.

Question 24

A health care provider prescribes laboratory studies for an infant of a woman positive for human immunodeficiency virus (HIV) to determine the presence of HIV antigen in the infant. The nurse anticipates that which laboratory study will be prescribed for the infant?

Accepted Answer

Answer reason: An antigen test detects viral proteins and is aligned with the stem’s focus on identifying HIV antigen. Western blot is an antibody confirmatory test and is unreliable for diagnosing infection in young infants due to passive maternal antibodies. CD4+ count helps stage immune suppression but does not diagnose HIV, and a chest x-ray is not a diagnostic test for HIV infection.

Question 25

Worm infestations transmitted through meat are?

Accepted Answer

Answer reason: Tapeworms (e.g., Taenia saginata in beef and Taenia solium in pork) are transmitted via cysticerci in meat. Several roundworms are also meat-associated in common teaching, particularly Trichinella spiralis from undercooked pork/wild game. Hookworm is typically acquired through skin penetration from contaminated soil rather than through meat, making that pairing less appropriate.

Question 26

Which type of pathogen causes the water-borne disease Typhoid fever?

Accepted Answer

Answer reason: The question asks for the pathogen type, so identifying the causative organism’s classification is the key concept. Parasitic and protozoal pathogens can cause water-borne diarrheal illness (e.g., Giardia, Entamoeba), but they do not cause typhoid. Algae are not the etiologic agents of typhoid; at most, some algal toxins cause poisoning syndromes rather than enteric fever.

Question 27

Who discovered Mycobacterium tuberculosis?

Accepted Answer

Answer reason: Koch identified the tubercle bacillus in 1882 and linked it to tuberculosis using systematic experimental criteria (later termed Koch’s postulates). This directly matches the organism named in the stem. A common distractor is Fleming, who is associated with discovery of penicillin rather than the TB bacillus.

Question 28

Which parasite is diagnosed by peripheral blood smear?

Accepted Answer

Answer reason: Malaria parasites demonstrate intraerythrocytic forms on thick and thin smears, allowing both detection and species identification/parasitemia estimation. In contrast, Entamoeba histolytica and Giardia lamblia are primarily diagnosed from stool ova/parasite testing or antigen/PCR assays, and Trichomonas is typically identified from vaginal/urethral wet mount or NAAT. Therefore, the organism most directly diagnosed by peripheral blood smear among the choices is the malaria parasite.

Question 29

Influenza disease is caused by which of the following?

Accepted Answer

Answer reason: Viral pathogens replicate intracellularly and produce systemic symptoms such as fever, myalgias, headache, and fatigue due to host immune response. Bacteria can cause secondary pneumonia after influenza but are not the primary etiologic agent of the disease. Fungi and protozoa do not cause the typical seasonal influenza syndrome in immunocompetent hosts.

Question 30

Which virus causes Measles?

Accepted Answer

Answer reason: Identifying the causative organism is a core microbiology concept used to link a disease to its pathogen and typical transmission/clinical features. Influenza viruses cause seasonal influenza syndrome, not the classic measles prodrome with Koplik spots and morbilliform rash. Adenoviruses more commonly cause respiratory illness, conjunctivitis, and gastroenteritis rather than measles.

Question 31

Which of the following is a vector (carrier) disease?

Accepted Answer

Answer reason: Malaria is caused by Plasmodium species and is transmitted by the bite of the female Anopheles mosquito, making it a classic vector-borne infection. In contrast, mumps and many pneumonias spread primarily through respiratory droplets/airborne routes, not via insect vectors. Cholera is typically transmitted through fecal–oral contamination of water or food rather than by an insect vector.

Question 32

Which of the following is a waterborne disease causing acute gastrointestinal infection?

Accepted Answer

Answer reason: Vibrio cholerae causes profuse watery diarrhea due to enterotoxin-mediated secretion, leading to rapid dehydration and electrolyte loss. Rabies is transmitted via animal bites and causes encephalitis rather than GI illness. Pneumonia and leprosy are primarily respiratory and chronic dermatoneurologic infections, respectively, and are not typical acute waterborne diarrheal diseases.

Question 33

Which of the following viruses is responsible for causing influenza?

Accepted Answer

Answer reason: This family’s respiratory tropism and ability to undergo antigenic drift/shift explains seasonal epidemics and occasional pandemics. Rubella virus causes German measles, varicella virus causes chickenpox, and poliovirus causes poliomyelitis, so they do not match the clinical entity influenza. Therefore the only option aligned with the etiologic agent of influenza is the myxovirus group.

Question 34

The poliovirus enters into the body through ...?

Accepted Answer

Answer reason: After ingestion, it replicates in the oropharynx and gastrointestinal tract before potential spread to the nervous system. Contaminated water supplies and food handled with poor sanitation are classic sources of exposure, especially in areas with inadequate hygiene infrastructure. Animal bites and mosquito transmission are not established routes for poliovirus infection, making those distractors inconsistent with known epidemiology.

Question 35

Typhoid is a caused by-?

Accepted Answer

Answer reason: The illness features prolonged fever and abdominal symptoms due to bacterial invasion and dissemination, not viral replication or fungal overgrowth. Protozoa classically cause diseases like malaria and amoebiasis rather than typhoid. Therefore the etiologic agent class aligns with bacterial pathogens.

Question 36

Tetanus mainly affects which organ/system?

Accepted Answer

Answer reason: The toxin travels retrograde along motor neurons and blocks release of inhibitory neurotransmitters (GABA and glycine) in the spinal cord and brainstem. Loss of inhibition leads to sustained muscle contraction and spasms (e.g., trismus, opisthotonos), reflecting primary neurologic dysfunction. Respiratory compromise can occur secondarily from laryngospasm or chest wall rigidity, but the primary system affected is neural inhibition at synapses.

Question 37

Which age group can be affected by tetanus?

Accepted Answer

Answer reason: Disease risk depends mainly on exposure and immunization status rather than age itself. Neonates, children, adults, and older adults can all develop tetanus if they are unvaccinated, under-immunized, or have waning immunity and sustain a contaminated injury. The age-restricted choices are incorrect because tetanus is not an age-specific infection; prevention requires appropriate vaccination and boosters across the lifespan.

Question 38

What is the shape of Streptococcus pneumoniae?

Accepted Answer

Answer reason: Streptococcus pneumoniae is a gram-positive coccus that classically appears as lancet-shaped diplococci on microscopy. Because its fundamental cell shape is spherical rather than rod, spiral, or filamentous, the coccus option best matches the organism’s morphology. Confusion can arise from the “lancet-shaped” description, but that refers to the paired cocci’s appearance, not a true bacillary form.

Question 39

Which virus causes Chickenpox?

Accepted Answer

Answer reason: After primary infection, the virus becomes latent in dorsal root ganglia and can later reactivate as herpes zoster (shingles). Herpes simplex typically causes oral/genital vesicular lesions rather than generalized varicella, making it a common distractor. Influenza causes an acute respiratory illness without the classic vesicular exanthem, and HPV is associated with warts and cervical/anogenital neoplasia rather than chickenpox.

Question 40

Malaria is caused by?

Accepted Answer

Answer reason: These parasites invade hepatocytes and then red blood cells, producing the characteristic cyclic fevers and hemolysis. Viral, fungal, and bacterial pathogens do not have this erythrocytic life cycle that defines malaria pathogenesis. Therefore the causative organism class is protozoa.

Question 41

Nucleic acid present in corona virus is ...?

Accepted Answer

Answer reason: Therefore the nucleic acid within the virion is RNA rather than DNA. “Oxyribonucleic acid” is not a standard nucleic acid term and does not describe a viral genome. Chromatin refers to DNA packaged with histone proteins in eukaryotic cell nuclei, not a viral genome type.

Question 42

The most common hospital acquired infection is?

Accepted Answer

Answer reason: The urinary bladder is the typical site of these infections because catheter insertion and maintenance can introduce organisms and create a route for ascending infection. This makes urinary tract/bladder infection more common than respiratory or gastrointestinal nosocomial infections in most general inpatient settings. A common distractor is respiratory infection (e.g., ventilator-associated pneumonia), which is significant and high-risk but usually less frequent overall than CAUTI.

Question 43

Rotavirus vaccine prevents?

Accepted Answer

Answer reason: Vaccination induces protective mucosal and systemic immunity that markedly reduces severe gastroenteritis episodes and related dehydration/hospitalization. Because the target pathogen is enteric, prevention is focused on watery stools and vomiting rather than respiratory symptoms or skin manifestations. Fever can occur with many infections but is nonspecific and not the principal disease prevented by this vaccine.

Question 44

Which diagnostic test is most commonly used for typhoid fever?

Accepted Answer

Answer reason: This test is widely used in many settings as a commonly taught/used diagnostic aid for typhoid. Mantoux testing targets tuberculosis, ELISA for dengue targets dengue infection, and rapid strep testing detects Group A Streptococcus pharyngitis—none evaluate Salmonella Typhi. While cultures (especially blood culture early) are more definitive, among the listed choices this is the appropriate and commonly referenced test.

Question 45

A military patient is brought to the ED with a high fever, malaise, body aches, and red bumps all over his face and on his distal extremities. The patient says the rash started in the mouth about two days ago, during a work trip. The patient denies having had chickenpox as a child. The nurse suspects which of the following diagnoses?

Accepted Answer

Answer reason: The rash is typically centrifugal, with prominent lesions on the face and distal extremities, and lesions in a given area tend to be in the same stage of development. Varicella (chickenpox) usually starts on the trunk with lesions in multiple stages simultaneously, and shingles is dermatomal and localized. Rubella produces a milder illness with a maculopapular rash beginning on the face but without the prominent oral enanthem preceding a vesiculopustular eruption.

Question 46

What is the most common cause of urethritis?

Accepted Answer

Answer reason: Among the listed organisms, gonococcal infection is a leading and widely tested cause of urethritis, especially presenting with dysuria and urethral discharge. Escherichia coli more commonly causes cystitis/pyelonephritis rather than primary urethritis, particularly in uncomplicated UTIs. Staphylococcus aureus and Streptococcus pneumoniae are not typical primary causes of urethral infection in standard clinical epidemiology.

Question 47

What is the most common cause of sinusitis?

Accepted Answer

Answer reason: The leading typical bacterial pathogen is Streptococcus pneumoniae, making it the single best answer among the listed organisms. Haemophilus influenzae is also common but is generally the next most frequent cause in many exam frameworks. Staphylococcus aureus is more associated with chronic disease, post-influenza complications, or healthcare-associated settings, and E. coli is not a typical community cause of sinusitis.

Question 48

HIB vaccine is used to prevent?

Accepted Answer

Answer reason: This immunization markedly reduces serious pediatric infections such as meningitis, epiglottitis, pneumonia, and bacteremia caused by type b strains. A common trap is confusing “influenzae” in the organism’s name with the influenza virus; the Hib vaccine does not protect against viral influenza. Hemophilia is a genetic bleeding disorder and Hepatitis A is a viral infection, neither prevented by the Hib vaccine.

Question 49

Which bacterium causes typhoid fever?

Accepted Answer

Answer reason: It invades intestinal lymphoid tissue (Peyer patches) and can lead to bacteremia with prolonged fever and potential intestinal hemorrhage or perforation. Shigella dysenteriae more classically causes bacillary dysentery with bloody diarrhea, while Vibrio cholerae causes profuse watery diarrhea without invasive bacteremia. Campylobacter jejuni is a common cause of inflammatory gastroenteritis and is associated with post-infectious Guillain-Barré syndrome, not typhoid fever.

Question 50

What is the term for the scientific study of fungi?

Accepted Answer

Answer reason: Botany is the study of plants and does not cover fungi as its primary domain. Zoology refers to animal biology. While fungi can be discussed within microbiology broadly, the precise term for the scientific study of fungi is mycology.

Train with a large NCLEX question bank and jump into a full exam-style simulator

Microbiology NCLEX Practice Test

Continue Learning

Which Virus causes Chicken Pox?

The disease 'Tetanus' known as ...?

Mantoux test is done for?

Most common cause of UTI?

Which of the following is a POINT SOURCE epidemic?

Which is a water borne disease?

Which vaccine is given to prevent Tuberculosis?

What is the cause of Tetanus?

Viruses are made up of?

Rabies vaccine is given after?

Candidiasis is a disease of?

Sleeping sickness is caused by ...?

Which of the following is a curable STD ...?

Which virus causes Rabies?

Typhoid is caused by —?

Sleeping sickness is caused by ...?

Serology is the study of?

Zika Virus is spread through?

When a patient is suffering from typhoid which test is uses for?

Pneumonia is a bacterial disease caused by the type of bacteria called ...?

Which ailment is not related to heart?

Typhoid fever is caused by?

What is a Bacillus Calmette-Guerin (BCG)?

A health care provider prescribes laboratory studies for an infant of a woman positive for human immunodeficiency virus (HIV) to determine the presence of HIV antigen in the infant. The nurse anticipates that which laboratory study will be prescribed for the infant?

Worm infestations transmitted through meat are?

Which type of pathogen causes the water-borne disease Typhoid fever?

Who discovered Mycobacterium tuberculosis?

Which parasite is diagnosed by peripheral blood smear?

Influenza disease is caused by which of the following?

Which virus causes Measles?

Which of the following is a vector (carrier) disease?

Which of the following is a waterborne disease causing acute gastrointestinal infection?

Which of the following viruses is responsible for causing influenza?

The poliovirus enters into the body through ...?

Typhoid is a caused by-?

Tetanus mainly affects which organ/system?

Which age group can be affected by tetanus?

What is the shape of Streptococcus pneumoniae?

Which virus causes Chickenpox?

Malaria is caused by?

Nucleic acid present in corona virus is ...?

The most common hospital acquired infection is?

Rotavirus vaccine prevents?

Which diagnostic test is most commonly used for typhoid fever?

What is the most common cause of urethritis?

What is the most common cause of sinusitis?

HIB vaccine is used to prevent?

Which bacterium causes typhoid fever?

What is the term for the scientific study of fungi?

Think you’re ready for the NCLEX?

Leave a Reply Cancel reply