Question 1

Rinderpest disease is associated with?

Accepted Answer

Answer reason: Rinderpest is a highly contagious viral disease caused by a morbillivirus that primarily affects cattle and other cloven-hoofed ruminants. It produces fever, oral erosions, diarrhea, and high mortality. The disease does not affect crops, fish, or poultry. Global eradication was declared in 2011, but its association remains with cattle.

Question 2

Genital herpes is caused by?

Accepted Answer

Answer reason: Genital herpes is most commonly caused by herpes simplex virus type 2 (HSV‑2), which establishes latency in the sacral ganglia and recurs with painful genital vesicles. HSV‑1 typically causes orolabial lesions but can also cause genital infections less frequently. HPV causes genital warts and is associated with cervical and other cancers, not herpes. CMV causes mononucleosis-like illness and congenital infections, not genital herpes.

Question 3

Staphylococcus is?

Accepted Answer

Answer reason: Staphylococcus species are Gram-positive cocci that characteristically form grape-like clusters. Their thick peptidoglycan cell wall retains crystal violet dye during Gram staining, giving a purple appearance. They are not bacilli and are not Gram-negative organisms.

Question 4

AIDS can be transmitted by?

Accepted Answer

Answer reason: HIV transmission occurs through specific body fluids containing sufficient viral load, including blood, semen, vaginal fluids, rectal secretions, and breast milk. Saliva and tears contain very low levels of virus and have inhibitory factors, and epidemiologic data show they do not transmit HIV in casual contact. Therefore, among the options listed, semen is the correct route of transmission.

Question 5

AIDS was first reported in year?

Accepted Answer

Answer reason: The first recognized cases of what would later be named AIDS were reported by the CDC in the MMWR on June 5, 1981, describing clusters of Pneumocystis pneumonia in previously healthy men. HIV, the causative virus, was identified a few years later (1983–1984). While retrospective samples suggest earlier infections, the first official report is 1981.

Question 6

Diphtheria is caused by?

Accepted Answer

Answer reason: Diphtheria is an acute infectious disease caused by Corynebacterium diphtheriae, a gram-positive bacillus. The organism produces a potent exotoxin that forms a gray pseudomembrane in the pharynx and can lead to myocarditis and neuropathy. Prevention relies on immunization with diphtheria toxoid.

Question 7

Kala-azar is caused by?

Accepted Answer

Answer reason: Kala-azar, or visceral leishmaniasis, is caused by Leishmania donovani complex, transmitted by female sandflies (Phlebotomus). It typically presents with prolonged fever, weight loss, hepatosplenomegaly, and pancytopenia. Plasmodium causes malaria; Giardia causes giardiasis with malabsorption; and Entamoeba histolytica causes amebic dysentery and liver abscess.

Question 8

Phycology is the study of?

Accepted Answer

Answer reason: Phycology (also called algology) is the branch of biology that studies algae. Mycology refers to the study of fungi, virology to the study of viruses, and the liver is covered in hepatology. Therefore, the correct match for phycology is algae.

Question 9

Leprosy is caused by?

Accepted Answer

Answer reason: Leprosy (Hansen’s disease) is a chronic infection caused by the acid-fast bacilli Mycobacterium leprae or M. lepromatosis. These bacteria infect skin and peripheral nerves, producing hypoesthetic skin lesions and neuropathy. Transmission occurs mainly through prolonged close contact via respiratory droplets. Therefore, the causative agent is bacterial, not viral, protozoal, or fungal.

Question 10

Which of the following is not a communicable disease?

Accepted Answer

Answer reason: Communicable diseases are caused by infectious agents that can be transmitted between people. Hepatitis B, measles, and influenza are all viral infections spread via blood/body fluids or respiratory droplets. Cancer results from uncontrolled cell growth due to genetic and environmental factors and is not transmitted person-to-person, even though some infections can increase cancer risk. Therefore, cancer is not a communicable disease.

Question 11

Rabies is transmitted through?

Accepted Answer

Answer reason: Rabies virus is transmitted when saliva from an infected animal enters broken skin or mucous membranes, most commonly through a bite. There is no foodborne transmission, and mosquitoes do not transmit rabies. Airborne spread does not occur in routine community settings. Therefore, saliva exposure from an infected animal is the route of transmission.

Question 12

Which disease is caused by the protozoan Entamoeba histolytica?

Accepted Answer

Answer reason: Entamoeba histolytica is a pathogenic amoeba that invades the intestinal mucosa, causing amoebiasis (amoebic dysentery) with symptoms such as bloody diarrhea and abdominal pain. Giardiasis is caused by Giardia lamblia, and malaria is due to Plasmodium species, so those options are incorrect. The term dysentery is nonspecific and can be caused by multiple pathogens; the specific disease entity linked to E. histolytica is amoebiasis.

Question 13

Which of the following diseases is transmitted through contaminated water?

Accepted Answer

Answer reason: Typhoid fever is caused by Salmonella Typhi and is transmitted via the fecal-oral route, most commonly through ingestion of food or water contaminated with human feces. Dengue is vector-borne via Aedes mosquitoes. Tuberculosis spreads primarily through airborne droplet nuclei. Rabies is transmitted through the saliva of infected animals, typically via bites.

Question 14

The incubation period of Plasmodium vivax is about?

Accepted Answer

Answer reason: Plasmodium vivax exhibits a tertian periodicity with an erythrocytic cycle of approximately 48 hours, leading to fever spikes every two days. While the true incubation period from infection to symptoms is typically measured in days, the options given in hours indicate the intended concept is fever periodicity. P. malariae shows a 72-hour (quartan) cycle, and 24 or 10 hours are not characteristic of human malarias.

Question 15

Which of the following diseases is caused by a DNA virus?

Accepted Answer

Answer reason: Hepatitis B virus (HBV) is a partially double-stranded DNA virus in the Hepadnaviridae family. In contrast, HIV causing AIDS is an RNA retrovirus, measles virus is an RNA paramyxovirus, and influenza viruses are RNA orthomyxoviruses. Therefore, among the options, only hepatitis B is caused by a DNA virus.

Question 16

Which of the following is a bacterial disease?

Accepted Answer

Answer reason: Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. Dengue and AIDS are viral diseases (dengue virus and HIV, respectively), while malaria is caused by a protozoan parasite (Plasmodium spp.). Therefore, among the options, only tuberculosis is bacterial.

Question 17

Which of the following is caused by a protozoan parasite?

Accepted Answer

Answer reason: Malaria is caused by Plasmodium species, which are protozoan parasites transmitted by Anopheles mosquitoes. Typhoid results from the bacterium Salmonella typhi, filariasis is due to nematode (helminth) parasites such as Wuchereria bancrofti, and influenza is caused by influenza viruses. Therefore, only malaria is protozoan in origin.

Question 18

Pneumonia can be caused by?

Accepted Answer

Answer reason: Streptococcus pneumoniae is the most common bacterial cause of community-acquired pneumonia. Rhinovirus primarily causes the common cold and is not a typical etiologic agent of pneumonia in adults. Mycobacterium leprae causes leprosy, and Plasmodium species cause malaria, neither causing pneumonia. Thus, the best answer is Streptococcus pneumoniae.

Question 19

The disease caused by Wuchereria bancrofti is?

Accepted Answer

Answer reason: Wuchereria bancrofti is a filarial nematode transmitted by mosquitoes that infects and obstructs lymphatic vessels, causing lymphatic filariasis. Chronic lymphatic obstruction leads to severe lymphedema and tissue hypertrophy known as elephantiasis. Leprosy is caused by Mycobacterium leprae, plague by Yersinia pestis, and cholera by Vibrio cholerae, so these options are incorrect.

Question 20

Malaria is caused by?

Accepted Answer

Answer reason: Malaria is caused by protozoan parasites of the genus Plasmodium (e.g., P. falciparum, P. vivax). The female Anopheles mosquito is the vector that transmits the parasite but is not the causative organism itself. Infection of liver cells and red blood cells by Plasmodium leads to cyclic fevers, hemolysis, and anemia.

Question 21

The syphilis is a _____ disease?

Accepted Answer

Answer reason: Syphilis is caused by Treponema pallidum, a motile spirochete bacterium. It is transmitted primarily through sexual contact or vertically during pregnancy, and it responds to penicillin G therapy. Therefore, it is not a fungal, protozoal, or viral disease.

Question 22

Which of these tests is done for typhoid?

Accepted Answer

Answer reason: Typhoid fever is caused by Salmonella Typhi and is traditionally screened with the Widal agglutination test, which detects antibodies to the O and H antigens. Although blood or bone marrow culture is the diagnostic gold standard, Widal remains a common serologic test in many settings. ELISA is not the usual first-line test for typhoid, and a simple urine test is not diagnostic. Therefore, the correct option is the Widal (spelled here as 'Vidal') test.

Question 23

Bacteria infection except?

Accepted Answer

Answer reason: Malaria is caused by Plasmodium species, which are protozoan parasites transmitted by Anopheles mosquitoes, not bacteria. Tetanus is due to Clostridium tetani, tuberculosis to Mycobacterium tuberculosis, and typhoid to Salmonella Typhi—all bacterial pathogens. Therefore, malaria is the exception.

Question 24

Chickenpox is caused by?

Accepted Answer

Answer reason: Chickenpox (varicella) is caused by varicella-zoster virus (human herpesvirus-3). Herpes simplex virus causes oral or genital herpes, not varicella. Vaccinia virus is used in the smallpox vaccine, and rubeola virus causes measles. Therefore, the correct causative agent is varicella-zoster virus.

Question 25

The bacterium used in the production of single-cell protein (SCP) is_____?

Accepted Answer

Answer reason: Single-cell protein refers to microbial biomass used as a protein source; several bacteria are employed due to rapid growth and high protein yield. Bacillus species are among the bacterial genera used for SCP production. Spirulina is typically considered a microalga in SCP contexts, Aspergillus is a filamentous fungus, and Rhizobium is primarily used as a biofertilizer rather than for SCP. Therefore, Bacillus is the best bacterial choice among the options.

Question 26

Typhoid is caused by?

Accepted Answer

Answer reason: Typhoid fever is caused by the bacterium Salmonella enterica serotype Typhi, a Gram‑negative bacillus. It is transmitted via the fecal–oral route through contaminated food or water. Viruses, protozoa, and helminths do not cause typhoid fever, distinguishing it from other infectious diarrheal illnesses.

Question 27

Incubation period of COVID-19 is?

Accepted Answer

Answer reason: SARS-CoV-2 has an incubation period generally ranging from 2 to 14 days, with a median around 4–5 days. This interval reflects the time from exposure to symptom onset and underpinned early public health quarantine guidance. One to two days is too short for most cases, while 30 days and 1 year are implausible for acute respiratory viral infections like COVID-19.

Question 28

Painful genital ulcer is seen in?

Accepted Answer

Answer reason: Herpes simplex virus typically causes painful, shallow genital ulcers that may begin as grouped vesicles and are often tender. In contrast, the primary chancre of syphilis is classically painless. HPV causes genital warts rather than ulcers, and Trichomonas infection produces vaginitis with discharge but no ulceration.

Question 29

The typical membrane in diphtheria is?

Accepted Answer

Answer reason: Corynebacterium diphtheriae produces a thick, adherent pseudomembrane on the tonsils and pharynx composed of necrotic epithelium, fibrin, leukocytes, and bacteria. This membrane classically appears grayish-white and bleeds when attempts are made to remove it. Black suggests eschar/necrosis from other conditions, while yellow or red indicate pus or hyperemia rather than the characteristic diphtheritic membrane.

Question 30

Bacterial flagella help in?

Accepted Answer

Answer reason: Flagella are whip-like protein appendages composed of flagellin that rotate via a basal body powered by the proton motive force. Their primary function is locomotion, enabling bacteria to move toward or away from stimuli (chemotaxis). They do not play roles in reproduction, nutrition, or protection.

Question 31

Hepatitis B surface antigen is abbreviated as?

Accepted Answer

Answer reason: HBsAg stands for hepatitis B surface antigen, the viral protein on the outer envelope of HBV and a marker of active infection or carrier state. HBcAb is the antibody to the core antigen, indicating exposure to HBV. HBeAg is the envelope antigen associated with high infectivity. HAV refers to hepatitis A virus, not a hepatitis B serologic marker.

Question 32

Which one of the following isn’t Gene target for Covid-19 PCR test?

Accepted Answer

Answer reason: SARS‑CoV‑2 RT‑PCR assays commonly target conserved regions such as the E (envelope) gene, RdRp, N, and ORF1ab. The E gene and ORF1ab are widely used for screening and confirmation, and RdRp encodes the viral polymerase. Coronaviruses do not have an “env” gene—this term is used for retroviruses—so “Env gene” is not a valid PCR target for COVID‑19 testing.

Question 33

All of the following diseases are caused by virus except one, that is...?

Accepted Answer

Answer reason: Typhoid is caused by the bacterium Salmonella enterica serotype Typhi, not a virus. Influenza is caused by influenza viruses, and mumps is caused by the mumps (paramyxovirus). Jaundice can result from viral hepatitis, among other etiologies, but the clearly non-viral option here is typhoid.

Question 34

Pasteurization of milk means?

Accepted Answer

Answer reason: Pasteurization is the controlled heat treatment of milk to reduce pathogenic microorganisms, typically the HTST method of 72°C for 15 seconds followed by rapid cooling to about 4°C. This effectively reduces pathogens such as Listeria, Salmonella, and Mycobacterium bovis while preserving quality. Boiling to 100°C is not pasteurization, and fat skimming/homogenization or merely warming and packaging are unrelated processes.

Question 35

Mycology is the study of ______?

Accepted Answer

Answer reason: Mycology is the branch of microbiology that studies fungi, including yeasts, molds, and mushrooms. Fossils are studied in paleontology, protozoa in protozoology, and lizards in herpetology. Therefore, the correct choice is fungi.

Question 36

The shape of Vibrio cholerae bacteria is?

Accepted Answer

Answer reason: Vibrio cholerae is a curved, Gram-negative bacillus characteristically described as comma-shaped. Vibrios are not straight rods, nor true spirals, and they are not cocci. The single curved rod with a polar flagellum gives the classic comma appearance.

Question 37

In malaria infection the rupture of RBCs is associated with release of a toxic substance called?

Accepted Answer

Answer reason: During malaria, Plasmodium digests hemoglobin within RBCs and converts heme to an insoluble crystalline pigment called haemozoin. When infected RBCs rupture at schizogony, haemozoin and other parasite products are released, triggering cytokine release (e.g., TNF-α) that produces fever and systemic symptoms. Therefore, the toxic substance associated with RBC rupture is haemozoin.

Question 38

Which disease is also known as break bone fever?

Accepted Answer

Answer reason: Dengue fever, caused by a mosquito-borne flavivirus, is nicknamed breakbone fever due to the intense myalgia and arthralgia it produces. Patients commonly present with high fever, severe muscle and joint pain, headache with retro-orbital pain, and sometimes rash. Typhoid, hepatitis B, and diphtheria do not classically cause this severe bone-joint pain pattern or carry this moniker.

Question 39

Which parasite is passed in the feces as a noninfective rhabditiform larva?

Accepted Answer

Answer reason: Strongyloides stercoralis typically releases rhabditiform larvae in the stool; these are noninfective and serve as the diagnostic stage. The infective stage is the filariform larva, which can penetrate skin and also cause autoinfection. Hymenolepis nana and Dipylidium caninum are cestodes that pass eggs or proglottids, not rhabditiform larvae. Schistosoma mansoni is a trematode that sheds eggs with lateral spines in feces.

Question 40

Malaria is caused by?

Accepted Answer

Answer reason: Malaria is caused by protozoan parasites of the genus Plasmodium, transmitted by female Anopheles mosquitoes. These parasites infect hepatocytes and then red blood cells, producing cyclic fevers, anemia, and other systemic manifestations. It is not a bacterial or viral disease. Common species include P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi.

Question 41

Which of the following is a Fungal Infection?

Accepted Answer

Answer reason: Tinea corporis (ringworm) is a dermatophyte fungal infection of the skin, typically caused by Trichophyton, Microsporum, or Epidermophyton species. Scabies is an infestation by the mite Sarcoptes scabiei, not a fungus. Eczema is an inflammatory dermatitis, and psoriasis is an autoimmune hyperproliferative skin disorder. Therefore, only tinea corporis represents a fungal infection.

Question 42

Gonorrhea is caused by?

Accepted Answer

Answer reason: Gonorrhea is caused by Neisseria gonorrhoeae, a gram-negative diplococcal bacterium that infects mucous membranes of the genitourinary tract, rectum, and oropharynx. It commonly presents as urethritis or cervicitis and can lead to pelvic inflammatory disease if untreated. Viruses, fungi, and parasites are responsible for other STIs (e.g., HSV, Candida, Trichomonas) but not gonorrhea.

Question 43

Which is the smallest microorganism?

Accepted Answer

Answer reason: Viruses are acellular particles typically measuring about 20–300 nm, far smaller than cellular microbes. Bacteria are usually 0.5–5 µm, while protozoa and fungi are much larger eukaryotes. Therefore, viruses are the smallest among the listed microorganisms.

Question 44

Incubation period of Typhoid fever is?

Accepted Answer

Answer reason: Typhoid fever, caused by Salmonella enterica serovar Typhi, typically has an incubation period of about 7–14 days, influenced by the ingested inoculum and host factors. Shorter periods like hours to a few days are characteristic of preformed toxin or common foodborne illnesses, not typhoid. Two to three months is longer than expected for acute typhoid infection. Therefore, 7–14 days is the best answer.

Question 45

Which of these is not a viral disease?

Accepted Answer

Answer reason: Measles, rabies, and polio are caused by the measles virus, rabies virus, and poliovirus respectively. Tuberculosis is caused by the bacterium Mycobacterium tuberculosis, not a virus. Therefore, among the options, tuberculosis is the one that is not a viral disease.

Question 46

Gold standard test for COVID-19 is?

Accepted Answer

Answer reason: RT-PCR detects SARS-CoV-2 RNA directly from respiratory specimens with high sensitivity and specificity, making it the confirmatory gold standard. CBC findings are nonspecific and cannot diagnose COVID-19. Chest X-ray may show pneumonia but is neither sensitive nor specific for the infection. Urine testing has no role in diagnosing COVID-19.

Question 47

Which of the following Schistosoma species has a large lateral spine?

Accepted Answer

Answer reason: Schistosoma mansoni eggs characteristically have a prominent lateral spine. In contrast, S. haematobium has a terminal spine, while S. japonicum has a small rudimentary lateral knob. S. mekongi eggs resemble S. japonicum with a small lateral projection. Therefore, the species with a large lateral spine is S. mansoni.

Question 48

Which Hepatitis virus is DNA virus?

Accepted Answer

Answer reason: Hepatitis B virus (HBV) is a partially double-stranded DNA virus of the Hepadnaviridae family. In contrast, HAV, HCV, and HEV are RNA viruses. HBV replicates through reverse transcription of an RNA intermediate, a feature unique among hepatitis viruses. This DNA nature underlies its ability to integrate into host hepatocyte DNA and contribute to chronic infection and hepatocarcinogenesis.

Question 49

Malaria fever occurs due to rupture of?

Accepted Answer

Answer reason: The cyclic fever of malaria corresponds to the synchronous rupture of Plasmodium-infected red blood cells during erythrocytic schizogony. This releases merozoites and malarial toxins (e.g., hemozoin, GPI) that trigger proinflammatory cytokines such as TNF-α and IL-1, producing fever and chills. Hepatic schizont rupture is usually clinically silent, and platelets or neutrophils are not the primary cells involved.

Question 50

The infective stage of malaria is?

Accepted Answer

Answer reason: The infective stage of Plasmodium for humans is the sporozoite, which is injected into the bloodstream by the bite of an infected female Anopheles mosquito. Sporozoites travel to the liver and initiate the hepatic stage. Merozoites are produced in the liver and infect red blood cells, while trophozoites and schizonts are developmental stages within human hosts and are not the stage transmitted to humans.

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Rinderpest disease is associated with?

Genital herpes is caused by?

Staphylococcus is?

AIDS can be transmitted by?

AIDS was first reported in year?

Diphtheria is caused by?

Kala-azar is caused by?

Phycology is the study of?

Leprosy is caused by?

Which of the following is not a communicable disease?

Rabies is transmitted through?

Which disease is caused by the protozoan Entamoeba histolytica?

Which of the following diseases is transmitted through contaminated water?

The incubation period of Plasmodium vivax is about?

Which of the following diseases is caused by a DNA virus?

Which of the following is a bacterial disease?

Which of the following is caused by a protozoan parasite?

Pneumonia can be caused by?

The disease caused by Wuchereria bancrofti is?

Malaria is caused by?

The syphilis is a _____ disease?

Which of these tests is done for typhoid?

Bacteria infection except?

Chickenpox is caused by?

The bacterium used in the production of single-cell protein (SCP) is_____?

Typhoid is caused by?

Incubation period of COVID-19 is?

Painful genital ulcer is seen in?

The typical membrane in diphtheria is?

Bacterial flagella help in?

Hepatitis B surface antigen is abbreviated as?

Which one of the following isn’t Gene target for Covid-19 PCR test?

All of the following diseases are caused by virus except one, that is...?

Pasteurization of milk means?

Mycology is the study of ______?

The shape of Vibrio cholerae bacteria is?

In malaria infection the rupture of RBCs is associated with release of a toxic substance called?

Which disease is also known as break bone fever?

Which parasite is passed in the feces as a noninfective rhabditiform larva?

Malaria is caused by?

Which of the following is a Fungal Infection?

Gonorrhea is caused by?

Which is the smallest microorganism?

Incubation period of Typhoid fever is?

Which of these is not a viral disease?

Gold standard test for COVID-19 is?

Which of the following Schistosoma species has a large lateral spine?

Which Hepatitis virus is DNA virus?

Malaria fever occurs due to rupture of?

The infective stage of malaria is?

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