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49 free Infectious Diseases trivia questions with answers — trivia quiz, new questions added Aug 2026.
Smallpox is the only human disease ever eradicated. Tuberculosis still kills more people than any other single pathogen. A cook called Mary spread typhoid without ever feeling ill, and a doctor who told colleagues to wash their hands was driven into an asylum. This infectious disease quiz covers the microbes, the outbreaks and the scientists who fought them: Jenner's cowpox, Pasteur's rabies shot, Koch's postulates, John Snow's pump handle, the 1918 flu, polio, HIV, Ebola, penicillin and the rise of antimicrobial resistance. It works for biology classrooms, nursing students and pub quizzes alike, with every answer sourced and explained.
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Q 01Which is the only human disease ever to have been eradicated?
Smallpox
Smallpox is the only human disease eradicated: the last natural case was a Somali hospital worker, Ali Maow Maalin, in October 1977, and the WHO certified eradication in May 1980.
Q 02Edward Jenner's first vaccination in 1796 used material from which animal disease?
Cowpox
He scraped pus from milkmaid Sarah Nelmes, who had caught it from a cow called Blossom, and inoculated eight-year-old James Phipps. Blossom's hide hangs in a London medical school.
Q 03Which bacterium causes whooping cough?
Bordetella pertussis
Bordetella pertussis causes whooping cough, named for the gasping 'whoop' as a patient inhales after a coughing fit; the P in the DTaP vaccine stands for pertussis.
Q 04Which 9-year-old, mauled by a rabid dog, received Pasteur's rabies vaccine in July 1885?
Joseph Meister
Joseph Meister, bitten by a rabid dog in Alsace, received Pasteur's series of injections from 6 July 1885, survived, and later worked as a caretaker at the Pasteur Institute in Paris.
Q 05Robert Koch's 1876 discovery of the bacterium causing which disease is considered the birth of modern bacteriology?
Anthrax
Anthrax was the disease: in 1876 Koch cultured Bacillus anthracis and traced its spore-forming life cycle; he later identified the TB and cholera bacteria and won the 1905 Nobel Prize for his TB work.
Q 06How many criteria make up Koch's postulates for linking a microbe to a disease?
Four
Four criteria make up Koch's postulates, first set out by Koch and Friedrich Loeffler in 1884 and restated by Koch in 1890; Stanley Falkow's 1988 molecular Koch's postulates later adapted them for genes.
Q 07Before germs were understood, which rival idea blamed disease on 'bad air'?
Miasma
Miasma theory held that rotting matter gave off a poisonous 'bad air'; it dominated European medicine into the 19th century, even though the Roman writer Varro had speculated about invisible disease-causing 'minute creatures' around 36 BC.
Q 08Cholera is an infection of the small intestine by which bacterium?
Vibrio cholerae
Vibrio cholerae produces a toxin that floods the small intestine with fluid, causing watery diarrhoea that can kill an untreated patient within hours; oral rehydration salts cut the death rate below 1%.
Q 09Ignaz Semmelweis cut childbed fever deaths in 1847 by making doctors do what?
Wash hands in chlorinated lime
Wash hands in chlorinated lime was his order at Vienna General Hospital, where the doctors' ward had roughly three times the maternal mortality of the midwives' ward; ridiculed, he died in an asylum in 1865 of a septic wound.
Q 10Which bacterium caused the Black Death?
Yersinia pestis
Yersinia pestis, spread mainly by the bites of infected fleas, caused the Black Death, which killed perhaps a third to a half of Europe's population between 1346 and 1353.
Q 11Which form of plague infects the lungs and spreads between people through the air?
Pneumonic
Pneumonic plague infects the lungs and passes person to person in coughed droplets, unlike bubonic plague, which swells the lymph nodes, and septicemic plague, which infects the blood; both of those are caught from fleas or infected animals.
Q 12The 1918 pandemic was misnamed 'Spanish flu' because of what?
Spain's press was not censored
Spain's press was not censored, since Spain was neutral, so its papers reported the outbreak freely while wartime censors in the combatant nations suppressed the news; the earliest well-documented cases came from Camp Funston, Kansas, in March 1918.
Q 13Roughly how many people were infected in the 1918–1920 flu pandemic?
Q 21Jonas Salk announced a successful vaccine against which disease in April 1955?
Polio
Polio was the target: Salk's killed-virus vaccine was declared safe and effective on 12 April 1955, and he declined to patent it; Albert Sabin's oral vaccine followed in the early 1960s.
Q 22As of the mid-2020s, which two countries remain endemic for wild poliovirus?
Pakistan and Afghanistan
Pakistan and Afghanistan were the only countries where wild poliovirus transmission had never been interrupted as of the mid-2020s; global cases fell from an estimated 350,000 in 1988 to a few dozen a year.
Q 23What was the negative-pressure ventilator used for polio patients commonly called?
The iron lung
500 million
500 million people, about a third of the world's population at the time, are estimated to have been infected by the H1N1 influenza A virus; death estimates range from 17 million to 100 million.
Q 14In flu strain names like H1N1, what do the H and N stand for?
Haemagglutinin and neuraminidase
Haemagglutinin and neuraminidase are the two surface glycoproteins on the envelope of influenza A; 18 H subtypes and 11 N subtypes are known, and the flu virus types are A, B, C and D.
Q 15In 2024, which disease was the leading cause of death from a single infectious agent worldwide?
Tuberculosis
Tuberculosis was the leading infectious killer in 2024, with an estimated 10.7 million cases and 1.23 million deaths; historically called consumption, it has been detected in Egyptian mummies from around 3000 BC.
Q 16Which vaccine, named after two French scientists, protects against TB?
BCG
BCG, Bacillus Calmette-Guérin, is a live weakened strain of Mycobacterium bovis developed by Albert Calmette and Camille Guérin at the Pasteur Institute in Lille and first given to a human in 1921.
Q 17Malaria is caused by single-celled parasites of which genus?
Plasmodium
Plasmodium parasites, chiefly P. falciparum and P. vivax, are injected by female Anopheles mosquitoes and multiply first in the liver, where a single infected cell can release tens of thousands of parasites into the blood.
Q 18About what share of malaria cases and deaths occur in sub-Saharan Africa?
95%
About 95% of malaria cases and deaths occur in sub-Saharan Africa, with children under five accounting for most deaths; first-line treatment is an artemisinin-based combination of two drugs.
Q 19Dengue fever is chiefly spread by mosquitoes of which genus?
Aedes
Aedes aegypti is the main culprit, with the Asian tiger mosquito A. albopictus also involved. More than 5 million infections were reported in 2023.
Q 20Which virus causes chickenpox and, on reactivation, shingles?
Varicella-zoster virus
Varicella-zoster virus causes chickenpox on first infection, then lies dormant in nerve ganglia and can reactivate decades later as the painful rash of shingles.
The iron lung, a sealed tank that breathed for a paralysed patient by cycling the air pressure around the body, was usually needed for one to two weeks, though some patients lived inside one for decades.
Q 24Alexander Fleming discovered penicillin in 1928 as a crude extract of which mould?
Penicillium rubens
Penicillium rubens, long recorded as Penicillium notatum, was the mould Fleming found contaminating a staphylococcus plate at St Mary's Hospital in September 1928 after returning from a Suffolk holiday.
Q 25Who shared the 1945 Nobel Prize in Medicine with Fleming for penicillin?
Florey and Chain
Howard Florey and Ernst Chain's Oxford team isolated the purified compound in 1940, turning a lab curiosity into a drug that could be mass-produced.
Q 26Prontosil, the first systemically active antibacterial drug, was developed in 1932–33 by a team led by whom?
Gerhard Domagk
Gerhard Domagk led the Bayer team that made Prontosil, the first sulfonamide; he used it to save his own daughter from a streptococcal infection and was awarded the 1939 Nobel Prize in Medicine.
Q 27The WHO estimates bacterial antimicrobial resistance directly caused how many deaths in 2019?
1.27 million
1.27 million deaths in 2019 were directly attributable to bacterial antimicrobial resistance in the Lancet GRAM analysis cited by the WHO, which linked a further 4.95 million deaths to resistant infections.
Q 28HIV belongs to which class of virus?
Retrovirus
Retrovirus is HIV's class: it uses reverse transcriptase to copy its RNA genome into DNA that is then inserted into the host cell's chromosomes, which is why the infection cannot be cleared.
Q 29Roughly how many deaths had AIDS caused worldwide by the end of 2023?
42 million
42 million people are estimated to have died from AIDS-related illnesses between the start of the epidemic and the end of 2023; HIV jumped to humans from other primates in Central Africa early in the 20th century.
Q 30Ebola was first reported in which year?
1976
1976 saw the first two recognised outbreaks, in Nzara in Sudan and Yambuku in Zaire, where the virus was named after the nearby Ebola River; the largest epidemic was in West Africa in 2013–16.