Suck It: The Ins and Outs of Mouth Pipetting


If you ever find yourself working in an infectious disease laboratory, whether it’s of the diagnostic or research variety, the overarching goal is not to put any microbes in your eye, an open wound or your mouth. Easy enough, right? Wear gloves, maybe goggles, work in fume hoods and don’t mouth pipette. When working with pathogenic bacteria and viruses, priority number one is Do Not Self-Inoculate.

This is obvious for anyone who has worked in a shiny biology or chemistry lab or seen an episode of CSI: Crime Scene Investigation (we’re all friends here, just admit it), but one of the most commonly used pieces of equipment in labs prior to the 1970s was the leading cause of laboratory-derived infections: the honorable pipette. How could that be possible, you ask? By using one’s oral cavity with the pipette to measure and transfer liquids.

Today our manual pipettes are rather sophisticated, plastic-y devices perfectly calibrated for moving precisely exact milliliters, microliters and picoliters of valuable solution from one vessel to another, whether it’s of a urine sample, some spare radioactive material you have lying about or toxic solvents. But before the development of cheap mechanical pipettes in the ’70s, using your mouth to pipette solutions was more than a common sight, it was a way of the lab.

Former Centers for Disease Control (CDC) parasitologist, Dr. Mae Melvin (Lt), examines a collection of test tubes while her laboratory assistant mouth pipettes a culture to be added to these test tubes. Source: David Senser/CDC.

Don’t worry, reader, I heard you tentatively whisper, “just what exactly is mouth pipetting, dare I ask?”

Like so: insert an open-ended glass capillary tube into your mouth. Place the opposite, tapered end of the tube into a solution of your choice. Microbial stews, blood, cell culture, it is totally your call. With a method that carefully mimics the sucking of a straw, draw a solution upwards through your man-made pipette to your desired volume using the tension created by the reduced air pressure – yes, suction! Maintain the tension with your mouth. Do not suck too hard and inadvertently slurp the solution into your mouth. Careful now. Gently move the pipette end from one vessel and release your precious cargo into yet another vessel.

That is mouth pipetting.

A wonderful demonstration of mouth pipetting by Dr. Armand Frappier, a microbiologist and expert on tuberculosis. Look closely: you can see him draw a dark liquid slowly towards his mouth. What could it be? Soda, a culture of TB, serum for cell cultures? You can watch the entire video clip that this GIF is based upon here. Source: Musée Armand Frapper.

The sparsity of history on pipetting techniques (itself a shocking shortcoming, I’m sure you’ll agree), forbids us from generalizing the prevalence of this phenomena. But we do know that it was the source of a ridiculous number of accidents, whether swallowing a corrosive or toxic substance or an infection with one’s research material  (1). A survey of 57 labs in 1915 found that 47 infections  were associated with workplace practices and more than 40% of those were attributed to the practice of mouth pipetting. A longitudinal study of 921 workplace laboratory infections from 1893 and 1950 found that 17% were due to “oral aspiration through pipettes or to splashes of culture fluids into the mouth (2).”

Infection through the use of one’s oral cavity was such an occupational hazard that it warranted an article, “The Hazards of Mouth Pipetting,” from two gentleman working for the U.S. Army Biological Laboratories. In 1966 they wrote,

although the use of pipettes in the early chemistry laboratories undoubtedly led to accidental aspiration of undesirable toxic and poisonous substances, the first recorded laboratory infection due to mouth pipetting occurred in 1893 … [with] the case of a physician who accidentally sucked a culture of typhoid bacilli into his mouth …

compared with the equipment and procedures required to avoid other types of microbiological laboratory hazards, the method of avoiding pipetting hazards is so elementary, so simple, and so well-recognized that it seems redundant to mention it [emphasis added by author]. However, continued accidents and infections in laboratories illustrate, even today, that there is a lack of acceptance of the simple precautionary measured needed (2).

By the 1970s, mouth pipetting had fallen out of favor as swanky, mechanically adjustable and cheap pipettes flooded the market (3). They were not only infinitely safer but also far more accurate. Instead of drawing a semi-approximate volume of solution with the imperfect measuring device that is your mouth, standardized and calibrated pipettes were available that could zip up a solution to one’s desired volume. More precision. Better experimental results. Less contamination. More ergonomic. Fewer infections. Nowadays, mouth pipetting is explicitly banned from laboratories.

A woman mouth pipetting to select specimens of ectoparasites. Source: National Library of Medicine

And, indeed, you might think that this old school technique is thankfully old news and good for a giggle but mouth pipetting is still practiced in some countries. A study looking at the lab practices and biosafety measures of Pakistani lab technicians found that mouth pipetting was reported by 28.3% technicians (4). This paper was published just last year, in August of 2012. Another study in 2008 found that Nigerian technicians working in clinical laboratories were not only improperly vaccinated against many of the preventable diseases that they were testing for (!) as well as eating and drinking in the lab but 1 in 10 also reported mouth pipetting (5).

Lest you think this is just happening in developing countries, be rest assured that American teenagers and young adults will always find a creative way to  jeopardize their health. In 1998, a 19-year-old nursing student in Pennsylvania was  hospitalized for several days following infection with a unique strain of Salmonella paratyphi she was working with in a lab; the case report strongly suggests that mouth pipetting was the culprit behind this particular microbial misadventure (6).

Another article from 1995 assessing lab accidents found that 13% of laboratory-acquired infections were a result of mouth pipetting. That’s 92 accidents attributed to someone in a lab deliberately putting a pipette or capillary tube into their mouth and sucking up some solution laden with microbes (7). Clearly, we still have a way to go in dissuading people to stop using pipettes as straws.

A techician mouth-pipetitng environmental water samples in Malta. Image: E Mandelmann. Source: History of Medicine

A technician mouth pipetting environmental water samples in Malta. Image: E Mandelmann. Source: History of Medicine

Mechanical manual pipettes have been a godsend to technology and the sciences, saving researchers time and resources in measuring and transferring liquids. Pipettes now serve as an icon of the scientific pursuit of knowledge – we’re all familiar with the close up of the gloved hand and pipette tip hovering over some glowing liquid. It’s banal, efficient and ubiquitous. It’s the dogged, unsung hero of the lab but there were several decades when our method of pipetting was also a microbial misadventure in the waiting.


“There are reports of laboratory infections by means of the pipette with quite a variety of microorganisms. In the intestinal group: typhoid, Shigella, salmonella, cholera; among others, anthrax, brucella, diphtheria, hemophilus iniluenzae, leptothrix, meningococcus, Streptococcus, syphilis, tularemia; among viruses, mumps, Coxsackie virus, viral hepatitis, Venezuelan equine encephalitis, chikungunya, and scrub typhus.” Download this neat article on the history and epidemiology of lab-acquired infections here.

Want to see more pictures of mouth pipetting? Of course you do! I’ve been collecting them on the Body Horrors tumblr here, here, here, here and here. Here’s a sign. And here’s a riff on a meme.


1) AG Wedum. (1997) History and epidemiology of laboratory-acquired infections. J Am Bio Safety Assc. 2(1): 12-29

2) Phillips GB &Bailey SP (1966) Hazards of mouth pipetting. Am J Med Technol. 32(2): 127-9

3) JA Martin (April 13, 2001) The Art of the Pipette BiomedNet Magazine100

4) S Nasim et al (2012) Biosafety perspective of clinical laboratory workers: a profile of Pakistan. J Infect Dev Ctries. 6(8): 611-9

5) FO Omokhodion (1998) Health and safety in clinical laboratory practice in Ibadan, Nigeria. Afr J Med Med Sci. 27(3-4): 201-4

6)B Boyer et al (1998) The microbiology “unknown” misadventure. Am J Infect Control. 26(3):355-8

7) DL Sewel (1995) Laboratory-Associated Infections and Biosafety. Clin Micro Rev. 8(3): 389-405
HILL, N. (1999). Laboratory-acquired Infections: History, Incidence, Causes and Preventions, 4th edition. Eds. C. H. Collins and D. A. Kennedy. Butterworth Heinemann, Oxford 1999. Pp. 324. ISBN 0 7506 4023 5. Epidemiology and Infection, 123 (1), 181-181 DOI: 10.1017/S0950268899002514

May the Vaccines Be With You!


The poster for the clever Star Wars Public Service Announcement featuring C-3PO and R2-D2 from the CDC and the Department of Health, Education, and Welfare encouraging parents to vaccinate their children against preventable infections. Click for source.

What is the best way to persuade parents to get their kids vaccinated against preventable diseases? Tug sentimentally at the heartstrings? Appeal to common sense and logic? Shame and blame?

Or how about going the pop culture route and using characters from one of the most popular movies in history as the CDC and the Department of Health, Education, & Welfare did in April 1978?

The poster on the right and the short commercial below feature the characters C-3PO and R2-D2 speaking directly to the “parents of Earth” on the necessity of vaccinating their children fully against polio, measles and whooping cough and the dangers of not doing so. As C-3PO admonishes a coughing R2-DC, “Droids don’t get diseases like whooping cough, or measles, or polio. But children do. All you need is a little rewiring but children need to be fully immunized but, alas, so many are not.”

I think it’s a particularly inspired moment in public health propaganda. If you’re going to convince wary parents to get their children vaccinated, why not use the Force?

– Rebecca Kreston


See more public health posters from the National Library of Medicine’s exhibition, “To Your Health: An Exhibition of Posters for Contemporary Public Health Issues.”

Washington state is the midst of a whooping cough epidemic – there were 4,815 cases of the disease last year – and certain types of vaccines may be to blame for a drop in efficiency and protection over time. Maryn McKenna goes into greater detail here.

The White House just quashed a petition for the country to “secure resources and funding, and begin construction of a Death Star by 2016.” Paul Shawcross, the Chief of the Science and Space Branch at the White House Office of Management and Budget, has a very inspiring and feel-good letter about why the Death Star will not be built but that the USA is on the right track for space exploration irregardless.


Wookieepdia: The Star Wars Wiki. (Unknown date of publishing) “Star Wars Immunization PSA.” Accessed January 15, 2013 here.

Boyle, Eric (September 23, 2003) “Infectious Disease: Immunization.” From the  Visual Culture & Public Health Posters Exhibit. National Institutes of Health [Online.] Accessed January 15, 2013 here.

Nobel Prizes, Tropical Medicine & One Nazi Sympathizer


Nobel Prizes! We all want one, don’t we? While fantasizing about heavy gold medallions and the Swedish Nobel Assembly, I wondered how many of the Nobel Laureate prizes in Physiology and/or Medicine have gone towards scientists studying infectious diseases, immunology and the tropical medicine field. Snooze button alert, am I right? This is the product of a one-track mind so you have my apologies. But! If it’s any consolation, there’s a story hidden in this article of a Nobel Laureate Nazi sympathizer that infected mental patients with malaria to cure them of their psychoses. Science!

Let’s get down to numbers. As of 2011, this prize has been awarded 101 times to 199 scientists for their research in this field.  In recent years, the Nobel Prize has often been awarded jointly to two or three scientists for either collaborative research or for research that is similar in scope and specialty. Of those 101 occasions, 22 of these awards have been given to 39 researchers for their work in infectious diseases, virology, parasitology and/or immunology. Only one woman is on this list, Françoise Barré-Sinoussi, for her incredible work with Luc Montagnier in identifying HIV at the height of the HIV/AIDS epidemic in the 1980s.

The Nobel Medal for Physiology or Medicine is embossed with the Genius of Medicine "holding an open book in her lap, collecting the water pouring out from a rock in order to quench a sick girl's thirst". Description from NobelPrize. Click for image source.

(FYI, there have been nine years in which the Nobel Prize ceremony and awards did not occur due to the disruption of the two World Wars – in 1915 to 1918, 1921, 1925 and 1940 to 1942. Those Nazi’s again!)

So roughly one-fifth of the Nobel Prizes in medicine have gone to scientists making breakthroughs in the study of infectious diseases or in the immunological response to those diseases, indicating how crucial this particular field of medicine is to the scientific community. We’re not talking dermatology or podiatry here, folks.

In the early years, the Assembly awarded prizes for game-changing advances in the research of big killer diseases of the day – diptheria, tuberculosis and malaria, to name a few. The development of a yellow fever vaccine (1951), discoveries of vital antibiotics that are still used today globally (1939, 1945 and 1952), and the finding that HPV causes cervical cancer (2008) are just a few of the discoveries that the Nobel Assembly considered so revelatory to the field of medicine. Until the past century, how infectious diseases entered the body, their mechanisms of pathogenesis and even their treatment was largely unknown. Malaria is transmitted by mosquitoes? Not known till 1899 and Sir Ronald Ross’s discovery of the parasite hiding inside the stomach of an Anopheles mosquito was justly recognized by the Nobel Assembly in 1902. Lice transmit typhus? Charles Nicolle’s finding won him a good amount of money and worldwide recognition/obscurity in 1928. In 1954, a trio of American researchers were awarded the Nobel for identifying a method to culture the polio virus, launching the beginning of the end of polio’s affliction on humanity.

Many of the awarded discoveries laid the foundation for productive research that has led to profound advancements in disease and pest control, the emergence of the field of public health, development of the pharmaceutical industry and the industrial production of vaccines, antibiotics, and antivirals. Life-changing stuff, ya’ll. Flipping through this list is a reminder of how far we’ve come in the past century in establishing our domain over bacteria and viruses that previously wiped us out with shocking regularity. In fact, some of their findings and methods are so commonplace, hell! even banal, in today’s laboratories that it’s like stepping into a science time-warp reading about their discoveries. Thanks to these scientists, we possess the complex knowledge of genetics, immunology, antibiotics, vaccines and their respective methods to identify, culture and combat new diseases.

The list of winners is below and includes the year they were awarded, their country of origin and the award’s justification from the Nobel Assembly in quotes; those quotes come from the official website of the Nobel Prize. I’ve included in the list a few winners awarded for their work in immunology and antibiotics; while these are not strictly related to infectious diseases, their research laid a strong foundation for future infectious disease work and, well, they’re related and it’s important so get over it.

Scroll past this engrossing list that I’ve compiled for your disease-seeking pleasure.

Emil Adolf von Behring (Germany) “for his work on serum therapy, especially its application against diphtheria, by which he has opened a new road in the domain of medical science and thereby placed in the hands of the physician a victorious weapon against illness and deaths”. Victorious weapon! I’d think the flowery language alone should do the trick. In any case, von Behring developed a diphtheria antitoxin, known as a “serum”, by repeatedly injecting a horse with diphtheria toxin.

"A Future Pharmacy". An editorial cartoon mocking Emil Adolf Von Behring and his discovery of serum therapy, in which a diphtheria antitoxin was developed by repeatedly exposing a horse to the diphtheria toxin. Click for source.

Sir Ronald Ross (United Kingdom) for his discovery that malaria is transmitted by mosquitoes.

Robert Koch (Germany) “for his investigations and discoveries in relation to tuberculosis”.

Charles Louis Alphonse Laveran (France) “in recognition of his work on the role played by protozoa in causing diseases”.

Julius Wagner-Jauregg (Austria) “for his discovery of the therapeutic value of malaria inoculation in the treatment of dementia paralytica”. In 1927, Wagner-Jauregg received the  Prize for his discovery of pyrotherapy, the treatment of mental disease by febrile diseases. Besides being a Nobel Laureate, Wagner-Jauregg was also a Nazi sympathizer, anti-semite and racial hygienist. A charmer of a man who forced sterilization upon the mentally ill and the criminal and the so-called “father of fever therapy”(1).

Mustachioed Wagner-Jauregg stands behind a mental patient receiving malarial pyrotherapy. Click for image source.

Since 1887, he had been investigating the phenomenon of how fever, as induced by tuberculosis or St. Anthony’s Fire, may reduce the effects of psychosis caused by tertiary syphilis. Bacterial infections didn’t seem to do the trick in terms of bringing about recurrent high fevers and so in 1917 Wagner-Jauregg turned to the malaria parasite. Turns out, malaria is an excellent specimen for this sort of thing and led to its usage as an established treatment for paralytic dementia and neurosyphilis. An application of quinine would end the fever therapy, eliminating the infection and leaving the patient free of his psychoses. For this hot discovery, Wagner-Jauregg is the only psychiatrist to have ever won the Nobel for investigative fieldwork on mental illness.

Charles Jules Henri Nicolle (France) for his discovery that lice transmitted typhus. Nicholle was a master researcher of infectious diseases and made many discoveries regarding the pathology and epidemiology of brucellosis, leishmaniasis, measles, rinderpest, scarlet fever, Mediterranean spotted fever, toxoplasmosis, trachoma and tuberculosis. Nicholle’s typhus work was performed in Tunisia using chimpanzees and toque macaques (2).

Vials and tablets of prontosil, an industrial dye discovered to have antibacterial properties by Gerhard Domagk. Click for source.

Gerhard Domagk (Germany) “for the discovery of the antibacterial effects of prontosil”. Prontosil was the first drug to be found effective against bacterial infections and Domagk made quick use of this fact – as a streptococcal infection threatened his daughter, his treatment with prontosil prevented the therapeutic amputation of her arm.

Sir Alexander Fleming (United Kingdom), Sir Ernst Boris Chain (United Kingdom), and Howard Walter Florey (Australia) “for the discovery of penicillin and its curative effect in various infectious diseases”.

Max Theiler Union (South Africa) “for his discoveries concerning yellow fever and how to combat it”. He had an enormous forehead. His award is the only one that has gone towards a virus vaccine.

Selman Abraham Waksman (United States) for his discovery of streptomycin, the first antibiotic effective against tuberculosis”. Waksman coined the term “antibiotic”.

There's really no reason why I'm including this photo of Selman Waksman here aside from the fact that it's so gloriously Science!-y. Lab coat, check. Flask of something liquid, check. Mood lighting, check. Click for image source.

John Franklin Enders, Thomas Huckle Weller and Frederick Chapman Robbins (all from the United States) “for their discovery of the ability of poliomyelitis viruses to grow in cultures of various types of tissue”. Their work laid the groundwork for Jonas Salk’s development of the polio vaccine.

Joshua Lederberg (United States) “for his discoveries concerning genetic recombination and the organization of the genetic material of bacteria”.

Peyton Rous (United States) “for his discovery of tumour-inducing viruses”. In 1911, Rous found that some cancers can be transmitted by viruses, known as retroviruses. Forty years later, he was awarded for his work.

Max Delbrück, Alfred D. Hershey and Salvador E. Luria (all from the United States), “for their discoveries concerning the replication mechanism and the genetic structure of viruses”. The trio discovered that bacterial resistance to bacteriophages (viruses that infect bacteria) was a result of random mutations.

Gerald M. Edelman (United States) and Rodney R. Porter (United Kingdom) used immunoglobins sourced from human blood to identify the chemical structure of antibodies.

Baruch S. Blumberg and D. Carleton Gajdusek (United States) “for their discoveries concerning new mechanisms for the origin and dissemination of infectious diseases”. These guys were awarded for their research on kuru, a disease caused by human prions. Fun fact: Blumberg also discovered the hepatitis B virus and developed the diagnostic test and vaccine for it.

Niels K. Jerne (Denmark), Georges J.F. Köhler (Federal Republic of Germany) and César Milstein (Argentina and the United Kingdom) “for theories concerning the specificity in development and control of the immune system and the discovery of the principle for production of monoclonal antibodies”.

J. Michael Bishop and Harold E. Varmus (United States) “for their discovery of the cellular origin of retroviral oncogenes”.

Stanley B. Prusiner (United States) “for his discovery of Prions – a new biological principle of infection”.

Barry J. Marshall and J. Robin Warren (Australia) “for their discovery of the bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease”. Marshall is famously known for downing culture medium loaded with H. pylori to directly prove that the bacterium is responsible for causing ulcers.

Andrew Z. Fire and Craig C. Mello (United States) “for their discovery of RNA interference, [otherwise known as] gene silencing by double-stranded RNA”.

Harald zur Hausen (Germany) “for his discovery of human papilloma viruses causing cervical cancer”, along with Françoise Barré-Sinoussi and Luc Montagnier (France) “for their discovery of the human immunodeficiency virus”.


The Nobel Prize website has a fleshed-out timeline for every Laureate and includes their biography, a short article about their research, the lecture they delivered to the Nobel Assembly and much much more.

(1) Howes OD et al (2009) Julius Wagner-Jauregg, 1857–1940. Am J of Psy. 166(4): 409.
(2) Schultz MG and Morens DM. (2009) Charles-Jules-Henri Nicolle. Emerg Infect Dis. 15(9): 1520-22. Accessed online.

ResearchBlogging.orgSchultz, M. (2009). Charles-Jules-Henri Nicolle Emerging Infectious Diseases, 1519-1522 DOI: 10.3201/eid1509.090891