Amboceptor

Microbiological, virological, bacteriological, immunological, medical, epidemiological, historical, anecdotal

Tag: insects

Confusing movie science: S+H+E (1980)

She. A title familiar to millions, from H. Rider Haggard’s 1887 adventure novel that’s had a half-dozen film adaptations, giving actresses like Helen Gahagan and Ursula Andress a chance to be statuesque and intimidating as the titular 2,000-year-old sorceress worshiped by remote tribesmen.she-poster-1979

This is not one of those films. Having bought it along with other 1980s VHS tapes, I expected the 1982 adaptation of Haggard’s novel starring Sandahl Bergman of Conan the Barbarian and Hell Comes to Frogtown fame. Instead, it’s the acronymic S+H+E: Security Hazards Expert, which aired on CBS in February 1980. Filmed on location in “Italy and Berlin”, this was an ambitious attempted pilot for a Charlie’s Angels-esque series about a female secret agent played by Cornelia Sharpe, wife of producer Martin Bregman.

She is as effective as you could hope for as a “Diana Rigg type”. The whole movie is entertaining, despite the random elements that only make sense if there are subsequent episodes (like her Italian boyfriend who wants her to retire and settle down) and the soundtrack consisting of the same song over the opening credits, closing credits, every montage, and every action sequence. Adding to the enjoyment was the single trailer that preceded the movie, for another CBS TV movie starring Dyan Cannon as a madam who was elected mayor of Sausalito, California.

* * *

she-opening

The last thing I expected from this movie was microbiological blog fodder. But after hearing the characters talk about the science that underlies the plot, I had to stop and figure out exactly why it didn’t make sense.

* * *

First, we’re introduced to the wine scientists. The whole movie is on YouTube as of today; start around the 23-minute mark for this conversation. Charming wine magnate Cesare Magnasco (Omar Sharif) is showing our heroine Lavinia Kean around his sinister winery. Frau Doktor Biebling is played by sixties icon Anita Ekberg, in what I believe was her last English-language role.

  • Cesare: Miss Blake, this is our distinguished oenologist, Frau Doktor Biebling.
  • Lavinia: How do you do?
  • Biebling: (silence)
  • Cesare: Dr. Biebling is a genius. A Nobel Prize nominee in parasitology from the University of Heidelberg. Doctor, tell Miss Blake what we do here.
  • Biebling: We are approaching a very critical phase in our latest experiment, Barone. It requires concentration and my closest attention.
  • Cesare: Per favore. For her American readers. To make them drink more Magnasco!
  • Biebling: Our chief concern is to protect the vines. Particularly from a genus of insects of the family Phylloxera.
  • Lavinia: Which of the 32 known species do you specialize in?
  • Biebling: (silence)
  • Cesare: They destroyed millions of acres of grapes when first brought to Europe.
  • Biebling: (withering stare) From America.
  • Lavinia: (smirking) I’m terribly sorry! I won’t disturb you any longer.
  • As they leave Biebling’s lab, Magnasco points to two Petri dishes, saying “Experimental cultures”. Another scientist asks Biebling mockingly, “Why don’t you develop an anti-jealousy microbe?”

The issue here is the word “parasitology”. Although the Phylloxera family of aphids do act as parasites to grapevines, someone who studies them would be an entomologist. Parasitology generally refers to parasites of animals — especially worms or microscopic eukaryotes like malaria, Toxoplasma or Giardia. Wikipedia claims it also refers to organisms like fleas and lice, but even this only extends to parasites of animals, not plants.

It’s possible that instead of being an expert on aphids, she is an expert on microscopic parasites of aphids. This hypothesis is supported by the “experimental cultures”, which look like bacterial broth. However, I don’t think there are any such microbes, whether eukaryotic or bacterial. There are methods of aphid control using aphid parasites… but those parasites are tiny wasps. So either way, she’d be an entomologist!

Finally, calling someone a “Nobel Prize nominee in parasitology” sort of implies that there is a Nobel Prize in Parasitology, which there isn’t. And although it is prestigious to be nominated for a Nobel Prize, it’s not quite like the Academy Awards. The 2014 Nobel Prize in Physiology of Medicine had 263 nominees.

* * *

But this is mere pedantry. The really confounding exchange is near the end, around minute 73. By now, the good guys have learned that Magnasco & Co. are holding the world’s petroleum supply hostage with something called “A.P.M.” Lavinia Kean, and her assistant/minder/colleauge Lacey (basically Bosley from Charlie’s Angels), have snuck into Frau Doktor Biebling’s laboratory again. They snoop around, and when they’re discovered, Lavinia injects Biebling with some sort of sedative, injected via flying mechanical bug.

  • Biebling: You again!
  • Lavinia: Do unto others… darling.
  • Biebling: I should have put you to sleep permanently. (passes out)
  • Lacey: (points to page of notes) “Anti-Petroleum Microbe”?
  • Both together: A.P.M.!
  • (she smears the orange liquid from one of the cultures on a slide, and they look at it under a microscope. Wriggling animalcules are seen through the lens)
  • Lavinia: There it is. A simple amoeba-type microbe found in tide pools. Elsa’s a parasitologist, but she wasn’t working on Phylloxera. She was developing A.P.M.
  • Lacey: I’m lost.
  • Lavinia: She fed and refined the algae with special nutrients. Now it’s a virulent strain that devours petroleum.
  • Lacey: I’m still lost.
  • Lavinia: When A.P.M. is mixed with petroleum it multiplies like crazy. Gasoline is refined petroleum.
  • She goes on to demonstrate how gasoline is flammable, but when mixed with A.P.M. it goes all foamy and inert.

This makes it clear that Frau Doktor Biebling is an expert on microbes, not so much on aphids.

This is gasoline. This is gasoline on A.P.M.

This is gasoline. This is gasoline on A.P.M.

Her work for Magnasco has been a matter of encouraging a certain microbe to grow on different substrates, akin to the classic experiments in microbial evolution where bacteria start to thrive on some molecule that used to poison them. With “A.P.M.”, they have made a microbe which “devours petroleum”, rendering it a foamy mass of uselessness. The notion of microbes engineered to eat hydrocarbons has been invoked for decades, generally as a good thing (cleaning up oil spills). Here it’s presented as a sort of plague, which if it ever enters a pipeline will spread and spread until it consumes our entire inexorably interconnected petroleum supply.

dave-barry-oil-slicks

In a column from the 1980s, Dave Barry sees petroleum-eating microbes as neither plague nor panacea.

One problem here is that the new, oil-eating microbe is described as a “virulent strain”. That’s not what “virulent” means. A virulent strain would be one that is particularly harmful or deadly to the organism it infects. A.P.M., though scary, isn’t infecting anything — it’s just consuming certain nutrients.

And then there’s that word “parasitologist” again.

It seems that in the world of this movie, vines are protected against aphids by spraying them with an infectious agent that kills the bugs. So she could be a “parasitologist”, if the infectious agent is eukaryotic rather than bacterial.

A.P.M. under the microscope

A.P.M. under the microscope

Amoeba proteus (click for source)

Amoeba (click for source)

And indeed, it’s described as “a simple amoeba-type microbe”. Judge for yourself if that view through the microscope shows an amoeba-type microbe. What are some other possibilities? They appear filamentous, but not rigid enough to be filamentous bacteria, and I don’t see the branching that would indicate fungal hyphae. Maybe they are fragments of some larger structure. Could these be strands of filamentous algae, but photographed in a way that washes out the color?

Yes! In addition to being an amoeba, A.P.M. is described as “algae”. It normally lives in tidal pools, but has been acclimated to life in petroleum. And here I admit a misconception of my own: I thought algae would be a poor choice for evil scientists seeking speedy evolution of new abilities, compared to bacteria. But this might not be the case – Bradley Olson’s evolutionary biology lab at Kansas State, for example, uses algae as a model organism.

The question now has to be asked: Does Frau Doktor Biebling do any work at all related to grapevines? What did she promise to do in her grant proposals?

* * *

To read about a real-life salt-loving microbe that eats oil slicks, go to the MicrobeWiki entry on Alcanivorax.

To learn more about colorless algae that are also amoebae, infectious parasites of oil and studied by entomological oenologists, watch S+H+E.

Follow Amboceptor on Twitter: @AmboceptorBlog

"The only way to deactivate A.P.M. is to freeze it in CO2, put it in metal containers and sink it in the Artic Ocean."

“The only way to deactivate A.P.M. is to freeze it in CO2, put it in metal containers and sink it in the Artic Ocean.” William Traylor (Lacey) and Cornelia Sharpe (Lavinia Kean) in S+H+E

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Yellow fever stops at the Miami airport.

staining-mosquitoes-before-liberating

Initially, new infectious diseases could spread only as fast and far as people could walk. Then as fast and far as horses could gallop and ships could sail. With the advent of truly global travel, the last five centuries have seen more new diseases than ever before become potential pandemics. The current reach, volume and speed of travel are unprecedented, so that human mobility has increased in high-income countries by over 1000-fold since 1800. Aviation, in particular, has expanded rapidly as the world economy has grown, though worries about its potential for spreading disease began with the advent of commercial aviation. [1]

Podcasts are great. But in the world of science podcasts, many are simply boring because there is only one person talking, or one person interviewing another person. Unless it’s slickly produced and edited (the Nature or Science Times podcasts), I’ll quickly lose interest.

It’s better when the podcast is three or four people who know each other, having a conversation. This is is the format of the TWi[X] series, particularly the flagship This Week in Virology. TWiV co-host Dickson Despommier, though not a virologist, contributes a big-picture point of view when the show leaves its territory of basic lab science and moves into epidemiology and patterns of disease outbreaks. Here’s his lecture on how West Nile arrived in North America and spread from state to state, energized by a very hot summer at the Bronx Zoo.

More than once I recall Dr. Despommier pointing out that though it’s all well and good to model how a epidemic might spread by looking at the day-to-day movements of people and mosquitoes, the most powerful and mobile disease vector is… the airplane.

That fact has become ever more clear with the SARS and West Nile outbreaks, as we used genetic analysis to track them across the continents in real time. But you might be surprised at how long ago people recognized the airplane as a challenge to disease control.

* * *

80 years ago, yellow fever was the archetypal mosquito-transmitted disease. Particularly as the disease was endemic in some parts of the world (e.g. South America), but not in others (e.g. North America), despite both places being home to the vector, Aedes genus mosquitoes. A 1934 article [2] coauthored by Henry Hanson, veteran of battles against yellow fever on three continents, points out that dengue fever (also transmitted by Aedes) had reappeared in Florida after an eleven-year absence, and yellow fever could do the same at any time.

dengue-1922-1934-tampa-miami

Hanson and coauthor T. H. D. Griffitts go on to chide the cities of Florida and Georgia for their complacency in providing countless unsupervised water vessels in which the mosquitoes can reproduce.

Practically every urban community in the South has its array of artificial containers, from flower vases to catch basins, cuspidors and discarded automobile tires, producing Aedes aegypti. For example, the city of Tampa in eight weeks reported finding 1,091,823 containers (potential mosquito “hatcheries”). Of these, larvae were found in 20,864, or approximately 2 per cent. This was an unusually dry season (average rainfall of 1 1/2 inches a month for this period). It is interesting to note that in Miami for a like period only 56,598 potential breeding containers were reported, with 38,401, or 68 per cent, of the total actually breeding.

So I made an error above. The vessels aren’t quite “countless”. There are 1,091,823 of them in Tampa, give or take a dozen.

Though concerned that yellow fever could reach North America (again), Hanson and Griffitts are more concerned about India. The disease is only known in jungle areas of Brazil, Colombia and Bolivia (they claim); by comparison, Africa is its ancestral “home” and India, fairly nearby by plane, is virgin territory for yellow fever epidemics.

Today there is a feeling of concern … that Old World territory, where the vectors abound and where yellow fever has never before stalked, may experience widespread and devastating epidemics. One infective mosquito traveling in an airplane from the home of yellow fever (Africa) to India could be the spark to start the conflagration.

Thus there was considerable surveillance for mosquitoes and infected passengers at airports worldwide.

The earliest article I can find specifically discussing airplanes as disease vectors is from 1930, the first [3] of two identically titled 1930s editorials in the American Journal of Public Health. I don’t know if the international rules discussed here were enacted, but they show awareness that quarantine and disinsectization measures developed for ocean travel need to be multiplied and intensified to cope with passenger aircraft. Click for a bigger view.

airplane-and-yellow-fever-1930

* * *

For the purpose of determining whether or not mosquitoes are carried in airplanes, and, if so, to what extent, the distance of such transportation, the species of mosquitoes, and the type of planes on which they are carried, the United States Public Health Service began, on July 23, 1931, the inspection of all airplanes from tropical ports arriving at the airports of the Pan American Airways System at Miami. [4]

An anecdote from less than a year later illustrates how the search for mosquitoes had become a normal part of a plane’s arrival in the U.S. from South America.

A very Normal Rockwell scene of mosquito inspection. From LIFE Magazine, 5/27/40.

A very Normal Rockwell scene of mosquito inspection. From LIFE Magazine, 5/27/40.

The story of “the first international aerial hitchhiker” is as follows.

Paul Kaiser, 25, tried to immigrate from Czechoslovakia to America via a circuitous route. First, he got to the German port of Bremen, from which he sailed to Colón, Panama on an ocean liner. Sneaking into the nearby Canal Zone airport, he climbed into the baggage compartment of a “big 22-passenger Commodore plane”. The plane first landed in Barranquilla, Colombia, where he was not detected. It then landed in Kingston, Jamaica, where he was not detected. Finally, after Kaiser had spent 2 days without food, he landed in Miami. However, in Miami “a very thorough inspection is given every plane for mosquitoes, for there is always danger of the deadly yellow fever mosquito surviving the short trip and landing in the United States, a most undesirable immigrant”. Check out the April 1933 issue of Flying magazine for more details.

A few months earlier, T.H.D. Griffitts (coauthor of the aforementioned Henry Hanson article) performed the first experiments on mosquito transport by aeroplane. These were published in late 1931, in an enjoyably conversational article in Public Health Reports [4].

Dr. Griffitts, you don't really have to describe the experiments you WANTED to do but then decided were unnecessary.

Dr. Griffitts, you don’t really have to describe the experiments you WANTED to do but then decided were unnecessary.

T.H.D. Griffitts (and J.J. Griffitts — his son?) start out by describing all the mosquitoes observed on normal commercial flights between July and September of 1931. Most were Culex quinquefasciatus, but several other species were observed including Aedes aegypti. In fact, a later Griffitts paper [5] indicates that the historic first mosquito discovered on a Miami-bound plane was Aedes aegypti. (It’s somewhat confusing that the insect apparently arrived on a “ship from San Salvador, El Salvador”, but I think that at this time the word “ship” could be used for aircraft. And San Salvador is definitely not a port city.)

Griffitts also put mosquitoes on three planes departing from San Juan, Puerto Rico, and looked for them upon arrival in Miami. Today it takes 2.5 hours to fly from SJU to MIA, but in 1931 they stopped at three other airports along the way and the average travel time was over 10 hours. A total of 100 mosquitoes were labeled with eosin dye (to distinguish them from non-experimental and Miami-resident mosquitoes). 22 were observed upon arrival in Miami, after 1,250 miles of flying, opening of doors and hatches, loading and unloading of luggage, etc. It seems obvious that the insects can be imported… but these experiments prove it.

* * *

Eight years after 1930’s “The Airplane and Yellow Fever” editorial, the American Journal of Public Health published another one [5], describing the policies for infectious mosquito control in Khartoum, Miami, and “the French Colonies and Mandates”.

As the 1930s progressed and India remained devoid of yellow fever, public health doctors kept amplifying their alarms about how devastating such an epidemic would be. From the 1938 editorial:

greatest-menace-in-the-world-today

75 years after that was published, yellow fever still hasn’t swept through India.

In 1938, the number of people who’d been vaccinated against yellow fever was less than a hundred thousand, mostly in Brazil. It had taken a long time to make a vaccine strain of YFV that was weak enough that it could be given as a live vaccine, but the 1938 trial (run by the Rockefeller Foundation) was successful, and in 1942 the number of people vaccinated was over 10 million. For his two decades of work on the vaccine, which along the way required multiple basic science breakthroughs for it to be manufactured in large quantities, Max Theiler of Rockefeller University received the 1951 Nobel Prize in Physiology or Medicine. Read more here [6] about Theiler’s story; read more here [7] about the many problems and hurdles that were overcome to end up with a safe vaccine. (I think the second one is open-access and the first one isn’t.)

Within a decade, though complications from the vaccine were common and the virus stayed endemic in the tropics, Theiler’s YFV vaccine had eliminated yellow fever as a source of large-scale epidemics.

* * *

Coda: As early as the airplane was recognized as a vector for disease… it was harnessed as a weapon against disease.

From a 1932 report in Science (8), Joseph Ginsburg of the New Jersey Agricultural Experiment Station explains how large regions of standing water that previously were inaccessible to mosquito control workers can now be reached by plane, so that the surface can be coated with larvicidal pyrethrum or oil.

cheesequake-killing-film

 

* * *

1. Tatem AJ, Rogers DJ, Hay SI (2006). Global transport networks and infectious disease spread. Adv Parasitol 62:293-343.

2. Griffitts THD, Hanson H (1934). Significance of an epidemic of dengue. JAMA 107(14):1107-1110.

3. Editorial (1930): The airplane and yellow fever. Am J Public Health 20(11):1221-1222.

4. Griffitts THD, Griffitts JJ (1931). Mosquitoes transported by airplanes: Staining method used in determining their importation. Public Health Rep0rts 46(47):2775-2782.

5. Editorial (1938): The airplane and yellow fever. Am J Public Health 28(9):1116-1118.

6. Norrby E (2007). Yellow fever and Max Theiler: The only Nobel Prize for a virus vaccine. J Exp Med 204(12):2779-2784.

7. Frierson JG (2010). The yellow fever vaccine: A history. Yale J Biol Med 83(2): 77-85.

8. Ginsberg JM (1932). Airplane oiling to control mosquitoes. Science 75(1951):542.

 

Data Update: Look at the polio fly

In our last Data Update, the table that I turned into figures was not a bad table. It was pretty clear. It just contained some unnecessary information, and was spread across two pages, which is always bad. Today, the table in question is really hard to interpret. I could not make heads or tails of it without going over the text, piece by piece. It’s from a 1943 paper (1) in the Journal of Infectious Diseases.

* * *

Like the pictures of cockroach feeding contraptions, this data comes from a laboratory that was using what could be called “experimental epidemiology” techniques, to figure out how much of a public health hazard these bugs really are. To see if bugs could actually ingest, preserve, and spread germs.

This time the bug is the common house fly. Thomas Francis Jr. had just joined the faculty of the University of Michigan from NYU, and with technician Robert Rondtorff he conducted this study in the interest of public health. Soon Francis would be supervising graduate student Jonas Salk, with whom he worked a lot in the 1940s and 1950s, as you might be able to guess from the fact that Dr. Francis now has a Wikipedia page.

By 1943 we knew that polio was spread by filth and tainted water (the fecal-oral route, as we call it). But flies feed on that stuff, and fly around. Does the virus replicate inside the flies, like malaria? This paper established that when flies ingest poliovirus, the virus disappears from the digestive system within 2 days. And therefore, flies probably aren’t making the poliomyelitis epidemic worse. The significance of these findings is indicated by the introduction to a 1950 paper (2) by children’s television character “Herbert Hurlbut”.

Poliomyelitis virus has been isolated from filth-frequenting flies caught in nature during several epidemics in recent years.(3-5) When the Lansing strain of the virus was fed to house flies under experimental conditions, virus was not recovered after 48 hours.(1,6) Recently Melnick and Penner (7) fed virus in human stools to the blowfly Phormia regina and were able to recover it from the flies after about two weeks[.]

* * *

First of all, their experimental system. Feed the flies on polio-infected material. To make sure there was a lot of polio in the flies’ diet, they did not use excrement from polio-infected animals. They used “a 10% suspension of infected [mouse] spinal cords in boiled milk”. In the not-entirely-robotic prose of scientific papers of the era, they say they “offered” this to the flies. Earlier they had just diluted the mashed spinal cords in saline solution, and the flies “did not feed readily”, so they switched to a solution in milk, which the flies found far more appealing.

For this experiment, the flies enjoyed their neuronal polio-milk for 1 hour, after which it was removed and they were allowed to feed on regular milk if they wanted to. The scientists then waited either 0, 2, 7, 13, 25, 49, 120, 240, or 480 hours. After each of these periods, a certain number of flies were killed, and their abdomens were cut away from the rest of the body. Earlier in the paper it had been established that poliovirus does not leave the abdomen (gut) of an infected fly and reach the rest of the body (thorax and head). Now they are looking to see how much polio virus is in the infected flies.

To get an extract containing poliovirus, they took the fly parts and ground them in saline solution using a mortar and pestle. For best results, they ground the samples with alundum (an abrasive preparation of aluminum oxide). They added some ether (diethyl ether, I assume) to the solution, and let it sit in the refrigerator until it was “bacteriologically sterile”. I’m not familiar with the use of ether to remove bacteria, but it looks very suitable to this procedure.

Experimentally and clinically, ether, whether in its vaporous or liquid state, has been proved to have a bactericidal action. Spore bearing organisms, however, are strongly resistant to it. (7)

Not only did ether treatment remove bacteria from the extract, but it also removed most other viruses. Poliovirus, as a non-enveloped virus, is resistant to ether, a substance which destroys the membranes of enveloped viruses. Here’s a table that summarizes, as of 1949 (8), which viruses are ether-resistant.

andrewes-horstmann-ether

from Andrewes and Horstmann (1949)

Note that most viruses are ether-sensitive and should be removed by this sort of treatment, meaning you’re left with polio, papilloma, bacteriophages, and a few other viruses. Including some, but not all poxviruses, for reasons that are unclear to me. Parapoxviruses (myxoma, BPS virus) are ether-sensitive, and orthopoxviruses (smallpox, vaccinia) are ether-resistant, which is still the dogma (see Chapter 21 of Medical Virology). And chordipoxviruses are maybe one or maybe the other. The above table puts sheep-pox and goat-pox (chordipoxviruses) in the resistant group, whereas Plowright and Ferris (9) say that sheep-pox (SP) and lumpy skin disease (LSD) viruses are ether-sensitive.

from Plowright and Ferris (1959)

from Plowright and Ferris (1959)

Anyway, poliovirus is definitely ether-resistant. So this extraction method is useful for studying this particular virus [here’s another example (10)].

It wasn’t possible in 1943 to measure the amount of virus by using a plaque assay, as we do now (applying a solution of virus to a plate of cells and seeing how many plaques [empty spots] form in the cells by being killed by virus). What the authors do instead is infect mice with the fly extract and see if they become paralyzed and/or dead. In Table 1 they established that the virus survives in the flies, but only in the abdomens. Here’s Table 2.

rondtorff-table-2

So one half of the table is data from the flies, and one half is data from the mice, right? That’s what I thought. But no. This table is made up of almost entirely unnecessary information, and only makes one point. I’ve taken the liberty of highlighting the important parts.

rondtorff-table-2-2

In the text, Rendtorff and Francis go into great detail about how they prepared the ground fly mixtures so they could be compared fairly. They weighed the samples before grinding, and added more or less saline depending on how many fly abdomens were in the sample, and what their weight was. In deciding how much saline to add to dilute the sample, they also factored in what the average unfed weight of an abdomen should be, which should be the same for all the flies. This process was to normalize the data, which could be thrown off by the flies’ unequal eating and excreting habits. I feel like pooling together somewhere between 44 and 66 fly abdomens would already take care of the issue of some flies eating more than others, but they did this statistical technique to account for possible variation.

Most of this table is the raw data they used to do the normalization. But… I don’t need to know what the weight of the fly abdomens were. Or how much saline was added. And I definitely don’t need the “Calculated Unfed Weight of Abdomens” column, which is nothing but the “No. of Flies Sampled” column multiplied by the average weight of an unfed abdomen. It’s good to present raw data, I guess. But this data is not important. Maybe it should be separated from the important data.

The least important data of all is the dates on which the experiments were performed. This is something that absolutely never shows up in research articles anymore. In fact, we may have gone too far in the opposite direction, pretending that we did experiments in a certain order because it makes for a better narrative.

All that matters here is two independent variables and one dependent variable. The independent variables are:

  • Temperature of the incubators in which the flies were living, eating and loving life. (25, 30, or 35 °C)
  • Number of hours the flies were allowed to live, between eating the polio-infected meal and being killed. (0, 2, 7, 13, 19, 25, or 49 hours)

The dependent variable is:

  • Time of death (or paralysis) for a mouse injected with fly extract

So all we really need is a bunch of survival curves.

polio-survival

Figure 2: Poliomyelitis virus is destroyed by the fly digestive tract within 2 days, irrespective of temperature. Flies were fed on a suspension of infected spinal cord in milk for 1 hour. Flies were then incubated in a chamber at 25, 30, or 35 degrees Celsius, for 0 (positive control), 2, 7, 13, 19, 25, or 49 hours. At each timepoint, between 45 and 65 flies in each chamber were killed, and abdomen tissue was extracted using ether. After dilution in saline and evaporation of the ether, each sample was used for intracerebral infection of 9 or 10 mice. Twice a day, mice were monitored for death or paralysis.

* * *

1. Rendtorff RC, Francis T Jr (1943). Survival of the Lansing strain of poliomyelitis virus in the Common house fly, Musca domestica L. J Infect Dis 73(3):198-205.

2. Hurlbut HS (1950). The recovery of poliomyelitis virus after parenteral introduction into cockroaches and houseflies. J Infect Dis 86(1):103-104.

3. Trask JD, Paul JR (1943). The detection of poliomyelitis virus in flies collected during the epidemics of poliomyelitis. J Exp Med 77:531-544.

4. Sabin AB, Ward R (1941). Flies as carriers of poliomyelitis in urban epidemics. Science 94:590-591.

5. Melnick JL (1949). Isolation of poliomyelitis virus from single species of flies collected during an urban epidemic. Am J Hyg 49:8-16.

6. Bang FB, Glaser RW (1943). The persistence of poliomyelitis virus in flies. Am J Hyg 37:320-323.

7. Saliba J (1918). Ether therapy in surgical infections and its effect on immunity. New York Med J 107:157-160.

8. Andrewes CH, Horstmann DM (1949). The susceptibility of viruses to ethyl ether. Microbiology 3(2):290-297.

9. Plowright W, Ferris RD (1959). Ether sensitivity of some mammalian poxviruses. Virology 7(3):357-358.

10. Ward R, LoGrippo GA, Graef I, Earle DP Jr (1954). Quantitative studies on excretion of poliomyelitis virus: A comparison of virus concentration in the stools of paralytic and non-paralytic patients. J Clin Invest 33(3):354-357.

Gallery: Cockroach feeding contraptions

Cockroaches are disgusting. The presence of roaches indicates squalid and germ-ridden conditions. However… do the roaches themselves contribute to the pestilence? Or are they merely a symptom? Or perhaps they are actually beneficial, as they might be able to destroy the germs in their digestive tract.

This is the sort of question that scientists needed to answer. Dr. Stanley Wedberg (1913-2003) of the University of Connecticut created an optimal system for such studies. The cockroach would be immobilized on a block of paraffin in what looks like a comfortable reclining position. This was suited for controlling its food intake to contain known amounts of bacteria, and monitoring its excretions to see how much bacteria remained.

Published in 1947, his system was based on one demonstrated a year earlier by Hubert Frings, a postdoc at Edgewood Arsenal in Maryland. What?

Yes, Edgewood Arsenal, now part of the Aberdeen Proving Grounds, was basically the US Army’s chemical plant, and included a Medical Research Laboratory, which in turn included a division of entomology and insect physiology for some reason. Hubert Frings’s mentor was the head of entomology, Dr. Leigh Chadwick.

Anyway, Frings (who was later quoted in Sports Illustrated on the subject of how to keep birds away from rocket sleds) was using fixed feeding rigs to get insects to ingest chemicals, to measure toxicity. In the paper that demonstrated the cockroach apparatus, his aims were even less sinister, basically looking at which salt solutions cockroaches prefer to drink, and figuring out how high of a concentration is necessary for roaches to prefer sucrose to water.

Wedberg improved the mechanism by putting the roach on its back, which reduced regurgitation and made it more comfortable (yes, both papers use the word “comfort” with regard to how the roach feels). And just as significantly, he decided to use a different roach species, one that was bigger (meaning food and excreta could be measured more accurately), more docile, and had a broad, flat body type well suited for attaching to a block of paraffin.

Wedberg’s choice of Blaberus cranifer as the experimental model cockroach did not catch on, but his technique did, and therefore many subsequent papers just referred to Wedberg and Clarke (1947) or Wedberg, Brandt and Helmboldt (1949) instead of including their own pictures of their own roach restraint systems. But several scientists did seek to show the reader what their apparatus looked like.

Here are a few such pictures. There are probably a lot more in the hardcore entomology journals (J Med Entomol, J Econ Entomol) whose archives I can’t access.

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From Frings H (1946), Gustatory thresholds for sucrose and electrolytes for the cockroach, Periplaneta americana (Linn.). J Exp Zool 102:23-50.

roach-frings-1946

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From Wedberg SE, Clarke NA (1947), A simple method for controlled experimentation on the passage of microorganisms through the digestive tract of insects. J Bacteriol 54:447-450.

roach-wedberg-1947

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From Mackerras IM, Pope P (1948), Experimental Salmonella infections in Australian cockroaches. Austral J Exp Biol Med Sci 26:465-470.

roach-mackerras-1948

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From Wedberg SE, Brandt CD, Helmboldt CF (1949), The passage of microorganisms through the digestive tract of Blaberus cranifer mounted under controlled conditions. J Bacteriol 58(5):573-578.

roach-wedberg-1949

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From Leibovitz A (1951), The cockroach, Periplaneta americana, as a vector of pathogenic organisms. I. The acid-fast organisms. Bulletin of the Pan-American Sanitary Bureau 30:30-41.

roach-leibovitz-1951

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From Julseth RM, Felix JK, Burkholder WE, Diebel RH (1969), Experimental transmission of Enterobacteriaceae by insects. I. Fate of Salmonella fed to the hide beetle Dermestes maculatus and a novel method for mounting insects. Appl Env Microbiol 17(5):710-713. [Well, they look like roaches. Small roaches.]

roach-julseth-1969

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From Klowden MJ, Greenberg B (1976), Salmonella in the American cockroach: Evaluation of vector potential through dosed feeding experiments. J Hyg, Camb 77(1):105-111.

roach-klowden-1976

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