Posts tagged virus
Top: Cow-milker infected from the teats of a cow with natural cow-pox. Large depressed vesicle with a small central crust, tumid (swollen) margin, surrounded by well-marked areola and considerable surrounding induration (hardness associated with swelling)
Bottom: Same case, one week later. Reddish brown crust typical of recovering cow-pox cases, on a reddened elevated and indurated base.
Many mammalian species have members of the Orthopoxviridae that are specialized to exist within their systems - humans have smallpox, cows have cowpox, monkeys have monkeypox, and so on (note: chicken pox is NOT a member of this group - its name comes from an old English word meaning “Itchy”, and is completely unrelated).
However, sometimes, the similar viruses can cross species barriers, as in the case of cowpox. Though the viruses are specialized to their host species enough that they don’t easily spread between atypical hosts, they’re related enough that once an individual is infected with one pox virus, their immune system is able to to recognize and fend off the whole lot of them. This is why, with the assistance of cowpox (Vaccinia) cultures in administered vaccines (rather than all of humanity having to be in direct contact with cows…), smallpox was able to be eradicated in the wild.
A Text-Book of Bacteriology, including the Etiology and Prevention of Infectious Diseases. Edgar M. Crookshank, 1897.
Anatomical Teaching Models
It’s believed that anatomical models have been used for teaching purposes (as opposed to ritualistic or religious purposes) since some point between 100 BCE - 300 CE, since dissection of the dead was a taboo and crime in the Late Greek and Roman empire, and paper or vellum for illustration was much more fragile than, say, carved wooden figures.
However, most of our evidence for anatomical models comes from the late Medieval era and later, when materials such as ivory and sealed papier-mâché were used for many anatomical carvings. Later, especially in the 18th and 19th centuries, wax sculptures were common in medical schools, as much finer detail was attainable with such a pliable substance.
Today, most models used for teaching both lay persons and students are made from thermoplastics and texturing agents, and can range from highly detailed micro-premature babies, to fully-removable models of life-sized animals with every layer of tissue and organs, to huge versions of virions not normally visible except under an electron microscope. Given that the majority of students show greatly increased memory of a subject when able to physically manipulate a representation of it, the use of anatomical teaching models is here to stay.
For more on anatomical models and tons more on the history of medicine, visit the Science Museum: Brought to Life!
Images:
Top: Anatomical structure of reclining woman in early pregnancy. Florence, Italy, ca. 1770.
Center left: Wax model of the human brain, with skin, skull, and meninges removed. Intended for medical students. Western Europe, ca. 1700-1900. Date uncertain.
Center right: Papier-mache model of acupuncture meridians. Japan, ca. 1601-1700.
Bottom left: Sculpture of male black infant, 22-23 weeks development. Created for exhibit on how micro-preemies are kept alive in the modern era. England, 1998.
Bottom right: Model of an adenovirus, magnified 3,000,000x, from electron microscope images. London, England, 1985.
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“Education” is simply a fairly arbitrary measure of what one has had the time, interest, and opportunity to learn. Perhaps the person is a genius when it comes to advanced calculus, or child psychology?
Either way, and somewhat unrelated, I’m generally a very proficient speller, and always have been…but I lost my 6th grade spelling bee in the first round by spelling “judge” G-U-D-J-E. So I can’t NOT understand mixing up the two letters.
Bacteriophages?
At least I believe that’s what you’re talking about. Though evidence of their existence was shown by both Ernest Hanbury Hankin while he was working with cholera (and trying to find anti-cholera agents) in the Ganges River basin in 1896, and Frederick Twort in 1915, the basics of virus structure and function were not definitively shown until nearly 1970, by Delbruk, Hershey, and Luria.
Phages infect and kill bacteria, and are highly specialized for each individual strain of bacteria. Despite their extreme specificity, one institute has taken up studying and producing “phage therapy” treatments since 1923 - the Tbilisi Institute in the country of Georgia. While phage therapy (or “biocontrol”) has proven highly effective in the studies done on it (there were some very large-scale studies done in the Soviet Union, and this isn’t just an alternative nonsense therapy), the very specific nature of phages, combined with the effort it takes to produce enough of them to use in a study, and the time it takes to test each bacterial strain to see which phage to use (often long enough for a patient to die - more than 24 hours for most bacteria), has led to very little testing outside of Georgia and other former Soviet countries.
But the continuing efficacy in the Tbilisi hospitals and Eliava Institute test subjects shows that there is promise for this sort of treatment, if nothing else works. If, for example, an extremely antibiotic-resistant staphylococcus appears (resistant to ALL known antibiotics), this may be the only opportunity to combat it once we produce an effective phage strain - we already know that the standard MRSA bacteria can be quickly eliminated with this virus.
BACTERIOPHAGE!
Bacteriophages on an E. coli cell.
Plush bacteriophage! :D From GIANTmicrobes.
More on bacteriophages:
Animation of how the T4 Bacteriophage works
Tongue and larynx of rabid dog
People once thought that rabies was caused by a worm in the sublingual salivary glands, because of how tight and swollen they become when rabies is infecting the system. We know now that that’s not true. Rabies is caused by a virus that infects the nervous system. Once it enters the body, it seeks out the peripheral nervous system, and moves along peripheral nerve cells until it reaches the CNS. The virus continues up the central nervous system until it reaches the brain, where it multiplies, causes the extreme symptoms, and kills the victim.
Up at the top of this illustration, you can see the inflamed section of the upper throat. This goes along with the involuntary throat spasms that rabies entails, which prevent the ingestion of any liquids. The spasms are often incredibly painful, and the avoidance of liquids (though not a true fear of them) is why rabies used to be called hydrophobia.
Rabies and Hydrophobia: Their History, Nature, Causes, Symptoms, and Prevention. George Fleming, 1872.
“Mad dog in a coffee-house”
Late 18th century illustration by Thomas Rowlandson (1756-1827)
Right lung with surface hemorrhages
Lung moderately enlarged due to influenza. Note the consolidation of infectious activity in the blue area.
The Pathology of Influenza. M. C. Winternitz, Isabel M. Wason, and Frank P. McNamara, 1920.
Early Bronchiolar Lesion in Fatal Influenza
You can see the mucus in the lumen (that open area in the middle), preventing air exchange. There is also inflammation present.
The Pathology of Influenza. M. C. Winternitz, Isabel M. Wason, and Frank P. McNamara, 1920.
A blog for all biological and medical ephemera, from the age of Abraham through the era of medical quackery and cure-all nostrums. Featuring illustrations, history, and totally useless trivia from the diverse realms of nature and medicine.
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