Tag: George Dunea
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Sand flies, leishmaniasis, and kala-azar
Sand flies are about three millimeters long and gray, brownish or golden, with long, piercing mouthparts adapted for sucking blood from their hosts. These seemingly innocuous creatures, classified as belonging to the genus Phlebotomus or Lutzomyia, have long legs and hairy wings held in a vertical V-shape when at rest. They seek moist resting places…
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Fasciola hepatica, the liver fluke of sheep and cattle
The liver flukes Fasciola hepatica and gigantica are parasitic infections that affect humans and animals—cattle, sheep, and goats—in all inhabited areas where they are raised, on all continents, and in over eighty countries. People acquire the disease by eating raw vegetables such as watercress that have been contaminated by one of thirty species of snails,…
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Tapeworm tribulations
Taenia saginata, solium, and asiatica are three related species of tapeworms, each with its own lifecycle, mode of transmission, and clinical implications. The adult tapeworms cause few symptoms, but their larvae can be more troublesome. These parasites have afflicted mankind for thousands of years, perhaps when switching from large carnivores to less dangerous hosts such…
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Trachoma: Contained but not yet subdued
Trachoma is a chronic eye infection caused by Chlamydia trachomatis, a bacterium at first thought to be a virus because of its minuscule size. It is the most common infectious cause of blindness worldwide, striking repeatedly in early childhood and, until recently, blinding millions.1 In 1907, Ludwig Halberstadter and Stanislaus von Prowazek observed the causative…
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Echinococcus granulosus, the sheepdog worm
In the days when Britain ruled the waves and its colonies, some sheep from Thomas Hardy’s Wessex and other counties followed their masters to the antipodes instead of stupidly jumping off a cliff.1 They multiplied in the sun and produced much wool, some of which was later returned to England under the imperial preference system…
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The eponymous tumors of the kidney: Wilms and Grawitz
In a time when diseases were often named after the first person to describe them, kidney tumors were classified into Wilms tumors for children and Grawitz tumors for adults. Both names supposedly honored the memory of these pioneers, and unlucky candidates sitting for medical examinations were sometimes expected to know who these people were. Max…
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Filariasis and elephantiasis, plagues of the tropics
Imagine being bitten by a mosquito, not in your hometown but in one of the countries you have always longed to visit. After a few days, you may not feel well. This is because you have been invaded by the tiny micro-larvae offspring of a worm that lives in another person. You may or may…
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Rabies, still a deadly disease
The man recovered of the bite,The dog it was that died!—Oliver Goldsmith Unfortunately, this is untrue! An estimated 60,000 people die each year from rabies and most cases are due to dog bites. Rabies affects largely the poor rural populations of Africa and Asia, in India, Pakistan and Bangladesh, in Sri Lanka and Thailand, the…
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Fugu—Japanese delicacy or death?
In Japan, fugu has been a “captain of these men of death” for generations, causing an exitus that is “rapid and violent.” There is at first numbness around the mouth, then paralysis, and, as with curare, consciousness persists until the very end. The poison interferes with the transmission of signals from nerves to muscles by…
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Thalassemia
David GreenGeorge HonigGeorge DuneaChicago, Illinois, United States The thalassemias comprise a large and diverse group of genetic disorders which share as a common feature a deficiency, or in the most severe forms a total absence, of one or more of the globin chains of hemoglobin. It was first recognized as a clinical entity distinct from…