Which of the following bacterial disease that is called as spleenic fever ?

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Correct — B, Anthrax. Anthrax is caused by Bacillus anthracis, a large, Gram-positive, rod-shaped, spore-forming bacterium, and it has carried the name splenic fever for well over a century — the stem's 'spleenic' is simply a misspelling of splenic. The name comes from the post-mortem picture in infected herbivores: the spleen is grossly enlarged, dark and soft, so characteristically that veterinarians used it as a diagnostic sign long before the organism was identified. The disease has three other historic names, and each names a route of infection rather than an organ. 'Woolsorter's disease' is the inhalational form, contracted by workers breathing spores from contaminated fleece and hair; 'ragpicker's disease' is the same route from hides; and 'malignant pustule' or malignant carbuncle is the cutaneous form, in which the sore develops a coal-black necrotic centre — the Greek anthrakis, meaning coal, is where the disease's own name comes from. Anthrax also occupies a unique place in the history of medicine. Robert Koch worked out the organism's full life cycle in 1876 and used it to prove for the first time that one specific microbe causes one specific disease, the demonstration behind Koch's postulates. Five years later, in 1881 at Pouilly-le-Fort, Louis Pasteur publicly vaccinated sheep against anthrax — the first public field trial of a bacterial vaccine. (His attenuated chicken-cholera vaccine had come first, in February 1880, and his notebooks show the Pouilly-le-Fort preparation itself was chemically killed rather than live-attenuated.) What makes the disease persist is the spore: B. anthracis forms spores that survive in soil for decades and infect grazing animals long after the outbreak that produced them, which is why anthrax remains a livestock disease of pastoral districts rather than a crowd disease of cities.

Why the other options are wrong — (a) Typhoid is a genuine near-miss and deserves a careful answer. It is caused by Salmonella enterica serovar Typhi, spreads by the faeco-oral route through contaminated water and food, and it does enlarge the spleen — splenomegaly is a recognised sign in the second week, alongside step-ladder fever and rose spots. But its established name is enteric fever, from the ulceration of Peyer's patches in the ileum, and 'splenic fever' has never been used for it.  (c) Cholera is caused by Vibrio cholerae, a comma-shaped Gram-negative bacterium whose toxin drives a massive secretory diarrhoea — the painless 'rice-water' stool that kills by dehydration, not by organ enlargement. Its historical associations are with water supply, from John Snow's Broad Street pump in 1854 to Robert Koch's isolation of the organism in 1883, and it has no splenic name.  (d) This option would only stand if none of the three named diseases were splenic fever. Anthrax is, under a name in continuous use in veterinary and medical texts, so the escape option fails. Reach for 'None of the above' only after positively rejecting every named option, never as a hedge when one of them is unfamiliar.

Concept: A great many diseases are known by an older popular name that describes a symptom, an organ or an occupation, and examiners exploit the gap between that name and the modern one. Anthrax alone has four: splenic fever from the swollen spleen at autopsy, woolsorter's disease from inhaled spores in fleece, ragpicker's disease from hides, and malignant pustule from the black skin eschar. Its clinical forms follow the route of entry. Cutaneous anthrax accounts for the overwhelming majority of natural human cases and is the mildest; inhalational anthrax is the rarest and the most lethal; gastrointestinal anthrax follows eating undercooked infected meat. Because Bacillus anthracis sporulates on exposure to air and its spores endure in soil for decades, anthrax behaves as a soil-borne zoonosis of grazing animals — cattle, sheep and goats infect themselves at pasture and humans are infected from them, not usually from each other. Those same durable spores are what made anthrax the classic agent of biological warfare, as the posted-letter attacks in the United States in 2001 showed.

State PCS 2024 Q39 — Science & Technology PYQ with Answer

State PCS 2024 Q39 — Science & Technology PYQ with Answer