Walk the Barnyard
Each station is one exposure. In Explore, tap an animal to open its dossier. In Name That Bug, read the clue and tap the creature that matches. Labels sit outside the figure so nothing gets lost in the hay.
Stop memorizing nine random bugs. Memorize the exposure. The animal in the stem hands you the organism before you read a single lab value. Fur and hides means anthrax. Rabbit and tick means tularemia. Flea off a rodent means plague. Find the animal, name the bug.
The Livestock Lineup
One card per bug. Tap to flip for the gram stain, the buzzword, and why that exposure does it. Clinical photos are real and open full screen.
Tap a card to flip. Tap again to close.
Bacillus anthracis
Gram: Gram-positive boxcar rods in chains, spore-forming.
Buzzword: Painless black eschar with a necrotic center and marked non-pitting edema. Inhaled spores cause woolsorters disease with a widened mediastinum.
Why: Spores survive for years in animal wool, hair, and hides.
Treat: Ciprofloxacin or doxycycline.
Francisella tularensis
Gram: Tiny gram-negative coccobacillus, intracellular. Needs cysteine-enriched media to grow.
Buzzword: Ulceroglandular disease, a tender ulcer with tender regional nodes. Famously low infectious dose.
Why: Skinning infected rabbits or a tick or deerfly bite.
Treat: Streptomycin or gentamicin.
Yersinia pestis
Gram: Gram-negative rod with safety-pin bipolar staining on Giemsa or Wright stain.
Buzzword: Painful buboes in bubonic plague. Southwest United States, prairie dogs and rodents.
Why: Flea bite from a rodent reservoir.
Treat: Streptomycin or gentamicin.
Brucella
Gram: Gram-negative coccobacillus, intracellular, slow-growing.
Buzzword: Undulant fever that rises and falls, drenching night sweats, and granulomas. Farmers, vets, abattoir workers.
Why: Unpasteurized milk or cheese from cattle and goats.
Treat: Doxycycline plus rifampin.
Pasteurella multocida
Gram: Gram-negative coccobacillus, oral flora of cats and dogs.
Buzzword: Rapidly progressive cellulitis with pus within 24 hours of a bite.
Why: Inoculated by the bite itself.
Treat: Amoxicillin-clavulanate.
Bartonella henselae
Gram: Gram-negative rod, seen with Warthin-Starry silver stain.
Buzzword: Tender regional lymphadenopathy after a kitten scratch. Bacillary angiomatosis in HIV.
Why: Kitten scratch or flea-contaminated claws.
Treat: Azithromycin.
Leptospira interrogans
Gram: Hook-ended spirochete, too thin for Gram stain. Seen on darkfield.
Buzzword: Flu-like illness with calf myalgias and conjunctival suffusion. Severe form is Weil disease: jaundice plus acute kidney injury. Surfers and triathletes.
Why: Fresh water or mud with animal urine.
Treat: Penicillin or doxycycline.
Coxiella burnetii
Gram: Tiny intracellular gram-negative. Highly infectious aerosol, environmentally hardy spore-like form.
Buzzword: No vector, no rash. Atypical pneumonia, and culture-negative endocarditis.
Why: Inhaled birth fluids from parturient sheep, goats, and cattle.
Treat: Doxycycline.
Erysipelothrix rhusiopathiae
Gram: Gram-positive rod.
Buzzword: Erysipeloid, a violaceous, well-demarcated, painful hand lesion in fish handlers and butchers.
Why: Skin inoculation handling fish, meat, or swine.
Treat: Penicillin.
Clinical Images
Real images via Wikimedia Commons. Tap any to expand. These are reference photos with no markers placed on them.
The Black Eschar Lock
This is the one students miss. A painless black eschar with a necrotic center, animal fur or hides, and boxcar gram-positive rods is anthrax. Not the vector-borne bugs. Not Staph.
Run the Fork
A black or ulcerated lesion walks in. Answer each fork before it reveals.
Three forks, one answer. Painless. Hides. Boxcar rods. Miss the painlessness and you chase a spider or a Staph abscess and you are wrong. Know your clues.
Sort the Barn by Gram Stain
The slide narrows it fast. Tap a bug, then tap the bin where it belongs. Anthrax and Erysipelothrix are the only gram-positives in this barn.
The Whole Barn on One Card
Self-test: the disease column is blurred. Tap the table to reveal.
| Animal or exposure | Bug | Gram stain | Buzzword | Disease |
|---|---|---|---|---|
| Wool, hair, hides | Bacillus anthracis | Gram-positive boxcar rods, spores | Painless black eschar; woolsorters disease | Anthrax |
| Rabbit, tick, deerfly | Francisella tularensis | Gram-negative coccobacillus, needs cysteine | Ulcer plus tender nodes; tiny dose | Tularemia |
| Flea off a rodent | Yersinia pestis | Gram-negative rod, safety-pin bipolar | Painful bubo | Plague |
| Unpasteurized dairy | Brucella | Gram-negative coccobacillus, intracellular | Undulant fever, night sweats | Brucellosis |
| Dog or cat bite | Pasteurella multocida | Gram-negative coccobacillus | Cellulitis with pus inside 24 hours | Bite cellulitis |
| Cat scratch | Bartonella henselae | Gram-negative rod, silver stain | Tender regional nodes | Cat-scratch disease |
| Water with animal urine | Leptospira interrogans | Hook-ended spirochete, darkfield | Calf myalgias, conjunctival suffusion, Weil | Leptospirosis |
| Livestock birth fluids | Coxiella burnetii | Tiny intracellular gram-negative | No vector, no rash; culture-negative endocarditis | Q fever |
| Fish, swine, butcher | Erysipelothrix rhusiopathiae | Gram-positive rod | Violaceous painful hand lesion | Erysipeloid |
Rounds: Board-Style Vignettes
Eight board-style vignettes. Shuffled, never-repeat, with full explanations for every choice. Cross out and highlight as you read, then walk the reasoning chain.