This dog and man at first were friends;
But when a pique began,
The dog, to gain some private ends,
Went mad, and bit the man. …
But soon a wonder came to light
That showed the rogues they lied,—
The man recovered of the bite,
The dog it was that died!
Education and career
Born in Ireland in 1728, Oliver Goldsmith was the son of a Protestant clergyman. In childhood, he suffered from smallpox and was left with his face permanently scarred. In 1749, he graduated from Trinity College, Dublin, then went to Edinburgh in 1752 to study medicine, joined the Students’ Medical Society, and was greatly impressed by the faculty’s teaching. Writing enthusiastically to his uncle Thomas Contarine, he said physicians needed to have a broad education because diseases presented themselves in so many diverse ways. After some time in Edinburgh, he transferred to the University of Leiden. He did not find this change to his liking, because he thought the professors were lazy and more interested in collecting their fees rather than teaching or giving lectures. He was particularly critical of the rigid, traditional lecturing style of continental university teachers, who, rather than fostering critical thinking, simply read outdated Latin texts to passive audiences. This stood in sharp contrast to Edinburgh, which had become a dynamic center of medical science.
After traveling extensively across continental Europe, Goldsmith arrived in London in 1756. At first, he worked as an apothecary assistant, but lacking a reliable income he turned to teaching and writing. In 1774, he compiled the eight-volume An History of the Earth and Animated Nature, drawing on naturalists such as Buffon and Linnaeus. He eventually gained fame from his novel The Vicar of Wakefield (1766), the play She Stoops to Conquer (1773), the poem “The Deserted Village” (1770), and the essay collection The Citizen of the World (1762). His career ended in March 1774, when, against medical advice, he treated himself with James’s fever powder, a blend of calcium phosphate and oxide of antimony intended to act as a heavy sweating agent to “break fevers,” which made him grow weaker, and he died on April 4.
Earlier, in 1766, Oliver Goldsmith had written the poem “Elegy on the Death of a Mad Dog” and included it in The Vicar of Wakefield rather than publish it separately. The novel portrays the naive country clergyman Dr. Charles Primrose and his family as they endure a relentless series of misfortunes, only for everything to be miraculously set right at the end. Rather than publish it separately, Goldsmith integrated this lighthearted, satirical poem into the novel’s narrative by having it recited at a social gathering. The poem describes a “good man” who adopts a dog, a “mongrel, puppy, whelp, and hound, and cur of low degree.” The dog loses his wits and bites “so good a man.” Surprisingly, the dog dies, an outcome unlikely in most encounters between dog and man.
Human diseases from dogs
Rabies is the most deadly of such diseases and is almost always fatal unless treated immediately after exposure. The virus attacks the nervous system and is usually transmitted through bites, although infected saliva can also enter the body through broken skin, eyes, or the mouth. Dogs cause about 99 percent of human rabies worldwide, with the greatest burden in Asia and Africa. In the United States, dog rabies is rare because vaccination and control programs have reduced it; most animal cases now occur in wildlife, especially in bats, raccoons, skunks, and foxes. Any potential exposure to a rabid animal requires urgent medical assessment.
Bacteria are now a more common cause of dog-to-human infection, especially by Pasteurella and Capnocytophaga canimorsus, which are commonly found in dogs’ mouths. Capnocytophaga warrants particular attention because it can progress to sepsis quite rapidly, especially in people lacking a functioning spleen, alcoholics, or those with otherwise impaired immune systems. Transmission occurs through bites or when a dog licks an open wound. All bites and contact between dog saliva and broken skin need to be taken seriously, as do infections caused by human intestinal bacteria such as Campylobacter, which dogs can carry without showing signs of illness, especially puppies acquired from pet stores. Another bacterial infection, leptospirosis, can also be spread through contact with infected dogs or rodents, or indirectly by contaminated water or soil. Vaccines are available for dogs, although they do not protect against every strain.
Dogs also harbor several parasitic worms that can cause disease in humans. Toxocara canis, the dog roundworm, lives in the small intestine of dogs. Children who play in contaminated grounds, especially if they eat dirt, are particularly vulnerable. Larvae can migrate through human tissues and may cause fever, cough, enlarged liver, rashes, and abdominal pain. If they enter an eye, they can damage the retina and impair vision. Many infections, however, produce no symptoms.
Another parasitic worm, the dog hookworm (Ancylostoma caninum), is a tiny, blood-sucking parasite that uses its hook-like mouthparts to anchor itself in the intestinal lining, where it feeds on the host’s blood and can cause severe anemia. Humans cannot catch a hookworm directly by petting or touching a dog; the parasites must first incubate in the environment. Hookworms can cause cutaneous larva migrans, sometimes called “creeping eruption.” Their larvae develop in soil or sand contaminated by animal feces and penetrate exposed skin, such as when people walk barefoot. They produce intensely itchy, winding red tracks beneath the skin. Most infections remain confined to the skin, although some species can involve deeper tissues.
Dipylidium caninum, the flea tapeworm, occasionally infects humans, particularly young children. Infection occurs when a person swallows an infected flea; a flea bite does not transmit the worm. In humans, the infection is usually mild or even asymptomatic, and may only be first recognized when small, rice-like tapeworm segments appear in the stool. Effective treatment is available, and flea control is essential to prevent reinfection.
A more serious parasitic disease is hydatid disease (echinococcosis). Dogs carrying certain Echinococcus tapeworms shed eggs in their feces, and people who accidentally swallow these eggs may develop slowly growing cysts, often in the liver or lungs. People can become infected through contact with contaminated dogs, food, water, or soil. Risk varies considerably by region and is especially high where the parasite circulates between dogs and livestock. People most often acquire this infection by swallowing microscopic eggs. In the past, some infections were so common that medical students had to buy the textbooks their professors wrote on the subject.
Despite its name, ringworm is not a worm but a fungal infection, the same species in dogs and humans, caused by organisms that feed on the keratin in their hair and skin. Dogs can pass their infection to humans, who develop an itchy, often circular rash with clearer skin in the middle. Contaminated bedding and other objects also spread ringworm. Treating the animal and cleaning its surroundings are therefore important, alongside treating the affected person. Treating ringworm in animals requires a combination of oral medication, topical therapy, and thorough environmental decontamination. In general, avoiding infection from animals depends largely on maintaining normally recommended healthy habits: regular veterinary care, appropriate vaccination and parasite control, prompt fecal collection, and handwashing after handling dogs or their supplies. Children need supervision even around familiar animals. Bite wounds need to be washed immediately with soap and running water; deep wounds, worsening redness, and possible rabies exposures require prompt medical attention.