Bacterial Infections in Dogs and Cats: Symptoms and Medications

1 Leptospirosis

A zoonotic disease affecting many animals. Signs vary by age, immunity, and strain — usually jaundice, hemoglobinuria, short fever; pregnant dogs may abort. Incubation is about 5–15 days.

Acute: fever, tremors, muscle pain, then vomiting, rapid dehydration, fast breathing, erratic heartbeat, refused food; bleeding from gums, nose, or internally from damaged vessels. Later, deep depression, falling temperature, death. Subacute: fever, anorexia, vomiting, dehydration, increased thirst, congested mucous membranes, dry cough, conjunctivitis, rhinitis, and reduced urine from kidney failure. The hemorrhagic-jaundice strain’s hallmark is jaundice with possible liver failure (weight loss, ascites, hepatic encephalopathy); severe liver and kidney damage can cause uremia (bad breath, coma, ulcers). Treat with antibiotics plus supportive care; vaccinate to prevent, and use liver-support tablets in recovery.

2 Lyme Disease and E. coli Infection

Lyme disease, from Borrelia burgdorferi spread by ticks, is zoonotic. Dogs and cats show fever, lethargy, poor appetite, and some develop arthritis — swollen joints, sudden stiffness, lameness that shifts from leg to leg; eye and nerve signs appear, but kidney dysfunction (proteinuria, casts, blood, pus in urine) dominates. Prevent with tick control (a pet-safe topical avermectin kills ticks); joint supplements ease arthritis.

E. coli infection is also zoonotic, from Escherichia coli, causing sepsis and diarrhea. Incubation is 1–2 days or under 10 hours. It can kill fast: temperature spikes above 40°C, lethargy, yellow-white bubbly foul stools, then coma and death. Young pets show depression, fever, violent vomiting and diarrhea (yellow-green or gray, possibly bloody) and seizures. Treat supportively to stop diarrhea and dehydration; bismuth subcarbonate tablets curb gut bacteria.

3 Brucellosis and Pasteurellosis

Brucellosis causes genital inflammation and testicular swelling in dogs; pregnant dogs abort or become sterile. It is mostly hidden or just lymphadenitis, with up to half a year incubation. Before abortion, vaginal mucus is gray-green; afterward metritis blocks future pregnancy. Males show orchitis, epididymitis, prostatitis. Because the bacteria live inside cells, antibiotics work poorly — see a vet and add vitamins C and B1.

Pasteurellosis names many Pasteurella strains, usually secondary to distemper or panleukopenia, mostly in young dogs. Acute cases die in 3–5 days: high fever, dullness, refused food, more thirst, breathing trouble, red nasal discharge, cough, open-mouth breathing, red eyes with discharge, sometimes diarrhea. Eye drops ease the eye signs.

4 Staph and Salmonella Infections

Staph infection shows local pus, sometimes bacteremia or sepsis, mainly from Staphylococcus intermedius. Lesions carry pus; youngsters may get cellulitis and swollen nodes; it can also hit respiratory, reproductive, joint, and eye sites. Treatment is drainage; a pet skin gel fights bacteria and fungus and reduces swelling.

Salmonella is acute septicemic, mostly in young pets. Classic signs are gastroenteritis: fever, poor appetite, vomiting, belly pain, diarrhea from watery to mucous, sometimes gut bleeding (bloody, foul stools); after days, clear weight loss, severe dehydration, pale mucus, weakness, shock, jaundice.

Most pathogens are deadly, so focus on prevention: clean toileting areas daily (a pet enzymatic deodorizer kills odor and germs), disinfect belongings and environment during illness (a pet-safe glutaraldehyde-quat solution kills many bacteria and viruses), keep pets from strange animals when out, and stay current on vaccines and parasite control.