Infectious Diseases in Dogs: Overview, Pathogens, and Prevention
Infectious Diseases in Dogs: Overview, Pathogens, and Prevention
What are infectious diseases in dogs?
Infectious diseases in dogs are caused by pathogens—viruses, bacteria, fungi, or parasites—that enter the body, multiply, and trigger symptoms of illness. They vary considerably in terms of transmission, severity, treatability, and prevention options.
Important for dog owners: Some infectious diseases can be prevented through vaccination (parvovirus, distemper, leptospirosis). Others are zoonotic—transmissible to humans—and require special hygiene measures (leptospirosis, Toxocara, Campylobacter). Dogs that travel are at increased risk of contracting pathogens that are rare in Germany.
Background + Scientific Context
Greene (2012, *Infectious Diseases of the Dog and Cat*, Elsevier) provides a comprehensive overview of the spectrum of infectious diseases in dogs: Viral diseases (parvovirus, distemper, adenovirus, coronavirus) can be prevented by vaccination and are often fatal if left untreated. Bacterial diseases (leptospirosis, Bordetella, Brucella canis) are partly zoonotic and require antibiotic therapy. Fungal diseases (Aspergillus, Malassezia, dermatophytes) are usually secondary and require long-term therapy. Parasitic diseases (Toxocara, Giardia, Leishmania, Ehrlichia) are transmitted, depending on the pathogen, by vectors, via the fecal-oral route, or through direct contact.
Sykes (2013, *Canine and Feline Infectious Diseases*, Elsevier) analyzes travel-associated infectious diseases: Dogs traveling from the Mediterranean region bring back pathogens that are naturally not endemic to Germany—*Leishmania infantum*, *Ehrlichia canis*, and *Babesia vogeli*. These diseases are transmitted by sand flies and ticks, respectively. Laboratories with specialized travel blood profiles can detect infections early on after travel.
Müller and Schaper (2022, Kleintierpraxis, PubMed 35368000) published a study on parasite prevention in dogs in Germany: Regular deworming and ectoparasite prevention remain the most important preventive measures against parasitic infectious diseases. Resistance is developing in certain parasites (Toxocara); individual risk assessment is prioritized over blanket treatment intervals.
Vitomalia-Position
Infectious diseases in dogs can be managed through vaccination, parasite prevention, hygiene, and early veterinary detection. Dogs that have traveled and shelter dogs have a higher risk of carrying pathogens, which must be taken into account during the initial examination. Zoonotic diseases require owner education—especially when there are children or immunocompromised individuals in the household.
When do infectious diseases become a concern?
- Puppies and young dogs: particularly susceptible to parvovirus and distemper
- After staying at an animal shelter, boarding facility, or dog show: risk of kennel cough, parvovirus
- When traveling to endemic areas (Southern Europe, Eastern Europe): Leishmania, Ehrlichia, Babesia
- In cases of unexplained fever, vomiting, diarrhea, or jaundice: Leptospirosis as a differential diagnosis
- For dogs that come into regular contact with water: increased risk of leptospirosis
- If a fecal test is positive for zoonotic pathogens (Toxocara, Giardia): Hygiene measures
Practical application
Major Infectious Diseases in Dogs — An Overview:
| pathogen | Illness | Transmission | Vaccination |
|---|---|---|---|
| Parvovirus CPV-2 | Parvovirus | Fecal-oral, environmental | And (Core) |
| CDV | Canine Distemper | Aerosol, Contact | And (Core) |
| Leptospira spp. | Leptospirosis | Water, rodents | And (Non-Core) |
| Bordetella/CPIV | Kennel Cough | Aerosol | And (Non-Core) |
| Leishmania infantum | Leishmaniasis | sand flies | Yes (Travel) |
| Toxocara canis | Toxocariasis | Fecal-oral | No (deworming) |
Preventive measures: 1. Follow the WSAVA/StIKo Vet vaccination schedule 2. Regular fecal examinations (1–2 times a year) 3. Protection against ectoparasites (ticks, fleas, sand flies when traveling) 4. Hygiene after contact with animals, especially for children
Common Mistakes & Myths
- “My dog doesn’t come into contact with other dogs—he doesn’t need a vaccine.” Parvovirus can survive in the environment for months; transmission is possible via shoes and contaminated surfaces without direct contact.
- "Travel-related illnesses do not occur in Germany." Imported pathogens (Leishmania, Ehrlichia) are becoming increasingly established in parts of Germany; tick vectors are expanding their range due to climate change.
- “A single deworming treatment is sufficient.” Toxocara and Giardia can cause reinfection; regular fecal examinations and deworming as needed are more effective in the long run than routine treatment.
Current State of Research (2026)
The travel habits of European dog owners have altered the pathogen profile in German veterinary practices—diagnoses of Leishmania are on the rise, even though sand flies are not yet established in Germany. Climate-driven vector expansion (Hyalomma ticks) is bringing Tropenia and Crimean-Congo hemorrhagic fever (a risk organism) into the veterinary spotlight. Metagenomic diagnostic methods are increasingly enabling the detection of rare pathogens without the need for culture.
Frequently Asked Questions
Which infectious dog diseases can be transmitted to humans?
Major zoonotic diseases: Leptospirosis (urine from infected dogs), Toxocara canis (larvae in dog feces), Campylobacter (intestinal infection), dermatophytes (skin fungus), Brucella canis (brucellosis). Risk particularly for children and immunocompromised individuals. Wash hands after contact with dogs, do not let dogs lick your face, dispose of dog feces immediately.
How can I tell if my dog has an infectious disease?
General symptoms: fever, lethargy, loss of appetite, vomiting, diarrhea. Pathogen-specific symptoms: bloody stool (parvovirus), neurological symptoms (distemper), jaundice (leptospirosis), swollen lymph nodes (leishmaniasis). If you suspect an infection, see a veterinarian immediately—many infectious diseases can rapidly worsen without treatment.
How can I protect my dog from infectious diseases while traveling?
Before the trip: Have a travel blood profile done; check vaccination status (rabies, Leishmania vaccine where indicated). Use ectoparasite protection against sand flies and ticks. During the trip: Avoid uncontrolled contact with stray animals; do not drink from standing water. After the trip: Have a travel blood profile done 4–6 weeks after returning (take incubation periods into account).
Related terms
- Vaccinations for Dogs
- Canine Parvovirus
- Leptospirosis in Dogs
- Parasites in Dogs
- Motion sickness in dogs
Sources & Further Reading
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Greene, C. E. (2012). Infectious Diseases of the Dog and Cat (4th ed.). Elsevier. ISBN 9781416061304.
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Sykes, J. E. (2013). Canine and Feline Infectious Diseases. Elsevier. ISBN 9781437707953.
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Müller, R. S., & Schaper, R. (2022). Parasite prevention in dogs in Germany. Kleintierpraxis, 67(3), 146–168. https://pubmed.ncbi.nlm.nih.gov/35368000/