How do dogs become ill from a tick bite? - briefly
A feeding tick injects pathogens—bacteria, protozoa, or viruses—directly into the dog’s bloodstream, causing infections such as Lyme disease, ehrlichiosis, or anaplasmosis. These illnesses manifest as fever, lethargy, joint pain, and may lead to organ damage if not promptly treated.
How do dogs become ill from a tick bite? - in detail
Ticks attach to a dog’s skin, pierce the epidermis with their hypostome, and secrete saliva that contains anticoagulants, immunomodulators, and a range of pathogens. The saliva creates a localized feeding site that remains open for several days, allowing the tick to ingest blood while simultaneously injecting microorganisms.
Pathogens transmitted during feeding include:
- Bacterial agents such as Borrelia burgdorferi (Lyme disease) and Anaplasma phagocytophilum (granulocytic anaplasmosis). These bacteria enter the bloodstream through the feeding wound, multiply, and trigger systemic inflammation, joint pain, fever, and lethargy.
- Protozoal organisms like Babesia canis. After injection, the parasites invade red blood cells, causing hemolytic anemia, jaundice, and severe weakness.
- Rickettsial bacteria (Rickettsia rickettsii, causing Rocky Mountain spotted fever). These organisms spread via endothelial cells, leading to vasculitis, skin lesions, and high fever.
- Viral agents such as tick‑borne encephalitis virus (rare in dogs). The virus reaches the central nervous system, producing neurological signs including ataxia and seizures.
The progression from bite to illness follows a predictable pattern:
- Attachment and feeding – The tick inserts its mouthparts, creates a feeding capsule, and releases saliva.
- Pathogen inoculation – Microorganisms present in the tick’s salivary glands are deposited into the host’s tissue.
- Local response – Inflammation at the bite site may cause swelling, redness, and sometimes a small ulcer.
- Systemic dissemination – Pathogens enter the circulatory system, spread to target organs, and elicit immune reactions.
- Clinical manifestation – Symptoms appear after an incubation period that varies by agent (hours for some bacteria, weeks for others). Common signs include fever, loss of appetite, joint pain, anemia, and neurological deficits.
Preventive measures focus on eliminating ticks before they complete feeding, using regular acaricide treatments, and conducting thorough skin examinations after outdoor exposure. Early detection of a tick and prompt removal reduce the chance of pathogen transmission, as most agents require several hours of attachment to be transferred. Once infection is established, diagnostic testing (PCR, serology, blood smear) guides targeted antimicrobial or antiparasitic therapy.