Canine Tick-Borne Disease Reference (Lyme, Anaplasma, Ehrlichia, RMSF, Babesia)
Reference for the most common canine tick-borne diseases - vectors, signs, diagnostics, and first-line treatment.
Lyme disease (Borrelia burgdorferi)
| Aspect | Details |
|---|---|
| Vector / region | Ixodes ticks; NE & upper MW US, EU |
| Clinical signs | Shifting lameness, fever, lymphadenopathy; protein-losing nephropathy ("Lyme nephritis") |
| Diagnosis | SNAP 4Dx (C6 antibody); confirm with quantitative C6 + UPC ratio |
| Treatment | Doxycycline 10 mg/kg PO q24h × 30 days |
Anaplasmosis (A. phagocytophilum)
| Aspect | Details |
|---|---|
| Vector / region | Ixodes ticks; NE & upper MW US, EU |
| Clinical signs | Fever, lethargy, polyarthritis, thrombocytopenia |
| Diagnosis | SNAP 4Dx; morulae in granulocytes on smear |
| Treatment | Doxycycline 10 mg/kg PO q24h × 28 days |
Ehrlichiosis (E. canis)
| Aspect | Details |
|---|---|
| Vector / region | Rhipicephalus sanguineus (brown dog tick); S US, tropics |
| Clinical signs | Acute: fever, thrombocytopenia. Chronic: pancytopenia, bleeding, ocular lesions |
| Diagnosis | SNAP 4Dx; IFA titer; PCR |
| Treatment | Doxycycline 10 mg/kg PO q24h × 28 days (acute); longer for chronic |
Rocky Mountain Spotted Fever (R. rickettsii)
| Aspect | Details |
|---|---|
| Vector / region | Dermacentor & Rhipicephalus ticks; Americas |
| Clinical signs | High fever, vasculitis, petechiae, neurological signs |
| Diagnosis | Clinical signs + paired IFA titers (4× rise) |
| Treatment | Doxycycline 5–10 mg/kg PO/IV q12h × 14 days. START EMPIRICALLY if suspected. |
Babesiosis (Babesia spp.)
| Aspect | Details |
|---|---|
| Vector / region | Rhipicephalus; transfusion; bite wounds (B. gibsoni in Pit Bulls) |
| Clinical signs | Haemolytic anaemia, thrombocytopenia, jaundice |
| Diagnosis | Blood smear (intra-erythrocytic organisms); PCR for species |
| Treatment | Imidocarb (B. canis); atovaquone + azithromycin (B. gibsoni) |
A positive SNAP 4Dx indicates exposure, not necessarily active disease. Doxycycline is empirical first-line for most tick-borne diseases - treat suspect cases promptly, confirm later.
Frequently asked questions
A positive SNAP 4Dx means active disease?
No - it indicates exposure. A positive Lyme C6 in an asymptomatic dog in an endemic area is common and doesn't require treatment unless there's proteinuria (UPC > 0.5) or clinical signs. Quantitative C6 and UPC ratio help triage.
Is doxycycline the right empirical choice for tick-borne disease?
Yes for Rickettsia, Ehrlichia, Anaplasma, Lyme - any tetracycline works but doxycycline is the standard at 10 mg/kg PO q24h for 28-30 days. Babesia is the exception - needs imidocarb or atovaquone-azithromycin.
When should I treat empirically before test results?
Rocky Mountain Spotted Fever - mortality climbs without prompt doxycycline. Suspected anaplasmosis with fever + thrombocytopenia in endemic area. Suspected ehrlichiosis with pancytopenia. Don't wait for IFA / PCR results in any of these.