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Parasitic Diseases

Diagnosis and Treatment of Common Parasitic Diseases

Coccidiosis

Diagnosis:
Treatment (if clinical):
Sulfa, TMS, amprolium, toltrazuril (all OFF-label)
Leave subclinical infections untreated to allow development of immunity (it’s not zoonotic + will clear itself)
Control:
Remove feces daily
Keep floors clean and dry (steam and pressure washing beneficial)

Demodicosis

Diagnosis:
Treatment:

Fleas

Diagnosis:
Treatment:

Giardiasis

Diagnosis: Giardia ELISA SNAP, Fecal Flotation (ZnSO4)
Treatment (if clinical):
Fenbendazole 50mg/kg PO SID +/- Metronidazole 25mg/kg BID for 5 days
If treatment + bathing does not eliminate infection, extend for additional 10 days
Treat same household species with one course of therapy
Monitoring:
Recheck fecal flotation (ZnSO4) 24-48h after treatment if still clinical
Control:
Bathe on first and last day of treatment (especially muzzle, paws, perineum)
Remove feces immediately and dispose with municipal waste (cysts immediately infective)
Environmental areas (e.g., soil, grass, standing water) are difficult to decontaminate, but surfaces can be sanitized by steam-cleaning or use of commercially available disinfectants. Allow surfaces to dry thoroughly after cleaning.

Heartworm Disease

Diagnosis:
4Dx positive → confirm with repeat 4Dx + Microfilaria Filter Test
Treatment:
Day 1-28:
Apply heartworm preventative
If microfilaria detected, pre-treat with anti-histamine and glucocorticoid (if not already on prednisone) and monitor for 8 hours for anaphylaxis
Doxycycline 10 mg/kg BID for 4 weeks
Exercise restriction (the more pronounced the signs, the stricter the restriction)
If symptomatic:
Stabilize with supportive care
Prednisone 0.5 mg/kg BID first week, 0.5 mg/kg SID second week, 0.5 mg/kg every other day (EOD) for the third and fourth weeks
Day 30:
Apply heartworm preventative
Day 60:
Apply heartworm preventative
Melarsomine 2.5 mg/kg deep IM between L3-L4 (alternating sides)
Pretreat with diphenhydramine 2mg/kg IM and dexamethasone 0.125mg/kg IM
Prednisone 0.5 mg/kg BID first week, 0.5 mg/kg SID second week, 0.5 mg/kg EOD for the third and fourth weeks
Decrease activity even further (cage restriction, on leash when using yard)
Day 90:
Apply heartworm preventative
Melarsomine 2.5 mg/kg deep IM between L3-L4 (alternating sides)
Pretreat with diphenhydramine 2mg/kg IM and dexamethasone 0.125mg/kg IM
Day 91:
Melarsomine 2.5 mg/kg deep IM between L3-L4 (alternating sides)
Pretreat with diphenhydramine 2mg/kg IM and dexamethasone 0.125mg/kg IM
Prednisone 0.5 mg/kg BID first week, 0.5 mg/kg SID second week, 0.5 mg/kg EOD for the third and fourth weeks
Continue exercise restriction for 6 to 8 weeks following last melarsomine injections
Day 120:
Microfilaria Filter Test (1 month after last melarsomine injection)
If positive, treat with a microfilaricide and retest in 4 weeks
Continue heartworm preventatives based on risk assessment
Day 365:
Heartworm Antigen Test (9 months after last melarsomine injection)
If positive, re-treat with doxycycline followed by two doses of melarsomine 24 hours apart

Hookworm

Diagnosis: Centrifugal Fecal Flotation (Ancylostoma, Uncinaria)
Treatment:
Fenbendazole 50mg/kg PO q24h for 3 days, repeat in 14 days or,
Pyrantel 10mg/kg (<2.3kg) or 5mg/kg (>2.3kg) PO once, repeat in 14 days
Monitoring:
Repeat fecal flotation 2 weeks after last treatment
If still positive: different drug class (pyrantel or fenbendazole)
If still positive: macrocyclic lactone (milbemycin or moxidectin) once, repeat in 14 days
If still positive: use all 3 together (pyrantel, fenbendazole plus macrocyclic lactone)
Prevention: Every 2 weeks until 12 weeks old, then monthly until 6 months old

Lungworm

Diagnosis: Centrifugal Fecal Flotation (Capillaria and Paragonimus) AND Baermann (Aelurostrongylus)
Treatment: Fenbendazole 50mg/kg q24h for 10-14 days +/- antibiotic
Monitoring: Repeat fecal flotation 2 weeks after last treatment

Lyme Disease

Diagnosis:
PCR on tick
After an infected tick bite, 4Dx today AND in 6 weeks (seroconversion takes 3-5 weeks)
If positive: monitor for clinical signs for 6 months (5-10% develop disease) and proteinuria every 2-3 months in the meantime
If no baseline 4Dx, confirm active infection with Quant C6 test
Treatment (if clinical or proteinuric):
Doxycycline 10mg/kg PO q12-24h for 28 days

Roundworm

Diagnosis: Centrifugal Fecal Flotation (Toxocara, Toxascaris)
Treatment:
Fenbendazole 50mg/kg PO q24h for 3 days, repeat in 14 days or,
Pyrantel 10mg/kg (<2.3kg) or 5mg/kg (>2.3kg) PO once, repeat in 14 days
Monitoring:
Repeat fecal flotation 2-4 weeks after last treatment
Zoonosis: VLM and OLM
Prevention: Every 2 weeks until 12 weeks old, then monthly until 6 months old

Sarcoptic Mange

Diagnosis:
Treatment:

Tapeworm

Diagnosis:
Segments attached to perianal fur > fecal flotation
Typically no clinical signs or perianal pruritus
Treatment/Prevention:
Dipylidium caninum (dog/cat - fleas): Praziquantel, repeat in 2-4 months??? AND treat fleas
Taenia taeniaformis (cat - rodents): Praziquantel (eg. Milbemax) q24h for 2 consecutive days
Prevention for outdoor/cat that eats rodents: Praziquantel 1-4 times/year
Taenia pisiformis (dogs - rabbits):
Echinococcus multilocularis (dogs>cats - rodents):
Prevention for dog/cat that eats rodents + high-risk household: Praziquantel monthly
Reportable, zoonotic; MICROscopic

Trichomoniasis

Diagnosis: Tritrichomonas foetus PCR (more sensitive), Fecal Culture
Treatment (if clinical):
Ronidazole (human pharmacy or compounded) 30mg/kg PO q24h for 14 days
Elimination of clinical signs good but infection difficult in multicat households
Keep positive cats separate from other cats


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