Eucoleus boehmi

Synopsis

CAPC Recommends

• Finely pitted, bipolar eggs are found in the feces and nasal discharge of infected dogs.
• There are no known intermediate hosts; transmission is suggested to be through direct contact between hosts.
• Nasal capillarids may be considered with upper respiratory infections not responding to antibiotics and can be verified by recovering of eggs by flotation.

Species

Canine

Eucoleus boehmi (syn.Capillaria boehmi) – canine nasal capillarid.

Eucoleus boehmi is the nasal capillarid of the dog. The adult worms live in the nasal cavity and paranasal sinues of dogs and related canids. It was originally described from the frontal sinus of a fox.

Overview of the Life Cycle

• The adults live threaded through the mucosa of the nasal sinuses. The life cycle has not been worked out in detail but is believed to be direct.

Stages

• Adults are small and are threaded through the mucosa of the sinuses in which they live. They are white nematodes, 22-43mm long.
• The eggs of Eucoleus boehmi may be found in nasal discharges or feces and are 54-60 x 30-35 μm. The surface of the egg of is pitted.
• The egg is passed in a partial stage of embryonation, and the developing morula in the egg often appears square or rectangular.
• Embryos within the eggs are retracted from the shell and do not fill the entire egg.

Disease

• Light infections are usually inapparent.
• Most cases are asymptomatic
• Chronic rhinitis may be present in heavy infections with infected dogs having chronic serous nasal discharge and reverse sneezing. If secondary infection occurs, the discharge can become purulent.
• Rare intracranial migration of eggs has been reported, and associated with seizures and meningoencephalitis.

Prevalence

• Not well known, sporadic reports in Europe, North and South America.
• One study found 0.4% of 6458 canine fecal samples in the US were positive for Eucoleus spp. (Blagburn et al., 1996).
• May be more prevalent in hunting dogs with access to wild canids.

Host Associations – Transmission between Hosts

• This is a parasite of wild and domestic canids.
• Transmission is suggested as fecal-oral; no known intermediate hosts have been documented.

Prepatent Period – Environmental Factors

• Unknown

Site of Infection – Pathogenesis

• The adult worms are threaded through the epithelial lining of nasal turbinates and sinusus.
• Inflammation of the epithelia of the sinuses due to the presence of the worms and eggs.

Diagnosis

• Diagnosis is made by identification of the eggs in nasal discharge or feces.
• The eggs in the feces must be differentiated from those of Trichuris vulpis(which are larger and have a smooth shell), Eucoleus aerophilus (that contain a single cell when passed and have anastomosing ridges on the outer shell), and Personema plica and Pearsonema felis cati that can be in feces contaminated with urine.

Treatment

• Ivermectin and fenbendazole have both been used effectively for treatment.
• Milbemycin oxyme (by mouth) 2.0mg/kg has been used effectively in 2 dogs, with no eggs recovered in feces at a 6 month post-treatment exam (Cervone et al., 2017).
• Topical imidacloprid 10%/moxidectin 2.5% has been used effectively with resolution of clinical signs and no eggs recovered in feces 28 days post-treatment (Veronesi et al., 2017).

Control and Prevention

• Routine preventatives are probably not protective.

Public Health Considerations

• No human health hazard appears to be associated with Eucoleus boehmi.

Selected References

• Blagburn BL, Lindsay DS, Vaughn JL, Rippey NS, Wright JC, Lynn RC, Kelch WJ, Ritchie GC, Hepler DI. Prevalence of canine parasites based on fecal flotation. Compend Contin Educ Pract Vet. 1996; 18:483-509.
• Cervone M, Messina N, Perruci S. Nasal capillariosis due to Eucoleus boehmi in two naturally infected dogs. Revue Vétérinaire Clinique. 2017; 52: 41-45.
• Clark AC, Loípez FR, Levine JM, Cooper JJ, Craig TM, Voges AK, Johnson MC, Porter BF. Intracranial migration of Eucoleus(Capillaria) boehmi in a dog. J Small Anim Pract. 2013; 39:99-103.
• Conboy G. Helminth parasites of the canine and feline respiratory tract. Vet Clin Small Anim. 2009; 39: 1109-1126.
• Veronesi F, Di Cesare A, Braun G, Günther L, Morganti G, Rueca F, Petry G, Schaper R, Traversa D. Evaluation of the clinical efficacy and safety of a spot-on combination of imidacloprid 10%/moxidectin 2.5% (Advocate®, Advantage®Multi) in comparison to an untreated control group in the treatment of Capillaria boehmi in naturally infected dogs. Parasitol. Res. 2017; 116:S65-S74.