Canine vector-borne disease in domestic dogs on Isla Santa Cruz, Galápagos.

Vector-borne diseases result in significant morbidity and mortality in domestic dogs in tropical and subtropical regions and also pose a potential threat to wildlife species and humans. Ehrlichia canis, the causative agent of canine monocytic ehrlichiosis (CME), has a high reported seroprevalence in dogs on Santa Cruz in the Galápagos Islands, Ecuador. Veterinary diagnostic and treatment resources are often scarce and clinical follow-up is lacking in the Galápagos. This study evaluated 58 dogs presenting to the Darwin Animal Doctors clinic in the city of Puerto Ayora on Santa Cruz Island during August of 2018. The seroprevalence of E. canis/Ehrlichia ewingii (48.3%), Anaplasma phagocytophilum/Anaplasma platys (12.1%), and Borrelia burgdorferi (0%), as well as the proportion of dogs actively infected with E. canis (12.1%) and E. ewingii (0%), are reported. Active infection was defined as the identification of antigen by PCR. Dogs with a packed cell volume (PCV) ≤ 30% had a 10-fold risk of active infection with E. canis compared to dogs with a PCV ≥ 31% (p = .0124). A PCV cutoff of 30% may be a useful screening tool for active E. canis infection in regions with high Ehrlichia seroprevalence, in the absence of other apparent causes of anemia. Dirofilaria immitis antigen was present in 6.9% of examined dogs, with the highest prevalence in the barrio Las Ninfas. PCR and Sanger sequencing were used to provide the first molecular identification of D. immitis in the Galápagos. This study updates the seropositivity and prevalence data of these canine vector-borne pathogens and highlights the need for continued surveillance in the region.

Evaluation of Parasite Egg and Cyst Recovery Using Devices Designed for Centrifugal or Stationary Flotation.

Two new devices (OT, ST), were recently introduced for the recovery of parasite eggs and cysts for microscopic examination. These devices, two stationary flotation devices, and a standard double-centrifugal sugar-flotation were compared using common flotation solutions and methods recommended by the manufacturers for the recovery of hookworm, ascaridoid, and whipworm eggs from companion animal fecal samples. Additionally, the recovery of Giardia cysts in the OT device using a zinc sulfate versus sodium nitrate solution was evaluated. Double-centrifugal sugar-flotation (1.30 specific gravity) was the most sensitive method for the recovery of the nematode eggs from feces of companion animals. Overall, centrifugation increased the recovery of eggs as compared with standing flotation methods, with the ST performing equivalently to the OT. Although these more recently introduced tests have good sensitivities for the nematodes tested, egg recovery was routinely markedly less than that achieved by standard double-centrifugal sugar-flotation, and false-negatives did occur. Still, the OT and ST generally have increased recoveries over the two standing flotation devices, and are significantly better than these for the recovery of ascaridoid and whipworm eggs from dog and cat samples. Zinc sulfate (1.18 specific gravity) is recommended for the recovery of Giardia cysts when using the OT device.