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TOday'S VeTerinary PracTice | September/October 2015 | tvpjournal.com ParaSiTOlOgy eXPerTiSe FrOM THe ncVP Peer reviewed 54 • This presentation described the genetic analysis and genetic diversity of Amblyomma species, specifically A maculatum, collected from several southern states. • Higher than expected sequence diversity was present in wild ticks, while colony ticks demonstrated homogeneity; it was not possible to distinguish between A triste and A maculatum with the sequences used. NEW & IMPROVED PARASITE DIAGNOSTIC TESTING STRATEGIES diagnosing parasites accurately is a key component of clinical parasitology. Several presentations focused on the creation and validation of novel assays to enhance identifcation of parasitic infections in practice. False Negative Antigen Tests in Dogs Infected with Heartworm (Diroflaria immitis): An Update & Case Series Jeff Gruntmeir, Researcher, Oklahoma State University • Heat treatment of serum prior to testing for heartworms has been shown to disrupt immune complexes, improving detection of heartworm antigen. • as many as 5% to 10% of dogs in animal shelters and more than 50% of dogs on slow kill protocols that initially test negative convert to positive after immune complexes are removed by heat treatment. 13,14 • This presentation shared data from a study in which 34 dogs suspected of being infected with heartworm initially tested negative for antigen. However, after heat treatment to disrupt immune complexes, antigen was detected in 22/34 (64.7%) of the samples; microfilariae were also present in whole blood from some, but not all, of the dogs with blocked antigen. • The importance of clinical judgment in making an accurate diagnosis was highlighted because, in these patients, veterinarians suspected heartworm infection, despite the negative antigen test, due to: » Presence of microflaria in whole blood (Figure 3) » History of poor or no preventive use » clinical signs consistent with heartworm infection (eg, coughing, murmur) » radiographic evidence of disease. Diagnosis of Feline Whipworm Infection in Southern Florida Jinming Geng, DVM, MS, PhD, IDEXX Laboratories, Inc • Feline whipworms, Trichuris campanula and Trichuris serrata, are considered common in much of the world but are rarely identified in north america, except in Florida and the caribbean islands. • data were presented from a study that identified Trichuris species in a high proportion of feral cats from Florida. Figure 3. Diroflaria immitis: Microflaria of D immitis from a modifed Knott's preparation on whole blood. The microflariae are approximately 295 to 325 mcm in length, and have a tapered head and straight tail. It is recommended that a modifed Knott's test be performed along with every heartworm antigen test. Courtesy National Center for Veterinary Parasitology Slow Kill Protocol Approach A description, the effcacy, and the problems associated with a slow kill protocol approach to heartworm treatment is addressed in Principles of treatment: Canine Heartworm Disease (March/April 2015 issue), available at tvpjournal.com . S l Figure 2. Amblyomma maculatum: A maculatum is known as the Gulf coast tick; this fgure shows a male and female of the species. Originally restricted to regions along the Gulf of Mexico, this tick is now found as far north as Kansas. A triste has similar variegated markings on its scutum, making morphologic differentiation of the 2 species diffcult. Courtesy National Center for Veterinary Parasitology