Restless ruminantThe following flies were found on an open wound from a cow in southcentral Oklahoma. No larvae were observed by the attending veterinarian.  Cochliomyia macellaria, the secondary screwworm. These flies belong to the Calliphoridae family within the Dipetera order. Adult flies live up to 6 weeks and lay 50 to 200 eggs which, depending on air temperature, can hatch in a day. Larvae feed on carrion and upon maturity they move to a pupation area usually in the topsoil. Pupation lasts 7 to 10 days.
Clinical relevance: Fly larvae can infest the tissues of living animals causing myasis and potentially transmiting bacteria and viruses. Additionally, these flies could be morphologically confused with Cochliomyia hominivorax, the primary screwworm, which is currently absent in the USA. Adults can be differentiated by the length of the thoracic stripes where in C. macellaria they are the same length while in C. homnivorax the middle stripe is shorter than the outer stripes (white arrows on image). 
What the shell hidesAn adult male red-eared slider was presented at the Oklahoma Animal Disease Diagnostic Laboratory for a necropsy exam. The turtle had caudal carapacial fractures, poor body condition and multiple parasites in the small intestine. Adult parasites measured approximately 2.0 - 2.5 cm in length (Image 1). The anterior end shows a proboscis with hooks (Images 2-4). The eggs recovered by fecal sedimentation measured approximately 25-30 µm x 15µm in length (Image 5). Thank you to Dr. Daniel Barrantes Murillo (Oklahoma State University, OSU), Rachel Smith (OSU), Dr. Kathryn Duncan (OSU) and Dr. Ryan Koch (University of Pennsylvania) for their contribution and assistance with this case.  Image 1: Adult found at necropsy. Images 2-4: Anterior end.  Image 5: Egg recovered by fecal sedimentation measured approximately 25-30 µm x 15µm in length Neochinorhynchus pseudemydis Acantocephalan parasites belonging to the genus Neochinorhynchus infect turtles and fresh and brackish water fish. Currently there are 10 Neochinorhynchus spp. described from freshwater turtle definitive hosts, with ostracods acting as the intermediate hosts or when known from some species, other vertebrate and invertebrate paratenic hosts. Species identification can be achieved by egg morphology. Pathogenicity of acanthocephalan parasites varies according to number of parasites and depth of penetration into the host tissue. Whiskers' unexpected battleA 12-year-old shorthaired domestic cat was presented to a veterinary clinic with a history of chronic cough and anemia. A fecal sample was submitted to the Oklahoma Animal Disease Diagnostic Laboratory for a Baermann test. No larvae were recovered on Baermann, but a subsequent double fecal centrifugal flotation was performed with the following findings (Image 1).  Image 1: Eggs recovered from double fecal centrifugal flotation. Ancylostoma sp. Domestic cats in the USA can be infected with Ancylostoma tubaeforme and Ancylostoma braziliense. Infection occurs by ingestion of infective larvae from the environment and through skin penetration. Because transmammary transmission does not occur in cats, infection with this parasite is less common than in dogs. Young cats can develop weakness, listlessness, poor weight gain and anemia; however, infected cats rarely develop severe clinical disease. Infection with Ancylostoma sp. is rarely detected in adult cats, in the case reported here, another etiological agent could be present, causing immunosuppression. Ancylostoma tubaeforme adults live in the small intestine, and like A. caninum of dogs, these parasites have three pairs of sharp teeth in the ventral stoma, while A. braziliense only has one pair. Crypto-currentThe following is a combined sample using 2 grams of feces from a 2-week-old calf with diarrhea and 2 grams of feces from a 11-month-old heifer with normal feces, both from central Oklahoma. The purpose of this image is to compare oocysts’ size and shape from 2 different Cryptosporidium species. The combined fecal sample was centrifuged with Sheather’s sugar solution.  Image 1: Oocysts pointed by black arrows. 
Image 2: Cryptosporidium parvum (Cp) and Cryptosporidium andersoni (Ca)
C. parvum was first described by Tyzzer in 1912, while C. andersoni was first reported by Upton and Current in 1985 as C. muris-like but later named C. andersoni by Lindsay et al., 2005. While transmission of both species is by ingestion of the immediately infected oocysts discharged in feces, oocysts size and shape, location in the host and clinical signs differ (see table below).
The infective oocysts can remain viable for months unless exposed to extremes of temperature or desiccation, therefore isolation of the infected animals is important. Unfortunately in the USA, no approved or effective treatment exist in cattle. Seeing doubleA neurologic raccoon was admitted into care to a rehabilitation center in Oklahoma and opportunistically sampled for fecal parasite assessment. The following was observed during fecal centrifugation with Sheather’s solution (Image 1). Note A and B are similar but slightly different. Thank you to Will Funk at WildCare Oklahoma and Dr. Kathryn Duncan for the case contribution.  Image 1: Fecal from raccoon. Note A and B are similar but slightly different. Eucoleus (=Capillaria) procyonis (A) and Aonchotheca putorii (B), both commonly known as capillarids. To date, four species belonging to the Capillariidae family have been reported in raccoons. Pearsonema plica from urinary system, Eucoleus aerophilus from respiratory tract, Aoncotheca putorii from the gastrointestinal tract, and Eucoleus (=Capillaria) procyonis from esophageal mucosa and tongue epithelium. Though they look similar at first, the two parasites above are identified by closely examining the external texture of their ova. Pearsonema plica is typically found in urine samples and has a thick, globular pattern of rides on their eggshell. The eggshell of E. aerophilus has a network of interconnecting ridges. Aonchotheca putorii demonstrates highly defined, deep longitudinal ridges on the eggshell. Eucoleus (=Capillaria) procyonis eggshell surface has a pitted appearance. Reindeer on a strollA blood sample from a reindeer in Iowa was submitted to a parasitology laboratory in Oklahoma for identification of a suspected hemoparasite (Image 1_arrow). The reindeer had a history of travel between Minnesota, Wisconsin, and Iowa. CBC analysis revealed hematocrit of 10%. Thanks to Dr. Claire B. Andreasen for providing the sample and Dr. Kathryn Duncan, Oklahoma State University, for sharing this case.  Image 1: Suspected hemoparasite on blood smear Theileria cervi. This protozoan parasite can infect cervids through the bite of Amblyomma americanum, the lone star tick. To date, few reports exist documenting disease from this intracellular parasite and it is generally considered nonpathogenic. Cases when animals were reported to have clinical signs, they were either malnourished or co-infected with other pathogens. The identification of this parasite was molecularly confirmed by PCR. |
