The nasal passengerA mule deer (Odocoileus hemionus) from Oklahoma was submitted for necropsy examination to the Oklahoma Animal Disease Diagnostic Laboratory (OADDL). Incidentally, larvae were recovered from the nasal passages (Images 1 and 2).
eCephenemyia sp. larva stage 3 (L3)
Bee-like female flies deposit larvae (L1) in the nasal passages of cervids. L1s are covered by a gelatinous fluid that protects them from desiccation and supports their adhesion. After a diapause they develop into L2 and move to the choanas and pharynx and larynx where they cluster. Mature L3s move to the nostrils and when the host sneezes or coughs they drop to the ground to pupate and emerge as adults a few weeks later according to the environmental temperature and conditions. Clinical signs are associated with the narrowing of the upper airways and nasal mucosa irritation caused by the larvae. Secondary infections can occur. Observed clinical signs are coughing, sinusitis, nasal discharge and in some instances open mouth breathing. Heavy infestations can cause weakness and exercise intolerance. Diagnosis is by location on host and general morphology. L3s average 1 to 1.2 inches in length, they have V shape antenna lobes (image 3, arrows) and C shape posterior spiracles (image 2). 
Image 3: Arrows showing V shape antenna lobes. Trouble in the rumenA 2-year-old cow from central Oklahoma was submitted for necropsy examination to the Oklahoma Animal Disease Diagnostic Laboratory (OADDL). Incidentally, the following specimens (~ 1 cm long) were collected from the rumen (Image 1).  Image 1: Specimens collected from the rumen, (~ 1 cm long). Cotylophoron sp., originally described by Fishoeder in 1901, belongs to the family Paramphistomidae with similar characteristics to Paramphistomum sp. In 1910, Stiles and Goldberger distinguished these two genera by a single characteristic, the presence of a genital sucker in Cotylophoron sp. Both have an oral sucker and a posterior sucker (Images 2 and 3). Paramphistomids are parasites of ruminants requiring a snail as first intermediate host to complete their life cycle. In the USA, they have been associated with diarrhea, dullness, and loss of body condition in buffalo and cattle in southern USA. Diagnosis in live animals depends on detection of eggs by fecal sedimentation, when adults are developed.
Image 2: Oral sucker. Image 3: Posterior sucker. Sheep under siegeA fecal sample from a one-year-old goat from central Oklahoma was submitted to the Parasitology Diagnostic Laboratory (OADDL) to perform a fecal egg count (FEC) and a fecal culture for parasite identification. A history of intermittent watery diarrhea and a FAMACHA score of 3 was provided in the anamnesis. The McMaster FEC result was 1,650 EPG, and the majority of larvae recovered after 9 days of fecal culture are shown in image 1 (~580 µm length).  Image 1: Larvae recovered from culture after 9 days, (~580 µm length). Chabertia ovina is a parasite that infects the colon of ruminants but mostly reported in sheep. The adults have a large buccal capsule without teeth. The adults can cause local bleeding and diarrhea leading to weight loss and anemia.
C. ovina larvae can be morphologically differentiated from other parasite larvae by the sheathed tail length, number of intestinal cells, and total length. C. ovina larvae measure <750 µm, the sheathed tail is ≤150 µm (image 2, black arrow) and the number of cells ranges from 28-32 rectangular cells (image 3, black arrow). This case seems unusual as the majority of caprine fecal larval cultures are typically overrepresented by Haemonchus contortus larvae. Image 2: Sheathed tail is ≤150 µm (black arrow). Image 3: Intestinal cells ranges from 28-32 rectangular cells (black arrow). 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. |
