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. Stuck on youThe following video (liver) was taken during necropsy examination of a 2-year-old cow from eastern Texas. What is your diagnosis? Fasciola hepatica or liver flukes. These platyhelminths live in the bile ducts of ruminants and other mammalians. The adults produce large eggs that are excreted with feces. The eggs develop into a larva called miracidium inside the egg and then swims out to find a snail intermediate host. When fully developed the cercaria leaves the snail’s tissues and encysts as metacercaria in grass and pastures. After ingestion the young fluke penetrates the wall of the intestine and crosses the peritoneal space to the hepatic parenchyma, several weeks later the young flukes enter the bile ducts where they mature into adult parasites. The most common form of liver fluke diseases in cattle is chronic and rarely fatal, most animals develop anemia, decreased weight gain and submandibular edema. The acute form is more common in camelids and sheep in which the parasites can cause traumatic hepatitis by migration of the juvenile parasites. New Year's fun findingA 2-year-old female mule deer (Odocoileus hemionus) from western Oklahoma was submitted to the Oklahoma Animal Diseases Diagnostic Laboratory, for necropsy. During examination the following specimens were recovered from the cervical region.  Image 1: Adult nematode recovered from the cervical region of a deer Eleaphora shneideri female (F) and male (M), not associated to the cause of death in this case. (Image 2 and Image 3)
Image 2: Anterior end
Image 3: Posterior end of male nematode with cuticular thickenings (red arrow) and spicules (black arrow) These nematodes are common parasites of mule deer and deer in the US. Adults live in the carotid arteries or their branches; females measure an average of 10 cm and males 7 cm.
E. shneideri are transmitted by Tabanid flies considered cyclodevelopmental hosts. Infective larvae migrate to the leptomeningeal arteries where they develop into young adults and further migrate to the carotid or maxillary arteries where they become adults, releasing microfilariae (average 250 µm in length) into the bloodstream. (Images 4-6). In mule deer E. shneideri is often asymptomatic, in sheep it can cause dermatitis of the head as a reaction to the microfilariae in the skin, also referred as “sore head”. In other atypical hosts such as moose or elk they can develop clinical eleaphorosis, characterized by obstructed blood flow, thrombosis and endothelial damage. Image 4: Microfilaria Image 5: Anterior end of microfilaria Image 6: Posterior end of microfilaria Oinkmas: A piggy Christmas storyA 4-month-old pig was brought for necropsy examination at the Oklahoma Animal Disease Diagnostic Laboratory. The pig had recently died along with 3 other pigs (same age). All had a history of anorexia, low fever and diarrhea. The other 3 pigs had traces of blood on feces. During gross examination, gastritis, enterocolitis and numerous small parasites in the intestine were observed (not recovered). No parasite eggs, oocysts or cysts were recovered during fecal centrifugation from colon content. Histological examination revealed colitis, lymphoplasmacytic, histiocytic, neutrophilic and eosinophilic, with crypt abscess, chronic, moderate and intraepithelial and intraluminal nematodes (Figure 1). Thanks to Drs. Clare Brown and Daniel Barrantes-Murillo for contributing to this case.  Figure 1: A. Intraepithelial and intraluminal nematodes (arrowheads). Hematoxylin and eosin (HE). Bar = 400 mm. B. Transversal sections of intraluminal parasites. BB = bacillary band, C = cuticle, HY = hypodermis, SN = stichosome nucleus. HE. Bar = 60 mm. C. Transversal sections of intraluminal parasite. BB = bacillary band, CA = cuticular annulations, HY = hypodermis, S = stichosome. HE. Bar = 60 mm. D. Transversal sections of intraepithelial parasites. Pseudocoelom (asterisks) and polycytous intestine containing uninucleate epithelial intestinal cells (UI). HE. Bar = 60 mm. E. Transversal sections of intraluminal parasite. Hologenic ovary (O), polymyarian coelomyarian muscle (asterisk) and polycytous intestine containing uninucleate epithelial intestinal cells (UI). HE. Bar = 60 mm. F. The lamina propria is moderately expanded by the infiltration of moderate numbers of lymphocytes, plasma cells, histiocytes and fewer neutrophils and eosinophils, with crypt abscess (asterisk). HE. Bar = 60 mm. Trichuris suis, commonly known as whipworms are trichinellid parasites that live embedded within the epithelial cells of the large intestine, especially the cecum. Severe T. suis infections in young swine cause catarrhal enteritis with diarrhea, anorexia, and retardation of growth. Control of this parasite depends on separating swine from source of infective eggs, while treatment has been successful using Fenbendazole or Dichlorvos. |
