Dog down on his luck
A fecal sample from a 2-year-old male dog with history of soft stools and vomiting was submitted to the parasitology diagnostic laboratory. The dog did not have history of deworming treatments. The following structures were observed after fecal centrifugation with sugar solution
Image 1: Specimen at 10x objective.
Image 2: Specimen at 40x objective.
Adelina sp., is an apicomplexan parasite of arthropods and oligochaetes that could be confused with Ancylostoma sp. eggs if not measured or if examined by inexperienced personnel. In this case it is a spurious parasite of the dog which is passing the oocysts, after ingesting arthropods or earthworms infected with the coccidian parasite.
The following images belong to an 8-month-old Quarter Horse colt from Kansas with a history of lethargy, inappetence, and abdominal pain that worsened over approximately 2 weeks. The colt died and a necropsy was performed. On gross examination, the large colon exhibited changes consistent with infarction. The cranial mesenteric artery contained a thrombus and on histopathology, the following was identified.
Image 1: 2X objective
Image 2: 10X objective
Strongylus vulgaris, is a member of the Strongylinae. The 4th and 5th larval stages migrate through the arterial system and cause verminous arteritis with marked intimal thickening and thrombus formation that can block arteries, causing infarction of intestinal walls commonly associated with anorexia, pyrexia, colic and death. Foals and yearlings are most commonly affected.
Case provided by Dr. Giselle Cino.
The following blood sample belongs to a cow from a beef herd in northeast Oklahoma with history of weight loss, icterus and hemoglobinuria. Eight of 140 animals died with no previous symptoms.
Image 1: Blood smear from a cow.
Anaplasma marginale is a tick transmitted pathogen which causes hemolytic anemia in cattle. In the US is mainly transmitted by the Dermacentor spp. ticks, however it can also be transmitted mechanically via biting flies, mosquitoes and contaminated fomites. Cattle infected with A. marginale show symptoms such as fever, abortion, icterus, weight loss and in some instances mortality. The morulae of A. marginale are found in erythrocytes of acutely infected cattle.
What is ailing the reindeer?
A blood sample from a 3.5-year-old female reindeer slightly underweight was submitted for a CBC and a modified Knott’s tests.
Image 1-3: Modified Knott's test.
Image 4: Microfilariae are 140-169 µM in length with a blunt rounded tail and a sheath closely pressed against the body of the microfilariae extends only a short distance beyond the head and tail which makes it difficult to see
Rumenfilaria andersoni, is a filarid nematode (Family Onchocercidae, subfamily Splendidofilariinae). It was firs described from moose (Alces alces) in Ontario, Canada and mistakenly to occur in subserosal veins of the rumen. Adult worms are 55-144 µM in length. In addition to moose, infections have also been reported in reindeer (Rangifer tarandus), white tail deer (Odocoileus virginianus) and roe deer (Capreolus capreolus). Infection in cervids have been reported in Alaska, Ontario and Finland. It may have been introduced into Finland in imported white-tailed deer from Minnesota donated by Finnish immigrants.
Case and photos provided by Dr. Gary Conboy.
Winter is coming....
In November 2020, these ticks were removed from a horse in Oklahoma and submitted to the parasitology lab for identification.
Images 1-3: Key features for identification.
These ticks are a brown variant of Dermacentor albipictus, or the winter tick, a one-host tick commonly found on horses and white-tailed deer in the southern region of North America. Formerly referred to as D. nigrolineatus, inornate winter ticks can be distinguished from Rhipicephalus spp. by the presence of a rectangular scutum. The ornate variant of D. albipictus more common in northern regions is often found feeding on moose, elk, and deer. In large numbers, D. albipictus contribute to poor condition and death in moose and elk. Winter ticks, as the name suggests, are most active in the fall and winter months, and have been implicated as vectors of Anaplasma marginale and Babesia duncani.
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