Lecture 15/16 4/11/24 Flashcards
What are the characteristics of Toxoplasma gondii?
-DH is felids only
-IH/PH is mammals (including cats, humans, marine mammals) and birds
-reservoir/transport includes filter feeders, earthworms, fish
-zoonotic
What are the characteristics of Neospora caninum?
-DH is canids only
-IH includes cattle, cat, dog, sheep, goat, deer, marine mammals
-not zoonotic
What are the life stages of Toxoplasma/Neospora?
-oocysts
-tachyzoites
-bradyzoites
Which life cycle stage of Toxoplasma/Neospora is disease-causing?
tachyzoites
What are the characteristics of bradyzoites?
-dormant
-stay in the animal
-not treatable
What is the optimal life cycle for Toxoplasma?
want the cat DH to prey on an animal with bradyzoites in the tissue
Which Toxoplasma life stages have the potential to be infectious to the cat?
-oocyst
-tachyzoite
-bradyzoite
Why does Toxoplasma want to be ingested by the cat in the bradyzoite stage?
-quicker turnover to tachyzoite production
-more likely to shed a higher number of oocysts
When is it possible for transplacental or lactogenic transmission of Toxoplasma to occur?
-mother cat is experiencing first infection
-tachyzoite acute phase must occur during pregnancy or lactation
Which factors affect the pathology of Toxoplasma?
-location of tachyzoites/which cells rupture
-genotype virulence
-host age and genetics
-co-infections
-immunosuppression/recrudescence
What clinical signs are seen in normal cats with Toxoplasma?
-often no signs
-may have diarrhea if shedding
What clinical signs are seen in congenitally infected kittens and immunocompromised cats with Toxoplasma?
-fever
-resp. distress
-jaundice
-ocular disease
-seizures
What clinical signs are seen in dogs when they serve as an IH/PH for Toxoplasma?
-neurologic signs
-myositis
-GI signs
-ocular disease
-cardiac signs
-lymphadenopathy
What clinical signs are seen in ruminants/swine when they serve as an IH/PH for Toxoplasma?
goats: abortions; incomplete immunity with possible recurring abortion
sheep: abortions; complete immunity with no recurring abortions
cattle: likely immune, abortions are uncommon
-swine: possible abortion, neonatal piglet disease, stillbirth
How does Toxoplasma infection differ between old and new world monkeys?
Old: natural infections are rare
New: acute toxoplasmosis typically fatal
What are the clinical signs of Toxoplasma in Australian marsupials?
-sudden death
-neurologic symptoms
-resp. distress
-enteric disease
What are the general characteristics of human toxoplasmosis?
-leading cause of death attributed to food-borne illnesses
-most severe in immunocompromised individuals and pregnant women
What are the clinical signs associated with toxoplasmosis?
-may be asymptomatic
-flu-like
-swollen lymph nodes
-aches
-retinochoroiditis
-encephalitis
What are the clinical signs associated with toxoplasmosis in pregnant women?
-stillbirth
-congenital defects
-hydrocephaly
-abortion
-blindness
-epilepsy
When are pregnant women most at risk for transmitting Toxoplasma to their fetus?
between 10 and 26 weeks gestation
How is Toxoplasma diagnosed antemortem?
-fecal centrifugal flotation (cats only)
-biopsy/microscopic examination of tissues with IHC staining
-ELISA
-agglutination assay
-IFA
-MAT
How is toxoplasma diagnosed postmortem?
-microscopic examination of tissues (IHC)
-bioassay
-genotyping
What are the prevention/control measures for Toxoplasma?
-keep cats indoors
-prevent predation
-avoid untreated water
-discourage feral cat colonies
-no raw meat diets
-clean litter box daily
-cover outdoor sandboxes
-wash vegetables well
-cook meat well
-wash all kitchen surfaces/tools
-freeze meat
-pasteurize dairy products
-avoid raw oysters
What prevention measures should pregnant women take with Toxoplasma?
-have a titer done prior to pregnancy
-avoid cleaning litter box
-proper PPE for working with cats/litter box
-wash hands and kitchen items thoroughly
-wear PPE when working in garden
-avoid untreated water
What is important about Toxoplasmosis treatment?
there is no approved treatment for Toxo
What clinical signs are seen in adult dogs with Neospora?
-pneumonia
-hepatitis
-myocarditis
-skin lesions
What clinical signs are seen in congenitally infected puppies with Neospora?
-neuromuscular signs/hind limb paresis
-death
What clinical signs are seen in cattle with Neospora?
-abortion, esp. first pregnancy, around 4-6 mo. gestation
-congenital infections
How is Neospora diagnosed in dogs?
-fecal centrifugal flotation
-IFA/ELISA
-PCR
How is Neospora diagnosed in cattle?
-PCR on aborted fetus/placenta
-IFA
-histopathology
-histochemistry
What are the keys to Neospora control in cattle?
-culling positive animals
-preventing entry of infected replacements
-preventing oocyst contamination
What are the characteristics of Sarcocystis?
-predator/prey life cycle
-seen in all species; various DH and IH
-typically non-pathogenic in DH
-S. cruzi is most pathogenic to IH; causes abortion and neonatal disease (cattle, sheep, goats)
What are the life stages for Sarcocystis spp.?
-sporocysts (environment)
-merozoite
-sarcocyst
What are the characteristics of Sarcocystis neurona?
-DH is opossum
-IH includes armadillo, felids, skunk, raccoon, sea otters
-causes equine protozoal myeloencephalitis
-not zoonotic
What type of host is the horse for Sarcocystis neurona?
aberrant host
What are the clinical signs of Sarcocystis neurona in horses?
-lameness
-weakness
-muscle atrophy
-ataxia/incoordination/spasticity
-cranial nerve signs
How is Sarcocystis neurona diagnosed?
-fecal float (will be specific to DH species)
-clinical neurologic signs
-immunodiagnostics
-PCR
-response to treatment
What are the treatment goals for Sarcocystis neurona?
-reduce inflammation
-reduce brain/spinal cord edema
-eliminate causative organisms
How can Sarcocystis neurona be prevented/managed?
-store feed in tightly sealed containers
-keep wildlife out of feed areas
-do not feed/keep wildlife as pets
-keep compost pile away from pastures
