Apicomplexa Flashcards
What are the Apicomplexas we are concerned about?
Eimeria Cystoisospora Cryptosporidium Toxoplasm Neospora Sarcocystis
Most of the effective drugs to the Apicomplexa work against what?
Apicoplast
What are the three basic life cycles of Apicomplexa?
Sporogony (Becomes infectious)
Gametogony (Sexual reproduction)
Merogony (Asexual phase happens in vector)
Which Apicomplexa has the simplest life cycle?
Eimeria
Eimeria are ________ parasites that are usually in the _________ cells
obligate intracellular
gut epithelial
How is Eimeria transmitted? What is the infective stage? Where does it develop? What is passed in the feces?
Fecal-oral
Sporulated oocyst
Sporulates in the environment
Non-infective, non-sporulated oocyst
Describe the life cycle of Eimeria starting with a non-sporulated oocyst
It contains a single sporont
Undergo sporogony to become infective.
Sporont undergoes two divisions to form 4 sporoblasts
Sporoblast develops into a sporocyst with 2 sporozoites
How many sporozoites does a sporulated oocyst have?
8
Where does sporogony occur for Eimeria?
In the environment
What temperature causes oocysts to sporulate faster?
Warmer temperature
What is the asexual proliferation phase called?
Merogany
In merogany, what do the sporozoites become?
Merozoites
Final asexual generation of merozoites proceed to what?
Gametogony
_____ is the sexual reproduction phase. What do the females become? Males?
Gametogony
Microgametes
Macrogametes
T/F There is no zoonosis in Eimeria species
TRUE; there is no crossover
T/F Immunity to Eimeria is species specific; there is absolutely no cross over
TRUE; once again. No crossover
What does clinical disease associated with Eimeria come from?
The amount of oocysts that are ingested
species
Host factors
What is the lag time for oocyst detection and clinical signs from Eimeria?
Clinical signs can usually be seen 1-2 days before the oocysts can be detected in feces
What are the three types of coccidiosis?
Winter, enteric, and nervous
_______ coccidiosis has clinical signs that are seen in Janurary to MArch
Winter
Where do cocidiosis lesions occur?
Distal ileum lesions are associated with the asexual phase
Cecum/colon is associated with the sexual stage
What steps could you take to control/prevent bovine coccidiosis?
Remove and treat clinical cases
Minimize crowding/improve sanitation
Keep feces out of water/feed
Kill oocytes with sunlight and dessication
What is the most pathogenic Eimeria in small ruminants
Eimeria ovinoidalis
What is the Eimeria that infects the ceca of chickens? The small intestine?
Eimeria tenella
Eimeria necatrix
What causes hepatic coccidosis in rabbits?
Eimeria stiedae
What is the one difference between Eimeria and Isospora?
Isospora often utilizes a paratenic host
Dogs infected with cystoisospora sheds what in feces? What is infective? Where does sporogony take place?
Unsporulated oocyst
Sporulated oocyst
Environment
What are some clinical signs associated with cystoisospora infection? Where are these most common?
anorexia, weight loss, possible vomiting. Can see oocysts in feces
Seen in kennels or catteries
What is unique about cystoisospora oocysts?
They have no micropyle cap
They have only 2 sporocysts
4 sporozoites per sporocyst
What is the best way to control cystoisospora?
Saitation and post-partum treatment of queen or bitch
__________ is the cystoisospora that is ubiquitous with swine and causes neonatal diarrhea
Cystoisospora suis
T/F Snail is a common paratenic host for Cystoisospora suis
FALSE; there generally is no PH for this
Where would you look to complete a post-mortem diagnosis for Cystoisospora suis?
Jejunum and duodenum for fibronecrotic membranes
What are the treatments of choice for Cystoisospora suis?
Toltrazuril and Diclazuril
_____ causes cryptosporidosis
Cryptosporidium
Intestinal cryptosporidia in humans and cattle is most commonly caused by what?
Cryptosporidium parvum
What is unique about Cryptosporidium parvum?
Sporogony occurs within the host
What type of Cryptosporidium parvum infects cattle? Humans?
Type 1
Type 2
The sporulated oocyst of Cryptosporidium parvum has how many sporozoites?
4
What are the two types of oocysts that Cryptosporidium parvum produces?
Thick shelled
Thin shelled
What are the differences between the thick shelled and thin shelled oocysts of Cryptosporidium?
Thick shelled are passed in feces
Thin shelled is auto-infective
T/F Cryptosporidium is zoonotic
TRUE; it can give ya the screamers
T/F Cryptosporidium must be treated, even in the immune competent host
FALSE; this is usually self limiting as the system catches up
What would you use to diagnose cryptosporidium ante-mortem?
Sugar fecal float
Oocysts will be pale pink and refractile in this solution
What is the treatment for Cryptosporidium?
Eh, idk nothing really works.
Provide supportive care
What is difficult about preventing and controlling Cryptosporidium in a herd?
It is autoinfective so just limiting the oocyst exposure may not work.
Water purification also does not eliminate Cryptosporidium
How can you kill cryptosporidium oocyst/
Repeated thawing and freezing
What is the cause of Toxoplasmosis?
Toxoplasma gondii
T/F Toxoplasma gondii can infect all warm blooded animals and is highly zoonotic
TRUE
What is different about the Tozoplasma gondii life cycle?
They have tachyzoites and bradyzoites
What are tachyzoites? Bradyzoites?
Tachyzoites: quick proliferating intracellular stage
Bradyzoites: slow proliferating stage within a tissue cyst
What is the source of infection for Toxoplasma gondii?
Sporulated oocyst ingestion
Ingest tissue cyst with bradyzoites from IH
Transplacentally via tachyzoites
What is the definitive host for Toxoplasma gondii? What is the life cycle like?
Cats
Merogony and gametogony occur in the GI tract. Shed unsporulated oocysts.
Extra-intestinal reproduction also occurs: tachyzoites in any cell, bradyzoites in tissue cysts.
What is the life cycle of Toxoplasma gondii in the intermediate host? What is an intermediate host?
Infection via ingestion of sporulated oocysts
ONLY intracellular takes place
Tachyzoites and bradyzoites can be found in the brain, eyes, and muscle
Mammals and basically any animal.
T/F Intermediate hosts infected with Toxoplasma gondii shed oocysts
FALSE
T/F Cysts in the IH persist for the life of the animal
TRUE
Can tachyzoites be cleared by an immune-competent host?
Yes. When the cyst walls break down and release the bradyzoites, which then find a new cell, they revert back to tachyzoites which can be cleared
What are the clinical signs of animals infected with Toxoplasma gondii?
Generally asymptomatic
Tachyzoites can cause inflammation in multiple organ systems
T/F Cats only shed oocysts of Toxoplasma gondii once in their life
TRUE; they only shed oocysts after their first primary exposure
What symptoms would you see in humans infected with Toxoplasma gondii?
Flu-like symptoms in immune competent adults
Encephalitis in immune compromised adults
What would you do to diagnose Toxoplasma gondii?
Fecal floats to detect the oocysts
How do you prevent infection with Toxoplasma gondii?
Prevent the ingestion of tissue cysts (wear gloves when handling raw meat)
Wash hands after handling raw meat
Don’t drink unpasteurized goat milk
Prevent oocyte sporulation and ingestion
How do you prevent cats from becoming infected with Toxoplasma gondii?
Prevent hunting, don’t feed raw meat, and clean out the litter box daily.
________ is only known to have dogs and coyotes as its definitive host
Neospora caninum
Neospora caninum uses what for intermediate hosts?
Cattle and deer
How can infection of Neospora caninum occur?
Ingestion of sporulated oocysts
Ingestion of tissue cysts with bradyzoites
Transplacental transfer of tachyzoites (MOST COMMON)
What is the life cycle of Neospora caninum in the dog?
intestinal merogony and gametogony
Non-sporulated oocysts shed in the feces
Extra-intestinal occurs in all hosts
Sporozoites or bradyzoites become tachyzoites, which can infect any cell type and can usually cause the problems
What is different about the Neospora caninum cysts?
They have much thicker walls than the Toxoplasma gondii ones.
Bovine _____ is a major cause of cattle abortions worldwide
neosporosis
Inflammation of the placenta and fetus in cattle is associated with what form of Neospora caninum?
Tachyzoites
How do you prevent your cattle from becoming infected with Neospora caninum?
Usually endemic resulting from transplacental infection
Can see outbreaks with feed and dog feces
Canine neosporosis is usually a problem in _____ and is a result of ______ infection
Pups
congenital
What are some of the signs of canine neosporosis?
Leg weakness and ataxia
Can progress to paralysis of the hind limbs
What causes protozoal myeloencephalitis?
Sarcocystosis
What is the life cycle of Sarcocystis?
Obligate indirect cycle involving 2 hosts
Carnivore is definitive host
Herbivore is intermediate host
Describe the life cycle of Sarcocystis in the intermediate host
Merogony: muscular phase that is initiated by merozoites from last stage of merogony
gives rise to cysts with bradyzoites in mature muscles that persist for the life of the host
Describe the life cycle of sarcocystis in the definitive host
Infection occurs via ingestion of bradyzoites, from the tissue cysts in IH.
Bradyzoites infect enterocytes; undergo gametogony and produce oocysts.
Oocysts sporulate in the gut, produces sporocysts or sporulated oocysts in the feces
T/F Sarcocystis is immediately infective once it is passes in the feces of carnivores
TRUE; sheds sporozoites or sporulated oocysts
What Sarcocystis species causes Equine protozoal myelitis
Sarcocystis neurona
What is the definitive host for Sarcocystis neurona?
Opossum
T/F Sarcocystis neurona is not really a big problem in the US
FALSE; if you see a horse with CNS type disease this should raise on your list of differentials
T/F Horses are an abberrant intermediate host for Sarcocystis neurona
TRUE; they are a dead end intermediate host
What are some signs associated with equine protozoal myeloencephalitis ?
Focal, soft, discolored areas of the spinal cord that are generally asymmetric
Usually are just general CNS clinical signs
What are some risk factors for equine protozoal myeloencephalitis?
Opossums in your barn
Barns near your farm
How do you diagnose equine protozoal myeloencephalitis?
This is more or less a rule out lesion
