Review Flashcards
Trichuris (Enoplid) L1
Trichuris, general name? pathogenic? Expression of disease? Where do you see this parasite frequently?
*(whipworms)- embed anterior end under the mucosal lining to sit in tunnels and absorb nutrients, digest juices with stickosome oesophagus
* Mostly non-pathogenic- Immune response is not protective, so “accumulation” of infection– animals do not get rid of them like other parasites
* Occurs in the LI
* Typhlocolitis, colitis, mucoid enteritis and mucoid diarrhoea
* Large burdens = bleeding, blood in faeces
* large numbers of eggs excreted
* Seen in kennel situations
Ascaris suum, where? Migration? Who? Transmission route? Unique characteristics?
Ascaris suum
* Impacting large intestine
* HP migration- massive immune response
* Generally in young animals
* transmission route: simplest version of any ascarid: DIRECT– infective egg in the environment
* Prolific egg layers- sticky eggs
* Sandy environments- you can get rid of them- but generally in the environment they are difficult to get rid of especially in humid environments
* L3 is the infective stage- egg shell is still there in order to get through the stomach and to the SI
* Earthworms can carry eggs but MOST infections arise after ingesting L3 contaminated foodstuffs
Trichinella L1 in muscle
* 12 different species around the world; T. pseudospiralis and T. papua (Northern AUS)- not a major issue in AUS
* human health issue (raw meat contaminated)- induce acute GIT infection
* worms mate, produce larvae, and are injected into the lacteals in the SI–> muscles–> use their stillette to get in–> undergo muscle to moult so they can survive
* Main pathogenic effect in muscle: fever, myositis, myalgia (muscle pain)
* Hard to diagnose in animals
T. spiralis or Trichinella
T. papuae or T. pseudospiralis
Physocephalus sexalatus (via beetle) (Spiruroid)
Ascarops strongylina (pig– via beetle) (Spiruroid)
Why do we need to know the PPP?
To break the cycle with drugs
Where would you find these eggs? PPP?
Oxyuris equi- lays eggs around the anus
* PPP= 3 months
What might this be?
Where would the two possibilities normally occur?
Habronema microstoma or H. muscae or Draschia megastoma (Spiruroids)
* mostly occur in the stomach
* need the stomach to produce adults, to produce eggs to be excreted into the environment
Draschia megastoma (Spiruroid- horse)
Habronema microstoma or Habronema muscae (Spiruroid- horse)
Onchocerca gibsoni (Filarioids)
Heterakis
Toxocaris canis (Ascarid)
What’s the difference between T. cati and Toxocaris canis life cycle?
T. cati only Transmammary
Toxocara canis & cati (PPP is only different), stage passed in faeces? infective stage in soil? duration taken to reach infectivity in soil? PPP? What illness could a puppy have?
Stage passed in faeces: Egg- embryonated
Infective stage in soil: Larvae in the egg (L3)
Duraction taken to reach infectivity in soil: 2 weeks
How long will the eggs survive in soil: 5-10 years (thick and resistant)
PPP: Toxocara canis: 2-3 weeks (transplacental) to 4-5 weeks (ingestion egg)
* Toxocara cati 4 weeks (transmammary), to 6-8 weeks (ingestion)
* puppies get pneuomonia as well but not T. cati (not as pathogenic)
Why wouldn’t you expect to find Toxascaris leonina to be in a puppy?
No transmammary or TP transmission
* only way to get infected is by eating an IH like a mouse
* also because the PPP= 3 months– you wouldn’t see eggs in its poo for at least 3 months
Toxascaris leonina (Ascarid)
How would you treat current infection in pups and bitch Toxocara canis? Recommendations to breeder for future prevention of roundworm in bitch and pup? Breeder has a toddler at home, what advice would you give them?
Bitch before whelping: macrocyclic lactones– monthly (moxidectin or selemectin or injectable– kills larvae in circulation) **(may have encysted larvae– no way of telling)
Pups: pyrantel (every 2 weeks) until 2 weeks after weaning 3 months, then every month
** only drugs you can give puppies: drontel puppies (pyrantel and something else) or milbermycin (expensive) or pyrantel only.
** prevents A. caninum as well!!
** soil is contaminated– eggs stay in soil for years
What are the two main diseases in humans from Toxocara?
Visceral larva migrans (urticaria or fever, hepatomegaly, eosinophilia, cough) and ocular larva migrans (8 year old is mean age of presentation– causes blindness)
Trichuris vulpis
Would you expect egg to be infective upon passing?
No. It occurs in the environment.
Why would you never expect Trichuris vulpis in a puppy?
Because there is a long PPP. 10-12 weeks. Minimum age is 5-6 months.
What would you expect to see with heavy infections of Trichuris vulpis?
Typhlitis, colitis, diarrhoea with mucous +/- fresh blood, anaemia, tenesmus (straining to defecate)
Post-mortem stray dog in Delhi- aorta
Spirocerca lupi
What is the IH of Spirocerca lupi? DH?
Dung beetle (L3 develops within) and Dog
Spirocerca lupi
What may occur with a dog infected with S. lupi?
Aortic rupture, oesophageal granuloma– fibrosarcoma (eventually kills because it can’t eat), ectopic migration (paralysis, seizures)
How you do diagnose S. lupi? Prognosis?
Eggs look similar to another stomach worm AND eggs may not be present in faeces.
Endoscopy and radiography
** anorexia
Gnathostoma
Gnathostoma sprinigerum (humans)
When do you test for heart worm? What can indicate heartworm in a dog? What to treat? How to diagnose?
After 6 months– for example, they were taken off MLs for a period of time.
* Develops over 6-9 months
* Develop signs of coughing prior to 6 months
* Moxidectin (ML)- up to the age of 54-60 days
* Blood look for microfilaria & ELISA antigen
What happens with myointimal proliferation in heartworm?
* pulmonary artery thickens- becomes less elastic– needs to be elastic in order to comply with the heart pumping–> cause hypertension to develop
* leakage into the lung (congestion of the lung)
* leads to right sided congestive heart failure
* exacerbated by microthrombi from the worms
Toxocara canis
Macracanthorhynchus hirudinaceus
True or false Pseudophyllidea lay operculated eggs.
True
What clinical signs does Diphyllobothrium latum cause? LC? Is it in AUS?
* D. latum affects humans and carnivores
* Causes diarrhoea and abdominal discomfort, sometimes slight to severe anaemia due to vitamin B12 deficiency (assimilated by the worm) when worms are situated in the upper small intestine
* Egg–> coracidium–> procercoid (copepods)–> plerocercoid (freshwater fish)–> adult (humans, dogs, cats)
Diphyllobothrium latum (Pseudophyllidea)
Diphyllobothrium latum (Pseudophyllidea)
Diphyllobothrium latum
Hymenolepis nana
Dipylidium caninum
Taenia solium
Anoplocephala perfoliata
What is the endecticide that is effective against Anoplocephala in horses?
Praziquantel
IH ?
Fleas (Dipylidium caninum- Cyclophyllidea)
Amoebotaenia sphenoides
What if this was a pig heart and not a cow heart?
Taenia saginata
If pork- Taenia solium
Can a vegetarian be infected with Taenia solium causing neurocysticercosis?
Yes. Cysticercosis is an infection of both humans and pigs with the larval stages of the parasitic cestode, Taenia solium. Infection is caused by ingestion of eggs shed in the feces of a human tapeworm carrier. Pigs and humans become infected by ingesting eggs or gravid proglottids. Humans are infected by ingestion of food contaminated with feces or by autoinfection (reverse peristalsis).
Once eggs are ingested, oncospheres hatch in the intestine, invade the intestinal wall, and migrate to striated muscles as well as the brain, liver and other tissues where they develop into cysticerci
How do humans acquire hydatid disease (or cystic echinococcosis)?
Dogs eat offal contaminated with hydatid cysts–> cysts develop into adult tapeworms in the dog–> infected dogs shed tapeworm eggs and contaminate the ground (1 year viable)–> sheep, cattle, goats, and pigs ingest tapeworm eggs–> eggs hatch and develop in their internal organs–> humans can consume soil, water or food contaminated by the fecal matter of an infected dog.
What is alveolar echinococcosis?
Caused by infection with the larval stage of Echinococcus multilocularis. Adult tapeworm normally found in foxes, coyotes, and dogs. Infection with the larval stages is transmitted to people through ingestion of food or water contaminated with tapeworm eggs.
Echinococcus granulosus and Taenia hydatigena
How do cattle become infected with paramhistomes?
Cattle ingesting metacercariae encysted on aquatic vegetation
Calicophoron calicophorum and Paramphistomum ichikawai in Australia (Orthocoelium streptocoelium too)
Fasciola hepatica
What is acute and chronic fascioliasis in cattle vs. sheep?
* Acute is common in sheep- traumatic hepatitis due to large numbers of 5-6 week old flukes. Sheep often found dead. Chronic- damage to bile ducts which become thickened and enlarged; liver atrophies. Fibrosis and compensatory hypertrophy in other parts. Anaemia, hypoproteinaemia, bottle jaw, ascites.
* Black disease in sheep- acute toxaemia due to multiplication of flukes; sudden death and rapid decomposition
* Cattle- acute fascioliasis is very rare. Chronic is common and important. Fibrotic bile ducts and calcification. Black disease occurs occasionally. Encapsulated aberrant flukes sometimes seen in lungs (granulomata).
Found in sheep bile duct
Dicrocoelium dendriticum (paramhistome)
PPP of Dicrocoelium dendriticum?
8-12 weeks
For Cryptosporidium, following schizogony and gametogony, which of the following most accurately describes the life cycle?
Thick and thin walled (auto infective) oocyst formation, sporulation in the host, shedding into the environment
Giardia trophozoites on intestinal villi
Balantidium trophozoites
Is Dicrocoelium dendriticum in Australia?
No.
Schistosomiasis is a very important human health problem (200-300 million infected)
Schistosoma mansoni, S. japonicum, S. haematobium- humans. Ruminants- S. bovis, S. nasale, S. mattheei
** Blood vessels- location depends on species– e.g. protal and/ or mesenteric vessels, vessels of the bladder, or nasal mucosa.
* Skin (cercarial penetration)–> vessel damage (adults)–> genulomata (eggs)
S. japonicum- “rice farmer’s disease” in Asia- determined by climate, snail habitat, and host range
NOT IN AUS
** control reduce exposure to cercariae, treatment with praziquantel
* LC: Egg–> miracidium–> sporocyst-cercariae (aquatic snail)–> penetrate skin–> schistosomule (blood stream)- adult (vessels).
Name 3 genera in Australia? Treatment?
Closantel and oxyclozanide
(Niclosamide and Oxyclozanide)
Faecal examination of diarrhoeic dog (approx 5-6 micrometers in size)
Cryptosporidium- detection of oocysts in faeces. Acid fast and stain well with basic fuchsin. Must be differentiated from Cyclospora cayetanensis (in humans and primates causes disease)
What are the three major hosts for Dicrocoelium dendriticum?
land snails, ants and ruminants
Trypanosoma in the blood
Which stages of the Fasciola life-cyce occur in the snail?
Sporocyst and rediae. Miracidium swims actively to find a snail IH. Sporocyst and rediae inside the snail and cercariae. Cercariae escape from the snail and encyst on vegetation as metacercariae. Ingested at this stage.
Treatment of Fasciola hepatica? Control?
Drenching with Triclabendazole or oxyclozanide. Drainage; fencing off water ways.
Davainea proglottina
In the trematode life-cycle the mollusc is?
An IH and usually a snail
Orthocoelium juveniles
Pathogenesis of coccidosis due to Eimeria?
* Epithelial destruction due to intracellular schizogony and tissue sloughing due to invasion of the lamina propria
Life cycle of Eimeria
Oral ingestion, schizogony and gametogony in intestinal epithelial cells, oocysts shed into the environment sporulation
Would faecal floatation using saturated salt solution aid in the diagnosis of Tritichomonas foetus in cats?
No
Eimeria
Chronic fascioliasis
How is Giardia transmitted?
Via ingestion of cysts, eitehr directly or via contaminated food and water
What is the most likely zoonotic source of human infection with Cryptosporidium?
Calves
Can Neospora be transplacentally transmitted in cattle?
Yes
Which stage does Toxoplasma cross the placenta?
Tachyzoite
Babesia bigemina is transmitted by?
Rhipicephalus microplus
Treat with toltazuril, provide supportive therapy, quarantine and clean the environment of faecal contamination with ammonia compounds
Common cause of diarrhoea in vertebrates
Giardia duodenalis
Pathogenesis of toxoplasmosis?
Tachyzoites replicating intracellularly in host tissues causing localized destruction and inflammation
How long after infection do cattle show signs of acute paramhistomiasis?
5-6 weeks
Which two species of canine Babesia are present in Australia?
Babesia vogeli and Babesia gibsoni
Common parasite that causes abortions in sheep
Toxoplasma gondii
Trichomonas gallinae
Which stages can be involved in asexual reproduction in the snail?
Miracidium, sporocyst, and redia
A common parasite causing colitis in kitten is:
Tritrichomonas foetus
What is a drug that is a suitable control component for coccidiosis?
Toltrazuril
Victorian sheep liver on necropsy. This liver shows signs of:
Acute fascioliasis
A potential IH for Fasciola
How do dogs become infected with Sarcocystis?
Ingestion of uncooked meat
What is the definitive host of Toxoplasma gondii?
Cats
What are three possibilities for the trematode life cycle?
- Miracidium, Cercariae, Sporocyst, Redia, Metacercariae, Juvenile, Adult
- Miracidium, Sporocyst, Cercariae, Metacercaria, Juvenile, Adult
- Miracidium, Sporocyst, Cercariae, Juvenile, Adult
Cystoisospora
Histomonas meleagridis
Eimeria tenella
Toxoplasma gondii
Treatment of Giardia (regime) or GI worms in pups (regime)
Febantel for 3 days
Praziquantel every four weeks
Treating pups for GI worms
Every 2 weeks for 12 weeks- pyrantel
In a histo section, wth Eimeria tenella, what would you expect to see?
Schizonts, micro and macro gametes
What is the PPP of Trichuris vulpis?
Giardia produce?
Crypto produce?
Helminths produce?
giardia- Cysts
crypto- Oocysts
Helminths- eggs
Cyst with equal parts from a dog or cat?
Cystoisospora
* kennel situations- stress, diarrhoae- Cystoisospora commonly seen.
* Neospora (and Isospora??) Identical cysts to Toxoplasma (Toxo- cat, not in a dog)
Persistent, recurring diarrhoea in dirty environments in dogs, pigs, primates (not horses or cattle)
Trichuris vulpis- whipworm
How long does it take for hookworm to get to L3 in the environment?
1 week (only 1 day to get to L1)
Control of taeniid cestodes. What about larval stages?
* Education campaigns
* regular monthly treatment of dogs with praziquantel
* monitoring of success in IH by abattoir surveillance
*(vaccines in the future as they have been developed)
** Larval stages benzimidazole against cystic and alveolar hydatidosis usually in combination with surgery
