Week 4 Flashcards
Rumen Flukes
Rumen flukes
What Paramphistomes of Australia are found in the following snails? Where are they found geographically?
Widely distributed VIC, TAS, Coastal NSW, Tropical wet QLD, WA
What is the life cycle of Paramphistomes?
What is the pathogenesis of paramhistones?
* First 1-2 months
* Enteritis: juvenile flukes attach, feed in duodenum/ upper jejunum
* adults cause no harm
* exposure increased immunity
* Weaners or immuno-naive animals (introduced animals) most susceptible
- drought, movement, stressed
Paramhistones
Clinical signs of paramhistones
* Light infection- asymptomatic
* moderate- ill thrift, reduced weight gain, loss milk production
* heavy- up to 72K worms- water diarrhoea, dehydration and death
Diagnosis of paramhistones
* difficult because usually unaware of infection, post mortem, NO eggs in faeces– because juveniles cause signs and symptoms and PPP is 3 months
Paramhistones
Treatment and Control of paramhistomes
* Fence/ drain affected areas
* Anthelmintics- none specifically registered in Australia against parahistomes (extra-label use- clostantel 10 mg/kg, oxyclozanide 15 mg/kg)
* Adult flukes in rumen- reduce contamination of pasture for next cycle, later winter
* Juvenile flukes- treat/ prevent clinical disease, summer- early winter
Dicrocoelium dentriticum (Dicrocoelium, Snail IH- Cionella- ant is 2nd IH)– ruminants, horses, pigs, humans
Dicrocoelium dentriticum (Dicrocoelium, Snail IH- Cionella- ant is 2nd IH)– ruminants, horses, pigs, humans
Life cycle of Dicrocoelium dentriticum (Dicrocoelium, Snail IH- Cionella- ant is 2nd IH)– ruminants, horses, pigs, humans
Significance of this parasite- what is its?
Dicrocoelium
Treatment and control of Dicrocoelium
* very difficult!
* Benzimidazoles (e.g. albendazole) at high dose (e.g. 20 mg/kg)
* Praziquantel
why are fish borne liver flukes important for us? What are the two main genera?
* use animals and humans as reservoirs
* Opisthorichis and Clonorchis
What are signs of opisthorichis and Clonorchis?
* Asymptomatic
* Gall bladder stones
* Cholangitis, jaundice
*Cholagiocarcinoma
Cholangiocarcinoma
Clonorchis
Opisthorichis and Clonorchis Life Cycle
Risk factors of opisthorichis and clonorchis?
* traditional dietary practices of eating raw, fermented, or pickled fish
* Poor sanitation- use of animal or human effluent as fish food
* Uncontrolled reservoir host population (free roaming, dogs, cats, and pigs)
Control and prevention of opisthorichis and Clonorchis?
* monitor and chemotherapy- mass praziquantel for humans, praziquantel baits reservoir hosts
* education: alter traditional eating practices, cook fish, or free at 20 below C for > 24 hours
* indoor defaecation
* do not feed raw fish to dogs and cats
Paragonimus spp. Life Cycle
Paragonimiasis
Paragonimiasis
General Paragonimiasis
* endemic in SE Asia, the Americas
*Zoonosis that requires reservoir control in order to control in humans
* Canids and felids reservoir
* Resembles TB in the lungs
* Pulmonary forms: cough, haemoptysis, “non-responsive tuberculosis”
* 30% of extra-pulmonary (brain, abdominal- juvenile forms “wander)
* Treatment with praziquantel
Schistosomiosis
* Blook flukes (vessels- portal, mesenteric, bladder, and other)
* Human pathogens; not in Australia
* affecting 200-300 million people
Schistosoma
Morphology of Schistosoma
* in-copula (female in groove)– get together inside and stay that way
0.5- 2 cm long
What Schisotosoma lives in China and parts of SE Asia?
S. japonicum
(in the lake and marshy regions despite successful control in other endemic areas)
Schistosoma Life Cycle
* Adults live in bladder or mesentery–> shed eggs within the venules–> get to the lumen of the bladder or intestine–> passed by urine or faeces–> eggs embryonated when they pass (spines)–>miracidia hatch straight away–> snails–> sporocyts in snail–> penetrate skin of humans
What snail does S. japonicum use?
Oncomelania quadrasi; Philippines (tiny snail)
Risks for S. japonicum
* Risks: rice farming, fishing, swimming
* Zoonosis: water buffalo, cattle, pigs, dogs, cats
* Philippines, Indonesia, SE China
Acute Schistosomiosis
* Self-limiting deramtitis (24 hrs)
* Delayed hypersensitivity response (3-4 weeks)
- TH1 pro-inflammatory response
- hypereosinophilia
- fever, arthralgia, bronchiopneumonia, and urticaria or angio-oedema
Chronic Schistosomiosis
* Eggs laid within venules of urinary bladder/ distal colon and rectum
* Eggs penetrate venule and intestinal/ bladder wall using spine and proteolytic enzymes to enter lumen and be passed
* Some eggs lodge in organs causing granulomas esp. intestines, liver, bladder
- ectopic sites e.g. brain
* Portal and pulmonary hypertension, ascites, HIV/AIDs complications
* Worm antigens in circulation- antibody- mediated glomerulonephritis (massive loss of proteins therefore exacerbated ascites- why they have such a big stomach)
* Fibrosis, neoplasia, amyloidosis
Diagnosis of Schistosomiosis
* History/ clinical signs
* Eggs in faeces/ urine
* Serology
S. japonicum (looking for the tiny spine)
Control of Schistosomiosis
* mass treat with praziquantel to reduce burden and egg shedding and therefore clinical signs– not overly effective because reinfection occurs straight away
** better: improve household sanitation and access to clean water (not using the toilet in the water)– won’t work for S. japonicum because it uses animal reservoirs!!
** REPLACING water buffaloes with mechanical TOOLS (found it was not sustainable, but it worked)
* Educating fishermen and boatmen about the dangers of infested water
* Molluscicidal treatment (not overly effective)- miss a few snails–> asexual copulation–> cycle starts again
* Vaccines are in development- they can reduce worm burden up to 40% in some individuals
Swimmers Itch
Cercarial dermatitis
* Common in AUS
* Austrobilharzia or Trichobilharzia (aquatic birds)
* Self limiting HS rxn in about 24-28 hours
* Skin penetration of the “wrong host”
What are the parasites that impact the following ruminants & pigs ??
(Visceral Schistosomiasis)
Similar to humans- but no where near as severe
**production loss- low to moderate burden
** higher burdens younger animals- diarrhoea, haematuria, ascites, wasting
** Severely affected animals deteriorate rapidly and usually die wthin a few months of infection
Visceral Schistosomiasis
