Term
| Trematodes that we are interested in b/c they infect mammals |
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Definition
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Term
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Definition
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Term
| LC type of Digenean trematodes |
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Definition
| invariably indirect and complex (w >1 IH) |
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Term
| What organs do most Digenean trematodes infect |
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Definition
| gut and it's assd organs (liver, pancreas) |
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Term
| Trematodes - parenchyma or pseudocoelom |
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Definition
| cellular parenchyma surrounds organs |
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Term
| What surrounds trematodes (equivalent of cuticle) |
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Definition
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Term
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Definition
| all digenean trematodes (except Schistosomatidae) are hermaphrodite |
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Term
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Definition
| always a snail - usually aquatic (therefore only eggs that are in faeces that is dropped near water will enter IH) |
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Term
| Lc of digenean trematodes is entirely dependant on... |
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Definition
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Term
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Definition
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Term
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Definition
| ellipsoidal or ovoi with operculum at one end with morula - dvps to miracidium usually after egg has left DH |
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Term
| Miracidium hatches from egg in response to |
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Definition
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Term
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Definition
| It is ciliated and swims rapidly in water. It has a short life span therefore must encounter snail host witin a few hrs |
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Term
| How does the miracidium enter the IH |
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Definition
| it bores into the snail foot w using enzymes |
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Term
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Definition
| Second larval stage. once the miracidium has entered the snail IH it loses it's cilia and dvps to the second larval stage. |
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Term
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Definition
Sac like structure with:
1. Inside it are germinal cells that dvp to the next stage = Redia
2.Several Rediae dvp within each sporocyst and when mature burst through the sporocyst wall.
3.sporocysts may b/c large and branched - usually in LC where Redia stage is omitted. |
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Term
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Definition
| Dvp from germinal cells within the sporocyst. Several rediae dvp within one sporocyst |
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Term
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Definition
| is elongate and has mouth and simple gut. Is motile and usually migrates to the hepato-pancreas of the snail (highly nutritive) Germinal cells within the redia dvp into Cercaria - many cercaria are formed within one redia. When mature they leave the redia through birth pore |
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Term
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Definition
| dvp from germinal cells within the redia. there are many cercaria from one redia. |
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Term
| When mature the cercaria leave the redia through... |
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Definition
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Term
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Definition
| body (w suckers, gut and flame cells) and a tail - used to propel the cercaria in water |
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Term
| what is the last stage of trematode to dvp in and leave the snail IH |
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Definition
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Term
| List the stages (from L1 through to infective stage) larvae |
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Definition
| mircidium - sporocyst - redia - cercaria - metacercaria |
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Term
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Definition
| once cercaria have left the snail IH they encyst to b/c metacercaria - they secrete a cyst around themselves and shed their tails. where encystment occurs depends on spp. |
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Term
| Where can encystment of cercariae (formation of metacercaria) occur? |
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Definition
1.on vegetation in water
2.on/in 1st IH
3.on/in 2nd IH (commonly a fish) |
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Term
| What is the route of infection of Digenean trematodes to DH |
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Definition
| ingestion of metacercaria - encysts in the intest of the DH and dvps to maturity either there/after migrating to appropriate site |
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Term
| infective stage of Schistosomatidae |
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Definition
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Term
| Route of infection of Schistosomatidae to DH |
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Definition
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Term
| Which larval stages of digenean trematodes swim in water |
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Definition
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Term
| Fasciolids are parasites of where |
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Definition
| bile ducts or intestine of ani's |
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Term
| Species of snail that fasciola genus use as IH |
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Definition
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Term
| Host and organ of Fasciola hepatica |
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Definition
| many spp, but most import in Rts, bile ducts |
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Term
| host and organ of Fasciola gigantica |
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Definition
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Term
| what stage do Fasciola hepatica eggs contain when they are laid |
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Definition
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Term
| What do adult Fasciola hepatica flukes feed on |
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Definition
| they feed on the bile duct lining, blood and bile. This causes the bile duct ep to b/c thick and hyperplastic |
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Term
| What effect do Fasciola heptica flukes have on the bile ducts |
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Definition
| they cause thickening and hyperplasia of the ep |
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Term
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Definition
| freshwater, air breathing snails. |
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Term
| Lymnaeid sp that is indigenous to nz |
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Definition
| Lymnaea tomentosa. Found in spring fed marshes, sluggish streams and ponds |
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Term
| What are the three Lymnaeid sp in NZ that transmit Fasciola |
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Definition
| Lymnaea tomentosa, Lymnaea columella, Lymnaea trunculata |
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Term
| Describe the distribution of Lymnaea tomentosa |
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Definition
| widely distributed, but only numerous in some areas |
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Term
| Describe the distribution of Lymnaea trunculata |
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Definition
| Found only in Nelson Lakes are and some parts of Marlborough. Rqs comparatively little water for breeding (breeds well in mud) |
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Term
| Describe the distributon of Lymnaea columella |
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Definition
| Widespread in North Is and Nelson-Westland, near Timaru and Alexandra. Is responsible for increase in Fasciola hepatica in recent years |
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Term
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Definition
| marshes, slow streams and ponds. therefore when looking for Lymnaeids this is where to look |
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Term
| ID of Lymnaeids is based on |
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Definition
| shape of tentacles and characteristics of the shell |
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Term
| Where are Lymnaea columella from |
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Definition
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Term
| Where is Lymnaea trunculata from |
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Definition
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Term
| Adult fluke egg production |
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Definition
| very prolific up to 10 000eggs/day |
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Term
| Usually only which eggs dvp |
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Definition
| those that drop into water |
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Term
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Definition
| water, temp >10C, O2 (O2 tension in faeces is very low and being in faeces inhibits dvt) |
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Term
| Optimum temp for dvt of miracidium in egg |
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Definition
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Term
| How does Miracidium hatch from egg |
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Definition
| In response to light (light sensitive eye spots) it secretes enzymes that weaken the opercular seal. Water enters egg - causes gel cushion beneath the operculum to swell. P increases inside egg - lid pops off - miracidium swims out |
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Term
| The time that miracidium remains infective for after hatching depends on.. |
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Definition
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Term
| Miracidium swimming is random, what happens if it swims passed a lymnaeid |
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Definition
| it responds to chemotactic stim by circling to locate the snail |
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Term
| How does the miracidium enter lymnaeid |
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Definition
| attaches with it's apical papilla - secretes enzymes that break down the integument - using mm activity penetrates the snails tissues. |
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Term
| When does the miracidium b/c a sporocyst |
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Definition
| When it enters the lymnaeid it loses it's cilia and b/c's the sporocyst |
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Term
| How many rediae dvt within the sporocyst |
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Definition
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Term
| When rediae burst out of the sporocyst where do they go |
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Definition
| hepatopancreas (digestive gland) of the snail |
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Term
| What does the Redia feed on |
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Definition
| redia has a mouth and sac-like gut - feeds on protein and glycogen rich hepatopancreas |
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Term
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Definition
| norm cercaria dvp within the redia, but occasionally a second generation of rediae dvp first |
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Term
| What part of the cercaria produces the metacercarial cyst |
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Definition
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Term
| How many cercariae can dvp in one redia |
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Definition
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Term
| where do the cercaria leave the redia |
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Definition
| "birth pore" they then accumulate in the snail tissues for a while. |
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Term
| What stim causes the cercaria to swim out of the snail? |
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Definition
| drop in temp and providing the snail is in water |
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Term
| Dvt of Fasciola hepatica larvae within the lymnaeid rq's a temp of... |
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Definition
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Term
| Time from infection of snail to release of cercariae |
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Definition
| min 5 weeks, but in field often takes 2-3 months |
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Term
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Definition
| produce larger numbers of cercariae, b/c the larvae compete with the snail for nutrients |
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Term
| Once released from snail, what happens to cercariae |
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Definition
| swim about until they reach a firm surface eg. grass - attaches with vt sucker - tail is cast off - cystogenous gland starts to secrete cyst wall around cercaria (takes 24 hr) = metacercaria, is now infective to the DH |
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Term
| Numbers that one Miracidium can produce |
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Definition
| 1 miracidium x 12 rediae x 40 cercariae = 480 (maximum) |
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Term
| How long, under optimum conditions, does it take for dvt of larval stage in egg |
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Definition
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Term
| Name 2 factors that impair survival of metacercariae |
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Definition
| direct sunlight, dessication |
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Term
| Host of Fasciola hepatica |
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Definition
| not spp specific. Best adapted to S/G, but commonly infect C and rabbits, deer, possums, pigs, horses and humans |
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Term
| Post-ingestion, where does excystment occur? |
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Definition
In SI in response to chem stim:
1.high dissolved CO2 conc
2.low redox potential
3.bile salts
Nb. enzymes improve excystment rates but aren't essential |
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Term
| Migration of Fasciola hepatica from SI (jj) |
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Definition
| young fluke eats through the intestinal wall into peritoneal cavity - migrates to the liver - enters liver by eating through liver capsule (usually in the vt liver due to being in the lower part of abd due to gravity) |
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Term
| How long after infection does the young fluke enter the liver |
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Definition
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Term
| once in the liver, liver fluke... |
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Definition
| wanders in parenchyma for 5-6 weeks, feeds on liver tissue (leaving migration tracks) and growing |
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Term
| After being in the liver for 5-6 weeks the fluke... |
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Definition
| enters the bile ducts where it grows to maturity. 3-4 weeks |
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Term
| Once in the bile duct how long does it take for the fluke to reach maturity |
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Definition
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Term
| Minimum PPP of Fasciola hepatica |
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Definition
| 8 weeks, often longer tho |
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Term
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Definition
| dz caused by immature migrating flukes in tthe liver. if lots migrate simultaneously a sheep can die. no longer common |
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Term
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Definition
| Tissue necrosis in the liver caused by flukes may allow multiplication of Clostridium novyi, and sheep die of toxemia. no longer common |
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Term
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Definition
| fill with necrotic tissue and blood. They heal by fibrosis and the liver remains scarred. |
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Term
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Definition
common. caused by adult flukes in the bile ducts. dz results from feeding activity of flukes and partial obstruction of bile flow. Bile b/c thick and glutinous w excess mucus. Bile ducts b/c hyperplastic and dilated and prominent (in cattle can calcify)
Cliical signs - interference with growth and production, anaemia and hypoalbuminaemia.
High burdens (250 flukes) can cause sheep death (1000 in cattle) |
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Term
| Do sheep dvp resistance to Fasciola hepatica |
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Definition
| no, and the fluke is very long lived in the DH. Cattle dvp some resistance - can reject established flukes and prevent new infestations |
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Term
| What is the minimum generation time (egg to egg) for Fasciola hepatica |
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Definition
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Term
| What are the 2 ecological factors that dominate the LC of Fasciola hepatica |
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Definition
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Term
| Dvt of miracidium in the snail rqs temp to be above... |
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Definition
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Term
| is it water or air temperature that determines the dvt of miracidium |
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Definition
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Term
| Few snails survive the temperatures in winter, but if some that do were infected they will release cercariae when |
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Definition
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Term
| when is the first wave of larvae dvt complete after winter |
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Definition
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Term
| most Fasciola hepatica larvae dvt is completed in what seasons |
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Definition
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Term
| most Fasciola hepatica larvae dvt is completed in what seasons |
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Definition
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Term
| most Fasciola hepatica larvae dvt (and therefore most cercariae release) is completed in what seasons |
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Definition
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Term
| principal factor determining the length of the transmission period (release of cercariae etc) |
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Definition
| length of time temps exceed 10C throughout the year |
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Term
| is rate of infection of pasture with metacercariae related to snail population densities? |
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Definition
| No, the more snails avail, the more chance a miracidium has of infecting one, but snails are more likely to be in competition for food, poorer fed snails produce fewer cercariae than better fed ones - high pasture densities can occur with v low snail popn, but they are large and well fed |
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Term
| How does rainfall affect pasture density of metacecariae |
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Definition
| Lymnaea trunculata (European) lives on margins and muddy areas - when there is high rainfall, the area of snail habitat increases which results in larger areas of pasture contaminated with metacercariae - higher rates of ani infection. Not so much an issue in NZ(b/c snails are more permanently aquatic) |
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Term
| In NZ why is it that in dry years rate of infection of stock with Fasciola hepatica may be worse |
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Definition
| because stock may be forced to graze closer to water where the grass remains green (and we have less Lymnaea trunculata) |
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Term
| What effects would you expect prolonged hot, dry weather to have on snail breeding |
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Definition
| rate of egg dvt would increase but shortage of food and water havitat would decrease snail eggs laid and their survival |
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Term
| What effects would you expect prolonged hot, dry weather to have on metacercarial survival |
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Definition
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Term
| What effects would you expect prolonged hot, dry weather to have on cercarial release |
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Definition
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Term
| What effects would you expect prolonged hot, dry weather to have on redial dvt |
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Definition
| more rapid, but numbers could be adversly affected by poor snail nutrition |
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Term
| What effects would you expect prolonged hot, dry weather to have on fluke egg dvt |
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Definition
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Term
| What effects would you expect prolonged hot, dry weather to have on fluke egg survival |
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Definition
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Term
| What effects would you expect prolonged hot, dry weather to have on fluke egg production |
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Definition
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Term
| What effects would you expect a sudden drop in temp to below 10C to have on fluke egg hatching |
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Definition
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Term
| What effects would you expect a sudden drop in temp to below 10C to have on snail breeding |
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Definition
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Term
| What effects would you expect a sudden drop in temp to below 10C to have on fluke egg survival |
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Definition
| increased, provided there is adequate moisture |
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Term
| What effects would you expect a sudden drop in temp to below 10C to have on fluke egg dvt |
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Definition
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Term
| What effects would you expect a sudden drop in temp to below 10C to have on redial dvt |
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Definition
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|
Term
| What effects would you expect a sudden drop in temp to below 10C to have on cercarial release |
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Definition
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Term
| What effects would you expect a sudden drop in temp to below 10C to have on metacercarial survival |
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Definition
| increased, provided adequate moisture |
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Term
| Cyclophyllidea: what do the testes discharge into |
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Definition
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Term
| Cyclophyllidea: what do the vas efferentia discharge into |
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Definition
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Term
| Cyclophyllidea: what does the vas deferens open into |
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Definition
| opens at the genital pore through the cirrus |
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Term
| Cyclophyllidea: where is the genital pore located |
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Definition
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Term
| Cyclophyllidea: how many ovaries are there |
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Definition
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Term
| Cyclophyllidea: where does the ovary discharge into |
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Definition
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Term
| Cyclophyllidea: what canals leave the oviduct |
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Definition
| one leading to the ootype, another (vagina) leading to the genital pore |
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Term
| Cyclophyllidea: where do the vitelline glands discharge into |
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Definition
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Term
| Cyclophyllidea: what structure does the Mehlis' gland surround |
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Definition
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Term
| Cyclophyllidea: where does the ootype lead to |
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Definition
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Term
| Pseudophyllidea: scolex structure |
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Definition
| has 2 longitudinal grooves = bothria. no hooks or rostellum |
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Term
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Definition
| (sing. bothrium) 2 longitudinal suctorial grooves on the scolex |
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Term
| Pseudophyllidea: reprod organs |
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Definition
| one set per segment. uterus opens at uterine pore in the mid-line of the segment |
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Term
| Pseudophyllidea: where does the uterus open |
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Definition
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Term
| Pseudophyllidea: where is the uterine pore |
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Definition
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Term
| Cyclophyllidea: why can self fertilisation not occur |
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Definition
| b/c of protandry. cross fertilisation of segments must occur |
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Term
| Cyclophyllidea: function of the recpetaculum seminis |
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Definition
| stores sperm after they enter the vagina. |
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Term
| Cyclophyllidea: when are eggs fertilised |
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Definition
| as they pass from the ovary to the ootyp |
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Term
| Cyclophyllidea: what adds shell to the eggs |
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Definition
| vitelline and mehlis' glands |
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Term
| Cyclophyllidea: what stage passes into the uterus |
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Definition
| zygote surrounded by egg mb's - hexacanth embryo completes it's dvt in the uterus |
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Term
| Cyclophyllidea: uterus structure |
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Definition
| may be simple and tubular or branched or it may break down to form small capsules containing several eggs - dx importance |
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Term
| Cyclophyllidea: what mb's surround embryo in faeces |
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Definition
| the thin outer mb is often lost, but the embryphore still surrounds the hexacanth embryo |
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Term
| Cyclophyllidea: are eggs resistant or fragile |
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Definition
| due to the empbryophore which is highly impermeabe the eggs are very resistant. may remain viable for several years with moisture |
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Term
| Cyclophyllidea: how is the IH infected |
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Definition
| by ingesting the hexacanth embryo within the embryopore |
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Term
| Cyclophyllidea: when does hatching of the hexacanth from the embryphore occur |
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Definition
| triggered hatching - triggered by the conditions provided by the gut of the IH |
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Term
| Cyclophyllidea: what conditions trigger hatching of hexcanth (vertebrate IH) |
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Definition
| digestive enzymes break down the embryophore wall releasing the hexacanth |
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Term
| Cyclophyllidea: what activates the hexacanth once it has hatched (vertebrate IH) |
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Definition
| it is activated by bile in the SI - it burrows into the intestinal mucosa using it's 6 hooks |
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Term
| Cyclophyllidea: what does the hexacanth do once it is activated by bile in the SI (vertebrate IH) |
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Definition
| burrows into the SI mucosa and enters the portal blood stream |
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Term
| Cyclophyllidea: where does the hexacanth go once it hatches and how (vertebrate IH) |
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Definition
| it is activated by bile, burrows into intestinal mucosa, enters portal blood stream to the liver |
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Term
| Cyclophyllidea: where do they dvp (vertebrate IH) |
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Definition
| depending on spp ome dvp in liver, some in lungs, heart, mm etc |
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Term
| Cyclophyllidea: what type of DH have IH that are vertebrates |
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Definition
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Term
| Cyclophyllidea: once hatched where does the embryo go (invertebrate IH) |
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Definition
| the embryo is released in the gut, it then escapes into the body cavity/tissues |
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Term
| Cyclophyllidea: larva stage |
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Definition
|
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Term
| Cyclophyllidea: general morph of larvae |
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Definition
| cyst like structure into which is invaginated one or more tapeworm prostocolices |
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Term
| Cyclophyllidea: when are scolices of larval cyst infective to DH |
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Definition
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Term
| Cyclophyllidea: infection of DH |
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Definition
|
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Term
| Cyclophyllidea: what happens once DH ingests larval cyst |
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Definition
| The larval cyst is digested, scolex is activated by bile salts so that it evaginates and attaches to the intest wall. Strobilation then begins |
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Term
| Cyclophyllidea: what is strobilation |
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Definition
| dvt of proglottids from the neck to form the strobila. dvt continues until gravid segments are produced and the cycle is complete. |
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Term
| Cyclophyllidea: larval types |
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Definition
| cysticercus, cysticercoid, coenurus, hydatid cyst |
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Term
| Cyclophyllidea: describe cysticercus |
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Definition
| fluid filled bladder-like cyst into which ONE protoscolex is invaginated. occurs in vertebrate IH only |
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Term
| Cyclophyllidea: describe cysticercoid |
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Definition
| cyst contains no fluid and closely enfolds the ONE protoscolex. Found in invertebrate IH only (where it is too small to form a cyst) |
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Term
| Cyclophyllidea: describe coenurus |
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Definition
| fluid filled cyst lined by a germinal mb from which are budded many protoscolices (multiplication occurs). The protoscolices remain attached to the germinal layer, not grouped into capsules (as they are in hydatid cysts) only occurs in vertebrate IH |
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Term
| Cyclophyllidea: describe hydatid cysts |
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Definition
| fluid filled cyst lined by a germinal ep and bounded by a thick laminated layer. Germinal mb produces many protoscolices usually in thin walled sacs of germinal ep = brood capsules. brood capsules frquently b/c detached from the cyst lining and all to the bottom of the cyst fluid. daughter cysts may form - they have both germinal and laminated layers that form insiide and outside the original mother cyst, giving rise to brood capsules. may form hydatid sand |
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Term
| what is the sp of paramphistome in NZ |
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Definition
| Calicophoron calicophorum |
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Term
| what is the IH of Calicophoron calicophorum |
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Definition
| flat spiral shelled freshwater snail - Gyraulus corinna |
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Term
| what is the DH of Calicophoron calicophorum |
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Definition
| sheep, goats and cattle - in the reticulum and rumen |
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Term
| describe the LC of Calicophoron calicophorum |
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Definition
| miracidium infects the snail, sporocyst, redia and cercariae stages follow. excystment occurs in the SI and the young flukes migrate using their suckers thru the dd and abomasum to the rumen and reticulum (takes several weeks) |
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Term
| what is the most pathogenic phase of the Calicophoron calicophorum LC |
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Definition
| the migratory phase - causes severe gastroenteritis when several thousand flukes are migrating simultaneously. heavy infections can be fatal. |
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Term
| what stage of Calicophoron calicophorum hatches from the egg |
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Definition
|
|
Term
| what is import about the morph of Schistosoma |
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Definition
| sexes are separate - female sits permanently in the gynaecophoral groove of the male |
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|
Term
| where are Schistosoma found in the hosts |
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Definition
| invariably in BV's esp small vv of the GIT and bladder, they feed on blood. |
|
|
Term
| describe the LC of Schistosoma |
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Definition
| eggs are pushed through BV wall, and are passively F'd through tissues by mvt. some reach gut lumen or bladder and are passed out (faeces/urine), when the egg is passed, it contains a fully dvpd miracidium. egg hatches in water in response to light, miracidium invades snail IH. sporocysts produces a second generation of sporocysts then cercariae (no rediae). cerceriae have forked tail - infect DH by penetrating through skin, (no metacercarial stage). immature fluke then migrates to final site in blood stream. |
|
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Term
| how do Schistosoma cause dz |
|
Definition
1.adult flukes block small BV's
2.damage caused by passive migration of eggs through tissues stim severe inflam, fibrosis and ulceration, bleeding into lumen of affected organ.
3.severe inflam caused by eggs lodged in many tissues and organs eg.liver, brain, kidney |
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|
Term
| what parasite causes swimmers itch |
|
Definition
| cercariae of avian schistosoma invade the skin of humans causing dermatitis |
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|
