Helmintology Flashcards
Nowadays we have started to use Praziquantel in horse deworming. Why is that? (?)
Because Amitraz is not useful
Parasites effecting the Cow’s eye:
Thelaziosis
Onchocercosis
Eye disease in grazing Horse via nematodes:
- L3 of Draschia megastoma
- Adults of Thelazia lacrymalis
- Microfilariae of Onchocerca cervicalis
- Microfilariae of Setaria equine
Skin surface migration in humans called:
Cutaneous larva migrans – Parasitic worm infection caused by hookworm larvae
They belong to the phylum of Flatworms:
Trematodes (flukes) and Cestodes (tapeworms)
Which is not related to the others?
Cercaria
Related: Procercoid, Plerocercoid, Cysticercoid
Developmental phases of Flukes:
Usually 5 stages – Egg - MI – SPO – RE – CE (- Adult)
At least how many larval stages do the Flukes have?
5
General life-cycle of Trematodes:
Egg - Discharged either in open water or in intestine of definitive host.
Miracidium (plural miracidia) - A free-living motile form, it is covered with cilia, and settles in the mollusc to become a sporocyst.
Sporocyst - An elongated sac, it produces either rediae or more sporocysts.
Redia (plural rediae) - A larval form with an oral sucker, it will produce either more
rediae, or cercariae.
Cercaria (plural cercariae) - The larval form of the parasite, it develops within the germinal cells of the sporocyst or redia. A cercaria has a tapering head with large penetration glands. It may or may not have a long swimming “tail”, depending on the species. The motile cercaria finds and settles in a host where it will become either an adult, or a mesocercaria, or a metacercaria, according to species.
Mesocercaria - A cercaria little modified but resting.
Metacercaria - A cercaria encysted and resting.
Cercaria is also used as a genus of trematodes, when adult forms are not known.
Adult - The fully developed mature stage, it is capable of sexual reproduction.
Which developmental form comes after MIracidium?
SPOrocyst
This larval stage follows the REdia stage:
CErcaria
Larva leaving intermediate host:
CErcaria
What occurs after Metacercariae?
Adult
It can occur in the environment:
Metacercaria
Which Flukes don’t occur in the intestines?
- F. hepatica
- D. dendriticum
- Paramphistomum spp.
Fluke in small intestine: A. alaria
Trematode (Flukes) egg can be detected via:
FEC Faecal Egg Count in Paramphistomum – Chronic form, Dicrocoeliosis, Schistosoma
except Fasciola hepatica, F. gigantica, Paramphistomum spp. acute form
Drug to use against Flukes?
- Liver flukes - Triclabendazole – Only fluicide which shows 90-100% efficacy against both early immature and mature Fasciola spp.
- Rumen fluke – Niclosamide (acute form – against immature intestinal stages) and Levamizol, Oxikolzanid (chronic form – adult flukes are more difficult to remove)
- Blood flukes – Praziquantel – Young flukes are less sensitive.
- Alaria flukes – Praziquantel
What is not effective against Flukes?
Ivermectin
Effective against flukes: Triclabendazole, Albendazole, Praziquantel
Liver fluke development:
MIS → SPOR → RE1 → RE2 → CE
Which is the intermediate host of Fasciola hepatica (the common liver fluke)?
Galba truncatula snail, in Europe only. Parentenic host is cattle.
Hosts of F. hepatica:
Wide. Most herbivorous mammals and humans.
Susceptible for Liver fluke:
Goat, sheep, cattle, etc.
This/ These animals has/ have low resistance against F. hepatica: MCQ
- Rabbit, Sheep, Goat (also mouse, rat)
- Delayed resistance – Humans
- Early resistance – Horse, pig, dog, cat
F. hepatica location:
Bile ducts (location where they turn into adults)
Large American liver fluke:
Fasciola magna – Large American liver fluke, giant liver fluke, deer fluke
Which is the intermediate host of the Great American fluke?
Galba truncatula snail. Parentenic host is cattle (no eggs in faeces).
F. magna egg size:
110-160 um with zygote
Deer is the host of which fluke?
F. magna /American liver fluke
Choose the right statement:
F. Magna can’t complete its life cycle in small ruminants
In which species is F.magna incapsulated?
Deer, cattle – Flukes are encapsulated in the liver by host reaction and are less pathogenic
Small ruminants’ fatal death can be caused by:
F. magna – In sheep and goats, worms may migrate constantly in the liver tissue causing traumatic hepatitis which is fatal – Affected sheep usually die within 6 months.
Which species lives in a capsule in the liver?
F. magna
Which fluke causes caverns in the liver?
F. magna
It feeds through the body surface too: (?)
Fasciola gigantica (the large liver fluke)
Drug to use against Liver flukes?
Liver flukes - Triclabendazole – Only fluicide which shows 90-100% efficacy against both early immature and mature Fasciola spp.
Rumen fluke development:
MI → SPO → RE → CE
What is not absolutely necessary in the life-cycle of the Rumen fluke?
→ 2 intermediate hosts.
Rumen flukes have an indirect life cycle via freshwater OR amphibious snails as
intermediate hosts.
How can you diagnose acute Paramphistomosis?
Necropsy – microscopical examination (since no eggs in acute form, but can do FEC in chronic form)
What is the larval stage that develops in Dicroceolium in ants?
Metecercaria
Schistosoma, Dicrocoelium development:
MI → SPO1 → SPO2 → CE
How many intermediate hosts does Lanceolote fluke have?
2 intermediate hosts – Terrestrial snails and Ants
Dicrocoeliosis is:
Zoonotic!!
Schistosoma, Dicrocoelium development:
MI → SPO1 → SPO2 → CE
Eggs are spiny, contain Miracidium when passed out in urine or faeces.
Cercariae – Only Furocercaria (infective stage)
Where in the world is S. mansoni found?
Tropical Africa and South America – Tropical and Sub-tropical zones
Which Schistoma species can be found in bladder?
S. mansoni (bladder schistosomosis)
S. haematobium ( urinary or bladder schistosomosis)
Blood fluke infects host by:
Penetrating skin – Cercariae penetrate skin, rash develops – Called schistosome or simmer’s itch.
What is the name of the infective stage of Blood flukes:
Furocercariae
Infection – Percutan or Per os
How do offspring of Blood flukes get out from final host?
Eggs
Eggs are spiny, contain Miracidium when passed out in urine or faeces.
Which developmental stages of Blood fluke occur in snail?
Spor and Cer
Blood fluke infection from what?
Urine and faeces – Contain eggs with miracidium
This parasite do not have metacercaria?
Blood-fluke
Number of intermediate hosts in Alaria alata?
Two intermediate hosts – Snails (Helisoma spp.) and Tadpoles mesocercaria / Frogs
Alaria alata in Paratenic hosts:
Mesocercariae – Wild boar, pig, poultry, humans (lung, eye) – Adults in small intestine
Which Flukes don’t occur in the intestines?
- F. hepatica
- D. dendriticum
- Paramphistomum spp.
Fluke in small intestine: A. alaria
Where is Alaria alata? (flatworm)
Final hosts - Dog, cat Parentenic hosts (=transport hosts) - Pig, poultry, humans. Small intestine
Phylum: Platyhelminthes (Flatworms) – Class Cestoda (Tapeworm)
→ No sexual dimorphism.
→ Life cycle of tapeworms is indirect with one intermediate host, except for Order Pseudophyllidae (Family Diphyllobothriidae).
→ Eggs contain L1 (6-hooked oncosphere) except for D. latum (zygote).
→ Infection per os with L2 except for D. latum (L3)
→ Adults live in small intestine.
→ Cestodoses Infections caused by adults.
→ Metacestodes Infections caused by larvae in intermediate hosts
They belong to the phylum of Flatworms:
Trematodes (flukes) and Cestodes (tapeworms)
Proglottids are produced by:
Cestoda
What is true about scolex in Cestoda only?
For attachment
They have no digestive tract:
Cestodes
Diphyllobothriosis does not occur in:
Sheep
It occurs in humans and animals eating fresh-water fish (dog, cat, pig, fox).
Species not effected by Diphylobathrum latum?
Cattle
Life cycle of Diphyllobothrium:
Indirect life cycle – 2 intermediate hosts; Crustaceans and Freshwater fish
Egg – Coracdiudm (L1) – Procercoid (L2) in Curstaceans – Plerocercoid (L3) in Freshwater fish
Diphyllobothrium causes:
Anemia, vitamin B12 deficiency
How does Diphylobotrum latum infect?
Per os – Via fish intake
How can a human be infected with Diphyllobothrium latum (broad tapeworm)?
Ingestion of fish
Human can be infected by eating infected meat including:
Diphylobothrium latum (Human broad tapeworm)
Meat borne infection of human is/are: MCQ
Diphylobotriosis
Pork measle
What is inside the ovum of the Diphyllobotrium?
Zygote
Diphillobotrium have:
Yellow, oval egg with zygote inside.
The offspring of the Broad Tapeworm is shed by the host in which form?
Egg
Tapeworm of Ruminants:
- Indirect life cycle
- Intermediate host – Box mites (Oribatidae)
- Eggs (with 6 hooked oncosphere) → Cysticercoid L2
Worm which looks like grains of cooked rice in faeces in Sheep:
Monezia expansa
Moniezia spp. FEC with flotation:
- M. expansa – Triangular egg
- M. benedeni – Quadrangular egg
It ́s larvae are not hepatophilic:
Echinococcus granulosus
The infective stage of Echinoccocus granulosus is:
Hyatid cyst
Cystic echinococcosis / Hydatidosis / Hydatid disease:
- One of the most important parasitic zoonoses.
- Caused by Echinococcus hydatidosus, the infective L2 of E. granulosus. Intermediate host include ruminants, equine, pig, humans.
Infective stage of Echinococcus granulosus in Humans:
G1 (from sheep)
G2 (T sheep)
Dosage of Praziquantel against E. granulosus:
5mg/kg
Treatment against Echinococcus spp. in Dogs:
Praziquantel – 5 mg/kg
Epsiprantel – 7.5 mg/kg
100% efficacy against adults and immature forms!
Ecchinococcus multilocularis can occur in humans:
Never
E. multilocularis final host is Dog (rarely cats).
Its larva, E. alveolaris occurs in rodents and humans’ livers.
Can Cat be infected with E. multilocularis?
True (rarely)
How many proglottids does Diphyllidium caninum have?
Many. In gravid segment, cocoon present (with 3-30 eggs)
Epidemiology – Occupational infection of Dogs:
→ Hunting Dog - Taenia pisiformis (since larvae located in rabbit, hare)
→ Butcher’s Dog ungulates)- Taenia hydatigena, E. granulosus (since larvae located in ungulates
→ Shepherd Dog - Taenia multiceps (since larvae located in Ruminants)
→Dog around Pigs - E. granulosus (since larvae located in Swine)
Dipylidium caninum can cause visceralis larva migrans in Human:
False
What is the name of the most common tapeworm in Horses?
Anoplocephela perfoliata
Life cycle of Anoplochephala:
Indirect. Cysticercoid (L2) in box mites (Oribatid mites)
In small and large intestine. A. perfoliata tend to congregate at ileo-caecal junction.
What do we diagnose with Proudman method (FEC type)?
Anoplochepala perfoliata
Moxidectin isn’t good against:
Anoplocephala
Moxidectin only against Strongyloides
Praziquantel, Pyrantel embonate, Niclosamide against Horse tapeworm.
Which tapeworm spp. can cause auto-infection in humans?
- Taenia solium – via Cysticercus cellulosae (infective L2)
- Taenia saginata – via Cysticercus bovis (infective L2)
- Taenia asciatica
- Diphylobothrum latum
Found in the brain:
Cysticercus cellulosae in Human and pig brain, muscles, heart, eyes
The tapeworms belong to:
Platyhelminthes
Life-cycle of Tapeworms:
Indirect
Which domestic animal doesn’t have a specific Tapeworm species?
Swine
Larva Forms (L2):
→ Cysticeroid - Invertebrates. 1 worm develops in definitive host → Strobilocercus - 1 worm → Cysticercus - 1 OR many worms → Echinococcus - Many worms → Coenurus - Many worms
From which do only one tapeworm develop?
Cysticercoid and Stobilocercus (and Plerocercoid ?)
Many adult tapeworms develop from this type of larva:
Echinococcus and Coenurus
It occurs in vertebrate intermediate host:
Plerocercoid – Usually occurring in muscle of fish.
Only one protoscolex develops from:
Strobilocercus
This larva is not able to reproduce asexually in the host:
Cysticercus
It can develop asexually:
Sporocyst
If meat infected:
Must be discarded immediately.
Intermediate host of Taenia pisiformis?
Rabbits
What is found in muscle?
- Cysticercus cervi
- Coenurus serialis
- Cysticercus cellulosae
- Cysticercus bovis
Which are hepatophilic (=migrate in liver parenchyma)? MCQ (correct, from notes)
→ Taenia hydatigena (has infective L2 Cysticercus tenuicollis) - Juvenile worm is hepatophilic
→ Taenia piriformis (has infective L2 Cysticercus piriformis) - Larvae are hepatophilic
The following statement is correct:
Hepatophilic tapeworm larva develops to L2
Which is not hepatophilic:
T. longicollis, E. granulosus Hepatophilic: T. Psiformis, E.alveolata Are hepatophlic (notes): Juvenile worms, larvae
Beef measles:
- Cysticercus bovis in cattle commonly called bladder worm or beef measles.
- Caused by Cysticercus bovis; the infective L2 of the human tapeworm Taenia saginata
Carcass unfit for consumption:
If 2 or more living cysts are found at more than 1 inspected site.
Pork measles:
Carcass damage when tapeworms are encysted in meat.
Caused by Cysticercus cellulosae; the infective L2 of the human pork tapeworm, Taenia solium
Larva of Taenia hydatigena:
Is hepatophilic
The intermediate hosts of T. pisiformis are:
Rabbit, hare
What is the host sp. of Taenia ovis?
dog
Cysticercus tennuicollis is the L2 that develops to T. Ovis
False
Cysticercus ovis → Taenia ovis
Cysticercus tennuicollis → Taenia hydatigena
How many worms can come from Cysticercus tenuicollis? (?)
One worm b) Two worms c) Many worms d) None
Cysticercus - 1 OR many worms
Cysticercus ovis effects which organs?
Muscle, heart
Which one doesn’t occur in muscle?
Cysticercus pisiformis, C. tenuicollis
Both occur in liver and mesentery.
How many protoscolices are in Cysticercus piriformis?
one
Tapeworm whose metacestode is C. cellulosae?
Taenia solium
Ecchinococcus hydatidiosus is L3:
False – It is L2 (infective stage)
Whats the name of tapeworm sp. of red foxes which causes severe infection in Hu?
Echinococcus multilocularis – Scientific name of fox tapeworm (Careful! E. alveolaris also as a choice, but this is the infective larva)
It occurs in invertebrate intermediate host:
Cysticercoid
‘Hepatitis cysticercosa’ caused by:
Cysticercus tenuicollis Cysticercus pisiformis
The infective stage of Taenia solium can develop in?
Humans and Pigs
Graphidium strigosum location:
Stomach of rabbit
This infection can be detected by inspecting faeces with floatation method: MCQ
Spirocercosis Trichostrongylus
It lives in the large intestine of Ruminants: MCQ
Chabertia ovina – Colon and rectum
Oesaphgstomum dentatum – Caecum and colon (Ruminants – Also ileum)
Which one has a smooth surface?
Toxascaris leonina
PE-2 of this/these species isn’t ascaroid type:
→ A. galli and T. leonina – Ascaridoid type
A. suum and P. equorum – Asacaroid type
Galactogenic infection related to what type migration?
Toxocaroid type
Hypobiotic larvae – Prenatal (intra-uterine) and lactogenic routes of infection of new- born animals.
Which one has earthworm as intermediate host:
Other
→ Lungworms of Pig (Metastrongylus apri, M. pudendotectus, M. salmi) → → Nematode of Dog (Capillaria plica, C. annulata, C. caudinflata, C. bursata)
Hyostrongylus rubidus location:
Stomach – Gastric mucosa. Pigs
Which lives in the stomach of Swine?
H. rubidus – Red stomach worm
Hyostrongylus causes:
→ Larvae – Hypertrophic, ulcerative, acute gastritis – Blood in the gastric lumen → Adult Worms – Chronic catarrhal gastritis, gastric ulceration.
Hyostrongylus rubidus vs. Oesophagmatum. The eggs can be differentiated:
false
It is easy to distinguish the eggs of H. rubidus and Oesophagostomum:
false
Oesophagstomum eggs (strongyle-type eggs) are hard to distinguish from:
Hysostrongylus eggs (stomach worm)
Hyostrongylus detection:
FEC – Strongyle type eggs – Not distinguishable from the eggs of Oesophagostomum. Necropsy – Red worms, mucosa of stomach is thickened, lenticular, flat nodules. Disease history
What is the infective stage of Amidostomosis?
L3 – Egg → L3 hatches, survives in shallow water
It occurs in the gizzard of ducks and birds:
Amidostomum anseris
What can be detected in living birds infected with Amidostomum spp.?
Eggs from faeces
How does Amidostomum infect?
→ Per os and Per cutan
→ Infection orally with water. In goslings, by penetrating through the web.
It does not have extra-intestinal migration:
Amidostomum anseris
What is the name of Cat Stomach worm?
Ollulanus tricuspis
Hosts of Ollulanosis:
Cat, wild cat, other felids. Occasionally dog, fox, pig.
How does the Cat get infected by Stomach worm?
Ingestion of vomit
What is the route of infection with Stomach worm of Cat?
Ingesting of vomit of infected cat containing L3 – Larvae do not pass out with faeces
What is the infective stage of Cat Stomach worm?
L3
What is laid by the female Stomach worm of Cat?
L3 – Female is viviparous, eggs develop to L3 ‘in utero’
What is the name of the infective stage of the Cat’s Stomach worm which spread(s) from animals to animals?
L3 – Become adults on the gastric mucosa by 5 weeks PI (auto-infection)