ANSWERS

1. What is an endoparasite?
   A parasite living within the body of its host.
2. What are the 2 main subgroups of endoparasites?
   • Helminths (worms and flukes).
   • Protozoal parasites (small, unicellular organisms).
3. What are the 2 main groups of intestinal worm?
   • Cestodes - tapeworm.
   • Nematodes - roundworm.
4. State the 2 main differences between cestodes and nematodes.
   • Cestodes have no alimentary tract, whilst nematodes possess a proper digestive tract.
   • Cestodes have an indirect life cycle and are dependent upon intermediate hosts, whilst nematodes predominantly possess a direct life cycle (with the exception of lungworm - in which the slug or snail is the intermediate host, and others which may be carried by a parantenic host).
5. Name the 3 main components which make up the tapeworm.
   • Scolex - the head.
   • Rostellum - a protusible cone armed with hooks (present in some species).
   • Strobila - a chain of segments (known singly as proglottids) which make up the "body" of the worm.
6. What is the general name given to immature tapeworm?
   Metacestodes.
7. List the 3 main types of tapeworm.
   • Dipylidium caninum.
   • Taenia spp.
   • Echinococcus granulosus.
8. What is the difference between a cysticercus, a cysticercoid and a coenurus?
   • Cysticercus - a fluid filled cyst containing a single invaginated scolex attached to the cyst wall.
   • Cysticercoid - a fluid filled cyst containing a single evaginated scolex (found in invertebrate intermediate hosts).
   • Coenurus - a fluid filled cyst containing many invaginated scolexes attached to the cyst wall.
9. What is the most common tapeworm of cats and dogs in the UK?
   Dipylidium caninum.
10. What is the intermediate host of Dipylidium caninum?
    The flea (or biting louse in dogs).
11. Which zoonotic disease is associated with Echinococcus granulosus?
    Hydatid disease.
12. Which tapeworm is associated with eating uncooked meat, and why might this be particularly difficult to control?
    Taenia spp. It is difficult to control in scavenging animals and those that capture wild prey.
13. List anthelmintics suitable for the treatment of cestode infestation.
    • Milbemax tablets - Milbemycin oxime, Praziquantel - effective against Dipylidium caninum, Taenia spp., Echinococcus multilocularis and Echinococcus granulosus in dogs; Dipylidium caninum, Taenia spp. and Echinococcus multilocularis in cats.
    • Droncit injectable/Droncit tablets - Praziquantel - effective against all tapeworm species and licensed for use in cats and dogs.
    • Drontal Cat tablets - Praziquantel, Pyrantel embonate - effective against Dipylidium caninum and Taenia spp., licensed for use in cats.
    • Drontal Plus tablets - Praziquantel, Pyrantel embonate, Febantel - effective against all tapeworm species, licensed for use in dogs.
    • Lopatol tablets - Nitroscanate - effective against Dipylidium caninum and Taenia spp., licensed for use in dogs.
    • Panacur liquid/paste - Fenbendazole - effective against Taenia spp., licensed for use in dogs and cats and is used in other species including tortoises.
    • Telmin tablets - Mebendazole - effective against Taenia spp. And Echinococcus granulosus, licensed for use in cats and dogs.
    • Troscan tablets - Nitroscanate - effective against all tapeworm species, licensed for use in dogs.
      Some of the wormers listed above are also effective against all or some of the roundworm species; please also refer to Q30.
14. List the 6 groups of nematodes and give examples of each.
    • Ascarids - Toxocara canis, Toxocaris leonina, Toxocara cati.
    • Bladder/liver worms - Capillaria spp.
    • Heartworm - Dirofilaria immitis.
    • Hookworms - Uncinaria stenocephala, Ancylostoma caninum.
    • Lungworms - Aelurostrongylus abstrusus, Angiostrongylus vasorum, Oslerus osleri.
    • Whipworm - Trichuris vulpis.
15. What is a paratenic host?
    A species that is not the normal host for a parasite but that may be used opportunistically by the parasite. It acts as a carrier only, and no development of the parasite occurs within this host. (Paratenic hosts must be eaten in order to pass on infection). An example is Toxoplasma gondii responsible for toxoplasmosis.
16. What is a transport host?
    A host able to pass infection to other susceptible hosts at any time. The transport host remains unaffected and acts to maintain viability of the microorganism and pass infection directly to another animal. An example is the flea which is the transport host of Haemobartonella felis.
17. What is a final/definitive host?
    One that harbours the parasite during its adult sexual stage.
18. What is an intermediate host?
    One that shelters the parasite during a non-reproductive stage of its life cycle.
19. Name the 2 zoonotic diseases associated with Toxocara canis.
    • Toxocariasis.
    • Visceral larval migrans.
20. Name 2 types of hookworm. Which of these is associated with greyhounds or hunt kennels?
    • Uncinaria stenocephala (Northern hookworm) - This is the hookworm associated with greyhounds or hunt kennels.
    • Ancylostoma caninum.
21. Which nematode is associated with pedal dermatitis in dogs with permanent access to grass runs?
    Trichuris vulpis.
22. What is Dirofilaria immitis commonly known as?
    Heartworm. This species does not occur in the UK, but may be seen in imported animals.
23. Which nematode often manifests symptoms of coughing?
    Lungworms (Aelurostrongylus abstrusus - cat lungworm, Angiostrongylus vasorum, Oslerus osleri).
24. What is the name of the diagnostic test used to detect the presence of lungworm larvae?
    The Bauermann technique.
25. What organs are affected by the Capillaria species?
    • The bladder - Capillaria plica.
    • The liver - Capillaria hepatica.
26. What are the 2 main techniques used to confirm a diagnosis of nematode infestation?
    • Modified McMaster techniques - for detection and identification of worm eggs.
    • The Bauermann technique - for detection of worm larvae.
27. Why are faecal flotation methods unsuitable for the identification of cestode ova?
    Faecal floatation methods involve the use of a saturated salt solution upon which nematode ova float. Cestode ova sink, and therefore cannot be detected with such techniques.
28. List 5 protozoal parasites.
    • Coccidia.
    • Giardia.
    • Hammondia.
    • Isopora.
    • Toxoplasma gondii.
29. List 6 precautions that may prevent the spread of zoonotic diseases caused by helminths.
    • Ensure regular worming with effective, licensed veterinary products.
    • Ensure that children always wash their hands before eating and discourage them from sucking dirty fingers.
    • Be sure that floors where children play are clean.
    • Never leave young children unsupervised with a pet.
    • Always clear up pet faeces immediately, especially in public places and ensure that you wash your hands afterwards.
    • Train cats to use a litter tray and ensure that regular cleaning and disinfection is undertaken.
30. List anthelmintics suitable for the control of nematodes in domestic cats and dogs.
    • Milbemax tablets - Milbemycin oxime, Praziquantel - effective against Toxocara canis, Toxascaris leonina, Ancylostoma caninum, Trichuris vulpis, Dirofilaria immitis in dogs;Toxocara cati and Ancylostoma tubaeforme in cats.
    • Program Plus - lufenuron and milbemycin oxime - effective against Toxocara canis, Ancylostoma caninum, Trichuris vulpis, Dirofilaria immitis and fleas. Licensed for use in dogs.
    • Canovel tablets - Piperazine phosphate - effective against Toxocara canis/cati, Ancylostoma caninum and Uncinaria stenocephala, licensed for use in dogs.
    • Catovel tablets - Piperazine phosphate - effective against the species listed above, licensed for use in cats.
    • Citrazine tablets - Piperazine citrate - effective against the species listed above, licensed for use in cats and dogs.
    • Drontal Cat tablets - Praziquantel, Pyrantel embonate - effective against Toxocara canis/cati, licensed for use in cats.
    • Drontal Plus tablets - Praziquantel, Pyrantel embonate, Febantel - effective against Toxocara canis/cati, Ancylostoma caninum, Uncinaria stenocephala and Trichuris vulpis, licensed for use in dogs.
    • Endorid tablets - Piperazine phosphate - effective against Toxocara canis/cati, Ancylostoma caninum and Uncinaria stenocephala, licensed for use in cats and dogs.
    • Lopatol tablets - Nitroscanate - Effective against the species listed above, licensed for use in dogs.
    • Panacur liquid/paste - Fenbendazole - Effective against the species listed above plus Trichuris vulpis, licensed for use in cats and dogs.
    • Piperazine Citrate tablets - Piperazine citrate - Effective against those species listed for Lopatol, licensed for use in cats and dogs.
    • Strongid paste - Pyrantel - Effective against those species listed for Lopatol, licensed for use in dogs.
    • Telmin tablets - Mebendazole - Effective against Toxocara canis/cati, Ancylostoma caninum, Uncinaria stenocephala and Trichuris vulpis, licensed for use in cats and dogs.
    • Troscan tablets - Nitroscanate - Effective against Toxocara canis/cati, Ancylostoma caninum and Uncinaria stenocephala, licensed for use in dogs.
      Some of the wormers listed above are also effective against all or some of the tapeworm species; please also refer to Q13.
31. How frequently should domestic cats and dogs be wormed?
    As a general guideline - every 3 months is recommended. However, monthly worming is required to be certain of keeping an animal free of T.canis, since the prepatent period is only 5-6 weeks. More frequent worming is also recommended if the animal lives with young children, hunts or scavenges. As with all medicinal products, though, the manufacturer's instructions for use should be followed.