Parasites

Question 1

Ascaris suum

Answer 1

Pig nematode
Can cause mechanical damage via obstruction

An ascarid, so has 3 lips

Question 2

Ancylostoma caninum

Answer 2

Hookworm, L3 infects host by penetrating skin

Causes traumatic damage to intestinal epithelium

Question 3

Giardia

Answer 3

Protozoan

Associated with increased intestinal permeability and loss of epithelial barrier function resulting in malabsorption

Question 4

Echinococcus granulosus

Answer 4

Tape worm
Hydatid metacestode cysts
Larvae grow in large fluid-filled cyst in liver/brain/lungs/body cavities, resulting in blockage of internal organs or pressure atrophy

Definitive host is dog
Terminal host is human (would have to be eastern by dog!)

Question 5

Toxoplasma gondii

Answer 5

Protozoa
Definitive host is cat
Parastenic/transport host is mouse
Direct zoonoses cat to human

Question 6

Definitive host

Answer 6

Where adult or sexual stages of parasite develop.

Question 7

Babesia

Answer 7

Protozoa

True definitive host sexual stage in tick

Question 8

Malaria

Answer 8

Protozoa

True definitive host sexual stage in mosquito

Question 9

Intermediate host

Answer 9

Intermediate/immature/larval stages of parasite undergo development

And/OR multiply asexually

Often prey for definitive host

Question 10

Terminal host

Answer 10

Intermediate host that won’t allow transmission to definitive host

E.g. human for echinococcus granulosus

Question 11

Paratenic/transport host

Answer 11

Carries parasite to next host without multiplying/developing/increasing infectivity

Often prey for definitive host

E.g toxoplasma in mouse

Question 12

Biological vector

Answer 12

Essential to parasite lifecycle (an intermediate host)

Question 13

Mechanical vector

Answer 13

Passively carries parasite to host (e.g. on mouth parts or body)

Question 14

Cryptosporidium parvum

Answer 14

Direct zoonoses (cattle to human)

Question 15

Leishmania infantum

Answer 15

Indirect zoonoses (dog, sandfly, human)

Sandfly is biological vector (developed and replicates there)

Has 2 morphological distinct forms (promastigote and amastigote)

Question 16

Ostertagia ostertagi

Answer 16

Nematode of cattle with direct life cycle (cattle is only host)

Separate sexes, females lay eggs which pass in faeces
Eggs hatch in environment and undergo 4 moults, L3 infectious, L5 final immature adult

Question 17

Fasciola hepatica

Answer 17

Trematode of sheep and cattle with indirect life cycle

Definitive host ingests infected snail

Question 18

Dicrocoelium dendriticum

Answer 18

Primary host snail
Secondary host ant (consumes sugary slime balls from snail)
Ant CNS infected and spastic paralysis prevents ant leaving grass plates

Question 19

Diphyllobotrium latum

Answer 19

First host crustacean
Secondary host fish
3rd host predatory fish
4th host human

Question 20

Haemonchus contortus

Answer 20

Sheep nematode

Question 21

Eimeria ovinoidalis

Answer 21

Sheep protozoan

Question 22

Strongylus

Answer 22

Large mouth nematode which leads to buccaneers capsule

Question 23

Pre-patent period

Answer 23

Time between infection and detectable evidence of the parasite (e.g eggs/cysts/larvae in faeces, or parasites in blood)

Question 24

Dirofilaria immitis

Answer 24

Nematode in blood

Question 25

Toxocara canis

Answer 25

Ascarid nematode Host infected by ingesting egg containing larvae Hepatic-tracheal migratory lifecycle (gut portal vv liver hepatic v cd VC heart pulmonary a lungs bronchi trachea oesophagus gut)

Question 26

Dipylidium caninum

Answer 26

Cysticercoid Cestoda | Small intermediate arthropod host

Question 27

Cysticercoid

Answer 27

``` Metacestode 1 evaginated scolex Small solid cyst Normally I’m very small arthropod intermediate host E.g dipylidium caninum ```

Question 28

Hydatid

Answer 28

``` Metacestode Large fluid filled cyst lined with germinal epithelium Invaginate scolices Hydatid sand contents Occasional daughter cysts ```

Question 29

Taenia solium

Answer 29

Tapeworm | Cysticercus metacestode

Question 30

Multiceps multiceps

Answer 30

Cestoda with coenerus metacestode

Question 31

Taenia taeniaformis

Answer 31

Cestoda with strobilocercus metacestode

Question 32

Strobilocercus

Answer 32

Metacestode Evaginated scolex Asexual proglottids

Question 33

Coenurus

Answer 33

Metacestode Fluid-filled cyst Several invaginate scolices

Question 34

Ostertagia ostertagi

Answer 34

Most economically important GI nematode in cattle causing PGE A.k.a brown stomach worm Forms type 1 and type 2 disease L3s exsheath in rumen and then develops in abomasal glands to form L5. Adults mature on mucosal surface. Abomasal glands collesce to form morrocon leather appearance in severe infections PPP 3 wk (up to 6mo if hypobiosis)

Question 35

Type 1 disease of PGE in cattle

Answer 35

Calves affected when grazed intensively in first season Ingest many L3s on pasture which become adults 3-4wks later. Disease seen mid-July - Oct >75% morbidity but low mortality if treated promptly

Question 36

Type 2 disease of PGE in cattle

Answer 36

Affects yearlings Following first grazing season, usually late winter. Caused by maturation of hypobiotic EL4s injested in autumn. Mature in late winter/early spring Low no. Affected, a few individuals, but high mortality

Question 37

PGE clinical signs

Answer 37

Profuse watery diarrhoea Weight loss (up to 20% in 7-10d) Inappetant

Question 38

Teladosagia

Answer 38

Sheep PGE | Similar epidemiology to cattle ostertagia ostertagi

Question 39

4 epidemiology features of PGE cattle

Answer 39

1) many L3s survive winter on pasture (if sufficient can cause type 1 disease) 2) high mortality of overwontered L3s in spring (pasture safe after mid summer) 3) eggs deposited in aping slow to develope (Laos in April/May L3 by mid July onwards) 4) autumn low temp causes up to 80% of ingested L3s to be inhibited at EL4 (May mature overwinter and early spring to give type 2 disease)

Question 40

Abomasal adult nematode location in cattle

Answer 40

2 of note Ostertagia ostertagi Haemonchus placei

Question 41

Small intestine location of adult nematode cattle

Answer 41

1 of note Nematodarius spp.

Question 42

Benzimadazoles, levamisole, avermectins/milbemycins Treat whic disease

Answer 42

Type 1 and 2 ostertagia ostertagi

Question 43

4 control options for PGE cattle

Answer 43

1) prophylactic anthelmintics (between turn out and mid July) 3wk intervals 2) dose and move Anthelmintic early July and immediately move But warning, L3s can overwinter on first pasture 3) rotate grazing young and adult (calves first, then immune adults) 4) alternate grazing cattle/sheep/crops