Parasitology Flashcards
1
Q
Define Endoparasite
A
a parasite that lives within the host
2
Q
Define Ectoparasite
A
a parasite that lives on/outside the host
3
Q
Define Definitive Host
A
primary host in which the parasite reaches maturity and sexually reproduces
4
Q
Define Intermediate host
A
secondary host In which the parasite undergoes some stage or stages of development, but does not sexually reproduce
5
Q
Define a temporary parasite
A
the parasite does not live on/in the animal for its entire life cycle
6
Q
What are the 4 main groups of endoparasite in UK?
A
- Nematode (round worm)
- Cestode (flattened tapeworm)
- Trematode (flukes)
- Protozoa (single-celled organism)
7
Q
Describe the appearance of nematodes
A
Round in cross section
Either male or female worm
One whole organism
8
Q
What are 5 main types of nematode?
A
Ascarids Hookworms Whipworms Lungworms Heartworms
9
Q
Name the ascarid that infects dogs
A
Toxocara canis
10
Q
Describe the appearance of Toxocara canis
A
long and off-white in colour
look like beansprouts
11
Q
What are the clinical signs of a dog with a Toxocara canis infection?
A
Distended belly
Stunted growth
puppies may also have vomiting or diarrhoea
12
Q
Describe the life cycle of Toxocara canis?
A
Eggs are laid by females and passed in the faeces.
Infective egg is found on the ground in the environment.
The egg can the either be:
1. eaten by a human
2.eaten directly by a puppy. The larvae migrate from the intestine to the liver and lungs, coughed up and swallowed. Mature to adult worms in the SI.
3. eaten by a paratenic host (e.g. rat) and the pup becomes infected by eating the paratenic host.
4. Eaten by an adult dog. The larvae migrate from the intestine to resting sites in the tissues.
In pregnant bitches, the larvae will migrate from the intestine across the placenta about the 42nd day of pregnancy - the pups are infected prenatally. The larvae migrate from the intestine to the liver and lungs, coughed up swallowed and mature to adult worms in the SI.
Also the larvae in the resting sites of the adult dog can migrate to the mammary glands and infect the pups via milk - there is no larval migration in the pups and the worms mature in the intestine.
13
Q
How can we prevent Toxocara canis infections in puppies?
A
Owner education
Treatment of bitch before she gives birth
can treat puppies with anthelmintics from 2wks old
Clean/treat environment
14
Q
What ascarid nematode infects cats?
A
Toxocara cati
15
Q
Describe the appearance of T cati
A
Very similar to T canis, but the anterior end looks like an arrowhead
16
Q
What is the prepatent period of T cati?
A
8 weeks
17
Q
Describe the life cycle of T cati (in comparison to the life cycle of T canis)
A
Very similar - difference is that there is no prenatal migration of larvae across the placenta so the kittens first acquire infection from the queen’s milk.
18
Q
What are the clinical signs of kittens infected with T cati?
A
stunted growth
pot bellies
19
Q
When can kittens be treated for T cati
A
from 3 weeks of age
20
Q
What is the ascaris nematode that infects both dogs and cats?
A
Toxascaris leonina
21
Q
What is the difference in its life cycle compared to that of T canis and T cati?
A
Animals are only infected by ingesting the eggs themselves or an infected paratenic host
22
Q
When would you see a patent infection of T leonina in cats and dogs?
A
From about 3 months of age or older
23
Q
What is the prepatent period of T leonina?
A
8 weeks In dogs and 13 weeks in cats
24
Q
What are the clinical signs of T leonina?
A
usually No clinical signs
Large numbers of worms are well-tolerated
25
How can the eggs of T leonina be differentiated from the others?
Very smooth, thick walled egg
26
Name (and spell!) 3 types of Hookworm and what hosts they affect
1. Uncinaria stenocephala - dogs and rarely cats
2. Ancylostoma caninum - dogs and rarely cats
3. Ancylostoma tubaeforme - cats (in Europe)
27
How can Uncinaria stenocephala be identified?
Has plates in the mouth as opposed to hooks
| - commonly found in like racing kennels etc
28
Describe the life cycle of Uncinaria stenocephala
Eggs are passed in the faeces, larvae develop in the egg, 1st stage larvae are liberated from the shell, develop into 3rd stage infective larvae in the environment and then eaten by the dog.
29
What is the prepatent period of Uncinaria stenocephala?
3 weeks
30
What is the distinct difference between the plated Uncinaria stenocephala and the other two 'hooked' hookworms?
Uncinaria stenocephala can penetrate the skin but will only cause local dermatitis, unlike other species of hookworm that can penetrate both the skin and migrate to the intestine.
31
What are the clinical signs of a dog with a heavy infection of Uncinaria stenocephala?
Can have anaemia, diarrhoea and intestinal protein loss
32
How can Ancylostoma caninum be identified?
3 sets of hooks in the mouth (used to attach to the intestine)
33
How can dogs become infected with Ancylostoma caninum?
By either penetration of the skin or by ingesting infective larvae.
34
Describe the life cycle of Ancylostoma caninum
Eggs passed in the faeces.
Larvae develop within the egg.
1st stage larvae are liberated from the shell.
Develop into 3rd stage infective larvae (occurs quicker in hotter climates).
Eaten by dog or penetrate the skin.
Immature larvae remain in tissues, migrate to mammary glands and infect the pups via the milk.
Others develop into adult worms in the intestine.
35
What Is the prepatent period of Ancylostoma caninum?
3 weeks
36
What are the clinical signs of Ancylostoma caninum?
Heavy infection can result in anaemia.
| Not all blood is consumed by worms so some can be seen in the faeces (melena)
37
What hookworm is found in European Cats?
Ancylostoma tubaeforme
38
Briefly describe Ancylostoma tubaeforme
2 pairs of 3 teeth at entrance to mouth. Can cause anaemia with heavy presence or a small chronic infection
39
Name (and spell!) a whipworm found in dogs
Trichuris vulpis
40
Describe the identification of Trichuris vulpis
Characteristic whip-like tail and thick 'handle' end. Uses its tail to anchor to the intestinal wall and the thick part hangs out into the lumen.
41
Describe the life cycle of Trichuris vulpis
Eggs are passed in the faeces and embryonate in the environment. Larvae remain in the shell once developed.
The eggs have thick walls so can survive in the environment for long periods of time (therefore a substantial infection can accumulate in kennels etc)
42
What are the clinical signs of dog infected with Trichuris vulpis?
Weight loss
| Blood and mucous-filled diarrhoea
43
How can Trichuris vulpis be treated?
Suitable anthelmintic and move animals away from infected area
44
Name the main lungworm of cats
Aelurostrongylus abstrusus
45
Briefly Describe the life cycle of Aelurostrongylus abstrusus
Indirect life cycle
Cats can become infected by eating infected slugs/snails (intermediate hosts) or by eating a paratenic host (e.g. small animals)
Adult worms live within the lungs, they produce larvae that are coughed up and swallowed.
46
What are the clinical signs of a cat infected with Aelurostrongylus abstrusus?
Some cats show respiratory signs e.g. coughing. May also have difficulties in breathing, neurological signs and/or lethargic.
47
What is the main lungworm (but technically a heartworm) in dogs?
Angiostrongylus vasorum
48
Describe the life cycle of Angiostrongylus vasorum
Larvae are passed in faeces
Infect intermediate host (snail)
Dogs ingest infected snail
Larvae migrate to the dog's pulmonary artery
Females lay eggs here which then enter lung circulation
Eggs hatch and 1st stage infective larvae migrate to alveoli
Larvae then coughed up and swallowed
49
What is the prepatent period of Angiostrongylus vasorum?
34 days
50
How can Angiostrongylus vasorum be detected?
Using a Angio Detect Test (Idexx)
51
Describe the anatomy of a cestode
Composed of a head (scolex), a segmented body made up of proglottids and a mature end.
The scolex may contain hooks or suckers to attach to intestine.
Each segment contains both male and female reproductive tracts so reproduction can occur between two segments of the same worm.
The segments mature and become more egg-filled as they move towards the tail end. They then drop off and exit via anus.
Eggs are released from the segment via a genital pore.
The embryo inside each egg cannot develop until the egg is ingested by an intermediate host.
52
Name (and spell!) 3 cestodes?
Dipylidium caninum
Taenia species
Echinococcus granulosus
53
Describe the life cycle of Dipylidium caninum
Mature segments are passed in the faeces.
Eggs are released via the genital pore into the environment.
Eggs are eaten by a larval flea.
Larval form develops in flea.
Flea ingested by a grooming cat/dog
Scolex attaches to the intestinal wall
Adult D. caninum in SI of adult cat/dog
54
What is the prepatent period of Dipylidium caninum?
3 weeks
55
What are the clinical signs of a cat or dog infected with Dipylidium caninum?
Little harm caused.
| Anal irritation.
56
How can Dipylidium caninum be treated/prevented?
Treatment with a suitable anthelmintic and a flea/louse control
57
What cestode infects just dogs?
Echinococcus granulosus
58
Describe the anatomy of Echinococcus granulosus
4 segments. The terminal gravid segment makes up about half of the length of the worm.
59
Describe the life cycle of Echinococcus granulosus
Segment passed in faeces each week.
Eggs released from segment in environment
Eggs are eaten by sheep
Sheep dies of natural causes eventually
Scavenging dog eats sheep's liver or is fed raw offal
The tapeworm is liberated in the intestine and matures to adult.
60
Name the 2 types of Ectoparasite
Insects and Arachnids
61
Describe the appearance of lice
Small. wingless, permanently parasitic insects. They are dorso-ventrally flattened. Possess claws for grasping hairs
62
What are the 2 main group of lice
Biting/ chewing
| Sucking
63
What is the latin name for the biting louse of cats?
Felicola subrostratus
64
What is the latin name for the biting louse of dogs?
Trichodectes canis
65
What is the Latin name for the sucking louse of dogs?
Linognathus setosus
66
Describe the life cycle of lice
Female lice lay their eggs on hairs of cat/dog
immature lice emerge from the eggs and progress through a series of moults to become adults
Entire life cycle takes about 4-6 weeks
67
Describe the appearance of fleas
Wingless, laterally-flattened, dark brown insects
| Have specialised legs for jumping and moving through coats. Mouthparts are adapted for piercing skin and sucking blood.
68
What the clinical signs associated with a flea infestation?
Skin irritation at the site of bite
can also have an allergic reaction to flea saliva (flea allergic dermatitis)
heavy infestation cause anaemia, transmission of Dipylidium caninum, FeLV and FIA
69
How can fleas be treated/prevented?
Environmental cleaning
Thorough vacuum
household flea spray
treat animals e.g. frontline
70
Describe the life cycle of the flea?
Female flea lays about 25 eggs per day after 2 days of feeding. Eggs drop into environment. Eggs hatch after about 2-24 days. Larvae emerge from eggs and undergo 2 moults. They pupate after about 7 days - the cocoons are stick and are camouflaged by environmental debris. The adults then emerge and seek host.
71
What is the Latin name for the cat flea?
Ctenocephalides felis
72
What is the Latin name for the dog flea?
Ctenocephalides canis
73
How can you tell the difference between the dog and cat flea under a microscope?
Ctenocephalides felis has many more combs around head
74
What can flies cause?
Myasis or 'fly-strike'. Invasion of host tissues by larvae of dipteran flies.
75
Describe the life cycle of Dipteran flies
Adult female green/bluebottle lay eggs in groups on their host animals in moist areas.
Eggs hatch after about 12 hours
Maggots feed on protein, grow and moult on the host animal -burying deeper into the skin.
Maggots then fall to the ground once fully developed and bury themselves when fully developed.
They then pupate and an adult fly emerges from 8 days after pupation begins
76
What are the 2 types of Arachnid Ectoparasites?
Mites and Ticks
77
What are the 2 types of mite?
Burrowing or surface
78
Generally describe the life cycle of mites
The entire life cycle of most parasitic mites occurs on the host with transfer from host to host - occurring through close contact.
79
What are the symptoms of a mite infection collectively known as..?
Mange
80
Name the 2 burrowing mites
Sarcoptes scabiei - dog mange mite
| Demodex canis - dog mange mite
81
What is the latin name for the cat mange mite?
Notoedres cati
82
Describe the infection/life cycle of Sarcoptes scabiei
Female mites burrow into the stratum corneum of skin and lay eggs within the burrowns. Immature mites hatch from the eggs, develop and the move on to create their own burrows
83
Where does a Sarcoptes scabiei infection usually start?
Hock, elbows or pinna
84
What are the clinical signs of sarcoptes scabiei ?
Thickened skin
Hair loss
Strong yeasty smell
extremely itchy and can cause self-trauma
85
How is Sarcoptes scabiei usually diagnosed?
Skin scrapes (usually under GA)
86
What should you be aware of when a patient presents with signs of sarcoptes scabiei?
Its Zoonotic
87
How is sarcoptes scabiei treated?
Medicated Amitraz baths regularly
Injections
Steroids and antibiotics to treat clinical signs
88
What is the name of the cigar shaped mite?
Demodex
89
What are the signs of Localised demodicosis?
Hair loss at site of infection
Normally face or forelimbs
Can clear on its own
Skin can become thickened
90
What are the signs of general demodicosis?
Lesions spread all over the body
| Likely the result of some sort of immune suppression
91
How is demodex transmitted?
Transmitted from mother to pup due to close contact
92
How many demodex mites need to be found to make a diagnosis?
1
93
How can Demodex be diagnosed?
Deep skin scrapes under GA
94
What is the treatment for Demodex?
```
Suitable acaricide
Not always cureable
Treat secondary infections with antibiotics
Clip animal
Invermectin injections and Amitraz baths
```
95
Name the non-burrowing mites
1. Otodectes cynotis (ear mite)
2. Cheyletiella (walking dandruff)
3. Neomtrombicula autumnalis (harvest mite)
96
What species are affected by ear mites?
Dogs cats and ferrets
97
What do Otodectes cynotis look like?
Unjointed stalks - long legs with suckers on end
| Off-white colour
98
How long does the entire life cycle of Otodectes last?
3 weeks
99
How is Otodectes transmitted
Female mite lays eggs on the host. The mites transfer from animal to animal by close contact.
100
What are the clinical signs of Otodectes?
Most can harbour mites and show no signs of irritation
Early infection shows a brownish waxy discharge in the ear canal which becomes itchy
Scratching or shaking head
101
How is an otodectes infection diagnosed?
Through visual examination with an auroscope
102
What is the treatment for an Otodectes cynotis?
Clean the ear
Prescription medication e.g. canural
antibiotics and anti-inflammatories should be used to treat irritation and infection
103
What is the latin name for walking dandruff?
Cheyletiella
104
What species are cheyletiella found in?
Dogs Cats Rabbits
105
What are the clinical signs of Cheyletiella?
Live on the hair and go into the skin to feed
| The mite causes a dermatitis which causes skin scales to shed in the hair
106
How is Cheyletiella diagnosed?
Extremely contagious and transfers through close contact
107
How can cheyletiella be diagnosed?
Coat brushing
Tape strips
Superficial skin scrapes
108
How can Cheyletiella be treated?
Invermectin injections
Amitraz baths
Special shampoos
Environment needs to be thoroughly cleaned and vacuumed
109
How long is the life cycle of Cheyletiella?
2 weeks
110
What is the latin name for the harvest mite?
Neotrombicula autumnalis
111
What is the host of Neotrombicula autumnalis?
Dog
112
What does Neotrombicula autumnalis look like?
6 legs
Bright Orange and Haory
Seen as orange clusters
113
Where are neotrombicula autumnalis found?
Found in between pads, legs and face
114
Briefly describe the life cycle of Neotrombicula autumnalis
Parasitize an animal for a short time in high summer - autumn. Once they have fed, they drop off into the environment and complete their life cycle. They then attach to a passing dog
115
Name the two species of tick?
Ixodes Ricinus - sheep tick
| Ixodes canisuga - dog tick
116
Describe the life cycle of a tick?
3 host cycle
Adult tick feeds on blood of the host (e.g. sheep - host 3)
Adult female tick falls to the ground when fully engorged with blood. Female lays several 1000 eggs on the ground. The larval ticks hatch and about a year later attach to host and feeds for about 6 days (e.g. rat - host 1).
Larval ticks fall off once fully fed and moults to nymph stage. The nymphal stage jumps onto the next host the following year (e.g. dog - host 2).
Nymphal tick falls off once fully fed. Adult tick then jumps onto host again (Host 3)
117
What are the clinical sings of a tick infestation?
Visual Spot
Can show symptoms of Lyme's Disease or Babesiosis
Fever, lameness, joint swelling, local inflammation
118
What is the treatment for Ixodes?
Safe removal of tick with tick remover
Skin disinfection once removed
Treat Lyme's Disease/ Babesiosis
Use a suitable acaricide
