SA Hookworms and Filarial Nematodes Flashcards Preview

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Flashcards in SA Hookworms and Filarial Nematodes Deck (29):
1

Name two species of hookworm in dogs.

Uncernaria stenocephala, Ancylostoma caninum

2

Name two species of human hookworm.

A. duodenale, A. americana

3

Bunostomum is a hookworm of which species?

Sheep and cattle in the tropics

4

Describe the morphology of Uncinaria stenocephala.

  • 1 cm long
  • Hooked appearance 
  • Large buccal cavity
  • Two cutting plates

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5

Foxes are an example of what type of host of Uncinaria stenocephala?

Where in the canine body would U. stenocephala?

Reservoir host

Small intestine where they feed on blood and mucosa

6

Outline the methods of infection of U. stenocephala.

  1. Ingestion of L3
  2. Percutaneous infection

7

What is the PPP of U. stenocephala?

15 days

8

True or False.

U. Stenocephala are capable of migrating.

True, they migrate to distant tissue such as fat or skeletal muscle.

9

What clinical signs are associated with Uncinaria Stenocephala?

  • Not highly pathogenic
  • Anaemia
  • Wt loss
  • Diarrhoea
  • Pedal dermatitis with repeat percutaneous infection

10

How can Uncinaria stenocephala infection be treated and controlled?

  • Anthelmintics - BZ, PYR, MOX
  • Dry conditions
  • Concrete rather than earth runs

11

Which countries can Ancytostoma caninum be found in?

Tropics

Subtropics

USA

Ocassionally UK

12

Outline the migratory routes of Ancylostoma caninum when dogs are infected:

  1. Percutaneously
  2. Ingested

  1. Percutaneously - L3 reach the blood stream and travel to the lungs where they are coughed up and swallowed
  2. Ingestion - penetrate the buccal mucosa and migrate to the lungs
    1. Migrate to the mammary glands when bitch is lactating (TMT)

13

How much blood is Ancylostoma caninum capable of consuming per day?

0.1mls blood per day per worm

14

Outline the clinical signs associated with Anocylostoma caninum.

  • Severe acute anaemia which may occur in the prepatent period
  • Chronic anaemia that results in depletion of iron reserves, especially in older puppies.
  • Poor growth and body condition.
  • Dermatitis
  • Lethargic
  • May have bloody/ mucous diarrhoea

15

Outline the key features of the order Spirurida.

  • Generally large (2-50cm)
  • Eggs larvate in utero or L1 are born live
  • Invertebrates are intermediate hosts
  • Adults parasitize GI tract and other tissues

16

Name the main filarial nematode species.

  • Dirofilaria
  • Onchocerca
  • Brugia
  • Wuchereria Bancrofti

17

Heartworm

Dirofilaria immitis

18

In which areas of the world is D. immitis considered endemic?

  • Iberian Peninsula
  • France
  • Italy
  • Eastern Europe
  • (3 cases have been reported in the UK)

19

Name the vector which transmits Dirofilaria immitis.

  • Mosquito
    • Culicine
    • Anophenline

20

Outline the lifecycle of Dirofilaria immitis.

  1. Adult worms in pulmonary arteries or right ventricle of the heart
  2. Microfilariae (L1) in the blood after 6-9 months
  3. Dog is bitten by mosquito which ingests L1
  4. L1 moult to L3 
  5. Infective L3 innoculate the dog when it is bitten by the mosquito
  6. 3-4 days: Moults to L4 migrates to abdomen
  7. 2 months: Moults to L5 penetrates jugular

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21

How big would juvenile Dirofilaria immitis be compared to adult females and males?

  1. Juvenile - 2-4cm
  2. Adults
    1. Female - 30cm
    2. Male - 20cm

22

Where in the body are adults Dirofilaria immitis found?

Pulmonary arteries

Right ventricles in heavy infections

23

Which other species have Dirofilaria immitis been found in?

What clinical signs/ changes to the lifecycle are identified in these species?

  1. Humans
    1. Usually asymptomatic
    2. Pneumonitis - coin lesions on chest radiogram (granuloma around dead/dying worm)
    3. Usually never microfilaraemic
  2. Cats and ferrets
    1. Low worm burdens (1-3 adults)
    2. Adult worms are stunted
    3. Amicrofilaraemic/ transient microfilaraemia

24

Describe the clinical signs associated with Dirofilaria immitis in dogs and cats.

Dog

  1. Chronic exercise intolerence
  2. Chronic cough, dyspnoea, lipothymia
  3. Right sided CHF - ascities, anorexia, death (respiratory distress and cachexia)
  4. Acute caval syndrome - IV haemolysis and haemoglobinuria

Cat

  1. GI/ neuro signs alongside pulmonary signs
  2. Sudden death more common than in dogs

25

Describe the modified Knott test. What is it used for?

Haemolysis, centrifugation and staining with methylene blue before direct examination and identification of microfilariae

Used for diagnosis of Dirofilaria immitis

26

How is Dirofilaria immitis dignosed?

  • Knott test
  • Immunoassays for adult worm ag/ab
  • Radiography 
  • Echocardiography

27

Where would you find adult Dirofilaria repens?

Subcutaneous nodular swellings

28

How can D. immitis and D.repens be differentiated?

Repens - larger 

Morphology

Staining with acid phosphatase

29

How can Dirofilaria infection be prevented and treated?

  1. Prophylaxis - MLs monthly prevents larval development but x adulticidal
    1. Usually given year round
    2. IVM given at low doses (selamectin/ milbemycin also)
  2. Treatment
    1. Melarsomine (only approved)
    2. Restricted exercise for 30-40days
    3. ​Doxycycline (long dose) and IVM - macrofilaricidal treatment
    4. Risk of thromboembolism