09 endoparasite prceduresx - Moodle @ UCOL

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COLLECTIONS OF SAMPLES

PPE required and nil per
os

in the area

All samples potential zoonosis

Faecal samples


Min sample size: 2g egg count, 3.4g drench test, 7g larval culture


Witnessed elimination small animal submission


Individual rectal or pooled samples of in contact animals for large animal
submission

Autopsy


Decant and sediment or sieve sections of GIT contents for parasites


Scrape GIT lining and examine separately

Blood sample


Collect in
EDTA


STORAGE AND CLEANING

Preserve parasite samples in formalin or 70% alcohol and label before storage

Faecal samples must be sent in clean water tight containers
NOT inside out rectal
gloves as in notes
and labelled

Blood samples are stored in the fridge


Contents of fresh and formalised samples must not mix,

Formalised samples must
NOT
be stored in the fridge



DIAGNOSTIC PROCEDURES

Gross exam

Microscopic exam


may require accurate measurement for differential
Dx
,


usually the 4x and 10x objective lenses are sufficient for visualisation


40x must NOT be used for faecal egg counts (risks breaking the lens or counting chamber)


Direct smears quick but not accurate
Dx

of low burdens,


Direct smears for
protozoal

oocysts

or
trophozoites

may require stains


Blood smears (microfilaria concentrate in the feathered edge seen in differential, or in the buffy coat after
spinning for PCV, other blood parasites may be detected in RBC)

Floatation and sedimentation techniques concentrate evidence of parasite burdens


Flotation solutions use SG = 1.2
-
1.25
eg

saturated salt solution(most parasite eggs detected this way)


Sedimentation techniques usually use water to help separate parasite material from debris by centrifuging the
sample(
trematode

eggs too heavy for flotation)

Larval culture is used for research and identification of species of nematodes

The
Baermann

technique is used to separate and concentrate larvae from material from larval culture and from
faeces submitted for diagnosis
Dx

of
lungworm

ENDO
PARASITICIDES

Organophosphates


Occasionally still used in horse drench (therapeutic range very narrow)

3 Traditional drench families for production animals round worm infestations


Benzimidazoles

(white drenches)


Membrane depolarisers


Macrolides

Trematode

treatment


The drug of choice is
Triclabendazole
(a
benzimidazole
),
bithianol

is also used


Closantel

is another common active ingredient which may be added in combination drenches

Cestode

treatment


Praziquantel

is often added to formulations if the spectrum of the other active ingredient does
not include tapeworms

Drug for small animal
endoparasite

infestations


Selamectin

(a
macrocyclic

lactone) broad spectrum
endoand

ectoparasiticide
, is not routinely
used in large animal formulations


Piperizine
: narrow spectrum action against round worms like
ascarids
-
safe in young animals


PHARMACODYNAMICS AND FORMULATIONS

Formulations are many and varied to suit the species and husbandry issues.


Most large animal formulations are formulated as pour
-
ons

or oral drenches,


Most small animal formulations are tablets
.

Efficiency is affected by:


Routes of administration,


absorption


activation of the oesophageal groove reflex,
(present in 40% of older sheep)


particle size


binding to plasma protein


resistance of the life cycle stages


Timing to match the seasonal incidence of disease

Explain how these factors affect efficiency to a buddy




RESISTANCE

Rapid build up of resistance is related to


Frequent treatment


Underdosing

and other improper administration issues


The presence of side resistance from related drugs


Long term use of the same active ingredient

Drench testing may identify suspected drench resistance


Random sample of 10 animals faecal samples straight after drenching and 2
weeks later (supervision of drench techniques by veterinary professionals doing
diagnosis)

Describe how to reduce the build up of drug resistance in wormers


DRUGS FORMULATIONS AND DOSING
SCHEDULES FOR PUPPIES, AND OLDER DOGS

Syrups or pastes are required for very young puppies, tablets are less messy later

Transplacental

infection with
Toxocara

results in patent infection and environmental contamination from 23 days
postpartum (
piperizine

and
pyrantel

both safe)

If hookworms are present in the environment pups should be dosed 10
-
14 days post partum (
piperizine

not effective,
pyrantel

is)

Flea tapeworms are seldom pathogenic(the fleas are more important)
praziquantel

is effective

Dosing schedules for older animals that are ‘recommended’ are controversial. Be aware of the best practice
recommendations in the code of welfare for dogs. This recommendation covers the wider spectrum of conditions dogs
are kept in in NZ but may be unnecessarily frequent for town dogs that are kept in hygienic circumstances and may
contribute to drench resistance arising. Faecal testing of older animals to ensure dosing is necessary, may help avoid
this or help identify the problem so the drug chosen targets the parasites present effectively

Animal Welfare (Dogs) Code of Welfare
2010
pg

25

http
://
www.biosecurity.govt.nz/files/regs/animal
-
welfare/req/codes/dogs/dogs
-
code
-
of
-
welfare.pdf


Puppies should be wormed with an effective roundworm treatment at two
-
week intervals
from two
to 12 weeks of age.
Thereafter they should be wormed every three months, using a
broad spectrum
wormer, or as recommended by a
veterinarian
.


If dogs are tethered or in runs on bare earth, they should regularly be moved to fresh
ground and
the area kept clear of
faeces
, to prevent the build
-
up of hookworms

DOSING CATS FOR WORMS

The problems cats and kittens have with worms are very similar to puppies and dogs

They host zoonotic worms also yet owners are usually less aware and less energetic
about dosing felines routinely for worms

There is no
transplacental

infection of kittens so initiation of routine worm dosing is
recommended to start a week later in kittens

Animal Welfare (Companion
Cats) Code
of Welfare 2007

http://
www.biosecurity.govt.nz/files/regs/animal
-
welfare/req/codes/companion
-
cats/companion
-
cats.pdf

Kittens should be wormed every 2 weeks, starting at 3


4 weeks of age and
continuing to 3 months of age. Cats over 3 months of age should be wormed
every 3 months

FARM ANIMAL
ENDOPARASITE

CONTROL
PROCEDURES AND DIAGNOSIS

Management techniques to reduce worm problems


Dung removal


harrowing pastures


Rotational grazing with other species or classes of stock(beware of mixing goats
and sheep)


Impervious yard materials(
strongyloides
)

Development of resistance on Commercial farms and lifestyle blocks will be related to
management techniques used and efficacy of drenching protocols