P
Whipworm (dog only)
Tapeworm
Roundworm
Hookworm
Lungworm (cat only)
The importance of pre-patent periods
PRE-PATENT PERIOD
Most anthelmintics do not have residual activity – they kill worms present at the time of administration but provide no forward protection. Deworming protocols should therefore be designed to kill newly acquired parasites before they can shed infective forms (eggs or larvae).
The time period between infestation with a parasite and when infective forms
(eggs or larvae) are detectable.
THE DOSING INTERVAL SHOULD BE LESS THAN THE PRE-PATENT PERIOD FOR WORMS OF ZOONOTIC CONCERN.
The significance of pre-patent periods and deworming intervals e.g. roundworm ( Toxocara canis ) Pre-patent period – approximately 5 weeks
Monthly deworming eliminates newly acquired roundworms before they begin shedding eggs, reducing environmental contamination and minimising zoonotic risk.
0
3 months
2 months
1 month
Deworming Every Month
Pre-patent period
Pre-patent period
So
Pre-patent period
Worms killed before they begin shedding
Worms killed before they begin shedding
Worms killed before they begin shedding
0
1 month
2 months
3 months
Deworming Every 3 Months
Pre-patent period
Faecal shedding of eggs
Up to 200, 000 eggs per female worm per day for 42 days (before next dose given) = 8.4 million eggs in the enviroment from a single worm!
Boehringer Ingelheim Animal Health New Zealand Ltd Product Guide 2022 31
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