The presentation covers various aspects of deworming in animals. It includes the symptoms of worm infestation, harms caused by parasites, various groups of anthelmintic drugs and their mode of action and some natural anthelmintic products.

1. An Overview of Anthelmintics
Dr Nisar Ahmad, PhD
Assistant Professor
Department of Parasitology
UVAS, Lahore

2. What is Deworming?
Sometimes known
as Worming or Drenching, is the giving of
an Anthelmintic drug (a wormer, dewormer,
or drench) to an animal

3. How Parasites Hurt Animals
•Absorb digested nutrients
•Suck blood
•Cause mechanical obstruction
•Destroy tissue
•Secret toxins
•Immune Suppression

4. Symptoms of Worm Infestation
•Animal lacks vigor: Dull and depressed
•Poor appetite
•Loss of body weight
•Diarrhea with mucus, blood or worms
•Animal eats soil or other organic matters
•Rough hair coat and anemia

5. Symptoms of Worm
Infestation
Diarrhea

6. Parasitic Infestation
Emaciation

7. Parasitic Infestation
Anemia
Submandibular Swelling

8. Risk Factors For Parasites
•Warm Weather
•2 inches of rain in a month
•Pasture Grazing
•High Stocking Rate
•Thin Animals
•Animal in Lactation
•Long Residence on a Pasture

9. Classification
Four families of drugs for internal parasites
1. Benzimidazoles (white dewormers) –
Albendazole, Fenbendazole, mebendazole, and
Oxfendazole
2. Imidazothiazoles –Pyrantel, Levamisole, and
Moratel
3. Macrolytic Lactones or Avermectins Ivermectin (Ivomec), Doramectin, and
Moxidectin
4. Others- Praziquantel, Clorsulon, etc

10. Spectrum of Anthelmintics

12. Guideline for Anthelmintic
Dosages
• Albendazole -20 mg/kg (Not in 1st trimester)
• Fenbendazole- 10 mg/kg
• Ivermectin- 0.4 mg/kg
• Levamisole- 12 mg/kg
• Moxidectin- 0.5 mg/kg

13. Mode of action of Avermectin
• Ivermectin binds with high affinity to
glutamate-gated chloride channels which
occur in invertebrate nerve and muscle cells,
causing an increase in the permeability of the
cell membrane to chloride ions with hyper
polarization of the nerve or muscle cell. Hyper
polarization results in paralysis and death of
the parasite either directly or by causing the
worms to starve.

14. Avermectin

15. Mode of action of
Benzimidazoles
• Benzimidazoles selectively bind to
nematode ß-tubulin, thus preventing the
formation of microtubules and so
stopping cell division. Impaired uptake
of glucose, leading to depletion of
glycogen which causes the nematodes to
starve to death.

16. Mode of Action of Praziquantel
• Praziquantel works by causing severe
spasms and paralysis of the worms'
muscles. This paralysis is accompanied
by a rapid Ca 2+ influx inside the
parasite. This influx of Ca results
in tetanic contractions of the parasitic
musculature and an intense vacuolation
of their integument.

17. Selection of a Dewormer
• Animal being treated (calf vs. cow, beef vs. dairy)
• Product efficacy
• Ease of application
• Broad Spectrum of control ( immature, mature,
inhibited)
• Cost effectiveness
• Slaughter/milk withdrawal time
• Personal Safety

18. Deworming in sheep/goat
• Sheep and goats are susceptible to worms due to
their close grazing behavior and slow-to-develop
immunity. Goats are more susceptible than sheep
when forced to graze (versus browse)
• Lambs should be wormed at approximately 8 weeks of
age, and again every 4-8 weeks until a year of age.

19. Cont…
• Ewes should be wormed 2-4 weeks
before lambing to reduce the passage of
parasites to the lambs.
• Does in early pregnancy (up to 2
months) should not be dewormed to
avoid abortion.
• At least once per year, goats/sheep
should be dewormed for tapeworms

20. Cattle and Buffalo
• Cattle can be infected by roundworms
(nematodes), tapeworms (cestodes) and flukes
(trematode)
• Roundworms are considered the most
economically devastating internal parasites of
livestock
1. The barber pole worm (Haemonchus)
2. The small brown stomach worm
(Ostertagia)
3. Cooperia

21. • Internal parasites of lesser concern are
tapeworms and lungworms
• Tapeworms, which are visible in the manure,
can cause weight loss and death in extreme
cases.
• Tapeworms can be controlled by administering
an Anthelmintics from the benzimidazole
family

22. Commonly available Anthelmintics
Oxyclozanide, Oxfendazole
Cobalt and Selenium
Albandazole

23. Nitroxynil
Ivermectin

24. Cont…
TRADE NAME
GENERIC NAME
Profax
(Oxfendazole)
Fasisym
(Triclabendazole)
Zanil
( Oxyclozanide)
Nilzan plus
(Levamisole + Oxyclozanide
+Selenium+ cobalt)

25. Characteristics of a Good
Dewormer
• Not Poisonous
• Easy to administer
• Effective for all stages of parasites
• Economical
• Effective for a longer period of time
• Act specifically at the target site

26. Natural/Herbal Dewormer

27. Efficacy of a Dewormer
• An effective dewormer will reduce
fecal counts by 95% 7-14 days after
administration.
• Fecal Egg Count before deworming,
1,000 eggs per gram(EPG)
• For example:10 days after deworming
200 EPG= 80% Fecal Egg Count
Reduction.

28. Anthelmintics Resistance
• Drug resistance in parasites is extremely common.
The effectiveness of an Anthelmintics should always
be tested before being used.
• Do not worm unnecessarily
• Make sure you are giving the correct dose. Don’t
overdose or under dose
• Change the type of wormer used so you are using a
different type of drug to prevent resistance

29. ANY
QUESTIONS ?

30. THANKS