Part of 2020 Weekly Worm Webinar Series. Presentation by Dr. Kwame Matthews from Delaware State University.

1. Kwame Matthews
Small Ruminant Specialist
Delaware State University
Kmatthews@desu.edu
302-857-6540

2.  An organism lives in or on another organism (its host)
and benefits by deriving nutrients at the host's expense
(Oxford Dictionary)
 Internal Parasite
 Organisms that live inside animals
 Examples: Barber Pole Worm, Tapeworms, Coccidia, Etc.
 External Parasite
 Organisms that live outside an animal
 Examples: ticks, lice, flies, fleas, mites, etc.
 Control: Permethrin and Ivermectin

3.  Sheep, goats and camelids can be
affected by many internal and
external parasites
 Two types:
1. Helminths
 Nematodes (roundworms)
 Cestodes (tapeworms)
 Trematodes (flukes)
2. Protozoa (coccidia)
 Most important parasites are
gastrointestinal nematode (GIN)
 High worm burden result in a reduction
in production and increase in clinical
signs

4.  Strongylid nematode that causes
severe set back to the economic
production of small ruminants
 Blood-sucking parasite
 Prolific egg layers with short life cycle
 Symptoms
 Pale mucus membranes (anemia)
 Bottle jaw
 Sudden death
 Weight loss, low body condition and
anorexia
Pale membranes

5.  Adult worms are between 20 mm
or ¾ inch (male) and 30 mm or 1
inch (female) long
 Female parasites are prolific egg
layers, producing 5,000 – 10,000
eggs per day
 Eggs are passed in manure
 Eggs hatch and larvae develop in
the manure (environmental
protection).
 Third-stage (L3) exit manure and
moves on to forage where they
are ingested
 Larvae develop to adult inside the
host

6.  Development of worm larvae occurs
between 50 – 96 °F.
 Minimum time eggs take to develop to
infective L3 is 3 – 4 days
 Ex-sheath their cuticles in the rumen
and move to the gastric pits of the
abomasum
 L4 then develop to a fully mature
adult
 Lancet, in their oral cavity, is used to
cut blood vessels in the host
abomasum for blood consumption
 0.05 ml of blood per worm per day

7.  Develops most successfully in
warm, wet climates
 Hot, humid summers with long
grazing seasons favors
development
 Southeast is ideal
 Northeast (May – September)
 West (less of a problem unless
irrigation is practiced)
 Does not survive well in freezing
temperature
 Can still be successfully established
in cold states and countries.

8.  Individual adult worms survive for
only a few months
 L3 Larva Survival on pasture:
 Once metabolic reserves are used up
they die since cuticle prevent feeding
 Survive longer in cool, moist conditions
 Die quicker in hot weather
 In temperate areas, pasture considered
safe after 6 months
 In hot summer, pasture considered safe
after 2 – 3 months
 Die even quicker if pasture is used for
hay or plowed prior to re-use

9.  Larval migration on forage is
affected by temperature, soil
moisture, and humidity.
 Larvae can migrate vertically (4
– 6 inches) in moisture on grass
blades
 Pasture management essential
to parasite control
 Allow animals to browse on
bushes and taller plants
 Do not survive well on other
surfaces than grass area

10.  Can go into a period of
“hypobiotic” (arrested)
development during winter to
survive
 Does not continue development and is
metabolically inactive
 Delay adulthood and egg production
 Occurs after infection and before
development is complete
 Occurs when conditions are least
favorable for larvae and egg
development
 Will survive the winter in the
arrested stage

11.  In warmer climates,
hypobiosis less important in
parasite transmission
 Development resumes in late
winter and spring
 Coincides with kidding and
lambing seasons as animals
immune system get weaker
 Young susceptible animals as
they begin to graze
 Contamination of pasture in the
spring (kidding/lambing time)

12. Worm
Numbers
Blood
Loss/Day
50 2.5 ml
100 5 ml
200 10 ml
400 20 ml
800 40 ml
1600 80 ml

13.  The most common method used to
control GIN infection in the US is
anthelmintic (dewormer) drug treatment
 Overuse and misuse of the available
dewormers, this has led to the prevalence
of anthelmintic resistance in small
ruminant GIN
 Drug resistance is well documented for
all classes of anthelmintics
 Even the new drugs have parasite
resistance

14. Sustainable Integrative
Parasite Management
 Effective management
 Target selective treatment
 FAMACHA© system
 The Five Point Check©

15. http: //www. wormx. info
The American Consortium for Small Ruminant Parasite Control
was formed in response to the critical state of the small
ruminant industry associated with the emergence of
anthelmintic resistant worms. The SCSRPC is a group of
scientists, veterinarians, and extension specialists devoted to (1)
developing novel methods for sustainable control of gastro-
intestinal nematodes in small ruminants and (2) educating the
stakeholders in the small ruminant industry on the most up-to-
date methods and recommendations for control of
gastrointestinal nematodes.