Pig Nematodes Flashcards
What nematode parasites of pigs affect indoor and outdoor pigs?
What nematode parasites only affect outdoor pigs?
Indoor and outdoor
- Ascaris suum
- Strongyles ransomi
- Trichuris suis
- Oesophagostomum spp
Outdoor
- Hyostrongylus rubidus
- Metastrongylus apri
What parasite is this?
Describe its characteristics
When is it infective, what type of life cycle does it have?
Ascarid worms- large, white, fleshy worms
Direct life cycle- may include paratenic host
Infective stage- egg containing L2/L3 bottom right
Eggs highly resistant and long lived
Infections usually stimulate strong immunity
Where in the world is Ascaris summ common in pigs- what type of farming
How big are female and male worms
How big are eggs?
World-wide distribtion- common, intesively and extensively housed pigs
Male up to 25cm
Females up to 40cm
Females produce lots of eggs- thick walled
70um diameter
Describe the ascaris suum lifecylcle
Typical ascarid life cyle
Eggs passed in faeces
Develop on ground- temp dependent ~4 weeks
Egg containing infective larvae (L2/3) ingested- pig or earthworm (paratenic)
Hepato-tracheal/pulmonary migration- larvae migrate via liver to lungs, coughed up and swallowed, larvae develop in small intestine through L4-L5
PPP ~8 weeks
Describe the pathogenesis of Ascaris suum
Hypersensitivity response to migrating larvae-
Liver- fibrous reaction ‘milk spot’
Lungs- transient pneumonia
Adults in small intestine-
Poor weight gain
mechanical blockage in small intestine
Major economic costs
reduced weight gain
liver condemnation
How are ascaris suum- diagnosed, treated and controlled?
Diagnosis
Abbatoir reports- identification of ‘milk spots’
Transitent respiratory disease
Reduced weight gain
Patent infections- eggs in faeces
Treatment and control
Anthelmintics
Non-anthelmintic control- steam cleaning indoor pens, control more difficult in outdoor units
What species of strongyle is only in pigs
What age of animal is affected
Describe adult worms and eggs
Strongyloides ransomi
Typically very young animals- good immunity after exposure
Adult worms- small ~6mm, hair like, not ovijectors
Eggs- thing shelled, embryonated
Describe the lifecyle of strongyloides
Parasitic asexual or free living life cycle in pig
- Eggs (embryonated) are passed in faeces, moult to L3
- Some eggs- free living- L3 continue development to L4/5 and adults, feed on bacteria in soil, allows build up
- Parasitic- L3 ingested and penetrate mucosa of oral cavity and migrate to SI via lungs
- Can migrate to udder of burrow and develop
- Larve burrow into mucosa and develop- only females develop- parthenogenesis
- Transmammary infection from L3 ingested within the milk
- Larvae in udder can become arrestes until farrowing
How do strongyloides cause disease?
How is it diagnosed, treated and controlled?
Disease
Infection induces strong immunity- older pigs usually do not have clinical signs
Piglets- transmammary infection- heavy- diarrhoea, anaemia, emacation
Diagnosis-
patent infections- eggs in faeces
abbatoir reports- adults in intestinal mucosa scrapings
immature worms- minced tissues, Baermann technique
Treatment- Anthelmintics- MLs, BZs
Control- keep environment clean
What species are commonly infected by trichuris spp in UK?
Where is trichuris suis found in pigs?
Describe its lifecycle
What are the clinical signs?
Common in UK- ruminants, dogs, pigs
Trichuris suis- large intestine of pigs
Characteristic eggs- highly resistant, remain viable for upto 11 years
Direct lifecycle- egg development >16 degrees, 10-12 weeks,
Infective stage- egg containing L1
PPP 6-8 weeks
Short period of egg laying period
Clinical signs- weight loss in pigs, colitis in growing pigs
What parasite is this found in a pigs small intestine?
Whip worm
Trichuris spp- Trichuris suis
Where are oesophagostomum spp found in pigs?
What other species are infected
What size are adult worms, what feature is diagnostic?
Describe their lifecycle
Describe its pathogenesis?
How is an infection diagnosed and controlled?
Large intestine- sheep and cattle
Adult- ~2m, cephalic vesicle
Typical strongyle- direct
L3 infective, L3-L4 in mucosa- nodules
PPP 3-6 weeks
Pathology- nodules- intestinal wall thickened and necrotic, little damage in mucosa of large intestine by adult worms
Diagnosis- nodules and adult worms PM, faecal examination
Treatment/control- BZs, MLs, good sanitation
Where is the hyostrongylus rubidus found in outdoor pigs?
What kind of life cycle does it have?
What is its PPP?
What are the signs of heavy infections?
How is it diagnosed and treated?
Red stomach worm- 6mm
Direct life cycle- PPP- 3 weeks, Hypobiosis
Parasitic gastritis- Heavy infections: inappetance, anaemia, weight loss, ‘thin sow syndrome’
Diagnosis- faecal examination- larval culture, PM examination
Treatment- BZs, MLs (doramectin and ivermectin)- effective against hypobiotic larvae as well
Describe the life cylce of metastrongylus apri
- Earthworm ingested by pig
- L3 released in gut, L3-L4 in mesenteric lymph node
- L4 reaches lung via lymphatics and blood stream
- Matures to adult in the lungs- lumen of the bronchi and bronchioles
- Larvated eggs shed in faeces
- Hatch, L1 infects earthworm
- L1-L2-L3 in earth worm
PPP 3-4 weeks
What parasite is this?
What stage of the parasite is this?
Adults found in bronchi/bronchioles
Metastrongylus apri
Picture shows L1- tail ends in a knob
Thick larvated eggs
