Nematodes: Strongylida Flashcards
What phylum to nematodes belong too?
phylum Nemathelminthes
What are the general characteristics of nematodes?
Free living or parasitic
Usually unsegmented, elongated, and cylindrical in shape
Complete alimentary canal
Sexes usually separate; the female are generally larger than the males
The nematode male reproductive system consists of?
Two testes opening into a seminal vesicle and vas deferens which open into cloaca
Many males have copulatory bursa
The nematode female reproductive system consists of?
Two ovaries, an oviduct, and a uterus
What is the life cycle of the majority of nematodes?
Egg > L1 > L2 > L3 > L4 > L5/immature adult > Adult
(Molting of the cuticle separates the L1-L5)
Some parasites have microfilaria instead of the traditional L1
What are the key points to parasite identification?
SSH (size, site, host)
Clinical signs
Morphological characteristics
In the the live animal what are the common identification stages of a parasite?
Eggs -feces
L1/L3
Adults (sometimes in vomit or feces)
What morphological characteristics can be used to identify a parasite?
Shape (curled, hooked, whip) Mouth (shape/teeth) Esophagus Bursate male (or lack of) Vulva
What are the common features of parasites in the order strongylida?
Direct life cycle, infection by L3
Eggs: thin shelled; oval; average size
Arrested development of larvae
Males have bursa
Ancylostomatoidea are in what order?
Strongyloidea
What are the features of Ancylostomatoidea
Small: 1-2cm Egg: thin shelled, oval, average size Adults in small intestine Buccal capsule with teeth/cutting plates (anemia) Limited immunity
Host of Ancylostoma caninum
Dog and fox
Paratenic hosts
What are the 5 modes of infection of ancylostoma caninum
Percutaneous or penetration of oral mucosa Per os Paratenic host Transplacental (rare) Transmammary (important)
What are the sites of infection of Ancylostoma caninum?
Small intestine
What is the pathogenesis of Ancylostoma caninum?
Acute or chronic hemorrhagic anemia
Pups infected by transmammary route
Moist eczema with percutaneous infection
What are the clinical signs of Ancylostoma caninum?
Acute -anemia, lassitude, respiratory disease (lung migration), pneumonia, diarrhea
Chronic infections -weight loss, poor hair coat
What is the treatment and prevention for Ancylostoma caninum
Anthelmintics for adults/ larvae (some species specific, treat)
Larval leakage
Young pups: iron, blood transfusion
Nutrition
Treat pups and adults
Treat pregnant bitches at least once during pregnancy
2, 4, 6, and 8 weeks of age
Ancylostoma tubaeforme hosts
Cats
What is the transmission of Ancylostoma tubaeforme?
Per os
Percutaneous
Paratenic hosts
NO TRANSMAMMARY
What are the hosts of Ancylostoma braziliense?
Dogs and cats
Ancylostoma braziliense transmission?
Per os
Percutaneous
Paratenic hosts
What is the significance of Ancylostoma braziliense?
Most zoonotic
Cause cutaneous larva migrans
What are the hosts of uncinaria stenocephala?
Dogs, cat, and foxes
Paratenic
What is the uncinaria stenocephala transmission?
Per os
Percutaneous uncommon
Where are A. caninum and A. Tubaeforme found?
Throughout the US (more southern)
Where are Uncinaria sp found?
Northern US/ Canada/ Ireland (cooler climates )
Parasites in the superfamily strongyloidea have what different characteristics from other strongylida?
Well developed buccal capsule
Thick body
In the family strongylidae, what are the common names of two subfamilies
Large strongyles
Small strongyyles / cyatostomins
Small strongyles are also known as?
Cyathostomins
What is the different in PPP between large strongyles and cyathostomins?
Large: 6-11months
Small: 1.5-4months
Where are the adult large stronglyes and cyathostomins located?
Lumen of large intestine
How are cyathostomins identified?
Adults are <1.5cm
Mouth capsule rectangular or square
Egg typical strongyle
What is the PPP of cyathostomins?
6wks to 2-3months
Arrested development up to 2 1/2 yrs
What are the sites of infection of cyathostomins?
Larvae through large intestine mucosa
Adults in lumen of large intestine
What is the pathogeneis of cyathostomins?
Larval cyathostominosis
Lymphocytic and eosinophilic infiltration
Catarrhal colitis
Protein losing enteropathy
What are the clinical signs of cyathostomin parasites?
Chronic diarrhea, colic
Seasonality
Severe weight loss, edema
(Associated with emergence of L4)
How are cyathostomins infections diagnosed?
Eggs in fecal examination (McMaster)
Distinguish L3s from large stronglye L3
Eggs in feces of foals <6wks is due to coprophagia (too young for PP)
How do cyathostomins differ based on climate
Northern - larvae arrest during winter and emerge as adult in spring (egg count increase in spring)
Southern - larvae encysts during summer, transmission during winter
What circumstances can lead to larve burdens/accusations of larvae?
Inadequate treatment during the preceding grazing season
Overstocked pastures
Mare is source of infection for foals/ reinfection of itself
How do you treat cyathostomins infections?
Mucosal larvae stances
FBZ for 5days or MOX single dose
-> often resistant to drugs
How can you prevent/ manage cyathostomins?
Accurate diagnosis
Pasture management
- treat “high shedder”
- clean up feces
- mixed grazing
- do not overstock
What is anthelmintic resistance
Worms that survive drug treatment, exist prior to first used of a drug
- drug exposure selection
- > increase level of drug resistance genes in a population
How can you decrease anthelmitic resistance?
Selective treatments
Decrease use = decrease exposure = decrease resistance
Only treat problem causing or suffering animals
Protects refugia
What is refugia?
Parasites that are not exposed to anthelmitics
Susceptible worms in environment
What family of parasites contains the Oesophagostomum spp?
Chabertiidae
What is the scientific name for the nodular or pimply worm?
Oesophagostomum spp
What are the hosts of Oesophagostomum spp?
Cattle, sheep, goat, swine (host specific)
What is the distribution of Oesophagostomum spp?
Warmer climates
Adults- large intestine lumen; 1-3cm; white
Eggs- strongyloid; 85um
L4- nodules in lg and sm intestine
Oesophagostomum spp
Life cycle of Oesophagostomum spp?
Typical strongyloid
Arrested L4 in sm or lg intestinal wall
Females lay large amount of eggs
Egg to L3 - 10days
What is the PPP of Oesophagostomum spp?
3-8wks
What are the sites of infection of Oesophagostomum spp?
Adults in lumen of large intestine
L4 in wall of sm or lg intestine (nodules)
What are the clinical signs of Oesophagostomum spp in ruminants and sows?
Ruminants: anorexia, diarrhea
Sow: anorexia, weight loss, reduced milk production (poor sow syndrome)
What is the treatment and prevention for Oesophagostomum spp?
Anthelmitics
Pasture management - transmission favored by high egg excretion, humid, and unhygienic conditions
Animals do not develop good immunity
What is the common name for Syngamus trachea?
Tapeworm
What are the hosts to syngamus trachea?
Domestic and wild fowl
PH- earthworm
What dis?
Bird
Adult -red in colour, found in Y (males and females)
Eggs- operculum at both poles
Syngamus trachea
What is the pathogenesis and clinical signs of the Gapeworm?
Asphyxia: mucus accumulates in trachea ->suffocation
Stomach worms and barber pole worms belong to what superfamily?
Trichostrongyloidea
What are the common characteristics of Trichostrongyloidea?
Thin stronglye
Direct, infective L3
Thin shelled, oval ,average size eggs
Arrested development
Males have a bursa
Cattle can develop stronger immunity against ________________ parasites then sheep or goats
Trichostrongyloidea
What worms are in the superfamily Trichostrongyloidea?
Stomach worms Barber pole worms Trichostrongylus spp Cooperia spp Lung worms Nematodirus spp
What is the brown stomach worms also called?
Ostertagia ostertagi
Who is the host of ostertagia ostertagi
Cattle
What is the site of infection for ostertagia ostertagi ?
Abomasum
PPP of ostertagia ?
21days / 3weeks
Pathogenesis of Ostertagia
Caused by L3 to immature adult in gastric gland
Thickened gastric musical with raised nodules = Moroccan leather
Increased plasma pepsinogen
What would be the diagnosis for calves in their first grazing season, with profuse watery diarrhea.
High morbidity but low mortality rates
Summer Ostertagiosis
What would the diagnosis be for calves following their first grazing season with intermittent watery diarrhea, bottle jaw, and high mortality rates
Winter Ostertagiosis
What do you used to diagnose Ostertagia ostertagi?
Clinical signs Season Grazing history Fecal egg count Culture and identify L3
Increased plasma pepsinogen level
Necropsy x_x
How do you treat and prevent Ostertagia ostertagi infections?
Type 1 - anthelmitics and safe pasture
Type2- anthelmitic against arrested L4 and adults
exposure is required to gain immunity
Hosts of Teladorsagia circumcincta
Sheep and goat
What is the pathogenesis and clinical signs of Teladorsagia circumcincta
Ostertagia in sheep and goats but not as bad
Weight loss
Diarrhea intermittent
What are the main differences between Ostertagia and Teladorsagia ?
Teladorsagia L3 does not survive on pasture as well as Ostertagia
Teladorsagia has PPR
Teladorsagia clinical signs are less severe
What is the common name for Hyostrongylus spp?
Stomach worm
What species is the host for Hyostrongylus spp?
Pig
Identify the parasite Pig Slender reddish nematodes 5-8mm long Trichostrongyloid eggs
Hyostrongylus spp
What is the PPP of Hyostrongylus?
3wks
What are the stomach worms of the superfamily Trichostrongyloidea?
Ostertagia -cattle
Teladorsagia -sheep/goat
Hyostrongylus - pig
What is the life cycle of Hyostrongylus?
Typical Trichostrongyloidea egg
L3 infective stage
L4-hypobiotic
PPR
What is the pathogenesis of Hyostrongylus?
Damage to gastric glands -> lower acidity and increased pespinogen
Mucosal hyperplasia “Moroccan Leather”
Nodule formation
Hemorrhage -> anemia
(Diarrhea not seen- unlike the other stomach worms)
What clinical signs would you see in an Hyostrongylus infection?
Inappetence
Loss of condition
Anemia
(No Diarrhea, usually)
What are the treatment and prevention methods for Hyostrongylus spp?
Outdoor pigs affected
poor sow syndrome
Anthelmitics
Similar treatments to ostertagia
Common name of haemonchus contortus?
Barber pole
Host of haemonchus contortus?
Sheep and goat
Identify the parasite Sheep Adults 2-3cm on abomasal surface Females -barber pole/striped red and white Eggs trichostrongyloids, 85um
Haemonchus contortus
What is the life cycle of Haemonchus contortus?
Typical strongylida life cycle
PPR
Hypobiosis
Site of infection of Haemonchus controtus?
Abomasum
What is the common name for Haemonchus placei?
Barber pole worm
What is the host for haemonchus placei?
Cattle
How do you diagnose haemonchus contortus?
Season History Clinical signs Fecal egg counts and Identify L3 Necropsy
What is the treatment for Haemonchus?
Anthelmitics - with resistance you must use an anthelmitic that works on that farm
Only treat the sheep/goats that require treatment- protect refugia
What is the host for Trichostrongylus spp?
Cattle, sheep, goat, equine
What are the sites of infection for Trichostrongylus spp?
Abomasum/stomach
Small intestine
What is the life cycle of Trichostrongylus spp?
Trichostrongyloids
Direct , infective L3
Low hypobiosis
What is the PPP of Trichostrongylus spp?
3-4wks
Host of Cooperia spp?
Cattle, sheep and goat
Site of infection of Cooperia spp?
Small intestine
PPP of Cooperia spp?
2-3wks
15-18days
What are the two most common nematodes f weanling age cattle?
Ostertagia and Cooperia
What is the pathogenesis and clinical signs of Cooperia?
Pathogenesis usually mild
Stressed cattle produce watery diarrhea
What are the lungworms?
Dictylocaulus spp
What is the diagnostic stage of Dictylocaulus spp?
L1 Baermann
Identify
Cattle
Adults -long thin, in bronchi
L1 found in Baermann
Clinical signs- coughing
Dictylocaulus spp
Host of Dictylocaulus viviparus
Cattle
Host of Dictylocaulus filaria
Goat and sheep
Host of Dictyocaulus arnfeldi
Equine
Life cycle of Dictylocaulus spp?
Adult -> egg -> hatch to L1
L1 coughed up and passed in feces
L1 develop to L3 -> ingested
L3 migrate to lungs via blood and mature
Pathogenesis of Dictyocaulus spp
Penetration phase: larval migrations- clinical signs not apparent
Prepatent phase: larvae develop to adults in lungs (alveolitis and bronchitis)
Patent phase: adult worms in lungs, bronchitis and pneumonia
Postpatent phase: relapse, entire lung diseased
Clinical signs of Dictyocaulus spp?
Bouts of coughing at rest
Postpatent parasitic bronchitis-dissolution and aspiration of dead or dying worms
Treatment and prevention of Dictyocaulus
Anthelmitics
Management
Avoid endemic pastures
Develop immunity with age
Vaccination (europe)
How does Dictyocaulus infection differ in donkeys and horses?
Donkey - adapted, few clinical signs
Horse- rarely reaches sexual maturity, damage to pulmonary tissue, chronic cough.
What is the common name of Nematodirus spp?
Long neck bankrupt worm
Host of Nematodirus spp?
Sheep, goat, cattle
Identify
Sheep
Adults large 2.5cm
Eggs very large 130um
In sheep, goat, and cattle
Nematodirus
Site of infection of Nematodirus
Small intestine
Life cycle of Nematodirus?
L1 to L3 ALL inside egg (2months)
L3 can survive up to a 2 years in egg
Hatched L3 consumed -> small intestine
Adult- >egg
PPP of Nematodirus spp?
3 weeks
Nematodirus requires what for the L3 to emerge from its egg?
Freeze and thaw
-> large numbers emerge at the same time, usually in spring
Lamb to Lamb disease
Pathogenesis and clinical signs of nematodirus?
Larvae interrupts intestinal mucosa
Sudden onset of ill thrift in lambs
Severe diarrhea
Morality up to 30%
What can make Nematodirus diagnosis challenging ?
Clinical signs prior to PPP
Egg count of little value
Treatment and prevention of Nematodirus infection
Avoid pastures used the previous year in spring/early summer
Prophylactic treatment; predictions
True or false: Resistance to one drug in a class confers resistance to all others
True
What is the best way to manage parasites without promoting anthelmitic resistance?
Animals will not be parasite fee
Prevent clinical disease and production losses
Maintain below economic threshold
What is the economic threshold in relation to parasites?
Density of a pest at which a control treatment will provide an economic return
Point where loss is > the cost of treatment
What are strategies that decrease refugia?
Treating and moving to a clean pasture
Treating when there are FEW larvae on pasture
Treat ALL animals
Anthelmitics with residual activity
In what two ways can breeding strategies contribute to parasite management ?
Resistance - animal can control parasite population
Resilience - animal can better tolerate infections
What are the general characteristics of parasites in the superfamily Metastrongyloidea?
Indirect life cycle
IH snail or slug
L1 diagnostic stage (kinked posterior end)
What is the common name of Muellerius spp?
Lung worm
What are the hosts of Muellerius spp?
Sheep and goat
IH: molluscs
Identify
Sheep
Adult - embedded in lungs
L1 S- shaped kink
Muellerius spp
Life cycle of Muellerius spp?
L1 in feces -> penetrate foot of mollusk
Develop to L3
Sheep ingest L3
L3 migrate to lungs
Develop to adult in lymph nodes and nodules in lungs
Site of infection of Muellerius spp?
Lungs
Nodular lesions looks and feels like “lead shot” in lung tissue
Muellerius spp
How do you treat and prevent Muellerius infections
Anthelmitics
Control of L3 difficult because they can live as long as mollusk is alive
Parelaphostrongylus tenuis hosts?
White tailed deer
Abberent: equine, sheep, goat, llama, camel
IH: molluscs
What is the common name of Parelaphostrongylus tenuis?
Meningeal worm
Parelaphostrongylus tenuis causes what disease in its abberent hosts?
Invade nervous tissue and cause neurological disease
Fatal
Not patent
Metatrongylus spp common name?
Pig lungworm
Hosts of Metastrongylus spp?
Pig
IH: earthworm
Identify Pig Slender white worms 6cm Small eggs with L1: irregular exterior Larger than Strongyloides spp
Metastrongylus spp
PPP of Metastrongylus spp?
4wks
What is the site of infection of Metastrongylus?
Bronchi and bronchioles
Pathogenesis and clinical signs of Metastrongylus spp?
Lung migration-> lesions
Bronchitis and coughing
Secondary infections
How do you diagnose Metastrongylus spp?
Eggs with L1 in fecal
Treatment and prevention of Metastrongylus spp?
Long lasting exposure due to earthworm reservoir
Young severely affected
Outdoor pigs have higher contact with earthworm
Aelurostrongylus abstrusus common name?
Cat lung worm
Hosts of Aelurostrongylus abstrusus?
Cats
IH: snails and slugs
PH: bird, rodent, and frogs
Identify
Aggregation of parasite in lung tissue of cat
L1 with kinked tail in feces
Aelurostrongylus abstrusus
Life cycle of Aelurostrongylus abstrusus
L3 ingested -> migrate to lungs
Females lay nests of eggs -> small gray nodules in lung parenchyma
L1 hatch -> coughed up and swallowed -> feces
L1 ingested by molluscs and develop to L3
PH ingest IH
Cat ingest PH
Site of infection of Aelurostrongylus abstrusus
Lung parenchyma and bronchioles
Clinical sign of Aelurostrongylus abstrusus?
Chronic mild cough
Prevention of cat lungworm infection
Prevent access to IH and PH
French heartworm also known as?
Angiostrongylus vasorum
Common name of Filaroides (oslerus) osleri?
Tracheal worm
Host of Filaroides and Angiostrongylus ?
Dogs and wild carnivores
Filaroides osleri life cycle?
Direct
L1 ingested, develop in lung
Female lay eggs with larvae
L1 hatch, expelled inundated sputum or pass in feces
(Doesn’t need an evnornmental stage -> mom to pups )
Identify
Dog
Nodules detected with bronchoscope
L1 with kinked tail in feces or sputum
Dog
Filaroides osleri
Treatment and prevention of Filaroides osleri?
Benzimidazoles reduce level
Persistent problem in kennels
PPP of Filaroides osleri
6-7months
Common lungworms found in dogs
All causing cough and exercise intolerance
Filaroides osleri
Filaroides hirthi
Angiostronylus vasorum
Crenosoma vulpis