Worm Map 2019 ❤
Nematoda
Strongylida
Strongyloidea
(horse strongyles)
Large-bodied
Copulatory bursa
Buccal capsules
Direct life cycles
Migration
Strongyle-type eggs
EXCEPT Syngamus
(bioperculated)
Large Intestine
Except Stephanurus and Syngamus
Syngamidae
Syngamus trachea
(gape worm) (birds)
Trachea of domestic birds
Adult worms in trachea
L3 develops inside egg
Ingestion of egg
Ingestion of L3
Paratenic host
Penetrate GI and go to lungs
PPP 18 days
Pathogenesis
Hemorrhagic tracheitis
Gaping
Coughing, shaking
(young birds —> death)
Stephanurus dentatus
(swine kidney worm)
L3 develops in egg
Ingestion of L3
Paratenic host
Faculative intermediate host
(some dev occurs
L4 migrates to liver
From liver to kidney
Eggs passed in urine
Pathogenesis
L4: severe cirrhosis
Adult: inflammation & thickening of kidney
Green pus in kidney
Chabertiidae
Oesphagostomum
Oesophagostomum dentatum
(pigs)
Oesophagostomum radiatum
(ruminants)
Adults in colon
Free-living larval development
Can survive winters
Ingestion of exsheathed L3’s
Penetrate mucosa of SI/LI
Can undergo hypobiosis
PPP 28-42 days
Pathogenesis
L3 nodules
L4 —> ulcers
Enteritis
Anemia, protein loss, weight loss
Heavy: chronic UC
Inappetence & emaciation
Strongylidae
Strongylinae
Large strongyles
Genus Strongylus
Strongylus vulgaris
(horses and donkeys)
L4 migrate to endothelium in cranial mesenteric artery
Molt to L5 (2-3 mo)
Return to intestine via arterial lumen
Strongylus equinus
(horses and donkeys)
Strongylus edentatus
(horses and donkeys)
Common threads
Adults live in cecum
Eggs pass in feces
Penetrate intestinal mucosa
Nodules form in the mucosa
Burst & release adults
Cyathostominae
Small Strongyles
Ancylostomatoidea
(hookworms)
Bent head
Oral cutting plates (teeth)
Pathogenic mechanism = hematophagy
Bunostominae
(cutting plates)
Bunostomum phlebotomum
(cattle)
Oral or through skin
Tracheal migration
Accidental infections of humans
L3 infectious
Hypobiosis - seasonality
Cattle
Ancylostominae
(cutting buccal teeth)
Ancylostoma caninum
(dogs and cats)
Skin, oral, transmammary transmission
(only transmammary hookworm in dogs/cats)
PPP 14-21 days
L4’s can feed
Most pathogenic
Susceptibility declines with age
Ancylostoma tubaeformae
(cats)
Ancylostoma braziliense
(dogs and cats)
Trichostrongyloidea
Trichostrongylidae
Haemonchus
Periparturient Rise in summer/fall
Sheep, goats, and other ruminants
Symptoms
Chronic
Weight loss
Lethargy
Mild anemia
Edema +/-
Acute
Anemia (pale MM)
severe edema
weakness, wool loss
sudden hemorrhagic death
dark feces
NO DIARRHEA
No effective vaccines
Refugia treatment - treat only most affected animals
Ostertagia
Signs
Profuse & watery diarrhea
Anorexia / dehydration
weight loss
sub-mandibular edema
Low grade anemia
Diagnostic nodules
Ostertagia ostertagi - cattle
Ostertagia circumcinta - sheep
larvae grow in gastric glands
Seasonal
Diagnose with plasma pepsinogen
2 clinical entities
Type I
Young cattle, contaminated pastures
Type II
Arrested L4 erupt from glands
Trichostrongylus
Trichostrongylus colubriformis
Sheep, goats, llamas, cattle
Small intestine
Mucosal disruption
distort and flatten villi
Protein loss and diarrhea
Trichostrongylus axei
Ruminants, horses, pigs
Abomasum, stomach
Erode glandular epithelium, nodules
Cooperia
Affects abomasum/SI
Nematodirus
Ollulanidae
Ollulanus
Dictyocaulidae
Dictylocaulus viviparus
lay eggs in lungs
No eggs in feces - L1s
Coughing, tachypnea, dyspnea
Seasonal
Vaccine in Europe
filaria - sheep
arnfieldi - equine
Small, hair-like
Large copulatory bursa
small buccal capsule (pathogenesis)
Abomasum, stomach, small intestine
Ascaridida
Ascarids
Small Animals
Toxacaris leonina
dogs & cats
No tracheal or somatic migration
No prenatal or transmammary transmission
Toxacara canis
dogs
Eggs passed in feces
2 weeks - larvae mature in egg & become infectious
7 year persistence
Paratenic rodent or bird
Lighter infection
PPP 4-5 weeks
Large burden - obstructions
Diagnosis
Respiratory signs
Pot belly / abdominal distress
Baylisascaris procyonis
raccoons & dogs
Somatic migration
Large, neurotrophic larvae
Zoonotic
Toxacara cati
cats
No prenatal transmission
PPP: 5.5-8 weeks w/ egg ingestion
Paratenic rodent
PPP: 3 weeks, no migration o/s GI tract
Large Animals & Poultry
Ascaridia galli
(chickens)
Small intestine
No tissue migration
Small intestine damage/absorption issues
Subulroidea
Heterakis gallinarum
Vector of: Histomonas meleagridis
(a protozoa)
Parasite of cecum and liver
Very deadly
Turkeys worse than chickens
Chickens are reservoir hosts
Cecum
Reduction in egg production
Ascaris suum
(swine)
Direct or earthworm transfer host
(Mixed life cycle)
Life cycle is the same
PPP: 3-6 weeks
SI -> penetrates wall -> portal vein -> liver
L3 -> heart -> lungs -> bronchi -> trachea -> SI
Tracheal migration
Hatch in temperature dependent fashion
Pathogenesis
Milk spot lesions on liver
Lungs - pneumonia and cough
Diarrhea, weight loss (SI)
Rarely: intestinal obstruction
Parascaris equorum
(horses)
PPP: 10-12 weeks
Tissue migration
Liver: no white spots
Lungs/bronchi: pneumonia, nasal discharge, coughing
SI: rare, impaction, peritonitis, death
Long-lived eggs
Toxocara virtulorum
(young calves)
Rare in NA
Transmammary transmission
Zoonotic
Only migrate in adults (not calves)
Oxyurida
Pinworms
Oxyuris equi
PPP: 4-5 months
Cecum and colon
Eggs on the perianal skin - irritation
L4: feed on mucosa of colon
erosion, ulcers
Adults feed on intestinal contents
Eggs: slightly flattened on one side - plug on one end
Syphacia obvelata
S. muris
Aspiculuris tetraptera
(rats and mice)
Passalurus ambiguus
(rabbits)
Enterobius spp.
(chimps and humans
Probstmaryia vivipara
(horses)
Stichosomida
Trichuroidea
(superfamily)
Trichuris
whipworms
T. suis
(swine)
PPP: 41-47 days
Direct life cycle
Signs
Profuse diarrhea
Anorexia, dehydration, emaciation
Growth retardation
Survive for years in soil
T. vulpis
(dogs)
PPP: 70-90 days
Mature in 1 mo and survive years
Clinical signs w/ heavy infection
Profuse diarrhea
Straining
Rarely anemia and death
Can pick up from dog parks
T. ovis
(ruminants)
Non-pathogenic
T. trichiura
(simian primates)
Pathogenic
Capillaria
Dogs, cats, foxes
C. boehmi
(frontal nasal sinus)
PPP: 40 days
Runny nose, sneezing
C. aerophila
(bronchi)
PPP:30 days
Coughing, dyspnea
C. plica
(urinary bladder)
PPP: 60 days
Hematuria, dysuria, pollakuria
Birds
C. contorta
(crop and esophagus)
Ruminants
C. bovis
(small intestine)
Rodents
C. hepatica
(liver)
Bipolar-plugged eggs
Earthworms
Trichinella
Trichinella spiralis
Newborn larvae migrate to muscle cells
Encyst in muscle as L1
Larvae digested out of meat/muscle fiber
Signs
Loose stool & vomiting
Weakness
Muscle stiffness & discomfort
Trichinella murrelli
Trichinella nativa
(Arctic)
L1 not encapsulated in muscle
Trichinella pseudospiralis
(wildlife and birds)
Enoplida
Cioctophyma renale
(Giant Kidney Worm)
Right kidney or abdominal cavity
Rhabditida
Strongyloides spp.
Small, thin-shelled embryonated egg
Ingestion or skin penetration
Transmammary transmission
S. stercoralis
(dogs & primates)
Autoinfective - reproduction w/i definitive host
Direct / indirect life cycle
PPP: 10 days
No mouth capsule
Migration to gut
Genital primordian
S. papillosus
(sheep)
Common in young animals
Transmammary transmission
PPP: 1 week
S. vituli
(cattle)
S. ransomi
(swine)
PPP: 9 days
transmammary transmission
Severe liquid diarrhea
S. westeri
(horses)
PPP: 14 days
Transmammary transmission
Wasting - severity of diarrhea
Pathogenesis
Due to larval penetration
Due to migration
Due to adults in intestines
Migration after autoinfection (stercoralis)
Pelodera strogyloides
Skin / hair follicle
Cattle, dogs, humans, rodents
No FDA approved drugs
Rhabditis bovis in cattle - otitis externa
Loss of fur, very itchy
Halicephalobus gingivalis
facultative parasite (horses, humans)
Ulcers around gums
Parthenogenic
Opportunistic pathogens
Metastrongyloidea
(lungworms)
No buccal cavity
Located in lungs / adjacent vessels
Carnivores, ungulates, rodents, and primates
Mostly indirect lifecycles - slugs
L1 in feces - kinked tails
Metastrongylus apri
(swine)
Inhabits bronchi, bronchioles, posterior lung
Eggs laid in bronchi, coughed up -> feces
L1 hatch in feces - may be directly or indirectly infective
L3 liberated from wall of esophagus
Lymph nodes, blood, and lungs
PPP: 4 weeks
Pathogenesis
Bronchitis and bronchiolitis
Enlarged mesenteric lymph nodes
Pigs in pasture
Poor growth, nasal discharge
Levamisole, Fenbendazole, Ivermectin
Protostrongylus rufescens
(sheep and goats)
Embedded in smallest broncioli
Snail/slug intermediate host
L1 hatches in bronchioli / in feces
Transmission:
Snail -> sheep, molt in mesenteric lymph node, through bloodstream to heart & lungs
PPP: 5-6 weeks
Transplacental transmission
No pathognomic signs
Morbidity and mortality in Big Horn Sheep
Ivermectin, Moxidectin, Doramectin, Fenbendazole, Albendazole
Muellerius capillaris
(sheep and goats)
Alveoli, not bronchioles
Slugs and snails = int hosts
Temperate regions
Highly pathogenic in goats
L1 in feces - kinked tail
Moxidectin - adults
Eprinomectin - topical for goats
Parelaphostrongylus tenuis
(cervids, camelids, sheep)
Brain worms
Adults in cranial venous sinuses & subarachnoid spaces (CNS)
Persistent infections - ~4 years
Non pathogenic in deer
Snails/slugs
Molt twice w/i intermediate host
PPP: 3 months
(migration to spinal cord: 10 days)
CNS signs
Fenbendazole PO, Ivermectin SQ
Aelurostrongylus abstrusus
(cats)
5% of cats
Male has short bursa
Eggs into alveoli - egg masses form nodules
Penetrate terrestrial mollusk, molt twice to L3
Reptiles, rodents, or birds are paratenic hosts
Usually slight
Heavy infection: chronic cough, gradual wasting, dyspnea, death
Resp signs are due to embolism of alveolar vasculature and mechanical irritation
Imidacloprid & Moxidectin single topical dose
IVM injected SQ
Angiostrongylus vasorum
French Heartworm
(dogs/wild canids)
Pulmonary arteries, right ventricles
Smaller than D. immitis
Eggs released in pulmonary circulation
L1 coughed up and passed in feces
Subclinical to fatal signs
Cardiorespiratory signs
Hemorrhage from L1 eruption
CNS disease
Interstitial pneumonia
Milbemycine oxime PO
Post-treatment complications - dyspnea & ascites
Filaroides (Oslerus) osleri
(dog)
Direct lifecycle (infective L1)
Ovoviviparous
Ingestion of regurgitated stomach contents, feces, or tissues containing L1s
PPP: 6-7 months
Signs
Tracheobronchitis (can be confused with kennel cough)
Spastic, hard, dry cough @ exercise or cold air
Gray or pink nodule @ bifurcation of trachea
Found at bifurcation of trachea
Fenbendazole or ivermectin
Crenosoma vulpis
(raccons & foxes)
Bronchi and broncioles
Ovoviparous female
L1 exits with feces and develops into L3 inside snails/slugs
No direct transmission
Milbemycin oxime, Imidacloprid+Moxidectin, FBZ
Spiruroidea
Viviparity
No GI tract predilection sites
Arthropod int host/vector
Spirocerca lupi
Esophageal nodule w/ adult worms
Eggs in feces (paperclip eggs)
Coprophagous beetles ingest eggs
L3s migrate up celiac a.
Burrow out of aorta & move to esophagus
Lesions in aortic lining
PPP: 6 months
Metastatic osteosarcoma in lung
Spondylosis - mitogens cause abnormalities in spinal column
Gongylonema sp.
(esophagus of cow)
Long, red adult worms like squiggles
No giant nodules
Egg in fecal floatations
Physaloptera rara
(stomachs of dogs and cats)
Adults in stomach of host
Usually asymptomatic
Dracunculus insignis
(raccoon) - guinea worm
Copepod vector (waterborne arthropod)
Ruptures cyst and adult worm extrudes
Put paw in water and worm lays eggs
Draschia megastoma or Habronema
(horses)
Flies get larvae on mouth parts, land on animals and feed to infect
Muzzle or eyes of horse (anything chronically wet)
Skin lesions on horse - non-healing cutaneous lesions
Thelazia californiensis
(many species) - Eye worm
Release eggs into tears
No GI tract
Filaroidea
No cephalic armature
Extrinsic dev required
Microfilariae - specialized transitional life stage
Undifferentiated prelarvae
Released into tissue
Infective stages for arthropods
Onchocerca cervicalis
(horses)
From eyes
Microfilaria in skin section
Setaria equina
(horses)
Peritoneal cavity as adults
Dirofilaria immitis
Mosquito vectors (Culicidae)
L3 transmitted 2 wks after dev in mosquito
Malpighian tubules
Signs
Coughing
Labored breathing
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Wolbachia endosymbionts (LPS issues)