Unit 3 - Nematodes Flashcards
Physaloptera spp. affects what species?
felids, canids
stomach worm
Physaloptera
What is the US distribution of physaloptera?
most common in midwest
DH of Physaloptera:
canids and felids (also variety of wild carnivorous mammals, including coyotes and foxes)
PPP of Physaloptera:
~44-83 days; different species
What stage of Physaloptera is in feces?
larvated eggs
What is the infective stage of Physaloptera?
L3
Where does L3 of Physaloptera attach?
to the stomach
Where are the adult Physaloptera located in the host?
stomach
What is the IH for Physaloptera?
beetles, cockroaches, crickets
What is the PH for Physaloptera spp?
amphibians, reptiles, mammals (have to ingest IH first)
How do DH become infected with Physaloptera?
ingestion of PH/IH with L3
List the pathogenesis seen with Physaloptera adults?
- attach to mucosa
- feed on blood and mucosa
- ulceration
- hemorrhage
- catarrhal gastritis
Physaloptera spp. clinical signs:
usually asymptomatic
What is the primary way to differentiate between ascarids and Physaloptera?
ascarids are found free in the stomach while physaloptera are attached to the mucosa
While Phylasoptera eggs are not usually found on fecal flotation, instead you should use:
fecal sedimentation (easy to miss)
Effective treatment for Physaloptera is difficult and often involves these three things:
- limit exposure
- removal of nematodes via endoscopy
- repeated tx of antihelmintics
Dracunculus insignis affects what species:
raccoons, mink, canids (felids are rare)
Dracunculus insignis can be found across North America, but infections are:
rare
PPP for D. insignis:
~200 days
DH for D. insignis:
racoons, minks, canids (felids - rare)
Which stage of D. insignis is released into the water?
L1
How do DH become infected with D. insignis?
ingestion of PH/IH with infective L3 in water
L3 for D. insignis goes to the:
thoracic and abdominal muscles
Once D. insignis matures to its adult stage, the females move to the:
SubQ extremities
IH for D. insignis:
copepods (water fleas)
PH for D. insignis:
frogs
D. insignis pathology and clinical signs:
- pyogranulomatous inflammation
- chronic nodules or abscesses (~ 2 in. on limb and abd)
D. insignis diagnosis:
removal of adult from nodules
Which nematode species affect equids?
Draschia & Habronema spp
IH for Draschia and Habronema spp.:
Musca domestica (house flies) Stomoxys calcitrans (stable flies)
Which is the most important IH for Draschia and Habronema (in US)?
house fly
Which stage of the Draschia and Habronema spp. are in equid feces?
L1
Which stage of D & H is transferred to the DH?
L3 (infective stage)
All stages of D & H spp. are in the stomach except the eggs which:
hatch in the GI tract
How do flies get infected with D & H species?
ingest L1 from DH feces
How do flies transfer D & H L3 to DH?
Fly feeds on horse; horses ingests fly or licks and ingests L3
Draschia and Habronema spp. pathogenesis:
- tumor like lesions near margo plicatus
- fibrous nodules filled with pus-like material in which the worms live
Draschia adults are found:
in tumors close to margo plicatus
Habronema adults are found in:
glandular portion of stomach
Draschia and Habronema clinical signs associated with adults:
- usually asymptomatic
- gastritis
- perforation
- peritonitis
Draschia and habronema clinical signs associated with larvae:
- granulomatous lesions
- cutaneous (summer sores)
- both D & H species
D&H diagnosis:
- eggs: PCR
- Larvae: lesions
- Adults: necropsy
esophageal worm
Spirocerca lupi
What species does Spirocerca lupi affect?
domestic and wild canids, wild felids (rare in domestic cats)
PPP for Spirocerca lupi:
4-6 months
What stage of Spirocerca lupi can be found in DH (cats, dogs) feces?
larvated eggs
How do DH become infected with Spirocerca lupi?
ingests PH/IH with infective L3
What does L3 of Spirocerca lupi do once it is ingested by the DH?
- penetrates gastric wall
- L3 walls of gastroepiploic & gastric artery –> celiac artery –> thoracic aorta –> L4 –> adults
Where do the adult Spirocerca lupi migrate to?
- connective tissue
- found in nodules in esophageal wall, stomach
What is the IH for Spirocerca lupi?
- coprophagous beetles (dung beetles)
What is the PH for Spirocerca lupi?
mammals, birds, lizards, toads
Spirocerca lupi pathogenesis:
- aortic aneurysms, thrombosis
- granulmoas/sarcomas in esophagus
Spirocerca lupi clinical signs (5):
- esophageal dysphagia
- vomiting
- esophogeal neoplasia
- aortic aneurysm or rupture
- thickening of long bones (hyptertrophic osteopathy)
Idenitification of spirocerca eggs can be done via:
- fecal flotation
- vomitus
Identification of Spirocerca lupi adults can be done via:
- vomitus
- necropsy
Oxyuris equi affects what species:
equids
pinworms
Oxyuris equi
PPP for Oxyuris equi:
4-5 mos
Infective stage of Oxyuris equi:
L3 in egg
Only the female moves to the anus of the equids. Why?
lay eggs in gelatinous substance (“cement”) under tail
Which adult stage of Oxyuris equi is of primary importance in pathology?
egg-laying females (inflammation of colon and rectum)
Oxyuris equi diagnosis:
- presumptive: clinical signs
- definitive: “scotch tape method”
Filarids in the order Spirurida have what type of life cycle?
indirect
What is the intermediate host for filarids?
blood sucking arthropods
Ochocerca cervicalis infects what species?
equids
What is the IH for Onchocerca cervicalis?
generally culicoides spp (ie biting midges)
PPP for Onchocerca cervicalis:
~16 months
How do L3 infect the DH?
next blood meal of IH
L3 for Ochocerca travels to the:
nuchal ligament (also L4 and adults)
What causes Onchocercal dermatitis?
antigen released from dying microfilaria (causes pathogenesis)
To diagnose Onchocerca cervicalis, you must:
perform a full-thickness skin biopsy (> 6 mm)
What is a differential for Onchocerca cervicalis?
hypersensitivity reaction to biting flies
What is used to treat Onchocerca cervicalis?
- NO TX for adults
- ivermectin efficacious against microfilariae
Onchocerca lupi affects:
canids
DH for Onchocerca lupi:
dogs, cats
Canine onchocercosis is associated with pathogenesis in/around the:
eye
DH for Acanthocheilonema reconditum?
Dogs
Life cycle for A. reconditum:
indirect
PPP for Acanthocheilonema reconditum?
2-3 mos
IH for A. reconditum:
fleas (C. felis, C. canis, P. irritans)
A. reconditum clinical signs?
generally nonpathogenic
Since A. reconditum is nonpathogenic, why is it important?
differentiating its microfilaria from D. immitis (heartworms)
DH for dirofilaria immitis:
domestic dog, domestic cat (much lower prevalence)
IH for Dirofilaria immitis:
mosquitoes
No larval development of D. immitis occurs in the temperature is below:
14 C
Late stage pathogenesis for HWs:
- heart may enlarge and become weakened
- CHF
Where do nearly all heartworms reside?
in lower caudal pulmonary arteries
What medicines are effective against L3 and L4 and the elimination of microfilariae on Dirofilaria immitis?
macrocyclic lactones (ivermectin, milbemycin, etc.)
Caval syndrome is an acute disease/clinical emergency characterized by:
- large number of worms
- increased venous pressure in liver
Caval syndrome clinical signs:
- acute weakness/anorexia
- dyspnea
- collapse
- pale mucous membranes
- bilirubinemia
- bilirubinuria
- hemoglobinuria
PPP of heartworms in cats?
7-8 months
Where are heartworms located in cats?
pulmonary artieries and right heart
When adult heartworms die in cats,it can lead to:
- inflammation
- thromboemboli
- infarction
- respiratory failure possible
With heartworms, cats are:
rarely microfilaremic
- also rare to find any circulating
Intracellular gram-negative bacteria:
Wolbachia pipientis
Why do we need to know about Wolbachia pipientis?
Necessary for Dirofilaria immitis to reproduce/thrive
Primary tx for heartworms:
doxy
What is a periparturient rise?
- relaxation of immunity due too increases in prolactin
- rise in nematode egg counts in the feces of lactating ewes or does at weaning
What are three important characteristics of Trichostrongyles?
- common
- high significance
- primarily ruminants
Parasitic Gastroenteritis (PGE) of ruminants has dramatic production (and thus economic) losses when disease is:
subclinical
What are some common symptoms of subclinical PGE?
- watery, green diarrhea
- submandibular edema
What are some causes for arrested larval development (ALD)?
- seasons
- climate
- immune response
- overcrowding
A susceptible parasite gene pool not exposed to a particular control measure (escapes selection for resistance)
Refuge
What are some integrated pest management protocols for controlling ruminant strongyles?
- pasture rest/rotation
- multi-species grazing
Ostertagia ostertagi host:
cattle
Ostertagia ostertagi adult site:
abomasum
O. ostertagi PPP:
18-21 days
Where does the L3 (infective stage) of Ostertagia ostertagi go?
burrows into gastric glands in pyloric and fundic regions of abomasum
Of major importance in cattle:
O. ostertagi
When and where can O. ostertagi arrest?
L4; abomasal glands
Ostertagiosis pathogenesis is associated with _______ _______and __________ NOT feeding behavior.
larval growth and development
What is the name of the lesion seen in the abomasum in association with Ostertagiosis?
cobblestone lesions
What are the clinical signs of Ostertagiosis (4)?
- diarrhea
- weight loss (emaciation)
- dehydration (thirst)
- submandibular edema (hypoproteinemia)
Teladorsagia circumcincta host?
sheep/goats
Teladorsagia circumcincta adult site?
abomasum
Which ruminant strongyle is a contributor to PGE via diarrhea and weight loss?
Teladorsagia circumcinta (goats, sheep only)
Haemonchus placei host:
cattle
Haemonchus placei adult site:
abomasum
Haemonchus placei PPP:
23-32 days
Haemonchus contortus host:
sheep, goats
Haemonchus contortus adult site:
abomasum
Haemonchus contortus PPP:
18-21 days
Haemonchus spp. can:
arrest
L3, L4, and adults of Haemonchus spp. feed on:
blood
Where do the L3 of Haemonchus go?
exsheath in rumen and move to abomasum near glands
Because Haemonchus species are blood feeders, what are some common clinical signs for hyperacute, acute, and chronic Haemonchosis?
anemia, skin pallor, pale mucus membranes
What are some GENERAL clinical signs for Haemonchosis?
- bottle jaw
- dark feces
- death (before patency possible)
Trichostrongylus axei host location:
- abomasum in ruminants
- stomach in horses
Trichostrongylus axei host:
horses, cattle
Trichostrongylus axei PPP:
14-21 days
T. colubriformis host:
ruminants
T. colubriformis location in host:
small intestine
T. colubriformis PPP:
18-20 days
Often asymptomatic contributor to PGE; ALD:
Trichostrongylus spp.
Trichostrongylus species can have massive infections known as:
“black scours”
Cooperia spp. that affect cattle:
- onchophora
- punctata
- pectinata
- sumabada
Cooperia spp. that affect sheep:
- sumabada
- curticei
Cooperia spp. that affect goats:
curticei
All Cooperia spp. adults go to the:
small intestine
Cooperia spp. PPP:
13-19 days
Oesophagostomum radiatum host:
cattle**
Oesophagostomum columbianum host:
sheep and goats
Oesophagostomum spp. adult site:
large intestine
Oesophagostomum spp. PPP:
28-41 days
Oesophagostomum pathology/signs:
- hemorrhagic/purulent nodules
- mucus
- leakage of blood and plasma proteins
Diagnosis of ruminant strongyles can really only be done through:
- culture and identification of L3
- identification of adults at necropsy
Nematodirus spp. adult site:
small intestine
Nematodirus spp in cattle:
helvetianus
Nematodirus spp in sheep:
- battus
- filicolis
- spathiger
What’s important about the pasture larvae of Nematodirus spp?
resistant to drying and freezing
Equine strongyles are broken into two groups:
- Strongylinae (large)
2. Cyathostominae (small)
Has ear shaped teeth and can be up to 2.4 cm long:
Strongylus vulgaris
Has one large tooth and two smaller teeth
Strongylus equinus
Has no teeth but can be as long as 4.5 cm
Strongylus edentatus
Host for Strongylus vulgaris:
horses, donkeys, mules, zebra
Where does the L4 of Strongylus vulgaris migrate to in the body?
cranial mesenteric artery
What is the infective stage of Strongylus vulgaris?
L3
PPP for Strongylus vulgaris:
6-7 months
Strongylus vulgaris migrating larvae can cause what pathology?
- arteritis**
- thrombi
- emboli
- intestinal nodules (adults emerge from these)
Primary clinical sign associated with S. vulgaris regardless of age:
anemia
S. vulgaris acute syndrome:
- infarction and necrosis of intestine
- damage to smooth endothelial surfaces
- inflamed/thickened arterial walls
- thromboemboli (cranial mesenteric)
Strongylus equinus host:
horses, donkeys, mules, zebras
Where do the L4 of strongylus equinus go?
liver, pancreas (3-4 months)
Strongylus equinus PPP:
~9 months
S. equinus pathology:
- mainly due to larvae*
- hemorrhagic nodules in intestines
- nodules, fibrotic tracts in liver
- nodules in pancreas
Strongylus edentatus host:
horses, donkeys, mules, zebras
Where does the L4 of S. edentatus travel to?
liver, hepatic ligament, parietal peritoneum; right flank
PPP for S. edentatus:
~6-11 months
Describe the pathology caused by Strongylus edentatus:
- Mainly due to larvae**
- perivascular thickening
- subperitoneal cysts
- nodules and fibrous tissues
Specific signs for S. vulgaris:
- high fever
- inappetence
- colic (intussesception, cranial mesenteric artery)
Diagnosis of large strongyle infections:
fecal float and detection of strongyle-type eggs
Which stage of small strongyles (cyathostomes) can arrest? Where?
L3; Crypts of Leiberkuhn
Small strongyle pathology:
- larval cyathostomes in colon wall
- hemorrhagic nodule formation
What is the most pathological event of small strongyles?
L4s emerging from tissues
What are small strongyles in comparison with large strongyles?
less severe