Order Oxyurida and Spirurida Flashcards
What are the general features of Order Oxyurida?
Known as pinworm Direct lifecycle Hosts - humans and horses Reduced pathogenicity Eggs are asymmetrical Oesophagus contain posterior bulb Females have pointed tail Males are smaller than females Males have single spicule transmission via ingestion of L3 egg
What are the main features of the oxyuris equi species?
Infect horses
Adults located in large intestine
L4 feed on mucosal tissue and blood
Posterior end of females are pointed and males is pin shaped
Efggs are thick shelled, one cell with a mucousal plug and asymmetrical.
Eggs laid in perianal region of horses which contain morula or larvae
What is the lifecycle of oxyuris equi?
Infection via embryonated eggs with food (pasture, hay, etc)
Females migrate to the anus and emerge into the enternal environment
The females lay many eggs embedded in a viscous substance which adheres the eggs to the perianal region
Will see yellow / grey crusts
Makes the horse itchy and will scratch against a pole and spread the eggs
Larvae development within the eggs
What is another species from oxyuria?
Probstmayria vivipara
what are the two superfamilies of Spirurida?
Superfamily Spiruroidea
Superfamily Filarioidea
What are the main features of Spiruroidea?
Wide range of shapes
Posterior end of males are spirally coiled
Mainly Oviviparous (eggs contain L1)
Indirect lifecycle –> IH infection, ingestion of IH by DH
What are the main features of Draschia megastoma?
Within horses
Adults in stomach, larvae within conjunctiva, skin and lungs –> form nodules
No teeth
Buccal vestibule (funnel shaped –> wider anterior and smaller cylindrical part)
2 lips
Eggs contain larvae that hatches quickly
IH = muscid flies
What is the lifecycle of Draschia megastoma?
IH = flies
Females lay embryonated eggs, eggs/larvae passed in faeces
Worm larvae ingested by fly larcae
L1-L3 within fly
L3 reaches the mouthparts f the fly and when it feeds on the moist, warm surfaces of the horse, the larvae are stimulated and leave the fly
The larvae can be deposited around the mouth of the horse –> develop into adults in the stomach and cause gastric habronemosis
The larvae can also be deposited in wounds, perocular area, penis, prepuce, nostrils, etc –> cause severe pathology (no larval development) –> causes cutaneous / pulmonary habronemosis
What are the main features of spirocerca lupi?
Hosts –> dogs
Adult parasites within the wall of the oesophagus and causes nodules
Immature stages can be within the stomach and dorsal aorta
IH = dung bettles
Eggs are ingested by IH, DH ingest infected IH. L3 released in stomach, reach aorta and migrate to oesophagus
What are the main features of Gnathostoma spp.?
Within pigs, dogs / cats
PH = humans
thick worm
Anterior end has a cuticular swelling (doughnut) covered with rows of hooks
Body is covered in spines
Eggs have thickening at one or both poles of shell
Contain 2 IH = copepods and fish
Eggs passed in faeces, Develop in water and larvae hatch
Ingested by copepods, copepods ingested by fish, larvae molt to L3, DH ingests infected fish, mature in stomach and form nodules / ulcers
Humans can become infected by consuming raw freshwater fish containing L3 - VLM and OLM, do not mature
What are the species of gnathostoma which infect the host?
Gnathostoma hispidum - stomach of pigs
Gnathostoma spingerum - stomach of dogs and cats, PH = humans
What are the main features of Thelazia rhodesi?
Within ruminants and buffalo Located in the conjunctival sac and lacrimal (tear duct) White worms Striations No lips Wide vestibule IH = flies Female worms lay larcae into lachrimal secretions, ingested by IH, L3 develops and migrates to mouth parts, transferred to DH when feeding around eyes
What are the main features of Thelazia callipaeda?
Hosts - dogs, cats, foxes, humans
Located in conjunctival sac, underneath lids and membrane
IH = flies
Cause a lot of irritation due to striations
What are the main features of Oxyspirura mansoni?
Hosts - birds (chickens, ducks)
Located in the corner of orbit, under membrane
Causes blindness
IH = cockroaches
Eggs deposited in eye, move to lachrymal ducts, mouth, swallowed, passed in faeces, ingestion by IH, reach infective stage, Ih consumed by DH, larvae within crop and mature into adults, move to the lachrymal ducts and matures.
What are some features of Gongylonema pulchrum?
Hosts - ruminants, pigs, etc Located in the submucosa of oesophagus and rumen Can infect humans IH = coprophagous beetles, cockroaches Covered by plates / tubercles Infection via IH
What are the general features of the superfamilt filarioidea?
Located in the blood / lymph, vessels, body cavity and CT
Indirect lifecycle –> arthropods as IH
Long and thin worms
Contain larvae or microfilariae –> no digestive tract
2 families
- Filariidae –> locate in skin / SC tissues. Cause lesions that attract IH
- Onchoceridae
What are the main features of Parafilaria multipapillosa?
Horses
Adult females located in nodules in the subcutaneous and intermuscular CT
IH = haematobia fly
The skin nodules formed by the adults open and blood that contain larvae flow onto the skin of host. the IH ingest the L3 larvae on the body of the host. The IH then transfer the larvae when they feed again.
Mainly occurs in spring/summer, not in winter –> occurs annually for 3-4 years then resolves
Stephanofilaria spp.
Found within the skin of cattle
Transmitted by Haematobia fly (Buffalo fly)
Common in cattle in QLD
Same lifecycle as Parafilaria
What are the main features of Dirofilaria immitis?
Family Onchocercidae
Heartworm
Areas of tropical and subtropical regions
Causes severe cardiopulmonary pathology and death
Chemoresistance has developed - geographical range has increased in last 10 yrs
Can infect humans but do not mature
Adults - elongated, filiform worms, females longee than males. Viviparous. Males posterior end is curled. located in the pulmonary artery and R ventricles. R atrium and caudal vena cava are infected if heavy infestations occur. Depends on size of animal’s heart
Microfilaria - found within blood, no digestive tract, nonprogressive motility, have a tapering cephalic end and a straight caudal end
What is the lifecycle of dirofilaria immitis?
Found within over 30 species - most common DH is dogs, cats can be infected but not suitable hosts
Can survive 5-7 years in dogs
IH = mosquitoes (females)
D. immitis habours intracellular bacteria called Wolbachia sp. which is an essential aspect for the survival and reproduction of heartworm. Used as a target of control (provide antibiotics) –> is involved in the pathogenesis of the disease.
Lifecycle is 6-9 months –> mosquitoes become infected with microfilariae when taking blood from infected host –> larvae mature to L3, migrate to mouthparts, when mosquito feeds next, the larvae leaves mouthpart into host via the puncture wound from IH. Travels through the skin, molts to L4, migrates to abdomen and then heart where they mature. Originally in smaller pulmonary arteries before migrating upstream to larger arteries into the heart (worms increase in size)
What is the main features of Onchocerca cervicalis?
Hosts - horses
Located in the funicular portion of the nuchal ligament
Adult worms - females very long, striated
Microfilaria - most numerous in the skin over the linea alba, face and neck
IH = midges (Culicoides spp)
Causes hair loss and reaction to the microfilaria
What species of Onchocercida are within cattle and their locations?
Oonchocerca gutturosa –> nuchal ligament
Onchocerca lienalis –> gastrosplenic ligament
Onchocerca gibsoni * –> coiled in nodues of the briskit, stifle and hip of cattle –> affects meat quality
Setaria labiatopapillosa –> located in peritoneal cavity
What speces of Onchocercida are within horses and their locations?
Onchocerca cervicalis –> funicular portion of nuchal ligament
Setaria equina –> located in peritoneal and pleural cavities, etc.
