Superfamily Oxyuroidea and Trichinelloidea Flashcards
(28 cards)
1
Q
Superfamily Oxyuroidea characteristics
A
- “Pinworms”
- Adult worms found in the large intestine
- Highly host specific
- Common hosts include equids, ruminants, reptiles, primates, rodents, and rabbits
- NO pinworms are found in cats or dogs
- Direct life-cycle
- Have a distinguishable long, tapering tail
- Have a spherical bulb as part of the esophagus
- Human pinworm is only transmissible to other humans (or from other humans)
- –Cannot get from other animals
2
Q
Oxyuris equi morphology
A
- Found in horses
- In general, pinworms are generally small (~2-10 mm)
- In horses, females are ~15 cm, males ~ 1 cm
- Have a long, tapering tail
- Spherical bulb is characteristic of their esophagus (pumps nutrients)
3
Q
Pinworm eggs
A
- Eggs are resistant in the environment
- Elongate
- Operculated (opening that it can hatch from)
- Flattened on one side
- Thick, colorless shell
- Appears larvated
- Multicellular
- -If seen in dog or cat feces = spurious parasite (not a true parasite to that host)
4
Q
O. equi life-cycle
A
- Direct life-cycle
- Adults found in the large intestine
- Gravid females leave the rectum and cement egg masses on the perianal area
- Infective larvae develop (L3) within the eggs in 3-5 days
- -Cementing fluid dries up and aids in egg dispersal
- Fecal-oral transmission (of infective larvae)
- Larvae hatch in the small intestine and migrate to the large intestine and mature
- Prepatent period is ~5 months
5
Q
O. equi disease
A
- Mild pathology
- -Worms feeding on large intestinal mucosa
- –Catarrhal colitis or erosions
- -Worm activity of cementing eggs
- –Yellowish-gray fluid containing egg masses (cementing fluid)
- –Cementing fluid dries, cracks, and detaches from the skin in flakes (contaminates the environment)
- –Perianal irritation due to adults and egg masses
- –Rubbing anal area on objects, loss of hair at tail head (“broomtail”)
6
Q
O. equi diagnosis
A
- Scotch tape test to trap eggs and view on slide
- Rarely see eggs on fecal flotation
- Observe horses scratching rear and broken tail hairs
7
Q
Oxyuris treatment and control
A
- Fenbendazole, oxibendazole, pyrantel salts, ivermectin, moxidectin
- Several treatments may be needed
- Treat entire herd
- Reinfection is common
- Manual cleaning of the perianal area with mild detergent
- Sanitation of stable/pasture is difficult
8
Q
Superfamily Trichinelloidea
A
- Family Trichuridae (host specific - not zoonotic)
- -Genus Trichuris
- -Capillarids (group of genera)
- Family Trichinellidae (zoonotic)
- -Genus Trichinella
- Many species are of veterinary importance
9
Q
Genus Trichuris
A
=Whipworms
- Found in the large intestine (caecum)
- Trichuris vulpis (dogs and wild canids)
- Trichuris suis (pigs)
- Trichuris ovis (sheep and goats)
- Trichuris discolor (cattle)
- Trichuris tenuis (New world camelids)
- Trichuris spp. (cats)
- Trichuris trichiura (humans and primates)
10
Q
Group of genera Capillarids
A
- All are found in dogs and cats
- Cause nasal and bronchial capillariasis (occur in poultry and ruminants as well as dogs and cats)
- -Eucoleus boehmi
- -Eucoleus aerophilus
- Cause urinary capillariasis
- -Pearsonema plica
- -Pearsonema feliscati
- Cause intestinal capillariasis
- -Aonchotheca
11
Q
Genus Trichuris
A
- Adults are 3-7 cm long
- Thickened posterior body
- Long filiform anterior body
- Stichosome esophagus (cells arranged in single file)
- Adults are found in the large intestine/cecum
12
Q
Trichuris vulpis life-cycle
A
- Eggs hatch upon ingestion
- Develop into adults in intestinal epithelium (no extra-intestinal migration)
- Three month prepatent period
- -T. suis (45 days)
- -T. discolor (3 months)
- Eggs are passed in the feces (single cell stage)
- L1 develops within the egg (infective stage)
- Eggs hatch upon ingestion
13
Q
Trichuris vulpis transmission
A
- No transplacental
- No transmammary
14
Q
Trichuris vulpis disease
A
- Most infections are asymptomatic
- Heavy infections cause intermittent diarrhea = mucohaemorrhagic
- Anterior of worm embeds in the gut mucosa - typhilitis (large bowel inflammation - producing mucus to try to get rid of the worm)
- Often patient has a thin body condition
15
Q
Trichuris suis
A
- Has a shorter prepatent period (45 days)
- Young pigs can have severe disease
- Profuse mucohaemorrhagic diarrhea can occur
- Dehydration, anorexia, and growth retardation
16
Q
Trichuris diagnosis
A
- Eggs are relatively dense, therefore one of the most difficult eggs to float
- Eggs are golden to brown in color
- -Barrel-shaped
- -Bipolar plugs
- -Smooth shape
- -Tapered at both ends
- -70-89 um x 37-40 um
17
Q
Trichuris vulpis treatment and control
A
- More difficult to treat than most helminths
- -Long prepatent period
- -Several treatments may be needed (at least 3 at monthly intervals)
- -Eggs are environmentally resistant
- –Sanitation of environment is important
- –Separation of the definitive host from the contaminated environment is vital
- -Larvae and adults are resistant stages
- Preferred drugs for treatment include:
- -Fenbendazole, febantel, milbemycin oxime, and moxidectin
18
Q
Other Trichuris treatments
A
- Ruminants: ivermectin, eprinomectin, or doramectin
- Swine: dichlorvos and fenbendazole
- Cats: no approved drugs (fenbendazole or febantel may be suitable)
19
Q
Capillarid general information
A
- Unlike Trichuris, these occur in mammals as well as other vertebrates
- Similar worm morphology, but unlikely to encounter adults in general practice
20
Q
Nasal and bronchial capillariasis
A
- Occurs in dogs, cats, poultry, and ruminants
- Eucoleus boehmi
- Eucoleus aerophilus
21
Q
Eucoleus boehmi
A
- Location: frontal sinus mucosa
- Disease: nasal capillariasis
- Host: wild (red foxes) and domestic canids
- Light infections: no clinical disease
- Heavy infections: Rhinitis, serous nasal discharge, sneezing
22
Q
Eucoleus aerophilus
A
- Location: trachea, bronchi, and bronchioles
- Disease: bronchial capillariasis
- Host: canids and felids
- Light infections: no clinical disease
- Heavy infections: cough, nasal discharge, anorexia, bronchitis, occasional pneumonia
23
Q
Nasal and bronchial capillariasis diagnosis
A
- Examination of the feces, sputum, tracheal mucus, bronchoalveolar lavage fluid
- Perform either sugar centrifugal flotation or sedimentation
24
Q
Nasal and bronchial capillariasis treatment
A
- Both E. boehmi and E. aerophilus have been treated successfully with ivermectin
- E. boehmi has also been successfully treated with milbemycin oxime
- According to CAPC, routine heartworm preventatives are probably not protective against these parasites
25
Trichuris v. Eucoleus eggs
Eucoleus eggs
- Smaller (50-60um)
- Asymmetrical bipolar plugs
- Rough
- Variable cell stage
- Eucoleus boehmi
- -Pitted shell surface and multicellular embryo
- Eucoleus aerophilus
- -Reticulated net-like shell surface and single celled
Trichuris eggs
- Larger (~75 um)
- Symmetrical
- Smooth
- Single-cell stage
26
Urinary capillariasis
- Present in the renal system, esp. the bladder
- Will not encounter adults as clinicians
- Life-cycle is not well understood
- Adult worms are sewn into the mucosa of the urinary bladder
- Eggs are found in the urine
- Perform sedimentation to concentrate and find capillarid-type eggs
- Low grade cystitis and possible secondary infections
- Pearsonema plica (dogs)
- Pearsonema feliscati (cats)
27
Urinary capillariasis diagnosis
Pearsonema plica (dogs)
- 63-68 um x 24-27 um
- Barrel-shaped
- Pitted shells
- Bipolar plugs
- Colorless, unsegmented, one-cell stage
Pearsonema feliscati (cats)
- 51-65 um x 24-27 um
- Barrel-shaped
- Shell does not appear pitted
- Bipolar plugs
28
Urinary capillariasis treatment
- No approved treatments
- Ivermectin and fenbendazole have been used successfully
- -Several doses may be required to clear the infection
