Final Exam Flashcards
P. tenuis zoonotic?
No
General types of parasties
cestodes- tapeworms
trematodes- flukes
nematodes- round worms
ectoparasite- fleas: ticks, mites, lice, bot flies, biting flies, midges, mosquitoes
protozoans (single- celled parasites)
- hemaprotozoans (blood parasites)
- enteric protozoans (intestinal parasites)
-tissue inhabiting protozoans (eg toxoplasmosis)
Protozoans
single celled parasites
hematoprozoans
enteric protozoans
protozoans are…
microscopic
some ectoparasites
ectoparasites
generally not life threatening especially in wildlife
can be a complicating factor when other diseases are present (ie anemia)
can be debilitating in young animals
do commonly serve as vectors for other diseases
exception to harmless ectoparasites: hair loss syndrome
disease of mule deer and BTD
exotic louse of Damalinia/ Cervicola or Bovicola sp.
Normal hosts: European and Asian cervids
hypersensitivity (allergy)- itch hair loss
may be fatal (esp to fawns in late winter) because they depend on their hair to keep them warm
Exception to harmless ectoparasites: winter tick
D. albipictus
also causes hair loss in moose (elk)
AKA Ghost Mouse
may be fatal
- exsanguination (blood loss) or hypothermia (freezing)
Exception: mange
mites. Many species cause individual animal problems
Psoroptes spp. mites cause population level issues in BHS
hair loss and extreme crusting of ears
not currently an in issue for TX Desert BHS
Deer Nose Bots
ectoparasite
Cephemnemyia fly larvae
not an accurate term, hang out in the pharyngeal pouch and when the deer dies they come out of the nose
enters deer nose, lays eggs there, deer inhales the eggs and they hatch in the pharyngeal pouch.
not considered too bothersome but the deer don’t like them
worldwide distribution
large host distribution- more common in deer
generally not pathogenic
the cause of concern for hunters re carcass quality
NOT zoonotic (also like papilloma virus- very common)
in general, ectoparasites are a big concern in wultildlife when:
when they transmit other infectious agents
Nematodes- Round Worms
P. tenuis- meningeal woem, brain worm
Elaeophora schneideri- carotide artey worm of mule deer
setaria cervi- peritoneal worms
Histomonaaaaas/ hetrakis- blackhead in turkeys
Elaeophora schneideri- carotid artery worm of mule deer
elaeophora means deer
Schenider- person who found it
a filarid worm ( like Setaria and heartworms)
adults found in carotid or maxillary artery but can occur in any large artery
spread by biting flies (horseflies- Tabindae)- carrying the microfilaria
symptoms depend on the location of the worm
16 documented species that serve as intermediate hosts
first described in sheep as “poll evil” or “sorehead”
E. schneideri
almost never a problem in mule deer (the natural host)
occasional problem in WTD
pathogenic to elk, moose, red deer, sika deer, BHS, auodad, Ibex, domestic sheep and goats
causes unilateral blindness (not common for it to be in both eyes), antler deformation, dry necrosis of ear or nose of elk, sever neurological disease
can be fatal
not ZOONOTIC
life cycle of carotid artery worm
adults in the arteries give birth to microfilaria (not eggs)
microfilaria migrate to the capillaries of the skin
biting fly ingest microfilaria with blood meal
microfilaria L1, L2, L3 in fly
L3 migrate to mouthparts of fly to be definitive host to venous blood and migrate through circulatory system to arteries and mature
Sorehead of sheep and goats
if sheep and goats are affected with Elaephora they may get the same signs as wildlife, more often they die suddenly (3-5 weeks after infection) after a short bout of neurologic signs (incordination, circling and convulsion).
death more common in young animals
those that survive often develop sorehead due to microfiliarial dermatitis 6- 10 months later
Diagnosis of E. schenideri
dead animal- disect the carotid an internal maxillary aretry and look for worms
live animals- skin biopsy
must be endemic area of mule deer ( ocasionally WTD infected)
Treatment for E. schenideri
Piperazine salts are effective
complete recovery in 2-3 weeks, damage to ear, antlers may remain
only effective before neurologic disease develops
not practical for free ranging wildlife
Parelaphostronglyus tenuis
meningeal worm
moose sickness
“extrapulmonary lungworms”
P. tenuis
Phylum Nematoda ( round worms or nematodes) have complete digestive tract (mouth though anus)
6 stages: eggs, larva (1-4), adults (both sexes)
L3 is what infects the definitive host
may have direct (no intermediate host) or indirect (intermediate host) life cycle)
Order Strongylida
most stronglyes are parasites if GIT not P tenuis!
p. Tenuis is common almost everywhere with…
WTD, usually no Disease
Debilitating on other species such as elk, moose llamas, sheep, goats, exotic ungulates
P. tenuis breakdown of name
para= near
elapho= deer
strongylus= round worm
tenuis- tenuous
P. tenuis life cycle
adults in blood vessels of brain meninges
release eggs-> heart> lungs> develop into L1
L1 coughed up, swallowed, out GIT
L1 penetrate snails > L2 >L3 (ineffective stage)
deer accidentally eats snails
L3 penetrate abomasum> nerves> spinal cord
L4> L5-> cranium (adult)
P. Tenuis
in abnormal hosts (not WTD)
no road map
cause pathology
often fatal
problems with Diagnosis of P, tenuis
there are other species of Parelaphostrongylus that are found in deer
P. andersoni is the muscle worm of WTD
P. odocoilei is found in the muscle of mule deer, BTD and woodland caribou
all have dorsal spined larvae and very difficult to separate microscopically
problems with treatment for P. tenuis
- since drugs do not cross the BBB, Ivermectin and other drugs are ineffective against adults
- Ivermectin can control the larvae for a period of time
treatment can interfere with diagnosis prior to movement of animals - movement implications
Meningeal worm concerns
As WTD expand range will P. tenuis as well?
could have major complications for moose, elk. mule deer and exotics
will drier conditions prevent westward expansion? (fewer snails and slugs)
environment plays a role! Some exotics don’t do well in wetter areas.
Histomonas/ heterakis
crater like lesions- pathopneumonic
Blackhead of Gallincacious Birds
parasite within a parasite within a worm
histomnas meleagridis- the damaging parasite ( a protozan)
heterakis gallinae- a mostly harmless cecal nematode parasite
earthworm: an optional paratenic host
Terminology review
direct lifecycle= no intermediate host needed, parasite transmitted from one definitive host to another, no intermediate host is needed
indirect life cycle- parasite requires 2 or ore different species to complete its cycle
definitive host: hosts the sexually mature stage of the parasite
intermediate host: hosts one or more of the sexually immature stage(s) of the parasite
paratenic (transport) host- not required for completion of life cycle and in which no development occurs, Usually a prey species of the definitive host
vector transmits parasite, usually an arthropod
Review
P. tenuis has an indirect life cycle
E schneideri has a indirect life cycle as well because they have intermediate hosts
definitive host for P. tenuis is WTD- accidental host
E. schenederi defnitive host is mule deer
intermediate host for P. tenuis is snail
flies are the intermediate host for E. schedderi
Bird cecum
human appendix is a rudimentary cecum
most birds have a well developed ceca at the junction of the small and large intestine (some species have two, some have one)
Lifecycle
Histomonas multiply by binary fission. H. meleagridis uses the cecal nematode, H. gallinae to protect it in the environment. Histomonads invade the nematode egg. those eggs are then often eaten by earthworms and when the bird eats the nematode egg develops in the cecum and release the histomonads
Species susceptibility to H. mileagridis
Gallinaceous birds: chukar, pheasant, quail, grouse, wild turkey, jungle fowl, guinea fowl, peafowl
Turkeys (domestic and wild) are VERY susceptible!
Domestic chickens are VERY resistant
Signs of Blackhead
7- 12 days after infection: incubation period
typically in turkeys
listlessness, reduced appetite, drooped wings, unkempt feather, sulfur yellow feces, rarely cyanosis of head (combs, waddles, etc)
Lesions
inflammation and ulceration of ceca
yellow thick- green exudate or cheesy pus in ceca
liver necrosis- maybe focal crater like entire liver, may be green or tan
Diagnosis
history and signs- presumptive
lesions- pathognomonic
direct microscopic examination of liver or cecal scraping- look for histomonads or PCR- definitive
