Ch49.ParasiteControlPrograms

Question 1

Define egg reappearance periods

Answer 1

period of time from anthelmintic treatment until parasite eggs are found in the feces again

Question 2

Define prepatent period (PPP)

Answer 2

time elapsed from teh uptake of the infective stage of the parasite until it reaches patency and starts hseeding eggs to be detected in feces

Question 3

What is the PPP of equine parasites?

Answer 3

Cyathostomins: 2-3 months
Parascaris equorum: 2-3 months
Anaplasma perfoliata: 1.5 to 4 months
Strongylus vulgaris: 6-7months
Strongylus edentatus: 11-12 months

Question 4

What is the 20/80 rule in regards to parasite shedding?

Answer 4

20% of the host animals harbor approximately 80% of the parasites
** ie: about 20% of the hroses are shedding 80% of the total strongyle egg output

Question 5

define parasite refugia

Answer 5

parasite stages that escaped antihelmintic drugs and are viewd as refugees
** important factoraffecting the rate of development of anthelmintic resistance in large animal parasites

Question 6

Resistance to what anthelmintics is seen in Parascaris species?

Answer 6

ivermectin & moxidectin

Question 7

Larvae from which parasite penetrate the mucosal lining of SI/stomach and migrate the classical hepatoctracheal route, passing through lungs causing airway symptoms in young foals?

Answer 7

Parascaris

Question 8

Which parasite gives foals clinical signs of ill-thrif, weight loss, rough hair coat and pot-bellied appearance?

Answer 8

Parascaris spp

Question 9

What is the major clinical impact seen with Parascaris infections?

Answer 9

verminous small intestinal impactions
**survival beyong 1 year after colic incident associated with parascaris reporte d in 11 of 37 cases

Question 10

What is a significant risk factor for verminous small intestinal impactions associated with Parascaris in foals and why?

Answer 10

anthelmintic treatment d/t instant paralysis elicted by dewormers

** USe Benzamidazole t ype drugs

Question 11

What are the major clinical consequences of Cyathostomins (small strongyles) infections?

Answer 11

excystment– L4 penetrate their cysts & migrate short distance back to the intestinal lumen

*acute typholocolitis– larval cyathostominosis

Question 12

What is the case fatality rate reported with acute typholocolitis caused by small strongyle larval cyathostominosis?

Answer 12

50%

Question 13

What is the anthlemintic drug of choice for treatment of encysted small strongyles?

Answer 13

moxidectin (400 microg/kg PO)

**also labeled is the 5 day dose Fenbendazole (10 mg/kg PO once daily)

Question 14

Which parasites are associated with ileal impactions and ilecoceal intussceptions?

Answer 14

Tapeworms (A. perforliata)

Question 15

What anthelminitics are labeled for treatment of tapeworms?

Answer 15

praziquantel & pyrantel pamoate

Question 16

Which stage of large strongyles (Strongylins) migrate to the cranial mesenteric artery?

Answer 16

L4

Question 17

IN the cranial mesenteric artery, what do large strongyles do?

Answer 17

Molt to L5– causing a pronounced verminous endarterities with roughened intima, fibrosis of arterial walls & INC diameter of vessels

Question 18

What is the cause/pathogenesis of Strongylus vulgaris cranial mesenteric arterities?

Answer 18

Thrombi detach from the arteritis lesions (caused by L4 to L5 larvae) causing occlusion of terminal branches of vessels leading ot ischemia and infarction of intestinal segments–> colic

Question 19

Foals are usually asymptomatic to Strongylus westeri parasites, how are they exposed?

Answer 19

lactogenic transmission from the mare, or through skin

Question 20

What is the equine pin worm

Answer 20

O. equi

Question 21

What causes the perineal pruritis assocaited with O. equi infections?

Answer 21

egg patches dry up that become pruritic

Question 22

what parasite has been confused with the widely occurring culidcoides hypersensitivity?

Answer 22

Onchocerca spp– proundounced skinr eactions ventral midline and face

Question 23

Halicephalobus gingiivals larvae have a special affinity for which organs?

Answer 23

CNS
Kidneys
**multifocal, esoinphilic lesions causing C/S blindness, ataxia, CP deficits, head pressing, comba, death, etc.
**infection extremely rare