Final Exam Flashcards
HOT Complex Basics & Life Cycle
o Infect all ruminant species o HOT complex o Haemonchus – small ruminants mostly o Ostertagia – mosty cattle o Trichostrongylus – ALL
Life Cycle
• Short PPP
• Inhibited development (can encyst in tissue)
• Induced by environmental cues
Periparturient / Spring Rise of HOT complex
- Increase in egg output in the spring
- Especially periparturient ewes
- Mostly due to maturation of mucosal-inhibited L4 into adults
- Seeds the pasture with eggs → L3 → lambs, kids, calves
Haemonchus contortus Basics & Life Cycle
- Sheep
- Most important parasite in small ruminants
- Tropical & high humidity
- Feed on blood
- LOTS of eggs
- Rapid drug resistance
Life Cycle • Adults in abomasum produce eggs -> • Molt on pasture from egg to L3 -> • L3 ingested by host -> • L4 in mucosa -> • adult • Inhibited L4's survive winter in host • Low survival of L3's in hot/dry or cold
Haemonchus contortus Clinical Signs
Anemia
o Acute & rapid -> death
o Chronic compensated
o Chronic decompensated -> clin dz
Bottle jaw (edema)
Haemonchus contortus Pathology, DIagnosis, Treatment
Pathologic Effects
• Immunity- incomplete, develops after 6 months
• Acute disease usually in young
• Chronic disease in older animals
Diagnosis
• Strongyle eggs if fecal float
• Post mortem adults in abomasum
Treatment
• Ivermectin or fenbendazole
• Move to clean pasture
Haemonchus contortus; Control & FAMCHA / Selective Deworming
Control
• Treat ewes at parturition
• Treat lambs at weaning, move to clean pasture
• Treat all adult animals in spring to kill adult worms
• Treat all adult animals in fall to kill adults and inhibited larvae
• Tactical treatments as needed
• Increasing protein content in ewe feed in spring helps prevent spring rise
• Do FECRT to monitor drug resistance
• Vaccine available in Australia & SA
FAMCHA & Selective Deworming
• Reduce number of animals treated
• Must evaluate every animal
Ostertagia Basics & Life Cycle
- Brown stomach worm of cattle
- Most important GI nematode of cattle
- May have antithelmentic resistance
- L4s survive in gastric glands
- L3s survive on pasture
- Irrigation improves survival
Life Cycle • Adults in abomasum produce eggs -> • pasture L1, 2, 3 -> • ingested by host -> • migrate to mucosa & L4s survive in gastric glands -> • adult • PPP ~3 weeks
Ostertagiosis Type I Basics, Diagnosis, Treatment
- Adult worms cause diarrhea and reduced weight gain
- “Summer ostertagiosis”
- Most important for young pastured cattle
- Adult cattle develop modest levels of immunity
Diagnosis
o Scours in cattle less than 2 years old
o Strongyle eggs in high 100’s to low 1,000’s
Treatment
o Fenbendazole (can use in dairy)
o Ivermectin
o Moxidectin (can use in dairy)
Ostertagiosis Type II Basics, Cinical Signs, Diagnosis, Treatment
- Inhibited L4 in gastric glands cause severe abomasitis
- “Winter ostertagiosis”
- young adults & calves
Clinical signs o Emaciation o Profuse watery Ds o Chronic anemia o Protein-losing enteropathy (bottle jaw)
Diagnosis
o difficult
o Clinical signs and history
o Strongyle eggs- usually low (still L4s)
o Necropsy shows nodules on mucosa of abomasum = “Morocco leather appearance”
o Can identify tissue L4 on Mucosal scrape
o Histology of the abomasum shows larvae in gastric glands
Treatment
o Albendazole
o Ivermectin
o Moxidectin
Ostertagiosis Type II Pathogenesis
o L4 in gastric glands ->
o damage parietal cells ->
o decrease in HCl production & rise in pH ->
o no conversion of pepsinogen to pepsin ->
o severe digestive problems, diarrhea, wasting
Ostertagia Prevention & Control
- Treat spring & fall
- Treat calves w/ 400-500+ eggs
- Treat cows w/ 200 eggs
- Focus on cows <2yo (older have some immunity)
Trichostrongylus axei Basics, winter survival, & Life Cycle
- Stomach hairworm of ruminants (and horses)
- L3s survive winter on pasture
Life Cycle • Adults in abomasum produce eggs -> • pasture L1, 2, 3 -> • L3 enter host & migrate to mucosa -> • L4 -> adult • PPP ~3 weeks
Trichostrongylus axei Clinical Signs & Treatment
Clinical Signs
• Mild gastritis & reduced growth of young
Treatment
• Fenbendazole (can use in dairy)
• Ivermectin
• Moxidectin (can use in dairy)
Treating for Strongyles on Cow-Calf Operations
• Treat spring and fall
High Risk Pastures
• Heavily stocked (> 1-2 cows/acre)
• Irrigated
• Constantly grazed
High – Risk Cattle
• Weaned calves
• First and Second-season grazing cattle
Treating for Strongyles on Feedlots & Dairies
Feedlot Operations
• Weaned cattle dewormed upon arrival
• Feedlot environment uninhabitable for strongyles
Dairy
• Weaned calves require deworming
• Adults don’t need nematode treatment
• Pastured adults - unsure
Trichostrongylus sp. Basics, Clin Signs, Diagnosis
o Nematode
o Intestinal trichostrongylus are species specific
Clinical Signs • Often asymptomatic • Protracted watery Ds • Wasting / emaciation • Late summer
Diagnosis
• Strongyle egg on fecal float
• Watery Ds in late summer
• Adult worms visible on necropsy
Trichostrongylus colubriformis
- Type of trichostrongylid
- Black scour worm or bankrupt worm
- 6mm long
- small intestine of small ruminants
Cooperia
- Type of trichostrongylid
- 1cm long
- in small intestine of cows
- not usually primary cause of dz
- most prevelant parasite in cow/calf ops
- resistance to ivermectin
Nematodirus sp. Basics & Life Cycle
- Type of Trichostrongylid
- 2.5 cm
- small intestine
- Immunity often develops after 1st year of exposure
Life Cycle • L1, L2, and L3 develop in eggs -> • Eggs very cold-resistant & hatching highly dependent on weather conditions -> • Synchronized hatching of L3s -> • Outbreaks in late spring
Nematodirus sp. Clin Signs, Diagnosis, Treatment
Clinical Signs
• Often asymptomatic
• N. battus in lambs = unthrifty, severe Ds, high mortality
Diagnosis
• HUGE eggs (150-200microns)
• Heavy infection = low hundreds/gram
Treatmet
• Fenbendazole
Bunostomum Basics, Clin Signs, Diagnosis, Treatment
o Ruminat hookworm
o 2cm long
o small intestine
Clinical Signs
• Anemia
• Death in calves/lambs
Diagnosis
• Adults on necropsy
Treatment
• Ivermectin
• Fenbendazole
Strongyloides papillosus Life Cycle & Clin Signs
Life Cycle • PPP 1-2wks • Adult female in the small intestine -> • larvated egg shed on ground -> • hatches and molts L2, L3 -> • to host via ingestion or skin penetration -> • can go to *mammary gland*
Clinical Signs • If high numbers present • Ds in young • Goats more susceptible • Skin lesions • Sudden death syndrome in older calves
Capillaria
o Adults in small intestine of ruminants
o Unimportant
Oesophagostomum Basics & Life Cycle
o Nodular worm
o Strongyle
o Large intestine
Life Cycle • Host ingests L3 -> • L3 burrows into mucosa of intestine & becomes L4 -> • adult in lumen of L Int -> • strongyle egg in poop -> • molts L1 to L3 on pasture
Oesophagostomum Clin Signs & Diagnosis
Clinical Signs
• Granulomas around encysted L4 larvae
• chronic fetid diarrhea
• Ds also predispose sheep to blowfly strike
Diagnosis
• No eggs in fecal float during dz (encysted larvae)
• Strongyle egg in fecal float
• Nodules & adults in large intestine on necropsy
Chabertia ovina
o Sheep o Strongyle o Feeds on blood o Causes anemia o uncommon
Trichuris ovis Basics, Clin Signs, Treatment
o Whipworm of ruminants & camelids
o Common
o Eggs environmentally resistant
Clinical signs
• Poor growth
• bloody Ds
Treatment
• Fenbendazole
• Regular deworming every few months
Gonglyonema
o Esophageal worm
o Ruminants
Dictyocaulas Basics & Life Cycle
o Lungworm in Cattle
o Direct life cycle
o Sterilizing immunity develops and protects against disease
Life Cycle • Adult in bronchi -> • larvated egg coughed up and swallowed -> • hatches in intestinal tract -> • L1 in feces & L2, L3 on pasture -> • L3 ingested by host -> • enter lymphatics -> • lung as L4 -> • molt to adult in airways • PPP 4 weeks
Dictyocaulas Clin Signs, Treatment, Prevention
Clinical Signs • Acute lungworm disease- • mostly calves • Disease severity depends on number of worms present • Obstruct air passages • Cough • Tachypnea
Treatment
• Ivermectin, fenbendazole, or albendazole
• Move cattle off the contaminated pasture for at least several weeks, L3 do not live long
Prevention
• General nematode control program works
• Treat when suspected or necessary
• Vaccine in Britain- irradiated L3
Dictyocaulas Diagnosis
Early infections
• difficult to diagnose
• L4s are causing damage = no L1 in feces
• History, clinical signs
• Necropsy - look for larval worms in airways
Later stages of infections
• Fecal Baermann apparatus to isolate L1
