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
Muellerius Basics & Life Cycle
o Common and difficult to control o Lungworm of goats o Requires snail intermediate host o Adults deeply embedded in parenchyma form nodules or raised areas o Usually nonpathogenic
Life Cycle • Adult in lungs -> • larvated egg coughed up and swallowed -> • hatches in intestinal tract -> • L1 in feces molts to L2, -> • Molts to L3 in snail -> • ingested by host -> • enter lymphatics -> • lung, L4 -> • airways molt to adult • PPP 4 weeks
Muellerius Diagnosis & Treatment
Diagnosis
• Baermann to identify L1
Treatment
• FBZ , Ivermectin, ABZ
• requires several treatments
Protostrongylus rufescens Basics & Life Cycle
o Domestic sheep -uncommon
o Wild sheep- very common
o Requires snail intermediate host
o Adults in small airways and alveoli (hard to find)
Life Cycle • Adult in lungs -> • larvated egg coughed up and swallowed -> • hatches in intestinal tract -> • L1 in feces molts to L2, -> • Molts to L3 in snail -> • ingested by host -> • enter lymphatics -> • lung, molt L4 -> • airways adult • PPP = 4 weeks
Protostrongylus rufescens Diagnosis & Treatment
Diagnosis
• Baermann for L1
Treatment
• FBZ , Ivermectin, ABZ
• requires several treatments
Parelaphostrongylus tenuis Basics
o Meningeal worm o Natural host is white-tailed deer o Camelids and other accidental hosts- migration in CNS can cause serious CNS damage and death o Found east of the Missouri River o Present in W & SW US
Parelaphostrongylus tenuis Diagnosis,Treatment, Prevention
Diagnosis
• Accidental hosts do not pass L1 in feces
• CSF analysis: eosinophils may be helpful
Treatment
• Prognosis is poor
• Can try Fenbendazole or IVM + doxycycline
Prevention
• Preventive treatments of ivermectin (30 days) or doramectin (45 days) when snails are abundant and where P. tenuis is endemic
Elaeophora schneideri Basics
o Filarial nematode o the “arterial worm” of wild cervids and sheep o 8-10 cm in carotid artery o Microfilaria in skin of forehead o Tabanid flies are vectors
Elaeophora schneideri Clinical Signs
Endothelial damage from the presence of adult arterial worms
• Multisystemic ischemic lesions- CNS, ears, and muzzle
• Blindness
• Sudden death
Sheep- microfilariae cause hypersensitivity
• “Sore head”- uncontrolled rubbing and itching
• Diagnose by detecting microfilariae in skin from head
Stephanofilaria stilesi
o Brisket filarial worm of cows
o Hornfly is vector
Onchocerca
o Filarial worm in connective tissue
o Intermediate hosts (vectors)- Simulium, Culicoides
o Nuchal ligament, abdominal fascia
o Microfilariae in skin
Setaria cervi
o abdominal filarid worm,
o aka necropsy worm, Surgeon’s glove worm
o Intermediate host- mosquitoes
Thelazia
o Filarid worm of eye
o Transmitted by face flys
o Treated w/ ivermectin
Fasciola hepatica Basics
o Common liver fluke
o Adult fluke can live in bile ducts for many years
o Uses snail as intermediate host
o Infective stage metacercariae encysts on aquatic plants in late spring, summer, fall
o Killed by freezing and dry conditions
o 1 cycle per year in northwest- use anthelmintics in the fall
o 2 cycles + per year gulf states
Fasciola hepatica Life Cycle
- Adult lays egg in bile ducts ->
- egg gets pooped out ->
- miracidium hatches and penetrates snail ->
- undergoes asexual amplification ->
- motile cercariae develop and leave snail ->
- metacercariae encyst on vegetation
Fasciola hepatica Acute Clinical Signs
- due to ingestion of large numbers of metacercariae over a short period of time
- Migration of immature flukes in parenchyma causes significant liver damage
- Sheep and goats are most sensitive
- Can see high mortality with heavy infections
- Can predispose animals to Clostridial infections
- Hemorrhagic, traumatic hepatitis
- Elevated serum liver enzymes
- fulminant liver failure
Fasciola hepatica Chronic Clinical Signs
- due to adult flukes in bile ducts when animals ingest more modest numbers over a longer period of time
- Often asymptomatic
- If clinical disease does develop- usually manifests in fall and winter
- Chronic poor doer & decreased weight gains
- Poor milk production & reproductive success
- Anemia, bottle jaw, and elevated liver enzymes
Fasciola hepatica Diagnosis, Treatment, Prevention
Diagnosis • History • Fecal sedimentation • ELISA serum test in Europe • Adult or larval flukes found on necropsy • Bile duct fibrosis on necropsy • fluke exhaust
Treatment
• Anthelmintics not effective against immature stages
• Clorsulon & albendazole (no use in dairy)
• Treat in fall for adults
• Maybe treat in spring
Prevention
• Fence off access to snail habitat
• Routine treatment to prevent eggs
Fascioloides magna Basics & Life Cycle
o Giant liver fluke of white tailed deer & elk
o Flukes develop into adults in cattle livers but eggs never find their way into the bile ducts
o Flukes do not fully mature in small ruminant livers
Life Cycle
• Adult lays egg in bile ducts ->
• egg gets pooped out ->
• miracidium hatches and penetrates snail ->
• undergoes asexual amplification ->
• motile cercariae develop and leave snail ->
• metacercariae encyst on vegetation
Fascioloides magna Pathology/Clinical Signs in Cows, Sheep, Goats
Cattle
• Adult flukes encapsulate in large cysts in liver parenchyma
• chronic liver disease
• No eggs in feces
Sheep & Goats
• Flukes never fully mature
• Immature flukes migrate aimlessly and cause massive liver damage
• One fluke can cause death
• Rapid onset anorexia, lethargy, depression
Fascioloides magna Diagnosis & Treatment
Diagnosis
• Elevated liver enzymes
• No eggs in feces for cows, sheeps, goats
• Fecal sedimentation for elk & deer
• Immature flukes in sheep/goat liver on necropsy
• Encapsulated adults in cow liver on necropsy
Treatment
• Difficult to treat
Dicroelium dendriticum
o “Lancet liver fluke” of ruminants
o common in NE
o Lives in bile ducts
o Small fluke produces small eggs
Paramphistomum
o Rumen fluke
o Non pathogenic
o Not common
T. solium Vs T. saginata
T. solium
• Hooks on scolex
• 5-10 lateral uterine branches
• From pork
T. saginata
• No hooks on scolex
• Highly branched uterus
• From beef
Moniezia Basics & Life Cycle
o Anoplocephalid tapeworm o over 4 meters long o Pasture mites serve as the reservoir o Young ruminants have highest infections o Concern for producers
Life Cycle • Adult in small intestine -> • proglottids and eggs in feces -> • pasture mite ingests -> • becomes cysticercoid -> • mite ingested by ruminant
Moniezia Clin Signs, Diagnosis, Treatment
Clinical Signs
• Usually non-pathogenic
• Heavy infections in young = Ds
Diagnosis
• Proglottids in manure of live animals
• Fecal float- geometric square eggs
• Adults at necropsy
Treatment
• Fenbendazole
• Albendazole
Thysanosoma Basics & Life Cycle
o Adult in bile
o tapeworm in all ruminants except cattle
Life Cyle • Proglottids in feces -> • Eggs ingested by pasture lice -> • Lice infected by cysticercoid -> • Ruminant eats lice
Taenia Saginata Life Cycle, Clin Signs, Diagnosis
o Cysticercus is only stage in cows
Life Cycle • Adult in human SI -> • egg in human feces -> • cow ingest egg off of ground -> • cysticercus in beef muscle -> • human
Clinical Signs
• Mostly non-pathogenic
• Occasional myocarditis
Diagnosis
• Meat inspection
Taenia hydatigena, ovis, multiceps
Taenia hydatigena
o Cysticerci in sheep viscera
Taenia ovis
o Cysticerci in sheep muscle
Taenia multiceps
o Coenurus in sheep brain
Echinococcus Life Cycle
- Egg from dog can infect humans and ruminants with larval hydatid cyst
- Dog consumes hydatid cyst to become infected with adult tapeworm
Eimeria Basics & Life Cycle
o Young animals most likely affected (cows < 6mo)
o Many animals are carriers
o Stress is an important factor in development or recrudescence of clinical coccidiosis
o Immunity develops and protects against disease > 1-2 years old
Life Cycle
• Ppp = 3wks
• Cow eats infective oocyst ->
• Asexual replication ->
• Sexual replication & production of oocyst ->
• Oocyst sporulates in environment to infective form
Eimeria Clinical Signs
• All result in economic losses
Acute
• often results in death
• Rapid onset diarrhea, dehydration
• Bloody Ds in cattle; not bloody in small ruminants
• CNS signs “nervous coccidiosis”- poorly understood, but tends to happen in cold regions
Subacute
• poor growth, some deaths
• Diarrhea
• Predispose to fly strike- mostly in sheep
Chronic
• constant low-level cycle in intestine
• Malabsorption, poor feed conversion
Eimeria Diagnosis Prevention Treatment
Diagnosis
• Diarrhea
• lots of oocysts in fecal flotation
• hemorrhagic enteritis on necropsy
Prevention • Amprolium in feed or water • Rigorous sanitation • Separate animals w/ Ds • Reduce stress
Treatment
• Amprolium
• Doesn’t work well
Eimeria macusaniensis Basics, Treatment, Management
o Camelid coccidiosis
o Low number of oocysts may accompany clinical disease
o Necrotizing and hemorrhagic enteritis
o Ds may precede oocyst appearance in feces
o Oocysts can be hard to float (needs high specific gravity flotation media
Treatment
• Amprolium, sulfadimethoxine
Management
• prevent overcrowding
Cryptosporidium parvum Basics, Zoonosis, Diagnosis
o Type of coccidian in young ruminants
o dairy/confinement operations as a cause of
neonatal scours
o Direct life cycle
o PPP is very short: 2-7 days
o Effective immunity generally develops following primary exposure
o No effective treatment
Zoonosis
• Ds in healthy people
• Severe clin dz & death in immunocompromised
• Immunity after infection
Diagnosis
• Fecal float
• Fecal PCR
Sarcocystis Basics, Life Cycle, Diagnosis, Control
o Protozoal infection of ruminants
o cysts develop in muscle cells
o Usually completely asymptomatic
o High level infections = ill-thrift, Weight loss, Hair loss around eyes and tail
Life Cycle
• Sexual rep and productionof oocysts in dogs, cats, humans
• Asexual rep in ruminants
Diagnosis
• Muscle biopsy
Control
• Don’t feed uncooked carcasses to dogs, cats
• Prevent access of dogs and cats to pasture and feed
Neospora caninum Basics & Life Cycle
o Toxoplasma like organism
o Dogs are definitive host
o Causes abortions in dairy cattle
Life Cycle
• Dog definitive host ->
• produces oocysts that contaminate ruminant feed/water ->
• Cattle tissue cysts ->
• Cattle can transmit transplacentally to calves ->
• Abortion OR persistent infection of calf
Neospora caninum Transmission, Diagnosis, Prevention
Transmission
• Ingestion of oocyst
• Transplacental infection
Diagnosis
• Serology shows exposure
• Must also look at histo lesions of aborted calves
Prevention
• Cull infected cows to avoid vertical transmission
• Do not feed carcass or placenta to dogs
Epidemic Vs Endemic Abortion Due to Neospora caninum
Epidemic
• Ingestion of contaminated food or water ->
• Abortion storm
Endemic
• Recrudescence of infection during pregnancy
• Mom is a persistently infected animal
Toxoplasma gondii Basics, Life Cycle, Diagnosis
o Cause of abortion in small ruminats
Life Cycle
• Cat definitive host ->
• produces oocysts that contaminate ruminant feed/water ->
• tissue cyst
Diagnosis
• Convalescent serum serology w/ four fold increase in IgG is diagnostic
• Histo of fetal tissue
Tritrichomonas foetus “Trich”; Baiscs, Life Cycle, Transmission
o Flagellated protozoan in reproductive organs of cattle
o Reduces reproductive success, Early embryonic death, Metritis in cows
Life Cycle
• Simple
• 1 trophozoite divides to 2 trophozoites
Transmission
• Bull is the source and carrier
• located in preputial folds
• Bulls > 4 years most likely to have infection
• Transfers from cow to cow by bull
• Cows typically have transient infections
• Immunity is not complete
Tritrichomonas foetus “Trich”; Pathology & Clinical Signs
• Usually mild
Cow
• Vaginitis, metritis, pyometra
• Abortion first trimester
Bull
• None
Herd • High numbers of repeat breeders • Increases in nonpregnant and late-bred cows • Decreased calving rates • Increases in fetal death rates
Tritrichomonas foetus “Trich”; Diagnosis, Prevention, Control
Diagnosis
• Definitive – find organism in bull by PCR of preputial scraping of bull
• Requires clinician performing the sampling to be trained, certified, and registered with WSDA
• Very specific protocols for collecting and submitting samples
• PCR is the standard in WA
• Highly regulated transport between states
Prevention & Control
• Rigid culling of infected bulls
• Replace with young, virgin bulls
• Replace after 90 days of sexual rest to allow cows to clear infection
• Use AI for breeding with good biosecurity protocols
• No treatments for bulls
• Vx can decrease shedding rates
Trypanosoma
o Flagellated protozoans transmitted by biting flies
o Nonpathogenic trypanosomes in cattle, sheep, and deer in the US
Giardia (in ruminants); Basics, Diagnosis, Treatment, Prevention
o Common commensal, occasional parasite
o Most commonly isolated from dairy calves 1-3 mo old
o Calves w/ chronic diarrhea that does not respond to antibiotics, electrolytes, or anti-coccidials
Diagnosis
• Fecal float w/ cysts
• Fecal smear for protozoa
Treatment
• No drug licensed for treatment in ruminats
• Fenbendazole
• Albendazole
Prevention
• Clean and dry areas thoroughly
Babesia bigemina Basics & Clinical SIgns
o Bovine babesiosis or Texas fever
o Infects erythrocytes of adult cattle
o Rhiphicephalus sp. (one host) ticks are vectors
o Eradicated from the US & REPORTABLE
Clinical Signs • High-grade fever • Anemia • Icterus • Hemoglobinuria • Cerebral babesiosis • Death can occur rapidly • Calves are not susceptible to disease
Babesia bigemina Diagnosis, Control, Treatment
Diagnosis
• Blood smear for pyriform in RBCs
Control
• Surveillance of imported cattle
Treatment
• Only used in endemic countries
• Diminazene
• Imidocarb
Theileria parva Basics, Clinical Signs, Control
o East Coast Fever
o Infects cattle lymphocytes and erythrocytes
o Africa and the Southern mediterranean
Clinical signs
• Up to 100% mortality in susceptible cattle
• Pulmonary edema and respiratory failure
• Profound lymphadenomegaly
Control
• tick control
• Live vaccine with concurrent oxytetracycline treatment
• Can treat clinical cases with oxytetracycline early
