Ruminant Parasites Flashcards
what are ruminant helminths
- nematodes: roundworms
- trematodes: fluke
- cestodes: tapeworms
what are ruminant arthropods
- insects: lice, flies etc
- arachnids: ticks and mites
what are ruminant protozoa
- coccidia: cryptosporidia
- babesia: theileria
- neospora: toxoplasma
what are endoparasites
internal parasites
occur inside the body
what are ectoparasites
externa parasites
occur outside body
what are species specific parasites in ruminants
gutworms
lungworm
lice and mange
coccidia
what are generalist parasites
liver fluke
rumen fluke
ticks
cryptosporidia
what are the parasitic phases in the life cycle
Pre-patent period
Fecundity
what are the free living stages
environmental influences
- Development, survival and transmission
- Seasonality
what are intermeditate hosts dependent on
Ecological components
Seasonality
what is a simple direct life cycle
what is the direct life cycle of GI nematodes
where do ostertagia ostertagi go
abomasum
where do teladorsagia curcumcincta go
abomasum
where do haemonchus contortus go
abomasum
where do cooperia spp go
small intestine
where do dictyocaulus viviparus go
lungs
what can extent the pre patent period
inhibition/hypobiosis
what is the life cycle of fasciola hepatica
indirect life cycle
what is the PPP of fasciola hepatica
12 weeks
what is the life cycle of dicrocoelium dendriticium
how are helminth infections acquired
by ingestion of larvae, metacercariae or invertebrae hosts while grazing
what is the seasonal dynamocs of PGE in sheep
Ewe increases egg output (PPR) onto last years supply of larvae which can be picked up the lambs as they are grazing
The larvae develop on pasture and are picked up develop inside the sheep and exponentially increase the egg output
what are infection patterns of fasciola hepatica
Intermediate hosts can impact the seasonality of infection
Snail carries infection over winter and deposits eggs onto the pasture and those infect snails in the summer
This can take awhile for snails to process through the different phases
The major infection pattern is early eggs picked up by snails and increase the # of metacercariae on the pasture —> peak in late autumn
But weather dependent
what are parasite co infections and interactions in sheep
diarrhea and fecal staining of wool from PGE can lead to fly strike (myiasis)
what are the parasite impacts on the host
Number
Location
- Pathology
Biology:
- Pathophysiology
- Biochemistry
- Endocrinology
what are the host responses of parasites
Innate defences:
- Physical barriers
- Natural chemicals
Adaptive responses:
- Acquired immunity
- Behaviour
what parasite can cause mortality
dictyocaulus viviparus
what does subclinical PGE cause
common cause of poor/uneven growth in young cattle
ostertagia ostertagi
cooperia spp
what is key to the pathogenesis of PGE
60-70% of the reduction in growth rate in sub clinically infected lambs and calves is attributed to anorexia and reduced DMI
what is the pathophysiology of liver fluke
Feeding of flukes:
- Hemorrhage/anemia
Liver damage and dysfunction:
- Diverse effects
Anorexia:
- Reduced food intake
Immunomodulation:
- Bacterial co-infection
which species can cattle develop immunity to
what are the impact of subclinical helminosis in cattle in first grazing season
growth rate
what are the impacts of subclinical helminosis in cattle in second grazing season
growth rate
carcass yield and quality
preg rate (heifers)
what are the impact of subclinical helminosis in cattle in housed cattle
feed conversion ratio
what are the impact of subclinical helminosis in dairy cattle
milk yield
calving to conception
what are the impact of subclinical helminosis in beef cattle
calf weaning weight
preg rate
what species can sheep develop immunity to
how can helminths be diagnosed
what are the tools for helminth control
what are anticoccidials
coccidiostats and coccidiocides
kill coccidia
what are anthelmintics
kill helminths
roundworms, fluke, tapeworms
what are flukicides
kill flukes
what are macrocyclic lactones (MLs)
also known as endectocides
kill internal and external parasites
ex. ivermectin, moxidectin
what are ectoparasiticides
kill external parasites
what are insecticides
kill insects
lice
flies
what are acaricides
kill arachnids
mites
ticks
what are pyrethroids
ectoparasiticides that can kill insects and arachnids
what is a POM-V
a veterinary medical product (VMP) that has been classified as a POM-V may only be supplied to the client once it has been prescribed by a veterinarian following a clinical assessment of an animal, or a group of animals, under the veterinarian care
what are POM-VPS
a veterinary medicine classified as POM_VPS may be prescribed by any registered qualified person (RQP a veterinarian, a pharmacist or an appropriately qualified suitably qualified person, SQP)
Clinical assessment of the animal(s) is not required when prescribing this category of veterinary medicine and the animal does not have to seen by prescriber. However, sufficient information about the animal and the way it is kept must be known to the prescriber and supply appropriately
what are group 1, 2, 3 anthelmintics for cattle
group 1 (white): bendimidazoles (albendazole, fenbendazole)
group 2 (yellow): levamisole
group 3 (clear): macrocyclic lactones (ivermectin, doramectin, moxidectin, eprinomectin)
and fluke wormer combos
what are anthelmintics for sheep
Group 1 (white):Benzimidazoles
- Albendazole
- Fenbendazole
- Oxfendazole
- Ricobendazole
Group 2 (yellow):
- Levamisole
Group 3 (clear): Macrocytic lactones:
- Ivermectin
- Doramectin
- Moxidectin
- Eprinomectin
Group 4 (orange):
- Monepantel
Group 5 (purple):
- Derquantel + abamectin
and fluke wormer combos
what are ruminant flukicides
what are blowflies
grazing season
lucilia sericata (green bottle)
what are tick species
ixodes ricinus
spring and autumn
what are risk factors for ectoparasites
housing
Crowding/contact (contagious)
Coats (long hair, humidity)
Cover (away from UV light
what is the generation time for lice
3-5 weeks
what is the fecudity for lice
100-330 eggs/female/month
how long can lice survive off host
3-7 days
what is the generation time of mange mites
2-3 weeks
what is the fecundity of mange mites
100-330 eggs/female/month
how long can mange mites survive off host
up to 15 days
up to 70 days (chorioptes)
what are the impacts of ectoparasites
Clinical disease
Production losses
Behavioural changes
Hide damage
how are ectoparasites diagnosed
skin scrape
visual
ELISA test (sheep scab)
what are sheep ectoparasiticides
describe what a high risk cow would be for PGE (7)
- first grazing season (<1 year old)
- <6 months at age of turnout
- <0.7 kg/day DLWG
- >200 epg fecal worm egg counts 2 months after turnout
- herbage mass low
- grazed by cattle <1 year od within last year
- bulk milk tank ostertagia ostertagi >0.8 antibodies (dairy herd)
describe what a medium risk cow would be for PGE (7)
- 1-2 years second grazing season
- age at turnout 6-8 months
- DLWG 0.7-0.8kg/day
- 50-200 epg fecal worm egg count 2 months after turnuot
- medium herbage mass and sward height
- silage/hay aftermath pasture
- grazed by cattle 1-2 years old within last year
- bulk mikl tank O. ostertagi 0.5-0.8 antibodies (dairy)
what would low risk cow be for PGE
- >2 years second grazing season
- age at turnout >8 months
- DLWG >0.8kg/day
- <50 epg fecal worm egg count 2 months after turnuot
- high herbage mass and sward height
- newly sown, ungrazed leys
- grazed by adult cattle, sheep or other species within last year
- bulk mikl tank O. ostertagi <0.5 antibodies (dairy)
what are strategic treaments at pasture
Early season anthelmintics to minimize infection build up
Summer treatment for liver fluke
what are tactical/convenience treatments at pasture
Treat in anticipation of decline in performance
Removal of helminths at key times ex. weaning
Forecast ex. nematodirosis, myiasis
what are therapeutic treatments at pasture
Treat at onset of clinical disease:
- PGE, lungworm
- Acute fasciolosis
- Sheep scab
- Fly strike
what are housing treatments for cattle
Effective removal of helminths acquired during the grazing season
- Allow good performance without impact of parasites
- Avoid risk of ostertagiosis type II
- Reduce risk of pneumonia
- Means that animals do not contaminate pastures with eggs or larvae after turnout the following year
Effective removal of cryptic populations of ectoparasites
- Reduce risk of lice or mange over winter
what is the BVA “DO” position about decision making whether or not to use anthelmintics
DO:
Ensure full grazing management programmes and the use of regular fecal egg counts to ensure treatment of only animals that need it
Target the drug used to the parasite to be treated
Emphasize the importance of not underdosing, through underestimation of body weight, maladministration of the product, or lack of calibration of dosing device
Encourage the development of farm health planning including worm strategies
Advise newly treated animals should NOT necessarily be moved immediately onto clean pasture
Explain and emphasize the importance of quarantine incoming animals and give individual guidance on their treatment
what is the BVA “DONT” position when deciding to use anthelmintics
Treat unnecessarily
Blanket treat
what does the responsble use of parasiticides entail
Risk assessment; diagnostics
Targeted treatment (TT) of groups
Targeted selective treatment (TST) of individuals
Integrated parasite management (IPM)
- Parasiticides + nutrition, husbandry, breeding
