Flashcards
Cattle Parasitology
Flashcards do conjunto (42)
- 1What is Bovine Ostertagiosis?- Caused by Ostertagia ostertagi
Is a parasitic gastritis of young cattle during or following first grazing season - 2What are the clinical signs of Type I Bovine Ostertagiosis?-Bright green persistent Diarrhoea
- Weight loss in calves during first summer grazing
- Dull coats, faecal soiling
- Thirst
- High morbidity, low mortality - 3What are the clinical signs of Type II Bovine Ostertagiosis?- Weight loss
- Anaemia
- Anorexia & thirst
- Hypoalbuminaema ( submandibular oedema)
- +/- diarrhoea in yearlings during post-grazing
- Calves are infected with L3 in mid-late autumn, inhibition of early L4 in abomasal glands over winter and causes mass 'early spring emergence)
- High motality - 4What are the main species that cause Parasitic Gastroenteritis (PGE)?- Ostertagia oestertagi
- Cooperia oncophora
- Trichostrongylus sp.
- Nematodirus helvetian - 5What is the transmission cycle of GI nematodes in sheep and cattle?- Adult worms in gut of sheep
- Eggs passed onto pasture in faeces
- Young worm develops in egg in faeces
- Young worm or larva hatches
- Larvae develop to infective stage (L3)
- Infected larvae are swallowed by grazing sheep - 6What lesions might be found in the sheep or cattle to signify worm?- Might see abomasal nodules where L4 has burrowed in to the gland to develop to next stage
- Necrotic debris may be found on histological sections - 7What evidence may be present on a histological section of abomasal gland?The zonula occludens are normally tight junction with worm burden 'leak lesion', this means pepsinogen which is normally released into the abomasum will leak through the cell junctions leading to Pepsinogen in the blood
- 8What is the Epidemiology Oestertagia?Pasture larvae is relatively high and constant over January , Feb March and April. When Turnout occurs (April/May) faecal egg count will have a significant increase until mid July/August and will be off pasture by November. Pasture larvae will have a significant rise in July/August and wil
- 9How does Bovine Ostertagiosis effect Spring calving Beef herds?- Little egg production by immune adults
- Overwintered L3 die off before calves graze significant quantities ---> disease uncommon - 10How does Bovine Ostertagiosis effect Autumn/Winter calving Beef herds?- Epidemiology more like diary herds
- Type I or type II depending on grazing management - 11How is Ostertagiosis Diagnosis?- Clinical signs
- Grazing history
- Faecal egg counts (type 1 may be >1,000epg)
- Plasma pepsinogen > 3.0 i.u.
- High worm counts at post mortem - 12What Anthelmintics are Available?Group 1: Benzimidazoles. Oral, bolus for all stages
Group 2: Levamisole. Oral and injection , does not inhibit larvae Ostertagia
Group 3: Macrocyclic lactones. Orla, injection and pour-on. ALL Stages
Group 4: AADs, Monepantel. in development - 13What are the Methods of Anthelmintic Use?- Traditional - dose every 3 weeks from mid-summer
- Dose and move to clean pasture (but selects for resistance)
- Prophylactic - early and mid season treatments
- Continuous and pulse release benzimidazoles - 14What Control Options are there for Worm burdens?1. Pasture management
2. Co-graze or alternate grazing with sheep (longer term effectiveness is uncertain)
3. Use anthelmintics: no vaccines available and aim should be to stop disease - 15What Pasture Management systems are there?Set stocking: same pasture all year
Ley pasture: newly sown, cereal previous year
Aftermath: been cropped for silage or hay, larvae die out as summer progresses (L3 do not feed)
Worst pasture: - 16What disease is called by Cooperia oncophora?- Is located in the small intestine with calves normally getting immunity in first season but can Cause very sick calves with weight loss from infection,
Symptoms: loss of appetite, poor weight gain, intermittent diarrhoea - 17What causes Bovine Lungworm?Dictyocaulus viviparous
- Often very serious, young cattle in first grazing but can occur in adults
- Morbidity is >50%
- Variable mortality
- Financial cost can be in £10,000s
- Very commonly diagnosed by APHA
- VACCINE Available - 18What is the Epidemiology of Bovine Lungworm?- Temperate regions with high rainfall
- Acquired immunity strong following infection (or vaccination)
- Incidence in adult cattle has increased markedly in recent years and thought to be due to anthelmintic use
- More rapid build up than PGE
- Unpredictable - 19What is the relationship between Pilobolus fungi and Dictyocaulus?The L3 stage of Dictyocaulus will climb onto the pilobus sporangium and this will spray the L3 stage up to 3m.
- 20What is the patent phase of Dictyocaulus vivparus?26-60 days, causes parasitic bronchitis and pneumonia
Lack of growth or loss of body weight. - 21What immunity to Dictyocaulus viviparous is avialble?- There is a vaccine and acquired immunity is very effective
- However needs bosting as not lifelong immunity
- Heavy challenge can cause "re-infection syndrome" - 22How is Bovine Lungworm diagnosed?1. Post mortem examination
2. Grazing at pasture, time of year and coughing
3. Larvae in faeces - Baermann technique
4. Ab-ELISA (APHA)
NOTE: relatively few larvae are needed to cause disease - 23How is Bovine Lungworm managed in Calves?- Severity depends on : numbers L3 ingested, rate of ingestion, concurrent respiratory disease, age of animals and weather
- Single suckled calves
- Spring born calves at least risk, may have mild coughing
- Autumn born summer weaned at greatest risk - 24What are the Clinical Signs of Lung Worm in Adult Diary cattle?- Milk yield decrease
- Anorexia
- Cough
- Tachypnoea
- Hyperpnoea
- Adventitious sounds - 25How can Lung Worm in Adult Dairy Cattle be treated?- If mild then dose and move to 'clean pasture' (note may decide to move and then dose on the pasture to prevent selecting for resistance)
- Severe cases: house and give supportive care, some animals may take months to recover others will die - 26How can Bovine Lungworm be Treated?- Anthelmintics: bezimidazoles, levamisole, macrocyclic lactones
- Strategic treatment not always successful in preventing infection
- Treatment can sometimes produce fatal reaction
- Some animals may never recover fully
- Somerset farms may have ivermectin/albendazole resistant lungworm - 27What is the Lungworm Vaccination?- Is only used where lungworm is KNOWN to be present
- Is a live irradiated 3rd stage larvae given orally
- Has a 2-3 week shelf life at )2-8C)
- Requires two 25ml doses 4 weeks apart
- Should be given to calves >8 weeks of age and they should not be allowed to graze on lungworm infected pasture for 2 weeks after 2nd dose - 28What is it important to remember about the Lungworm vaccine?- The immunity is not sterile and some vaccinated animals may become carriers
- Do not mix vaccinated and non-vaccinated animals
- Buying vaccinated animals can introduce lung worm to farm - 29Which anthelmintic Bolus is best for immunity against lungworm?- "pulse" bolus, which has stages of anthelminthic which will be released but allow for some natural immunity to build up by having stages of no anthelminthic release.
- 30What is Fasciola hepatica?Liver fluke that will infect cattle, sheep, horses, rabbits, grazing animals and humans (ZOONOSIS)
The Galba (lymnaea) truncatula is the intermediate snail host - 31What is the significance of Fasciola hepatica?Increases the susceptibility to other diseases
e.g. Black disease: necrotising hepatitis due to Clostidium novyi, causes sudden death in cattle of all ages
- Salmonella Dublin
- And may compromise bovine TB diagnostic test if cattle is infected with fluke - 32What is the life-cycle of Fasciola hepatica?
- 33What are the clinical signs of Bovine Fasciolosis?- Weight loss
-Anaemia
- Sub-mandibular oedema (severe cases)
- Poor productivity - Reduction in milk yield
- Chronic disease young cattle after autumn at grass
- Immunity in older cattle (cf sheep)
- Often an infection of late autumn and winter - 34What are the signs of a Sub-Clinical Bovine Fasciolosis Infection?Dairy cattle: reduced milk yield, changes in milk quality
Youngstock: reduced feed conversion rations, poor growth, reduced carcase value, liver condemnation
- Effects on health subtle, economic impact considerable! - 35What is the Pathology of Bovine Fasciolosis?- Fibrosis and atrophy of ventral lobe of liver (due to migration of larval stages to lungs)
- Compensatory hypertrophy of dorsal lobe
- Distension, fibrosis and calcification of bile ducts "pipe stem lesions"
- Dark green-black viscid or gritty bile
- Adult fluke present - 36What is the Pathogenesis of Bovine Fasciolosis?- Chronic non-suppurative cholangiohepatitis - lymphocytes, plasma cells, eosinophils, macrophages with green-brown pigment
- Fibrosis in portal area, loss of parenchyma, biliary hyperplasia, dilation, fibrosis and calcification of bile ducts
- Acute fasciolosis (problem in sheep) - 37What is the Epidemiology of Fasciola hepatica?- Needs wet boggy areas for snails, More common in wetter areas, i.e. western half of country, Scotland and Northern Ireland
- Can occur wherever wet areas e.g. around natural springs, rivers and ditches
- Control by fencing and drainage (however due to biodiversity this is discouraged)
- Cattle grazing wet lands are particularly at risk - 38When is metacercariae on pastures possible?- Summer infection of snails (more important) causes the metacercariae on pasture August- October, will infect animals before being housed
- Winter infection of snails : metacercariae on pasture May - June - 39How is Fasciola hepatica Diagnosed with Egg Counts?- Faecal egg counts -10gr sample by precipitation and inspection 0.1 epg. Adult infection only)
- FLOTAC 1 epg
- FLUKE FINDER (differential sieving)
- Problem. Intermittent emptying of gall bladder means very variable egg counts - 40How Can Immunological Tests Diagnosed Fasciola hepatica?- Milk ELISA
- Serum ELISA
- Coproantigen ELISA (antigen for antigen of fluke)
Biochemical: liver damage
Aspartase amino transferase
Glutamate dehydrogenase - 41How can Liver Fluke be Treated?Triclabendazole: effective against all stages of liver fluke
Nitroxynil: 6 weeks of age
- Albendazole: adults
- Clorsulon + ivermectin: adult fluke
Commonly administered at housing
- No product licenced for use in lactating dairy cattle
Fasinex 240: permitted in dry period, 50 day milk withdrawal - 42What Ectoparasites are problems in Cattle?- Mange: burrowing and non-burrowing, highly pruritic, kill by ivermectins
- Warble fly: hopefully eradicated in U.K.
- Flies: majaor nuisance problem and involved in disease transmission; ear tags and sprays to control
- Ticks: especially Ixodes ricinus involved in disease transmission
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- 1 Clinical Veterinary Science FlashCards sobre Cattle Parasitology , criado por Rebecca Hitchman em 08-05-2018.
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