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Vet clinics of N. America-Food Animals > 2020, Iss1 Ruminant Parasitology > Flashcards

2020, Iss1 Ruminant Parasitology Flashcards

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1
Q

Ectoparasites of Cattle

where to haemotobia irritans (Horn flies) tend to congregate on cattle?

A

back and shoulders or underbelly during heat of the day

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2
Q

Ectoparasites of Cattle

When is treatment warranted for Haemotobia irritans (horn flies)?

A

When fly counts per animal exceed 200

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3
Q

Ectoparasites of Cattle

Besides irritation leading to production losses, what are the consequences of Horn fly infestations?

A

-mechanical vectors of bacteria causing bovine mastitis
-intermediate hosts of spirurid nematodes causing bleeding sores from stephanofilariasis

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4
Q

Ectoparasites of Cattle

Treatment options for horn flies (haemotobia irritans)

A

-insecticide resistance
-cattle-feed additives containing larvacides & insect growth regulators

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5
Q

Ectoparasites of Cattle

Where do stable flies (stomoxys calcitrans) feed on cattle?

A

Tend to feed on the legs of cattle

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6
Q

Ectoparasites of Cattle

what is the threshold for treatment of stable flies (stomoxys calcitrans)?

A

5 flies per front leg

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7
Q

Ectoparasites of Cattle

What are good preventative measures for stable fly (stomoxys calcitrans) infestations?

A

sanitation in and around cattle-raising areas prevents fly population growth locally

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8
Q

Ectoparasites of Cattle

The face fly (musca autumnalis) is feeds on what?

A

secretions form eyes and nostrils

sanguineous fluid from wounds around the face

**when feeding their mouth parts can create superficial skin lesions & ocular irritation & damage

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9
Q

Ectoparasites of Cattle

What is the threshold for treatment of face flies (Musca autumnalis)?

A

20 or more flies on the face

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10
Q

Ectoparasites of Cattle

What is the mechanical vector for Moraxella bovis?

A

face fly (Musca autumnalis)

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11
Q

Ectoparasites of Cattle

What is the intermediate host for Thelazia eye worms?

A

face fly (Musca autumnalis)

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12
Q

Ectoparasites of Cattle

Where are black flies found?

A

Flowing water
**where larvae develop

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13
Q

Ectoparasites of Cattle

What are vectors of vesicular stomatitis?

A

black flies

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14
Q

Ectoparasites of Cattle

What can occurs with swarms of black flies?

A

**significant blood loss – simuliotoxicosis
**d/t bioactive salivary factors at feeding sites assoc with persistent biting by swarms

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15
Q

Ectoparasites of Cattle

What are examples of diseases that are spread by Culicoides spp?

A

bluetongue
epizootic hemorrhagic disease
vesicular stomatitis

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16
Q

Ectoparasites of Cattle

Tsetse flies are of economic importance as ectoparasites because they spread:

A

Trypanosoma spp.
**in africa

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17
Q

Ectoparasites of Cattle

myiasis (infestation of maggots) is caused by several fly species, but primarily

A

Superfamilies muscoidea & osteroidea
caliphoridae (blow flies) and Sarchophagidae (flesh flies)– most damaging to cattle

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18
Q

Ectoparasites of Cattle

Myiases of One Health importance and are considered reportable by the WHO:

A

-New World Screwworm (Cochliomyia hominovorax) & Old World Screwworm (chrysomya bezziana)

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19
Q

Ectoparasites of Cattle

Frantic behavior by cattle to avoid female grub flies (Hypoderma bovis) attempting to lay their eggs on them is known as

A

gadding

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20
Q

Ectoparasites of Cattle

What is the treatment of Hypoderma bovis flies?

A

macrocyclic lactones
** autumn and spring
**If treated when H lineatum & H bovis grubs cluster along esopahgus & spinal column– dieing grubs can trigger respiratory distress, paralysis, & shock in treated cattle

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21
Q

Ectoparasites of Cattle

How to differentiate between biting and sucking lice:

A

sucking lice– narrow, pointed head, hematophagous

biting lice: feed on skin & hair, have a broad head

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22
Q

Ectoparasites of Cattle

In what seasons are lice burden the highest?

A

winter & early spring
–make part of treatment regimen before winter

**except for cattle tail louse– more abundant in summer

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23
Q

Ectoparasites of Cattle

Treatment for sucking lice

A

macrocyclic lactones

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24
Q

Ectoparasites of Cattle

Why are additional treatments typically required in the treatment of Lice?

A

macrocyclic lactones are inactive against lice eggs or nits

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25
Q

Ectoparasites of Cattle

Which mites are responsible for sarcoptic mange/scabies in cattle?

A

Sarcoptes scabiei var. bovis– skin burrowing mite
zoonotic

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26
Q

Ectoparasites of Cattle

What is a nonburrowing mite that causes exudative dermatitis, alopecia & intense pruritus in calves?

A

Psoroptes ovis

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27
Q

Chorioptes bovis inhabits the surface skin on which areas on cattle?

A

tail & lower legs

**tail, foot & leg mange

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28
Q

Ectoparasites of Cattle

How long can C. bovis survive off the host?

A

for up to 3 weeks

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29
Q

Ectoparasites of Cattle

When do cases of demodectic mange ovvur?

A

late winter & early spring

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30
Q

Ectoparasites of Cattle

What are the diseases listed as notifiable by the WHO for animal health caused by tick-borne pathogens that affect cattle?

A

Bovine babesiosis
anaplasmosis
theileriosis
heart water

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31
Q

Helminth vaccines in Ruminants: from development to application

There are few vaccines available against parasitic helminths of livestock currently on the market, against which parasites?

A

-Dictyocaulus vivparus in cattle
-Haemonchus contortus in sheep
-tapeworm Echinococcus granulosus in sheep

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32
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What are the effects of liver flukes on farmers?

A

-subclinical costs
-Dec milk yield & fertility
-slower growth rates
-reduced feed conversion

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33
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Environmentally when are fluke eggs killed

A

-dessicate in dry conditions
-high temperature >30C, viability periods are decreased or when temperatures <-5C
-anaerobic conditions
-severely alkaline or acidic pH (pH<4.2, >9)

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34
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What is the intermediate host for flukes?

A

Lymnaeid snails

–Galba truncatula– preferred host for F. hepatica

– miracdium penetrates ody of snail & becomes a sporocyst

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35
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What is the infective stage of flukes?

A

metacercariae

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36
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

How long can metacercariae survive on pasture?

A

Can survive up to 1 year

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37
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Can metacercariae survive in silage?

A

No, not under anaerobic conditions

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38
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

In what species are fluke eggs passed from the host?

A

Deer
sheep (if live long enough)

NOT CATTLE

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39
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What are the 2 main forms of disease seen in liver fluke infection?

A
  1. Acute fasciolosis– d/t migration of juvenile flukes through liver parenchyma
  2. Chronic fasciolosis: adult liver flukes int he bile ducts
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40
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Sheep are more suseptible to acute fasciolosis, describe the disease progression

A

liver damage & blood loss d/t migrating flukes –> anemia, proteinemia, weight loss & death

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41
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

When is chronic fasciolosis seen?

A

4 to 5 months after ingestion of smaller numbers of metacercariae
**associated with adult flukes in the bile ducts

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42
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What are the typical clinical signs of chronic fasciolosis?

A

loss of condition
anemia
submandibular edema
ascites
decreased milk yield
fibrosis
cattle– calcification of the bile ducts

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43
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Which liver fluke is contained with a pseudocyst and usually do not cause clinical signs

A

F. magna

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44
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Liver damage caused by flukes has what negative side effects?

A

Clostridium novyi bacteria to enter & result in infectious necrotic hepatitis (Black Disease)

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45
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What type of immune response predominates in infected cattle/sheep?

A

TH2/regulatory

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46
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What diagnostic methods can be used to diagnose liver flukes?

A

fecal egg count
antibody detection in milk or serum
antigen detection in feces

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47
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What is the disadvantage of fecal float for diagnosis of liver fluke infestation?

A

only patent infections can be diagnosed

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48
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

When using commercial enzyme-linked immunosorbent assays, when can antibodies be detected?

A

Detected from 2 to 4 weeks post infection

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49
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

When using the commercial enzyme linked immunosorbent assay to test for liver flukes in dairy cattle in bulk milk tank testing, what does a positive result suggest?

A

approximately 25% of the herd is seropositive

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50
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

What makes the treatment of fasciola hepatica challenging in sheep that more commonly are affected by acute fasciolosis?

A

There are no available anthelmintics against the immature stages
–> instead of timing treatment 8 weeks after peak snail season; Then treating in the spring to reduce pasture contamination

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51
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

When are dairy cattle restricted for treatment of liver flukes?

A

treatment only possible during the dry period
**doesn’t always fall at an ideal time of year

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52
Q

The Epidemiology and Control of Liver Flukes in Cattle and Sheep

Which drugs are labeled for the treatment of liver flukes in the United States?

A

Albendazole
Clorsulon
**fluke life stage treated 10 wk onward

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53
Q

Epidemiology and control of GI Nematodes of Cattle in Northern Climates

What are the four genera of trichostrongyles that are most frequently identified in cattle

A
  1. Haemonchus
  2. ostertagia
  3. Trichostrongylus
  4. Cooperia
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54
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What are parasitic diseases that are transmitted to ruminants by oocysts shed in feces of a carnivore or omnivore definitive host?

A

neosporosis
toxoplasmosis
sarcocystosis

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55
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What is the major way that neosporosis is transmitted in cattle?

A

transplacentally

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56
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What is the definitive host of neosporosis?

A

Dogs

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57
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Neosporosis is important disease in cattle because it causes

A

abortion

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58
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What is the definitive host of toxoplasmosis?

A

Cats

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59
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Toxoplasmosis causes abortion in what species?

A

sheep and goats

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60
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What are the definitive hosts of sarcocystosis?

A

dogs
cats
wild preadtors

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61
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Are there any effective preventative chemotherapeutics or vaccines available in ruminants against neosporosis, toxoplasmosis and sarcocystosis?

A

None

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62
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Which life stage of Neospora caninum disseminate infection in the intermediate host?

A

tachyzoites

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63
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What is the life stage of Neospora caninum that encysts in tissues?

A

bradyzoites

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64
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

When do a majority of Neospora related abortions occur?

A

5 to 6 months gestation
**can occur at any age 3m-end gestation

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65
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Which cows are more likely abort than not, with N caninum?

A

cows that have N caninum antibodies (seropositive) are more likely to abort than seronegative cows

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66
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What are potential neurologic signs of calves born with Neospora caninum?

A

-calves <2 months old
-underweight
-unable to rise
-born w/o C/S of dz
-Flexoral/hyperextended limb deformity
-Neuro abnorm: ataxia, dec pateller reflexes, loss of CP
+/- exophthalmia or asymmetrical appearance in eyes
-birth defects: hydrocephalus & narrowing of spinal cord

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67
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What is the definitive diagnosis of abortion related to neosporosis require?

A

histologic examination of fetus
–brain, heart, liver, placenta, body fluids or blood serum
**fetal brain most consistently affected

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68
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What is the best way to prevent vertical transmission of Neospora caninum?

A

-culling of seropositive dams and/or heifer calves from seropositive cows
-embryo transfer from seropositive cows to seronegative cows are some management strategies
**no drugs kill N caninum bradyzoites within tissue shifts

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69
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What are the infective stage of toxoplasma gondii?

A
  1. tachyzoites: individually & in groups
  2. bradyzoites: in tissue cysts
  3. sporozoites: in sporocysts w/in sporulated oocysts
70
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Which life stage of T. gondii are susceptible to anti-coccidial drugs and which ones are not?

A

Tachyzoites: metabolically active & are susceptible

bradyzoites: not metabolically active & not affected by drugs used against coccidia

71
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Where are cysts of T. gondii most prevalent in the animal?

A

-muscular and neural tissues
–brain, eye, skeletal & cardiac mm

72
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Oocysts of T. gondii are only formed in which species?

A

cats
–domestic and wild felids

73
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Sporulation of T. gondii oocysts occurs where?

A

outside of the host

74
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

How are hosts (felids) of T. gondii become infected?

A

By ingesting tissues cysts in tissues of infected animals OR sporulated occysts in food or drink OR transplacental transmission fo tachyzoites from mother to fetus

75
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

The pathogenecity of T. gondii is determined by which factors:

A
  1. innate susceptibilty of the host spp
  2. parasite virulence
  3. Stage that is acquired by the host
76
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

T. gondii infects are most severe clinically in intermediates hosts in what life stage?

A

Oocyst

77
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Toxoplasmosis is most severe in small ruminants, causing:

A

-embryonic death & resorption
-fetal death and mummification
-abortion
-stillbirth
-neonatal death

78
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Diagnosis of an acute infection with toxoplasma is indicated by:

A

4-16 fold increase in antibody titer in the second sample
**ELISA

79
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What are the 5 named species of sarcocystis that infect cattle and their definitive hosts?

A

Sarcosystis cruzi (canines)
Sarcocystis heydorni (primates)
Sarcocystis hirsuta (felines)
Sarcocystis hominis (primates)
Sarcocystis rommeli (felines)

80
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Sarcocystis: intermediate hosts become infected by ingesting what life stage?

A

sporocysts in food or water

81
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Sarcocystis the merozoites encyst in which tissues?

A

striated & cardiac mm
**occasionally CNS

82
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

What are the most pathogenic spp of sarcocystis in ruminants?

A

S Cruzi: cattle
S. capracanis: goats
S tenella Sheep

**transmitted by felids- nonpathogenic; by canids: pathogenic

83
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Clinical signs of sarcosytosis in ruminants

A

**seen when shizonts developing in blood vessels (acute infection)
– 3-4 weeks, large dose sporocysts: fever, anorexia, anemia, emaciation & hair loss (rump & tail of cattle, +/- death in some animals
-abortion in pregnant animals

84
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

Of what species of sarcocystis that infect cattle, which ones are zoonotic?

A

S. hominis
S. heydorni

85
Q

Neosporosis, Toxoplasmosis, and sarcocystosis in Ruminants: An update

How to differentiate Sarcocystis from neospora and toxoplasma in feces?

A

sporocysts or occysts of sarcocystis are shed fully sporulated in feces, vs N caninum, T. gondii and cystoisospora spp are shed unsporulated

86
Q

Sustainable approaches to parasite control in ruminant livestock

What is an alternative treatment to anthelmintics in the treatment of Haemonchus contortus?

A

copper oxide wire
secondary plant compounds (ie condensed tannins)

87
Q

Sustainable approaches to parasite control in ruminant livestock

Is copper sulfate beneficial in prevention of gastrointestinal nematodes?

A

No b/c of risk of copper toxicity in sheep & goats

88
Q

Sustainable approaches to parasite control in ruminant livestock

What is the risk of administering copper wire particles as an alternative treatment/prevention gastrointestinal nematodes?

A

Copper toxicity/liver disease
**monitoring AST as indicator of copper tox

89
Q

Sustainable approaches to parasite control in ruminant livestock

List secondary plant compounds with anthelmintic activity

A

tannins
lactones
alkaloids
saponins
terpines
glycosides
phenolic compounds

90
Q

Sustainable approaches to parasite control in ruminant livestock

What are the risks of using secondary plant compounds with anthelmintic activity against GIN?

A

-reducing feed intake
-inducing nutritional deficiencies
-triggering neurologic effects

91
Q

Sustainable approaches to parasite control in ruminant livestock

How is nematode trapping fungi used to control gastrointestinal nematodes?

A

fungi trap & destroy developing parasitic larvae in feces, by producing a variety of trapping structures

92
Q

Sustainable approaches to parasite control in ruminant livestock

Using fungal spp to control GI nematodes, requires what kind of management system?

A

Daily feeding management system
– fed for a period of 60-120 days at beginning of grazing season
–during periparturient period to reduce pasture contamination

93
Q

Sustainable approaches to parasite control in ruminant livestock

What are approaches to GI nematode reduction, that farmers that are inexpensive?

A

-optimal nutrition– feeding higher protein diets
-genetic selection of resistent/resilient livestock
-rotational grazing with multiple species (horses/cattle, with goats/sheep)

94
Q

Sustainable approaches to parasite control in ruminant livestock

Is there any benefits to feeding diatomaceous earth or herbal products (garlic, papaya, pumpkin seeds, ginger)?

A

There is no research evidence to support their use

95
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What are the 2 goals of controlling gastrointestinal nematodes?

A
  1. controlling economic losses
  2. controlling clinical disease
96
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

When is the greatest infection risk for Ostertagia in southern climates?

A

fall-Spring

97
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

In comparison to Ostertagia, which gastrointestinal nematodes are more heat tolerant?

A

C. punctata
hamonchus spp

98
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What kind of weather tends to make Gastrointestinal nematode infestations worse?

A

Rianfall

99
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

When type II ostertagiasis occurs, which cattle does it most commonly occur in?

A

older steers
replacement heifers
bulls

99
Q
A
100
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

List some management strategies that decrease larval contamination of pastures

A

-pasture rest in summer– must have rain at beginning of rest period
-alternating land use as pasture and crop/hay production
-annual or biannual pasture renovation
-cograzing with alternate, less suitable hosts– alternate calves with adult dry cows, horses, sheep & goats– not as suitable b/c H. contortus can infect cattle (esp young)

101
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What kind of breed susceptibility exists in cattle to GI nematodes?

A

Bos indicus breeds may be susceptible to Ostertagia b/c parts of the world where too hot

102
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What is the difference in susceptibility to GI nematodes in females vs males?

A

males are more susceptible than females

103
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

How are fecal egg counts used in management of livestock herds?

A

-monitoring patterns for grazing mangaement & fore determining treatment thrsholds rath than assessign infection levesl of dinividual animals

104
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

Are fecal egg counts a good indication of worm infestation?

A

No, because parasites such as Ostertagia have low fecundity

105
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

Parasite refugia can come from what two sources?

A
  1. free-living stages on pasture
  2. In animals not treated with anthelmintics
106
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

When deworming cattle, what re some considerations to minimize anthelmintic resistance?

A

-use products from 2 to 3 classes concurrently
-follow label directions for storage of products is critical
-dose based on actual weight if possible

107
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What are strategies to maintain GI nematode refugia?

A

avoid deworming all animals before turnout onto clean pastures
–esp critical with macrocyclic lactones & other long-acting products
in cow/calf operations consider only deworming cattle younger than 5 years & allow older cows to serve as refugia
-be aware of special circumstances that may alter this recommendation such as nutritional stress, treatment of liver flukes

108
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What is the time frame after deworming for GI nematodes to quarantine before turning out to pasture?

A

at least 3 days prior to pasture turnout after treatment

109
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

What is the general recommendation for maintain refugia in cow-calf operations?

A

leave adult females 4 years of age & older untreated

**to make this recommendation work, requires good nutrition and healthy animals

110
Q

Epidemiology and Control of GI Nematodes of cattle in southern climates

For fecal egg count monitoring, how many samples should be collected from each grazing gorup?

A

15 to 20 samples

111
Q

Cryptosporidium & Giardia in Ruminants

How are cryptosporidium and Giardia transmitted?

A

fecal-oral route with direct contact with host or consumption of contaminated water or food with oocysts or cysts

112
Q

Cryptosporidium & Giardia in Ruminants

What is the most common clinical symptom associated with cryptosporidium?

A

diarrhea
–inappetance, fever, or malabsorption

113
Q

Cryptosporidium & Giardia in Ruminants

What is the infective stage of cryptosporidium?

A

sporulated oocyst

114
Q

Cryptosporidium & Giardia in Ruminants

In relation to the hosts cells, where does cryptosporidium infect?

A

-intracellular, but extracytoplasmatic

115
Q

Cryptosporidium & Giardia in Ruminants

What are the factors that contribute to the transmissability of Cryptosporidium?

A
  1. simple fecal-oral transmission route with oocysts excreted fully sporulated and immediately infective to other suitable hosts
  2. oocysts can persist in harsh conditions for long periods of time
  3. oocysts are resistant to many conventional disinfectants, including chlorine
  4. ability of infected hosts to shed very large quantities of oocysts
  5. low infectious dose (10-30 oocysts)
116
Q

Cryptosporidium & Giardia in Ruminants

Cryptosporidium infection is reported in what age range of young cattle?

A

between 1 to 3 weeks of age

117
Q

Cryptosporidium & Giardia in Ruminants

What are the 4 main cryptosporidium spp responsible for infections in cattle:

A

C. parvum
C. bovis
C. ryanae
C. andersoni

118
Q

Cryptosporidium & Giardia in Ruminants

In what location in the gastrointestinal tract does cryptosporidium infect?

A

abomasum: C. andersoni
Small intestine: C bovis, C ryanae, C parvum

119
Q

Cryptosporidium & Giardia in Ruminants

Ruminants as a source of which zoonotic cryptosporidium spp?

A

C. parvum and C ubiquitum

120
Q

Cryptosporidium & Giardia in Ruminants

Cryptosporidium is concentrated in what kind of fecal float solution?

A

saturated sugar solution

121
Q

Cryptosporidium & Giardia in Ruminants

Cryptosporidium is resistant to many disinfectants, but what are adequate ways to sanitize against Crypto?

A

-cleaning stalls before introduction of new animals
-heat or chemical disinfection (hydrogen peroxide)
-Sterilization processes using steam
-UV light

122
Q

Cryptosporidium & Giardia in Ruminants

What is the infective stage of Giardia?

A

cysts

123
Q

Cryptosporidium & Giardia in Ruminants

What are factors that contribute to successful spread of giardiases?

A
  1. large numbers of cysts released into the environment by infected hosts
  2. cysts that are immediately infectious after excretion & that remain viable for extended times under right conditions (cool temps & moisture)
  3. low infectious dose
124
Q

Cryptosporidium & Giardia in Ruminants

What is the diagnostic for Giardia?

A

Microscopic examination of feces
**concentration techniques recommended & of several fecal samples (sporadically shed)

125
Q

Cryptosporidium & Giardia in Ruminants

What are management practices that can be used to decrease Giardia cysts in the environment to reduce transmission risk?

A

-regular cleaning and disinfection
-use of floor surfaces that are easy to clean in barns
-prompt removal of feces from animal housing
-use of single-cow calving areas
-adequate intake of colostrum by neonatal animals to ensure adequate transfer of passive immunity

126
Q

Ruminant Coccidiosis

What are the 3 major phases of the life cycle of Eimeria species?

A

-First two phases are internal (asexual and sexual replication)– takes 1 to 3 weeks
-next phase is environmental sporogony (sporulation)

127
Q

Ruminant Coccidiosis

What is the infective stage of coccidia?

A

sporozoites
–released by the gastric fluid contents

128
Q

Ruminant Coccidiosis

Which life stage of coccidia leaves the host cell, rupturing it?

A

merozoites

129
Q

Ruminant Coccidiosis

What are the prepatent and patent period of coccidia species?

A

Variable depending on species:
E bovis: PPP 15-23 days, PP: 5-26 days

E. zuernii: 15-22 days, PP: 2-11 days

130
Q

Ruminant Coccidiosis

Eimeria spp are resistant in the environment, what are factors that capable of affecting oocysts?

A

-direct exposure to UV light over several hours
-Extreme dryness
-high temperatures over long periods of time (about 39 C)

131
Q

Ruminant Coccidiosis

Is immunity across species of Eimeria protective?

A

**No, do not cross protect against other species

132
Q

Ruminant Coccidiosis

Acquired immunity is based on primarily on what immune response?

A

-TH1 (T helper) cellular immune response

133
Q

Ruminant Coccidiosis

Is immunity to coccidiosis complete?

A

No, immunity is protect against clinical coccidosis and doesn’t completely suppress parasite replication on reinfection

134
Q

Ruminant Coccidiosis

What species of Eimeria can cause nervous coccidiosis?

A

E. bovis & E zuernii

135
Q

Ruminant Coccidiosis

What neurologic signs can be seen with Eimeria infection?

A

eplipetiform seizures– opisthotonus & nystagmus

136
Q

Ruminant Coccidiosis

At what time of year, is nervous coccidosis most commonly seeN?

A

IN winter

137
Q

Ruminant Coccidiosis

Eimeria spp causing nervous coccidiosis pathogenesis?

A

Unknown

138
Q

What parasite is seen on fecal float?

A

Coccidia

139
Q

what parasite is seen on fecal float?

A

coccidia sporocyst/sporozoite

140
Q

Ruminant Coccidiosis

At what level on a McMasters fecal float, are coccidia oocysts considered significant?

A

500 or more

141
Q

Ruminant Coccidiosis

What are preventative measures to be taken against clinical coccidosis?

A

Herd management
-hygienic measures
-reducing stress
-timely manure removal
-deep litter usage
-non-crowded pasture
-facilites tha tallow direct natural sunlight– reduce levels of oocysts
-separation of different age groups
-pasture rotation
-appropriate passive transfer of immunity

142
Q

Ruminant Coccidiosis

What are disinfectants that are effective against coccidia?

A

bleach
cresols or chlorocresols (not available in US)

143
Q

Ruminant Coccidiosis

List drugs that are coccidiostats:

A

amprolium
decoquinate
sulfonamides

144
Q

Ruminant Coccidiosis

List drugs that are coccidiocides

A

-polyether ionophores: monesin, lasalocid, salinomycin
-symmetric triazines: toltazuril & diclazuril

145
Q

Ruminant Coccidiosis

Which medications against coccidia are intended as a single-dose oral application that is highly effective against internal stages of Eimeria that can be used for sucklign calves or lambs

A

toltrazuril

146
Q

Ruminant Coccidiosis

How long should coccidiostats be used for ?

A

at least 27 days
**ensure treated animals are under protection, b/c drugs do not kill the parasite stages immediately but inhibit their further development

147
Q

Ruminant Coccidiosis

Rather than treating coccidia infection therapeutically, what is the recommended treatment approach?

A

Metaphylactic approach

148
Q

Diagnostic methods for detecting internal parasites of livestock

What type of GI nematode egg is this?

A

Strongyle-type egg

149
Q

Diagnostic methods for detecting internal parasites of livestock

What type of GI nematode egg is this?

A

Nematodirus sp eggs

150
Q

Diagnostic methods for detecting internal parasites of livestock

What type of GI nematode egg is this?

A

Strongyloides sp eggs

151
Q

Diagnostic methods for detecting internal parasites of livestock

What type of GI nematode egg is this?

A

Trichuris sp eggs

152
Q

Diagnostic methods for detecting internal parasites of livestock

What type of GI nematode egg is this?

A

Capillarid-type egg

153
Q

Diagnostic methods for detecting internal parasites of livestock

What is the coproculture technique used for?

A

genus or species-level identification of third stage larvae (L3)

154
Q

Diagnostic methods for detecting internal parasites of livestock

What is the method most commonly used to ID lungworm larvae?

A

Baermann technique

155
Q

Diagnostic methods for detecting internal parasites of livestock

What parasite is pictured?

A

Giardia sp cysts

156
Q

Diagnostic methods for detecting internal parasites of livestock

What parasite is pictured?

A

Cryptosporidum parvum oocysts

157
Q

Biology and Epidemiology of GI nematodes in cattle

O. ostertagi has detrimental effects on the abomasum, damaging glandular tissue, specifically what cells?

A

mucus cells & pepsinogen releasing zymogen cells to be replaced by undifferentiated cells

158
Q

Biology and Epidemiology of GI nematodes in cattle

Describe type 1 O ostertagi disease

A

damage observed in fSG cattle and a result of ingested third stage large (L3) beginning 2 to 4 weeks earlier

159
Q

Biology and Epidemiology of GI nematodes in cattle

Describe type II O ostertagi disease

A

occurs in yearling housed after their first grazing season, releated to massive emergency of inhibited stages from teh mucosa

160
Q

Biology and Epidemiology of GI nematodes in small ruminants

In what time period are pastures considered safe (larvae cleared from pastures) and in what climates?

A

Temperate/cool weather: 6 months

Hot weather: 3 months

161
Q

Biology and Epidemiology of GI nematodes in small ruminants

When does hypobiosis typically occur?

A

Highest rates occur at times when conditions in the environment are least favorable for development and survival of eggs and larvae

161
Q

Biology and Epidemiology of GI nematodes in small ruminants

What dewormers within the benzimidazole drug class?

A

albendazole
fenbendazole

161
Q

Biology and Epidemiology of GI nematodes in small ruminants

albendazole is approved for the treatment of what parasite

A

sheep and goats

liver fluke, fasciola hepatica

161
Q

Biology and Epidemiology of GI nematodes in small ruminants

What is the primary mode of action of benzimdazoles

A

inhibition of microtubule formation

162
Q

Biology and Epidemiology of GI nematodes in small ruminants

Albendazole is contraindicated for use in small ruminants when?

A

firs t 30 days of gestation b/c embryotoxic effects in early pregnancy

163
Q

Biology and Epidemiology of GI nematodes in small ruminants

Is fenbendazole approved for goats or sheep?

A

Goats

164
Q

Biology and Epidemiology of GI nematodes in small ruminants

Mechanism of action of macrocyclic lactones (ivermectin)

A

interfere with chloride channel neurotransmission

165
Q

Biology and Epidemiology of GI nematodes in small ruminants

What are the two macrocyclic lactones approved for oral use in sheep?

A

moxidectin
ivermectin

166
Q

Biology and Epidemiology of GI nematodes in small ruminants

What is the mechanism of action of imidazothiazoles & tetrahydropyrimidines)?

A

nicotonic agonists– cause nematode paralysis

167
Q

Biology and Epidemiology of GI nematodes in small ruminants

What are the approved nicotinic agonist anthelminitics for use in small ruminants?

A

levamisole & morantel
**pyrantel– not approved for use in ruminants

Vet clinics of N. America-Food Animals (11 decks)

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