Parasitology Final Master Set

Animals kept in a parasite free environment (without exposed to parasites) will develop protective immunity, and they will not suffer clinical signs on first exposure.

They will suffer severe clinical signs on first exposure

A small proportion of the ruminants in a herd shed the majority of eggs.

This is an overdispersion of eggs due to the prolific parasite shedders

What is the meaning of the arrested development period of GI nematode larvae of ruminants.

L3 and L4 can enter an “inhibited” stage, also referred to as “hypobiosis”

The wide variation in fecundity of different trichostongyle species affects the utility and reliability of diagnostic tests.

True

Chronic GI parasitism may also predispose animals to secondary infections (bacterial, viral, fungal) that would normally be able to resist.

True

Submandibular odema (bottle jaw) can occur in GI parasitism.

Clinical signs of hypoproteinaemia might include bottle jaw

Integrated parasite management plans include the following

Monitoring, treatment and other meters

Avoid deworming the entire herd at one time, and do not move the animals to clean pasture immediately after deworming.

True

Immunity to GI nematodes is acquired slowly by beef cattle.

Two grazing seasons may be required before a non-sterilizing protective immunity is attained

Biosecurity and quarantine of ruminants with GI parasites include the following

Animals with diarrhea and weakness should be separated from the rest of the herd

Lice are host-specific, obligate ectoparasites that depend on the host to complete their life cycle.

Lice are highly host-specific ectoparasites

Lice can be vectors of viruses, bacteria, fungi, and protozoa.

It is true

Bloodsucking and chewing lice are parasites of both mammals and birds.

Only chewing lice infest both mammals and birds

For cattle extent of lice infestation can be due to stressors such as high stocking density and poor feed quality.

Correct

Chewing lice feed on epidermal debris, primarily skin scales and sebaceous secretions.

True statement

All life stages of lice occur on the host, except eggs that hatch at the environment.

All life stages of lice occur on the host, including eggs

On mammalian hosts, louse eggs (nits) are glued to hairs near the skin surface.

Nits remain on hair nevertheless bathing the animal

Lice infestation creates an unthrifty appearance and lowered production in farm animals.

Often in farm animals is recorded a lower production

Ruminants do not have their own species of fleas.

Correct

Adult fleas are not host-specific.

True

Fleas are permanent ectoparasites of sheep.

Fleas visit sheep for blood feeding only

Both flea sexes feed on blood and, in case of large populations, anemia may occur.

True

Skin wounds due to flea bites may attract flies and develop traumatic myiasis.

Possible

Adult stages of Musca domestica are synanthropic, i.e. they are often associated with human dwellings and readily fly from faeces to food.

True

In facultative myiasis, the adult flies are attracted to a moist wound, skin lesion, or soiled hair coat.

Correct

Fly strike is the condition when maggots ingest dead cells, exudate, secretions, debris, and also live tissue.

Fly strike is the condition when maggots ingest dead tissue

Behaviour of sheep is a good indicator of fly strike for early diagnosis.

Indeed

Hypoderma spp. (L1) larvae secrete proteolytic enzymes that facilitate their movement and stimulate an immune response.

True

Bovine hypodermosis affects neither the productivity and welfare of animals nor any considerable losses.

It results in decreased meat and milk production

Serologic testing to detect bovine hypodermosis.

It is based on antibody detection in blood sera

Systemic insecticides containing macrocyclic lactones in pour-on and injectable formulations are effective against Hypoderma.

Correct

Systemic insecticides containing macrocyclic lactones in pour-on and injectable formulations are effective against myiasis-causing flies.

Correct

The use of ivermectin for cattle grub control is prohibited in dairy animals due to the residues present in milk for varying periods after treatment, withdrawal times for all treatments must be observed.

Correct

The use of eprinomectin for cattle grub control is not prohibited in dairy animals due to the residues present in milk for varying periods after treatment

Correct

Blood-feeding of both sexes dipteran species include stable flies and horn flies.

Correct

Female and male black flies require a blood meal to lay eggs.

Males are never blood feeders but instead feed on nectar from flowers

Attacks by large numbers of black flies can cause severe damage and high mortality in production animals.

True

Death from black fly attacks apparently results from a toxin in the saliva, which increases capillary permeability.

Correct

Biting midges are tiny gnats that inflict painful bites and suck blood of their hosts.

Correct

Culicoides spp. when in large numbers, they can make ruminants to be nervous and interrupt their feeding patterns.

True

The larval and pupal forms of stable fly develop in decaying organic matter, including grass clippings and seaweed along beaches.

Correct

Larvae of stable flies can be found in wet areas around the edges of hay stacks and silage pits.

True

Stable fly control is via sanitation, because of rapid development of larvae in straw containing faecal material.

Correct

Stable flies feed on the lower portions of cattle, around the legs and belly.

True

Adult horn flies spend their entire life on their host, and females leave only to oviposit eggs on fresh cow faeces, where larval and pupal development occurs.

Correct

Adult female horn flies oviposit eggs on fresh cow faeces, where larval and pupal development occurs.

True

Adult horn flies feeding causes pain and annoyance to cattle.

True for the adult flies

Adult horn flies cause great economic losses due to reduction in weight gain and milk production.

Correct

Adult horn flies cause great economic losses due to reduction in milk production.

True, 10-20%

The female ked gives birth to a single, fully developed larva, which is cemented to the wool.

True

Ked numbers increase during the winter and early spring.

Ked numbers increase during the winter and early spring, but they spread rapidly

What is the diet of sheep keds.

Blood

Face flies are not biting dipterans

True

Head flies are a nuisance to domestic animals and humans because they are attracted to the mouth, nose, eyes, and wounds to feed on secretions.

Correct

Musca domestica causes annoyance and pathogens transmission to ruminants.

Correct

The most pathogenic species of Theileria (eg. T. parva and T. annulata) multiply predominantly within the host WBCs, whereas less pathogenic species multiply mainly in RBCs.

Correct

There is transovarial transmission the Theileria, as occurs in Babesia.

Wrong, transovarial transmission occurs only in Babesia

Babesiosis and theileriosis are the most important tickborne diseases due to major financial losses.

Correct

Confirmation of trypanosmosis diagnosis depends on demonstrating trypanosomes in stained blood smears or wet mounts.

Correct

Wounds caused by dense clusters of adult ticks can make the host susceptible to traumatic myiasis.**

True??

Tick infestation can lead to reduced milk yield.

Tick bites can cause stress which, in combination with the anaemia, due to blood feeding, result in reduced milk yield.

The duration of the tick life cycle depends only on the tick species.

It depend on the tick species, host availability, and weather conditions

Effective biological control of ticks using plant extracts (oils) is possible.

They can be a useful alternative method for tick control

Mites causing animal mange feed on skin debris, sebaceous secretions, blood, lymph, or other material.

True

Sarcoptes scabiei is found in the skin and can survive long periods off the host.

It can only survive very short periods off the host

Ruminants become infested coming in direct contact with Sarcoptic individuals of the same species or beddings.

True

Pruritus is intense in sarcoptic mange.

True

Progressive emancipation, wool loss, skin thickening with crusts and scabs followed by reduced production are expected in long-standing cases.

True

Macrocytic lactones are fully effective against sarcoptic mange in ruminants in a single administration.

They are effective, but two administrations are recommended with 7-10 days apart to fully eliminate the mites

Psoroptes ovis os a non burrowing mite that lives on the skin surface and feed on serum and other fluid secretions from the bite wound.

True

Psoroptic mange in cattle can result in death, weight loss, decreased milk production and increased susceptibility to other diseases.

True

Psoroptes ovis transmission is primarily via direct contact of infested and susceptible hosts and also via contaminated environments and fomites.

Transmission occurs via direct contact and contaminated environments (P. ovis can survive off the host for >2 weeks under the right conditions)

Demodex bovis results in chronic inflammation, with formation of ulcers, abscesses, and fistulate with intense pruritis.

Wrong

Demodex spp. mites can be found by skin scrapings and can be easily identified microscopically due to their characteristic shape.

True

Neotrombicula autumnalis are found in clusters on the face, ears, and feet.

Only larvae are parasitic

Only Neotrombicula autumnalis larvae are ectoparasites feeding on their host blood.

Only larvae are ectoparasites

Oestrus ovis female flies are viviparous and survive up to 2 weeks, as they do not feed.

Female O. ovis flies deposit larvae on the area of the nostrils

Aquatic leeches (Limnatis nilotica) live in ponds, lakes, and streams.

Occasionally they can enter the nasal cavities or pharynx of animals by drinking water

Aquatic leeches (Limnatis nilotica) attract the veterinary interest because:

Depending on the site of attachment, they can cause severe symptoms of the upper respiratory system, including dyspnoea, cough and bleeding from the nostrils

Dictyocaulus spp. infection of ruminants is the lungworm infection of greatest economic importance.

True, they cause severe outbreaks of parasitic bronchitis in cattle of all ages

The principal source of new Dictycaulus spp. infections each year is from infected carrier animals, with overwintered larvae providing a secondary contribution in some geographic areas.

True

Clinical disease due to Dictyocaulus spp. infections in ruminants usually develops after first exposure to sufficient infective larvae.

True, the severity of disease and stimulation of an immune response is related to the number of larvae ingested

Infected animals with Dictyocaulus spp. may present bilateral nasal discharge, couching, and increased respiratory rate.

Correct

Diagnosis of Dictyocaulus spp. infection in ruminants is based on

The Baermann technique the method of choice

Antihelminthic prophylaxis is the main step for bovine lungworm Dictycaulus spp. control

Correct, with added benefit of controlling GI nematodes

If Toxoplasma gondii infection occurs in early gestation (<55 days), there is embryonic death, but if it occurs in mid-gestation, then abortion or mummified embryo is seen.

Correct

Toxoplasma gondii:

The oocysts are found only in cat (the definitive host) faeces

Toxoplasma gondii oocysts sporogony:

Sporogony occurs in 1-5 days, depending mainly on temperature

Infected with Toxoplasma gondii placentas and dead lambs should be destroyed in order to avoid being ingested by cats.

This is an important step to prevent toxoplasmosis in animals

Toxoplasma gondii oocysts are very resistant and can survive for long periods.

True, they are very resistant

Humans become infected with Toxoplasma gondii by the ingestion

Both of raw or not well cooked meat and the parasite oocysts expelled in cat faeces (e.g. in fresh salads and fruit)

Neosporosis is one of the most common causes of bovine abortion, especially in intensively farmed cows

True

Neospora caninum tachzoites represent the responsible stage for the acute phase of infection, tissue damage, and systemic dissemination.

Correct

Dogs and wild canids, such as gray wolves, coyotes, and dingoes, are definitive hosts of Neospora caninum.

Correct, all canids

Dogs have been shown to become infected with Neospora caninum by eating infected cattle, including the placentas from aborted foetuses.

Correct

The sexual cycle of Neospora caninum takes place in the dog’s intestine, while the asexual cycle occurs in the intermediate host.

Correct, plus that oocysts are expelled to the environment with dog faeces

Is Neospora caninum horizontal (postnatal) transmission possible in cattle?

Yes, it is due to ingestion of water or food contaminated with sporulated oocysts

Neospora caninum vertical transmission in cattle

Cows can become infected by consuming sporulated oocysts during pregnancy and females that are chronically infected carriers of cysts containing bradyzoites that reactivate to infective tachyzoites during pregnancy

The main risk factors for infection by Neospora caninum in cattle include

Breed, the presence of dogs and poor hygiene and biosecurity

Epidemic Neospora caninum abortion

Is a possible consequence of sudden, large-scale transmission to pregnant cattle, presumable by ingestion of a mixed ration or of water contaminated with canine faeces that contain oocysts