VIP past paper questions viruses

VIP past paper questions/formative quiz questions

Viruses making up the bovine respiratory disease complex/shipping fever (BRDC)

Bovine herpesvirus 1 (IBR, IPV), bovine respiratory syncytial virus, Parainfluenza 3, Bovine viral diarrhoea

Know which family they come from: Herpesviridae, Pneumoviridae, Paramyxoviridae, Flaviviridae

Most common cause of death in cats following infections from FeLV

Immunosuppression and its effects

Commonly assocaited bacteria in BRDC

Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Mycoplasma bovis, Trueperella pyogenes

True/False: Interstitial keratitis/Blue eyes in dogs may results from infection with canine adenovirus type 2

False: It’s type 1

True/False: PCR of feline coronavirus can distinguish between the low virulence enteric coronovirus and the virulent/mutant FIP-inducing coronavirus

False

Jaagsiekte in sheep in SA occurs in which two breeds primarily?

Karakul and Merino

Outside the body of the host animal, FIV can be expected to retain its infectivity for (length of time):

Only a few hours

True/False: Faecal and urine excretion of CAdV-1 is important in the spread of the virus due to its non-enveloped nature and ability to survive for substantial periods in the ideal environment

True

True/False: Retrospective diagnosis of infectious canine hepatitis by means of serology can be made if seroconversion, namely a 4 fold increase in serum Ab titre is detected in serum samples collected during the acute and convalescent phase of the disease

True

There is no evidence that parainfluenza-3 virus infection in cattle is immunosuppressive, but it does predispose lung tissue to bacterial invasion, mainly as a result of its effect on BLANK in which it is capable of replication

Alveolar macrophages

True/False: Acute canine distemper in domestic dogs is characterised by a biphasic temperature reaction

True

The use of vaccines against FeLV in cats interferes with the lab diagnosis of the natural infection when using an Ag-capture ELISA

False (ELISA is more specific)

The prevalence of solid tumours in cattle herds as a result of enzootic bovine leukosis may be as high as

10%

FIP is most likely to affect cats in what age range?

6-24 months

Porcine parvoviruses are responsible for reproductive failure in swine (embryonic and foetal death) and are important causes of the BLANK syndrome

SMEDI (stillbirth, mummification, embryonic death, infertility)

Bovine leukosis is diagnosed in the living animal by means of BLANK tests

Serology

True/False: Ab titres is a helpful lab tool to detect cats that are persistent shedders of feline coronavirus

True, but faecal RT-PCR is best

True/False: Unlike FeLV that leads to leukaemia or development of solid tumours such as lymphosarcoma, infection with FIV does not lead to the development of tumours in domestic cats

False: FIV can lead to neoplasia 25% of the time

The most common mode of FeLV transmission from one cat to another is

Direct contact with infectious saliva

Porcine foetuses killed by porcine parvovrius in utero and in which massive concentrations of virus can be detected are those with a crown-rump length of

Less than 16cm

Which of the following terms best describes the incidence of clinical FIP in the feline population

Sporadic

Which virus does not belong to the subfamily Alphaherpesvirinae

Alcephaline herpesvirus 1 and ovine gammaherpes virus 2

They belong to gamma herpes

Which 2 organ systems are most commonly targeted by herpes virus

Urogenital and respiratory systems

Match the following:
EHV-1 as a cause of abortion, EHV-2 as a cause of abortion = rare or common

EHV1 - common, EHV-2 - rare

Isolation of EHV-1/4 on equine lung cells takes

EHV-1: Within a day
EHV-2: Within 2 weeks

True/False: Oral ulceration is a common clinical sign of felid HV-1 infection

FALSE!!!!

What is the distribution of malignant catarrhal fever?

Worldwide

What is the incubation period of alcephaline HV 1?

2-4 weeks

True/False: A foetus aborted due to EHV infection in the dam can test negative for EHV

True, ALWAYS SUBMIT PLACENTA!!!

Ture/False: Immunity to EHV is lifelong

False, it is a short lived immunity, must vaccinate regularly

The live, temperature sensitive vaccine for BoHV-1 is administered via the BLANK route

Intranasal

Which 2 organ systems are affected by bovine herpesvirus 2?

Skin and Udders/Teats

True/False: Puppies greater than 2 weeks of age of infected with canid herpesvirus 1 commonly show generalized clinical signs of infection

False, they show localised infection and replication. Less than 1 week olds will show generalised infection

What is the most likely viral causes of the tongue erosions/ulcerations in a cat? 

Feline calcivirus

Which single clinical sign usually accompanies these tongue erosions/ulcers?

Hypersalivation

How can this FHV-1 and FCV be controlled by means of vaccination? Provide a detailed recommendation that includes the type of vaccine, composition of the vaccine, vaccination schedule

Vaccines against FHV-1 and FCV are used routinely in all kittens at 8-9 weeks
using modified-live or inactivated vaccines, and re-vaccination at 12 weeks are recommended

Due to maternally-derived antibody in some kittens, a third and final kitten dose should be administered at 16 weeks of age or olde

Regular booster vaccinations every 12 months (inactivated vaccines) or 36 months (attenuated vaccines) are recommended

Name the diseases in cattle caused by the following viruses:
Bovine herpesvirus 1
Bovine herpesvirus 2

Alcelaphine herpesvirus 1

Ovine herpesvirus 2

Bovine herpesvirus 1 - Infectious bovine rhinotracheitis virus, infectious pustular vulvovaginitis (IPV), balanoposthitis (IPB).

Bovine herpesvirus 2 - Bovine mammillitis virus, pseudo-lumpy skin disease, Allerton virus infection.

Alcelaphine herpesvirus 1 - Bovine malignant catarrhal fever virus, snotsiekte.

Ovine herpesvirus 2 - Sheep-associated malignant catarrhal fever.

Describe the control measures needed for an outbreak of EHV-1 epidemic on a farm

• Isolation - application of quarantine measures prior to the addition of new members to herds. Pregnant mares purchased at sales or brought from another farm should not share paddocks with the longer term resident pregnant mares and should be kept separate until after they have foaled. If the facility is not adequate for long term quarantine, newly introduced mares should be kept away for not less than 3 weeks which is about twice as long as immunologically experienced mares susceptible to infection shed virus from the nasopharynx.

• Disinfection - aborted foetuses and foetal fluids and membranes are rich sources of EHV-1 virus; if a mare aborts in a paddock or field, all of the mares in the group usually become exposed to virus in a short time. Infected foetuses, placenta, bedding and feed should be disposed by burning.

• Hygiene - personnel management; work first with non-infected animals then with infected animals.

• Submission of samples to diagnostic laboratory.

• Vaccination of pregnant mares with inactivated vaccine should be practised as an aid in control of the abortogenic disease (two month intervals starting at 5 months). Protection against abortogenic infection is required from the onset of the 6th month of gestation to term.

Which serotypes are not included in the Onderstepoort Biological Products AHSV vaccine? 

5 and 9

How should blood/organ samples be sent for AHSV isolation?

On ice, kept cool at 4C and sent over night. The virus is stable at 4C

Which blood collection tubes (EDTA, heparin, serum,

citrate, oxalate) should be used for the following tests for

African horse sickness virus?

Virus isolation, PCR, ELISA

VI: Heparin, PCR: EDTA, ELISA: Serum

Which of the following is not a characteristic of AHS:

Subcutaneous oedema

Swollen supraorbital fossae

Dyspnoea

Frothy discharge from the nostrils

Swollen legs

Cyanosis

Petechiae of the mucous membranes

And to follow, what other diseases cause that non-included characteristic

Swollen legs are characteristic of diseases such as purpura haemmorhagica and equine viral arteritis

Culicoides imicola breed in:

Moist, organically-enriched soil

The forms of AHS in order of decreasing mortality rate are:

Dunkop, Mixed, Dikkop, Fever

True/False: Neurological symptoms are a common feature of EEV

False, more common is high fever & elevated rectal temp, inappetance and red mucus memb

Rotavirus infection in cattle affects mainly the _______ system

GIT

How many serotypes of Blue tongue are there in South Africa?

21

Agree/Disagree: Pregnant ewes should be vaccinated against bluetongue virus in the first trimester of pregnancy

Disagree (Bluetongue virus vaccination can cause temporary infertility)

Agree/Disagree: Rams should be vaccinated against bluetongue virus after the mating season

Agree  🡺 Bluetongue virus vaccination can cause temporary infertility

With bluetongue virus epidemiology, cattle act as BLANK hosts and sheep act as BLANK hosts

Cattle: Maintenance/Amplifier, Sheep = Spillover

Which species is the most efficient excretors of FMDV into the environment?

Pigs

Which species is resistant to FMDV infection by the respiratory route?

Pigs

FMDV is readily inactivated by a change in

pH (reason why we let meat mature → Lactic acid makes pH lower?)

True/False: Warthogs are susceptible to FMDV

True

Ture/False: The rhino is susceptible to FMDV

False: Rhino is an odd toed ungulate (FMDV only effects even toes)

Which cells does FMDV replicate in?

Epithelial cells

How many years can cattle be carriers of FMDV?

2 years

How many years can the buffalo be a carrier of FMDV?

5 years

A ______ cup is used to obtain a scraping of pharyngeal epithelial cells (for FMDV testing)

Probang

The FMD Control Area of South Africa includes

Host differences in FMDV in sheep, pigs, cattle, buffalo

Sheep 🡪 Maintenance host (& carrier – pharyngeal tissue 4-6 months)

Pigs 🡺 Amplifier (Not a carrier)

Cattle 🡺 Indicator host (Carrier for 2 yrs)

Buffalo 🡪 Maintenance host (Carrier for up to 5 yrs)

True/False: With lumpy skin disease most animals develop skin lesions after infection

False, Only 40 - 50 % of animals developed generalized skin lesions

Agree/Disagree: Lumpy skin disease is a controlled disease in South Africa

Disagree, it is only notifiable

If extensive BLANK occurs in the upper respiratory tract, secondarily infected BLANK may be inhaled and result in BLANK.  BLANK of the trachea following healing of lesions with scar tissue formation some weeks or months after infection with lumpy skin disease virus has been described

Necrosis, necrotic tissue, pneumonia, stenosis

Skin lesions due to lumpy skin disease either resolve rapidly, become BLANK, in which case they may persist as hard lumps or BLANKS, for 12 months or longer, or desquamate as a BLANKwhich leaves a deep ulcer partly filled with granulation tissue that often suppurates

Indurated, sitfasts, sequester

True/False: Skin nodules in cattle with lumpy skin disease, appear before or during the second rise (2^nd Viraemia) in body temperature

TRUE (primary viraemia = systemic 🡪 Liver, spleen lungs)

Lumpy skin disease is caused by

Capripoxvirus

Typically, cattle develop a biphasic fever response two to four weeks after exposure to lumpy skin disease virus

True

What advice and warnings would you give to a farmer with regards to the treatment and control of orf in sheep?

• Treat severe cases symptomatically

• Local and parenteral antibiotics (not for treatment of orf itself, but the secondary bacterial complications that arise)

• Soft palatable feed

• Immunize ewes one month before parturition

• Can immunize lambs at 1 week of age

• Onderstepoort live tissue culture attenuated vaccine available

• Can make autogenous vaccine from infected material

• Scarification on inside of thigh or axilla

• Vaccinated animals can contaminate the premises

• Potential zoonosis – handle with gloves

True/False: Neuraminidase cleaves sialic acid receptors in mucin, allowing the virus to move through mucus. It also helps newly formed virions detach from infected cells

True

Major/Minor changes in surface BLANK occur through BLANK of genome segments between different influenza viruses. This is called antigenic drift/shift.

Major, glycoproteins (HA and NA), reassortment, shift

The subtype of influenza virus that is most important in horses

H3N8

True/False: The haemagglutinin (H) mediates the attachment of virus to host cells

True

Antigenic BLANK occurs when mutations in the gene sequence result in amino acid substitutions, particularly in the BLANK. It is thought to be influenced by BLANK pressure brought about, for example, by BLANK during inter-epidemic periods

Drift, HA (hemagglutinin), immunological, vaccination

The hosts that could be affected by influenza viruses

Poultry, pigs, horses, dogs (may be more, but it was a select from a list)

True/False: Pigs have a lifelong protection against re-infection by circulating PRRSV

False

For the serological diagnosis of PRRS.  Which test is the most sensitive for the detection of early antibody?

Immunoperoxidase monolayer assay (IPMA)

True/False: PRRS is nowadays not regarded as a trade sensitive disease and is therefore not a controlled disease in SA

FALSE (It is still a controlled disease even though it is not trade sensitive)

True/False: Vaccination of mares is the best way of controlling EVA in South Africa

False (Vaccination not allowed in SA Since EVA is a Controlled disease)

Carrier stallions shed EVA virus in their BLANK but not in respiratory secretions or BLANK, and the virus can/cannot be demonstrated in the buffy coat or blood

Semen, urine, cannot

True/False: Urine from mares with EVA should be considered as a potential source of contamination for at least three weeks after infection

True

True/False: The diagnosis of PMWS can be confirmed with a ELISA positive to circovirus antibody

False, demonstration of PCV2 nucleic acid and/or antigen directly associated with the lesions

True/False: The diagnosis of PMWS can be confirmed by a circovirus - positive PCR test

False, demonstration of PCV2 nucleic acid and/or antigen directly associated with the lesions

The PMWS syndrome is most commonly diagnosed in herds with BLANK incidence of the major enteric and respiratory diseases affecting pigs

Very low

True/False: The most consistent clinical signs in a pig with PMWS are wasting/unthriftiness, dyspnoea with minimal coughing and enlarged peripheral lymph nodes

True

Is African swine fever a pestivirus?

Nope, Asfivirus

True/False: African swine fever virus is the only known arthropod-borne virus with a RNA genome

False 🡺 double-stranded DNA virus. It is the only known arbovirus with a DNA genome

The classical sylvatic cycle of maintenance of African swine fever virus occurs between the following species: 

Ornithodoros tampans and warthogs (southern eastern Savannah region)

True/False: African swine fever can persist in pig populations without the involvement of wild suids or ticks

True 🡺 In sufficiently large and continuous populations of pigs, virus circulation may be maintained indefinitely through direct contact between infectious and susceptible pigs

Once African swine fever becomes established in a pig population, its further spread may occur by:

transmission through direct contact between infected and susceptible animals

indirect transmission, through for example farm workers whose hands, clothing and footwear is contaminated

feeding pigs with tissues and meat derived from pigs slaughtered in the acute stage of infection

During an outbreak of African swine fever in domestic pigs the most important means of spread is by:

Movement of infected pigs, pork and fomites 

(ASF is a highly contagious disease that is capable of very rapid spread once introduced into a domestic pig population)

True/False: Long-distance airborne transmission is important in the spread of African swine fever virus

False 🡺 only over short distances (two metres or less) in closed housing without barriers between the pigs, so is unlikely to be of any importance

Which clinical sign is most consistent in ASF

High fever indicated by huddling, anorexia and lethargy → Rectal temperatures usually attain a plateau of 41-42°C within 48 hours of the initial rise. In peracute cases death may occur during this time when, very often, other clinical signs are not evident

True/False: Pigs that recover from African swine fever become lifelong carriers of the virus

False 🡺 They may shed virus sporadically for up to 30 days post infection, but after that are not able to infect in-contact naïve pigs

Which disease preventive measures is not essential to prevent ASF

Rodent control to prevent spread by rats. Biosecurity measures should ensure that pigs do not come in contact with infected pigs, their products, or other sources of the virus including wild suids and fomites. There is no evidence that the virus is spread by rodents

Serum samples are not useful in an acute ASF outbreak because:

Most pigs die before they produce measurable antibodies:
Although serological tests are available, they are of limited value as diagnostic tools in acute, uncomplicated outbreaks, as most pigs die before producing antibodies.

True/False: An effective modified live vaccine is available for the prevention of African swine fever

False, no vaccine currently exists

Main vectors of rift valley fever:

Aedes mosquitoes (transmit it transovarially)

Which genus does Rift valley fever belong to?

Phlebovirus

True/False: Rift Valley fever is a controlled disease in South Africa

False, it is only notifiable