EPI MT 2 DECK 2 Flashcards

Question

Louping Ill Clinical signs and Pathology?

Answer 1

* 1-3 weeks incubation – biphasic fever * Depression, salivation, trembling, convulsions, tic * Ataxia (louping ill), coma, death * Frequent permanent lesions after recovery * HISTOPATH: Lymphocytic encephalitis, neuron necrosis, glia-proliferation.

Answer 2

• Mosquito transmitted disease with febrile, general signs, rash & meningio-encephalomyelitis. • Natural hosts: birds -->Detected in several bird sp. , 20-100 days viraemia. -->Differences in the level of viraemia -->ability of transmission. -->Migratory birds play a role in the long-distance spread. • Arthropod vectors: mosquitoes (ticks) • Detected in more than 60 mosquito sp. • Principle: Culex pipiens • Biological vector, vertical transmission. • • Incidental, dead-end hosts: human, horse, small mammals, amphibians, reptiles. • Non-vectorial transmission: rare, mainly human. • Seasonal Disease: Spring/ Autumn • Suspicious if CNS signs

Answer 3

* 80-90% of the infections are subclinical. * General, febrile signs. * CNS signs. * Sometimes Liver, Heart problems and other CNS problems like Guillain-Barre.

Answer 4

* Local multiplication → viraemia * Neuroinvasiveness: tumour necrosis factor-alpha, toll-like receptors * Neuron apoptosis * Abs emerge on 7-11 days post infection * Persisting infections are rare

Answer 5

* Pestivirus A = BVDV-1 * Pestivirus B = BVDV-2 * Pestivirus C = CSF * Pestivirus D = Border Disease

Answer 6

* Pestivirus very resistant to the environment, doesn’t need a vector. * Is a febrile illness of cattle with general signs, diarrhea, rarely with erosions in the mucosal surfaces of the digestive tract. Immunosuppression also. * Bovine Viral Diarrhea Virus * Susceptibility: cattle, zebu, buffalo, wild Ru, sheep (can cause border disease-like symptoms), goat, swine (subclinical). * Moderate resistance ▪ 60oC – few minutes; sensitive to disinfectants. Better compared to flavivirus other members. * In faeces, mucous survives for few weeks. Much better resistance in bodily fluids, faeces.

Answer 7

4 structural proteins, 3 enveloped with glycoprotein. There is an antigen which the AB can react, neutralizing antibodies produced against gp53 gene. One Serotype with antigenic difference between the strains so antibodies may not provide 100% protection. Lower Antibody titre produced if not the same strain that produced that antibodies.

Answer 8

Transmission between farms: • Causes cell assocaiated viraemia, BVD linked to lymphocytes-->can transmit with the same injection needle. • Persistently infected, carrier cattle (+/- without signs) • Semen of persistently infected bull. • Faeces, contaminated vehicles.

Answer 9

Transmission in the farm: • Sick or persistently infected shedders (faeces, milk, discharges, semen, aborted foetus) • Infection: PO, airborne, mating/AI • Persistently infected animals – long term (lifelong) carrier, continuous, or intermittent shedder. • Semen may contain the virus even if it is not detected in the white blood cells. • Relatively slow “invisible” spread. • In enzootic herds calves are protected by maternal Abs until the age of 3-4 months. • Signs are usually seen in 4-18 month old calves/heifers. Calves may not show clinical signs up until 6 months. • Mucosal disease is sporadic. Most severe and Rare. • Immunosuppressive virus: increased other viral & bacterial diseases, typically respiratory disease. • Ovary follicles are not infected – not transmitted with sufficient embryo transfer.

Answer 10

* PO infection – primary virus multiplication in the enteric mucosa & in the lymphatic tissue * Viraemia in 1-4 days: serum, lymphocytes → visceral organs (digestive tract, lung, spleen, lymphatic tissue, salivary gland…). * BVs endothel damage – haemorrhages. * Mucosal epithel damage – erosions. * Lymphatic tissue damage – immunosuppression

Answer 11

- Most frequently in the first pregnancy. - The virus infects the embryo/foetus. - Consequences depend on the age of the foetus & on the virulence of the virus strain. - CP strain: foetal damages, abortion, developmental disorders. First half of pregnancy= ABORTION. Second half of pregnancy foetal damages, CNS signs. - NCP strain: infertility, immunotolerance, immune response (seropositivity). And in the case on NCP: no clinical signs in cows. Day 0-40: abortion. Day 40-120: Immunotolerance. After 120 day the the immune system already developed and we can detect seropositivity in detected calves.

Answer 12

- Immunotolerant cattle, which is persistently infected with NCP strain is superinfected with a CP strain . - Or the NCP stain mutates to CP in the animal. - Severe, haemorrhagic enteritis, fibrin precipitation & erosions on the mucosal surfaces – lethal.

Answer 13

* 7-9 days incubation * In calves: Cp strain -->Fever, salivation, diarrhea, respiratory disease, Central cataract. Recovery within 1-2 weeks. * Ncp strain-->Subclinical (seroconversion), Milder immunosuppression. * Mucosal disease (rare): High fever, haemorrhagic diarrhea, Erosions on the mucosal surfaces: oral cavity, eyelids, hooves, legs , Weakness, exsiccosis, high mortality. * In cows: infertility, weaker fertilization index. Cp strain: abortions, weak, underdeveloped calves born. * Aborted foetus/infected newborn calf (cp strain): -->Brachignatia, hydrocephalus, Cerebellar hypoplasia – ataxia, ankyloses, Eyesight disorders. * In swine-->Subclinical, sometimes permanent carrier & shedder – seropositive. In pregnant sow foetal damages, delivery of weak piglets is possible.

Answer 14

• MUCOSAL DISEASE: - Sharp-edged, usually round/oval ulcers. - Gums, palate, tongue, cheek, lips - Hydroptic dystrophy, necoris (str. sp.) → erosion, ulceration -->Inflamed enteric mucosa-->Inflammation of the Peyer-patches, haemorrhagic ulceration-->Croupous or diphteroid pseudomembranes. -Haemorrhages under the serosal surfaces & on the kidney cortex. • Intrauterine infections – cerebellar hypoplasia, hydrocephalus, mictrophtalmia. • Histopath: degenerated villi, submucosal inflammatory cell infiltration.

Answer 15

* Bovine neonatal pancytopenia, idiopathic haemorrhagic diathesis of calves, Blood sweating disease, Thrombocytopenic syndrome of newborn calves. * In calves until the age of 3-4 weeks: Fever, skin haemorrhages, haematomas, blood faeces. * Low 3-5% morbidity, high mortality . * BM aplasia, thrombocytopenia, leukocytopenia. * Idiopathic: Immunopathologic process, Mycotoxicosis, other poisoning, Infectious (i.e, circovirus). * Effect of a vaccine or adjuvant: The cattle were immunized against BVDV → suspected connections with the Vaccine produced on bovine cells – anti-bovine MHC I Antibodies in the cow might damage the calf.

Answer 16

• “Foetopathogen infection of pregnant ewes characterised by retarded development & CNS damages of the lambs”. • Border disease virus (BDV) • Closely related to the BVDV. • BVDV strains can also cause disease in sheep similar to the border disease. • Rarely infects goat too. EPIDEMIOLOGY: • Persistently infected animals (sheep, cattle, wild Ru) are reservoirs. • Horizontal & vertical spread.

Answer 17

* Similar to BVD. * Manly abortions in the 1st half of the pregnancy. * Mainly foetopathy (epithelial, nervous tissue) in the second half of the pregnancy * Immuntolerance, later immune response.

Answer 18

* Weak lambs, hair-like, pigmented wool, usually on the neck & back. * Ataxia, trembling (hairy shaker). * Cranial developmental problems. * Retarded growth, high lethality. * Ewes show no signs, post-partum infections are subclinical.

EPI MT 2 DECK 2 Flashcards

(42 cards)