Lecture 12- rna viruses and prions

rabies virus properties

single stranded rna, enveloped, helical, “bullet shaped”, repication in cytoplasm, targets brain

what are negri bodies

intracytoplasmic inclusion bodies found in neurons, characteristic of rabies, become non infectious once dried out

transmission of rabies

infected saliva, aerosol

prodromal phase of rabies

confusion, lose fear of humans

Furious (excitation ) phase of rabies

aggressive, hyper-excitability, bite inanimate objects, roaming long distances

dump (paralytic) phase of rabies

muscle weakness, salivation, difficulty swallowing

risk factors for rabies in humans

exploring caves, camping, working in vet med, working in a lab with the virus

bite management for rabies

extensive wound washing, soap and water plus povidone iodidie kills virus, rabies shots

prevention of rabies

vaccination, keep pets away from wild animals, protect small pets from predators, remove bats from home

Arbovirus

arthropod borne virus, transmitted via flies, mosquitos, mites, bunyavirus vs flavivirus

reservoirs of arboviruses

Arthropods and vertebrates

human to human transmission of arboviruses

blood transfusion, organ transplant, sexual contact,

Bunyavirus properties

enveloped, single stranded, replication in cytoplasm

Bunyaviruses of veterinary importance

rift valley fever virus, cache valley virus, hantavirus

rift valley fever

viral zoonosis that is transmitted by mosquitos, heavy rain can cause disease outbreaks, hosts are sheep, goat and cattle, causes death and abortion storms

diagnosis of rift valley fever

histopathological lesion of liver, immunochemistry, elisa, rt-pcr of mosquito serum/tissue, use blood from viremic animals and fetal organs, liver spleen and brain

Prevention of rift valley fever

vaccinate animals, humans where ppe and use insect repellents

cache valley fever

zoonotic, transmitted to humans via mosquito bites, small ruminants are hosts

clinical signs of cache valley fever

Abortion, congenital malformation of fetuses

prevention of cache valley fever

no vaccine or treatment, vector control

diagnosis of cache valley fever

Congenital malformation of fetus, increased number of open ewes, serologic antibody testing of dams, fetal fluid antibody testing (arterial blood or peritoneal/pleural effusion

hantavirus

human host, rodents as vectors, pet rodents should be kept away from wild rodents

flavivirus properties

enveloped, spherical, vectors are ticks and mosquitos, infects birds, replication in cytoplasm, west nile fever

west nile virus clinical signs

flu like illness including fever, headache, tiredness, body aches, nausea, vomiting, neurological sins and encephalomyelitis

Diagnosis of west nile

neurologic disease, ELISA on blood samples

treatment/prevention of west nile

vaccine annually, mosquito control

west nile virus in birds

crows, blue jays and ravens are most susceptible, preventable via vaccination

Clinical signs of west nile in birds

loss of coordination, head tilt, tremors, weakness, blindness

diagnosis of west nile in birds

oral swabs in crows, heart brain and kidney

coronavirus properties

enveloped, replication in cytoplasm, helial nucleuocapsid

which coronaviruses are of veterinary importance

feline infectious peritonitis, canine corona virus, transmissible gastroenteritis in pigs, calf diarrhea, infectious bronchitis in poultry

feline infectious peritonitis

3months-2yrs more susceptible, infect wbcs, inflammation of abdomen, kidney, brain, transmitted via fecal oral

wet form of FIP

fluid accumulation in abdomen, difficulty breathing

dry form of fip

severe inflammation of eyes, brain, liver, intestine, or other organs

diagnosis of FIP

pcr, fa test of lung, intestine, liver, spleen, brain, kidney, anibody test can differentiate between coronavirus

prevention of FIP

vaccination >16 weeks, small groups of cats, avoid stress

Canine enteric corona virus

mild, self limiting diarrhea, transmitted via direct contact of dog or fecal matter, contaminated bowls

prevention of canine enteric corona virus

vaccine, isolate sick animals, keep dogs away from fecal matter, disinfect with 70% alcohol, diluted bleach, peroxide

diagnosis of canine enteric corona virus

Ifa of serum, virus isolation, pcr, fa test of intestine

canine respiratory corona virus

transmitted via dog to dog contact, aerosols, contaminated environments, more susceptible if they board, do shows

Management strategies of canine respiratory corona virus

isolation of sick/exposed dogs, sanitation, biosecurity measures

diagnosis of canine respiratory corona virus

ifa titration of serum, virus isolation, pcr

prions are

proteinaceous infectious material

Prpc

endogenous properly folded form, found on surface of nerve cells

Prpsc

Disease linked, misfolded form, can replicate with out nucleic acid, cannot be killed by heat

Transmissable spongiform encephalitis

progressive neurological disease, transmitted via contaminated feed, not contagious, no treatment or vaccine

mad cow disease

fatal neurodegenerative brain disorder, destroy infected farm animals, dont use animal products containing brain/cns as feed

scrapie

fatal disease, reportable, verify that new animals are prt of scrapie certification program and have scrapie tag ID

CWD

reportble disease, transmission via infected animals/tissue/environment, can spread people, hunters should test carcasses, wear gloves when handling