| A neurotropic virus that causes RABIES infecton is cuased by? | Rabies Lyssavirus |
| A non segmented bullet shaped, with negatively stranded RNA genomes? | Rabies Lyssavirus |
| the infectivity of rabies serotype 1 is destroyed by | lipid solvents |
| approximatey 180nm long and 75nm wide, its genome encodes for 5 proteins which are? | nuclear protein(n), phosphoprotien(p) glycoprotien(g) matrix protein(m) polymirase(l) |
| The lyssavirus has several serotypes which include? | Rabies virus(serotype 1),
Lagos virus (serotype 2)
Mokolu virus (serotype3)
Duvenhage virus (serotype 4)
european bat virus 1(serotype 5)
european bat virus 2 (serotype 7) |
| the lyssavirus has several serotypes. What serotype is the Rabies virus? | the rabies virus is serotype 1 |
| The rabies Genome codes for 5 protiens which are? | Nucleo protien(N)
phosphoprotien(P)
glycoprotien(G)
matrix protien(M)
polymirase(L) |
| The major structural components of the rabies virus are? | Helical ribonucleic protein (RNP) inside which the genome RNA is encased by nucleoprotien(N), and the surrounding envelope which has spike protein projections |
| The genome of the rabies virus include? | SS, anti sense and not segmented RNA which is about 12Kb. It has a leading LDR sequence of 50 nucleotides followed by the N,P,M,G, L genes |
| although, other animals have been implicated implicated, the main source of human rabies death is? | Dog. |
| other sources of human rabies in various continents include? | Europe: fox and bats
M east: wolf and dog
Asia: DOg
Africa: dog, mongoose, antelope
N. america: foxes, skunks, racoons, insectivorous Bat.
S. america: dog, vampire bats
Please note that Birds may also be susceptible to rabies. |
| the mode of transmission of rabies? | Bite of a rabid animal or contamination of scratch wound by virus infected saliva. other routes include mucous membrane of mouth, conjunctiva, anus, genitalia. man to man infection is via transplantation of cornea |
| although rare, man to man infection of rabies is vis? | transplantation of cornea. |
| the pathogenesis of rabies is highly variable with a period of 7days- several years in which the virus is localised to the site of exposure, the average time is? | 1-3 months . |
| the factors that influence pathogenesis include? | 1) variant, 2) dose of inoculum, 3) wound severity,4) individual host factors: age and immune defence, 5) length of neural path to brain: face vs leg. |
| what happens after inoculation of the rabies virus? | virus enters the PNS directry and migrate to the brain or replicate in the muscle tissue.
spread to various organs via the neuromuscular junction.
spread to the CNS via endoneurome of shwann cells.
although wide spread CNS involvement, few neurons show structural abnormalities |
| in the replicatio process of the rabies varius, first stage is the absorption stage. what happens here? | ABSORPTION: Fusion of viral envelope to host membrane |
| in the Penetration phase? | PENETRATION: CYTOPLASM ENTRY via pinocytosis |
| during UNCOATING..? | UNCOATING: viral membrane fuse to endosomal membranes and lease viral RNA into cytoplams. |
| mRNA transcription occurs after and before? | before TRANSCRIPTION, after UNCOATING. mRNA transcription; by encoded polymerase (L gene): to leader RNS and 5 capped and polyadenylated mRNA which are translated to protiens. |
| what occurs during TRANLATION? | synthesis of N,P,M,G, and L protiens. occurs on free ribosomes in cytoplasm. Note: although G protein is initiated on free ribosomes, completion of sunthensis and glycosylation occurs in E.R and golgi apparatus. |
| although G protein is initiated on free ribosomes, completion of synthesis and glycosylation occurs ? in E.R and golgi apparatus. | G protein is initiated on free ribosomes, completion of synthensis and glycosylation occurs in E.R and golgi apparatus. |
| the stage of REPLICATION occurs before and after? during which the following occurs? | Replication occurs before ASSEMBLY and after TRANSLATION. REPLICATION: regulation based on leader RNA to N PROTEIN ratio. virus switches from transcription to replication.
once switches occurs, RNA transcription becomes non stop. stop codon ignored. viral protein enters at 3' prime end.
sythensis of full lenght copies positive strands. pos strands is template for negative strand genome. |
| during ASSEMBLY...? | NPL encapsulates neg strand RNA to form RNP core. M protein forms a capsule around RNP. M-RNP complex move to area of plasma membrane containing glycoprotein inserts. M protein initiates coiling. |
| during BUDDING..? | M-RNP complex binds to glycoprotien and buds from plasma membrane. |
| in the CNS, budding occurs from the plasma membrane. in the Salivary glands, budding occurs? | from cell membrane to the acinar lumen; to maximize infection of a new host. |
| the clinical features of the rabies infection has the non specific prodrome phase which includes; fever, maliase, anorexia, nausea and vomit, headaches, sore throat and myalgia, irritability and abnormal sensation around wound. the prodrom is followed by two patters which are? | 1) Furious form: hyper excitability, spasms and hydrophobia
2) dumb form: ascending paralysis> longer survival rate |
| the prodrome clinical features of rabies is followed by two patters, furious and dumb form. which of these has the longer survival period? | dumb patter. |
| once clinical signs appear, disease is nearly fatal. treatment is supportive. the pathology of rabies infection is defined by? | encephalitis and myelitis. |
| complications of rabies infection affect many systems. they include? | cardiovascular : dysarrhythmias
CNS: increased intracranial pressure (contributes to the decreased level of
consciousness and to focal convulsions), disturbances of thermoregulation, diabetes insipidus, autonomic dysfunction and convulsions.Cerebral dysfunction, abnormal behaviour, hallucinations and insomnia.
respiratory system: respiratory complications eventually develop and
contribute to death. Respiratory
disturbances occur in all cases. |
| which systemic complication occur in all cases of rabies infection? | respiratory complication occur in all cases. |
| what are the differential diagnosis of rabies? | The differential diagnosis of rabies includes
• Tetanus
• Poliomyelitis
•Guillain-Barre syndrome
• Viral encephalitis
• Poisonings and drugs |
| the lab diagnosis for rabies include? | The diagnosis of animal and human rabies
can be made by:
(1) Electron microscopy
(2) Direct fluorescent antibody test (dFA)
(3) Virus antigen detection test
(4) Amplification methods (PCR)
(5) Virus cultivation
(6) Serology tests
(7) Histopathology
(8) Immunohistochemistry |
| This test is based on the observation if
infected animals have the rabies virus
(antigen) present in their tissues. | direct fluorescent antibody test. |
| The ideal tissue to test for the antigen is the?
The most important part of a dFA test is? | The ideal tissue to test for the antigen is the
brain.
The most important part of a dFA test is
fluorescent labelled anti-rabies antibody. |
| The rabies antibody used for the dFA test is
primarily directed against ? | The rabies antibody used for the dFA test is
primarily directed against the
nucleoprotein (Ag) of the virus |
| The virus replicates in the cytoplasm of
cells, and infected cells may contain ? | The virus replicates in the cytoplasm of
cells, and infected cells may contain large
round or oval inclusions containing
collections of the nucleoproteins or smaller
collection of Ag that appear as dust like
fluorescent particles if stained by dFA
methods. |
| The most definitive means of diagnosis is
by virus cultivation from infected tissue. Tissue culture lines include ? | Tissue culture lines such as WI-38, BHK-21,
or CER can be used. |
| The more commonly used method for virus
isolation is by the inoculation of? | by the inoculation of saliva,
salivary gland tissue and brain tissue intra
cerebrally into infant mice.The mice should develop paralysis and
death within 28 days. Upon death, the brains are examined for
the presence of the virus by immunofluorescence. |
| Histologic examination of biopsy or autopsy
tissues is occasionally useful in diagnosing
unsuspected cases of rabies that have not been
tested by routine methods. staining is with? they show what? | The tissues materials are stained with
haematoxylin and eosin stains looking for the
presence of mononuclear infiltrations,
perivascular cuffing of lymphocytes or PMNs,
lymphocytic foci, Babes nodules consisting of
glial cells and Negri bodies. |
| •Negri bodies are pathognomonic of rabies.
Credited to Dr. Adelphi Negri in 1903
•However, they are only present in % of cases? | 71% of cases |
| The picture shows a Negri body in infected neuron (arrow).. In how many cases of the infection is this seen? | 71% of cases |
| This technique can confirm direct
fluorescent antibody results and can detect
rabies in saliva and skin biopsy samples? | PCR. Rabies RNA can be copied into a DNA
molecule using reverse transcriptase
enzyme. The DNA copy then is amplified using a
polymerase chain reaction (PCR) method. |
| Once rabies is established, there is nothing much
that could be done except intensive supportive
care. in post exposure prophylaxis? | In cases of animal bites, the animal (dogs,
cats) in a rabies endemic area, should
beheld for 10 days for observation.
•If signs develop, they should be killed and
their tissue examined in the laboratory.
Wild animals are not observed but if
captured, the animal should be killed and
examined. |
| The essential components of post exposure
prophylaxis are the local treatment of
wounds and active and passive immunization. the advised wound treatment is? | surgical debridement
should be carried out. The wound should not
be sutured up. |
| In rabies wound treatment, the wound should NOT
be sutured up. True of false? | True. the wound should NOT be sutured. |
| passive rabies immunisation include? | Passive immunization: Human rabies Ig around the area
of the wound; to be supplemented with an i.m. dose to
confer short term protection.
Equine rabies immunoglobulin (ERIG) is available in
many countries and is considerably cheaper than HRIG. |
| Equine rabies immunoglobulin (ERIG) is NOT available in
many countries and is considerably MORE EXPENSIVE than HRIG. True or false? | FALSE. Equine rabies immunoglobulin (ERIG) IS available in
many countries and is considerably CHEAPTER than HRIG. |
| IN ACTIVE IMMUNIZATION OF RABIES? | Active immunization - the
human diploid cell vaccine is
the best preparation available. |
| WHAT is the procedure of rabies vaccine admistration? | The vaccine is usually
administered into the deltoid
region, and 5 doses are usually
given. |
| what is the advice regarding those who at higher risk of rabies exposure? | Persons who are regularly at high risk of exposure,
such as vets, laboratory workers, animal handlers and
wildlife officers should be considered for preexposure prophylaxis by active immunization with
the cell culture vaccine. Immunization normally consists of 3 doses of
vaccine. Antibody can be demonstrated in the sera of
virtually 100% of those vaccinated if the diploid cell
culture vaccine is used. |
| Immunization normally consists of 3 doses of
vaccine. Antibody can be demonstrated in the sera of
virtually 100% of those vaccinated if the diploid cell
culture vaccine is used. true or false? | true. |
| for persons at continued risk of rabies exposure administration of booster ? | Booster doses should be offered to persons at
continuing risk every one to three years. |
| Booster doses should be offered to persons at
continuing risk every TEN year. true or false? | false. Booster doses should be offered to persons at
continuing risk every one to three years. |
| Local treatment of wounds should always be
carried out in exposed persons who have been
vaccinated previously. true or false? | true. Local treatment of wounds should always be
carried out in exposed persons who have been
vaccinated previously. |
| when is passive immunisation contraindicated in rabies? | The WHO expert committee considers that
local infiltration with antiserum is optional and
systemic passive immunization
contraindicated. |
| The WHO expert committee considers that
local infiltration with antiserum is optional and
systemic passive immunization
IS INDICATED. true or false? | false.T he WHO expert committee considers that
local infiltration with antiserum is optional and
systemic passive immunization
CONTRAINDICATED. |
| Several types of live attenuated vaccines are
available for use in animals, but they are
considered to be unsuitable for humans. The vaccines which are available for humans are present as? | Inactivated whole virus vaccines? |
| Several types of live attenuated vaccines are
available for use in animals and they are
considered to be SUITABLE for humans. IS THIS is a true statement? | NO. it is a false statement. Several types of live attenuated vaccines are
available for use in animals, but they are
considered to be UNSUITABLE for humans. |
| The live inactivated vaccines consisted of a 5% suspension of infected
animal nervous tissue which had been
inactivated (e.g. the Semple vaccine was
derived from phenol-inactivated infected
rabbit brain). These preparations are now out of date as
they were associated with the rare
complication of ? | demyelinating allergic
encephalitis. |
| the Semple vaccine was
derived from phenol-inactivation of which animal tissue? | the Semple vaccine was
derived from phenol-inactivated infected
rabbit brain. |
| This vaccine strain is grown in embryonated duck
eggs and is inactivated with B-propriolactone.
This vaccine has a lower risk of allergic
encephalitis. However, it has a limitation which is? | DUCK EMBRYO VACCINE.
it is considerably less
immunogenic. |
| This vaccine is grown on WI-38 (U.S.) or MRC-5
(Europe) cells. | Human Diploid Cell Vaccine
(HDCV). The vaccine is highly effective, in several
studies, antibodies have been
demonstrated in 100% of all recipients. Serious adverse reactions to HDCV are
extremely rare. |
| the benefit of HDCV | The vaccine is highly effective, in several
studies, antibodies have been
demonstrated in 100% of all recipients. Serious adverse reactions to HDCV are
extremely rare. |
| the limitation of HDCV is? | The vaccine is expensive ( $20 US/doses), as
human cell cultures are more difficult to handle
than other animal cell culture systems.
Five or 6 doses of the vaccine is normally i.m.
Several studies suggest that smaller intradermal
doses of HDCV may be as effective and thus it
may be considered for use in poor developing
countries. |
| In the past, the Scandinavian countries were able to
rid themselves of rabies by ? | In the past, the Scandinavian countries were able to
rid themselves of rabies by sanitary control alone,
which included stray dog control. |
