عائشة Virus Flashcards
RHABDOVIRUSES RABIES VIRUS
Disease: This virus causes ….
rabies, an encephalitis.
Rabies virus It has a …… enclosed within a ……. surrounded by a ……
single-stranded RNA
bullet-shaped capsid
lipoprotein envelope.
Rabies virus has a …. antigenic type.The antigenicity resides in the …….
single
envelope glycoprotein spikes
Rabies virus attaches to the …. on the cell surface.
acetylcholine receptor
Rabies virus is transmitted by the ….. that manifests aggressive, biting behavior induced by the ….. The virus is in the …. of the rabid animal. I
bite of a rabid animal
viral encephalitis
saliva
…. have been the source of most cases of human rabies in the United States.
bats
…… do not transmit rabies
Rodents and rabbits
MOT of rabies
Rapid animal
Organ transplantation (cornea)(non bite example)
exposure to aerosols of bat secretions containing rabies virus.( non bite example)
Pathogenesis of rabies
The virus multiplies locally at the bite site, infects the sensory neurons, and moves by axonal transport to the central nervous systemThe virus multiplies in the central nervous system and then travels down the peripheral nerves to the salivary glands and other organs. From the salivary glands, it enters the saliva to be transmitted by the bite. There is no viremic stage. Within the central nervous system, encephalitis develops, with the death of neurons and demyelination. Infected neurons contain an eosinophilic cytoplasmic inclusion called a Negri body, which is important in laboratory diagnosis of rabies. Because so few individuals have survived rabies, there is no information regarding immunity to disease upon being bitten again.
The incubation period for rabies is typically ….. but may vary from 1 week to 1 or 2 years, depending on …..
2–3 months
size and site of inoculation
Initial symptoms of rabies include ……. at the wound site
a fever with pain and unusual or unexplained tingling, pricking, or burning sensation (paraesthesia)
There are two forms of the rabies disease:
furious rabies
Paralytic rabies
People with furious rabies exhibit signs of …… Eventually death occurs after a few days due to …..
hyperactivity, excitable behaviour, fever, excitation, dilation of the pupils, salivation, anxiety, hydrophobia, spasms of the throat muscles abnormal behavior, hallucinations, insomnia and, sometimes aerophobia (fear of fresh air).
cardio-respiratory arrest.
Paralytic rabies accounts for about …….. This form of rabies runs a less dramatic and usually longer course than the ….. Muscles ……… The paralytic form of rabies is often misdiagnosed, contributing to the under-reporting of the disease.
20% of the total number of human cases
furious form
gradually become paralyzed, starting at the site of the bite or scratch. A coma slowly develops, and eventually death occurs.
Laboratory Diagnosis
Rapid diagnosis of rabies infection
In animal by using either PCR assay, fluorescent antibody to rabies virus, or histologic staining of Negri bodies in the cytoplasm of hippocampal neurons.
Rabies in humans can be diagnosed by PCR assay; by fluorescent antibody
by isolation of the virus from sources such as saliva, spinal fluid, and brain tissue
Negri bodies can be demonstrated in corneal scrapings and in autopsy specimens of the brain.
There are two approaches to prevention of rabies in humans:
preexposure and postexposure immunization.
Preexposure immunization with rabies vaccine should be given to ….
individuals in high-risk groups
. Preexposure immunization consists of ….. given on days ….
three doses
0, 7, and 21 or 28.
Postexposure immunization involves the use of both the ……..) plus immediate cleaning of the wound. This is an example of ….
… immunization should also be considered.
vaccine and human rabies immune globulin (RIG, obtained from hyperimmunized persons
passive–active immunization.
Tetanus
Hospital personnel exposed to a patient with rabies need not be immunized unless a significant exposure has occurred (e.g., a traumatic wound to the health care worker). If the decision is to immunize, both …….
. As much as possible of the RIG is given into the bite site, and the remainder is given intramuscularly.
HDCV and RIG are recommended. Five doses of HDCV are given (on days 0, 3, 7, 14, and 28), but RIG is given only once with the first dose of HDCV (at a different site). HDCV and RIG are given at different sites to prevent neutralization of the virus in the vaccine by the antibody in the RIG
Togaviruses
This virus causes …..
rubella and congenital rubella syndrome. Congenital rubella syndrome is characterized by congenital malformations.
Rubella virus is a member of the …
togavirus family.
Rubella virus is a member of the …. It is composed of one piece of ….
However, unlike the paramyxoviruses, such as measles and mumps viruses, it has …
togavirus family
single-stranded RNA, an icosahedral nucleocapsid, and a lipoprotein envelope.
a positive-strand RNA
RUBELLA VIRUS has a .. . antigenic type
single
RUBELLA VIRUS
The virus is transmitted via … and from… transplacentally
respiratory droplets
mother to fetus
…. is a much more common cause of congenital malformations in the United States than is rubella virus.
cytomegalovirus
RUBELLA VIRUS
Initial replication of the virus occurs in the …
The origin of the rash is unclear; it may be due to …
similar rashes are caused by other viruses, such as …
nasopharynx and local lymph nodes.
antigen/antibody–mediated vasculitis.
Coxsackie viruses and echoviruses.
Rubella is a milder, shorter disease than … After an incubation period of…
….. is characteristic.
measles
14 to 21 days
Posterior auricular lymphadenopathy
Congenital Rubella Syndrome The significance of rubella virus is not as a cause of mild childhood disease but as…
a teratogen.
Congenital Rubella Syndrome
When a nonimmune pregnant woman is infected during the …., significant congenital malformations can occur as a result of . …
Rubella can cause congenital rubella syndrome in the newly born. The syndrome (CRS) follows intrauterine infection by … ,and comprises cardiac, cerebral, ophthalmic and auditory defects. It may also cause ….risk of major defects or organogenesis
is highest for infection in the ..
CRS is the main reason a … for rubella was developed. Many mothers who contract rubella within the first critical trimester either have a miscarriage or a still born baby. If the baby survives the infection, it can be born with ….
first trimester, especially the first month
maternal viremia and fetal infection
Rubella virus
prematurity, low birth weight, and neonatal thrombocytopenia, anaemia and hepatitis.
first trimester.
vaccine
severe heart disorders (PDA being the most common), blindness, deafness, or other life threatening organ disorders. The skin manifestations are called “blueberry muff
Rubella Diagnosis
Rubella virus specific …
characteristic .. confirms the diagnosis.
IgM antibodies
rash
MRR is a combination vaccine that protects against …
measles, mumps, and rubella.
using …. before marriage for girls is the only protective measure. Vaccination should be avoided during …
living attenuated Rubella(alone)
pregnancy and for 3 months before pregnancy
Arenaviruses are ….. viruses that cause chronic infections in rodents and …. in humans through rodent excreta, especially urine.
single-stranded ribonucleic acid (RNA) negative sense
zoonotically acquired disease
LASSA FEVER VIRUS
. It causes a … characterized by multiorgan involvement. The disease begins slowly with … and progresses to involve the …. A petechial rash and gastrointestinal tract hemorrhage ensue, followed by death from ….
severe, often fatal hemorrhagic fever
fever, headache, vomiting, and diarrhea
lungs, heart, kidneys, and brain.
vascular collapse.
The natural host for Lassa fever virus is the …..
small rodent Mastomys,
LASSA FEVER VIRUS
…… reduces the mortality rate if given early, and …… obtained from persons who have recovered from the disease, has been beneficial in some cases. No ….. is available
Ribavirin
hyperimmune serum,
vaccine
Lymphocytic choriomeningitis virus is a member of the …….
.The usual picture consists of ……. Spinal fluid shows an increased number of cells, mostly ……
arenavirus family
fever, headache, vomiting, stiff neck, and changes in mental status
lymphocytes, with an elevated protein level and a normal or low sugar level.
Hantaviruses are members of the …… The prototype virus is ….. the cause of …….(KHF)
. KHF is characterized by ……
bunyavirus family
Hantaan virus,
Korean hemorrhagic fever
headache, petechial hemorrhages, shock, and renal failure.
Hantaviruses are part of a heterogeneous group of viruses called ….., which stands for “…… Roboviruses are …..
roboviruses
rodent-borne” viruses.
transmitted from rodents directly (without an arthropod vector)
Rift Valley Fever (ARBO Virus)
an …….,disease that was first reported in the rift valley of Kenya where … suffered from fatal hepatic necrosis and abortion
epizootic
sheep
Rift Valley Fever (ARBO Virus)
After a brief incubation period of ,…. fever, …. Patients tend to progress to one of three final complications: …
2-6 days
severe headache, photophobia, and generalized myalgia begins.
mild encephalitis, retinitis, or hemorrhagic fever.
Rift Valley Fever
the virus is transmitted by many species of . …. and may also be transmitted by …….
mosquitos
fomites, direct contact and by arthropods.
Rift Valley Feve
No … is available
human vaccine
Unconventional slow viruses,
prions
Prions are …. containing particles with no … .. that are highly resistant to inactivation by heat, formaldehyde, and ultraviolet light at doses that ill inactivate viruses
protein
detectable nucleic acid
Kuru is a rare and …. that occurred at epidemic levels during the 1950s-60s among the Fore people in the highlands of New Guinea. The disease was the result of ……., in which relatives prepared and consumed the tissues (……….of deceased family members.
fatal brain disorder
the practice of ritualistic cannibalism among the Fore
including brain)
Kuru belongs to a class of infectious diseases called ….. also known as ….The hallmark of a TSE disease is ……
Scientists believe that misshapen prion proteins have the ability to change their shape and cause other proteins of the same type to also change shape.
transmissible spongiform encephalopathies (TSEs),
prion diseases.
misshapen protein molecules that clump together and accumulate in brain tissue
There were no treatments that could control or cure …., other than discouraging the practice of cannibalism.
kuru
Creutzfeldt-Jakob disease is a ……… Symptoms of Creutzfeldt-Jakob disease (CJD) sometimes resemble those of ….., but Creutzfeldt-Jakob disease usually progresses much more rapidly.
degenerative brain disorder that leads to dementia and, ultimately, death
other dementia-like brain disorders, such as Alzheimer’s
….) — after eating meat from diseased cattle.
variant CJD (vCJD
Initial signs and symptoms of CJD typically include:
Personality changes, Anxiety, Depression, Memory loss, Impaired thinking , Blurred vision, Insomnia, Difficulty speaking, Difficulty swallowing.