RNA virus Flashcards
This virus is an enveloped ssRNA and non-segmented genome, filamentous virions (thread-like structure), that causes Ebola hemorrhagic fever.
Ebola virus
There is no cure for this virus, it is acute, no carriers, is transmitted by direct spread, fever, headache, joint and muscle aches, sore throat, and weakness followed by diarrhea, vomiting, and stomach pain,
Ebola virus
This virus is naked ssRNA and is associated with the common cold. Sensitive to acidic environments and has a unique molecular surface makes the development of a vaccine unlikely. Can be acquired from contaminated hands and fomites.
Human Rhinovirus
Positive-sense naked ssRNA
Symptoms: fever, runny nose, sneezing, cough, skin rash, mouth blisters, body, and muscle aches.
Infection occurs via the faecal-oral route.
Enteroviruses
What diseases do Enteroviruses cause?
Coxsackie A16 and EV71-HFMD (lesions and fever)
It is a positive-sense ssRNA and can survive stomach acids when ingested.
Poliovirus and Poliomyelitis
Acute enteroviral infection of the spinal cord and can cause neuromuscular paralysis.
Poliomyelitis
Positive-sense ssRNA, faecal-oral transmission, flu-like symptoms, no specific treatment once the symptoms begin.
Hepatitis A
How does Hepatitis A spread?
Not washing hands, sex with infected partners, eating/drinking contaminated food, and recreational drug use
Belongs to the family of Flaviviridae, an enveloped positive-sense ssRNA, and is transmitted by blood.
Hepatitis C
Liver cirrhosis, liver transplant, and damage are accelerated by alcoholism and drug use.
Hepatitis C
Naked dsRNA and Genus Reoviridae. Pin-wheel-shaped, 11 double-stranded RNA molecules, packaged in capsid proteins and can bind receptors on enterocytes (intestine cells).
Rotavirus
Causes gastroenteritis in children
Rotavirus
Oral-faecal transmission, pass from child to child, incubation time is 2 days and symptoms usually start with vomiting followed by 4-8 days of severe watery diarrhea.
Rotavirus
Positive-sense non-segmented ssRNA. Cruise ship virus. Viral gastroenteritis and stomach flu (Winter Vomiting Disease). Transmitted by the faecal-oral route. Acute onset, nausea, vomiting, cramps, diarrhea, chills.
Caliciviruses
Loose envelope positive-sense ssRNA, caused by a Rubivirus.
Rubella virus
What are the diseases under Rubella?
German measles, Postnatal rubella, and Congenital rubella.
Intense red rashes and transmitted through contact with respiratory secretions
German measles
Positive-sense ssRNA with crown-like spikes on their surface, cold or flu-like symptoms.
Coronavirus
Severe Acute Respiratory Syndrome, Transmitted through droplet or direct contact, fever, body aches, and malaise. Diagnosis-PCR, seroconversion (ELISA or IFA).
SARS
Enveloped ssRNA, encode reverse transcriptase enzyme which makes a DNA copy of their RNA genome.
Retroviruses
Cause of Acquired Immunodeficiency Syndrome (AIDS), infects the immune system including T lymphocytes (CD4+ T cells). Incapacitation of T lymphocytes allows opportunistic pathogens to infect the body. Infects and paralyzes B lymphocytes. Does not survive long outside of the body.
HIV
How is HIV transmitted?
Sexual intercourse, infected mother to her child before or during birth and from breastfeeding, sharing needles, and blood transfusion or organ transplant from an infected person.
The disease cause extreme leukopenia (reduction of WBC in the blood, CD4+ cells in particular), formation of giant T cells and other syncytia (allows the virus to spread directly from cell to cell), infected macrophages release the virus in CNS (toxic effect, inflammation), and destruction on CD4 lymphocytes (allows for opportunistic infections and malignancies).
Effects of HIV infection
What does it mean when T4 cells fall below 200 cells/mm3?
This means that AIDS symptoms appear
Diagnosis of HIV infection
ELISA, detection of antibodies specific to the virus in serum or other fluids.
What are the criteria for AIDS?
Positive for HIV, CD4 count lower than 200 cells/mm3 of blood and lower than 14% of all lymphocytes.
What is the treatment for HIV?
AZT. It interferes with the reverse transcriptase activity of the virus. HAART is when the virus is resistant to some antivirals and reduces the risk of HIV transmission and can extend the life of patients by about 8 years.
What are the important laboratory investigations for HIV?
Coinfections (check for syphilis, Hep A, B, and C serology)
Chest X-Ray (To look for TB)
Full blood count
ECG
Fasting lipid profile
Blood sugar
Liver function test
Renal function test
Serum lactate
Cervical pap smear for women
Paramyxoviruses is an enveloped ssRNA and is transmitted by respiratory droplets. What are the families under this virus?
Parainfluenza, mumps, morbillivirus (measles), and pneumovirus (RSV)..
Red measles and rubeola, very contagious, transmitted by respiratory aerosols, human is the only reservoir. Sore throat, dry cough, headache, conjunctivitis, lymphadenitis, fever, koplik spots, oral lesions, and rash. Most serious complication is SSPE (meningitis layer). Leads to coma and death. Attenuated viral vaccine is MMR.
Measles
Respiratory transmission, seen mostly in children, minor cold, bronchitis, bronchopneumonia, and croup (coughing, barking sounds).
Parainfluenza
Infects the upper respiratory tract, and produces giant multinucleate cells, rhinitis, wheezing, otitis, and croup.
RSV
Rhabdovirus family, Bullet-shaped virions, enveloped RNA, slow progressive zoonotic disease
Rabies
The virus enters through bite, grows at trauma site for a week. Enters nerve endings and advances toward the ganglia, spinal cord and brain which could cause neurological problems.
Rabies
What are the two forms of rabies?
Dumb form (non-responsive, paralyzed, stuporous) and Furious form (hydrophobia, fear of water, seizures, twitching)
What are the two types of spikes in Influenza?
Haemagglutinin (H) helps the virus attach and penetrate host cells.
Neuraminidase (N) helps release the virus from the host cell after replication and assembly.
Acute, highly contagious respiratory illness.
Causes rapid shedding of cells, stripping respiratory epithelium, and severe inflammation.
Fever, headache, myalgia, pharyngeal pain, shortness of breath, coughing.
Influenza A
What are the diseases in immunocompromised people for Influenza?
Guillain-Barre syndrome (occurs when the body damages its own peripheral nerve cells)
Reye syndrome (often occurs in children who take aspirin to treat pain and fever) , enlargement of brain and liver.
