Lecture 5 6 7

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Questions and Answers

What is the primary mode of transmission for Hepatitis C?

Contact with contaminated food

Bodily fluids like semen and vaginal discharge (correct)

Airborne transmission

Insect bites

Which of the following symptoms is most commonly associated with Zika virus infection?

Joint pain only

Jaundice

Fever and rash (correct)

Gray-colored bowel movements

Which complication is NOT commonly associated with Zika virus infection during pregnancy?

Microcephaly

Severe brain defects

Guillain-Barré syndrome (correct)

Miscarriage

What percentage of chronically infected Hepatitis C patients develop chronic liver disease?

60-70% Signup and view all the answers

What is the primary vector for transmitting Japanese encephalitis virus?

Culex mosquitoes Signup and view all the answers

Which treatment is NOT used for Hepatitis C?

Antibiotics Signup and view all the answers

What preventive measure is recommended for avoiding Zika virus infection?

Using mosquito repellents and condoms during sex Signup and view all the answers

What is a common symptom of acute Hepatitis C infection?

Abdominal pain Signup and view all the answers

What is one way that rhabdoviruses inhibit host systems?

Inhibit transcription by host RNA polymerase Signup and view all the answers

How do influenza viruses such as Influenza A and B primarily transmit between individuals?

Droplets made during coughing or sneezing Signup and view all the answers

What causes the rapid mutation of influenza viruses?

Lack of proofreading ability in RNA-dependent RNA polymerases Signup and view all the answers

Which of the following is NOT a symptom commonly associated with influenza?

Severe abdominal pain Signup and view all the answers

What factor can influence the severity of flu seasons?

Matching of flu vaccine to circulating viruses Signup and view all the answers

Which influenza virus subtype is NOT mentioned as having the potential to infect humans?

H4N1 Signup and view all the answers

What is a direct consequence of the high mutation rate in influenza viruses?

Yearly formation of new virus subtypes Signup and view all the answers

What is the approximate mortality rate associated with Covid-19?

1.4 - 3.4% Signup and view all the answers

Which of the following symptoms is NOT commonly associated with Covid-19?

Rash Signup and view all the answers

Which of the following is a method of transmission for the Rubella virus?

Coughing and sneezing Signup and view all the answers

Which group is most at risk for serious consequences from infections of the Rubella virus?

Pregnant women Signup and view all the answers

Which of the following alphaviruses is specifically associated with causing fever, arthralgia, and rash?

Chikungunya virus Signup and view all the answers

What is the primary mode of transmission for Old World alphaviruses?

Infected mosquito bites Signup and view all the answers

Which of the following could be a result of congenital rubella syndrome?

Vision impairment Signup and view all the answers

What do the New World alphaviruses primarily cause?

Encephalitis Signup and view all the answers

Which of the following is a characteristic of infection by alphaviruses?

Often occurs without clinical disease Signup and view all the answers

What preventive measure is effective against the Rubella virus?

Vaccination Signup and view all the answers

What condition is primarily caused by transmission from wild animals to livestock in endemic regions?

Rabies Signup and view all the answers

What is the maximum incubation period for rabies in wild animals as described?

3 months Signup and view all the answers

What initial symptoms might a patient with furious rabies experience?

Headache and irritability Signup and view all the answers

What physiological response occurs during the excitement stage of furious rabies?

Painful muscle spasms Signup and view all the answers

Which animal is most commonly associated with rabies transmission in endemic areas?

Dogs Signup and view all the answers

What action is important for farmers to take to prevent rabies in areas near jungles?

Vaccinate livestock regularly Signup and view all the answers

What common misconception about rabies can lead to its spread in rural areas?

It can only be transmitted by domestic animals Signup and view all the answers

What is one of the first signs that the virus has reached the central nervous system (CNS) in furious rabies?

Headache Signup and view all the answers

In which region is rabies transmission particularly noted among wild animals and domestic pets?

Southeast Asia Signup and view all the answers

What preventive measure is essential for managing rabies in endemic regions?

Early treatment after exposure Signup and view all the answers

What is a hallmark symptom of rabies in its clinical stage?

Hydrophobia Signup and view all the answers

Which treatment method is recommended immediately after a potential rabies exposure?

Extensive wound washing Signup and view all the answers

What is the appropriate post-exposure prophylaxis for Category II rabies exposure?

Immediate vaccination and local treatment Signup and view all the answers

Which group of individuals has no contraindications to receive post-exposure prophylaxis (PEP) for rabies?

Infants and pregnant women Signup and view all the answers

What type of rabies progression is described as 'Dumb rabies'?

Steady, quiet decline with paralysis Signup and view all the answers

What measure has helped maintain the UK's status of absence of rabies?

Quarantine of animals Signup and view all the answers

Which of the following is not a category of exposure according to rabies protocols?

Category IV Signup and view all the answers

How does the rabies virus primarily transmit from animals to humans?

Through direct contact with saliva Signup and view all the answers

What happens to patients with rabies once clinical disease manifests?

They experience a rapid and relentless progression to death Signup and view all the answers

What vaccination program can substitute quarantine measures for pets entering the UK?

Pet passport scheme with microchip and vaccination Signup and view all the answers

Study Notes

Learning Outcomes for Lecture 6: DSRNA Viruses

Students will be able to describe the pathogenesis of Reoviridae, specifically rotavirus.

Reoviridae Family

Reovirus, a family of viruses found in human and animal respiratory and enteric tracts.
Infections are frequently asymptomatic.
Rotavirus is the most studied member of this family.
It causes gastroenteritis.
Rotavirus is resistant to chlorine treatment.
Rotavirus infections are easily transmitted between animals and humans.

Rotavirus Virion

Rotavirus virion is comprised of 3 layers of capsids: inner, intermediate, and outer.
Isolated from fecal samples from humans and animals
The virion is naked and icosahedral.
It has 11 RNA segments.
Channels are present in the inner and intermediate layers of the capside for RNA transcript movement.

Why is Rotavirus Triple Layered?

Double-stranded RNA (dsRNA) is a potent inducer of apoptosis, interferon production, and RNA silencing.
The enclosed dsRNA in the rotavirus structure protects it from these effects.
Transcription of the dsRNA in rotavirus happens in the inner capside layer rather than the cytoplasm.
It is difficult for the RNA to be released to the surrounding environment due to strong inflammatory responses.

Rotavirus Disease

Rotavirus contributes to a significant number of infant and young children's deaths yearly.
In Malaysia, it is estimated to be 22-50% of all diarrheal cases in children.
Enterocytes on the villi of the small intestine are destroyed.
Rotavirus causes a decrease in the absorption of water, sugar, and salts.
It inhibits water and salts' absorption, resulting in diarrhea and dehydration.
Treatment involves rehydration through sugar and salts.

Rotavirus Infection Anatomy

The rotavirus infects the villous epithelium of the small intestine, especially the proximal areas.
The virus replicates and releases infectious particles in the distal small intestine.
The primary symptom is induced by the viral enterotoxin NSP4.
The virus can easily infect older individuals due to immunodeficiency.

Learning Outcomes for Lecture 7: (+) ssRNA Viruses

Students will be able to describe the pathogenesis of (+) ssRNA viruses.

Picornaviridae Family

A family of small RNA viruses infecting humans and animals.
Known genera of picornaviruses include hepatovirus (liver), enterovirus (intestine), rhinovirus (nose), and aphthovirus (vesicles in mouths).
Different picornavirus types infect different parts of the body.

Picornavirus Diseases

Hepatitis A virus is a significant cause of liver infection.
Polio virus is responsible for polio, which can cause paralysis and other neurological complications.
Coxsackieviruses cause diseases such as hand-foot-and-mouth disease, and similar syndromes.
Enterovirus 70 and 71 can cause diseases prevalent in East Asia and Southeast Asia.
Rhinovirus is responsible for common cold.
Foot and mouth disease is a foot-and-mouth disease in livestock and mammals.

Picornaviruses HiJack Host Systems

They inhibit the host's protein synthesis, transcription process by blocking RNA polymerase and transportation of host mRNA.

Flaviviridae Family

The family of viruses includes West Nile virus, dengue virus, and yellow fever virus.
West Nile virus is most commonly encountered in the Northern part of the Americas.
West Nile causes brain infections which may lead to death or severe neurological problems such as encephalitis, and meningitis.
Dengue virus is spread by the Aedes mosquito.
Yellow fever is spread to humans from mosquitos.
It can be potentially fatal.

Coronaviridae Family

This family of viruses infects humans, commonly causing mild respiratory symptoms.
The viruses have been identified to cause SARS, MERS, and Covid-19 (Coronavirus disease 2019).
Symptoms include high fever, headache, body aches, diarrhea, dry cough.
Primarily spread by close contact.

Togaviridae Family

This family includes viruses such as equine encephalitis viruses and Chikungunya viruses.
These viruses are spread by mosquitoes.
Symptoms include fever, rash, headache, and arthralgia (joint pain).
The most common symptom includes fever, malaise, headache.

Rubella Virus (German Measles)

Unvaccinated children and young adults are susceptible to rubella.
It can have serious consequences, including miscarriages and causing congenital defects.
The infection is spread through coughing and sneezing.
Preventable by vaccination.

Rhabdoviridae Family

This family includes viruses such as rabies viruses.
The viruses infect mammals, fish, plants, and insects.
The viruses are spread through bites from infected animals.
Common illnesses caused by the viruses include encephalitis.
Two types of rabies exist and include furious rabies characterized by symptoms such as headache, fever, irritability, restless, anxiety and dumb rabies characterized by paralysis and a steady decline in the patient's health.
Rabies can be treated if detected earlier.
The viruses block host systems by inhibiting host protein synthesis, by inhibiting transcription by host RNA polymerase.
They also block intracellular transport of host mRNA and inhibit interferon synthesis.

Orthomyxoviridae Family

This family includes viruses such as influenza A and B viruses.
These viruses cause seasonal flu epidemics.
The viruses' high mutation rate causes a significant error rate during viral genome replication.
The genes responsible for the surface proteins contribute to the development of various subtypes (eg. H1N1, H3N2, H5N1, H7N9).
Transmission occurs through respiratory droplets via sneezing and coughing.
Symptoms include fever, cough, sore throat, body aches, fatigue, headaches, and occasionally, vomiting, and diarrhea, especially in children.
There is no known cure for the flu.

Paramyxoviridae Family

This family includes viruses like measles virus.
It is a highly contagious respiratory disease spread through contaminated air droplets.
Prevention requires a high percentage of herd immunity.
Symptoms including fever, runny nose, cough, red eyes, rash all over the body.
Some of the complications can include pneumonia, diarrhea, and ear infections, prevalent in adults and children.
It is preventable by vaccination.

Henipavirus

Henipaviruses are found in bats and pigs and can be passed from these animals to humans.
Some symptoms include encephalitis and respiratory-related illness.
Prevention involves preventing contact with animals (especially pigs) and practicing proper sanitation.

Filoviridae Family

This family of viruses includes Ebola and Marburg viruses.
It is a cause of severe haemorrhagic fevers with a high fatality rate.
Transmission occurs through contact with an infected animal or via bodily fluid contact with an infected individual.
It can be transmitted from an animal to another animal through contact.

Bunyaviridae Family

This family of viruses includes certain hantaviruses found in Asia and the New World.
The viruses can lead to haemorrhagic fever, particularly Renal Syndrome (HFRS) and the Pulmonary Syndrome (HPS).
The first identified hantavirus was Sin Nombre.
Rodent control is a key strategy to prevent Hantavirus infections.

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Description

This quiz covers key learning outcomes from Lecture 6 on the Reoviridae family, focusing primarily on rotavirus. Students will explore the pathogenesis, structure, and clinical significance of rotavirus infections. Enhance your understanding of this important virus and its impact on human and animal health.