Antivirals for the treatment of influenza, herpes, hepatitis and HIV infection Flashcards
Describe the structure of viruses
- Nucleic acid core (DNA or RNA)
- Protein coat - structural (capsid)
- Enzymes within virus (non structural proteins)
- Some also have a lipid envelope
What type of viruses do acute infections tend to be caused by?
RNA viruses
e.g. Influenza, measles, mumps, hepatitis A virus
What type of viruses do chronic infections tend to be caused by?
Generally DNA viruses
- Latent with (or without) recurrences
- Persistent
What are examples of latent with (or without) recurrences viral infections?
Herpes simplex, Cytomegalovirus
What are examples of persistent viral infections?
HIV, HTLV, Hepatitis B virus, Hepatitis C virus
What is a viral syndrome?
Viral syndrome is a term used for symptoms of an infection caused by a virus.
What are examples of viral syndromes?
Rashes, respiratory infections, gastroenteritis, neurological disease
What are 2 types of rashes caused by viruses?
- Non-vesicular rashes
2. Vesicular rashes
What is a vesicular rash?
When a rash appears in the same place as multiple vesicles, it’s known as a vesicular rash
What viral infections cause a vesicular rash?
- Chickenpox (HHV3)
- Herpes simples (HHV1/2)
- Enterovirus
What viral infections cause a non vesicular rash?
Measles Rubella Parvovirus Adenovirus HHV6
Describe a vesicular rash
Fluid filled
Which viral infections can cause respiratory infections?
Influenza A/B Respiratory Syncytial Virus Parainfluenza virus Human Metapneumovirus Rhinovirus Coronavirus (including SARS)
What viral infections can cause gastroenteritis?
Rotavirus Norovirus Astrovirus Sapovirus Adenovirus (group F)
What viral infections can cause neurological disease?
Encephalitis/Meningitis caused by: HSV Enteroviruses Rabies Japanese encephalitis virus Nipah Virus
What viruses are blood-borne?
Hepatitis viruses:
HBV
HCV
Retroviruses:
HIV 1,2
HTLV 1,2
What is encephalitis?
Inflammation of the brain. There are several causes, but the most common is a viral infection.
e.g. Herpes simplex encephalitis (HSE)
What is a disseminated infection?
One in which a localised infection spreads (disseminates) from one area of the body to other organ systems.
When should antivirals be used?
- Acute infections in general population (where high risk of complications)
- Chronic infections eg. HIV, HBV, HCV
- Infections in immunocompromised
What are the most effective medications available for people infected with HSV?
Antiviral medications, such as acyclovir, famciclovir, and valacyclovir
N.B. These can help to reduce the severity and frequency of symptoms, but cannot cure the infection.
What invasive diseases can HSV lead to?
- Encephalitis
2. Disseminated HSV
What should be used to treat Herpes simplex encephalitis (HSE)?
Acyclovir
Who is disseminated HSV seen in?
immunocompromised and neonates (who have acquired it from mother)
What is used to treat frequent reactivations of HSV?
Acyclovir prophylaxis
What drug is used in treatment of chickenpox and shingles (VZV)?
Aciclovir
What virus causes chickenpox and shingles?
Varicella Zoster Virus
When should patients with chickenpox be treated with aciclovir?
> 13 as can get very severe
When should patients with shingles be treated?
- > 60 –> to reduce incidence of post-herpetic neuralgia
- If shingles involves the eye (any age)
- In the immunocompromised
What is post-herpetic neuralgia?
Lasting nerve pain in an area previously affected by shingles.
More likely to occur the older you are when you get shingles
What are the treatments for influenza?
Neuraminidase inhibitors oseltamivir (oral) and zanamavir (inhaled)
These only tend to work if given within 48 hours of onset of symptoms - after this the immune system tends to deal with it