Viral Encephalitis

Describe the clinical picture for vest nile virus (sypmyoms). Where do we have the highest number of cases in the US?

90% of patients present with fever, most present with fatigue and altered mental status and headache In the US, most cases were in CA, TX, and NE. NY had 23 cases in 2014.

Who do we give the Zoster vaccine to? What percentage of individuals will get zoster in their lifetime? What percent of these will develop PHN and/or eye involvement? Is the vaccine a live attenuated, or a enzyme vaccine, or an antibody vaccine? Whats different between this and the veracella vaccine?

About 1 in 3 individuals will develop zoster in their lifetime and about 10-20% of these will develop PHN and/or have eye involvement. The vaccine for zoster is given to people age 60+ and it is a live attenuated, one shot virus that gives reasonable protection (2/3 will not have PHN. It uses 14x the potency of the varicella vaccine but offers the same preparation.

Alpha and Falavi viruses are ______ genome viruses. Bunya are _____.

Alpha and flavi are +ve stranded RNA viruses, and Bunya have -ve stranded RNA, 3 segments

What are the viral arboviruses? What does the name suggest? What are three viruses in this family?

Arboviruses are a family of viruses with severy families including the Alpha [toga], Flavi, and Bunya viruses

What is the animal that usually gives WNV to us? What animal is carried on us that actually gives us the virus?

Birds are the natural host that have Culex picquitoes that are the vector that can spread to fumans .

What are some disadvantages of the OPV poliovirus vaccine? Is it still used as much as it used to be? What about the IPV, does it have any disadvantages?

Disadvantages of the OPV live attenuated virus include its risk of vaccine-associated poliomyelitis (from mutation of the attenuated virus) and spread of the vaccine to contacts without their consent. It is not safe for the immunocompromised patients and it should not be stored. --- Its no longer recommended for use in teh US but is used elsewhere The IPV vacine also has a downside in that no secretory antibodies are made and booster shots are needed to maintain immunity. Higher community immunization levels are required. OPV is no longer recommended in the US but its used elsewhere.

Define encephalitis Define meningitis Define Aseptic meningitis What kind of agents are the most common cause of encephalitis/meningitis?

Encephalitis is defined as inflammation of the brain, while meningitis is defined as inflammation of the membrane s of the brain or spinal cord. Aseptic meningitis is a type of meningitis in which the standard tests for bacteria are negative. Viral infections are the main cause of encephalitis or meningitis, but other agents are also responsible.

What patient population gets encephalitis from HSV2? HSV1? Which one can give you meningitis? Where do HSV1 viral particles lie dormant in? HSV2? - What reactivates them? -What do we need to have to resolve the infection? - What can make our symptoms potentially worse?

HSV infection is caused by direct contact (local infection). Herpes simplex encephalitis is usually caused by HSV1 but neonatal HSV2 infection can also cause herpes simplex encephalitis. Adults HSV2 genital infections can cause herpes simplex meningitis. The latency is established either in the trigeminal (HSV1) and/or sacral (HSV2) neurons. HSV can be reactivated by stress, immune suppression, UV, and reactivations can be frequent. Cell-mediated immunity is needed for resolution of the infection. The immune respoonse contributed to the symptoms that are experiencing (the degree of inflammation).

What is the major cause of viral encephalitis? What else can cause it?

HSV-1 is a major cause of viral encephalitis, as well as picornavirus and raabies virus. HSV-2 virus Causes meningitis, as well as picornavirus and mumps.

What can HSV1 cause in the body? What about HSv2?

HSV1 can cause encephalitis, and will often present with keratoconjunctivitis, oral manigestations, gingivastomatitis, tonsilitis, labialis, pharangitis, esophagitis, Tracheobronchitis, gladiatorum, genital lesions, and herpatic whitlow. HSV2 can cause encephalitis, oral manifestations, pharyngitis, genital symptoms, as well as herpatic whitlow and can cause neonatal HSV.

Does HSV1 cause viral encephalitis? Canc HSV2? What arabout Varicella, what can this cause? For each of these, doe the CNS problems come from primary infections, recurrent, or both?

Herpes virus either HSV-1 and HSV-2 can cause encephalitis/meningitis in 1 in 300,000 people. Disease often occurs from recurrent infections. Varicella zoster virus can cause meningoencephalities and transient neurological signs and pains only with recurrent infection. There are vaccines for varicella zoster virus.

What are some viruses seen in western new york that cause viral encephalitis?

In western New York, the leading causes of viral encephalitis include HSV, enterovirus, HIV. Other possible causes include Western nile virus, CMV, SLE (in Rochester). HTLV-1 is human T-cell luekemia virus (seen with tropical spastic paraparesis.

How does acyclovir cause termination, amking it a good antiviral medication?

It lacks a 3' OH hydroxyl group, causing it to -stop DNA chain elongation

From what vector can you contract Japanese encephalitis? What are the reservoirs? Is there a vaccine?

Japanese encephalitis is an emerging mospquite-borne infeciton in the far east (in India to SE Siberia to NE Australia). It has a 30-40% case to fatality ratio, with about 70k cases per year. Pigs and birds are reservoirs and children are most at risk. Culex spp are vectors for the disease. There are vaccines available for Japenese encephalitis and they are given to those spending 30+ days in an endemic area/ It involves 2 or 3 doses over 30 days. There are two vacines including the JE-MB and the JE-VC vaccine.

How does primary HSV infection often present? How will recurrences after a period of latency often arise?

Oftentimes viral encephalitis will present with primary gingivostomatisis followed by a long latent period. Secondary (recurrent) HSV infection usually will show up as cold sores resulting from reactivation from latency. The virus will lie dormant in the trigeminal nerves.

What are three viruses that are included in the Piconavirus family? How does piliovirus fit into this?

Picornaviruses are a family of several generas of viruses including Enteroviruses Rhinoviruses, and Hepatitis A virus. Poliovirus is a type of enterovirus and can cause postpolio syndrome (neuronal loss). Enteroviruses can cause meningitis and encephalitis. The rhinoviruses are the common cold viruses.

We only have vaccines for one kind of enterovirus. Which one? When was it first introduced? When cant we give it? Why?

Poliovirus This was introduced in 1955 as a dead virus load, and in 1962 as a live attenuated virus with a dramatic effect. Live virus cant be given to people with weakened immune systems.

What are two names for treatments we could do if we are exposed to rabies? How would we decide whether or not to start treatment?

Post exposure: Treat with HDCV or PCECV Decision on whether or not to start treatment depends on the nature of the contact with the animal

Please list the prion diseases that can be obtained from animals. List 6.

Prion diseases from animals include scrapie (from sheeps and goats), transmissible mink encephalopathy, bovine spongiform encephalopathy (BSE), Chronic wasting disease (deer, elk, mules), feline spongiform encephalopathy, and ungulate spngiform encephalopathy.

Please list the prion diseases that can be spread from humans . List 5

Prion diseases infecting humans include Kuru, Creutzfeldt-Jacob Disease (CJD), Variant CJD, Gerstmann-Strausser-Schinkler Syndrome (GSS), and Fatal Familial Insomnia (FFI).

Define what a "prion" is. What causes transmissible spingiform encephalopathy? What type of sanitation techniques are prions resistant to making this a huge concern?

Prions are modified protein products of a cellular gene PrPc. There are no nucleic acids in priors. They used to be called "slow virus diseases". PrPc has an unknown function (possible in nerve repair). It can cause transmissible spongiform encephalopathy (TSE). Prions are resistant to regular autoclaving and can be spread through infection from surgical instruments.

Does the rabies virus have a long incubation time? What is the reservoir for the animal? What is the vector? What are two ways the infection can be spread? Who is most at risk for getting infection?

Rabies is a zoonotic virus with a long incubation period. It is carried by wild animal reservoirs with a wild animal vector (unvaccinated dogs and cats). In NYS there is law that cats, dogs, and ferrets much be vaccinated. Bat contact is also a risk. The source of infection can be via salivary route or via aerosols. Veterinarians, animal handlers, and anyone bitten by a rapid animal and those in countries with no pet vaccination programs are at risk.

There are several flaviviruses that are also of importance including St. Louis encephalitis (SLE), Tick borne encephalitis, Powassan (TBE) virus, and others. Where is St Louis encephalitis most common? Whats the mortality of Tick Born encephalitis like? Is there a TBE vaccine? Where is it useD?

St. Louis encephalitis (SLE) occurs in sporatic outbreaks such as the 1975 outbreak in Texas. It can be confused with west nile encephalitis Tick-borne encephalitis is widespread across asia and europe and can have a 1-10% fatality Powassan encephalitis(TBE) is in the US and Candada and have caused 17 cases since 2013 and was the subject of concern in the spring of 2015. There is a widely used TBE vaccine in Europe. Its incidence of infection has dwindled since the 1975 outbreak.

What are 4 kinds of viruses that fit into the enterovirus genus?

The Enterovirus genus can be broken down into (1) Echovirus (2) Coxsackie virus, Enterovirus, and Poliovirus. Enterovirus can be diagnosed using RTPCR of colected spinal fluid.

What are the current US poliovirus vaccine recommendations in the US? How common is polio in the world? There were only 400 cases in 2014. What countries still have some cases?

The US polio vaccine recommendations recommend IPV given 2, 4, 6-18 months, and between years 4-6. Most of the polio is gone from the world because of the OPV vaccine. In 1988 it was endemic in 125 countries with >350K cases. By 2014 there were about 400 cases (in Pakistan, Afghanistan and Nigeria). No longer India. Recent outbreaks in Somalia, Kenya, and Syria. There are over 2 billion doses of OPV given annually.

Are there any vaccinations to WNV? What about antiviral treatments?

The WNV was thought to have been isolated from a bird virus. WNV isolates from two Israelis in tTel Aviv were shown to be 99.9% identical to avian strains circulating in Israel and avian strains circulating in NY. It is now in all US states and in Canada and Mexico. There are no vaccines and no antiviral agents.

What are the chief bacteria that can cause bacterial meningitis?

The chief bacteria that can cause bacterial meningitis are Strep pneumoniae, N. meningitidis, Listeria monocytogenes, H. influenzae b, and B. burgdorferi.

Explain the morphology of the herpesvirus. What surrounds the genetic material? Does it have any protein that are important? What type of genetic material does it contain?

The herpesvirus has an envelope with viral glycoproteins coating the envelope. It has a capsid surrounding a DNA core, and the capsid is made out of capsomere protein subunits.

What is the live attenuated polio vaccine called? What about the killed vaccine? What are the advantages for having both kinds?

The live attenuated polio vaccine is called the OPV vaccine. It is effective and provides long lasting immunity. It involves induction of secretory antibodies. The killed virus vaccine is the IPV vaccine. It is stable and safe to give to IC patients. It cannot cause disease.

Is there a rabies vaccine? Does it require a ton of shots? When would we typically vaccinate? Would we ever give this if you have already been bitten?

The rabies vaccine is safe but expensive. It can be given post-exposure. When you vaccinate can depend on the exposure situation. If you are bitten by an animal it is recommended. Pre-exposure the vaccine consists of 3 shots at days 0, 7, and 21-28. Post exposure you would get 4 shots in days (0, 3, 7, 14 + RIG) and 2 shots if already vaccinated at (0 and 3 days). Rabies is rare in the US, with 50 cases since 1990.

Rabodies is a member of what kind of virus family? How do we usually get the virus? WHow does it Spread to the CNS? What structures in the CNS can be affected?

The rabies virus is a member of the rhabdovirus family. The virus is usually inoculated from an animal bite and virions enter the peripheral NS and passively ascend the sensory fibers. They replicate in the dorsal ganglion and ascent the spinal cord rapidly, infecting the spinal cord, brainstem, cerebellus and other structures, and could cause descending infection to the eye, salivary glands, skin, and other organs.

Do we have antiviral treatments for VZV? what are two that we use? How do they work?

There are excellent antiviral treatments available to treat both HSV1 and VZV infections. Acyclovir (ACV) and its derivaties (including Valtrex) stop the synthesis of viral DNA specifically. Acyclovir lacks a 3' OH group to stop DNA chains from elongating. Foscarnet (phosphonoformate) can be used for acyclivir resistant strains by acting on the viral DNA polymerase.

What is the common route of innoculation that the rhinovirus, echovirus, coxsackie and poliovirus and HAV all take to get into the body? what can block their spread? How do they travel to other tissues and what tissues do they usually travel to?

They all enter into the nasal or oral mucosa and replicate in the oropharynx and primarily spreads via the blood stream but spread can be blocked by antibody blockage before reaching the target tissue. This target tissue could be the skin, muscle, brain, meninges, or liver, and could later cause a secondary viremia.

If we want to diagnose HSV encephalitis, waht should we make sure to do? After establishing that there are clinical signs such as flu-like symptoms, confusion, gait distrubrances, ect, what should we rule out? What would be our next step?

To diagnose HSV encephalitis, clinical flu-like signs, confusion, gait abornamalities can be detected and should raise suspission. You must rule out space-filling lesions. A spinaal tap should be performed and should not have any bacteria. The CSF can be send for PCR analysis. It is very important to start viral therapy ASAP. The majority of the encephalitis deaths in the US are caused by HSV?

How is VZV transmitted? Where does it establish latency? When is it reactivated? In what population does it occur? How frequently?

VXV is transmitted by respiratory droplets or via direct contact, causing a systemic infection. The virus establishes latent infection in a variety of spinal ganglia and reactivates following depressed immune response. Reactivation often occurs only once, usually in older people.

Do we have vaccines for VZV? When do we give the varicella one? When do we give the zoster one?

Vacines for varicella and zoster are available. Varicella (is given at 1 year and again at 4-6 years. Zoster is given at any time to people <60 years old. Patients with post-herpetic neuralgia can also undergo pain management therapy.

Chicken pox is? A recurrent infection can come back as?

Varicella After primary infection it can lie dormant A recurrent infection can come back as shingles (zoster).

Define viral encephalitis. How is it caused pathologically? How does it the virus get into the CNS>

Viral encephalitis is inflammation of the CNS caused by viral growth in the CNS. Pathologically it is caused by neural cell death and dysfunction either due to viral growth, activation of the innate immune response (aB induction or IFN), or via activation of cytotic T-cell responses or apoptosis. The virus gets to the CNS hematogenously, or throgh retrograde neural transmission.

Prions are impervious to standard disinfection procedures. What can we use to sterilize? Can prions diseases have long incubation periods once contracted? How can we contract prion diseases? Are there any that are genetic? How common is Crutzfield-Jakob disease in the US?

You can cleanse with NaOH or autoclave for 4.5 hours at 134C. Prion diseases, once inoculated have incubation periods as long as 30 years. Transmission can occur through infected tissue or could be due to genetics. Infection occurs through open cuts in the skin, transplantation, ingestion, or through the blood. About 250 cases per year in the US develop CJD.

The alphavirus belongs to the arbovirus family and is also called the _____ virus What are two complications of alphavirus infections? Where did each start?

toga virus = alpha virus. Alphavirus infections include: (1) Chikungunya outbreak (started in India in 2005) with >1,500,000 cases, and has spread to the far east, central and South Africa and France. (2) EEE (Eastern equine) US eastern seabord and great lakes and swampy regions. Horses also get this.