Chickenpox

Chickenpox is caused by the varicella-zoster virus (VZV), also known as human herpes virus 3 (HHV-3)

Chickenpox is highly infectious and spreads from person to person by direct contact or through the air from an infected person’s coughing or sneezing
A persons with chickenpox is contagious 1-2 days before the rash appears and until all blisters have formed scabs It takes 5- 10 days

0-21 days after contact with an infected person for someone to develop chickenpox

start as a 2-4 mm red papule which develops an irregular outline (rose petal).

A thin-walled, clear vesicle (dew drop) develops on top of the area of redness. This "dew drop on a rose petal" lesion is very characteristic for chicken pox

After about 8-12 hours the fluid in the vesicle gets cloudy and the vesicle breaks leaving a crust.

The fluid is highly contagious, but once the lesion crusts over, it is not considered contagious. The crust usually falls off after 7 days sometimes leaving a craterlike scar

Vaccination

Routine vaccination against varicella zoster virus has dramatically reduced the incidence of disease

Herpes simplex virus

The herpes simplex virus (HSV) (also known as Cold Sore, Night Fever, or Fever Blister) is a virus that manifests itself in two common viral infections, each marked by painful, watery blisters in the skin or mucous membranes (such as the mouth or lips) or on the genitals

the two most common are type 1 (HSV-1) and type 2 (HSV-2). HSV-1 is more common and generally considered to be associated with orofacial infection, usually the lips

HSV-2 is associated with the infection of the genitals, although both types can affect either region. HSV-2 infection is of particular concern because of the largely asymptomatic nature of the infection, and the shedding of infective virions even in asymptomatic individuals.

Orofacial infection

Prodromal symptoms

Skin appears irritated

Sore or cluster of fluid-filled blisters appear

Lesion begins to heal, usually without scarring

These infections usually occur on lips especially near the vermilion border. Rarely will a cold sore appear inside the mouth. The sores may appear to be either weeping or dry, and may resemble a pimple, insect bite, or lesion. Vesicles may also appear on the fingers, an infection called whitlow.

Genital infection

Prodromal symptoms

Sore appears

Lesion begins to heal, usually without scarring

In men, the lesions may occur on the shaft of the penis, in the genital region, on the inner thigh, buttocks, or anus. In women, lesions may occur on or near the pubis, labia, clitoris, vulva, buttocks, or anus

Treatments

antiviral medications for controlling herpes outbreaks, including acyclovir (Zovirax), valacyclovir (Valtrex), famcyclovir (Famvir), and pencyclovir

All drugs in this class depend on the activity of the viral thymidine kinase to convert the drug to a monophosphate form and subsequently interfere with viral DNA replication.

Pencyclovir's primary advantage over acyclovir is that it has a far longer cellular half-life

Docosanol works by preventing the virus from fusing to cell membranes, thus barring entry into the cell for the virus

Tromantadine is another antiviral drug effective against herpes.

Herpes zoster

Herpes zoster, colloquially known as shingles, is the reactivation of varicella zoster virus, leading to a crop of painful blisters over the area of a dermatome

Signs and symptoms

pain is the first symptom. This pain can be characterized as stinging, tingling, numbing, or throbbing, and can be pronounced with quick stabs of intensity.

Then 2-3 crops of red lesions develop, which gradually turn into small blisters filled with serous fluid.

Shingles blisters are unusual in that they only appear on one side of the body . That is because the chickenpox virus can remain dormant for decades, and does so inside the spinal column or a nerve fiber.

If it reactivates as shingles, it affects only a single nerve fiber, or ganglion, which can radiate to only one side of the body.

The blisters therefore only affect one area of the body and do not cross the midline

The rash and pain usually subside within 3 to 5 weeks. The most common chronic complication of herpes zoster is postherpetic neuralgia.

serious effects including partial facial paralysis (usually temporary), ear damage, or encephalitis may occur.

Shingles on the upper half of the face (the first branch of the trigeminal nerve) may result in eye damage

Treatment

Aciclovir (an antiviral drug) inhibits replication of the viral DNA, and is used both as prophylaxis (e.g. in patients with AIDS) and as therapy for herpes zoster.

Steroids are often given in severe cases

A vaccine called live attenuated Oka/Merck VZV that has been proven successful in preventing it

Influenza

Influenza, commonly known as the flu or the grippe, is a contagious disease of the upper airways and the lungs, caused by an RNA virus

Symptoms

The virus attacks the respiratory tract, is transmitted from person to person by saliva droplets expelled by coughing, and causes the following symptoms:

Fever
Headache
Fatigue/Sore joints (can be extreme)
Dry cough
Sore throat
Nasal congestion
Sneezing
Irritated eyes
Body aches
Extreme coldness

Treatment

get plenty of rest, drink a lot of liquids

acetaminophen to relieve the fever and muscle aches

Children and teenagers with flu symptoms (particularly fever) should avoid taking aspirin as taking aspirin in the presence of influenza infection (especially influenza type B) can lead to Reye syndrome, a rare but potentially fatal disease of the liver

Mumps

Mumps or epidemic parotitis is a viral disease of humans.

Caused by a paramyxovirus, and is spread from person to person by saliva droplets or direct contact

Symptoms

The more common symptoms of mumps are:

Swelling of the parotid gland (or parotitis) in >90% of patients.

Fever
Headache
Sore throat
Orchitis

A physical examination confirms the presence of the swollen glands

If  there is uncertainty about the diagnosis, serology or a saliva test for the virus may be carried out.

Rubella

caused by the Rubella virus

Symptoms

swollen glands or lymph nodes (may persist for up to a week)

fever (rarely rises above 38 degrees Celsius [100.4 degrees Fahrenheit])

rash (Appears on the face and then spreads to the trunk and limbs. It appears as pink dots under the skin. It appears on the first or third day of the illness but it disappears after a few days with no staining or peeling of the skin)

Forchheimer's sign occurs in 20% of cases, and is characterized by small, red papules on the area of the soft palate flaking, dry skin

inflammation of the eyes

nasal congestion

joint pain and swelling

pain in the testicles

loss of appetite

headache

nerves become weak or numb (very rare)

rubella can cause congenital rubella syndrome in the fetus of an infected pregnant woman.

Treatment

No specific treatment

MMR Vaccine is effective prevention

Poliomyelitis

infantile paralysis, is a viral paralytic disease.

The causative agent, a virus called poliovirus (PV), enters the body orally, infecting the intestinal wall.

It may proceed to the blood stream and into the central nervous system causing muscle weakness and often paralysis

Meningitis

Meningitis is inflammation of the membranes (meninges) covering the brain and the spinal cord.

Symptms

The classical symptoms of meningitis are headache, neck stiffness and photophobia (intolerance of bright light); the trio is called meningism.

 Fever and chills are often present, along with myalgia.

An altered state of consciousness or other neurological deficits may be present depending on the severity of the disease.

In meningococcal meningitis or septicaemia, a petechial rash may appear.

 A lumbar puncture to obtain cerebrospinal fluid (CSF) is usually indicated to determine the cause and direct appropriate treatment.

Convulsions and hydrocephalus are known complications of meningitis.

Diagnosis

examination of the cerebrospinal fluid

In patients with focal neurological deficits or signs of increased intracranial pressure, a CT scan of the head

Treatment

a broad spectrum intravenous antibiotic should be started immediately , often a third generation cephalosporin

Corticosteroids to relieve brain pressure and swelling and to prevent hearing loss that is common in patients with Haemophilus influenza meningitis

anticonvulsants such as dilantin or phenytoin to prevent seizures and corticosteroids to reduce brain inflammation

Vaccinations against Haemophilus influenzae (Hib) have decreased early childhood meningitis.