Varicella-Zoster virus (VZV)

 Varicella-Zoster virus (VZV) is a member of the herpesvirus family and causes two distinct diseases: Varicella (chickenpox) occurs during primary infection and herpes zoster (shingles) during reactivation. After initial infection, the virus remains dormant in the ganglia and may reactivate later in life, especially if the immune system is weakened.

 Diseases caused by VZV  :

 1. Chickenpox (Varicella): - 

• A highly contagious disease characterized by itchy rash, fever, and malaise.
• Most common in children, but adults may also develop the disease, which tends to be severe.
• Transmitted by respiratory droplets or direct contact with lesions.

 2. Herpes Zoster: -

• Caused by reactivation of dormant VZV. - 
• It is characterized by a painful localized rash along a single neurocutaneous segment.
• Risk increases with age or immunosuppression.

  sypmtoms :

   Chickenpox: 

•  Fever, fatigue, malaise.
•  Rash :

•     Begins as red spots and progresses to fluid-filled blisters (vesicles) and scabs.
•      Lesions often form “papules” with new lesions forming as the old lesions heal. 
•     Usually begins on the trunk and spreads to the face, arms, and legs.

 Shingles: -

•  Pain, burning, or tingling (prodrome) in a specific area.
•  Rash: -

        Red spots that develop into fluid-filled blisters. - Localized to one side of the body along the nerve pathways (dermatome).

 Other symptoms: - 

•       Headache, fever, malaise. 
•       Persistent nerve pain (postherpetic neuralgia) may follow the rash.

Transmission:

  Chickenpox : -

 

•     Highly contagious from 1 to 2 days before the rash appears until all      lesions crust over. 
•    Transmitted by respiratory droplets or direct contact with vesicle          fluid.

  Shingles: -

•  Not as contagious as chickenpox. 
• Direct contact with vesicular fluid from shingles can cause chickenpox in persons who have never had chickenpox or have not been vaccinated.

 Complications

1. Chickenpox: - 

•  Bacterial skin infection.
•  Pneumonia (especially in adults). 
•  Encephalitis or cerebellar ataxia.
•  If infected during pregnancy, congenital varicella syndrome.

 2. Herpes zoster: - 

• Postherpetic neuralgia (PHN): 
• nerve pain that persists after the rash has disappeared. 
• Sight loss (if ocular nerves are involved).
• Secondary bacterial infections. 
• Neurologic complications such as meningitis or myelitis. 

Diagnosis

•   Clinical manifestations:

            typical rash pattern and distribution. 

 Laboratory tests: -

•  PCR: detects VZV DNA (highly sensitive).
•  Direct Fluorescent Antibody (DFA): Identifies virus in lesion samples.
•  Serology: Detect VZV antibodies to confirm the presence or absence of exposure.

 Treatment 

1. Chickenpox -

• supportive care

• Antihistamines for itching.
• Acetaminophen for fever (avoid aspirin to prevent Reye's syndrome). 
• Antiviral therapy (e.g., aciclovir) in severe cases, adults, and immunocompromised individuals;

 2. Herpes zoster: -

• Antivirals (e.g., aciclovir, valacyclovir, or famciclovir) to reduce    severity  and duration of illness.
• Pain management: 

• Over-the-counter or prescription analgesics for severe pain.
• Topical lidocaine or capsaicin cream for localized pain.
• Corticosteroids (in some cases) to reduce inflammation.

 vaccinations:

 1. Chickenpox Vaccine(Varicella vaccine): 

•   A live attenuated vaccine given twice in childhood.
•   Highly effective in preventing or reducing the severity of chickenpox

.2. Herpes zoster vaccine 

•  Shingrix (genetically modified vaccine): - Recommended for adults over 50 years of age or those with compromised immunity. 
•  Significantly reduces the risk of herpes zoster and postherpetic neuralgia. 

 Prevention:

• Vaccination is the most effective way to prevent VZV-related diseases.
• Avoid contact with infected persons, especially if immunocompromised or unvaccinated. - 
• Proper hygiene and covering lesions can help reduce the spread of the virus. 

 Prognosis:

• Chickenpox: generally mild in healthy children, but may cause complications in adults and immunocompromised patients.
• Herpes zoster: pain and rash usually resolve in 2-4 weeks, but postherpetic neuralgia may persist, especially in the elderly. 

With timely treatment and vaccination, VZV-related outcomes are markedly improved and complications are reduced.

Herpes

 Herpes simplex virus (HSV) is a common viral infection caused by two types of herpes viruses: HSV-1 and HSV-2. These viruses are known to cause painful blisters and sores, often referred to as “cold sores” or “fever blisters” (in HSV-1) or genital herpes (usually associated with HSV-2) because the HSV virus is dormant in the body and reactivates periodically, HSV infection can last a lifetime.

Types of herpes simplex virus: 

HSV-1 (herpes simplex virus type 1): causes herpes labialis, which causes sores primarily around the mouth and face.

HSV-2 (herpes simplex virus type 2): primarily causes genital herpes and causes sores around the genitals or anus. 

symptoms of HSV:

primary infection:

 

    Oral Herpes(HSV-1) :

•           ulcers around the lips, mouth, or face. 
•           Fever, swollen lymph nodes, and fatigue.
•           Tingling and itching occur before the sores form.

 Genital herpes (HSV-2): 

•     painful blisters or ulcers on the genital or anal area. 
•     Pain and burning sensation when urinating. 
•    Flu-like symptoms including fever, body aches, and swollen lymph nodes.

 Asymptomatic infection:

 

• Most HSV-infected individuals do not show any noticeable symptoms, but they can transmit the virus.

 

Transmission:

HSV is highly contagious and is spread by direct contact with infected skin, mucous membranes, or body fluids. Common routes of transmission include:

•  HSV-1: saliva, kissing, sharing dishes, oral and genital contact.
•  HSV-2: sexual contact, including vaginal, anal or oral intercourse.
•  HSV can be transmitted without visible sores (asymptomatic shedding)
• HSV-3: contact with skin, mucous membranes, or body fluids.

 Diagnosis:

 Physical examination: based on characteristic blisters or sores. 

 Laboratory studies:

•  detection of HSV DNA by viral culture or polymerase chain reaction (PCR). 
•  Blood testsdetection of HSV-specific antibodies (IgG/IgM) to distinguish HSV-1 from HSV-2.

Tzanck test:

•  microscopic examination of cells in the sores. 

Treatment of HSV : 

There is no cure for HSV, but antiviral medications can reduce symptoms, decrease the frequency of outbreaks, and reduce the Reduce the risk of infection. Reduce risk of infection 

1.Antiviral medications: 

• acyclovir, valacyclovir, and famciclovir are commonly prescribed.
•  For primary infection: 7-10 days of antiviral treatment.
•  For recurrent infections: shorter duration (1-5 days). 
• For frequent infections: daily antiviral suppressive therapy.

2. Symptom relief: 

• over-the-counter analgesics such as ibuprofen or acetaminophen.
•  Topical lidocaine or numbing cream to reduce discomfort.
•  Compresses to cool the affected area. 

Complications:

• Herpes keratitis: eye infection that can lead to blindness. 
• Herpes neonatorum: Aggressive infection in a pregnant woman during childbirth can cause severe infection in the newborn.
• Herpetic eczema: HSV commonly infects eczematous and immunocompromised individuals.
• Psychological effects: anxiety and distress due to stigma, recurrence of symptoms.

 Prevention: 

• Avoid close contact with infected persons during outbreaks.

Use condoms or dental dams during intercourse.

• if infected with HSV, receive antiviral treatment to reduce risk of transmission.
• pregnant women infected with HSV should notify their health care providers to manage the risk of neonatal herpes.

 Prognosis : 

With appropriate treatment, most HSV patients can lead a normal life. Antiviral medications and lifestyle modifications can significantly reduce the frequency and severity of illness and the risk of infection.