The Varicella-zoster virus (VZV) is a highly contagious virus that causes two distinct diseases: varicella, commonly known as chickenpox, and herpes zoster, or shingles. While these illnesses have been recognized for many years, the need for accurate and efficient diagnostic tools remains crucial. This blog aims to comprehensively understand the Varicella-zoster virus, its associated diseases, and the emerging role of rapid test kits in diagnosing VZV infections.
What is Varicella-Zoster Virus (VZV)?
Varicella-Zoster Virus (VZV) is a double-stranded DNA virus that belongs herpesviradae family as an alpha herpes virus. Varicella-Zoster Virus is a highly contagious infection with VZV that causes two distinct diseases, chickenpox (varicella) and shingles (herpes zoster) [1]. VZV only naturally infects humans with no animal reservoir; its main targets are T lymphocytes, epithelial cells, and ganglia [2].
What is Chickenpox?
Chickenpox is a worldwide, airborne disease that is spread by coughing, sneezing, and contact with skin lesions [3]. Chickenpox or varicella is a common childhood disease characterized by a skin rash that forms small, itchy blisters which scab over. The disease typically starts on the chest, back, and face and then spreads. It appears with fever, pharyngitis, fatigue, and headaches, usually lasting five to seven days. Symptoms begin 10 to 21 days after exposure. Although chickenpox is more common in children than adults, the disease is more severe in adults. Also, it can lead to complications in pregnant women, newborns, and people with weak immune systems.
Symptoms of Chickenpox can be listed as follows:
- Rash
- Fever
- Headache
- Being Unwell
- Cough
- Runny Nose
- Loss of Appetite
The treatment of chickenpox typically involves managing the symptoms and promoting comfort while the infection runs its course. But it is possible to avoid chickenpox before infection by vaccination, especially vaccination of children is the most effective method to prevent the disease. Here are commonly recommended treatments for chickenpox; home care, antihistamines, oatmeal baths, cool compresses, hydration, and sometimes antiviral medications prescribed by healthcare professionals.
What is Shingles?
Shingles, are also known as herpes zoster, is a viral infection caused by the varicella-zoster virus (VZV) – the same virus that causes chickenpox [4]. After a person recovers from chickenpox, the virus can remain dormant in the nervous system. Later in life, usually due to a weakened immune system or other factors, the virus can reactivate and cause shingles.
Shingles typically manifests as a painful rash that usually appears on one side of the body, often in a stripe or band-like pattern [4]. The rash is characterized by fluid-filled blisters that eventually crust over. Along with the rash, individuals may experience symptoms such as tingling, itching, and burning sensations in the affected area. Other symptoms can include fever, headache, and fatigue, likely chickenpox.
The main complication of shingles is postherpetic neuralgia (PHN), which is persistent nerve pain that can last for weeks, months, or even years after the rash has healed [5]. This condition is more common in older people.
Treatment for shingles often involves antiviral medications to help shorten the duration of the infection and reduce the severity of symptoms. Pain relievers, anti-inflammatory drugs, and topical creams or ointments can also be prescribed to alleviate discomfort. Vaccination against shingles is available and recommended for individuals aged 50 and older to prevent or reduce the risk of developing the infection.
What is the Varicella-zoster virus (VZV) Rapid Test Kit?
There was no widely available rapid test specifically designed for detecting the Varicella-zoster virus (VZV). The diagnosis of varicella or herpes zoster is typically based on clinical symptoms and history, and laboratory testing is not commonly required.
In most cases, a healthcare professional can diagnose varicella or herpes zoster by examining the characteristic rash and considering the patient’s symptoms. However, laboratory tests may be conducted when the diagnosis is unclear or confirmation is needed.
Laboratory tests for VZV infection can include:
Viral Culture: A fluid sample from the blisters or lesions may be collected and tested to isolate and grow the virus in the laboratory.
Polymerase Chain Reaction (PCR): This molecular technique detects the virus’s genetic material (DNA) in a sample, such as fluid from the blisters or cerebrospinal fluid.
These tests are typically performed in specialized laboratories and may take some time to yield results.
It’s important to note that the availability and advancements in testing methods may have changed since my last update. Therefore, it is recommended to consult with healthcare professionals or reference current medical literature for the most up-to-date information on VZV testing options, including any potential development of rapid test kits.
How to Diagnose Varicella-Zoster Virus?
The diagnosis of Varicella-zoster virus (VZV) infections, such as varicella (chickenpox) and herpes zoster (shingles), is typically based on clinical presentation and medical history. In most cases, laboratory testing is not necessary. However, healthcare professionals may employ specific diagnostic methods when the diagnosis is unclear or confirmation is needed. Here are the common approaches for diagnosing VZV infections:
Clinical Examination: A healthcare professional will evaluate the characteristic signs and symptoms of varicella or herpes zoster. This includes assessing the appearance of the rash, its distribution, and associated symptoms such as fever, itching, and pain.
Patient History: Gathering information about the patient’s medical history, including any recent exposure to individuals with varicella or shingles, previous episodes of chickenpox or shingles, and vaccination status, can be helpful in confirming the diagnosis.
Polymerase Chain Reaction (PCR): PCR testing is a molecular diagnostic method that detects the genetic material (DNA) of the virus. It is most commonly used in cases where confirmation of VZV infection is required, especially in atypical or severe cases. PCR can be performed on samples obtained from fluid collected from skin lesions or, in the case of herpes zoster, from cerebrospinal fluid if there are suspected complications involving the nervous system.
Viral Culture: Viral culture may be employed in certain instances, particularly for severe or unusual cases. A sample from the skin lesions or other affected areas is collected and sent to a laboratory for analysis. The virus is grown and isolated in the laboratory, confirming the presence of VZV.
It’s important to note that these diagnostic methods may vary depending on the healthcare setting and the specific situation. In most cases, clinical examination and patient history are sufficient for diagnosing varicella or shingles. Laboratory tests are typically reserved for confirming the diagnosis in atypical cases, immunocompromised individuals, pregnant women, or cases with potential complications.
Consulting with a healthcare professional is crucial for diagnosing and appropriately managing VZV infections.
REFERENCES
[1] Otani N, Shima M, Yamamoto T, Okuno T. Effect of Routine Varicella Immunization on the Epidemiology and Immunogenicity of Varicella and Shingles. Viruses. 2022 Mar 12. 14 (3):[QxMD MEDLINE Link].
[2] Gershon AA, Breuer J, Cohen JI, Cohrs RJ, Gershon MD, Gilden D, Grose C, Hambleton S, Kennedy PG, Oxman MN, Seward JF, Yamanishi K. Varicella zoster virus infection. Nat Rev Dis Primers. 2015 Jul 2;1:15016. doi: 10.1038/nrdp.2015.16. PMID: 27188665; PMCID: PMC5381807.
[3] Ayoade F, Kumar S. Varicella-Zoster Virus (Chickenpox) [Updated 2022 Oct 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448191/
[4] AskMayoExpert. Herpes zoster (shingles). Mayo Clinic; 2022.
[5] Shingles (herpes zoster): Clinical overview. Centers for Disease Control and Prevention. https://www.cdc.gov/shingles/hcp/clinical-overview.html. Accessed June 15, 2023.
[Figure 1] Symptoms of chickenpox. A girl with chickenpox, 1146078332.
[Figure 2] Jewell, T. (2023) Everything you need to know about shingles lesions, Healthline. Available at: https://www.healthline.com/health/shingles-lesions. Accessed: June 13, 2023.
[Figure 3] Gershon, A. A., Breuer, J., Cohen, J. I., Cohrs, R. J., Gershon, M. D., Gilden, D., … & Yamanishi, K. (2015). Varicella zoster virus infection. Nature reviews Disease primers, 1(1), 1-18.
