![]() ![]() Brightfield microscopy involves imaging the transmitted light after passing through the specimen or the back-reflected light. ![]() Microscopy and Imagingīrightfield Microscopy: Historically, the most widely used HSV diagnostic tests were based on Brightfield microscopy. This is followed by detection using the various techniques discussed in the following sections. The virus is collected from lesions on skin or genitals by swabbing or scraping with a scalpel. Traditional diagnosis of HSV from lesions involves the direct detection of tissues or cells infected by the virus, viral proteins, whole virus, or genetic materials. The POC devices not only enable rapid and early HSV detection but are also capable of specifically differentiating the type of virus (HSV-1 vs. Several such kits are commercially available. The POC tests are usually based on microfluidic platforms and employ tests based on ELISA, immunofluorescence, PCR, and LAMP. These devices can be used for testing the patient at home, with no or minimal supervision, which is particularly useful in remote locations and resource-limited settings. We also focus on the different POC devices for herpes diagnosis that are portable, cost-effective, and can be easily operated without the need for expert handling. All these methods have their own advantages and drawbacks. Other methods include immunofluorescence assays, luminescence assays, and advanced microscopic techniques. Immunological assays include enzyme-linked immunosorbent assays (ELISA) and Western blot assays for effective detection of antigens (HSV glycoproteins) or antibodies specific to HSV glycoproteins, which have proven to be an excellent marker for HSV infection. This method is extremely sensitive and specific in detecting the virus. Molecular diagnosis of the virus can be achieved by nucleic acid amplification using polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP). This type of test required high-quality specimen collection, with proper handling and transportation of the specimen. Viral culture involves extracting the virus from the specimen, such as swab or needle aspiration, and culturing them for a few days, followed by microscopic analysis for determining HSV cytopathic effects (CPE). The conventional diagnostic strategies include viral culture, serological tests, and molecular techniques. Diagnosis of HSV typically involves detecting the whole virus or viral proteins, genetic materials, or HSV-specific antibodies in the blood. These include conventional methods as well as the different advanced technologies, particularly the POC. In this review, we focus on the different diagnostic technologies for herpes. Disease management studies have shown the importance of early testing and prior knowledge of patient history in guiding the proper course of treatment as well as providing counseling to patients and their significant others. Early diagnosis of the infection can help patients with proper disease management and also lower the risk of transmission. Attempts at developing vaccines against HSV have not yet been successful due to the complex host-pathogen interaction. To date, there is no cure for HSV infection, except for some antiviral drugs that can reduce the severity of the symptoms. The medical costs related to HSV have exceeded USD 500 million in the US alone in the past decade. Individuals who contract HSV may or may not show symptoms that increase the risk of spreading the disease unknowingly. Neonatal herpes in infants can occur upon exposure to HSV infection, mostly acquired from infected mothers, causing lifetime neurological defects and death. Immune deficient HIV patients are at higher risk, with the chance of developing drug-resistant HSV infection. Studies have shown that HSV can evade the immune system and mediate cell-to-cell propagation. Upon experiencing proper stimulus, it travels through the epithelial cells, causing characteristic symptoms like genital lesions, oral ulcers, and blisters. Upon entering the host body, the virus can stay dormant, generally located in the axons of the peripheral nervous system neuron. The virus is transmitted to a seronegative individual via abraded skin or mucosal surface. This staggering number of positive cases worldwide can be attributed to the highly infectious nature of this virus. It has been estimated that more than 500 million people globally, including 50 million in the US, have been infected with HSV. Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) are DNA-based viruses from the Herpesviridae family, responsible for causing herpes (genital or oral) and fulminate encephalitis in humans. ![]()
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