Herpes simplex virus

HSV- Types HSV 1 and HSV 2, Mode of action, Replication, Symptoms,Treatment

1. Presentation by: A.Abinaya Kalyani , III B.Sc Microbiology, HERPES SIMPLEX VIRUS

2. Herpes Simplex Viruses: The herpes simplex virus, also known as HSV, is an infection that causes herpes. Herpes can appear in various parts of the body, most commonly on the genitals or mouth . The term “herpes” means “to creep” (easily spreading nature). There are two types of the herpes simplex virus. HSV-1: Also known as oral herpes, this type can cause cold sores and fever blisters around the mouth and on the face, This can spread by contact with infected saliva. HSV-2: This type is generally responsible for genital herpes outbreaks. This type can transmitted Sexually.

3. Herpes viruses are large enveloped DNA Viruses. Virion is spherical , 150-200nm in diameter. It has a icosahedral capsid . Its genome is linear double stranded DNA, 124-235kbp More than 35 proteins are present in the virion . Replication occurs in the nucleus of the host cell. Genome is large enough to code for atleast 100 proteins. Structure of virus:

4. HSV 1: HSV-1 is the virus that causes cold sores or fever blisters, it may start with a tingling, itching, or burning on the skin, usually on the lips Tiny blisters show up and quickly break open, causing a painful sore which eventually scabs over. It’s most common to have outbreaks 2-3 times a year. A sore can take a week or two to heal without medication. Herpes is contagious , but it's possible for one person in a family to have it, while the others don't. Herpes is spread through direct skin to skin contact like kissing. 

5. HSV 2: Genital herpes is a common sexually transmitted infection caused by the herpes simplex virus. There's no cure for genital herpes, but medications can ease symptoms and reduce the risk of infecting others.  The symptoms may begin about 2 to 12 days after exposure to the virus. Women are more likely to have genital herpes than are men. The virus is sexually transmitted more easily from men to women than it is from women to men. Babies born to infected mothers can be exposed to the virus during the birthing process. This may result in brain damage, blindness or death for the newborn. Vaginal area Penis External genitals Scrotum Cervix Symptoms

6. Replication process of HSV

7. Clinical Manifestation: The symptoms can be quite severe and may include: blisters and ulceration on external genitalia, in the vagina, or on the cervix vaginal discharge pain and itching tender, enlarged lymph nodes pain when urinating high temperature (fever) malaise (feeling unwell) cold sores around the mouth red blisters on the skin In most cases, the ulcers will heal, and the individual will not have any lasting scars.

8. Infection of other Organs: Herpetic Whitlow Herpes Gladiatorum Eczema Herpeticum

9. Pathogenesis: Primary Infection:   Man is the only natural host to HSV, the virus is spread by contact, the usual site for the implantation is skin or mucous membrane.  HSV undergoes replication in the parabasal and intermediate epithelial cells, which lyse and invoke inflammatory response. The incubation period of primary genital herpes is 3-7 days. Constitutional symptoms include fever, headache, malaise, and myalgia (prominent in the first 3-4 days). Local symptoms include pain, itching, dysuria , vaginal and urethral discharge, and tender lymphadenopathy .

10. Pathogenesis: Reactivation:  It is well known that many triggers can provoke a recurrence. These include; Stress - physical or psychological. Pneumococcal infection. Meningococcal infection.  Fever Irradiation including sunlight. Menstruation Others.

11. Laboratory Diagnosis: Specimen collection: Vesicular and hepatic lesions of skin, cornea or brain, throat washings, CSF and Stool. Light Microscopy:  Cells from the base of the lesion, or wiped from a mucous surface, or biopsy material, may reveal intranuclear inclusions ( Lipschutz inclusion bodies). Infected cells may show ballooning and fusion.

12. Isolation of Virus: The specimen are transported through viral transport medium and inoculated into tissue culture. HSV has a wide host range, so many cell culture systems are susceptible. The appearance of typical cytopatheic effects in cell culture in 2-3 days suggests the presence of HSV. Serology: Several methods have been developed for rapid diagnosis. Antibodies appear in 4-7 days after infection. Neutralization test, CF, ELISA, RIA and Immunofluorescence can quantitate antibodies. Laboratory Diagnosis:

13. Epidemiology: Herpes Simplex viruses are worldwide in distribution. No animal reservoirs are involved in human infection transmission. Transmission is by infected secretions. Prevention: Currently there is no effective therapy for the prevention of HSV infection. Avoidance of direct contact with lesion or infected secretions is the primary means of prophylaxis. Vaccination for Herpes would be the ideal preventive measure.

14. Treatment: There is no cure for herpes. But medicines can help. Medicines such as acyclovir and valaciclovir fight the herpes virus. They can speed up healing and lessen the pain of herpes for many people. They can be used to treat a primary outbreak or a recurrent one. If the medicines are being used to treat a repeat outbreak, they should be started as soon as you feel any tingling, burning, or itching. They can also be taken every day to prevent recurrences. Most of the drugs used for the treatment of HSV, inhibit the DNA synthesis. Vidarabine triphosphate inhibits DNA polymerase.

15. thank you..! For your Attention..!