HSV Flashcards
HSV 1 and HSV 2 cause which
HSV-1 is mainly transmitted by oral-to-oral contact, causing oral herpes (including symptoms known as cold sores), but it can also lead to genital herpes.
HSV-2 is a sexually transmitted infection that causes genital herpes.
Prevalence
An estimated 3.7 billion people under age 50 (67%) have HSV-1 infection globally.
An estimated 491 million people aged 15–49 (13%) worldwide have HSV-2 infection.
% of people who go on to develop symptoms
1 in 10 people
How is HSV related to HIV?
Infection with HSV-2 increases the risk of acquiring and transmitting HIV infection.
Can you check in the blood for HSV
Yes, you can check if someone is sero positive although this is rarely done other than in pregnancy. Blood tests that detect antibodies to HSV can distinguish between HSV-1 and HSV-2 but not the site of infection.
Which HSV is assoc with HSV encephalitis
HSV-1
What family is HSV in
The herpesviridae family - a large family of DNA virsus
Pathophysiology
Acquired at muscosal surfaces or breaks in the skin. Virus usually replicates in the epidermis then infects sensory or autonomic nerve endings and goes to the sensory ganglia. It then enters a latent state which allows the virus to evade the immune system causing life long infection. Periodic reactivation happens - some will have asymptomatic shedding of the virus, or can get symptoms - neuropathic ttingling / burning and ulceration.
When does transmission happen
It can be during asymptomatic or symptomatic reactivation. AQUISATION IS OFTEN ASYMPTOMATIC
Genital herpes signs and symptoms
Have high index of suspicion as presentation varies.
- Recurrent dysuria, tingling and burning without lesions
- Recurrent genital ulceration
WOMEN: genital pain, discharge, dysuria, ulcerative lesions. During primary infection when host lacks antibodies women tent o have a more severe px with fever, neuralgia and constipation.
MEN: milder primary course. May have vesicles on the shaft or glans with urethritis. May get proctitis with discharge, rectal pain, tenesmus, constipation, impotence, urinary retention.
General pattern of recurrence/ flare ups genital herpes
90% of people with primary HSV-2 have recurrent episodes within the first year, with recurrences decreasing over time
Herpes labialis signs and symptoms (oromucosal)
2-12d incubation
Primary HSV-1 sx: High fever and sore throat, painful ulcers can appear a few days later on the pharyngeal and oral mucosa. Generalised muscle pains with cervical lymphadenopathy.
MAJORITY HAVE ASYMPTOMATIC HSV-1 AQUISITION
How can herpes spread to baddd bad places
It can spread to the CNS - disseminated disease. HSV PCR on CSF should be sent if suspicious.
Risk factors for clinical disease and risk factors for seropositivity
RFs clin dis: HIV, immunosuppressive medications
RFs for seropositivity: high risk sexual behaviour, female, black, increasing age, lack of condom use
What testing can you do
- HSV PCR - highest sensitivity. [green viral swab]
- HSV culture
- Serology (glycoprotein G based specific serology - looking for positive antibody to hsv 1 or hsv 2) - this can be useful to assess the risk in asymp preg women for potential transmission to the infant at the time of delivery.
The presence of antibodies of the same type as the HSV isolated from genital swabs would confirm this episode to be a recurrence rather than a primary infection and elective caesarean section would not be indicated to prevent neonatal transmission. Neonatal herpes is a very rare but serious viral infection with a high morbidity and mortality.
