All about Herpes Simplex

A B C of herpes  ::Herpes simplex virus

Genital  herpes simplex  virus  infection is one of the most common sexually  transmitted diseases according to the Centers  for Disease Control   and Prevention  . an  estimated  50  million adolescents and adults are currently  affected. In 2012   there were 228,000 initial   office visits for genital herpes . although   most  women are unaware of their infection approximately one in six  has serological   evidence  for HSV-2 infection. This incidence  is  as high as one in two for non Hispanic black  pregnant women  . as most case  of HSV  are transmitted by persons who are asymptomatic   or unaware of their  disease  herpes infections have become  a major   public health concern. It is  estimated  that 0.5  to 2 percent of pregnant  women   acquire  HSV-1 or 2 during pregnancy .

 Pathogenesis and Transmission

Two  types of HSV  have been distinguished based on immunological   and clinical    differences. Type 1 is responsible for most   nongenital  infections. However  more than half  of new cases    of genital herpes in adolescents and young adults  are caused by HSV-1 infection. This is thought to be due to an increase in oral genital sexual practices .type 2 HSV  is recovered  almost  exclusively   from the genital tract and is usually transmitted  by sexual  contact. Most  recurrences –greater than 90  percent-  are secondary  to HSV -2 . There is a large amount of DNA sequence homology between the two viruses and  prior infection with one type  attenuates a primary  infection with  the other type.

Neonatal  transmission is by  three routes : intrauterine  in 5 percent,  peripartum in 85   percent or  postnatal in 10 percent  , The fetus   becomes infected  by virus   shed from the  cervix or lower genital tract . It  either invades the uterus following  membrane   rupture  or is transmitted by contact with the fetus  at delivery . The overall  transmitted by  contact with the fetus  at delivery . The overall  transmission  rate is 1 in 3200  to 1 in 30,000 births depending  on the population  studied . Neonatal    herpes in caused by both  HSV -1  and HSV -2   although HSV-2  infection  predominates . Most  infected  infants are  born to mothers  with no reported  history  of HSV  infection

The risk of neonatal  infection  correlates  with the presence of HSV  in the genital   tract the HSV  type invasive   obstetrical procedures  and stage of  women who acquire   genital HSV  near the time of delivery   have a 30  to 50 percent risk of infection. This is  attributed to higher   viral loads and the lack of transplacental   protective antibodies   . women with  recurrent  HSV  have less than a 1percent  risk of neonatal  infection.