Viruses Herpetic infection

Several cases have been reported in which herpes simplex virus keratitis developed after initiation of latanoprost therapy. Although these cases are anecdotal, it is known that prostaglandins may play a crucial role in mediating inflammatory events that could incite herpetic infection. 

Herpes Simplex Virus Ophthalmia Neonatorum. HSY infection is an uncommon but important cause of neonatal infection and is associated with conjunctivitis in 5% to 10% of cases.The clinical manifestations are nonspecific and include conjimctival hyperemia, chemosis, periorbital edema, and mucous discharge. Corneal involvement is not uncommon and can include dendritic, geographic, or stromal keratitis. Herpetic ophthalmia neonatorum represents a primary herpetic infection. Central nervous system involvement, encephalitis, retinitis, optic neuritis, uveitis, choroiditis, and a fetal viremia can be serious sequelae of primary herpetic infections. 

Infants born of infected women may come in contact with the virus as they move down the birth canal, and this may result in a severe or even life-threatening neonatal infection. It is estimated that 1 in 350 infants is delivered vaginally during viral shedding, but the incidence of severe herpetic infection in the newborn is approximately 1 in 20,000. ... 

Clinical uses and toxicity The drug is used for prophylaxis and treatment of cytomegalovirus (CMV) infections (including CMV retinitis) and has activity against ganciclovir-resistant strains of this virus (Table 49-1). Foscarnet inhibits herpes DNA polymerase in acyclovir-resistant strains that are thymidine kinase-deficient and may suppress such resistant herpetic infections in patients with AIDS. Adverse effects include nephrotoxicity (30% incidence) with disturbances in electrolyte balance (especially hypocalcemia), genitourinary ulceration, and CNS effects (headache, hallucinations, seizures). 

The essential oil from Santolina insularis was also inhibited virus replication against HSV-1 and HSV-2 in vitro (Schnitzler et al. 2008). Its antiviral activity was principally due to direct virucidal effects (De Logu et al. 2000). Lemon balm oil, the essential oil of Melissa officinalis, is capable of exerting a direct antiviral effect on HSV-1 and HSV-2. Considering the lipophilic nature of essential oils, which enable it to penetrate the skin, and a high selectivity index, essential oils might be suitable for topical treatment of herpetic infections (Schnitzler et al. 2008). 

Herpetic conjunctivitis is usually a manifestation of primary HSV infection, which generally occurs in children between the ages of 6 months and 5 years. Most cases of herpetic ocular infection result from the nonvenereal form of the virus (HSV-1). Ocular infection with HSV-2 can occur in both newborns and adults. Infection may result from contact with the virus in the infected birth canal (herpetic neonatal conjunctivitis) or from autoinoculation after sexual contact with an infected partner. 

Oral acyclovir is effective in primary herpetic gingivostomatitis (600 mg/m four times daily for 10 days in children) but has only modest benefit in recurrent orolabial herpes. High-dose valacyclovir (2 g twice over one day) shortens the duration of recurrent orolabial herpes by 1 day. Topical acyclovir is modestly effective in recurrent labial and genital herpes simplex virus infections. Acyclovir prophylaxis (400 mg twice daily for one week) reduces the risk of recurrence by 73% in those with sun-induced recurrences of HSV infections. Acyclovir during the last month of pregnancy reduces the likelihood of viral shedding and frequency of cesarean section in women with primary or recurrent genital herpes. 

Studies on the incorporation of 2- C-labelled FEAD and FMAD into the DNA of mammalian cells showed very significant differences (Table IV). There was no detectable incorporation of FEAD radioactivity into the DNA of either L-1210 or Vero cel 1 lines, but substantial amounts of FMAD radioactivity were incorporated into the DNA of both cell lines. When HSV-1 infected Vero cells were exposed to C-labelled FEAD and FMAD, both nucleosides were incorporated into the DNA of these virus-infected cells. Dnder these conditions, FMAD incorporation into HSV-1 Infected Vero cells was 7-fold greater than that observed for FEAD. This difference in incorporation may be due to the greater affinity of FMAD for viral-encoded DNA pol3rmerase and is comparable to the magnitude of the difference of their anti-herpetic potencies in vitro (13). 

Theoretically, it may be possible to artificially increase the production of interferon by the action of an inducer. Synthetic double-stranded ribonucleotide polymers, in particular the double-helical complex of polyinosinic acid with poly-cytidylic acid RNA (poly IC) are used in this way These agents activate the synthesis of interferon. They increase the resistance to viruses of cells m culture, and promote recovery in rabbits suffering from herpetic eye infection. This type of activity is an important prospect in the field of antiviral therapy. 

---