TRANSPLACENTAL INFECTION BY HERPES SIMPLEX VIRUS

Implications of TORCH Diseases in Retinal Development-Special Focus on Congenital Toxoplasmosis

There are certain critical periods during pregnancy when the fetus is at high risk for exposure to teratogens. Some microorganisms, including Toxoplasma gondii, are known to exhibit teratogenic effects, interfering with fetal development and causing irreversible disturbances. T. gondii is an obligate intracellular parasite and the etiological agent of Toxoplasmosis, a zoonosis that affects one third of the world's population. Although congenital infection can cause severe fetal damage, the injury extension depends on the gestational period of infection, among other factors, like parasite genotype and host immunity. This parasite invades the Central Nervous System (CNS), forming tissue cysts, and can interfere with neurodevelopment, leading to frequent neurological abnormalities associated with T. gondii infection. Therefore, T. gondii is included in the TORCH complex of infectious diseases that may lead to neurological malformations (Toxoplasmosis, Others, Rubella, Cytomegalovirus, and Herpes). The retina is part of CNS, as it is derived from the diencephalon. Except for astrocytes and microglia, retinal cells originate from multipotent neural progenitors. After cell cycle exit, cells migrate to specific layers, undergo morphological and neurochemical differentiation, form synapses and establish their circuits. The retina is organized in nuclear layers intercalated by plexus, responsible for translating and preprocessing light stimuli and for sending this information to the brain visual nuclei for image perception. Ocular toxoplasmosis (OT) is a very debilitating condition and may present high severity in areas in which virulent strains are found. However, little is known about the effect of congenital infection on the biology of retinal progenitors/ immature cells and how this infection may affect the development of this tissue. In this context, this study reviews the effects that congenital infections may cause to the developing retina and the cellular and molecular aspects of these diseases, with special focus on congenital OT.

A report of three cases and review of intrauterine herpes simplex virus infection

BACKGROUND

intrauterine herpes simplex virus (HSV) infection often is omitted from descriptions of neonatal HSV disease. Previous characterizations of intrauterine HSV infection limit manifestations to the triad of cutaneous, central nervous system (CNS), and ophthalmologic findings. We report 3 cases of intrauterine HSV infection and provide a contemporary literature review of this disease.

METHODS

cases published between 1963 and January 2009 were identified. Selected cases fit the clinical description of intrauterine HSV infection, had manifestations present at birth, and had virologic confirmation of infection.

RESULTS

this review yielded 64 cases, 3 of which were our own, of intrauterine HSV infection. Less than one-third fit the typical triad. Of the patients with cutaneous findings at birth, 24 (44%) had manifestations other than vesicles or bullae. Confirmation of HSV infection by culture of cutaneous lesions present at birth was delayed beyond 72 hours after birth in 15 patients and occurred at a median of 10 days of age. Nine of these patients had lesions at birth that were neither vesicles nor bullae, and 14 cases were confirmed by culture of new vesicles.

CONCLUSIONS

more than two-thirds of reported cases do not present with the typical triad. Cutaneous findings are not limited to vesicles or bullae. A high index of suspicion and recognition of varied cutaneous manifestations is necessary to diagnose infants with intrauterine HSV infection.

Hematogenous vertical transmission of herpes simplex virus type 1 in mice

Herpes simplex virus type 1 (HSV-1) is a neurotropic virus that causes severe disease and death in newborn humans but, to date, it remains unclear how neonatal infection occurs. We show here that the vertical transmission of HSV-1 in mice is mainly hematogenous and involves the colonization of the neonate central nervous system (CNS). HSV-1 DNA was mainly detected in the blood and CNS of the offspring born to latently infected mothers; no significant differences were seen between the viral DNA concentrations in the blood of these mothers and their female progeny (either neonate or adult). The administration of acyclovir during gestation reduced or eliminated both the maternal and the neonatal viral DNA in the blood. Embryo transfer was performed to ensure (as far as possible) that only vertical hematogenous infection took place. Immunohistochemical analysis detected viral proteins in the encephalon of the offspring. Immunofluorescence studies provided immunoreactive evidence of HSV-1 proteins in the neurons of the hippocampus and showed that these viruses can molecularly reactivate after hyperthermia. Neonatal HSV-1 infection therefore appears to be mainly caused by hematogenous vertical transmission, and the viruses that colonize the offspring CNS are capable of molecular reactivation after a period of latency.

Acycloguanosine therapy of the localized form of herpes simplex virus infection in a low-birth-weight infant

It is known that the localized form of herpes simplex virus (HSV) infection does not always show a good prognosis. A preterm infant who evidenced skin and tongue lesions, caused by HSV type 1, was treated by acycloguanosine. The result was satisfactory without any complications. Therefore, a localized form of HSV infection of the newborn infant, even though the patient has a low-birth-weight, should be treated by the drug immediately after the observation of the positive HSV culture.

Herpes genitalis

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