Viral shedding

Both amantadiae and rknantadiae have been found to reduce the duration of influenza A-iaduced fever and malaise, and to lessen viral shedding. Prophylactic treatment has been recommended for high risk patients (95). It has been suggested that, ia the presence of amantadine, the influenza vims attaches normally to cells, but once iaside the ceU the vims fails to initiate repHcation. Thus amantadine appears to inhibit the initiation of transcription at an early stage between uncoating and viral-specific RNA synthesis (96). 

Hepatitis E is a non-enveloped single-stranded messenger RNA virus of unclassified genus.18 The HEV is similar to HAV in that the virus is harvested in contaminated feces, thus infecting people via the fecal-oral route. High HEV levels in the bile often prompt viral shedding in the feces. The severity of hepatic damage is dependent on the HEV strain Mex 14, Sar 55, or the US 2 strain.19 No cases of chronic hepatitis E have yet been documented. 

The first episode is a systemic illness associated with the vesicular lesions, may last up to 21 days, usually has an uncomplicated course of infection, and in severe cases may require hospitalization. Several agents have been found to be effective during this period (Table 77-3).28,29 At the cited dosages, these agents have had excellent outcomes with regard to lesion healing time, viral shedding, and loss of pain. Common adverse effects are nausea, headache, and diarrhea. 

Topical aciclovir has limited effectivity in the treatment of recurrent herpes genitalis or herpes febrilis infections in non-immunocompromised patients, although topical aciclovir may cause some reduction in the duration of viral shedding. Topical aciclovir has no role in the treatment of herpes zoster. 

Oral acyclovir is useful in the treatment of HSV-1 and HSV-2 infections, such as genital herpes, herpes encephalitis, herpes keratitis, herpes labialis, and neonatal herpes. In initial episodes of genital herpes, oral acyclovir has been found to reduce viral shedding, increase the speed of healing of lesions, and decrease the duration of pain and new lesion formation. Acyclovir appears to be less effective in the treatment of recurrent herpes genitalis but may be used for the long-term suppression of recurrent HSV. 

Amantadine and rimantadine are used for the treatment of diseases caused by influenza A strains. When these agents are administered within 48 hours of the onset of symptoms, they reduce the duration of fever and systemic complaints by 1 to 2 days and may decrease the duration of viral shedding. Evidence is insufficient to suggest that treatment with these drugs will prevent... 

Oral acyclovir has multiple uses (Table 49-1). In primary genital herpes, oral acyclovir shortens by approximately 5 days the duration of symptoms, the time of viral shedding, and the time to resolution of lesions in recurrent genital herpes, the time course is shortened by 1-2 days. 

Topical acyclovir (Zovirax) is available as a 5% ointment for application to primary cutaneous herpes simplex infections and to limited mucocutaneous herpes simplex virus infections in immunocompromised patients. In primary infections, the use of topical acyclovir shortens the duration of viral shedding and may decrease healing time. In localized, limited mucocutaneous infections in immunocompromised patients, its use may be associated with a decrease in the duration of viral shedding. 

Topical penciclovir (Denavir) is available as a 1% cream for the treatment of recurrent orolabial herpes simplex virus infection in immunocompetent adults. Application of penciclovir within 1 hour after appearance of the first sign or symptom of a recurrence and repeat application every 2 hours while awake for 4 days shortens viral shedding and reduces time to healing by approximately 1 day. Adverse local reactions to acyclovir and penciclovir may include pruritus and mild pain with transient stinging or burning. 

The route of influenza transmission is person-to-person via inhalation of respiratory droplets, which can occur when an infected person coughs or sneezes. The incubation period for influenza ranges between 1 and 4 days, with an average incubation of 2 days. Adults are considered infectious from the day before their symptoms begin through the fifth day after the onset of illness, while children can be infectious for longer than 10 days after the onset of illness. Viral shedding can persist for weeks to months in severely immunocompromised people. 

A multicenter, randomized, double-blind clinical trial showed no significant difference in duration of viral shedding, duration of pain, or time to loss of all symptoms in immimocompetent adults with an initial episode of genital HSV treated with oral valacyclovir or oral acyclovir (Valaciclovir International Study Group). 

Optimal antiviral treatment is begun within 48 to 72 hours of the first skin eruption to reduce further ocular involvement and perhaps decrease the duration of associated pain it has not been proven to prevent PHN. This optimal time course, however, should not detract from the value of antiviral therapy begim late, which may still be beneficial when initiated 3 to 7 days after eruption. Oral antivirals effectively hasten resolution of signs and symptoms, reduce viral shedding and formation of new skin lesions, and decrease both the incidence and severity of ocular complications. Controversy remains as to the best choice of oral therapy. Acyclovir 800 mg five times a day for 7 to 14 days has been the standard. Alternatively, valacyclovir, a prodrug of acyclovir, is administered at 1,000 mg three times a day and is considerably less expensive than acyclovir. Famciclovir, a prodrug of penciclovir,... 

Romanowski EG, Pless P. Topical cyclosporine A inhibits subepitheUal immune infiltrates but also promotes viral shedding in experimental adenovirus models. Cornea 2005 24 86-91. 

Inadvertent inoculation, the most frequent complication of smallpox vaccination, refers to the transmission of the vaccinia virus from the inoculation site to another part of the recipient s body (autoinoculation) or to the bodies of close contacts (Fig. 2.8 see color plate 2.8). It can occur because live vaccinia virus is present at the inoculation site from about 4 days after inoculation until the crust separates from the skin. Maximum viral shedding occurs 4-14 days after inoculation. Inadvertent inoculation is responsible for approximately half of all complications for primary vaccination and revaccination. Because inadvertent inoculation frequently results from touching the vaccination site and transmitting the virus manually, the most common affected sites are the face, eyelid, nose, mouth, genitalia, and rectum. Most cases heal without any specific treatment. Inadvertent inoculation of the eye can lead to comeal scarring and subsequent vision loss. Occasionally, vaccinia immune globulin (VIG) is necessary to treat periocular lesions (26). 

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. ... 

Adenovirus is an icosahedral virus previously associated with respiratory, ocular, and genitourinary infections however, serotypes 40 and 41 have been identified as GI pathogens. The peak incidence is in children younger than 2 years of age, and infections occur year-round. Transmission is primarily person to person and fecal-oral, and viral shedding from the gut may occur for extended periods. The incubation time is 8 to 10 days. Diarrhea and vomiting often last 1 to 2 weeks. Low-grade fever and respiratory symptoms are also common. The diagnosis can be made by enzyme immunoassay that identifies serotypes. 

Compared to primary infections, recurrent infections associated with (1) fewer lesions that are more localized, (2) shorter duration of active infection (lesions heal within 7 days), and (3) milder symptoms Severity of symptoms greater in females than in males Symptoms more severe and prolonged in the immunocompromised On average viral shedding lasts approximately 4 days Primary infections due to HSV-1 and HSV-2 virtually indistinguishable Recurrence rate is greater following primary infection with HSV-2 Recurrent infections with HSV-2 tend to be more severe... 

Reduces viral shedding in genital herpes acute neuritis in shingles but has no effect on postherpetic neuralgia. 

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. 

In immunocompromised patients with herpes zoster, intravenous acyclovir (500 mg/rrP every 8 hours for 7 days) reduces viral shedding, healing time, risks of cutaneous dissemination and visceral complications, and the length of hospitalization. In immunosuppressed children with varicella, intravenous acyclovir decreases healing time and the risk of visceral complications. 

In acyclovir-resistant mucocutaneous HSV infections, lower doses of foscamet (40 mgAg every 8 hours for 7 days or longer) are associated with cessation of viral shedding and complete healing of lesions in -75% of patients. Foscamet also appears to be effective in acyclovir-resist-ant VZV infections. Topical foscamet cream may be useful in chronic acyclovir-resistant infections in immunocompromised patients. 

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