Recurrent herpes in the rabbit and man

Internal reference genes with the potential for normalizing quantitative PCR results for oral fluid specimens

In basic research, testing of oral fluid specimens by real-time quantitative polymerase chain reaction (qPCR) has been used to evaluate changes in gene expression levels following experimental treatments. In diagnostic medicine, qPCR has been used to detect DNA/RNA transcripts indicative of bacterial or viral infections. Normalization of qPCR using endogenous and exogenous reference genes is a well-established strategy for ensuring result comparability by controlling sample-to-sample variation introduced during sampling, storage, and qPCR testing. In this review, the majority of recent publications in human (n = 136) and veterinary (n = 179) medicine did not describe the use of internal reference genes in qPCRs for oral fluid specimens (52.9% animal studies; 57.0% human studies). However, the use of endogenous reference genes has not been fully explored or validated for oral fluid specimens. The lack of valid internal reference genes inherent to the oral fluid matrix will continue to hamper the reliability, reproducibility, and generalizability of oral fluid qPCR assays until this issue is addressed.

Herpes Simplex Virus Type 1 Shedding in Tears and Nasal and Oral Mucosa of Healthy Adults

BACKGROUND

Herpes simplex virus type 1 (HSV-1) is prevalent worldwide and causes mucocutaneous infections of the oral area. We aimed to define the frequency and anatomic distribution of HSV-1 reactivation in the facial area in persons with a history of oral herpes.

METHODS

Eight immunocompetent HSV-1 seropositive adults were evaluated for shedding of HSV-1 from 12 separate orofacial sites (8 from oral mucosa, 2 from nose, and 2 from conjunctiva) 5 days a week and from the oral cavity 7 days a week for approximately 5 consecutive weeks by a HSV DNA PCR assay. Symptoms and lesions were recorded by participants.

RESULTS

Herpes simplex virus type 1 was detected at least from 1 site on 77 (26.5%) of 291 days. The most frequent site of shedding was the oral mucosa, with widespread shedding throughout the oral cavity. Lesional shedding rate was 36.4% (4 of 11 days with lesions), and the asymptomatic rate was 27.1% (65 of 240 nonlesional days). In individual participants, the median rate of HSV shedding by HSV PCR was 19.7% of days (range, 11%-63%).

CONCLUSIONS

Reactivation of HSV-1 on the oral mucosa is common and usually asymptomatic. However, HSV-1 is rarely found in tears and nasal mucosa. Frequent oral shedding of HSV-1 may increase the risk for transmitting the virus to both oral and genital mucosa of sexual partners.

HSV-1 latent rabbits shed viral DNA into their saliva

Background

Rabbits latent with HSV-1 strain McKrae spontaneously shed infectious virus and viral DNA into their tears and develop recurrent herpetic-specific corneal lesions. The rabbit eye model has been used for many years to assess acute ocular infections and pathogenesis, antiviral efficacy, as well as latency, reactivation, and recurrent eye diseases. This study used real-time PCR to quantify HSV-1 DNA in the saliva and tears of rabbits latent with HSV-1 McKrae.

Methods

New Zealand white rabbits used were latent with HSV-1 strain McKrae and had no ocular or oral pathology. Scarified corneas were topically inoculated with HSV-1. Eye swabs and saliva were taken from post inoculation (PI) days 28 through 49 (22 consecutive days). Saliva samples were taken four times each day from each rabbit and the DNA extracted was pooled for each rabbit for each day; one swab was taken daily from each eye and DNA extracted. Real-time PCR was done on the purified DNA samples for quantification of HSV-1 DNA copy numbers. Data are presented as copy numbers for each individual sample, plus all the copy numbers designated as positive, for comparison between left eye (OS), right eye (OD), and saliva.

Results

The saliva and tears were taken from 9 rabbits and from 18 eyes and all tested positive at least once. Saliva was positive for HSV-1 DNA at 43.4% (86/198) and tears were positive at 28.0% (111/396). The saliva positives had 48 episodes and the tears had 75 episodes. The mean copy numbers ± the SEM for HSV-1 DNA in saliva were 3773 ± 2019 and 2294 ± 869 for tears (no statistical difference).

Conclusion

Rabbits latent with strain McKrae shed HSV-1 DNA into their saliva and tears. HSV-1 DNA shedding into the saliva was similar to humans. This is the first evidence that documents HSV-1 DNA in the saliva of latent rabbits.

Antiviral effects of blackberry extract against herpes simplex virus type 1

OBJECTIVE

The aim of this study was to evaluate antiviral properties of blackberry extract against herpes simplex virus type 1 (HSV-1) in vitro.

STUDY DESIGN

HSV-infected oral epithelial (OKF6) cells and cell-free virus suspensions were treated with blackberry extract (2.24-1,400 μg/mL), and virus yield and infectivity were quantified by direct plaque assay.

RESULTS

Blackberry extract ≥56 μg/mL inhibited HSV-1 replication in oral epithelial cells by >99% (P < .005). Concentrations ≥280 μg/mL were antiviral when the extract was added after virus adsorption and entry. Exposure of cell-free virus to ≥280 μg/mL blackberry extract for 15 minutes at room temperature was virucidal (P = .0002). The virucidal effects were not due to pH changes at concentrations up to 1,500 μg/mL.

CONCLUSIONS

Blackberry extract inhibited the early stages of HSV-1 replication and had potent virucidal activity. These properties suggest that this natural fruit extract could provide advantage as a topical prophylactic/therapeutic agent for HSV infections.

Ocular herpes simplex virus: how are latency, reactivation, recurrent disease and therapy interrelated?

Most humans are infected with herpes simplex virus (HSV) type 1 in early childhood and remain latently infected throughout life. While most individuals have mild or no symptoms, some will develop destructive HSV keratitis. Ocular infection with HSV-1 and its associated sequelae account for the majority of corneal blindness in industrialized nations. Neuronal latency in the peripheral ganglia is established when transcription of the viral genome is repressed (silenced) except for the latency-associated transcripts and microRNAs. The functions of latency-associated transcripts have been investigated since 1987. Roles have been suggested relating to reactivation, establishment of latency, neuronal protection, antiapoptosis, apoptosis, virulence and asymptomatic shedding. Here, we review HSV-1 latent infections, reactivation, recurrent disease and antiviral therapies for the ocular HSV diseases.

A double-blind placebo-controlled study to evaluate valacyclovir alone and with aspirin for asymptomatic HSV-1 DNA shedding in human tears and saliva

PURPOSE

To test the effect of valacyclovir alone and with aspirin on the asymptomatic shedding of HSV-1 DNA in tears and saliva of healthy individuals. METHOD. The subjects (n = 45) were randomized into three groups without regard to age, sex, or race. Group 1 (n = 14) received the placebo, group 2 (n = 15) received a dose of 500 mg valacyclovir once daily, and group 3 (n = 16) received a dose of 500 mg valacyclovir once daily and 350 mg aspirin twice daily for 30 days. Ocular and oral swabs were collected twice daily for 30 days. DNA was extracted from all swabs and HSV-1 DNA copy numbers were determined. Statistical analysis was performed to compare the DNA copy numbers of the three groups.

RESULTS

There was no significant difference in the HSV-1 DNA copy numbers in the tears or saliva among any of the three treatment groups. The mean copy numbers +/- SE of mean (SEM) of HSV-1 DNA in tears were 340 +/- 35, 1074 +/- 320, and 630 +/- 51 for groups 1, 2, and 3, and in saliva were 238 +/- 35, 963 +/- 462, and 493 +/- 25, respectively, for groups 1, 2, and 3.

CONCLUSIONS

No correlation was found between HSV-1 shedding and valacyclovir and valacyclovir with aspirin treatment. The HSV-1 DNA copy number was not reduced by treatment with 500 mg of valacyclovir daily or with a combination of daily valacyclovir (500 mg) plus twice-daily doses of aspirin (350 mg) over 30 days.

Asymptomatic shedding of herpes simplex virus (HSV) in the oral cavity

OBJECTIVE

The aim of this study was to investigate the rate of herpes simplex virus (HSV) shedding from the oral cavity, because recent studies suggest that shedding is more frequent than originally reported. Factors that could influence the rate and duration of shedding from the oral cavity were examined.

METHODS

Existing epidemiologic data from 22 reports of HSV shedding from more than 3,500 individuals were analyzed with regard to demographics, frequency of sampling, and methodologic assays.

RESULTS

HSV-1 was more likely to be detected than HSV-2 in the oral cavity of asymptomatic persons (7.5 odds ratio, 95% confidence interval 4.4-12.8; P < .0001). The rate of shedding was highly variable among individuals, ranging from none to 92% of days tested, and occurred in seropositive and seronegative individuals. In cell culture studies, the rate of detection on a single day was 6.3%. Polymerase chain reaction studies provided a different picture. HSV-1 DNA was present in 97 of 180 patients (53.9%) at multiple visits, with a rate of daily detection of 33.3%. The mean duration of shedding was between 1 and 3 days, but more than 3 days in about 10% of patients.

CONCLUSIONS

At least 70% of the population shed HSV-1 asymptomatically at least once a month, and many individuals appear to shed HSV-1 more than 6 times per month. Shedding of HSV-1 is present at many intraoral sites, for brief periods, at copy numbers sufficient to be transmitted, and even in seronegative individuals. The dental implications of these findings are discussed.

Effect of prophylactic valacyclovir on the presence of human herpesvirus DNA in saliva of healthy individuals after dental treatment

Human herpesviruses (HHVs) are ubiquitous pathogens that intermittently reactivate from latency. Transmission is believed to be facilitated by their frequent appearance in saliva. This study sought to understand the factors that influence the appearance of these viruses in saliva by examining the prevalence, pattern, and quantity of all eight HHVs in saliva of immunocompetent adults with a history of recurrent oral herpes simplex virus (HSV) infections following dental treatment and antiviral therapy. Valacyclovir or matched placebo was given (2 g twice on the day of treatment and 1 g twice the following day) to 125 patients in a randomized, double-blind controlled trial. Saliva, collected on the day of dental treatment and 3 and 7 days later, was analyzed using real-time quantitative PCR. At all visits, HHVs coinfected saliva. Over the course of the week, the DNAs of HHV-6 and HHV-7 were detected significantly more often (97% to 99% of patients) than Epstein-Barr virus (EBV; 64.8%), HSV-1 (13.0%), HHV-8 (3.2%), cytomegalovirus (2.4%), HSV-2 (0%), and varicella-zoster virus (0%), irrespective of drug treatment (P < 0.002). Mean genome copy numbers were highest for HSV-1 and HHV-6. Dental treatment did not influence asymptomatic viral shedding patterns. However, valacyclovir treatment resulted in significantly fewer patients shedding EBV at both postoperative visits compared with placebo (P < 0.008). These results suggest that HHVs are simultaneously present in the saliva of healthy adults at levels that could facilitate transmission, and valacyclovir therapy decreases the prevalence of EBV in saliva but has little effect on HHV-6 and HHV-7.

HSV-1 DNA in tears and saliva of normal adults

PURPOSE

To assess the frequency of shedding of herpes simplex virus type 1 (HSV-1) DNA in tears and saliva of asymptomatic individuals.

METHODS

Fifty subjects without signs of ocular herpetic disease participated. Serum samples from all subjects were tested for HSV IgG antibodies by enzyme-linked immunosorbent assay (ELISA) and for HSV-1 by neutralization assay. HSV-1 DNA copy number and frequency of shedding were determined by real-time polymerase chain reaction (PCR) analysis of tear and saliva samples collected twice daily for 30 consecutive days.

RESULTS

Thirty-seven (74%) of the 50 subjects were positive for HSV IgG by ELISA. The percentages of positive eye and mouth swabs were approximately equivalent: 33.5% (941/2806) and 37.5% (1020/2723), respectively. However, the percentage of samples with high HSV-1 genome copy numbers was greater in saliva than in tears, which may have been a result of the sample volume collected. Shedding frequency in tears was nearly the same in men (347/1003; 34.6%) and women (594/1705; 34.8%); in saliva, men had a higher frequency of shedding (457/1009; 45.3% vs. 563/1703; 33.1%, men versus women). Overall, 49 (98%) of 50 subjects shed HSV-1 DNA at least once during the course of the 30-day study.

CONCLUSIONS

The percentage of asymptomatic subjects who intermittently shed HSV-1 DNA in tears or saliva was higher than the percentage of subjects with positive ELISA or neutralization antibodies to HSV. Because most HSV transmission occurs during asymptomatic shedding, further knowledge of the prevalence of HSV-1 DNA in tears and saliva is warranted to control its spread. Shedding is simple to study, and its suppression may be an efficient way to evaluate new antivirals in humans.

Varicella-zoster virus reactivation is an important cause of acute peripheral facial paralysis in children

BACKGROUND

Reactivation of herpes simplex virus type 1 is thought to be a major cause of adult idiopathic peripheral facial paralysis or Bell's palsy. However, few studies have examined the pathogenesis of this condition in children. Serologic assays and polymerase chain reaction (PCR) analysis of paired sera and saliva samples were used here to investigate the causes of acute peripheral facial paralysis in pediatric patients.

METHODS

A total of 30 children with acute peripheral facial paralysis were recruited. Paired sera were assayed for evidence of herpesvirus, mumps virus or Borrelia infection. PCR was used to detect herpes simplex virus type 1 and varicella-zoster virus (VZV) DNA in saliva samples.

RESULTS

Ramsay Hunt syndrome with accompanying zoster lesions was diagnosed clinically in 2 patients, and VZV reactivation was confirmed serologically. VZV reactivation in the absence of zoster (zoster sine herpete) was diagnosed in 9 patients with either serologic assays or PCR. Thus VZV reactivation was demonstrated in 11 of 30 (37%) patients. The prevalence of VZV reactivation among patients between 6 and 15 years of age was significantly higher than in those younger than 5 years of age (53% versus 9%, P = 0.023).

CONCLUSIONS

Our data indicate that VZV reactivation is an important cause of acute peripheral facial paralysis in children, especially those between 6 and 15 years of age.

Secretion and dynamics of herpes simplex virus in tears and saliva of patients with Bell's palsy

OBJECTIVE

For clarification of the direct relationship between the reactivation of herpes simplex virus and the development of Bell's Palsy, a detection of the virus genome by deoxyribonucleic acid diagnostics and a quantitative analysis of its time-course change are both needed. The authors detected the HSV genome in specimens from patients with Bell's Palsy, quantified its number of copies, and examined time-course changes.

SUBJECTS AND METHODS

The subjects were 16 patients with Bell's Palsy. The tear fluid and saliva from the submandibular gland and the parotid gland were separately collected from the affected and unaffected sides twice or more. A total of 244 specimens were subjected to extraction of deoxyribonucleic acid, polymerase chain reaction, and microplate hybridization.

RESULTS

Herpes simplex virus-1 deoxyribonucleic acid was detected in 38 specimens (11.8%) from 5 patients (31%). The high detection (28.5%) was obtained within 2 weeks after onset. Detection at 3 weeks and later (2.8%) was significantly lower ( < 0.05). In three cases, deoxyribonucleic acid was also found on the unaffected side in the initial phase of the disease, but detection on that side (18.9%) was significantly lower than on the affected side (83.8%) ( < 0.01). The number of copies of the herpes simplex virus-1 genome was large on the affected side and early after the onset of the disease.

CONCLUSIONS

The reactivation of herpes simplex virus-1 on the affected side is involved as a pathogenic factor of Bell's Palsy. A reactivation of herpes simplex virus-1 may be generated even on the unaffected side in the early phase of the disease. Herpes simplex virus deoxyribonucleic acid was not detected in any of the examined specimens collected from the remaining 11 cases. The need for constant study to clarify other causative factors of Bell's Palsy remains.

Detection of herpes simplex virus DNA in serum and oral secretions during acute recurrent herpes labialis

Although herpes simplex virus (HSV) has been detected in the peripheral blood of immunocompromised patients and in neonates with disseminated disease, the extent to which the virus may be present in the blood during a localized infection in otherwise healthy patients is still unknown. Literature on patterns of HSV shedding into the oral cavity at the prodromal stage of the disease, during recurrences, and also during asymptomatic periods is still lacking. The present study aims at the detection of HSV DNA in the serum and oral secretions during acute herpes labialis using a highly sensitive technique, the polymerase chain reaction (PCR). The study included 10 patients with acute herpes labialis and five healthy controls. Using PCR, herpes simplex virus DNA was detected in the serum of seven patients (70%) and in the saliva of nine patients (90%). One of the control cases showed positive HSV DNA in the saliva (20%). There was good statistical agreement between the presence of HSV DNA in the serum and saliva. Frequency of attacks, patient's age, and gender had no statistically significant effect on the presence of the virus in serum or in saliva. It is concluded that HSV viremia during attacks of recurrent herpes simplex is more frequent than previously appreciated.

Salivary defense factors in herpes simplex virus infection

Saliva may contribute to a lowering of the infectious herpes simplex virus (HSV) dose during transmission and consequently abrogate infection or lead to decreased reactivation. To test this hypothesis, we assayed saliva for innate defense factors, immunoglobulin content, and the capacity to interfere with HSV infection. Serum or salivary anti-HSV IgG levels did not correlate with control of recurrent labial herpes (RLH) and were significantly higher in subjects with RLH compared with asymptomatic seropositive subjects. Although no differences in levels or output rate of innate defense factors between the groups were observed, the salivary neutralizing activity correlated with lactoferrin and hypothiocyanite concentrations in the asymptomatic seropositive group. Our results suggest that saliva contains factors, in addition to anti-HSV immunoglobulins, that neutralize HSV and may indirectly contribute to the control of RLH.

Primary graft failure caused by herpes simplex virus type 1

PURPOSE

To present a cluster of four patients with primary graft failure (PGF) who consecutively underwent a penetrating keratoplasty (PKP) during a period of 17 days in one institution. PKP was performed for reasons unrelated to herpes simplex infection. Herpes simplex virus type 1 (HSV-1) is presented as the possible cause of these PGFs.

METHODS

Viral culture of conjunctival swabs and of a bandage contact lens was performed on VERO, MRC-5, and Hep-2 cells. The four patients underwent subsequent regrafting. Polymerase chain reaction (PCR) for HSV-1 was carried out on aqueous humor and on a sample of iris and cornea with primers. Aqueous humor specimens were pretreated by boiling, and a qiagen extraction was performed according to the instructions of the manufacturer on biopsies of iris and cornea. Immunohistopathology was performed with polyclonal antibodies directed against HSV-1 and -2.

RESULTS

Culture of a conjunctival swab in three patients and culture of a bandage contact lens in the fourth patient were positive for HSV-1. In three of the four patients, PCR was positive for HSV-1 on aqueous humor and corneal graft tissue. PCR on iris tissue was positive in all patients. In three patients, culture for HSV-1 of aqueous humor and of iris tissue could not be carried out because of insufficient sample. Viral culture of the iris tissue in one patient and of the corneal graft in the four patients were negative. Immunohistopathologic examination was positive for HSV-1 in three cases.

CONCLUSION

These case reports strongly support the hypothesis that HSV-1 can be the cause of PGF.

Herpes simplex virus epidemiology and ocular importance

PURPOSE

To review the changing epidemiology of herpes simplex disease and correlate it with the epidemiology of ocular herpes simplex disease.

METHOD

A review of pertinent reports in the world literature about the epidemiology of herpes simplex and specifically about ocular herpes simplex.

RESULTS

In developed countries, many individuals are reaching adolescence and adulthood without prior herpesvirus infection. Herpes simplex genital infection is increasing at a rapid rate in sexually active adolescents and adults, with about one in six adults now infected in the United States. Similar statistics are confirmatory worldwide in developed countries. Active herpes simplex infection is a risk factor for acquisition of human immunodeficiency virus. The Herpetic Eye Disease Study, as well as prior studies from Moorfields Eye Hospital and the Mayo Clinic in Rochester, Minnesota, provides us with the epidemiology of ocular herpes simplex. Recent studies suggest an older age of onset and perhaps overall more severe ocular disease as compared with the older literature.

CONCLUSIONS

Herpes simplex is a significant health concern at present with genital infections increasing in epidemic proportions. This is also reflected in a rise in the incidence of neonatal herpes. Herpes simplex virus type 1 (HSV-1) infection is being acquired for the first time in an older age group. A significant and increasing proportion of genital herpes is caused by HSV-1. Serologic studies are no longer as useful in distinguishing orofacial herpes from genital herpes. More acute retinal necrosis syndrome cases are associated with HSV-2. Speculation about the future of ocular herpes is made based on this changing epidemiology.

Advances in diagnosis and management of herpetic uveitis

Herpetic eye disease is common and is frequently associated with intraocular inflammation or uveitis. Despite recent advances in measuring anti-herpes virus antibodies and viral DNA in ocular fluids, diagnosis remains largely clinical. The two more common syndromes include anterior uveitis, often associated with keratitis, and the acute retinal necrosis (ARN) syndrome. Treatment is complex and requires careful monitoring to provide the appropriate balance of antiviral medication and corticosteroids. Long-term prophylaxis with oral antiviral agents may be required in selected patients to help prevent the vision-compromising complications associated with recurrences.

Prospects for control of herpes simplex virus disease through immunization

Herpes simplex viruses (HSVs) can cause a variety of infections, including genital herpes. Despite effective antiviral therapy, HSV infections remain a significant worldwide public health problem. Vaccines offer the best hope for controlling spread and limiting HSV disease. This article discusses the pathogenesis and immunobiology of mucocutaneous HSV infections, summarizes the spectrum of diseases caused by HSV, and provides a review of the field of HSV vaccine research. This article also discusses what might be realistically expected of a vaccine intended for control of genital herpes and explores the question of whether a vaccine that is effective in controlling genital HSV disease might also be effective in controlling nongenital HSV disease. The efficacy of such vaccines for the full spectrum of HSV disease will eventually determine the timing and targeting of immunization, ranging from selective immunization in preadolescence to universal childhood immunization as part of the routine childhood regimen.

Oral shedding of herpes simplex virus type 1: a review

Herpes simplex virus type 1 (HSV-1) and, to a lesser extent, type 2 (HSV-2) are the aetiological agents of recrudescent herpes labialis (RHL). The available literature on patterns of HSV-1 shedding into the oral cavity at the prodromal stage of disease, during recrudescences and also during asymptomatic periods, is reviewed, as are the potential sources of virus and the known trigger factors leading to viral reactivation. Attention is given to the methodologies in use for the detection of HSV-1 and the relevance to the risk of cross-infection in surgery. This review also discusses the increase in incidence of HSV-1 genital infections and the significance of salivary inhibitors of the herpes simplex type 1 virus.

Newly acquired herpes simplex virus keratitis after penetrating keratoplasty

BACKGROUND

After penetrating keratoplasty for reasons unrelated to herpes simplex virus (HSV) keratitis, any nonspecific epithelial defect may still be caused by HSV. The purpose of this study is to determine the incidence of newly acquired herpetic keratitis and to assess contributing factors.

METHODS

The authors retrospectively studied the results of 2398 penetrating keratoplasties performed between 1980 and 1995. Three typical case histories are discussed.

RESULTS

Of 2112 patients in whom the primary diagnosis was not related to HSV keratitis, 18 presented with epithelial herpetic keratitis in their corneal graft. The incidence of newly acquired herpetic keratitis after penetrating keratoplasty was 1.2 per 1000 person-years. In most cases, the infection occurred in the first 2 years after the transplantation. Most often, well-known reactivating stimuli could have caused the HSV infection.

CONCLUSIONS

Herpes simplex virus keratitis may develop after penetrating keratoplasty even without a clinical history of HSV in the host. Thus, HSV should be considered in the differential diagnosis of a postpenetrating keratoplasty epithelial defect. The high incidence of this infection in the first 2 years after such surgery suggests a causal relation between corneal transplantation and the HSV infection.

Slow viral replication of HSV-1 is responsible for early recurrence of herpetic keratitis after corneal grafting

BACKGROUND

The presence of herpetic DNA has been shown in diseased and healthy corneal tissue. A clinical correlation with the activity of the disease has not yet been demonstrated. This study was done to evaluate the use of DNA amplification for HSV-1 from different sites for the clinical prognosis after corneal grafting.

PATIENTS AND METHODS

Eighteen patients with herpetic keratitis, 8 patients with other forms of keratitis, and 15 patients with corneal disease unrelated to herpes undergoing penetrating keratoplasty were investigated. From these, aqueous humor was obtained at the time of surgery. The excised cornea was divided into three parts for paraffin embedding, 24 h tissue culture and preparation of minced tissue. All samples were processed for HSV-1 glycoprotein D PCR followed by Southern blot and DNA hybridization.

RESULTS

In the herpes group, target DNA was detected in 4/18 aqueous humor samples, 7/16 minced tissue preparations, 6/18 explant culture fluid samples and 4/15 paraffin sections. In the control groups of other keratitis and non-herpetic eye disease, respectively, target DNA was found in 0/5 and 2/12 aqueous humor samples, 1/6 and 0/12 minced tissue preparations, 0/8 and 0/15 explant culture fluid samples and in 1/6 and 1/14 paraffin sections. Five of six patients in whom herpes DNA was detected in the short-term tissue culture experienced an episode of herpes reactivation, within 4 months after transplantation, whereas only one of the remaining patients in all three groups did so (p = 0.0005).

CONCLUSION

A slow viral replication may be responsible for early recurrence of herpetic keratitis after corneal grafting. Detection of herpetic DNA in short-term tissue cultures from explant tissues may help to define the patients at risk.

Detection of herpes simplex virus (HSV) in the saliva from 1,000 oral surgery outpatients by the polymerase chain reaction (PCR) and virus isolation

Herpes simplex virus (HSV) was detected by a polymerase chain reaction (PCR) in 47 (4.7%) out of 1,000 saliva samples from the outpatients of an oral and maxillofacial surgery department compared with 27 (2.7%) by conventional virus isolation. There were 20 PCR-positive, culture-negative cases but no culture-positive, PCR-negative cases. Patients younger than 10 years or older than 60 years secreted HSV more frequently than the others. Those with inflammatory diseases showed higher positivity for HSV than those with malignancy, trauma or other complaints. All 27 virus isolates were typed as HSV type 1 and none were resistant to acyclovir, arabinofuranosyl-adenine, iododeoxyuridine or phosphonoacetic acid.

Reactivation of latent herpes simplex virus by excimer laser photokeratectomy

We tested whether excimer laser photorefractive and phototherapeutic keratectomy may reactivate latent herpes simplex and cause recurrent keratitis in mice. Two of ten latently infected mice that were treated with ten excimer laser pulses to the corneal epithelium shed herpes simplex virus type 1, as did four of ten mice that were treated with 50 excimer laser pulses. Ocular shedding of herpes simplex virus was detected in four of ten mice that were treated with ethylenediamine-tetraacetic acid (EDTA) scraping of the corneal epithelium without laser keratectomy, and in six of ten mice on which combined EDTA-facilitated epithelial removal was performed followed by the application of ten excimer laser pulses. In both EDTA-treated groups, viral shedding was prolonged and 18 of 20 mice developed marked corneal opacification or neovascularization, or both. Corneal photoablation with the excimer laser may induce reactivation of latent herpes simplex virus, even in mice with clear and smooth-appearing corneas, and should be considered in the differential diagnosis of humans with persistent corneal epithelial defects after refractive or therapeutic excimer procedures.

Biology and molecular aspects of herpes simplex and varicella-zoster virus infections

The herpes simplex and varicella-zoster viruses are members of the subfamily alpha herpesviruses with specific properties of the virion and with the capacity to establish latent infections in humans. The genome of each of these viruses has been determined with an estimate of the number of genes and proteins encoded. The biology and molecular events of the herpes simplex virus productive and latent infection have been detailed with the use of both in vitro and in vivo model systems. The neuron is the site of latency in the ganglia with a limited transcription of genes expressed during the latent period. The specific molecular regulation of latency and reactivation are not well established. There are co-cultivation, electron microscopy, and biochemical studies that support the concept of corneal latency, although this has not been proven conclusively. Details about the varicella-zoster virus biology and molecular events are not as well advanced since animal models have been lacking. The biology of the productive infection (varicella) is different from herpes simplex virus infection since the portal of entry is the respiratory system. Data support the concept of the maintenance of latency within satellite cells in the ganglia rather than within neurons. There are multiple genes expressed during this latency. These features may explain the different clinical presentations and course of reactivation (zoster) compared with herpes simplex virus reactivation.

Systemic acyclovir and penetrating keratoplasty for herpes simplex keratitis

Corneal graft survival in 13 patients (14 eyes) receiving oral acyclovir following corneal transplantation for herpes simplex keratitis was compared to that in nine patients (9 eyes) who underwent penetrating keratoplasty for herpes simplex keratitis without receiving postoperative acyclovir. Mean age, duration of disease, and time of follow-up did not differ in the two groups. There were no recurrences of herpes simplex keratitis in any patient receiving acyclovir during a mean follow-up of 16.5 months compared to a 44% (4/9) recurrence rate in patients without acyclovir during a mean follow-up of 20.6 months (p < 0.01). Graft failure occurred in 14% (2/14) of acyclovir treatment eyes and in 56% (5/9) of the grafts in patients not receiving acyclovir. Long term prophylactic oral acyclovir significantly decreased the recurrence of herpes simplex keratitis and reduced corneal graft failure in patients with a history of recurrent herpes simplex keratitis who underwent corneal transplantation.

Suppression of ocular herpes recurrences by a thymidine kinase inhibitor in squirrel monkeys

5'-Ethynylthymidine, an inhibitor of viral thymidine kinase (TK), was given intraperitoneally to squirrel monkeys previously infected by the ocular route with Rodanus strain herpes simplex virus. Spontaneous ocular recurrences were reduced during therapy, compared to saline-treated controls. This is the first in vivo demonstration that a viral TK inhibitor can reduce recurrences of HSV-1. Similar benefit would be expected for HSV-2 and perhaps VZV (varicella zoster virus).

Herpes simplex virus: molecular biology and the possibility of corneal latency

Herpes simplex virus (HSV) is known to be latent in ganglionic neurons. Over the past eight years, a series of reports have described the isolation of HSV after organ culture of human corneas that had been removed in the course of penetrating keratoplasty. None of the corneas showed any clinical signs of active herpetic disease immediately before keratoplasty. Studies in rabbits and mice confirmed that HSV can be recovered from corneas by organ culture long after primary infection has subsided. Recently, sophisticated techniques of molecular biology, such as specific DNA or RNA probes, have been used to detect HSV nucleic acids in the cornea. The crux of the matter is whether the virus recovered from or detected in the cornea is 1) truly latent in cell populations that are nonneuronal; 2) resident in the cornea, replicating at a slow rate; or 3) newly arrived in the cornea following ganglionic reactivation. The evidence suggests that a guarded case can be made for limited HSV latency within corneal cells. HSV corneal latency would allow for reactivation, replication, and the immune response to occur in the absence of ganglionic HSV reactivation. Such a localized phenomenon has not, however, been demonstrated to occur clinically.

External ocular herpesvirus infections in immunodeficiency

Infections of the eye with members of the herpes family of viruses (e.g. HSV, CMV, VZV) are frequent manifestations of acquired and inherited defects in cell mediated immunity. Herpesvirus infections in the immunocompromised may reflect frequent viral reactivation from the latent state, as well as extensive productive infection of ocular structures following reactivation or primary infection. A review of experimental and clinical studies of both acquired and inherited immune dysfunction implicates specific immune mechanisms influencing the establishment of latency, viral reactivation and the control of active viral replication in ocular tissues.

Ocular shedding of herpes simplex virus

The presence, frequency, and relationship of ocular and oral shedding of herpes simplex virus to previous herpes keratitis was investigated. This was to determine if a history of herpes keratitis predisposes to shedding of the herpes simplex virus into the tear film and/or mouth. Swabs were collected from the eyes and mouth of two groups of patients thrice weekly over a two- to four-month period. Group A comprised nine patients with a history of herpes labialis, group B 15 patients with a history of herpes keratitis. Herpes simplex virus type 1 was isolated from 1.33% of mouth specimens but was not identified in any of the ocular specimens. There was no significant difference between groups A and B in terms of ocular or oral shedding. Oral shedding appears to be independent of a previous herpes keratitis. The tear film is an unlikely source of virus in persons either with no history of herpes keratitis or between attacks in those patients with a history of previous herpes keratitis.

Shedding of herpes simplex virus type 1 into saliva

The shedding of herpes simplex virus Type 1 (HSV-1) into saliva was studied in 110 healthy individuals, 55 patients who were undergoing oral surgery, and 21 immunocompromised patients in an asymptomatic Japanese population. Specimens were collected regularly for up to 2 months from each individual. Virus was recovered on at least one occasion from 4.5% of the healthy individuals, 20% of the patients undergoing oral surgery and 38% of the immunocompromised patients. In those individuals that shed virus, the duration of shedding varied from a mean of 1.2 days in the healthy individuals to 5.8 days in patients undergoing oral surgery, and was 3 days in the immunocompromised patients. The majority of oral surgery patients shed HSV-1 into saliva within 7 days after surgery and immunocompromised patients shed virus almost continuously. The role of surgery in triggering the reactivation of latent HSV-1, and the differences in rates of viral shedding between American and Japanese are discussed.

Effect of immunization and immunosuppression on induced ocular shedding and recovery of herpes simplex virus in infected rabbits

Immunization and immunosuppression were evaluated during latent ocular herpes simplex virus, type 1 (HSV-1) infection in the rabbit, using the following parameters: (1) ability to recover virus from preocular tearfilm cultures; (2) reactivation of latent infection by direct electrical stimulation; and (3) recovery of virus from latently infected ganglia by whole-cell co-cultivation. Immunization prior to ocular inoculation of virus significantly reduced both the titer of virus shed into the tearfilm and the duration of virus shedding during primary ocular infection. Half of the non-immunized control rabbits died secondary to virus encephalitis, whereas none of the immunized rabbits died. The immunized rabbits could not be induced to shed virus by electrically stimulating the trigeminal ganglion directly. Immunosuppression of latently infected rabbits with high-dose cyclophosphamide (300 mg kg-1) enhanced virus shedding in the tearfilm and increased mortality due to viral encephalitis. Low-dose cyclophosphamide immunosuppression (40 mg kg-1) did not increase mortality because of viral encephalitis. Tearfilm virus shedding secondary to electrical induction in high-dose and low-dose cyclophosphamide animals was higher than that of control, non-immunosuppressed animals.

Adrenergically induced recurrent HSV-1 corneal epithelial lesions

Herpes simplex virus type 1 (HSV-1) ocular shedding and recurrent HSV-1 corneal epithelial lesions were assessed after ocular iontophoresis of 0.1% 6-hydroxydopamine followed by topical ocular instillation of 0.1% Propine in ten rabbits latently infected with HSV-1 strain McKrae. Iontophoresis was performed once at 0.5 mAmp for five minutes and 0.1% Propine drops were instilled four times a day beginning three days after iontophoresis and continuing for five consecutive days. Over an eight day period beginning three days after iontophoresis, ocular tear film samples were collected on Dacron swabs with care taken to avoid contact with the corneal epithelium. The corneas were examined daily for the presence of epithelial lesions using a slit-lamp biomicroscope. Three types of lesions were observed: deep punctate lesions, dendritic lesions, and geographic epithelial defects. The ratio of positive HSV-1 eye swabs to total eye swabs was 36/157 (23%). The ratio of total positive days of corneal lesions to total days was 40/160 (25%). There were 23 deep punctate lesions, 13 dendritic lesions, and four geographic epithelial defects. There were 24/36 (67%) positive HSV-1 eye swabs associated with concurrent HSV-1 corneal epithelial lesions. There were 105/121 (87%) negative eye swabs with concurrent negative slit-lamp examinations. Chi square analysis showed significant (p less than 0.001) association of HSV-1 positive eye swabs and HSV-1 corneal lesions. These results suggest that adrenergic ocular treatment may induce both HSV-1 ocular shedding (reactivation) and HSV-1 corneal epithelial lesions (recurrence) in rabbits latently infected with HSV-1 strain McKrae.

Spread of HSV-1 to the mouse eye after inoculation in the skin of the snout requires an intact nerve supply to the inoculation site

Infection of the eye following inoculation of herpes simplex virus on the skin of the snout was monitored using slit lamp examination of the eye, isolation of virus from eyewashings and identification of virus antigens in whole corneal epithelial sheets by peroxidase-antiperoxidase staining. Infection of the eye was prevented by removing a section of the sensory nerves which supply the inoculation site. This provided evidence that spread from the skin of the snout to the eye occurred via the nerves.

A case report of tracheobronchitis by herpes simplex virus, type I

Herpes simplex virus (HSV) infection of the lung and lower respiratory tract has been thought to be a rare and fatal disease, usually in patients with immunosuppression, severe burns, or prolonged intubation. However, recently, increasing numbers of patients have been reported to have a localized infection and some of them have recovered without specific therapy.

In Korea, there has been yet no proven case of HSV infection of the lower respiratory tract. Recently, we saw a case of localized HSV infection of the tracheobronchus. A 78-year-old male patient was admitted in acute respiratory failure, with COPD and old pulmonary trberculosis. After the clinical condition improved, a bronchoscopy was done which revealed a localized area of swelling, hyperemia, and mucosal irregularity at the lower trachea and right upper lobar bronchus. Bronchial brushing and biopsy showed typical cytologic changes including intranuclear inclusion body. Viral culture of a bronchial washing revealed a growth of HSV, type I. The patient died of unrelated, acute myocardial linfarction.

Sequential analysis of antibody responses in serum, aqueous humor and tear film during latent and induced recurrent HSV infections

To study HSV specific antibody responses during latent HSV infection and induced HSV ocular shedding, rabbits were infected binocularly with McKrae strain HSV-1. The titer and class of anti-HSV antibody response in serum, aqueous humor and eye washes were determined sequentially during latent HSV infection and following intentional reactivation. In all instances the only antibody class detected was IgG. The highest anti-HSV titers were in the serum and aqueous humor, whereas a significantly lower level of anti-HSV IgG was found in eye washes. Anti-HSV IgG antibody titers were consistently 100-fold higher in serum than in the aqueous humor, which suggests an absence of local ocular antibody synthesis. Neither anti-HSV IgM nor secretory IgA antibodies were detected in any samples.

Antibody-dependent cellular cytotoxicity mediated by polymorphonuclear leukocytes and mononuclear cells against HSV-1 infected primary cultures of rabbit corneal epithelium

The roles of rabbit polymorphonuclear leukocytes (PMNL) and mononuclear cells (MC) for the regulation of ocular herpes simplex virus-1 (HSV-1) infection were studied. The antibody-dependent cellular cytotoxicity (ADCC) mediated by PMNL and MC from normal rabbit peripheral blood was assessed kinetically employing a specific 51Cr release assay. The HSV-1 infected primary cultures of rabbit corneal epithelium (PRCE) were used as the target cells to obtain a homologous assay system. The PRCE was prepared by an epithelium outgrowth technique and identified by electron microscopy. The expression of the surface HSV-1 antigens on PRCE was examined by indirect immunofluorescent staining; the cell population stained by fluorescein increased from 40% at 3 hr postinfection (PI) to 100% at 8 hr PI. To determine how early the cytotoxicity occurs, PRCE were infected with HSV-1 for 2 hrs. After 2 hrs, the ADCC was checked every 10 min for the first 40 min and then at 1, 2 and 4 hr of incubation. The cytotoxicity was apparent at 10 min postincubation and reached 46% by PMNL and 40% by MC at 4 hr postincubation (6 hr PI). Significant cytotoxic effect (26% by PMNL and 16% by MC) occurred as early as 3 hr PI. When the one-step growth cycle of HSV-1 was studied in the PRCE, HSV-1 had an eclipse period of 4 hr and a rise period of 8 hr. This suggests that rabbit PMNL and MC have the potential to eliminate the HSV-1 infected rabbit corneal epithelium before HSV matures in the cells.

Pathogenesis of herpes simplex labialis: excretion of virus in the oral cavity

Excretion of herpes simplex virus (HSV) in the oral cavity was studied in eight human subjects with a history of herpes labialis. Serial intraoral specimens were obtained by gargling broth and examined for virus by centrifugal inoculation of primary human amnion cells. Forty-seven of 637 specimens (7.4%) contained HSV. The majority of isolates (62%) were found in clusters, and the rate of excretion was significantly increased during the common cold (21%) and after oral trauma (17%) (P = 0.001 and 0.04, respectively). Oral HSV excretion often occurred in parallel with episodes of herpes labialis but could not be attributed to viral contamination from a labial lesion. Each patient excreted only one strain of HSV type 1 as determined by restriction endonuclease analysis with KpnI and BamHI. Unexpectedly, prodromal symptoms of herpes labialis were commonly not followed by development of a lesion (false prodrome). False prodromes were associated with a high rate of oral HSV excretion (60%). Intraoral ulcers on the gingivae and hard palate were frequently associated with oral HSV excretion (31%) and are the most likely source of HSV in the oral cavity.

Concomitant herpes-monilial esophagitis: case report with ultrastructural study

Herpesvirus and Candida albicans are each well-known pathogens associated with esophagitis, and concomitant infections by both agents are occasionally observed. The case of a 58-year-old man who had been treated for carcinoma of the tonsil and died of confluent bronchopneumonia is presented. Autopsy revealed an esophagitis in which cytologic changes of viral infection were seen in the intact esophageal epithelium along with pseudomycelia of Candida albicans within the ulcer bed. In addition, ultrastructural study showed dual infection by Candida and herpesvirus within individual esophageal epithelial cells at the ulcer edge, a unique demonstration of coexistent intracellular infection.

Herpes simplex virus-specific serum immunoglobulin a: detection in patients with primary or recurrent herpes infections and in healthy adults

A sensitive radioimmunoassay was used to determine levels of herpes simplex virus (HSV)-specific immunoglobulin A (IgA) in serial serum samples drawn from patients with primary HSV infections and from persons with recurrent HSV infections, and in single samples from 90 healthy adults. Significantly rising HSV IgA titers were detected in patients with primary infections, whereas those with recurrent infections had nonfluctuating titers. Sera of IgG-seropositive healthy adults were all positive for HSV-specific IgA without special pretreatment.

The significance of the arginine and arginase of tears in experimentally-induced herpes simplex corneae

Experimental corneal herpes is always accompanied by the accumulation of arginine, the substrate of arginase, in tears, ensuring the multiplication of the herpes hominis virus. The main source of the large amount of arginine is the desquamating corneal epithelium, since after the epithelium of the cornea is abraded the arginine content of the tears again equals that of healthy tears. The low arginase content of rabbit tears can be supplemented by arginase applied as eyedrops, and this results in the cure of the herpetic process.

Activation of latent herpesvirus hominis in explants of rabbit trigeminal ganglia: the influence of immune serum

More than fifty albino rabbits were inoculated into the right scarified cornea with 10(7) PFU of the Kupka strain of human herpes virus type 1 (HHV-1). At intervals ranging from 4--280 days post infection (p.i.), both gasserian ganglia, both trigeminal nerve trunks and pieces from brain stem and from both corneas were explanted. Activation of the latent HHV-1 was found mainly in the homolateral ganglion tissue, but also in explants originating from the opposite ganglia. Within 24--72 hours, prior to the release of virus into the medium, one infectious unit of HHV was recovered from 10(4)--10(5) cells of the ganglion explant. In addition, a few neurons and satellite cells revealed the presence of virus-specific antigens when the explants were examined by immunofluorescence in serial sections. If the gangia were explanted in the presence of immune serum, the virus recovery rate was at least twice lower as compared to the virus activation in explants kept in the absence of immune serum.