Asymptomatic shedding of HSV-1 in patients undergoing oral surgical procedures and attending for noninvasive treatment

Covid-19 Pandemic: What Changes for Dentists and Oral Medicine Experts? A Narrative Review and Novel Approaches to Infection Containment

The authors performed a narrative review on Severe Acute Respiratory Syndrome- CoronaVirus-2 ( SARS-CoV-2) and all infectious agents with the primary endpoints to illustrate the most accepted models of safety protocols in dentistry and oral medicine, and to propose an easy view of the problem and a comparison (pre- vs post-COVID19) for the most common dental procedures. The outcome is forecast to help dentists to individuate for a given procedure the differences in terms of safety protocols to avoid infectious contagion (by SARS-CoV-2 and others dangerous agents). An investigation was performed on the online databases Pubmed and Scopus using a combination of free words and Medical Subject Headings (MESH) terms: "dentist" OR "oral health" AND "COVID-19" OR "SARS-CoV-2" OR "coronavirus-19". After a brief excursus on all infectious agents transmittable at the dental chair, the authors described all the personal protective equipment (PPE) actually on the market and their indications, and on the basis of the literature, they compared (before and after COVID-19 onset) the correct safety procedures for each dental practice studied, underlining the danger of underestimating, in general, dental cross-infections. The authors have highlighted the importance of knowing exactly the risk of infections in the dental practice, and to modulate correctly the use of PPE, in order to invest adequate financial resources and to avoid exposing both the dental team and patients to preventable risks.

Herpesviruses in Head and Neck Cancers

Head and neck cancers arise in the mucosa lining the oral cavity, oropharynx, hypopharynx, larynx, sinonasal tract, and nasopharynx. The etiology of head and neck cancers is complex and involves many factors, including the presence of oncogenic viruses. These types of cancers are among the most common cancers in the world. Thorough knowledge of the pathogenesis of viral infections is needed to fully understand their impact on cancer development.

Shedding of HSV-1, HSV-2, CMV, and EBV in the saliva of hematopoietic stem cell transplant recipients at Fundación HOMI - Hospital de la Misericordia, Bogotá, D.C

INTRODUCTION

Hematopoietic stem cell transplantation in pediatric patients is an alternative treatment for different diseases. The conditioning regimen for transplant predisposes recipients to the development of infections. Viral infections by herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), human cytomegalovirus (CMV), and Epstein-Barr virus (EBV), are the most common, and the leading cause of morbidity and mortality among these patients. These viruses lie dormant in various cell types and the reactivation of latent infections may lead to asymptomatic viral shedding in saliva. The detection of these viruses in secretions may contribute to understand the behavioral dynamics of these viral infections in transplanted patients, and to the early diagnosis of reactivation. 

OBJECTIVE

To assess HSV-1, HSV-2, CMV and EBV viral shedding in the saliva of patients admitted for hematopoietic stem cell transplantation at Fundación HOMI - Hospital de la Misericordia between January and November of 2012. 

MATERIALS AND METHODS

We evaluated stimulated saliva samples of 17 hematopoietic stem cell transplantation recipients weekly. We performed DNA extraction from saliva, and we evaluated the presence of DNA for HSV-1, HSV-2, CMV, and EBV by PCR. 

RESULTS

While we detected HSV-2 and CMV DNA in the saliva of four patients, EBV DNA was detected in nine patients with leukopenia. In contrast, we did not detect HSV-1 DNA in saliva. Additionally, four out of the 17 patients showed a simultaneous shedding of CMV and EBV. 

CONCLUSIONS

By conventional PCR, we demonstrated asymptomatic HSV-2, CMV, and EBV viral shedding in saliva, associated with leukopenia.

Delayed type hypersensitivity in the pathogenesis of recurrent herpes stromal keratitis

Recurrent herpes stromal keratitis (HSK) is one of the leading causes of blindness in the developed world. Cyokines characteristic of Th1 cells (in particular IFN-γ and IL-2) have been shown to dominate in HSK in addition to mechanisms by nonspecific, antigen-independent effector cells such as neutrophils, basophils, and monocytes. More recently, the migration and maturation of dendritic cells (DC) within the corneal stroma of patients with HSK have been recognized as contributors to recurrent disease, suggesting a role for delayed type hypersensitivity (DTH) in the immunopathogenesis of HSK. The role of DC and DTH in recurrent HSK has not been studied extensively and experimental models of recurrent HSK focusing on DTH as the pathogenesis and viral particles as the triggering antigen may contribute to better understanding of the disease.

Effects of thyroid hormone on HSV-1 gene regulation: implications in the control of viral latency and reactivation

Thyroid hormone (TH) is involved in many biological functions such as animal development, cell differentiation, etc. Variation and/or disruption of plasma TH level often led to abnormalities and physiological disorders. TH exerts the effects through its nuclear receptors (TR). Literature showed that procedures resulted in TH alteration also linked to reactivation of several viruses including Herpes Simplex Virus Type -1 (HSV-1). Bioinformatic analyses revealed a number of putative TH responsive elements (TRE) located in the critical regulatory regions of HSV-1 genes such as thymidine kinase (TK), latency associated transcript (LAT), etc. Studies using neuronal cell lines have provided evidences demonstrating that liganded TR regulated viral gene expression via chromatin modification and controlled viral replication. The removal of TH reversed the inhibition and induced the viral replication previously blocked by TH. These results suggest that TH may have implication to participate in the control of reactivation during HSV-1 latency.

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.