PREVALENCE AND ASSOCIATED RISK FACTORS FOR HERPES SIMPLEX TYPE 1 VIRUS AMONG DENTAL STUDENTS

Abstract

Observance of safety principles is essential during the dental treatment for the dentist, patient, clinical staff and their families. Since dental students are in close contact with patients during their education and are exposed to crossinfection, if the infection control principles are not adhered, the probability of transmission of HSV1 virus to them increases through the saliva and mucus secretions of patients. [...]100 individuals from 3 different education levels (basic sciences, pre-clinical, clinical) filled in the questionnaire. According to Table 2, no statistically significant difference was observed in the mean IgG titer in terms of gender, marital status, educational level and age in the studied students (P>0.05), however the IgG antibody titer in subjects with a history of herpes was significantly higher than in those without a history (p<0.001). According to the results of the present study, the mean of HSV1 antibody titer in different age groups increased with age, but the difference was not significant.

Headnote

Abstract

Introduction. Dental practitioners have a close relationship with many patients and are at risk of cross-infection. Therefore, HSV-1 infection is a potential occupational hazard for dental workers. The aim of this study was to determine the seroprevalence of HSV1 and associated risk factors in dental students of Birjand in 2018-2019. Materials and methods. This cross-sectional study was done on 100 dental students, selected by random sampling. After taking their written consent, they were tested for antibodies to herpes simplex type 1 virus (HSV-1), by taking a peripheral blood sample (5 ml) and an antivirus antibody, and the Serum 25-hydroxy vitamin D (1.25(OH)2D₃) levels were measured using an AntiHerpes-1 IgG kit with ELISA, by a pathologist. Logistic regression and chi-square were applied to investigate the relationship between the variables of interest, at a significance level of 5%. Results and discussion. 41% of the subjects had contacts with the HSV1 virus and were carriers of antibodies. The mean serum 25-hydroxy vitamin D3 levels were 23.22+13.09. The prevalence of HSV1 antibody at pre-clinical and clinical levels was higher than in literature. Also, the results of logistic regression showed a significant association between HSV1 and history of herpes (OR=2.37, p<0.001), educational level (OR=1.48, p=0.04) and deficiency of vitamin D3 (OR=1.33, p= 0.02). Conclusions. Patients with a previous recurrent history of herpes labialis (RHL) seem to be at higher risk. Dentists should be aware of this potentially severe post-extraction complication, even if occupationally acquired HSV has been less reported, due to the personal protective barriers used.

Keywords: herpes simplex virus infections, cross-infection, dental student.

1.INTRODUCTION

Herpes simplex type I virus (HSV-I) is a member of the a-herpesvirus family [1]. The recrudescence of HSV infections requires simultaneous viral reactivation at trigeminal ganglia level [2]. RHL can also complicate dental procedures, fixed prosthodontic tissue, and surgery of the oral cavity [3]. The prevalence of HSV-1 infection increases from childhood, seroprevalence being inversely related to the socioeconomic background. Most early HSV infection is caused by HSV-1, infection by HSV-2 being extremely common [4].

Recurrent HSV-1 is infrequent within the mouth in otherwise healthy patients, although, in immunocompromised patients, it can be more aggressive. The diagnosis of common herpetic infection can be usually based on the clinical history and laboratory diagnosis and present features. These two viruses can infect the mouth or genitals; generally, nevertheless, HSV-1 is considered to give rise to infections 'above the waist' and HSV-2 'below the waist'.

For establishing the latent infections with intermittent shedding, particularly in the oral cavity and perioral regions, dental surgeons and their staff are likely to be especially at risk. Crossinfections are very likely to be transmitted during dental procedures, due to direct and frequent contact with blood, saliva and other body fluids, and also to indirect contact with contaminated surfaces, as well as airborne particles [5].

In recent years, despite diseases such as hepatitis AIDS, HSV infections, focus was put on infection transmission and on the antibody level of dentists and dental students, due to the risk of infection transmission.

Also, the prevalence of infections in the dental profession is high, because these persons are more exposed to blood, saliva and risk of sharps [6]. There are only a few reports of HSV crossinfection in dental practice. The frequency of herpetic whitlow was observed to be higher among practising dentists, compared to the normal population. However, reports confirming the transmission of infection from the patient to the dental team are available in literature [7]. Also, cross-infection of HSV from dental team to patients has been evidenced. A dental hygienist with herpetic whitlow who did not use gloves routinely infected 20 out of 46 patients [8].

Observance of safety principles is essential during the dental treatment for the dentist, patient, clinical staff and their families. Since dental students are in close contact with patients during their education and are exposed to crossinfection, if the infection control principles are not adhered, the probability of transmission of HSV1 virus to them increases through the saliva and mucus secretions of patients.

The aim of this study was to determine the prevalence of antibodies to herpes simplex type 1 virus (HSV 1), and to investigate the associated risk factors for evaluating the risk of this occupational infection in dental students in 2018-2019.

2.MATERIALS AND METHODS

For this cross-sectional study, dental students of Birjand University of Medical Sciences were selected using random sampling method over a 6 month period, between 2018-2019. The sample size was estimated according to the following formula, in which the prevalence of HSV1 was considered equal to 42%:

(ProQuest: ... denotes formula omitted.)

where Z² is constant, p is the prevalence and d is the estimated error risk. As a result, 100 individuals from 3 different education levels (basic sciences, pre-clinical, clinical) filled in the questionnaire. This provided demographic data and details on medical background including history of previous blood transfusion, history of genital or oral lesions and use of any antiviral or immunosuppressive drugs. The qualified dental surgeons were also asked questions related to the number of years they had been in practice, and the number of needle stick injuries suffered. A 5 ml sample of peripheral blood was collected from each participant into a plain bottle. The serum was separated and stored at -28°C prior to serological testing. Then, the presence of anti-virus antibodies was evaluated by a pathologist, using a dedicated Anti-Herpes-1 IgG kit by the Enzyme-Linked Immunosorbent Assay (ELISA) method.

The study was approved by the Ethics and Scientific Committee of Birjand University of Medical Sciences, Iran (approval code: bums.1394.11).

Statistical Analysis

Data is represented as mean±SE, or as frequency and percent values. Analysis between groups and variables was performed with Student's t-test and chi-squared test. Also, logistic regression was applied to determine the associated risk factors. Statistical analysis was conducted in SPSS, ver. 21. All statistical tests were carried out at a 0.05 level of significance.

3.RESULTS

A total of 100 dental students (43 males and 57 females) with mean age of 22.8 ± 3.9 participated in the study. Their demographic characteristics are presented in Table 1.

According to Table 1, 31% of the subjects had a history of herpes, and 1% had a history of taking antiviral drugs.

The mean of IgG titer in the studied students was 16.1±17.2, and 59% of them had negative antibody titer.

According to Table 2, no statistically significant difference was observed in the mean IgG titer in terms of gender, marital status, educational level and age in the studied students (P>0.05), however the IgG antibody titer in subjects with a history of herpes was significantly higher than in those without a history (p<0.001).

There was a statistically significant difference risk of HSV1 amongst participants with deficient level of vitamin D3 versus other level (P =0.02, OR: 1.338). The history of herpes is statistically related to the risk of HSV1 (P <0.001, OR: 2.37). Also, students of clinical educational level had significant higher risk of HSV1 than other educational levels (P =0.041, OR: 1.48). However, other variables, such as sex, had no statistical relationship with HSV1 (Table 3).

4.DISCUSSION

In dental surgery, cross-infection may occur by direct or indirect contact, aerosols or inoculation injuries. All of them are potentially relevant to the spread of herpes viruses. The purpose of this survey was to determine the potential risk factors associated with occupational risk of HSV1 in dental students.

The results of this study showed that most of the students had negative antibody titer. Other studies showed similar results [9,10,11]. Various studies conducted in industrialized countries have reported different results [12]. The difference in antibody titer may be due to the social situation and age groups.

According to the results of the present study, the mean of HSV1 antibody titer in different age groups increased with age, but the difference was not significant. Other researchers from different countries, such as Sweden, Italy, Germany and Switzerland, have reported age as an effective factor in increasing rates of HSV1 antibody titers, which is similar to the results of this study [9,13,14].

Another finding of this study showed that the prevalence of positive IgG antibody in men is higher than in women, but there was no significant relationship between gender and HSV1 antibody titers. Other studies presented similar results [15,16]. Also, some studies reported a higher prevalence of antibodies in women than in men, which is not consistent with the results of our study. Other studies showed no significant difference between gender and HSV1 antibody, which is consistent with our results [17,18].

Results of logistic regression showed that clinical educational level students are in higher risk of HTLV1. A study examining the seroepidemiology of herpes virus among dental workers and students showed no significant difference between HSV1 antibody and educational level, yet the antibody level in clinical students was higher than in pre-clinical ones, which is probably due to more contacts of these students with patients.

This study also demonstrated the effects of vitamin D3 deficiency on the risk of positive HSV1. Another study indicated that D3 administration may be useful as a complementary therapeutic option for the treatment of inflammatory diseases [19,20]. Additionally, the obtained results of this study showed that a history of herpes in students increases significantly the odds of HSV1, because persons with anti-HSV antibody may have received oral HSV infection during childhood, but they did not recur and therefore did not report it.

5.CONCLUSIONS

The results of this study should alert all dentists care providers to consider how their students are educated for providing care about patients with HSV infections. In summary, addressing students' apprehensions might be a crucial moderator that will determine whether they will provide the best possible care for these patients in their future professional lives. Studies are recommended to increase students' awareness on the principles of infection control, when dealing with people with herpes simplex. Also recommended is that such studies should be extended with more samples. It is essential to control cross-infection in all branches of medical and dental professions, if staff and patients are to be protected from the risk of infection.

Acknowledgements. We would like to thank all study subjects for their participation and extend our thanks to the Dentistry Clinical Research Development Center, Birjand University of Medical Sciences, Birjand, Iran, for consultation and sample collection.

References

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