Research Article - (2018) Volume 9, Issue 1
Galdiero E, Crudele V, Della Rocca MT, Melardo C, Di Lella FM, Galdiero M and Franci G*
1Department of Experimental Medicine-University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Napoli, Italy
2University Hospital Luigi Vanvitelli of Naples section of Virology and Microbiology, Via Costantinopoli 104, 80138 Napoli, Italy
3Department of Biology, University of Naples "Federico II", Naples, Italy
Received Date: January 30, 2018; Accepted Date: February 05, 2018; Published Date: February 10, 2018
Citation: Galdiero E, Crudele V, Della Rocca MT, Melardo C, Di Lella FM, et al. (2018) Seroprevalence of Herpes viruses in a retrospective study in Southern Italy. Arch Clin Microbiol. Vol.9 No.1:74 doi:10.4172/1989-8436.100074
Copyright: © 2018 Galdiero E, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Information on age- and sex-specific prevalence of herpes viruses (HHV) is of importance to optimize control and prevention strategies. Using data from a population-based serological study in South Italy (n=1854) between 1/01/2016 and 30/06/2017, the main purpose of the present study was to assess the spread of HSV1-2, VZV and CMV seroprevalence in a random population. Results of seroprevalence in South Italy in the last year showed that CMV is the most frequent species with a significantly higher prevalence in women , and with infection rates increasing from childhood to adolescence. In our country, probability of seropositivity for HSV1-2 infections increase with age. A large proportion of teenagers and young adults remain HSV-1-2 susceptible and women were significantly more likely to be HSV1-2 seropositive. Similar to other European countries, varicella immunity in south Italy is acquired gradually, starting in early childhood and showing an increase around age 3–5 years even if the amount of susceptible adults aged over 20 years is still substantial.
Keywords
Seroprevalence; Herpes simplex; Varicella Zoster; Cytomegalovirus
Introduction
Human Herpes viruses (HHVs) are pathogens affecting 60-95% of the population worldwide with an ubiquitous distribution even if a great importance has been identified with geografic location, socioeconomic status and age to value the primary infection’s acquisition. Primary infection is followed by a latency phase in the host and by possible periodical reactivated infections. During latent infections, viruses involve different tissues concerning viral species interested: sensor ganglia for HSV1, HSV2 and VZV; limphocytes, monocytes and epithelium for EBV, CMV and HSV6- 8. HHVs have been also linked to the development of chronic disorder as Alzhemeir’s disease, cardiovascular disease and depression.
There are two types of HSV, HSV1 and HSV2, transmitted by direct contact with infected secretions. HSV1 is transmitted by direct contact with infected secretions, locaized predominantly in orolabial ulceration even if many infections remain asymptomaytic and, therefore, so undiagnosed. Typically, clinical lesions occur after a primary infection. Seroprevalence rates of HVS1 varied from 50-85% or more in adults from developed country in Europe, while, epidemiological studies, in Italy, showed a seroprevalence rates of 93% in the adult population [1]. HSV-2 is transmitted sexually and is one of the most common genital diseases, affecting adolescents and adults and faciliting HIV transmission. The circulation of HSV-2 is more limited, and is generally, associated with other sexually transmitted diseases affecting about 5% of the adult population in Italy [2-5]. Monitoring the epidemiology of HSV1-2 infections is of importance for the prevention of neonatal herpes and associated diseases and for determining antibody prevalence in the general population.
As regards primary varicella infection, this is considered a benign common illness of child with a life-long immunity that, in later life, could reactivate and cause herpes zoster. Although mortality is rare, varicella is more severe in old ages, pregnant women, neonates and immunocompromised individuals [6-8]. A live attenuated vaccine was developed in 1970s and an evaluation of vaccination plans in the United States reported a decrease in disease, hospitalisation and mortality but the age of infection increased with an increase of severe cases. Routine vaccination against VZV has been recently introduced in Italy recently as a national immunization programme, while was only reccomanded for non-immunized individual in the past. So there isn’t an evaluation of its efficacy and we need epidemiological data to identify risk associated with VZV seronegativity. It’s important to consider that seropositivity in adult population and high risk of infection in young children is typical in Italy such as other countries with temperate climate [9].
Human cytomagalovirus (CMV) is a highly prevalent herpes virus that infect 30-100% of population worldwide. Even if it is considered a benign infection, sometimes it causes serious diseases in immunocompromised patients and pregnant women with an active infection, but also in healthy people playing an important role in aging of the immune system. It is the most common congenital infection transmitted by maternal infection or reactivation. Early childhood infection is asymptomatic or causes a flu-like symtoms. Seroprevalence is around 40-50 % among white populations and higher about 80-100% in some non-white populations. [10,11].
To update the epidemiology of HHV infections in southern Italy, an epidemiological study was carried out to determine the seroprevalence of HSV1-2, VZV, CMV among a general population who asked for hospital care to the University Hospital Vanvitelli in the last past year.
Materials and Methods
Study design
A seroprevalence retrospective study from a general population was carried out using sera collected from patients of all ages (1-70 years) hospitalized at the University Hospital Vanvitelli in Naples Italy for different causes. During a period from 1/01/2016 to 30/06/2017, 1854 patients’s sera were analysed for detection of type-specific HSV1-2 antibodies using Elisa (Kit Instituit Virion/ Serion GmbH Ref ESR 105G-105M), CMV antibodies using enzyme immunoassay Biomerieux Vidas, IgG Ref 30204-IgM REF 30205), VZV antibodies using chemiluminescence immunoassay (Gemini Combo Alifax, IgG REF ESR 04 – IgM REF ESR 104) following manifacturer’s instructions.
Seropositivity was defined as follows according to the provider of the assay: VZV IgG measurement lower than 50 U/μl should be considered uninfected, while samples with measurement grater or equal than 100U/μl should be classified as infected; HSV1 IgG lower than 20 U/μl uninfected while grater or equal than 30 U/ μl infected; CMV IgG lower than 0,7 U/μl uninfected, reater or equal than 0,90 U/μl infected.
Statistical Data
Seroprevalences by age-group were tabulated with 95% confidence interval (CI) and comparison of differences between seropositive and seronegative subjects was performed using the Chi-squared seronegative (χ2). Odds ratios (OR) were calculated with multiple logistic regression analysis of risk factors age and gender identified from the literature as potential risk factors for seroprevalence. Data were analysed using using Statistic Toolbox in the Matlab Environment.
Results
The seroprevalence of IgG antibodies towards three of common human herpes viruses were respectively investigated. Population characteristics related to HSV1-2, VZV, CMV seroprevalence were reported in Table 1. Within total group of 1854 patients, 1149 were analized for HSV1-2, 895 for VZV and 1529 for CMV. The results for HSV1-2 antibodies detection were reported in Table 1. 762 patients were seropositive (66%) and 387 were seronegative for HSV1-2 with the mean age of 32.4 and 31.4 respectively. As reported in Table 2 with the HSV1-2 seropositive men were 341 (45%) and women 421 (55%) with a mean age of 32.3 and 32.5 respectively while a mean age of seronegative men was 28.6 and 35.1 for women. Difference in mean age between seropositive and seronegative men was statistically significant at 95% level and we found the same results for women. As shown in Table 3, in our population seroprevalence for HSV1-2 increase from childhood (66%) to adolescence (69%) because children showed antibodies against HSV1-2 or for infection or for antibodies passively acquired from maternal immunity and decrease in adults ≥ 20 (50%). The decrease trend in seropositivity for HSV1- 2, above all in adults is due to the improvement of prevention as already observed in other countries. Furthermore, as shown in Table 4. In table 4 the multiple logistic regression demonstrated that, for HSV1-2, gender was statistically significant while lower significance was associated with age. Collected data showed that women are more susceptible to HSV1-2 infections, predominantly as genital infection, because mucosal surfaces of external genitalia are more vulnerable even if in this study we didn’t distinguish orolabial infections from genital infections.
| Virus IgG antibodies | |||
|---|---|---|---|
| HSV | VZV | CMV | |
| Npositive/Ntotal | 762/1149 | 668/895 | 1098/1529 |
| % (Npositive/Ntotal ) | 66.32 | 74.75 | 71.81 |
| 95% confidence interval (Npositive/Ntotal ) | 66.19-66.45 | 74.57-74.93 | 71.71-71.91 |
| Age (IgGpositive) mean ± SD | 32.47 ± 23.50 | 32.88 ± 23.45 | 31.75 ± 23.47 |
| Age (IgGnegative) mean ± SD | 31.41 ± 23.01 | 30.64 ± 22.74 | 32.21 ± 23.35 |
| p-value for difference in mean age | 0.47 | 0.21 | 0.73 |
Table 1: Herpes virus seroprevalence.
| HSV VZV CMV | |||
|---|---|---|---|
| IgG positive women n % | 421 (55.2) | 373 (55.7) | 595 (54.1) |
| IgG positivemen n % | 341 (44.7) | 295 (44.1) | 503 (45.8) |
| Age IgGpositive M | 32.35 ± 23.67 | 32.35 ± 23.87 | 30.51 ± 23.01 |
| mean ± SD | |||
| Age IgGpositive W | 32.56 ± 23.38 | 33.30 ± 23.13 | 32.80 ± 23.82 |
| mean ± SD | |||
| p-value for difference in mean age | 0.9 | 0.6 | 0.1 |
| Age IgGnegative M | 28.62 ± 22.32 | 30.75 ± 22.17 | 32.47 ± 22.97 |
| mean ± SD | |||
| Age IgGnegative W | 35.16 ± 23.46 | 30.50 ± 23.58 | 31.29 ± 23.81 |
| Mean ± SD | |||
| p-value for difference in mean age | 0.006 | 0.93 | 0.8 |
Table 2: Relationship between presence of herpes virus IgG antibodies, and age and sex.
| HSV1-2 | VZV | CMV | |
|---|---|---|---|
| Age | % (95%CI) | % (95%CI) | % (95%CI) |
| Children (1-9) | 65.8 | 74.3 | 72.6 |
| (65.3-66.4) | (73.5-75.1) | (72.2-73.1) | |
| Adolescent (10-19) | 68.5 | 72.6 | 72.4 |
| (67.6-69.3) | (71.5-73.6) | (71.8-73.1) | |
| Adult ( ≥ 20) | 50 | 50 | 50 |
| (49.8-50.1) | (49.8-50.2) | (49.9-50.1) |
Table 3: Seroprevalence of HSV1-2, VZV, CMV by demographic variable. p-value is <0.0001 for each virus separately.
| HSV1-2 | VZV | CMV | ||||
|---|---|---|---|---|---|---|
| OR (95%CI) | p-value | OR (95%CI) | p-value | OR (95%CI) | p-value | |
| Age | 1 (0.9-1) | 0.8 | 1.1(1.06-1.1) | <.0001 | 1 (0.9-1) | 0.69 |
| Gender | 1.5 (1.3-1.8) | <.0001 | 0.8 (0.6-1.2) | 0.75 (1.06-0.9) | 0.01 | |
Table 4: Multiple logistic regression of two risk factors for herpes simplex virus, varicella zoster virus and cytomegalovirus.
The results for VZV antibodies detection were reported in Table 1. 668 were seropositive (74,7%) and 227 seronegative for VZV with a mean age of 32.8 an 30.6 respectively. Among 668 seropositive VZV patients, 295 (44%) were men and 373 (56%) were women with a mean age of 32.3 and 33.3 years respectively while between seronegative patients the mean age was in 30.7 and 30.5 respectively showing not significant differences in mean ages as reported in Table 2. We could notice that seropositivity is higher between women than between men even if the mean age of seropositivity is comparable. As shown in Table 3 the vast majority acquisition of VZV antibodies was observed in children showing a seropositivity of 74.3, 72.6, and 50% respectively. In contrast with previous studies in which Nardone et al. 2007 reported that in all countries studied over 50% of children 0-5 years and 90% adolescents 10-15 were seropositive for VZV except in Italy where was reported only 38% and 78% respectively, in our study we showed an early immunization of young population maybe due to better vaccination programmes as shown well in tab. 4 in which we demonstrated with multiple logistic regression that age was important for acquiring infection whereas gender was less significant.
A larger number of patients was tested for CMV from our population. As reported in Table 1, between all patients analysed for CMV infection 1098 were seropositive (71%) and 431 were seronegative with a mean age of 31.8 and 32.2 years respectively. We noticed, as showed in Table 2, that on 1098 seropositive patients, 503 (46%) were men and 595 (54%) were women with a mean age of 30.5 and 32.8 respectively while seronegative patients men had a mean age of 32.5 and women of 31.3 years. Also in the case of CMVs seropositivity is higher between women than in men even if the mean age of seropositivity is comparable for both. As reported in Table 3, seroprevalence was higher in children from 1 to 9 years and adolescent between 10 and 19 years decreased in adults 72.72 and 50% respectively, showing that in our region the first infection for CMV was age-dependent. As shown in Table 4, the multiple logistic regression demonstrated that, for CMV, age was not statistically significant, while gender was significant for acquiring infection.
We observed, moreover, that 665/1854 patients were tested for all three viruses and 257 were seropositive for all three, 187 for two of them, 100 for only one and 100 seronegative. As shown in Table 5a, the multiple logistic regression demonstrated that, for them, age was statistically significant, with a p-value < .0001. A final analysis about these selected patients was made considering a multiple Poisson Regression Analysis, in order to establish the statistical significance of how many different kinds of seropositivity (HSV1-2, VZV, CMV) were acquired by the patients vs. the gender and the age. The results in Table 5b, show that gender is now the more significant risk factor.
| HSV1-2; VZV | HSV1-2; VZV | |||
|---|---|---|---|---|
| CMV | CMV | |||
| OR (95%CI) | p-value | OR (95%CI) | p-value | |
| Age | 1.07 (1.06-1.08) | <.0001 | 1(0.99-1.01) | 0.98 |
| Gender | 0.82 (10.56-1.22) | 0.33 | 0.87 (0.78-0.97) | <.0001 |
Table 5: Multiple logistic regression and multiple Poisson Regression Analysis of two risk factors for herpes simplex virus, varicella zoster virus and cytomegalovirus.
Discussion
This study is the first, to our knowledge, to report the comparative seroepidemiology among HHV in Southern Italy. Few data are available on HSV1-2, VZV, CMV seroprevalence in Italy. The main importance of this study is that the detection of specific antibodies against HHV was conducted on samples randomly collected from a general population among both female and male of different age and not in subgroups even if some age groups are numerically different depending on the subjects coming to the Hospital.
Previous studies in Europe and USA reported that women have a high seropositivity against HSV1-2 than men probably because they are more biologically susceptible to HSV infections [12-14]. We found females had a higher risk of HSV1-2 infection compared to males in South Italy agreeing with previous studies in other countries. This may reflect the differential role of gender on clinical presentation, with men more likely to have asymptomatic HSV1-2 infection and could result in higher rates of male to female transmission [15-17].
Similar to other countries in Europe, varicella immunity in Italy is acquired gradually starting in early age, showing an increase around 3-5 years because in this age they are increasing possibilities for exposure and at about six years, they are already immune at school entry. Studies demonstrated that in 11 European countries with a temperate climate, VZV seroprevalence shows rapid increase during the first decade of life, while in tropical and subtropical areas, varicella affect mainly adolescents and adults [18-20]. Over than 90% of children were seropositive for VZV at 15 years with a lower proportions of seropositive individual at 5-years-old children in Italy (38%) and in Poland (48%) and a highest proportion in Netherlands (95-97%). The wide variation in transmissibility observed in different European countries is due to varying population densities, social mixing, climate differences. In our study, the proportion of immunized patients increase by age even if the immunity gained through vaccination is not considered to affect the results of our study since so far the vaccine was not widely used.
CMV prevalence increases gradually with age so that at old age the majority of people in South Italy are infected and with a higher females compared to males. The increasing age associated with increased seroprevalence for proportion of CMV is in line with reports of a significant rate of seroconversion in adults [21]. We noticed a higher incidence of infection in adult women than men. Furthermore, the increasing seroprevalence by age is in contrast with VZV for which over 50% of the population is infected at young age but is comparable with HSV1-2 with a slow increase age-specific seroprevalence. The main implication is that the majority of CMV infections is not only caused by transmission among children after primary infection, but also by older subjects going through one or more reactivation episodes. A corollary is that persistence of CMV in the population is not possible with transmission from primary infected persons only, and is dependent on infectious reactivation.
Our sampling is subject to a selection bias because samples were collected from people seeking medical helps, limiting generalization of results. Convenience of this kind of study is less costly, time-consuming and render easier the process to obtain samples. To increase study validity, we analyzed samples coming from a big hospital that reaches patients from all south Italy to receive both primary and hospital care. A high proportion of susceptible individuals in certain age of groups detected in our study, underlines a need to revise vaccine recommendations and to consider the need of a screening above all between non-immune women before pregnancy but also between all susceptible individuals because at older ages there is an increase in the risk of complications.
Acknowledgements
None
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