Seroprevalence , Type-Specific of Herpes Simplex Virus and Associated Risk Factors among Women of Child Bearing Age in Kogi State , Nigeria

Background: Viruses of the Herpes viridae family infect 90% of the Earth’s population. Humans are the hosts of at least nine unique herpes viruses. Aim: This study is aimed at evaluating the seroprevalence of type specific herpes simplex virus infection and the associated risk factors in a cross-section of asymptomatic healthy women of childbearing age in Kogi state, Nigeria. Methodology: A total of 330 females of child bearing age (15 49 years) participated in this study. They were recruited from various local government areas of three Senatorial districts of Kogi state. Blood samples were collected from participants and analyzed for HSV-1 and HSV-2 antibodies (IgG) quantitatively with ELISA kit. Results: The overall prevalence of HSV was 76.7%. Data further show that majority (96.4%) of the population studied had HSV-1, while 77% had HSV-2 infections. Results also showed that the young adults indicated prevalence of 95.7% for HSV-1 and 74.7% for HSV-2, while in the middle aged, the prevalence were 98.6% for HSV-1, and 84.9% for HSV-2. 99.2% of the married women were positive for HSV-1, while 86.9% How to cite this paper: Drisu, U.I., Oronsaye, F.E., Adejumo, B.I.G., Uchuno, G.A., Emmanuel, A.M., Dimkpa, U., Omosor, K.I., Adebowale, M.O., Abdulrahman, O.N. and Ukatu, E.N. (2018) Seroprevalence, TypeSpecific of Herpes Simplex Virus and Associated Risk Factors among Women of Child Bearing Age in Kogi State, Nigeria. Health, 10, 1006-1017. https://doi.org/10.4236/health.2018.107075 Received: June 11, 2018 Accepted: July 23, 2018 Published: July 26, 2018 Copyright © 2018 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access


Introduction
The epidemiology of herpes simplex is of substantial epidemiologic and public health interest.Worldwide, the rate of infection with herpes simplex virus-counting both HSV 1/HSV 2 is around 90% [1].Genital herpes, an infection commonly caused by human herpes simplex virus 2 (HSV-2) in Nigeria and in most regions of the world, has been described as a silent pandemic with different countries being at different stages of the epidemic [2] [3].Although many people infected with HSV develop labial or genital lesions (herpes simplex), majority are either undiagnosed or display no physical symptoms-individuals with no symptoms are described as asymptomatic or as having subclinical herpes [4].
Most individuals contract HSV infection during the first decades of life.The prevalence of HSV 1 antibody varies from 45% to 88% in adult populations and is influenced by sex, geographic location, socio-economic status and age [5].Antibodies to HSV-2 are rarely found before the age of onset of sexual activity, but HSV 2 seroprevalence increases to 35% -60% by age 60 [6] [7].This prevalence has increased dramatically since the late 70's and is highest among prostitutes (75%) and male homosexuals (83%) [6].The prevalence of HSV increases with age and number of partners with women being at higher risk than men [8].The CDC reports that 48% of African American women in the United States are infected with HSV-2 [9] [10].The largest increase in HSV acquisition during the past few years is in white adolescents.People with many lifetime sexual partners and those who are sexually active from young age are also at higher risk for

Participants
A total number of 330 asymptomatic and apparently healthy child bearing women, aged between 18 -49 years were recruited for this study from all the local government areas of the three Senatorial districts of the state.A well-structured questionnaire was administered to every participant of this study to obtain their demographic information and health history.Informed consents of participants were sought and obtained after explaining the purpose of the research.The Ethics Committee of Ministry of Health, Kogi State approved the study.

Sample Collection and Processing
An aliquot of 5 ml venous blood obtained from each subject by peripheral venopuncture was emptied carefully into a dry sterile plain bottle to avoid lysis.
The sample was allowed 1 hour to clot and retract after which it was spun using a bench centrifuge at 3000 rpm at room temperature for 10 minutes.The serum sample was then separated from the cells within an hour into a clean sterile tube and stored at −20˚C prior to the analysis for HSV-1/HSV-2 antibodies (IgG).

Sample Analysis
The following investigations were carried out on the sample to ascertain the status of the participants.

HSV-1/HSV-2 Antibody Determinations
Antibody concentrations of all the participants to HSV-1/HSV-2 were determined using ELISA kits which were commercially purchased from Calbioteck Company, USA by following the procedure given in the kit protocol.

Data Analysis
Descriptive data was expressed as mean ± standard deviation for continuous variables and percentages for categorical variables.Multinomial Logistic regression modeling was used to identify socio-demographic and behavioral risk factors that can independently predict HSV-1 and HSV-2 infections.Test of significance was set at p < 0.05.All statistics were done using SPSS/IBM software, version 20.

Results
Figure 1 shows the prevalence of Herpes Simplex virus 1 and 2 among a cross section of adult population in Kogi State.Data shows that majority [96.4% (n = 318)] of the population studied had HSV-1 and 77% (n = 254) had HSV-2 infections.
Table 2 shows the prevalence and risk of HSV-1/HSV-2 according to the age    Table 3 shows the prevalence and risk of HSV-1 and HSV-2 according to the marital status of the participants.One hundred and twenty nine (99.2%) of the married women were positive for HSV-1, while 1 (0.8%) was negative.One hundred and thirteen (86.9%) of the married women were positive for HSV-2, while 17 (13.1%)were negative.One hundred and eighty nine (94.5%) of the unmarried women were positive for HSV-1, while 11 (5.5%) were negative.One hundred and forty one (70.5%)were positive for HSV-2 and 59 (29.5%) were negative for HSV-2 respectively among the unmarried participants.Multivariate logistic regression analysis indicated that married women were at significantly greater risk for HSV-1 (p = 0.03) and HSV-2 (p ≤ 0.001) infections compared to the unmarried women.
Nineteen (100%) of the participants who had sexual intercourse before the age of 15 years were all positive for HSV-1 ( All the married participants 130 (100%) volunteered information of having sexual partners before marriage (Table 5).One hundred and three had just single sexual partner before marriage, out of which 102 (99%) were positive for HSV-1 and 1 (0.97%) was negative.Twenty seven (100%) of the participants were negative for HSV-2.Multivariate logistic regression test indicated that participants who had more than one sexual partners before marriage were not at greater risk of HSV-1 (p = 1.00) or HSV-2 (p = 1.00) infection compared to those who had a single sexual partner before marriage.

Discussion
The overall prevalence of HSV in the studied population is 76.7%.Our study indicated HSV-1 prevalence of 96.4%.This agrees with a previous study [17] done in the following countries; Bulgaria (83.9%),Czech Republic (80.6%).Also in agreement with this high prevalence rate are the works done in the Middle East [18].In Turkey they found the prevalence of HSV-1 to be 97% among pregnant women in Erzurum in Eastern Anatolia Region.However, in Istabul, 85.3% was found to be positive for HSV-1 among sexually active adults.Prevalence of these viruses was higher in sex workers of lstabul, reaching levels of 99% and 60% for HSV 1/HSV 2 respectively.Ibrahim et al., 2000 [19] reported 95% level of HSV-1 positivity among the Syrians, while Cunningham et al., [20] reported 76.5% prevalence of HSV-1 in Australia.However, low prevalence of HSV-1 was reported in Belgium (67.4%),Netherlands (56.7%), and Finland (52.4%) respectively [17].
This work recorded 77% prevalence rate for HSV-2.This is in agreement with the work done in Enugu state, Nigeria [15].They reported HSV-2 prevalence of 77.9% among female patients attending skin and ANC clinics at University of Nigeria Teaching Hospital and Enugu State Teaching Hospital.In contrast, a previous work by Pebody et al., 2004 [17] indicated prevalences of 23.9% in Bulgaria, 13.9% in Germany, Finland (13.45%),Belgium(11.1%),Netherland (8.8%), the Czech Republic (6.0%) and England and Wales (4.2%) respectively.HSV-2 seroprevalence is high in Central and South America.Infection levels are estimated at 20% to 60% [18] [24].HSV-2 is more common in Sub-Saharan Africa than in Europe or the North America.Up to 82% of women and 53% of men in Sub-Saharan Africa are seropositive for HSV-2.These are the highest levels of HS-2 infection in the world, although exact levels vary from country to country in this continent, [24].Genital herpes appears less common in Northern Africa compared to Sub-Saharan Africa.For example, only 26% of middle-aged women have antibodies for HSV 2 in Morocco [25].The prevalence of HSV 2 in Thailand is 37%, while 9% was recorded in Philippines (25).Much works have been done in the Middle East on HSV 2. Of these works were the one done among the pregnant women in Erzurum in Eastern Anatolia Region in Turkey (42%) [18], lstabul (4.8%) [26], Jordan (52.8%, men), and 41.5% (women) [27] and Israel (9.2%) [23].Cunningham et al., 2006 [20] found out in Australia that the prevalence of HSV 2 is 12% (women 16%, men 8% respectively).The number of genital herpes infections appears to be rising in New Zealand with three times more cases in 1993 compared to 1977 [28], where HSV 2 affects 60% more women than men of similar age [18].
It is noteworthy that there are limited studies done on the prevalence of herpes simplex virus infection in Nigeria.It is believed that the high prevalence of HSV infection observed in this study may be explained in part by the low awareness of the prevalence and risk factors of this viral infection and lack of sensitization of the general population to avail themselves for the HSV tests.It may also be a pointer to indiscrete sexual behavior among the studied group.
The present findings appeared relatively higher compared with studies done elsewhere among different age groups.For example, a previous study by Xu et al., 2010 [29], reported a prevalence of 16.2% among Americans aged 14 to 49 who were infected with HSV-2.Also in Ontario, the prevalence of HSV-2 in people between the ages of 15 to 16 has been shown to be 26.9% for men and 32% for non-pregnant women [30].During the mid-1980s, HSV-2 prevalence was 33% in 25 to 29-year-old women and 45% in those aged 40 and over in Costa Rica.In the early 1990s HSV-2 prevalence was approximately 45% among women over 60 in Mexico [18].The prevalence of HSV-2 in middle aged Colombian women was 60% and 54% in Haiti, while HSV-2 antibodies were found in more than 41% of women of child bearing age in Brazil [18].In South Korea, the prevalence of HSV-2 in those less than 20 years is 2.7% for men, and 3.0% for women, while for those over 20 years, the prevalence was 21.7% for men and 28% for women [31].Our data also showed that the young adults were not at greater risk of the HSV-1 and HSV-2 infections compared with the middle-aged adults.A previous study [32] reported that HSV-2 prevalence consistently increased with age in all geographic areas.Another study [33] also demonstrated that older age was associated with significantly higher odds of HSV-2 infection.
Our findings also indicated that married women were at significantly greater risk for HSV-1 and HSV-2 infections compared to the unmarried women.It is not very clear the reason for the higher risk in married women compared to the unmarried.It is however thought that those who were married were more likely to have had a past-year sex partner compared with those who were single.A previous study [34] has shown that relationship status remained an independent predictor of HSV-2 with the married status being protective for HSV-2 in those aged 30 -49 years.
Our data which indicated high prevalence of HSV infection in subjects who were exposed to sex early and those with multiple sex partners agrees with work done in Istabul [26] among sex workers, which reported prevalence of 99% and 66% for HSV-1 and HSV-2 respectively.In contrast, a lower seroprevalence of 34% for HSV-1 and 20% HSV-2 were recorded in Syria among the prostitutes and bar girls who are considered to be the high risk group [19].These findings demonstrate that the high incidence of HVS infection in most part of the world may result from early exposure to sex and multiple sex partners.However, it is noteworthy that in the present study those who had early exposure to sex and those who had multiple sex partners before marriage were not at greater risk of HSV infection compared with those who had late exposure to sex and those with single sex partners before marriage.A previous study [35] has shown that women who commenced sexual activity at 15 or younger age and those with more than one sexual partner before marriage were at greater risk of HSV compared to women who delayed sexual exposure until they were above 15 years and those who had single sex partner before marriage.

Conclusion
The prevalence of HSV-1 and HSV-2 infections is high in Kogi state.Marital status played an important role for HSV-2 and HSV-1 infections.These findings therefore indicate that health education and screening interventions are highly required, in an effort to prevent transmission to other individuals, including sex partners and offspring.There is also the need to intensify efforts toward HSV1 and HSV2 vaccine development by the government and health institutions.
Furthermore, early sex education among teenagers and continuous sex education should be encouraged among the adults.
of subjects.Data shows that the young adults (18-35 years) indicated prevalence of 95.7% for HSV-1 and 74.7% for HSV-2, while in the middle aged, the prevalence were 98.6% for HSV-1, and 84.9% for HSV-2.Multivariate logistic regression analysis further indicated that young adults did not indicate significantly greater risk for HSV-1 (p = 0.47) and HSV-2 (p = 0.08) seropositivity compared to the middle-aged adults.
The diagnosis of HVS based only on the subject medical history and physical examination is frequently inadequate, there is need to further its diagnosis using modern diagnostic techniques.There is scanty information on the prevalence of this disease in Kogi state in particular and Nigeria in general.The present study therefore was aimed at evaluating the prevalence of HSV, type specific and effects of some of its risk factors among women of reproductive age in Kogi State of Nigeria.

Table 1 .
Distribution of the study population according to their demographic characteristics and sexual behaviors.

Table 2 .
The prevalence and risk of HSV-1 and HSV-2 according to age of participants.

Table 3 .
Prevalence and risk of HSV-1 and HSV-2 according to the marital status of the participants.

Table 4
ticipants, 119 (36.06%) declined to give information on the time of their first exposure to sexual intercourse.Multivariate logistic regression test indicated that participants who had sexual intercourse before the age of 15 years were not at greater risk of HSV-1 (p = 1.00) and HSV-2 (p = 0.76) infection compared to those first exposed to sexual intercourse from 15 years of age and above.

Table 4 .
Prevalence and risk of HSV-1 and HSV-2 according to age of first sexual exposure among the participants.

Table 5 .
Prevalence and risk of HSV-1 and HSV-2 among the married participants according to number of sexual partners before marriage.