Sociodemographic factors associated with IgG and IgM seroprevalence for human cytomegalovirus infection in adult populations of Pakistan: a seroprevalence survey.

Saira Ibrahim,Waquaruddin Ahmed,El-Nasir M A Lalani,Amna R Siddiqui,Anwar A Siddiqui,Paul A H Moss

doi:10.1186/s12889-016-3772-8

Abstract

BackgroundThe seroprevalence of human cytomegalovirus (HCMV) infection ranges from 30 to 90 % in developed countries. Reliable estimates of HCMV seroprevalence are not available for Pakistan. This study determined the seroprevalence and sociodemographic factors associated with HCMV infection in adult populations of Karachi, Pakistan.MethodsA seroprevalence survey was conducted on 1000 adults, including residents of two semi-urban communities, and visitors to a government and a private hospital. Questionnaire-based interviews were conducted. Sera were analysed for HCMV-specific IgG and IgM. Chi-square or Fisher’s exact test was used for comparing sociodemographic variables against seropositivity of HCMV-IgG or IgM. Multiple logistic regression modeling was performed for IgG seroprevalence and adjusted odds ratios were computed.ResultsThe seroprevalence of HCMV-IgG and IgM was 93.2 and 4.3 % respectively. 95.3 % of individuals who were IgM seropositive were also seropositive for IgG. Around 6 % (15/250) of women of childbearing age remained uninfected and were therefore susceptible to primary infection. HCMV-IgG seroprevalence was associated with being female (p = 0.001), increasing age (p = 0.002) and crowding index (p = 0.003) and also with lower levels of both education (p < 0.001) and income (p = 0.008). Seroprevalence also differed significantly by marital status (p = 0.008) and sampling location (p < 0.001). A logistic regression model for HCMV-IgG seroprevalence showed associations with being female (OR = 1.89; 95 % CI: 1.10–3.25), increasing age (OR = 3.95; 95 % CI: 1.79–8.71) and decreasing income (OR = 0.72; 95 % CI: 0.54–0.96). A strong association was observed between increased seroprevalence of HCMV-IgM and decreasing household size (p = 0.008).ConclusionsSeroprevalence of HCMV is very high in Pakistan, although 6 % of women of childbearing age remain at risk of primary infection. The IgM seropositivity observed in some individuals living in small household size (1–3 individuals) with persistent HCMV infection could have resulted from a recurrent HCMV infection. Future longitudinal research in pregnant women and neonates is required to study the trends in HCMV seroprevalence over time in Pakistan for the development of a potential HCMV prevention and vaccination programme.

Highlights

The seroprevalence of human cytomegalovirus (HCMV) infection ranges from 30 to 90 % in developed countries
Our results reveal a high seroprevalence of HCMV infection, with an average of 93.2 % of individuals aged ≥ 18 years, showing the presence of HCMV-specific IgG antibodies indicative of persistent infection
Our findings reveal that up to 6 % of women of childbearing age remain HCMV seronegative in Pakistan, and the risk of primary infection within this group may be significant given our observation that around 0.5 % of men of a similar age may be undergoing primary infection each year, an event followed by prolonged viral secretion, which could serve to drive infection in the women who remain uninfected at this age

Summary

Introduction

The seroprevalence of human cytomegalovirus (HCMV) infection ranges from 30 to 90 % in developed countries. This study determined the seroprevalence and sociodemographic factors associated with HCMV infection in adult populations of Karachi, Pakistan. Upon primary infection, which is usually asymptomatic [3], HCMV establishes a state of lifelong latency, during which infectious virus is difficult to isolate [4]. Active HCMV infection can result from primary infection in a previously seronegative individual or reactivation in a seropositive individual [5] in response to immunosuppression and inflammation [6]. Seroprevalence of HCMV varies from 30 to 90 % in most developed countries [1] and the seroprevalence is dependent on sociodemographic factors [7]. Seroprevalence is reported with increasing age [7] and an inverse correlation with socioeconomic status [17, 18]

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