Scattering of Rubella IgG Titer in Cytomegalovirus IgG Sero- Positive Adult Women in Bangladesh

1Department of Biochemistry, Primeasia University, Dhaka, Bangladesh 2Department of Public Health Nutrition, Primeasia University, Dhaka, Bangladesh 3Department of Clinical Laboratory, Dhaka Hospital Ltd., Bangladesh 4Department of Biochemistry and Molecular Biology, University of Dhaka, Bangladesh Department of Biochemistry and Molecular Biology, Rajshahi University, Bangladesh Department of Biochemistry and Biotechnology, USTC, Bangladesh


Introduction
Cytomegalovirus (CMV) infection is frequently seen in developing countries and it is commonly asymptomatic in adults. It causes inherited CMV infection, especially in early pregnancy, infectious mononucleosis in young subjects and severe infections in immunocompromised patients. Inherited CMV infection may result in hepatitis, hepatos-plenomegaly, petechial skin eruption, multiple organ failure, microcephaly, mental retardation, chorioretinitis and cerebral calcification (Crumpacker and Zhang, 2010;Tekerekoğlu et al., 2003;Akinci et al., 2007). Rubella is a severe viral infection seen in children and adults. It is characterized by skin eruption, fever and lymphadenopathy. Besides, it can cause inherited rubella syndrome in the children of pregnant patients. It may clue to many irregularities regarding heart, eye, central nervous and haematopoietic systems in the infected newborn (Efe et al., 2009;Gershon, 2010;Aydin et al., 2009). Maternal Cytomegalovirus (CMV) is the commonest viral infection in perinatal period and it is the principal cause for inherited CMV infection with a permanent hearing, vision loss and neurological impairment (Alford et al., 1990;Tabatabaee and Tayyebi, 2009;Cannon et al., 2010). While CMV has asymptomatic infection, rubella infection is mild or self -limiting disease, transmitted through respiratory system and to growing fetus through placenta (Ojala et al., 1973). Although, incidence of rubella infection is abridged worldwide, some African countries like Mozambique still has a high incidence (95.3%) (Barreto et al., 2006;Robertson et al., 2003). Rubella vaccine is costeffective and cost-beneficial, therefore since year 2000 WHO proposed an introduction of rubella vaccine program in each country (Elnahas et al., 2003).
There is no published data concerning rubella seroprevalence in CMV IgG sero-positive adult women in Bangladesh. The basic data concerning rubella infections in adult women is important for health planners and care providers. Thus, the aim was to investigate seroprevalence for rubella infections among CMV IgG sero-positive adult women in Bangladesh. This work was the part of collaborative projects between Primeasia University and Dhaka Hospital Ltd., Bangladesh.

Materials and Methods
This was a cross-sectional study conducted at Dhaka Hospital Ltd. Bangladesh during the period of Jan-July 2014. Throughout this study we reviewed the testing records of CMV IgG sero-positive adult women aged of 17-36y were approached to participate in the study. Four age groups of CMV IgM positive patients were generated namely 17-21y, 22-26y, 27-31y and 32-36y respectively. Five mls of blood were collected in plain tubes, allowed to clot and centrifuged at room temperature. Enzyme-Linked Immunosorbent Assay (ELISA) was used for CMV and rubella (IgG) using commercial diagnostic kits (DRG Instruments GmbH. Germany). Quantitative analysis for CMV and rubella IgG were performed and the assay result interpreted as IU/ml. The manufacturer's instructions were followed for the cutoff points, which was <9 IU mL −1 for CMV IgG while <10 IU mL −1 was considered negative for rubella IgG, respectively. Between January, 2014 to July, 2014, 51 anti-CMV IgG positive adult women were included and retrospectively evaluated in this study.

Statistics
Data were entered in the computer using SPSS for windows version 16.0 and double checked before analysis. P value <0.05 was considered significant.
Even if, 22-26 age group assigned with highest CMV IgG positivity but the highest mean CMV IgG titer (301.60 IU mL −1 ) was found in 32-36 age group. With utilization of paired sample t test between age group and anti-CMV IgG titer, it was found non-effective relationship of anti-CMV IgG with age groups and p value was >0.05. As shown in Fig. 2.

Prevalence of Anti-Rubella IgG Titer among Adult-Non Pregnant Women
In Fig. 3, the sero-positivity for anti-Rubella IgG was found in 46 (90.19%) while 9.81% (5) was recorded as sero-negativity of anti-Rubella IgG. The highest anti-rubella IgG positivity was acknowledged in 22-26 age group (37.25%, n = 19) however the lowest sero-positivity was counted in 32-36 age group (9.81%, n = 5). The rates of sero-positivity and negativity of anti-rubella IgG are also presented in Fig. 3.
In comparing to anti-CMV IgG positivity and titer distribution, the rates of anti-rubella IgG positivity showed different prevalence patterns, presented in Fig. 4 and the highest anti-rubella IgG titer was found in 27-31 age group (116.36 IU mL −1 ) while 99.03 IU mL −1 was documented in 17-21 age group adult women. Figure 2 explained the anti-rubella IgG titer distribution of 51 adult-non pregnant women selected in this study.

Discussion
To our knowledge this the first published data in Bangladesh concerning epidemiology of rubella infection among CMV IgG positive adult women. In the current study, the prevalence of Rubella IgG seropositivity was 90.19% in CMV IgG positive adult women. Middle age group 22-26y showed highest incidence of CMV IgG positivity (41.2%, p<0.05) and rubella IgG positivity (37.25%, p<0.05). However, much higher prevalence of CMV was reported in South East Asia (Taechowisan et al., 2007), while European countries show low prevalence (Picone et al., 2009).
In this study, it found that the scattering of CMV IgG and rubella IgG titer were statistically non-significantly (p>0.05) with age specifications.
Likewise, low socio-economic status has been found as a strong risk factor for acquisition CMV infection (Bukbuk et al., 2002). Nevertheless in Bangladesh it is difficult to investigate the socioeconomic status of these adult women because the culture is based on generous hospitality attitude toward guest and family members who usually lives in extended families.
The current study has many limitations; one of these we did not use Polymerase Chain Reaction (PCR) of the viral DNA isolation. The other limitation is the lack of follow-up for these women in order to document seroconveration and to detect fetal infections.

Conclusion
This study shows the prevalence of 90.19% of rubella infections among CMV IgG sero-positive adult women in Bangladesh. Rubella vaccine is endorsed for adult women. Additional research is required.

Ethics
This article is original and contains unpublished material. The corresponding author confirms that all of the other authors have read and approved the manuscript and no ethical issues involved.