Sero-Detection of Cytomegalovirus and Rubella Virus IgG Antibodies Among Sudanese Pregnant Women in Khartoum State-Sudan

Background: Cytomegalovirus and Rubella virus are the most common causes of congenital infections, which increase morbidity and mortality at birth and one of the common causes of abortion in developing countries. Methodology: Plasma samples obtained from 87 pregnant womens, the samples were obtained from Omdurman Friendship Hospital 53(61%), AL-Saudi Specialized Hospital 21(25%) and Ultra lab Diagnostic Centre 13(14%).all samples were examined for presence of CMV and Rubella virus IgG antibodies by using an ELISA test. Results: The result showed that out of 87 blood samples investigated, 64(73.6%) were positive for CMV, while the reslt 23(26.4%) were negative and 85(97.7%) were positive for rubella, while the reslt 2(2.3%) were negative, where was 62(71.2%) samples had both CMV and Rubella virus IgG antibodies, 25(28.8%) had either CMV or Rubella virus IgG antibodies and there was no sample negative for both CMV and Rubella virus IgG antibodies. Conclusion: The present study observed the high prevalence rate of CMV and rubella virus IgG antibodies among pregnant women in Khartoum State. The level of infections is higher in pregnant women without history of miscarriage than those aborted women.


Introduction
Congenital CMV infection is one of the TORCH infections (toxoplasmosis, rubella, CMV, and HSV), which carry a risk of significant symptomatic disease and developmental defects in newborns [1]. Human cytomegalovirus (HCMV) belongs to the β-herpesvirus subfamily, and although most healthy individuals remain asymptomatic subsequent to infection, the pathogen is a major contributor to birth defects and to life-threatening disease in immunocompromised patients [2][3][4]. As with all viruses, HCMV depends on the host cell to provide macromolecular building blocks for virion production, and throughout the course of its evolution, HCMV has adapted to manipulate numerous fundamental cellular processes, including RNA accumulation [5], translation [6], metabolism [7][8], secretory pathways [9], and the cell cycle [10]. Cytomegalovirus infection during pregnancy is a major cause of congenital infection worldwide with an incidence of 0.2 -2.2% of live births. Up to 15% of such children have newborns following intrauterine CMV infection [11]. Infection in the newborn can be acquired through close contact (via contaminated blood, urine, and secretions), vertically through Trans placental transmission, and postnatal through breast milk [12].
Rubella virus (RuV) is a small enveloped single-stranded RNA virus and the sole member of the Rubivirus genus.
Rubivirus and alphaviruses together comprise the Togaviridae [8]. While alphaviruses are generally transmitted by mosquito vectors, RuV spreads by airborne transmission between humans [13]. The only known host [9]. RuV causes a mild childhood disease commonly referred to as German measles [8][9][10]. Rubella (initially known as German measles) is associated with an 80% risk of usually multiple congenital abnormalities if acquired in the first 12 weeks of pregnancy [14], especially the first 8-10 weeks, and leads to fetal growth problems or still birth [15].
The virus initially replicates in the nasopharyngeal mucosa and local lymph nodes, and in pregnancy infects the placenta and developing fetus.

Study design and duration
A descriptive Cross-sectional study was conducted to detect Human Cytomegalovirus and Rubella virus IgG Antibodies among pregnant women attending Omdurman Friendship Hospital, Al-Saudi Maternity Hospital and Ultra Lab Diagnostic Centre, Khartoum, Sudan. During the period from May to June 2016.

Collection and preparation of samples
A peripheral blood specimen was collected from each pregnant woman into EDTA-containing vacutainer tubes, centrifuged at 3000 RPM for 5 minutes and the obtained plasma was stored at -20°c until used.

Immunoassay for HCMV and Rubella virus IgG antibodies detection
Plasma samples were examined for anti HCMV and Rubella virus IgG antibodies by an indirect Enzyme-linked Immunosorbent Assay (ELISA) kit (foresight, Acon laboratories, Inc., 10125Mesa Rim Road, San Diego, CA92121, and USA).

Data Analysis
Statistical analysis was done by using Statistical Package for Social Science program (SPSS-version 16).

Results
A total of eighty seven blood samples (n=87) were collected from pregnant women in Khartoum State. All specimens were examined for the presence of CMV and Rubella virus IgG antibodies using an ELISA kits.
Out of 87 blood samples investigated, 85(97.7%) and 64(73.6%) were reactive for anti-CMV and anti-Rubella IgG antibodies, respectively. Of particular interest, 62(71.2%) samples were reactive for both anti-CMV and anti-Rubella IgG antibodies, whereas there was no sample showed non reactive result for neither anti-CMV nor anti-Rubella virus IgG antibodies (Table 1).

Discussion
Human cytomegalovirus and Rubella virus are two of the vertically transmitted infections that lead to congenital abnormalities and pregnancy problems. Studies showed that women who are exposed to cytomegalovirus and/or Rubella virus for the first time during pregnancy may have a higher risk of miscarriage. These infections can lead to important complications on pregnancy for maternal and fetal health [16,17]. The present study aimed for detection of anti-CMV and anti-Rubella virus IgG antibodies among pregnant women in Khartoum State.
A total of 87 blood samples investigated, 67(73.6%) and 85(97.7%) were positive for anti-CMV and anti-Rubella virus IgG antibodies, respectively. Our CMV result (73.6%) was similar to that obtained in western Sudan [18] who reported that 72.2% of pregnant women were anti-CMV-IgG antibodies reactive, but higher than result obtained in Mexico, (65.6%) by Luis et al. [19] and less than those obtained in Nigeria (91.1%) by Hamid et al. [20], in Palestine (96.6%) by Tahani et al. [21] and in China (98.7%) by Lingqing et al. [22]. These differences might be attributed to endemic variations of these countries with CMV infections and different health policies enrolled in these countries. Of particular interest, the highest frequencies of reactive anti-CMV IgG antibodies were observed among the first trimester of pregnancy and those without history of miscarriage. However, no significant difference (P > 0.05) was observed among the three trimesters of pregnancy. While Rubella virus results (97.7%) were higher than that obtained in Nigeria and Sudan 70% and 65.3%, respectively [18,23], and in line with the result obtained in Mozambique is almost 100% [24,25]. A number of studies reveal variable results of the seroprevalence of rubella over different continents; 54.1% in Nigerian [26], 76% in Sri Lanka [27], 77.5% in Russian [28] and 93% in Eritrea [29]. These differences may be due to endimicity variations of these countries with rubella infections and recent introduction of Rubella vaccine alone or in combination as MMR vaccines in national immunization schedule.
In the present study, the higher (54%) incidence of seropositivity for rubella virus IgG antibody was observed in pregnant women without history of miscarriage than that of the normal pregnancy (43.8%) outcomes group, suggested that rubella could be a cause of repeated pregnancy wastage in those women. Similar evidence was seen in Punjab, India that higher (73.2%) incidence was seen in the adverse pregnancy outcome group than the normal (69.5%) obstetric outcome group [30].
Our finding detected that the highest seropositivity of rubella virus was reported in those pregnant women within the third trimester (55.2%) of gestation than others. However, no significant difference (P >0.05) was observed among the three pregnancy trimesters.

Conclusion
According to our results we conclude that there are high prevalence rate CMV and rubella virus IgG antibodies among pregnant women in Khartoum State. The level of infections is higher in those pregnant women without history of miscarriage than those aborted women and statistical analysis shows that there is no significant association between CMV and rubella virus infections and abortion.
From this study, we observed that the high prevalence rate of CMV and rubella virus infections were found in those women in the third trimester of gestation and those within the age group ≥ 25 year-old. The present study also concludes that there is a high rate of mix infections by CMV and Rubella virus among pregnant women.