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Impact of cytomegalovirus infection as a cause of Sensorineural Hearing Loss (SNHL) in children of Basrah, Southern Iraq.

Ahmed hameed hasan*, Hassan J Hasony, Ahmad M Al-Abbasi, Samer S Aziz, Jaleel Samanje

Background: The burden of CMV-associated Sensorineural Hearing Loss (SNHL) in populations with CMV seroprevalence approaching 100% is unknown. The purpose of this study was to assess the rate, associated factors and predictors of SNHL in CMV-infected infants identified by newborn screening in a highly seropositive maternal population. Methods: Newborns with positive anti-CMV-Ab and confirmed by auditory assessment were enrolled in a prospective study to monitor the impact of CMV infection on hearing outcome using anti-CMV-IgG avidity and quantitative Polymerase Chain Reaction (qPCR). Results: Hearing functions were assessed in 357 children who underwent at least one Auditory Brainstem Response (ABR) testing. SNHL was observed in 60/357 (16.8%) children of 1-10 years of age during 1st of Dec 2020 to mid of March 2021 at the latest hearing evaluation. Profound loss (>90dB) was found in 75.4% children among them 81% with bilateral SNHL while all 2 children with unilateral loss had moderate to severe deficit. The presence of CMV infection detected in 80% of SNHL and in 8.3% of control group. Anti-CMV-IgG avidity was with high Avidity Index (AI) among 76.7% and low AI in 3.3% indicating non-primary CMV infections were the dominant. The correlation of CMV IgG avidity test for all (60) cases with SNHL disease, reveals a weak positive correlation value with (r=0.138) as more predictive and acceptable test for screening and diagnosis of child with CMV infection and the degree of SNHL disease, while the correlation of viral load (rt PCR-DNA) test for all (60) cases with SNHL disease showed a weak negative correlation with (r=-0.246), as the rt PCR is not predictive test for screening of CMV infection and degree of SNHL disease because the shedding of the virus in body fluid may be absent in latent stage of infection and not associated with anti-CMV-IgG low avidity index . Conclusion: Even in populations with near universal immunity to CMV, congenital CMV infection is a significant cause of SNHL demonstrating the importance of CMV as a major cause of non-genetic SNHL in children, Anti-CMV-IgG Avidity Index (AI) is more predictive and acceptable test for screening and diagnosis of child with CMV infection and the degree of SNHL disease.