Infectious Risk Factors for Congenital Cataract in Tanzania
Richard Bowman, MD; Sonia Vaitha, MD; Tamsyn Derick; Furahini G. Mndeme, MD
London School of Hygiene and Tropical Medicine
London , United Kingdom
Introduction: Cataract is the leading cause of blindness in children in sub Saharan Africa – the importance of congenital rubella and CMV infection in the aetiology is unknown (1-3).
Aim: To investigate the prevalence of congenital rubella and cytomegalovirus (CMV) infection in congenital cataract cases and controls
Methods: We collected lens tissue, oral fluid and dried blood spots (DBS) from 74 children (<12 months) with bilateral congenital cataract attending tertiary facilities in Tanzania. We also collected saliva and DBS from 74 age-matched controls attending Reproductive and Child Health (RCH) clinics. DBS samples from cases and controls were tested for IgM antibodies to Rubella Virus and CMV by ELISA. Molecular detection of Rubella and CMV was performed using qPCR on saliva specimens from cataract cases and matched controls and on lens tissue specimens taken from cataract cases during surgery.
Results: CMV specific IgM was detected in 9/74 (12.16%) cases. There was no case of raised CMV or Rubella IgM titres in controls. CMV was detected in 56 of 74 (75%) saliva specimens of cases compared to 25/74 (33.8%) of controls (p<0.0001). In cases, 9/74 (12.2%) lens aspirates were CMV positive; 8 of these cases were also saliva positive whereas only one was positive for saliva, lens, and DBS. Rubella specific IgM was detected in 9/74 (12.16%) cases. Only one sample was positive for both CMV and Rubella IgM. Rubella virus was detected in only 1 of 74 (1.4%) saliva samples but 9/74 12.16%) lens aspirates from cases; 4 were also serology positive. |
Discussion: Our study show that, there was no case of raised CMV or Rubella IgM titres in controls. CMV was detected in saliva specimens of cases at a higher prevalence compared to of controls. In cases, CMV was also detected in lens aspirates. Rubella specific IgM was detected in cases al a lower prevalence.
Conclusion: Both congenital CMV and rubella infections appear to be implicated in the aetiology of congenital cataract in Tanzanian children.
References: 1. Gupta, E., L. Dar, and S. Broor, Seroprevalence of rubella in pregnant women in Delhi, India. 2006.
2. Sridharan, G., et al., Serology in congenital infections: experience in selected symptomatic infants. Indian Pediatr, 1999. 36: p. 667-69.
3. Mahalakshmi, B., et al., Infectious aetiology of congenital cataract based on TORCHES screening in a tertiary eye hospital in Chennai, Tamil Nadu, India.