Congenital Infection and Congenital Cataract in Tanzania: A Case Control Study

Abstract

Background: Cataract is the commonest cause of childhood blindness in sub Saharan Africa (SSA). The significance of congenital rubella and human cytomegalovirus (HCMV) infection in the etiology is not known. Objectives: We aimed to investigate prevalence of both viruses in cases of congenital cataract and controls. Methods: Lens tissue was collected (from cases), blood and saliva from cases and controls. Using ELISA, we tested blood samples for rubella and cytomegalovirus IgM. Quantitative polymerase chain reaction (qPCR) was also used for detection of the viruses. Results: Cytomegalovirus was detected using qPCR in 72.9% saliva specimens of cases compared to 38.5% of controls (P = 0.0001). Cytomegalovirus IgM was also detected in 10.8% blood specimens of cases and only 1.5% control (P = 0.01). Rubella IgM was detected in 13.8% blood specimens of cases and only 3.1% controls (P = 0.01). In lens aspirates of cases, 12.7% were HCMV positive and 11.1% were rubella positive by qPCR. Cases had lower birth weights (mean = 2.8 kg) than controls (mean = 3.2 kg), independent of viral status (P = 0.004). Conclusions: Although most of the children in the study presented too late to be sure that infection was congenital, our study strongly suggests that HCMV and rubella infection appear important causes of congenital cataract in Tanzania hence virology testing of infantile cataract cases may be useful in assessing effectiveness of immunization programs as they are established throughout SSA.

Congenital Cytomegalovirus Infection Initially Managed as Congenital Rubella Syndrome

“…10 All three articles on CRS reviewed for this paper cited cataract as clinical manifestation, with one even specifying bilateral involvement. [7][8][9] Although Lu and Yang detected only CMV IgM and IgG in 10-11 patients of their 37 with bilateral cataract with no rubella antibodies, their positivity rates for CMV IgM and IgG in the control group were relatively close to the study group (IgM: 11.8% vs. 15.5%; IgG: 17% vs. 23.3%). 15 A case report of supposed cCMV documented bilateral cataracts as manifestation.…”

“…7 Ophthalmologists prefer not to implant an intraocular lens (IOL) immediately after cataract extraction since the rubella virus had been isolated from the lens material. 8 The exposure of the virus to the immune-privileged anterior chamber of the eye during the surgery, together with the introduction of an additional foreign body (the IOL), can cause more inflammation and may lead to surgery-requiring complications such as membrane formation, which can cover the visual axis. However, the delay in implanting the IOL, a cheap and optimal option for correction, can negatively affect visual rehabilitation despite using aphakic glasses as an alternative.…”