Sir,

I am grateful to Beare and Batumba for drawing attention to my failure to include squamous cell carcinoma (SCC) of the conjunctiva in my short article. I concentrated on super-infection as that was the subject I was given for my lecture and hence formed the basis of the article. Despite this it seems likely that SCC, given the much higher increased risk in HIV-positive people, is associated with an oncogenic infection in addition to ultraviolet radiation and immunosuppression. If this is true, then SCC would be a disease similar to Kaposi's sarcoma and anal neoplasia in being increased in HIV-positive people and associated with specific infections (HHV8 for KS and HPV for anal carcinoma).

However, I feel that the perspective of SCC as gained from a specialist Eye Hospital will give a somewhat biased view of how common SCC is. Morgan et al1 when describing ophthalmological complications in the MRC Ugandan cohort concludes that although ocular complications of AIDS seem to comprise a large extra element in the work-load of tertiary care hospitals dealing with eye problems, on a population basis such cases are infrequent. Even Newton et al2 in their comprehensive paper acknowledge that in Uganda, SCC is not a particularly common manifestation of HIV disease but they estimated that HIV accounts for around 60% of the population attributable fraction of SCC.

However, I should have drawn attention to SCC, even if just to acknowledge that as yet we do not know whether it is caused by a super-infection. I am therefore grateful that omission has been corrected by these letters.