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Genome DNA terminal region sequences were determined for a Brazilian alastrim variola minor virus strain Garcia-1966 that was associated with an 0.8% case-fatality rate and African smallpox strains Congo-1970 and Somalia-1977 associated with variola major (9.6%) and minor (0.4%) mortality rates, respectively. A base sequence identity of > or = 98.8% was determined after aligning 30 kb of the left- or right-end region sequences with cognate sequences previously determined for Asian variola major strains India-1967 (31% death rate) and Bangladesh-1975 (18.5% death rate). The deduced amino acid sequences of putative proteins of > or = 65 amino acids also showed relatively high identity, although the Asian and African viruses were clearly more related to each other than to alastrim virus. Alastrim virus contained only 10 of 70 proteins that were 100% identical to homologs in Asian strains, and 7 alastrim-specific proteins were noted.

We examined the nucleotide sequences of the inverted terminal repeat (ITR) regions adjacent to the covalently closed hairpin end sequences of three variola major and four minor strains from smallpox outbreaks in Europe, Asia, Africa, and South America. The ITR regions ranged in size from 581 to 1051 base pairs (bp) and contained no apparent open reading frames. Two nonrepetitive sequence elements, NR1 and NR2, were conserved and resembled nonrepetitive elements in the ITRs of other orthopoxviruses. Depending on strain, the terminally positioned NR1 and the more internal NR2 flanked a direct repeat region containing from none to four copies of a 69-bp sequence and one copy of a 54-bp related sequence partial repeat. A distinctive pattern of ITR topography of NR1 and NR2 flanking a single copy of the 69-bp unit characterized each of three examined alastrim variola minor strains. A nonalastrim African minor strain from the last natural case of smallpox in Somalia in 1977 showed the largest ITR region of the examined viruses because of a second direct repeat cluster following NR2.

Acute hemorrhagic conjunctivitis (AHC) has been epidemic throughout much of the Eastern Hemisphere since its emergence in central West Africa in 1969. The disease had a distinctive clinical picture and an unusual geographic epidemiology. Between 1969 and 1975 AHC has occurred almost exclusively in crowded coastal areas of tropical countries during hot, rainy seasons. Only a few documented outbreaks have occurred in inland cities and in subtropical or temperate climate zones. Of 1014 residents of the eastern or southeastern United States who were screende for neutralizing antibodies to three or four strains of AHC virus (enterovirus type 70), three (0.3%) had titers ranging from 1:10 to 1:40. However, no clinical evidence of prior experience with AHC disease could be ascertained for these persons, so that the antigenic specificity of the detected antibodies is unknown. We conclude that populations of coastal tropical areas of northern South America and all of Central America are vulnerable to AHC epidemics.