An emergent poxvirus from humans and cattle in Rio de Janeiro State: Cantagalo virus may derive from Brazilian smallpox vaccine.

The biological properties of poxvirus isolates from skin lesions on dairy cows and milkers during recent exanthem episodes in Cantagalo County, Rio de Janeiro State, Brazil, were more like vaccinia virus (VV) than cowpox virus. PCR amplification of the hemagglutinin (HA) gene substantiated the isolate classification as an Old World orthopoxvirus, and alignment of the HA sequences with those of other orthopoxviruses indicated that all the isolates represented a single strain of VV, which we have designated Cantagalo virus (CTGV). HA sequences of the Brazilian smallpox vaccine strain (VV-IOC), used over 20 years ago, and CTGV showed 98.2% identity; phylogeny inference of CTGV, VV-IOC, and 12 VV strains placed VV-IOC and CTGV together in a distinct clade. Viral DNA restriction patterns and protein profiles showed a few differences between VV-IOC and CTGV. Together, the data suggested that CTGV may have derived from VV-IOC by persisting in an indigenous animal(s), accumulating polymorphisms, and now emerging in cattle and milkers as CTGV. CTGV may represent the first case of long-term persistence of vaccinia in the New World.

Terminal region sequence variations in variola virus DNA.

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.

Topography of variola smallpox virus inverted terminal repeats.

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.

Recombinant vaccinia/Venezuelan equine encephalitis (VEE) virus expresses VEE structural proteins.

cDNA molecules encoding the structural proteins of the virulent Trinidad donkey and the TC-83 vaccine strains of Venezuelan equine encephalitis (VEE) virus were inserted under control of the vaccinia virus 7.5K promoter into the thymidine kinase gene of vaccinia virus. Synthesis of the capsid protein and glycoproteins E2 and E1 of VEE virus was demonstrated by immunoblotting of lysates of CV-1 cells infected with recombinant vaccinia/VEE viruses. VEE glycoproteins were detected in recombinant virus-infected cells by fluorescent antibody (FA) analysis performed with a panel of VEE-specific monoclonal antibodies. Seven E2-specific epitopes and two of four E1-specific epitopes were demonstrated by FA.

Recombinant vaccinia virus/Venezuelan equine encephalitis (VEE) virus protects mice from peripheral VEE virus challenge.

Mice immunized with recombinant vaccinia virus (VACC) expressing Venezuelan equine encephalitis (VEE) virus capsid protein and glycoproteins E1 and E2 or with attenuated VEE TC-83 virus vaccine developed VEE-specific neutralizing antibody and survived intraperitoneal challenge with virulent VEE virus strains including Trinidad donkey (subtype 1AB), P676 (subtype 1C), 3880 (subtype 1D), and Everglades (subtype 2). However, unlike immunization with TC-83 virus, immunization with the recombinant VACC/VEE virus did not protect mice from intranasal challenge with VEE Trinidad donkey virus. These results suggest that recombinant VACC/VEE virus is a vaccine candidate for equines and humans at risk of mosquito-transmitted VEE disease but not for laboratory workers at risk of accidental exposure to aerosol infection with VEE virus.

Serosurvey for "acute hemorrhagic conjunctivitis" virus (Enterovirus 70) antibodies in the Southeastern United States, with review of the literature and some epidemiologic implications.

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.