A critical component of laboratory surveillance for measles is the genetic characterization of circulating wild-type viruses. The World Health Organization (WHO) Measles and Rubella Laboratory Network (LabNet), provides for standardized testing in 183 countries and supports genetic characterization of currently circulating strains of measles viruses. The goal of this report is to describe the lessons learned from nearly 20 years of virologic surveillance for measles, to describe the global databases for measles sequences, and to provide regional updates about measles genotypes detected by recent surveillance activities. Virologic surveillance for measles is now well established in all of the WHO regions, and most countries have conducted at least some baseline surveillance. The WHO Global Genotype Database contains >7000 genotype reports, and the Measles Nucleotide Surveillance (MeaNS) contains >4000 entries. This sequence information has proven to be extremely useful for tracking global transmission patterns and for documenting the interruption of transmission in some countries. The future challenges will be to develop quality control programs for molecular methods and to continue to expand virologic surveillance activities in all regions.

Sequencing of the gene that encodes the capsid protein VP1 has been used as a surrogate for antigenic typing in order to distinguish enterovirus serotypes; three new serotypes were identified recently by this method. In this study, 14 enterovirus isolates from six countries were characterized as members of two new types within the species Human enterovirus B, based on sequencing of the complete capsid-encoding (P1) region. Isolates within each of these two types differed significantly from one another and from all other known enterovirus serotypes on the basis of sequences that encode either VP1 alone or the entire P1 region. Members of each type were ¢77?2 % identical to one another (89?5 % amino acid identity) in VP1, but members of the two different types differed from one another and from other enteroviruses by ¢31 % in nucleotide sequence (25 % amino acid sequence difference), indicating that the two groups represent separate new candidate enterovirus types. The complete P1 sequences differed from those of all other enterovirus serotypes by ¢31 % (26 % amino acid sequence difference), but were highly conserved within a serotype (<8 % amino acid sequence difference). Phylogenetic analyses demonstrated that isolates of the same serotype were monophyletic in both VP1 and the capsid as a whole, as shown previously for other enterovirus serotypes. This paper proposes that these 14 isolates should be classified as members of two new human enterovirus types, enteroviruses 74 and 75 (EV74 and EV75).

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SummaryIn 1995 and 1996, 4 persons from the Sultanate of Oman were confirmed with clinical Crimean-Congo haemorrhagic fever (CCHF). To assess the prevalence of CCHF virus infection in Oman, a convenience sample of imported and domestic animals from farms, abattoirs and livestock markets was examined by enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodies to CCHF virus. Ticks were collected from selected animals, identified, pooled by species, host and location and tested for evidence of infection with CCHF virus by antigen-capture ELISA. Serum samples from individuals working in animal and nonanimal contact-related jobs were also tested for CCHF antibodies. Serological evidence of infection was noted in 108 (22%) of 489 animals. Most of the ticks collected (618 of 912) from all species of sampled livestock were Hyalomma anatolicum anatolicum, a competent vector and reservoir of CCHF virus. 243 tick pools were tested for CCHF antigen, and 19 pools were positive. Of the individuals working in animal contact-related jobs, 73 (30.3%) of 241 non-Omani citizens and only 1 (2.4%) of 41 Omani citizens were CCHF antibody-positive. Butchers were more likely to have CCHF antibody than persons in other job categories. The presence of clinical disease and the serological results for animals and humans and infected Hyalomma ticks provide ample evidence of the presence of CCHF virus in yet another country in the Arabian Peninsula.keywords Crimean-Congo haemorrhagic fever, Hyalomma anatolicum,