Genetic analysis of Asian measles virus strains – new endemic genotype in Nepal

Different genotypes of C1, D3, D5, and H1 were isolated in outbreaks of 1984, 1987-1988, 1991-1993, and 2001, respectively, when the previous circulating genotype was replaced successively by a new genotype, through molecular studies of measles since 1984 in Japan. In March 2007, several patients with measles were observed in outpatient clinics, who were all young adolescents in high school and university students. The outbreak expanded subsequently throughout Japanese districts in May and is still ongoing in 2008. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) was used to detect the measles genome from 18 clinical samples obtained from patients suspected of modified measles infection with a very mild febrile illness. The measles genome was detected in nine patients by reverse transcription polymerase chain reaction (RT-PCR) and in 12 patients by RT-LAMP. Six measles strains were isolated in the 2007-2008 outbreak and identified as the D5 genotype (MVi/Bangkok.THA/93 type) different from the D5 sub-cluster (MVi/Palau.BLA/93 type) isolated in 1990-2005. Similar Bangkok type D5 strains were isolated in Phnom Penh in 2002 and in Taiwan in 2003, suggesting that the D5 strains might have been introduced via South East Asia, rather than resulting from the accumulation of mutations in the D5 strains of 1990-2005. One D9 strain was isolated from a sporadic case in Aichi in 2006. There was no difference in the antigenicity of the D9 and D5 strains in comparison with the vaccine strain. Infrastructure of systematic laboratory-based surveillance system should be established in order to confirm measles virus infection in Japan.

Section: Discussionmentioning

confidence: 99%

Modified adult measles in outbreaks in Japan, 2007–2008

Nagai¹,

Xin

Yoshida

et al. 2009

“…The uptake of MMR 1 , has been as low as 69% in the fourth quarter of 2001, rising in recent years to 88%, however never exceeding 90% at a national level. Previously in Ireland only the genotype D2 MeV has been described, which was originally identified in South African isolates [EPI, 1998;Coughlan et al, 2002] [Truong et al, 2001] and these original Nepalese isolates had four genotype D8-specific mutations (I406T, K441R, Y451N, and A459L) [Truong et al, 2001] [Kremer et al, 2008]. In 2005, a 17-year-old unvaccinated girl who was incubating measles returned to the US from Romania and attended a social event on her return, creating the largest documented outbreak of measles in the United States since 1996 [Parker et al, 2006] [Siedler et al, 2006].…”

Section: Discussionmentioning

confidence: 99%

Molecular epidemiology of circulating measles virus in Ireland 2002–2007

Carr

Conway

Waters

et al. 2008

The molecular characterization of measles virus (MeV) is a valuable epidemiological tool to monitor virus transmission and to discriminate between imported and endemic infection. There has been significant immigration into Ireland in recent years and many individuals originate from regions of high measles incidence. Ireland has had a number of outbreaks of MeV which appear attributable to sub‐optimal vaccine uptake and possibly imported strains as new genotypes have been identified in recent years. To ascertain any significant changes in circulating measles genotypes we investigated 65 confirmed measles cases between the years 2002 and 2007. The laboratory diagnosis of measles was confirmed by detection of measles‐specific IgM in oral fluid in conjunction with a real‐time polymerase chain reaction assay targeting the MeV hemagglutinin gene. Phylogenetic analysis based on the 3′ hypervariable region of the nucleoprotein gene was performed and three genotypes, all within measles clade D, were found to be circulating during this time period. In 2002 and 2003, genotype D8 (n = 2) was observed whereas genotype D7 was dominant in 2003 (n = 31). A distinct change in the circulating MeV genotype and increased genetic diversity was observed between 2004 and 2007. All cases were within genotype D4 (n = 32) but were phylogenetically distinct from each other. These data provide important epidemiologic baseline information on MeV in Ireland and facilitates detailed examination of measles transmission. J. Med. Virol. 81:125–129, 2009. © 2008 Wiley‐Liss, Inc.

“…Virologic surveillance conducted in other parts of the world had identified genotype D4 in association with imported measles cases that had a recent travel history in India and Pakistan WHO, 2001a]. Genotype D4 is also circulating in Pakistan, Nepal, and East Africa Truong et al, 1999Truong et al, , 2001Nigatu et al, 2001].…”

mentioning

confidence: 99%

Characterization of measles sequences from Pune, India

Wairagkar

Rota

Liffick

et al. 2002

The goal of this study was to conduct the initial genetic characterization wild-type measles viruses currently circulating in India. Reverse transcription-polymerase chain reaction detected measles RNA in 11 of 14 throat swabs collected from sporadic and outbreak-associated cases in the city of Pune, during 1996-1998. Sequence analysis of the H and N genes showed that six sequences were genotype D4, three were genotype D8, and two were genotype A. Continued virologic surveillance in other areas of India as well as neighboring countries will indicate the extent of genetic diversity present among wild-type measles viruses circulating in India.