Emergence of human rotavirus genotype G9 in metropolitan Detroit between 2007 and 2009

Abstract

, rotavirus (RV)-positive stool samples from 238 children with acute gastroenteritis, seen at Children's Hospital of Michigan in Detroit, USA, were collected and RV genotyping was performed. G and P genotypes were determined by RT-PCR and nucleotide sequencing was conducted on selected G9 and P[6] strains. Correlation between the severity of gastroenteritis episode and the infecting G genotype was done using a 14-point scoring system. The predominant G genotype was G9 (39.5 %), followed by G1 (35.3 %) and G4 (15.5 %), while P[8] was the most prevalent P genotype (66.5 %), followed by P[4] (21.9 %) and P[6] (11.2 %). The gene combinations G1P [8] and G9P[8] were the most prevalent (21.4 % and 20.6 %, respectively), followed by G4P[8] (13 %) and G9P [6] (8.8 %). Immunization data showed that only 17/238 (7.1 %) children received ¢one dose of RV vaccine (the pentavalent vaccine RotaTeq or the monovalent vaccine Rotarix) and that 10/17 were infected with G4P[8] strains. Severity of RV gastroenteritis episodes was not related to the infecting G genotype. Our results suggest a high proportion of genotype G9 strains in combination with P[8], P[6] and P[4] specificity circulating in the metropolitan Detroit area. While the protective efficacy of the RV vaccines has been demonstrated against G9P[8] strains, the level of cross-protection offered by the vaccines against G9 strains with P[6] and P[4] genotypes in the Detroit paediatric population remains to be determined. INTRODUCTIONRotavirus (RV) is a major cause of acute gastroenteritis worldwide. It accounts for approximately 40 % of diarrhoea hospitalizations in children ,5 years of age (Parashar et al., 2006). An estimated 527 000 RV-infected children younger than 5 years die each year, the majority in developing countries (Parashar et al., 2003). Control of RV disease is most likely to be achieved through widespread use of an effective vaccine.The outer layer of group A RV is composed of two proteins, VP4 and the VP7, which are encoded by RNA segment 9 and 4, respectively (Estes & Kapikian, 2007). Rotaviruses are classified into G and P types based on the reactivity of the outer capsid proteins, VP7 and VP4, with serotype-specific monoclonal antibodies or on the amplification of PCR amplicons using genotype-specific primers. Genotype P[8] is the most common P type globally, followed by P[4] and P[6]. P[8] tends to be more frequently associated with serotypes G1, G3 and G4, while P[4] is more likely to be associated with serotype G2. Prior to 1990, the most common serotypes globally were G1P[8], G2P[4], G3P [8] and G4P[8]; since then, G9P [8] has been recognized as the fifth most globally common type (Gentsch et al., 1992(Gentsch et al., , 2009Koshimura et al., 2000). The G and P type specific antibodies, particularly those to the G antigen, are believed to play an important role in protection against RV gastroenteritis (Gentsch et al., 2005). This prompted the development of vaccines based on the most common circulating strains in target populations at the time: G1...

Full genome analysis of rotavirus G9P[8] strains identified in acute gastroenteritis cases reveals genetic diversity: Pune, western India

“…13,[16][17][18][19] Variable prevalence rates of G9 RVA strains have been also reported between 27% and 62% among geographical areas like Cuba, France, Mexico, and USA where G9 RVs strains have emerged. [20][21][22] Circulation of these G9 RVA strains in different lineages and sublineages has also been reported earlier. 23 These RVA G9P [8] strains have been under circulation and found to cause symptomatic infections among children <5 years of age, who were expected to be protected by the pre-existing immunity which would provide heterotypic protection against common genotypes.…”

“…Ever since 1995, rapid spread of G9 RVA has been reported worldwide making them now the major human RVA genotype . Variable prevalence rates of G9 RVA strains have been also reported between 27% and 62% among geographical areas like Cuba, France, Mexico, and USA where G9 RVs strains have emerged . Circulation of these G9 RVA strains in different lineages and sublineages has also been reported earlier .…”

Emergence of rotavirus G9 in 2012, as the dominant genotype in Turkish children with diarrhea, in a university hospital in Ankara

“…It remains unclear whether widespread implementation of RV vaccines causes the emergence of non-vaccine genotypes. Recent regional epidemiological studies have confirmed the high prevalence of the genotype G9, reaching 50%-90% in some circumstances (25). RV genotype diversity, especially that of G9 and G12, is a great challenge for current vaccination programs (11).…”

Diversity of Rotavirus Strain Circulated in Gwangju, Republic of Korea

“…The first G9 strain, WI91, was detected in children in the United States in 1983 [22] and was first detected in 2002 in South Korea [14] . G9 has become recognized as one of the emerging genotypes in many countries such as Cuba [23] , France [24] , Mexico [25] , the United States [26] , and Libya [27] . In this study, G9s were the third most identified genotype and had a slightly greater predominance over G3 and G4.…”