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Journal of Clinical Microbiology, April 2007, p. 1308-1309, Vol. 45, No. 4
0095-1137/07/$08.00+0 doi:10.1128/JCM.00010-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Molecular Epidemiology of Astrovirus Infection in Infants in Wuhan, China
Man-Qing Liu,1*
Bei-Fang Yang,1
Jin-Song Peng,1
Dun-Jin Zhou,1
Li Tang,1
Bin Wang,1
Yu Liu,2
Shi-Hong Sun,2 and
Wen-Zhe Ho1
Wuhan Centers for Disease Prevention and Control,1
Wuhan Children's Hospital, Wuhan 430022, Hubei, China2
Received 3 January 2007/
Returned for modification 1 February 2007/
Accepted 5 February 2007

ABSTRACT
We report the molecular epidemiology of astrovirus infection
in 335 infants with diarrhea in Wuhan City, China. Astrovirus
RNA was detected in the stool specimens of 33 children (9.87%).
Genotyping analysis indicated that 23 out of 24 astroviruses
identified were classified as belonging to genotype 1, with
highest identity (>98%) to a Mongolian strain.

TEXT
Diarrhea is a major cause of childhood morbidity and mortality,
especially in developing countries (
2). Human astrovirus may
be the second most common cause of viral gastroenteritis in
young children, with rotavirus being the first (
6-
8,
14). Human
astrovirus infections occur worldwide and have been detected
in people at different ages, but mostly in children and the
elderly (
7). The incidence of astrovirus infection ranges from
about 2 to 9% in children with gastroenteritis in both developing
and developed countries (
3-
5,
11,
13,
15), although some studies
have reported that the infection rate may be as high as 26%
(
10). In order to investigate the role of astrovirus infection
in childhood diarrhea in Wuhan City, China, we examined astrovirus
RNA in the fecal specimens of 335 infants (under the age of
3 years) from the outpatient department of Wuhan Children's
Hospital between June 2004 and May 2005.
Among 335 stool specimens examined, 33 were positive for astrovirus RNA as determined by reverse transcription-PCR with the primer set Mon340/Mon348 (Invitrogen, Shanghai, China) that permits detection of all eight serotypes of human astroviruses (1). The infection rate (9.87%) of our study is in agreement with that reported in other parts of China (9) and other developing countries (5). There was no significant difference (P = 0.23) in the infection rates between boys (11.44%, 23/201) and girls (7.46%, 10/134). As demonstrated in Fig. 1A, the incidence in the winter and spring months (November 2004 to April 2005) was significantly higher (P < 0.05) than that in the summer and autumn months (June to October 2004 and May 2005). December was the month with the highest incidence of astrovirus infection (41.67%, 10/24). This seasonal pattern of astrovirus infection in Wuhan City is consistent with other epidemiological studies of temperate regions (7) and is similar to that seen in patients with rotavirus infection. The children of 24 to 29 months of age appeared to have the highest infection rate (40%, 4/10) (Fig. 1 B). However, since there were only 10 specimens collected from this age group, the significance of this finding remains to be determined.
Twenty-four specimens positive for astrovirus RNA were genotyped
by sequencing a 449-bp region of ORF2 of the astroviruses as
previously described by Noel et al. (
12). Reverse transcription-PCR
was performed with the primer set Mon269/Mon270, which was considered
to be more universal than the Mon244/Mon245 set (
12). The purified
DNA was sequenced by Shanghai Sangon Biological Engineering
& Technology and Service Co., Ltd., with an ABI3730 automatic
sequencer. Each nucleotide sequence of the 348-bp region was
compared to that of each reference strain by using the BLAST
program (National Center for Biotechnology Information); the
comparison showed that 23 out of 24 viruses were classified
as genotype 1 viruses, while only 1 was identified as genotype
3. Genotype 1 has been considered the most frequent and dominant
type in most parts of the world, with a few exceptions (
16).
Because the analysis of astrovirus genes from different regions of the world is useful for developing detection kits and a vaccine for astrovirus infection, we used MegAlign in the DNAStar program to determine the sequence identities of the Wuhan astroviruses to those from different areas in the world. The majority (87.5%, 21/24) of the astroviruses identified in this study showed very little or almost no divergence among themselves. Twenty-one of these genotype 1 viruses showed the highest identity (96.8 to 98.6%) to a Mongolian strain (GenBank accession number AY590261) and lesser identities to strains from Australia (AY175258; ca. 94.0 to 95.7%), India (AB241064; ca. 93.4 to 95.1%), Argentina (AY324859; ca. 90.8 to 92.6%), Brazil (DQ381480; ca. 89.4 to 91.1%), and Colombia (DQ157438; ca. 88.5 to 90.3%) (Fig. 1C). The remaining two strains (accession numbers DQ788596 and DQ788612) of the 23 genotype 1 astroviruses had high identity (97.7%) to a Brazilian strain (DQ381480).
Our data clearly indicate that astrovirus as an etiological agent has a significant role in infant gastroenteritis in Wuhan City. Since the majority of the astroviruses identified in the infants in Wuhan are classified as belonging to one genotype (type 1), it would be feasible to develop an effective vaccine against type 1 astrovirus infection in the Wuhan area. Further studies are needed to understand the nature of astrovirus infection and to provide strategies for the prevention and control of astrovirus infection in children in China.
Nucleotide sequence accession numbers.
The nucleotide sequences of the 348-bp regions of the 24 astroviruses have been submitted to GenBank under the following accession numbers: DQ788590 to DQ788612 and DQ630763.

FOOTNOTES
* Corresponding author. Mailing address: Wuhan Centers for Disease Prevention and Control, 24 Jiang Han Bei Road, Wuhan, Hubei 430022, People's Republic of China. Phone: 86-27-59512765. Fax: 86-27-59512768. E-mail:
liumq33{at}hotmail.com 
Published ahead of print on 14 February 2007. 

REFERENCES
1 - Belliot, G., H. Laveran, and S. S. Monroe. 1997. Detection and genetic differentiation of human astroviruses: phylogenetic grouping varies by coding region. Arch. Virol. 142:1323-1334.[CrossRef][Medline]
2 - Bern, C., J. Martines, I. de Zoysa, and R. I. Glass. 1992. The magnitude of the global problem of diarrhoeal disease: a ten-year update. Bull. W. H. O. 70:705-714.[Medline]
3 - Bon, F., P. Fascia, M. Dauvergne, D. Tenenbaum, H. Planson, A. M. Petion, P. Pothier, and E. Kohli. 1999. Prevalence of group A rotavirus, human calicivirus, astrovirus, and adenovirus type 40 and 41 infections among children with acute gastroenteritis in Dijon, France. J. Clin. Microbiol. 37:3055-3058.[Abstract/Free Full Text]
4 - Foley, B., J. O'Mahony, S. M. Morgan, C. Hill, and J. G. Morgan. 2000. Detection of sporadic cases of Norwalk-like virus (NLV) and astrovirus infection in a single Irish hospital from 1996 to 1998. J. Clin. Virol. 17:109-117.[CrossRef][Medline]
5 - Gaggero, A., M. O'Ryan, J. S. Noel, R. I. Glass, S. S. Monroe, N. Mamani, V. Prado, and L. F. Avendano. 1998. Prevalence of astrovirus infection among Chilean children with acute gastroenteritis. J. Clin. Microbiol. 36:3691-3693.[Abstract/Free Full Text]
6 - Glass, R. I., J. Noel, D. Mitchell, J. E. Herrmann, N. R. Blacklow, L. K. Pickering, P. Dennehy, G. Ruiz-Palacios, M. L. de Guerrero, and S. S. Monroe. 1996. The changing epidemiology of astrovirus-associated gastroenteritis: a review. Arch. Virol. Suppl. 12:287-300.[Medline]
7 - Guix, S., S. Caballero, C. Villena, R. Bartolome, C. Latorre, N. Rabella, M. Simo, A. Bosch, and R. M. Pinto. 2002. Molecular epidemiology of astrovirus infection in Barcelona, Spain. J. Clin. Microbiol. 40:133-139.[Abstract/Free Full Text]
8 - Herrmann, J. E., D. N. Taylor, P. Echeverria, and N. R. Blacklow. 1991. Astroviruses as a cause of gastroenteritis in children. N. Engl. J. Med. 324:1757-1760.[Abstract]
9 - Liu, C. Y., K. L. Shen, S. X. Wang, Y. Y. Liu, and G. T. Zhaori. 2004. Astrovirus infection in young children with diarrhea hospitalized at Beijing Children's Hospital. Chin. Med. J. (Engl. Ed.). 117:353-356.
10 - Maldonado, Y., M. Cantwell, M. Old, D. Hill, M. L. Sanchez, L. Logan, F. Millan-Velasco, J. L. Valdespino, J. Sepulveda, and S. Matsui. 1998. Population-based prevalence of symptomatic and asymptomatic astrovirus infection in rural Mayan infants. J. Infect. Dis. 178:334-339.[Medline]
11 - Mustafa, H., E. A. Palombo, and R. F. Bishop. 2000. Epidemiology of astrovirus infection in young children hospitalized with acute gastroenteritis in Melbourne, Australia, over a period of four consecutive years, 1995 to 1998. J. Clin. Microbiol. 38:1058-1062.[Abstract/Free Full Text]
12 - Noel, J. S., T. W. Lee, J. B. Kurtz, R. I. Glass, and S. S. Monroe. 1995. Typing of human astroviruses from clinical isolates by enzyme immunoassay and nucleotide sequencing. J. Clin. Microbiol. 33:797-801.[Abstract]
13 - Svenungsson, B., A. Lagergren, E. Ekwall, B. Evengard, K. O. Hedlund, A. Karnell, S. Lofdahl, L. Svensson, and A. Weintraub. 2000. Enteropathogens in adult patients with diarrhea and healthy control subjects: a 1-year prospective study in a Swedish clinic for infectious diseases. Clin. Infect. Dis. 30:770-778.[CrossRef][Medline]
14 - Ulloa, J. C., A. Matiz, L. Lareo, and M. F. Gutierrez. 2005. Molecular analysis of a 348 base-pair segment of open reading frame 2 of human astrovirus. A characterization of Colombian isolates. In Silico Biol. 5:537-546.[Medline]
15 - Walter, J. E., and D. K. Mitchell. 2000. Role of astroviruses in childhood diarrhea. Curr. Opin. Pediatr. 12:275-279.[CrossRef][Medline]
16 - Walter, J. E., D. K. Mitchell, M. L. Guerrero, T. Berke, D. O. Matson, S. S. Monroe, L. K. Pickering, and G. Ruiz-Palacios. 2001. Molecular epidemiology of human astrovirus diarrhea among children from a periurban community of Mexico City. J. Infect. Dis. 183:681-686.[CrossRef][Medline]
Journal of Clinical Microbiology, April 2007, p. 1308-1309, Vol. 45, No. 4
0095-1137/07/$08.00+0 doi:10.1128/JCM.00010-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.