Isolation of adenovirus type 7 during 1995-1999 and a case of type 7h infection - Hiroshima City
(IASR 2000; 21:27-28)

Adenovirus type 7 was not isolated in Hiroshima City before 1994. The first isolate was in May 1995, from a one year old girl, who was diagnosed acute bronchitis and otitis media. Until June 1998, the virus was isolated from 127 individuals. Peak of these incidences in Hiroshima City was seen in July 1995, and the trend lasted until 1996. The second smaller peak was observed during 1997 to 1998. However, the virus was not isolated during July 1998 to July 1999, while adenovirus type 3 was isolated remarkably during the same period of time. Recently, three adenovirus type 7 isolates are identified in August, October, and November, 1999 (Figure).

In Hiroshima city, approximately 78% of the adenovirus type 7 isolates is collected from patients with respiratory diseases (Table 1). Twenty-seven isolates were collected from one year old patients, followed by 19 isolates from 2 years old and 3 years old respectively. About 55% of the isolates are from children under 3 years old. Seventy-five (about 60%) isolates were from male patients, and 51 were from females.

According to Wadell's classification using Bam HI enzyme fragment pattern, at least 14 patterns are reported for adenovirus type 7 isolates. Hashido et al. reported detection of a new gene fragment pattern at the 47^th meeting of the Japanese Society of Virology. These study results conclude that the isolates in Japan collected during 1987 to 1992 are identical with the 7d type isolate, which is dominant in China. Those isolates can be distinguished from the isolates collected in Japan after 1995 by Bst EII enzyme pattern. Because the isolates after 1995 is identical as the 7d2 type Azar et al. reported from Israel, we complied with these results in Table 2.

Analysis of the type 7 from Hiroshima City during 1997 to 1999, using the restriction enzymes revealed that most of the isolates showed the same pattern. But one strain collected in 1997 presented the 7a pattern by Bst EII and a new pattern by Pst I. Another strain presented the d1 pattern by Bcl I. One strain collected in 1998 developed a new pattern by Bst EII. These isolates are classified as subtypes of 7d, such as 7dv1, 7dv2, 7dv3, respectively (Table 2). In August 1999, an individual yielded 3 strains, and they presented the 7h pattern by Bam HI, which was reported from Aichi and Kanagawa Prefecture. Restriction analysis using Bst EII, Hpa I, and Sac I presented the 7a type, Hind III, Sma I, Pvu II, and Bgl II presented the 7d type, and Pst I, Bgl I, and Bcl I presented a new pattern. A 27 year old female yielded this 7h strain, and she was diagnosed as influenza-like illness with fever unknown origin. Major clinical symptoms included fever (39.9C), cough, diarrhea, lymph node swelling. Comparing with those of the d2 type, symptoms seem severer. Clinical record does not clarify her travel history.

Trends of the 7h strain should be carefully observed.

Reported by Yoshihumi Ikeda, Katsuhiko Abe, Mayumi Kamimura, Akito Fujii, Koji Yamaoka, and Takeo Ogino, Hiroshima City Public Health Institute.

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