Kazuyo Yamashita

Surveillance of Viral Gastroenteritis in Japan: Pediatric Cases and Outbreak Incidents

Abstract Surveillance results from pediatric cases and outbreaks of viral gastroenteritis in Japan are presented. In winter, both small round structured virus (SRSV, or Norwalk-like viruses) and rotavirus were detected from infants with gastroenteritis; however, in recent years, the prevailing time of SRSV infection has preceded that of rotavirus infection. Most nonbacterial gastroenteritis outbreaks were related to SRSV infection, and >60% of the outbreaks were caused by contaminated food. In small-sized outbreaks, raw oysters were the primary source of transmission. In large-sized outbreaks, school lunches and catered meals that were served at schools, banquet halls, and hospitals were most often implicated in the transmission of foodborne gastroenteritis.

Influenza surveillance system of Japan and acute encephalitis and encephalopathy in the influenza season

Abstract Aim: To understand the situation of influenza epidemics and neurologic complications during the influenza season in Japan.

EPIDEMICS OF ASEPTIC MENINGITIS DUE TO ECHOVIRUS 30 IN JAPAN

Two rages of epidemic of aseptic meningitis (AM) due to echovirus 30 (E30) in Japan were analyzed with respect to two sources of information, AM incidence and E30 isolation, both gathered through the National Epidemiological Surveillance of Infectious Diseases. The first E30 epidemic spread throughout Japan in 1983 and ceased within the year. The second epidemic, starting in 1989, continued for the three successive years, and in the last year, 1991, the total E30 reports numbered 4,061, the largest number of a single virus type ever reported. Although the epidemic showed temporal and geographical shift and lasted for one or two years in some areas, most laboratories reported the largest number of E30 isolation in 1991. Among E30-yielding cases with clinical information during 1982-1992, the associating frequency with AM was as high as 82.5%. Other central nervous system involvements such as encephalitis, myelitis, encephalomyelitis and/or paralysis were reported in 36 E30-yielding cases and their monthly and age distributions were different from those of AM cases. The proportion of such disease among E30-yielding cases (0.60%) was close to that of other enteroviruses (0.56%). During the epidemics, E30 was isolated more frequently from cerebrospinal fluid than was E4 or E9 which prevailed coincidentally. E30 was most frequently isolated from cases of 4-7 years of age, sharing the common characteristic pattern of age distribution with other enteroviral meningitis. E30-yielding cases, however, involved a large number of older age groups than those of other enterovirus infections, and this tendency was the most pronounced in the first epidemic year, 1983. The contribution of these E30 epidemics on the yearly trend of clinically reported AM incidence and on the shift of its age distribution was also analyzed.

HERPANGINA SURVEILLANCE IN JAPAN, 1982-1989

Abstract In Japan, herpangina cases increase every summer with an incidence peak in July. During the past eight years from January, 1982 to December, 1989, a total of 3,974 viruses from herpangina cases were reported from 47 participating laboratories, and coxsackie A (CA) viruses accounted for most of them, 3,055 (76.9%). The major types associated with herpangina were, in order of frequency, CA4, 10, 5, 6, 2 and 3, representing 87.2%-80.8% of total isolations reported for each respective type in this period. Eighty-four point four percent of the total virus isolations were from children at four years of age or younger. More than 80% of total CA virus isolations were from nasopharyngeal specimens and nearly 90% of the viruses were isolated in mice.