Israel Medical Association Journal

Background: Each winter influenza activity is a major cause of morbidity and mortality both in Israel and worldwide.

Objectives: To identify the influenza viruses active in Israel during the winter season and to assess the extent of influenza morbidity.

Methods: Information was collected on a population of 18,684 individuals enrolled in two community clinics in central Israel. It included the total number of visits for acute respiratory infection – including influenza and influenza-like illness (ARI/flu-like) – during a 20 week surveillance period (23 November 1997 to 27 March 1998) and the percent of influenza virus isolates in nasopharyngeal specimens from a sample of patients with ARI/flu-like collected on a weekly basis during the same period.

Results: A total of 5,947 visits for ARI/flu-like were recorded among 18,684 enrolled patients in two community clinics (18.1%). The progressive increase in the number of visits for ARI/flu-like reached a peak on week 2/98 with 597 visits and a rate of 31.95 visits per 1,000 population. After this, a decrease to the initial values was evident by week 12/98. Most affected patients were in the age groups 5–14 and 65 years and over, with a rate of 733.5 and 605.3 visits per 1,000 population, respectively. Influenza virus was isolated from 92 of the 426 nasopharyngeal specimens (21.6%). The most commonly detected strain was A/Sydney/5/97(H₃N₂) like (77.2%). The peak rate of isolates was recorded at the beginning of January (01/98).

Conclusions: A/Sydney/5/97(H₃N₂) like-strain was the dominant influenza virus. Its presence did not prevent the simultaneous activity of influenza A/H₁N₁ virus. The dynamic of the clinical disease as expressed by the weekly visit rate for ARI/flu-like was similar to the temporal pattern of the virological findings. The extent of morbidity suggests moderate epidemic activity.
 

Background: Previous studies have documented an increased incidence of cardiac mortality and sudden death during winter months.

Objectives: To evaluate seasonal variation in sudden death in a hot climate such as the desert region of southern Israel.

Methods: We analyzed the files of 243 consecutive patients treated for out-of-hospital sudden death by the Beer Sheva Mobile Intensive Care Unit during 1989-90. Daily, monthly and seasonal incidence of sudden death was correlated with meteorological data, including temperature, heat stress, relative humidity and barometric pressure.

Results: The seasonal distribution of sudden death was 23% in spring, 21% in summer, 25% in autumn and 31% in winter (not significant). In patients with known heart disease there were more episodes of sudden death in cold weather (<15.4°C) than hot (>34.2°C) (16 vs. 3, P<0.05). Resuscitation was less successful in cold compared with hot weather (28 vs. 11, P<0.05). Of patients older than 65 years, 11 sustained sudden death when heat stress was below 12.4°C compared to 2 patients when heat stress was above 27.5°C (P=0.05).

Conclusion: Despite the warm desert climate, there were more cases of sudden death in older patients and in those with known heart disease during the winter season and on particularly cold days.