Trends for influenza-related deaths during pandemic and epidemic seasons, Italy, 1969-2001.Age-specific patterns of death from influenza influenza or flu, acute, highly contagious disease caused by a virus; formerly known as the grippe. There are three types of the virus, designated A, B, and C, but only types A and B cause more serious contagious infections. vary, depending on whether the influenza season is epidemic or pandemic pandemic /pan·dem·ic/ (pan-dem´ik) 1. a widespread epidemic of a disease. 2. widely epidemic. pan·dem·ic adj. Epidemic over a wide geographic area. n. . We assessed age patterns and geographic trends in monthly influenza-related deaths in Italy from 1969 through 2001, focusing on differences between epidemic and pandemic seasons. We evaluated age-standardized excess deaths from pneumonia and influenza and from all causes, using a modified version of a cyclical cyclical Of or relating to a variable, such as housing starts, car sales, or the price of a certain stock, that is subject to regular or irregular up-and-down movements. Serfling model. Excess deaths were highest for elderly persons in all seasons except the influenza A influenza A n. Influenza caused by infection with a strain of influenza virus type A. influenza A Infectious disease An avian virus, especially of ducks–which in China live near the pig reservoir and 'vector'; (H3N2) pandemic season (1969-70), when rates were greater for younger persons, confirming a shift toward death of younger persons during pandemic seasons. When comparing northern, central, and southern Italy, we found a high level of synchrony synchrony /syn·chro·ny/ (-krah-ne) the occurrence of two events simultaneously or with a fixed time interval between them. atrioventricular (AV) synchrony in the amplitude of peaks of influenza-related deaths. ********** In Europe and the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. , the geographic pattern geographic pattern A general descriptor for lesions in which large areas of one color, histologic pattern, or radiologic density with variably scalloped borders sharply interface with another color, pattern or density, fancifully likened to national boundaries of influenza epidemics influenza epidemic caused 500,000 deaths in U.S. alone (1918–1919). [Am. Hist.: Van Doren, 403] See : Disease has been studied extensively, yet mostly at the national level with few local studies (1-6). Description of local influenza patterns can contribute to understanding of transmission and seasonality, which are influenced by factors such as demographic differences, climatic variability, and virus virulence Virulence The ability of a microorganism to cause disease. Virulence and pathogenicity are often used interchangeably, but virulence may also be used to indicate the degree of pathogenicity. . Age patterns and geographic trends for influenza are commonly assessed by using data on influenza-related deaths, which are indirectly quantified by using statistical methods to estimate seasonal increases in death from pneumonia and influenza (P&I) or all causes (AC) (7-11). This approach has shown that age-specific influenza death patterns vary according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. whether the influenza season is epidemic or pandemic. During epidemic seasons, proportion of influenza-related deaths is greatest among persons [greater than or equal to]65 years of age, whereas during all 3 influenza A pandemics in the 20th century, persons in this age group accounted for a lower proportion of influenza-related deaths in the United States (12) and Europe (8,13). Although patterns of influenza-related deaths have been investigated in many countries (14-18), few studies have focused on southern Europe Southern Europe or sometimes Mediterranean Europe is a region of the European continent. There is no clear definition of the term which can vary depending on whether geographic, cultural, linguistic or historical factors are taken into account. . With regard to Italy, these methods have been applied only to death data for elderly persons during 1970 2001 and only at the national level (19). Our objective was to use the above-described approach to assess age patterns and geographic trends for influenza-related deaths in Italy; our focus was on differences between epidemic and pandemic seasons. Methods Death and Population Data We obtained the monthly number of deaths caused by P&I and AC in Italy from 1969 (first available data year) through 2001 (most recent data year) from the Italian National Census Bureau Noun 1. Census Bureau - the bureau of the Commerce Department responsible for taking the census; provides demographic information and analyses about the population of the United States Bureau of the Census , which records all causes of death reported on death certificates and classifies them according to the International Classification of Diseases (ICD ICD International Classification of Diseases (of the World Health Organization); intrauterine contraceptive device. ICD abbr. ). For our analysis, we considered only the underlying cause of death. To select P&I deaths, we used ICD-8 codes 480-486 and 470-474 for the years 1969-1979 and ICD-9 codes The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. These codes are in the public domain. The geographic areas considered were the 3 administrative regions of Italy: northern Italy Northern Italy comprises of two areas belonging to NUTS level 1:
Piedmont (pēd`mŏnt), Ital. Piemonte, region (1991 pop. 4,302,565), 9,807 sq mi (25,400 sq km), NW Italy, bordering on France in the west and on Switzerland in the north. , Lombardy, Autonomous Province of Trento, Autonomous Province of Bolzano, Val d'Aosta Val d'Aosta is the name of two places:
 `lyä), former region, 3,356 sq mi (8,692 sq km), NE Italy, on the Adriatic Sea. , Liguria,
and Emilia Romagna. Central Italy comprises Tuscany, Umbria, Marche, and
Lazio. Southern Italy comprises Abruzzo, Molise, Campania, Puglia,
Basilicata, Calabria, Sicily, and Sardinia. For each year, we generated
summary datasets of the monthly number of deaths from P&I and AC,
stratified stratified /strat·i·fied/ (strat´i-fid) formed or arranged in layers. strat·i·fied adj. Arranged in the form of layers or strata. by age group (0-14, 15-44, 45~54, and [greater than or equal to] 65 years) (9). We calculated the annual number of persons in each age group and the monthly number of deaths per 100,000 population for each age group and standardized standardized pertaining to data that have been submitted to standardization procedures. standardized morbidity rate see morbidity rate. standardized mortality rate see mortality rate. these to 30.4-day months. Virologic Surveillance To determine which influenza viruses influenza virus n. Any of three viruses of the genus Influenzavirus designated type A, type B, and type C, that cause influenza and influenzalike infections. were circulating each season, we reviewed publications listing viral subtypes identified in Italian laboratories (21-23). For the most recent years (1999-2001), we obtained these data from the Italian National Influenza Center, which has performed virologic surveillance since 1999. Statistical Analyses To estimate age-specific excess deaths (an indirect measure of death attributable to influenza) from P&I and AC for the 32 influenza seasons, we applied a Serfling-type regression model to monthly time series of deaths (7,9). As described in previous studies (9,19), we removed the seasonal trend from the time-series data (de-trended) by fitting a smooth spline In computer graphics, a smooth curve that runs through a series of given points. The term is often used to refer to any curve, because long before computers, a spline was a flat, pliable strip of wood or metal that was bent into a desired shape for drawing curves on paper. See Bezier and B-spline. function to the average death rates in summer (June-August). Then, we applied a seasonal regression model to the de-trended series, excluding values for December-April, to model the expected mortality rates in the absence of influenza activity. Monthly mortality rates were calculated as the observed minus the predicted mortality rates for all epidemic months. We identified epidemic months by applying the above-mentioned procedure to deaths coded specifically as influenza (ICD-8 code 470-474 and ICD-9 code 487). We defined epidemic months as those winter months for which influenza-specific mortality rates exceeded the upper 95% confidence limit of the seasonal model. Seasonal excess deaths were estimated as the sum of monthly excess deaths, after back-adjusting for the true month length and removing the spline transformation. The model was applied to P&I and AC mortality rates separately for each age group. We achieved an excellent fit for all age groups. All model terms included were statistically significant (p<0.0001), but additional terms were not (p>0.05). Age Patterns and Geographic Trends To determine whether variations in age structure biased the geographic comparisons, we generated excess mortality rates for each area and age group and standardized them on the basis of the age distribution of the Italian population in 2001 (the year of the most recent Italian census). This permitted a comparison of age-adjusted P&I and AC excess mortality rate estimates across areas. To compensate for nondemographic differences among areas (e.g., differences in access to healthcare and in coding for cause-specific deaths) (24), we also calculated the percentage increase in mortality rates as the excess deaths divided by the baseline deaths in winter (expected deaths), for P&I and AC, separately. This measure has been used successfully in past research (7, 8). To estimate correlations of influenza-related death across the 3 geographic regions, we calculated the pairwise Spearman spear·man n. A man, especially a soldier, armed with a spear. correlation coefficients Correlation Coefficient A measure that determines the degree to which two variable's movements are associated. The correlation coefficient is calculated as: of seasonal estimates for the 32 years considered. Results Geographic Trends, Synchrony, and Effect of Epidemic Seasons (All Ages) For the 32 influenza seasons studied, excess deaths averaged 3 per 100,000 population (range 0-38) for P&I and 18 per 100,000 for AC (range 0-107). Influenza accounted for an estimated 57,243 deaths from P&I (average 1,789 per season) and 318,806 from AC (average 9,963 per season). The highest number of excess deaths was found for the 1969-70 pandemic season; no measurable number of excess deaths was found for 5 seasons (1981-82, 1984-85, 1986-87, 1990-91, 2000-01) (Figure 1). The 27 seasons that had excess P&I and AC deaths had an average of 2.4 epidemic months per season (range 1-4). The influenza seasons with higher excess deaths tended to be characterized by a predominance pre·dom·i·nance also pre·dom·i·nan·cy n. The state or quality of being predominant; preponderance. Noun 1. predominance - the state of being predominant over others predomination, prepotency of influenza A (H3N2) viruses (Figure 1). For these seasons, the average excess deaths from P&I and AC (4.5 and 23.4 per 100,000 population, respectively) was 4x higher than that for the 11 seasons in which influenza A (H1N1) or B viruses were predominant (0.8 for P&I and 7.4 for AC, per 100,000 population). [FIGURE 1 OMITTED] For the overall study period, the excess deaths per 100,000 population from AC was 15 for northern Italy, 14 for central Italy, and 22 for southern Italy; from P&I they were 4, 3, and 3, respectively (online Appendix Figure 1, available from www.cdc.gov/EID/content/13/5/ 694-appG1.htm). Also for these 32 years, no statistical differences among the 3 geographic areas were noted for excess deaths from P&I or AC (Kolmogorov-Smirnov test In statistics, the Kolmogorov–Smirnov test (often called the K-S test) is used to determine whether two underlying one-dimensional probability distributions differ, or whether an underlying probability distribution differs from a hypothesized distribution, in either , p = 0.8 and p = 0.9, respectively). Patterns were similar with the percent increase in excess deaths from P&I and AC. The 95% confidence intervals confidence interval, n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%. for estimates for individual seasons were within 6% of given values (Table 1). When conducting this analysis for seasons in which influenza A (H3N2), A (H1NI), and B predominated, area-level differences were again not significant. The strong correlation of excess-death estimates in the 3 regions suggests a high level of synchrony in the amplitude of local influenza epidemics (number of excess deaths peaked in the same month in each region) across Italy (P&I, Spearman [rho] = 0.88-0.93, p<0.0001; AC, Spearman [rho] = 0.80-0.93, p<0.0001) (Figure 2; online Appendix Figure 2, available from www.cdc. gov/EID/content/13/5/694-appG2.htm). [FIGURE 2 OMITTED] Magnitude and Trends of Influenza-related Deaths during Pandemic and Epidemic Seasons, by Age During epidemic seasons, most influenza-related deaths at the national level (84%) occurred in persons [greater than or equal to] 65 years of age, for P&I and AC; by contrast, during the 1969-70 influenza A (H3N2) pandemic season, deaths markedly affected all age groups, especially the 45-64 group. In Italy the proportion of excess deaths from AC in persons <65 years of age was 3-fold higher during the pandemic season than during all other epidemic seasons. In particular, when the pandemic season was compared with the season with the second highest number of deaths (1974-75), the number of influenza-related deaths was 7x higher for persons 0-14, 4x higher for persons 15-44 and 45-64, and 2x higher for persons [greater than or equal to] 65 years of age. Similar results were obtained for all 3 geographic areas (Table 2). The number of excess deaths from AC during the influenza A (H3N2) pandemic season was 1- to 9-fold higher in Italy than in other European countries (France, England, and Wales Wales, Welsh Cymru, western peninsula and political division (principality) of Great Britain (1991 pop. 2,798,200), 8,016 sq mi (20,761 sq km), west of England; politically united with England since 1536. The capital is Cardiff. ), in North American countries Noun 1. North American country - any country on the North American continent North American nation country, land, state - the territory occupied by a nation; "he returned to the land of his birth"; "he visited several European countries" (United States, Canada), and in Asian countries Noun 1. Asian country - any one of the nations occupying the Asian continent Asian nation country, land, state - the territory occupied by a nation; "he returned to the land of his birth"; "he visited several European countries" (Japan, Australia) (Table 3). Discussion This study showed a high level of correlation in the amplitude of influenza epidemics (i.e., peaks in rates were similar) in the 3 Italian regions during a 32-year period spanning epidemic and pandemic seasons. The analysis of local influenza-related death patterns did not show differences in mean mortality rates among geographic areas These findings are consistent with the high level of synchrony found in other area-level studies in Europe and in the United States (1,2,5,6). The first season analyzed was the 1969-70 pandemic season. In Italy, as in other European countries (8), the pandemic season was more destructive in the second season of circulation of influenza A (H3N2) virus (i.e., in 1969-70), 1 year after the pandemic strain was first introduced to Italy (25-27). The pandemic season seems to have had a greater effect in Italy; excess mortality rates were estimated to be 38 (20,000 deaths) for P&I and 107 (57,000 deaths) for AC. These unexpectedly large excess mortality rates were 3-fold higher than that in the United States and 1-fold higher than those in other European countries. The increase in percentage of deaths reduced but did not eliminate these differences. However, the percentage of deaths in persons <65 in Italy (29%) was lower than the percentage in that age group in the United States (34%) but similar to the percentages in other European countries, especially France (27%) (Table 3). Future studies could address these differences in numbers in numbered parts; as, a book published in numbers. See also: Number of deaths that may stem from underlying differences in baseline mortality rates or perhaps in influenza transmission. During the pandemic seasons, compared with epidemic seasons, the relative increase in mortality rates was lower for elderly than for younger persons in Italy, confirming that during pandemics, children and young adults have a greater relative risk for death than the elderly (12). A possible explanation is the partial immune protection of elderly persons who may have been exposed before 1891 to H3 antigens (28), whereas persons born after 1891 would not have been exposed to these antigens. Several limitations should be mentioned. First, deaths from P&I were not always confirmed by laboratory methods, which could have resulted in misclassification of deaths. However, patterns of death from P&I were very similar to those from AC, which are not subject to this bias. A second limitation was that demographic and nondemographic differences could have biased the geographic comparison. However, we performed age standardization standardization In industry, the development and application of standards that make it possible to manufacture a large volume of interchangeable parts. Standardization may focus on engineering standards, such as properties of materials, fits and tolerances, and drafting and calculated the percentage increase in deaths over the winter baseline, which reduces baseline differences in deaths, unrelated to influenza. A third, more critical, caveat stems from the surveillance of viral subtypes. The proportion of laboratory-confirmed cases has only been available since 1999 (i.e., for only 2 years of the study period). However, in the latest years the proportion of laboratory-confirmed cases was [approximately equal to] 15% (range 11%-28%), with >3,000 samples tested (29), which could have affected the accuracy of influenza diagnoses over time and perhaps across regions. For example, during the 1998-99 season, when influenza B influenza B n. Influenza caused by infection with influenza virus type B. influenza B Infectious disease An influenza virus which causes epidemics in 3-5 yr cycles. Cf Influenza A, Influenza C. viruses were predominant, the death rate was high compared with that found for the other influenza B seasons, which indicates that the characterization of viral subtypes is limited by the geographic distribution of the sites participating in virologic surveillance. Our findings suggest that influenza epidemics are strongly correlated in amplitude across the 3 regions of Italy. Different factors have been reported to drive the spatial and temporal correlations of epidemics: population movements and environmental factors such as climate or weather conditions (5,30,31). Although population movements are assumed to play a key role in the global spread of influenza epidemics, they have been quantified only in the United States (5, 32, 33). The role of environmental factors and differences in circulating viruses among the geographic areas in Italy also remains to be clarified. In conclusion, our results suggest that geographic synchrony of influenza in Italy is high and that for persons <65 years of age, death rates are likely to be substantially elevated in a future pandemic as compared with other epidemic seasons. Our study adds to others that have found strong spatiotemporal spa·ti·o·tem·po·ral adj. 1. Of, relating to, or existing in both space and time. 2. Of or relating to space-time. [Latin spatium, space + temporal1. patterns in illness and death from influenza in the United States, France, Australia, and across Europe (1,3,5,34). Such results provide insight for the Italian pandemic preparedness and response efforts (35,36) and could be used in mathematical models
Acknowledgments We thank Fabrizio Rossi for managing the dataset. The National Centre for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanita, Rome, Italy, provided support for C.R. References (1.) Bonabeau E, Toubiana L, Flahault A. The geographical spread of influenza. Proc Biol Sci. 1998;265:2421-5. (2.) Mugglin AS, Cressie N, Gemmell I. Hierarchical statistical modelling of influenza epidemic dynamics in space and time. Stat Med. 2002;21:2703-21. (3.) Viboud C, Boelle PY, Pakdaman K, Carrat F, Valleron AJ, Flahault A. Influenza epidemics in the United States, France, and Australia, 1972-1997. Emerg Infect Dis. 2004;10:32-9. (4.) Sakai T, Suzuki H, Sasaki A, Saito R, Tanabe N, Taniguchi K. Geographic and temporal trends in influenzalike illness, Japan, 1992-1999. Emerg Infect Dis. 2004;10:1822-6. (5.) Viboud C, Bjornstad ON, Smith DL, Simonsen L, Miller MA, Grenfell BT. Synchrony, waves, and spatial hierarchies in the spread of influenza. Science. 2006;312:447-51. (6.) Greene SK, Ionides EL, Wilson ML. Patterns of influenza-associated mortality among US elderly by geographic region and virus subtype (programming) subtype - If S is a subtype of T then an expression of type S may be used anywhere that one of type T can and an implicit type conversion will be applied to convert it to type T. , 1968-1998. Am J Epidemiol. 2006; 163:316-26. (7.) Serfling RE, Sherman IL, Houseworth WJ. Excess pneumonia-influenza mortality by age and sex in three major influenza A2 epidemics, United States, 1957-58, 1960 and 1963. Am J Epidemiol. 1967;86:433-41. (8.) Viboud C, Grais RF, Lafont BA, Miller MA, Simonsen L. Multinational impact of the 1968 Hong Kong influenza Hong Kong influenza n. Influenza caused by a serotype of influenza virus type A; it was first identified in Hong Kong during the 1968 epidemic. Also called Hong Kong flu. pandemic: evidence for a smoldering smol·der also smoul·der intr.v. smol·dered, smol·der·ing, smol·ders 1. To burn with little smoke and no flame. 2. pandemic. J Infect Dis. 2005; 192: 233-48. (9.) Simonsen L, Reichert TA, Viboud C, Blackwelder WC, Taylor RJ, Miller MA. Impact of influenza vaccination on seasonal mortality in the US elderly population. Arch intern intern /in·tern/ (in´tern) a medical graduate serving in a hospital preparatory to being licensed to practice medicine. in·tern or in·terne n. Med. 2005;165:265-72. (10.) Reichert TA, Simonsen L, Sharma A, Pardo SA, Fedson DS, Miller MA. Influenza and the winter increase in mortality in the United States, 1959 1999. Am J Epidemiol. 2004;160:492-502. (11.) Dushoff J, Plotkin JB, Viboud C, Earn DJ, Simonsen L. Mortality due to influenza in the United States--an annualized annualized Of or relating to a variable that has been mathematically converted to a yearly rate. Inflation and interest rates are generally annualized since it is on this basis that these two variables are ordinarily stated and compared. regression approach using multiple-cause mortality data. Am J Epidemiol. 2006;163:181-7. (12.) Simonsen L, Clarke MJ, Schonberger LB, Arden NH, Cox N J, Fukuda K. Pandemic versus epidemic influenza mortality: a pattern of changing age distribution. J Infect Dis. 1998;178:53-60. (13.) Stroup DF, Thacker SB, Herndon JL. Application of multiple time series analysis to the estimation of pneumonia and influenza mortality by age 1962-1983. Stat Med. 1988;7:1045-59. (14.) Lui KJ, Kendal AP. Impact of influenza epidemics on mortality in the United States from October 1972 to May 1985. Am J Public Health. 1987;77:712-6. (15.) Simonsen L, Clarke M J, Williamson GD, Stroup DF, Arden NH, Schonberger LB. The impact of influenza epidemics on mortality: introducing a severity index. Am J Public Health. 1997;87:1944-50. (16.) Fleming DM. The contribution of influenza to combined acute respiratory infections Noun 1. respiratory infection - any infection of the respiratory tract respiratory tract infection infection - the pathological state resulting from the invasion of the body by pathogenic microorganisms , hospital admissions, and deaths in winter. Commun Dis Public Health. 2000;3:32-8. (17.) Zucs P, Buchholz U, Haas W, Uphoff H. Influenza associated excess mortality in Germany, 1985 2001. Emerg Themes Epidemiol. 2005;2:6. (18.) Kyncl J, Prochazka B, Goddard NL, Havlickova M, Castkova J, Otavova M, et al. A study of excess mortality during influenza epidemics in the Czech Republic Czech Republic, Czech Česká Republika (2005 est. pop. 10,241,000), republic, 29,677 sq mi (78,864 sq km), central Europe. It is bordered by Slovakia on the east, Austria on the south, Germany on the west, and Poland on the north. , 1982-2000. Eur J Epidemiol. 2005;20:365-71. (19.) Rizzo C, Viboud C, Montomoli E, Simonsen L, Miller MA. Influenza-related mortality in the Italian elderly: no decline associated with increasing vaccination coverage. Vaccine. 2006;24:6468-75. (20.) Istituto Nazionale di Statistica Istituto Nazionale di Statistica (Istat) is the Italian national statistical institute. It was created in 1926 to collect and organize essential data about the nation. Administering the census is one of its activities. . Cause di morte, anno 2000. Annuario 16. 2004. (21.) World Health Organization. Weekly epidemiological record. Archives 1926~1995 [cited 2007 Mar 8]. Available from http://www. who.int/wer/archives/en/ (22.) Mancini G, Arangio-Ruiz G, Campitelli L, Castrucci MR, Diana L, Donatelli I, et al. Surveillance of influenza A and B viruses in Italy between 1984 and 1987. Eur J Epidemiol. 1988;4:445-50. (23.) Mancini G. Arangio-Ruiz G, Donatelli I, Rozera C, Butto S. Diffusion of influenza viruses in Italy in years 1982-83-84. Laboratory investigations at the National Influenza Centre of WHO. Ann Ist (company) IST - Imperial Software Technology. Super Sanita. 1986;22:717-21. (24.) Langmuir AD, Housworth J. A critical evaluation of influenza surveillance. Bull World Health Organ. 1969;41:393-8. (25.) Rocchi G, Ragona G, de Felici A, Muzzi A. Epidemiological evaluation of influenza in Italy. Bull World Health Organ. 1974;50:401-6. (26.) Rocchi G, Muzzi A, Giannini V. Sero-epidemiological studies of the adult population at the time of an epidemic caused by A2 influenza virus (Hong Kong Hong Kong (hŏng kŏng), Mandarin Xianggang, special administrative region of China, formerly a British crown colony (2005 est. pop. 6,899,000), land area 422 sq mi (1,092 sq km), adjacent to Guangdong prov. variant) which occurred in Rome in the winter of 1969-1970 [in Italian]. Nuovi Ann Ig Microbiol. 1970;21:150-60. (27.) Colonnello F. The epidemic of A2 Hong-Kong 68 virus influenza in Italy [in Italian]. G Mal Infett Parassit. 1969;21:893-5. (28.) Simonsen L, Reichert TA, Miller MA. The virtues of antigenic sin: consequences of pandemic recycling on influenza-associated mortality. New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of : Elsevier Science B.B. International Congress Series; 2004 p. 791-4. (29.) Bella A., De Mei B., Giannitelli S., Rota M.C., Salmaso S., Donatelli I, et al. FLU- Istituto Superiore di Sanita: a sentinel sentinel /sen·ti·nel/ (sen´ti-n'l) one who gives a warning or indicates danger. sentinel a recording mechanism, such as an animal, a farm or a veterinarian, posted explicitly to record a possible occurrence or series of surveillance network for influenza relying on general practitioners general practitioner n. Abbr. GP A physician whose practice consists of providing ongoing care covering a variety of medical problems in patients of all ages, often including referral to appropriate specialists. and pediatricians. Report for 2004-2005 [in Italian]. The Institute; 2005. Report no. 22. (30.) Kendall BE, Bjornstad ON, Bascompte J, Keitt TH, Fagan WF. Dispersal dis·per·sal n. The act or process of dispersing or the condition of being dispersed; distribution. Noun 1. dispersal , environmental correlation, and spatial synchrony in population dynamics Population dynamics is the study of marginal and long-term changes in the numbers, individual weights and age composition of individuals in one or several populations, and biological and environmental processes influencing those changes. . Am Nat. 2000; 155:628-36. (31.) Bjorustad ON, Ims RA, Lambin X. Spatial population dynamics: analyzing patterns and processes of population synchrony. Trends Ecol Evol. 1999;14:427-32. (32.) Brownstein JS, Wolfe C J, Mandl KD. Empirical evidence for the effect of airline travel on inter-regional influenza spread in the United States. PLoS Med. 2006;3 :e401. (33.) Cox NJ, Subbarao K. Global epidemiology of influenza: past and present. Annu Rev Med. 2000;51:407-21. (34.) Saito R, Paget J, Hitaka S, Sakai T, Sasaki A, van der Velde K, et al. Geographic mapping method shows potential for mapping influenza activity in Europe. Euro Surveill. 2005;10:E051027. (35.) Ministry of Health. National plan for preparedness and response to an influenza pandemic
(36.) Ciofi degli Atti ML. Rizzo C, Pompa MG, Salmaso S, Greco D. How prepared is Europe for pandemic influenza? Lancet. 2006;368:25. Dr Rizzo is a physician with the National Centre of Epidemiology and Health Promotion, Istituto Superiore di Sanita, Rome, Italy. Her research interests focus on epidemiology and surveillance of infectious diseases infectious diseases: see communicable diseases. , especially modeling of influenza epidemics and pandemics over time. Address for correspondence: Caterina Rizzo, Istituto Superiore di Sanith, CNESPS, Infectious Disease Infectious disease A pathological condition spread among biological species. Infectious diseases, although varied in their effects, are always associated with viruses, bacteria, fungi, protozoa, multicellular parasites and aberrant proteins known as prions. Unit Viale Regina Elena, 299 Rome 00169 Italy; email: caterina.rizzo@iss.it Caterina Rizzo, * ([dagger]) Antonino Bella, * Cecile Viboud, ([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) Lone Simonsen, ([double dagger]) Mark A. Miller, ([double dagger]) Maria Cristina Rota, * Stefania Salmaso, * and Maria Luisa Maria Luisa may refer to:
* Istituto Superiore di Sanita, Rome, Italy; ([dagger]) University of Bari Organization These are the 12 faculties in which the university is divided into:
Table 1. Mean age-standardized excess all-cause deaths per 100,000
population and the winter seasonal percent increase attributable to
influenza, Italy, 1969-2001 *
Deaths Northern Central Southern
Pandemic season (1969-1970)
Excess 103.6 85.3 105.2
Percent increase 21.7 21.0 25.9
Epidemic seasons (1970-2001)
Excess 13.7 13.2 17.1
Percent increase 3.4 3.6 5.1
Entire study period (1969-2001)
Excess 16.6 15.4 19.9
Percent increase 4.0 4.1 5.7
* 95% confidence intervals for individual season estimates were
within 6% of values listed.
Table 2. Mean age-standardized excess deaths per 100,000 population,
Italy, 1969-2001
Pneumonia and influenza
1969-70
Age, y Northern Central Southern
0-14 2.4 3.3 7.8
15-44 3.8 2.5 3.0
45-64 38.8 25.4 27.4
[greater than 288.7 221.8 218.2
or equal to]65
Total 43.0 31.5 29.3
Pneumonia and influenza
1970-2001
Age, y Northern Central Southern
0-14 0.0 0.1 0.1
15-44 0.1 0.1 0.1
45-64 0.7 0.4 0.7
[greater than 14.0 12.7 14.2
or equal to]65
Total 2.2 1.9 1.9
All causes
1969-70
Age, y Northern Central Southern
0-14 8.6 8.7 30.3
15-44 7.7 7.0 8.4
45-64 112.1 75.1 109.0
[greater than 694.8 621.6 859.2
or equal to]65
Total 103.6 85.3 105.2
All causes
1970-2001
Age, y Northern Central Southern
0-14 0.3 0.6 1.6
15-44 0.6 0.8 0.8
45-64 4.3 4.3 6.6
[greater than 75.6 71.2 115.7
or equal to]65
Total 12.0 11.6 18.6
Table 3. Multinational comparison of influenza A (H3N2) Hong Kong
pandemic, based on all-cause excess deaths estimates *
England,
Italy Wales France
Deaths ([dagger]) ([dagger])
Overall no./100,000 population 107 77 72
Increases over baseline, % 24 20 21
Persons <65 y, 29 23 27
Australia
([double Japan
Deaths dagger]) ([dagger])
Overall no./100,000 population 64 49
Increases over baseline, % 16 20
Persons <65 y, 20 N/A
USA Canada
Deaths ([section]) ([section])
Overall no./100,000 population 27 12
Increases over baseline, % 8 6
Persons <65 y, 34 24
* Data from this study and (8). Estimates are for the major pandemic
seasons, for which timing varied by country. N/A, not applicable.
([dagger]) Second season of virus circulation, 1969-70.
([double dagger]) Second season of virus circulation, 1970.
([section]) First season of virus circulation, 1968-69.
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