H—3l

The next table shows the incidence of cases in the months November to March, by types of district:—

Table VIII.—Incidence of Positive Cases in City, Urban, Semi-rural, and Country Districts

The ratios for " rural districts " probably err On tlie low side, as the population figure upon which they were based includes a large number of districts from which no cases were reported. Similarly, the " semi-rural" ratios are probably too high, as the areas drawn upon are not completely covered by the population figures quoted. These two combined (4 and 5 in Table VIII) give an incidence of 61-6 per 100,000. This relatively high incidence in the rural population has been noted again and again in many parts of the world. An unusual feature in this epidemic is, however, the fact that the percentage of cases amongst persons aged 15 years or more is loiver in the rural and semi-rural districts than in the city and its environs. This is the reverse of the usual finding. (b) Ratio of " Suspect " Illnesses to Positive Cases Our test populations were deliberately selected in the near vicinity of positive cases. The controls were in parts of the urban area remote from the main incidence, and no positive cases occurred within their ambit. By averaging these suspect illnesses we get a fair picture of the whole area. In Table IX this average incidence per 10,000 in each age/sex group has been compared with the incidence of positive cases, and the ratio of suspect to positive illnesses is shown :

Table IX. —Ratio of Suspect Illnesses to Positive Cases, November to February Inclusive

80

— Population, 1st April, 1947 (Estimated). Positive Cases November to March. Ratio of Cases to Population. Cases per 100,000. Percentage of Cases Aged 15 Years and Over. 1. Auckland Metropolitan Area, less North Shore 2. North Shore boroughs 3. Otahuhu and Papatoetoe 4. Other urban* (semi-rural) districts 5. Rural districts 236,000 29,660 11,570 14,950 54,860 90 4 4 20 23 1: 2,622 1: 7,415 1: 2,892 1 : 747 1:2,385 38-1 13-5 34-6 133-8 41-9 26-7 25 25 20 17-4 Total 347,040 141 1:2,461 40-6 24-1 * The following districts have been excluded : Howick, Great Barrier Island, Waiheke, Warkworth, and Helensville.

Sex. Age. Suspect Illnesses per 10,000. Positive Cases per 10,000. Ratio Suspect Positive Cases. Round Figures. Males 1015 and over 1,920 2,155 1,595 710 17-.2 21-7 5-0 1-3 112: 1 99: 1 319: 1 546: 1 1 children : Ratio, 130 : 1. J Males over 15 years: Ratio, 500: 1. Females 05— 1015 and over 1,460 1,630 1,290 875 7-2 71 7-7 0-9 203:1 230: 1 168: 1 972:1 1 children : Ratio, 200 : 1. J Females over 15 years : Ratio, 1,000: 1. Total •• 991 3-29 301: 1 Ratio, 300 : 1.