1921
Volume 3, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645
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Abstract

Summary

Under the auspices of the Ludlow Jute Co., Ltd., an investigation into the epidemiology and local significance of malaria was conducted at the company's jute mill in India from August, 1951, through July, 1952. This mill is located on the banks of the tidal Hooghly River, 17 miles south of Calcutta, and employs 6,000–7,000 workers half of whom (together with dependents) are quartered within the mill compound, the remainder residing in nearby villages. Dwellings within the Ludlow compound have been sprayed with DDT thrice yearly since 1948; an immediately adjacent mill (Gagalbhai) and the nearly villages served as nonprotected reference areas for the study.

Two spleen and blood-smear surveys among children at the mills and in the villages revealed a low incidence of malaria, although a focal outbreak was uncovered at Gagalbhai where the spleen index rose to nearly 15 per cent and the parasite index to 58 per cent; at Ludlow and in the villages, however, both indices remained well below 5 per cent.

Regular mosquito catches (in the two mill areas and in 10 villages) disclosed 13 species of anophelines. predominated in catches from human dwellings during the height of the malaria season (October–November), accounting for as much as 40 per cent of the total house catch. Naturally infected were taken during October–December and again in February and a natural infection rate of 0.76 per cent was established for the year; no other species of anopheline was found naturally infected. Mean-unit mosquito catches from Ludlow dwellings were 15 times lower than those from Gagalbhai and 30 times lower than those from the villages. Only rare specimens of were taken in Ludlow compound dwellings while outside the compound the mosquito was found in focal concentrations.

The malaria season of 1951–1952 was a comparatively severe one locally. At Ludlow during November the malaria rate based on medical leaves issued reached 84 per 1,000; however, at Gagalbhai the rate was very nearly double that for the same period. Malaria rates were also lower among Ludlow compound residents as compared with village-resident Ludlow employees.

The economic significance of malaria at Ludlow may be judged from the following data: during the year 3,408 leaves were issued for malaria (19.0 per cent of all medical leaves) and these resulted in a loss of 7,173 man-days (12.9 per cent of all time lost to illness). In November, the peak malaria month, 33.5 per cent of the medical leaves issued and 24.6 per cent of the days lost were attributable to malaria.

The epidemiology of local malaria is described and the merits and shortcomings of current control operations are discussed.

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/content/journals/10.4269/ajtmh.1954.3.74
1954-01-01
2017-11-18
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