Explanation and implications of increasing trend of villages with only one case of guineaworm for guineaworm eradication in India
Kaul, S.M.
Journal of Communicable Diseases 24(4): 211-218
1992
ISSN/ISBN: 0019-5138 PMID: 1344955 Document Number: 404135
Under the Guineaworm Eradication Programme (GWEP) in India, active case search data are consolidated in the lists of year-wise guineaworm affected villages, first prepared in 1985. These lists contain valuable information on many parameters of guineaworm eradication in India. Among other things, they show that in a given year there is always a proportion of villages with only one case relative to the total number of infected villages, and this proportion seems to increase with the progress of the eradication programme. The proportion for seven years between 1986 and 1992 in nineteen districts chosen for analysis was observed to be 22.2, 26.6, 35.0, 38.0, 40.0, 46.7, and 55.8 per cent. Correlation coefficient (gamma) for nineteen districts as a whole was found to be 57 significant at 0.05 level. It is argued that this observation can be explained on the assumption that the single case in a village originates from any of numerous extradomestic unsafe water sources, in agricultural fields, which because of their great multiplicity lie outside the purview of the control measures. When guineaworm disease is widespread and at a high intensity transmission level, the existence of such foci is masked under the main village foci as during active case searches a distinction as to the origin of guineaworm cases cannot be made. Extra domestic foci become increasingly manifest as the main village foci disappear under impact of control measures. Thus, increase in the proportion of such villages could be used as a crude indicator of the successful implementation of the GWEP. The analysis of district data shows that guineaworm disappears when the proportion of such one case village reaches a high level. It is further argued that guineaworm will be eliminated in most of the districts of India in a year or two, but may still persist in Dhar, Nagaur, Jodhpur and Bijapur where a thorough appraisal of the present distribution of guineaworm and the eradication programme is indicated.