Biology Reference
In-Depth Information
INTRODUCTION
Soil-transmitted helminthiasis (STH) represents a serious public health
problem (see Chapter 13) in countries where sanitation and hygienic
conditions are insufficient to respond to the needs of the population, and
where effective drugs for their treatment and public health control are
neither widely available nor affordable by those in need.
STH and socio-economic status are intimately linked. In countries
where an improvement in sanitation as a natural component of the
economic progress has taken place, a parallel progressive decline in the
relevance of STH has invariably been observed. Where universal or tar-
geted de-worming programs have accompanied such economic growth,
results have been obtained in a much shorter time span and they have
proven to be longer lasting. However, where chemotherapy has been
implemented periodically, even in the absence of improvements in sani-
tation and economic growth, important achievements have also been
obtained in terms of morbidity control.
STH control strategies should aim at controlling associated morbidity
in the first place, and at reducing STH transmission in those cases where
conditions permit a more comprehensive preventive effort. Different
combinations of the aforementioned approaches have been implemented
in endemic countries according to the local significance of the problem,
and to the availability of resources. Results obtained from ongoing control
programs in endemic areas are continuously monitored by the World
Health Organization (WHO) to refine existing strategies for the control
of STH.
THE E
XPERIENCE FROM JAPAN AND K
OREA
Japan has achieved successful and sustained control of STH and has
led the way in this effort.
By 1949, the nationwide fecal examination survey reported an overall
prevalence of 73.0% for intestinal nematodes: Ascaris lumbricoides (62.9%),
Trichuris trichiura (50%), and hookworms (3.5%). Non-governmental
organizations (NGOs) took the initiative, private laboratories were estab-
lished, stool examinations were carried out, and treatment with anthel-
mintic drugs (initially thiabendazole, then mebendazole and albendazole)
began. The intervention was organized as selective treatment in which
school children regularly underwent mass stool examination and positive
cases received treatment twice a year. In 1955, the Japan Association of
Parasite Control was founded and the government passed the School
Health Law in 1958 and issued guidance on control technologies. The
cellophane thick smear method (now described as the Kato-Katz
