INVESTIGATION OF PARASITES IN SOUTHERN DOMESTIC WASTE
SLUDGE: A POSSIBLE INDUSTRIAL POINT SOURCE
D. Blair Leftwich, Research Assistant
R. S. Reimers, Associate Professor
A. J. Englande, Jr., Associate Professor
M. D. Little, Professor
D. D. Bowman, Research Assistant
School of Public Health and Tropical Medicine
Tulane University
New Orleans, Louisiana 70112
INTRODUCTION
There has been minimal concern over the presence of parasites in domestic waste in
the U.S. However, for many countries utilizing land application, parasites in sewage
have posed very serious endemic health problems. This is partly due to the concentrating effect on parasites from recycling domestic waste sludges. Many documented
cases of parasite transmission to animals from contact with raw and treated domestic
waste sludges exist. Current emphasis is on reuse of treated domestic sewage sludge;
hence, based on the ultimate disposal method practiced, human exposure to potentially
infectious waste may be significantly increased. During the past five years, much research concerning the public health problems of domestic waste has been effected;
but these investigations have been concerned with pathogenic microbes, enteric viruses,
heavy metals and toxic chemicals. There is a scarcity of information concerning parasites in domestic waste and treatment thereof.
This chapter deals with the evaluation of 27 waste treatment plants over a 5-state
area in the South for persistence of parasites in waste sludges. This study was conducted over a period of one year with sampling during each season. Results represent
a preliminary step in evaluating the possible risk to human and animal health due to
utilization of domestic sewage sludges. Correlation of results is made between the incidence of parasites in sludges and industrial contribution, with particular emphasis on
waste from abattoirs.
LITERATURE REVIEW
Although the incidence  of human infection with intestinal parasites has generaUy
declined in this country during the past few decades, in some locations, mostly in the
South, infections with Ascaris lumbricoides and Trichuris trichiura are highly endemic
[1]. Also, in cities (including some northern cities) that have had an influx of immigrants from areas of the world where intestinal parasites are stdl very common (Puerto
Rico, Mexico, Viet Nam, etc.), significant numbers of infected individuals may be
found [2]. In addition, a recent report from the Center for Disease Control [3] indicates that significant numbers of human infections with Ascaris lumbricoides and Trichuris trichiura were reported in 1976 by State Health Department Laboratories in
several northern states. In addition to the eggs and cysts of the parasites of humans that
enter municipal sewage systems, those of certain animal parasites (especially the eggs of
Ascaris suum, Toxocara canis, Toxocara cati, Trichuris vulpis and Trichuris suis) are also
known to persist in municipal sewage sludges. The sources of these eggs are probably
residential sewage, industrial input (meat packing plants, abattoirs, etc.) and surface water
runoff. Several of these animal parasites are capable of causing disease in humans [4].
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