HELMINTHS IN SLUDGE BIOSOLIDS
Worms (helminths) include nematodes, cestodes, and trematodes
When EPA published this list of worms in sludge/biosolids in 1989, it did not indicate any of the worms could
cause fatal infections. In fact it would appear the EPA experts did not know Trichuris and Ascariasi were two
different types of worms.
Occurrence of Pathogens in Distribution and Marketing Municipal Sludges (1988)
EPA Pathogen list from Part 503 (1989)
15. Necator americanus ------------------------------- Hookworms,
16. Taenia sp ------------------------------------------ Taeniasis (Tapeworm)
17. Toxicara ------------------------------------------- Visceral larva migrans
18. Trichuris sp-------------------------------------- Ascariasis
Intestinal nematodes of importance to man are Ascaris lumbricoides (roundworm), Trichinella spiralis
(trichinosis), Trichuris trichiura (whipworm), Enterobius vermicularis (pinworm), Strongyloides stercoralis
(Cochin-china diarrhea), Ancylostoma duodenale and Necator americanes (hookworms) and Dracunculus
medinensis (fiery serpents of the Israelites). E. vermicularis and T. trichiura are exclusively intestinal
parasites. Other helminths listed above have both intestinal and tissue phases.
Trichuris trichiura, or the whipworm buries its thin, threadlike anterior half into the intestinal mucosa and feeds on tissue
secretions, not blood. This relative tissue invasion causes occasional eosinophilia. The cecum and colon are the most
commonly infected sites.
rural Southeast, where 2.2 million people are infected. Whipworm infection is rarely fatal. Rectal prolapse may occur in
heavily infected hosts. Clinical symptoms are limited to patients with heavy infection, who tend to be small children or
others who eat a lot of dirt.
Nocturnal loose stools, Dysentery can occur in patients with greater than 200 worms. Rectal prolapse, Failure to thrive,
Symptoms of anemia (massive infection only), Vague abdominal discomfort, Stunted growth, Mild abdominal tenderness
Signs of anemia, Rectal prolapse http://www.emedicine.com/emerg/topic842.htm
19. Hymenolepis nana ----------------------------- Taeniasis
Hymenolepis nana, The Dwarf Tapeworm
The Hymenolepis nana is also known as the Dwarf Tapeworm. There are 400 species of Hymenolepis. It is the
Hymenolepis nana that is known as the Human Tapeworm. Beetles and fleas are the intermediate hosts (the tapeworm
does not always need this host), and humans are both the primary and definitive hosts and can reinfect themselves.
Once the eggs are ingested they hatch, go through their larval stage in the small intestine, and then move into the
tissue in the gut and grow to adulthood. Hymenolepis nana infestations are prevalent in highly populated areas where
hygiene and sanitary conditions are poor.
Symptoms of the Hymenolepis nana are: anorexia, abdominal pain, and diarrhea, however, symptoms often go
Hymenolepis nana, -- Infection is most common in the Southeast (1% of school children in 1 study) and among
institutionalized children. Among more than 200,000 stool specimens submitted to the state laboratories in 1987 for ova
and parasite analysis, 0.4% were positive for H nana. Because most infections do not produce symptoms, the true
incidence is likely considerably higher.
The vast majority of infections produce no symptoms. Symptom frequency seems to correlate with increasing worm
burden. Among children with clinical infection, symptoms (in order of decreasing frequency) include restlessness,
irritability, diarrhea, abdominal pain, restless sleep, anal pruritus, and nasal pruritus. Rare symptoms include anorexia,
increased appetite, vomiting, nausea, bloody diarrhea, hives, extremity pain, headache, dizziness, behavioral
disturbances, and seizures
Taeniasis is a tapeworm infection
Teniasis; Pork tapeworm; Beef tapeworm; Tapeworm; Taenia saginata; Taenia solium
Tapeworm infestation does not usually cause any symptoms. Infection is generally recognized when the infected
person passes segments of proglottids in the stool, especially if the segment is moving.
self-infection with tapeworm eggs -- cysticercosis (T. solium only), which may cause seizures
rarely, worms may cause obstruction of the intestine
Taeniasis. Infection often is asymptomatic; however, mild gastrointestinal tract symptoms, such as nausea, diarrhea,
and pain, can occur. Tapeworm segments can be seen migrating from the anus or feces.
Cysticercosis. Manifestations depend on the location and numbers of pork tapeworm cysts (cysticerci) and the host
response. Cysts may be found anywhere in the body. The most common and serious manifestations are caused by
those in the central nervous system. Cysts of Taenia solium in the brain (neurocysticercosis) can cause seizures,
behavioral disturbances, obstructive hydrocephalus, and other neurologic signs and symptoms. Neurocysticercosis can
be a leading cause of epilepsy, depending on epidemiologic circumstances. The host reaction to degenerating cysts
can produce signs and symptoms of meningitis. Cysts in the spinal column can cause gait disturbance, pain, or
transverse myelitis. Subcutaneous cysts produce palpable nodules, and ocular involvement can cause visual
Produces only mild abdominal symptoms. Occasionally appendicitis or cholangitis can result from migrating proglottids.
Risk of development of cysticerosis with Taenia solium.
(Yanko 1988) Trichuris and Ascaris, Toxocara, Hymenolepis and Taenia (ascariasis was
estimated to affect four million people in the United States.)
Humans unknowingly consume microscopic and small macroscopic animals with their food. The intestinal tract is
inhospitable to most of these organisms, which are either digested or evacuated in the feces. However, some obligate
or facultative parasites may become established in the human body. Although a number of parasites produce no
symptoms and are not associated with disease, others may cause mild, moderate, or severely acute illness and even
permanent damage. CAUTION: Pathogens that are easily disseminated may be contained in samples and will be
liberated by digestion. Of special concern are macroscopic tapeworm cysts and microscopic cysts of protozoa. When
the presence of such pathogens is suspected, carry out the digestion and subsequent sample handling in a negative
pressure hood until the suspect digest is placed in a safely closed dish. Handle all utensils as if contaminated, and
autoclave or incinerate after use.
II. Nematodes Worms (helminths) include nematodes, cestodes, and trematodes. Nematodes are non-segmented
roundworms, and the majority are free-living in the soil or water. While there are billions of nematodes that live in the
soil, most (about 99%) are non-parasitic. Caenorhabditis elegans is the best known example of a nematode, free-living
in soil. C. elegans is an ideal animal for genetics research, and its genome has been sequenced – it has 19,080 genes.
Parasites have many more genes than their free-living counterparts because they need a wider biological arsenal to
keep your immune system at bay. They live in strange places – your kidney, your lung, your brain, muscle tissue, and
gut tract. All parasitic nematodes are transmitted by living close to the ground – by putting dirt in your mouth or by just
stepping on the ground with your bare feet. Everybody poops and everybody eats, and parasitic nematodes take
advantage of this, utilizing feces to transmit disease. In many parts of the world, fecally-contaminated water is sprayed
onto vegetables as fertilizer. The vegetables are washed in contaminated water before being sold on the market. Raw
produce has the potential to transmit environment-resistant stages of parasites (cooked, frozen, or peeled produce is
generally safe). This may present a problem to us only when we travel to certain parts of the world, however, these
parasites represent background infection for the 4 billion people today who harbor at least one species of parasitic
nematode. While our immune system has methods to fight parasitic helminths, namely the eosinophil reaction (see
Figure 1, courtesy of Dave Anthony), many of today’s parasites have developed ways to evade the immune response.
Moving on to our first parasitic nematode. . .