Schistomiasis

ByProfessor Mohamed Shalaby
Professor and Former Chairman of the Urology Department 
Assiout University

Schistosomiasis, presently know as bilharziasis to credit Theodor Bilharz the discoverer of the parasite, dates back to antiquity. Its evolutionary origin most likely stems from the Great Lakes region of East Africa, the hypothesized cradle of man’s ancestors . The host and the parasite had over the years become well adapted to each other under environmental conditions ideally suited for the transmission of the parasite. However under natural conditions of the past, severe widespread infections were unusual considering the nomadic nature of man’s life at that time. The ancient Egyptians, through settling and cultivating the Nile Valley, were among the first to contract the disease in an endemic manner. They recognized the disease four to five thousand years ago and mentioned it in medical papyri as well as depicted it in engravings on the walls of temples . Recently, it was confirmed by direct demonstration of the eggs of the parasite in the tissues of mummies through paleopathologic studies.

Information From Medical Papyri

The disease was first recorded in the oldest papyrus of kahun(1900B.C.). It was named “a-a-a” disease, the hieroglyphic script. The phallus was used as a symbol to represent the concept of hematuria. To the ancient Egyptian physicians, the urinary schistosomiasis , we may assume that it refers to this disease.

Etiology

A casual relationship to a verminous parasite is reported in Ebers Papyrus (1550 B.C), prescription 62(6,10), of which a reproduction of its hieroglyphic script, transliteration and English translation , it characterizes the disease (hematuria), causative parasite (worm in belly), some herb therapy (chams and rosseuisou) and a comment on its intractability; “ they are not killed by any remedy”. It is interesting that the ancient Egyptian is antiquity knew the same facts that we know at present.

The disease was known to the Ancient Egyptian to be waterborne. This is supported by three documented historical events, namely: avoiding polluted waters, wearing of penile sheath and circumcision.

1-NEGATIVE CONFESSIONS. The Ancient Egyptians believed in an after-life world and presumed that the resurrected would be judged on the doomsday according to his commitments during his first earthy life. He would be deserving the paradise of the second life, if he denied having done bad deeds. These negative confessions are noted in their scared book, “Book of the dead”, wish reads in Chapter 125: “ I have not waded water”.

2-WEARING OF PENILE SHEATH. It is known of Ancient Egyptians to cover their external genitalia. This covering was done in various ways, one of them was case-sheath covering the penis. Although wore for other reasons, it was common among peasants, fishermen, boatmen, potters and papyri carriers i.e. those who were professionally connected with Nile water and mud. Pfister, a Swiss urologist who spent a long time in Egypt, bilharziasis , which so often manifested itself in the canal.

3-CIRCUMCISION. Allen reported that circumcision was performed by the Ancient Egyptians to rid the individual of his preputal sac, which was thought to act as a reservoir for the parasite and thus perpetuates the infestation. Although it was a wrong belief that the parasite ascended through the urethra, yet circumcision this way, emphasized the water-borne concept of the disease. It may be interesting to note that circumcision started as a sign of nobility , royalty and priesthood in the old and middle kingdom. Later, possibly with the belief of its preventive role against bilharziasis, circumcision became universal among other classes.

The disease was mentioned 50 times in the medical papyri, namely: 28 times in Ebers, 12 times in Hearst, 9 times in Berlin and once in London papyri. These frequent mentions are take to indicate “ endemicity”. In addition, there were frequent references to its prevalence in agricultural communities. Because of this presumed endemicity, a great concern was attached to it, possibly consitituting a national health problem, not unlike our present state of affairs.

Clinical Presentation

The clinical features of the disease as described in medical papyri are presented mental weakness referred to in the papyrus possibly represent a picture of chronic anemia Engravings of Egyptian patients with abdominal swelling, umbilical hernia and scrotal swelling are displayed at the tombs of Ptah-Hetep and Ankh-ma-hor in Saqqara. These probably represent the late manifestation of bilharzial hepatic fibrosis with ascitis.

Treatment

In ancient Egypt, there was a general belief that all sickness and disease came from without and were mainly due to the action of evil spirits. Hence, medicine at that time was essentially a mixture of religion and magic, dispensed as a sacrifices and incantations to expel evil spirits. However, a beginning of a scientific treatment such as surgical procedures and administration of drugs was documented in medical papyri. Egypt was famous among early civilizations for its medicinal prescriptions, some of which are still in current use in our pharmacopoeia.

In case of schistosomiasis, although considered as an intractable disease, the Ancient Egyptians described a variety of drugs for its treatment. These included palliative drugs such as sedatives, antispasmodics, narcotics and colonic evacuants. However the use of the Ancients Egyptians of a specific drug, namely: antimony, which is among our present day therapies for bilharziasis, is really spectacular. They also made a pioneer step in the prevention of this disease by discouraging people to get in contact with polluted waters.

 

Papyrus references for drug treatment of Schistosomiasis

1.Ammi-visnaga & hyocyamus (Ebers:173,230,331 Berlin:115)

2.Junipar and Beer (Ebers:137)

3.Pomegranate roots in beer (Ebers:63)

4.Natron:Sodium mono-and bicarbonate (Ebers:171)

5.Hemp (Ebers:59)

6.Dried Carb (Ebers:226,228)

7.Balanties (Ebers:229)

8.Rush nuts and Valeriana (Ebers:168)

9.Barley, dates and honey (Ebers:62,63)

10.Castor oil, figs

11.Stibum:antimony sulphide (Hearts:83)

 

Artistic Depiction

It is customary of the popular artist of Ancient Egypt to document life incidentds and activities in extreme details, whether in the form of statues, steles, engravings or paintings. His theme, believing in a second after life world and in resurrection, was to depict the external appearance including disease states features. This makes it easier for the sole to recognize the original body, and feel at home in the old envelope.

In connection with bilharziasis, the picture of penile sheath, the engravings of circumcision and the engravings abdominal swelling, umbilical hernia and scrotal hypertrophy are but few examples of these depictions related to the disease.

 

Paleopathology

Paleopathology studies have provided the direct evidence that schistosomiasis did occur in the Nile Valley during pharaonic era. Pathologic studies of mummified tissues were first introduced by the French Scientist Fouquet and continued by G. Elliot Smith and F. Wook Jones. The real and serious studies were carried out in 1910 by Sir A. Ruffer. It included for the first time the results of histologic examination of mummified tissues, rendered swollen to their former size and flexibility. Of the histopathologic findings, he reported on the presence of calcified S.heamatobium eggs among the convoluted tubules of the kidneys of two mummies from the 20th Dynasty (1250-1000 B.C.).

 

Egg of S.heamatobium found in the colon of a mummy of a teenage Egyptian boy who lived in Thebes around 1200 B.C. There was also involvement of the urinary bladder and liver ( by courtesy of Dr. T.A. Reyman, AFIP Pathology of Tropical and Extraordinary Disease.

The Relation To Cancer

It may be relevant to the subject of this monograph, to inquire about the Ancient Egyptian knowledge of tumors of the urinary bladder and possible relation to bilharziasis. Their knowledge could be presumed, as they knew of the bladder as an anatomic organ, and they knew about cancer as a disease. Further suggestive evidence is also available from some medical papyri and paleopathologic studies.

Genitournary Schistosomiasis

A.General Considerations

1. Caused by a blood fluke (parasite trematode worm), this disease was first recognized by Egyptian physicians of the 12th dynasty (1900 ac). In 1851, Theodor Bilharz first described the worms in the human mesenteric venous plexus and linked them to the disease.

2.Approcimately 200 million humans are infested with schistosomes, namely Schistosoma mansoni, Schistosoma japonicum, and Schistosoma haematobium. In the United States, there are more than 400,000 people living with the disease. Incidence of urinary involvement is 40-60%.

3. GU Schistosoma is primarily caused by S. haematobium. It is endemic in Africa and certain areas of the Middle East such as Southern Iraq.

4.S.mansoni and S.japonium cause intestinal tract and liver disease.

B.Etiology and Life Cycle

1.Adult schistosomes are delicate cylindrical worms, 1-2 cm in length, They have adapted for existence in venules and have a mean life span of 3.4 years. A single pair spawns from 25,000-600,000 eggs in their lifetime.

2.Humans are infected through contact with infested fresh water in small canals, ditches, or drains. The infective larval stage, free swimming cercariae, penetrates the skin or mucous membranes

3.Cercariae (shed by the snails in fresh water sources) penetrate through unbroken human skin and reach the general circulation and are pumped by heart throughout the body. Only worms that reach the portal circulation survive.

4.Adult worms reaching their definitive destination in the venous plexi mature and mate. Females lay eggs(200-500 per day) in the submucosa of the involved tissues: the bladder, lower ureters, and seminal vesicles in the case of GU schistosomiasis. Eggs are extremely antigenic and produce an intense inflammatory reaction in the tissues where they are deposited. About 20% erode through the viscera of deposition (intestine, bladder) and are eliminated.

5.Ova are eliminated in human feces and urine. If they reach fresh water, they start their asexual cycle(snail) resulting in the production of sporocyst. They hatch, and the contained larvae, ciliated miracidia, find a specific freshwater snail that they penetrate. There they form sporocysts that ultimately form the cercariae that leave the snail and pass into the freshwater to begin their sexual cycle after reaching their human hosts.

C. Pathogenesis and Clinical Features

1. Stage 1: Generalization or incubation period.

a) Young schistosomes rapidly acquire host-derived-antigenic materials on their body surface and become immunologically camouflaged.

b) Secretions and excretions of the worms may engender hypersensitive and general manifestations of illness.

c) Allergic skin reactions, cough, fever, malaise, body and bone aches, and gastrointestinal (GI) symptoms may be present.

2. Stage 2: Deposition of ova by mature worms in the target area.

a) Because female worms may lay eggs for years, the disease is slowly progressive.

b) Toxic and antigenic products of a viable miracidium pass through the shell of the egg and elicit a granulomatous inflammatory response around the egg, forming pseudotubercles.

c) General symptoms include “swimmers itch” and Katayama syndrome fever, lethargy and myalgia).

Acute symptoms generally occur 3-9 weeks after infection

d) GU symptoms include painful terminal hematuria, dysuria and pyuria, hematospermia and vesical irritability.

3.Stage 3: Late complications.

a) End result of repeated, chronic infections.

b) Infection of urinary tract—usually coliform organisms

(E. coli, Klebsiella, Pseudomonas). Definitive association with Salmonella typhi and Salmonella paratyphi infections.

c) Schistosomal bladder polyps, secondary infection, stones, urinary tract calcification.

d) Fibrosis is the ultimate result of infection and may involve the bladder, urethra, and ureters, leading to hydronephotic renal atrophy and bladder contraction. Schistosomal “contracted bladder” syndrome occurs late in the course of the disease and presents as constant, deep lower abdominal and pelvic pain, urgency, both diurnal and nocturnal frequency, and incontinence.

e) Bilharzial bladder cancer syndrome has an early onset (40-50 years of age) and results in squamous cell carcinoma (60-90%) and adenocarcinoma (5-15%).

More than 40% of squamous cell carcinomas are exophytic and carry a good prognosis.

D. Diagnosis.

1. Diagnosis of infection

a) Urine sediment reveals elliptical terminally spined eggs of S.haematobium. The highest yield may be obtained at mid-day. Sending the patient on a short walk before urine collection may facilitate shedding of eggs from the bladder mucosa. Number of eggs per 10 mL of urine has the best sensitivity and specificity of all estimates of intensity and for current infection.

b) Rectal or bladder mucosal biopsy may also be performed to look for eggs.

c) Serologic tests such as enzyme linked immunosorbent assay (ELISA) and immunoblot are very sensitive and specific. However, positive results do not always correlate with the worm burden and do not help distinguish between previous exposure and current infection or reinfections.

2. Diagnosis of sequelae and complications.

a) Plain x-ray of abdomen classically reveals bladder calcification. Seminal vesicle, urethral and distal ureteral calcifications may be seen.

b) IVU is essential to look for obstructive uropathy. CT scanning and ultrasound may be employed for the detection of obstructive and destructive lesions.

c) Cystoscopy may be used to obtain mucosal biopsies for original diagnosis and is also utilized to asses for complications such as bladder cancer.

E. Therapy

1. Medical management.

a) S.haematobium is sensitive to two oral drugs: praziquantel (Biltricide) and oxamniquine.

b) Praziquantel, a heterocycline prazinoisoquinoline, is the drug of choice for treatment of all species. Dosage for S.haematobium is 20mg/kg by mouth every 6-8 hours times 3 doses, given with food. IT reliably curses 60-90% of patients and substantially decreases the worm burden in those that are not cured. The drug causes titanic contractions and tegumental vacuoles that cause the worms to detach and die.

c) Oxamniquine is no longer available in the United states.

d) Re-examination of urine feces 1 month after treatment is recommended.

2. Surgical management.

a) Surgical procedures are reserved for complications of infection such as ureteral stenosis, bladder fibrosis, and bladder carcinoma. Procedures include ureteral dilation, ureteral reimplantation, partial cystectomy, bladder augmentation, and cystectomy with urinary diversion.

Referrences:

1-Allen J.F.(1888):Quoted by Kamel H: Ancient Egyptian medicine 4:310, 1964

2-Badr M.M.: The history of urology in Ancient Egypt. J.Int.Col.Surg. 30:404, 1963.

3- Badr M.M. (1981): Schistosomiasis in Ancient Egypt. In Detection of Bladder Cancer Associated with Schistosomiasis. El-Bolkainy and Chu. National Cancer Institute. Al-Ahram Press. Chapter 1, p 1-8,1981.

4-Neal P : Schistomiasis an unusual cause of ureteral obstruction a case history and perspective. Clin Med Res :2:216-227,2004

4-Ross AG: Current concepts: schistomiasis N Eng J Med 346-1212-1220,2002.

 
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