Schistosomiasis(bilharzia

)

By Dr. Karl

Sometimes referred to as Sometimes referred to as bilharziabilharzias, s, bilharziasis, or snail fever, bilharziasis, or snail fever,

is a parasitic disease caused by is a parasitic disease caused by trematodetrematode(flukes) flatworms of the genus (flukes) flatworms of the genus Schistosoma.Schistosoma.

Belong to Phylum PlatyhelminthesBelong to Phylum Platyhelminthes

History

schistosomiasis was discovered by schistosomiasis was discovered by Theodore Theodore BilharzBilharz, a German surgeon working in Cairo, , a German surgeon working in Cairo, who first identified the etiological agent who first identified the etiological agent Schistosoma hematobium in 1851Schistosoma hematobium in 1851

The first doctor who described the entire The first doctor who described the entire disease cycle was Pirajá da Silva in 1908.disease cycle was Pirajá da Silva in 1908.

It was a common cause of death for Ancient It was a common cause of death for Ancient Egyptians in the Greco-Roman Period.Egyptians in the Greco-Roman Period.

Schistosoma mansoniSchistosoma mansoni

Schistosoma hematobiumSchistosoma hematobium

Schistosoma japonicumSchistosoma japonicum

S. intercalatumS. intercalatum

S. mekongiS. mekongi

***Trichobilharzia ocellata (cause swimmers ***Trichobilharzia ocellata (cause swimmers itch)itch)

Four species routinely infect the human host, Four species routinely infect the human host, and several others rarely do so. and several others rarely do so.

classification

Schistosoma eggs (haematobium with terminal stings - mansoni with lateral stings)

Epidemiology

It is endemic to at least 76 tropical and sub-It is endemic to at least 76 tropical and sub-tropical countries. tropical countries.

more than 200 million people are infected more than 200 million people are infected worldwide. In terms of impact this disease is worldwide. In terms of impact this disease is second only to malaria as the most second only to malaria as the most devastating parasitic disease. Schistosomiasis devastating parasitic disease. Schistosomiasis is considered one of the is considered one of the Neglected Tropical Neglected Tropical Diseases Diseases (NTDs)(NTDs)

The disease is found in tropical countries in The disease is found in tropical countries in Africa, the Caribbean, eastern South America, Africa, the Caribbean, eastern South America, Southeast Asia and in the Middle East. Southeast Asia and in the Middle East.

Schistosoma mansoni Schistosoma mansoni is found in parts of is found in parts of South America and the Caribbean, Africa, and South America and the Caribbean, Africa, and the Middle East;the Middle East;

S. haematobium S. haematobium in Africa and the Middle East; in Africa and the Middle East; and and S. japonicum S. japonicum in the Far East. in the Far East.

S. mekongi S. mekongi and and S. intercalatum S. intercalatum are found are found locally in Southeast Asia and central West locally in Southeast Asia and central West Africa, respectivelyAfrica, respectively

Transmission

Risk Factor- Wading and swimming in fresh Risk Factor- Wading and swimming in fresh water in tropical regions water in tropical regions

You get a schistosoma infection through You get a schistosoma infection through contact with contaminated water. The parasite contact with contaminated water. The parasite in its infective stages is called a cercaria. It in its infective stages is called a cercaria. It swims freely in open bodies of water.swims freely in open bodies of water.

cercaria

Skin vesicles on the forearm, created by the penetration of Schistosoma

pathophysiology

Schistosomiasis is due to immunologic Schistosomiasis is due to immunologic reactions to Schistosoma eggs trapped reactions to Schistosoma eggs trapped in tissues. Antigens released from the in tissues. Antigens released from the egg stimulate a granulomatous reaction egg stimulate a granulomatous reaction involving T cells, macrophages, and involving T cells, macrophages, and eosinophils that results in clinical eosinophils that results in clinical disease disease

Initially, the inflammatory reaction is Initially, the inflammatory reaction is readily reversible. In the latter stages of readily reversible. In the latter stages of the disease, the pathology is associated the disease, the pathology is associated with collagen deposition and fibrosis, with collagen deposition and fibrosis, resulting in organ damage that may be resulting in organ damage that may be only partially reversible.only partially reversible.

Photomicrography of bladder in S. hematobium infection, showing clusters of the parasite eggs with intense eosinophilia

Host

All snail species susceptible to infection with All snail species susceptible to infection with Schistosoma mansoni and S. haematobium Schistosoma mansoni and S. haematobium belong to the family belong to the family PlanorbidaePlanorbidae in the in the subclass Pulmonata.subclass Pulmonata.

Schistosoma mansoni infects snails in the Schistosoma mansoni infects snails in the genus genus BiomphalariaBiomphalaria, and these can also , and these can also become infected with S. mansoni-S. become infected with S. mansoni-S. intercalatum hybrids, S. rodhaini and S. intercalatum hybrids, S. rodhaini and S. eduardiense. eduardiense.

Schistosoma haematobium infects pulmonate Schistosoma haematobium infects pulmonate snails of the genus snails of the genus BulinusBulinus..

OncomelaniaOncomelania for S japonicum for S japonicum

TriculaTricula (Neotricula aperta) for S mekongi (Neotricula aperta) for S mekongi

Clinical Presentation

Symptoms and signs depend on the number Symptoms and signs depend on the number and location of eggs trapped in the tissues.and location of eggs trapped in the tissues.

Eggs can end up in the skin, brain, Eggs can end up in the skin, brain, muscle, adrenal glands, and eyes. As muscle, adrenal glands, and eyes. As the eggs penetrate the urinary system, the eggs penetrate the urinary system, they can find their way to the female they can find their way to the female genital region and form granulomas in genital region and form granulomas in the uterus, fallopian tube, and ovaries. the uterus, fallopian tube, and ovaries.

Central nervous system (CNS) Central nervous system (CNS) involvement occurs because of involvement occurs because of embolization of eggs from the portal embolization of eggs from the portal mesenteric system to the brain and mesenteric system to the brain and spinal cord via the paravertebral spinal cord via the paravertebral venous plexus.venous plexus.

location

Intestinal

S. mansoniS. mansoni

S. japonicumS. japonicum

S. intercalatumS. intercalatum

S. mekongiS. mekongi

Urinary

S. hematobiumS. hematobium

S. japonicum eggs in hepatic portal tract

Acute schistosomiasisKatayama syndromeKatayama syndrome- is a systemic, serum - is a systemic, serum sickness-like illness that develops after several sickness-like illness that develops after several weeks in some, but not most, individuals with weeks in some, but not most, individuals with new schistosomal infections. new schistosomal infections.

is associated with marked peripheral is associated with marked peripheral eosinophilia and circulating immune eosinophilia and circulating immune complexescomplexes

most common with S japonicum and S most common with S japonicum and S mansoni infectionsmansoni infections

is most likely to occur in heavily infected is most likely to occur in heavily infected individuals after primary infectionindividuals after primary infection

Chronic Intestinal Schistosomiasis

disease disease onset is insidiousonset is insidious- Patients with - Patients with symptomatic chronic schistosomiasis may symptomatic chronic schistosomiasis may present months to years after primary present months to years after primary exposureexposure

portal hypertension with splenomegaly portal hypertension with splenomegaly oesophagial varices, hypersplenism, ascitis, oesophagial varices, hypersplenism, ascitis, dyspepsia, flatulence, and pain are present in dyspepsia, flatulence, and pain are present in the left hypochondriumthe left hypochondrium

pulmonary hypertensionpulmonary hypertension

CNS lesions: spine - transverse myelitis CNS lesions: spine - transverse myelitis cerebral – seizures (S. japonicum) -Dizziness, cerebral – seizures (S. japonicum) -Dizziness, nausea, and increased intracranial pressure, nausea, and increased intracranial pressure, Visual scintillation from occipital massVisual scintillation from occipital mass

intestinal polyposis: intestinal granulomatosis: intestinal polyposis: intestinal granulomatosis: contractures of colon, intusseception, melena, contractures of colon, intusseception, melena, Generalized lymphadenopathyGeneralized lymphadenopathy

Female genital schistosomiasis- Postcoital Female genital schistosomiasis- Postcoital bleeding, Genital ulceration, Irregular bleeding, Genital ulceration, Irregular menstruation, Pelvic painmenstruation, Pelvic pain

Cardiopulmonary schistosomiasis - larval Cardiopulmonary schistosomiasis - larval pneumonitis with a cough, mild wheezing, and pneumonitis with a cough, mild wheezing, and a low-grade fever, while in schistosomal cor a low-grade fever, while in schistosomal cor pulmonale, easy fatigability, palpitations, pulmonale, easy fatigability, palpitations, dyspnea on exertion, and hemoptysisdyspnea on exertion, and hemoptysis

Splenomegaly due to bilharziosis: a drawing of the contour before ablation and the spleen after excision

Tortuous Varicosities in Chronic Schistosomiasis

Trichobilharzia ocellata

Cercarial dermatitis of humans ("swimmer's itch", "Badedermatitis", "Weiherhippel")

Schistosoma haematobium

Urinary schistosomiasis

Schistosoma near urethra

PresentationPresentation

hematuria (terminal)hematuria (terminal)

urinary frequencyurinary frequency

pyuriapyuria

pyelonephritispyelonephritis

obstructive uropathyobstructive uropathy

cancer of bladder (squamous cell)cancer of bladder (squamous cell)

distant metastases (spinal column)distant metastases (spinal column)

(pulmonary hypertension)(pulmonary hypertension)

diagnostics

symptoms mimic any acute viral, bacterial, or symptoms mimic any acute viral, bacterial, or malarial illness.malarial illness.

Obtaining a careful travel history, including Obtaining a careful travel history, including drinking water sources and recreational drinking water sources and recreational activities, is important. Symptoms are likely activities, is important. Symptoms are likely secondary to immune complex formation secondary to immune complex formation following egg deposition in tissues; the illness following egg deposition in tissues; the illness resembles serum sickness.resembles serum sickness.

Diagnosis: intestinal schistosomiasis

1. History of freshwater exposure1. History of freshwater exposure

2. Stool for O&P (egg counts and viability)2. Stool for O&P (egg counts and viability)

3. Serology-- Elisa and Western Blot3. Serology-- Elisa and Western Blot

4. Antigen capture4. Antigen capture

5. Eosinophilia5. Eosinophilia

6. Rectal snips or biopsies6. Rectal snips or biopsies

7. Liver biopsy7. Liver biopsy

8. Ultrasound or CT of abdomen8. Ultrasound or CT of abdomen

LaboratoryLaboratory

debris in urinedebris in urine

eggs in urine (overnight-millipore)eggs in urine (overnight-millipore)

I.V.P. abnormalitiesI.V.P. abnormalities

cystoscopycystoscopy

serologyserology

Schistosoma Mansoni in the Cecum ( Magnification Colonoscope.)

This 34 year-old male, a routine colonoscopy was performed a Schistosoma Mansoni was found at the cecum.

Management

Management strategies:

A.A. Treatment of local irritation Treatment of local irritation ( (swimmers itchswimmers itch))

B.B. Treatment of allergic reaction to cercarial Treatment of allergic reaction to cercarial entryentry (fever, rash, myalgia, pneumonitis - (fever, rash, myalgia, pneumonitis - Katayama feverKatayama fever))

C.C. Control of egg laying to prevent Control of egg laying to prevent complicationscomplications

D.D. Treatment of complications Treatment of complications

Swimmers itch & Katayama Swimmers itch & Katayama feverfever::

Anti-allergic (chlopheniramine), Anti-allergic (chlopheniramine), paracetamol, steroids (prednisone or paracetamol, steroids (prednisone or hydrocortisone)hydrocortisone)

Control of egg laying & Control of egg laying & complications:complications:

Praziquantel:Praziquantel: Effective against all 3 forms Effective against all 3 forms

↑ ↑ entry of Caentry of Ca++ ++ to cell memb, paralyze, detach to cell memb, paralyze, detach & kill& kill

Taken after meal without chewing (bitter)Taken after meal without chewing (bitter)

May increase symptoms of Katayama fever May increase symptoms of Katayama fever

(↑ allergic reaction due to dead cestodes)(↑ allergic reaction due to dead cestodes)

Oxamniquine:Oxamniquine: Effective only for Effective only for S. mansoniS. mansoni

Metrifonate:Metrifonate: Only for Only for S. haematobiumS. haematobium

Outlook (Prognosis

Treatment before significant damage or severe Treatment before significant damage or severe complications occur usually produces good complications occur usually produces good results.results.

Complications

HemospermiaHemospermia

Squamous cell bladder cancerSquamous cell bladder cancer

Sepsis (Salmonella)Sepsis (Salmonella)

Pulmonary hypertensionPulmonary hypertension

Cor pulmonaleCor pulmonale

Neuroschistosomiasis - Transverse myelitis, Neuroschistosomiasis - Transverse myelitis, paralysis, and cerebral microinfarctsparalysis, and cerebral microinfarcts

InfertilityInfertility

Severe anemiaSevere anemia

Low N birth-weight babiesLow N birth-weight babies

Spontaneous abortionSpontaneous abortion

Higher risk for ectopic pregnanciesHigher risk for ectopic pregnancies

End-organ diseaseEnd-organ disease

Portal hypertensionPortal hypertension

Obstructive uropathyObstructive uropathy

Pregnancy complications from vulvar or Pregnancy complications from vulvar or fallopian granulomafallopian granuloma

Carcinoma of the liver, bladder, or gallbladderCarcinoma of the liver, bladder, or gallbladder

Prevention

Avoid swimming or bathing in contaminated or Avoid swimming or bathing in contaminated or potentially contaminated waterpotentially contaminated water

Avoid bodies of water of unknown safetyAvoid bodies of water of unknown safety

Snails are an intermediate host for the Snails are an intermediate host for the parasite. Getting rid of snails in bodies of parasite. Getting rid of snails in bodies of water used by humans would help prevent water used by humans would help prevent infection.infection.