A CASE REPORT ON THE UNUSUAL FINDING OF

SCHISTOMA MANSONI OVA

Sivaranjini Alagiri , Anupma Jyoti Kindo , DhivyalakshmiSri Ramachandra Medical College & Research Institute

Chennai

INTRODUCTIONHumans are hosts to nearly 300 parasitic species.Parasitic infections are cosmopolitan and contribute

considerably to the global burden of communicable diseases.It is one of the chief concerns of public health in under -

developed & developing countries.Contributing factors are malnutrition, population density,

economic conditions, poor sanitation and life style.Increased incidence in developed countries may be attributed

to - mass influx of immigrant population from endemic areas - tourism - immunosuppression

F.E.G.Cox.Clin Microbiol Rev.2002

GLOBAL BURDENGlobal Burden of Disease Study 2013 - nearly 1million deaths are due to parasitic infections,

globally.

Plos Medicine Journals’ Blog,2015

HISTORY• Eggs of intestinal helminths have been found in mummified

faeces dating thousands of years back.• Earliest reports were documented by the Egyptians-Ebers

Papyrus of 1500BC.• Helminthiases have changed the course of Cold War. Acute

schistosomiasis weakened the Chinese troops ,long enough for American fleets to enter straits of Taiwan (blood-fluke that saved Formosa)

• German scientist Dr.Theodore Bilharz – first described adult schistosomes in portal vein of a cadaver(1851)

• Sir Patrick Manson(1902) discovered ova of S.mansoni.

SCHISTOSOMIASIS - EPIDEMIOLOGYSchistosomiasis is one of the oldest known parasitic infections.Prevalent in tropics & sub-tropicsAnnual incidence – 200 million globallyEstimated annual deaths d/t schistosomiasis is around 200,000An estimated 600 million people at risk in 76 endemic

countries.Schistosomiasis control has been successfully implemented

over the past 40 years in several countries, including Brazil, Cambodia, China, Egypt, Mauritius and Saudi Arabia

WHO Factsheets.2015http://whqlibdoc.who.int/trs/

WHO_TRS_912

GLOBAL DISTRIBUTION OF SCHISTOSOMIASIS

Michael Walsh (2012).Schistosomiasis. Infection Landscapes.

India is considered non-endemic for schistosomiasis – attributed to absence of intermediate host for human schistosomes.

There has been reports of sporadic indigenous cases.Cercarial dermatitis in Tribal villages of Assam , Chhattisgarh,

Madhya Pradesh and Jabalpur.Several schistosome species causing zoonotic disease are

prevalent in India.Endemic foci for human schistosomiasis - Gimvi village in Ratnagiri district, Maharashtra - Thirupparankundram village, Chennai - Lahager village, Madhya Pradesh

M. C. Agrawal and V. G. Rao.Journal of Parasitology Research.2011

IMPENDING THREAT TO INDIAAbundance of aquatic bodies and irrigation practices in India

provides ideal environment for the intermediate hosts.Population migration from endemic areas d/t globalisation and

tourism.Poor sanitation and lack of vector control measures pose a risk

for the spread.Under-reporting of schistosomiasis d/t - lack of suspicion - lack of public awareness to seek medical attention

EXPERIMENTS TO DETERMINE PREVALENCE OF INTERMEDIATE HOST IN INDIA

FINDINGS

Soparkar(1919) Cercarial fauna of snails were analysed in the water bodies in Bombay. All 17 species were animal schistosome cercariae

Annandale et al(1920) Tested 1532 common snails ,out of which 11 cercariae were found.All were negative for human schistosome and all were resistant to miracidia of S.haematobium

Gadgi et al(1956) Identified Ferrissia tenuis as the intermediate host of the S.haematobium , which caused an outbreak in Gimvi village,Maharashtra.

These experiments depict the absence of cercariae causinghuman schistosomiasis due to lack of suitable intermediate hosts and hence naturally controls the spread of schistosomiasis inIndia. Arunava Kali.Journal of Clinical and Diagnostic Research. 2015

SCHISTOSOMIASIS

Water borne helminthic infection Definitive host -HumansIntermediate host - freshwater snailsInfective form - cercariaeHabitat – mesenteric ,vesical & pelvic venous plexus.There are about 23 species of Schistosoma identified so far. Only 7 are anthropophilic.

  © Dr Peter Darben, Queensland University of Technology 

ANTHROPOPHILIC SCHISTOSOMESSchistosoma

speciesIntermediate Host Schistosomiasis Endemic Region

S. haematobium Bulinus species Urogenital Africa , Middle East

S. japonicum Oncomelania species

Gastrointestinal China, East Asia, Philippines

S. mansoni Biomphalaria species

Gastrointestinal Africa , South America, Caribbean, Middle East

S. intercalatum Bulinus species Gastrointestinal Africa

S. mekongi Neotricula aperta Gastrointestinal South East Asia

S. guineensis Bulinus forskalii Gastrointestinal West Africa

S. malayensis Robertsiella species Gastrointestinal South East Asia

Adapted from Melvin, Brook and Salum,1959

CASE REPORTIntestinal Schistosomiasis

PATIENT HISTORY• 26 year old male• College student from Chennai• Native of Nigeria• Recent travel to native place • Trekking and swimming

PRESENTING COMPLAINTS• Episodes of loose stools on & off for 2 weeks , with recent

episode lasting 4 days• Not associated with fever/ abdominal discomfort / nausea /

vomiting

INVESTIGATIONS• Haemoglobin - 15.3gm/dl• RBC count - 5.5 million/mm3

• Total leucocyte count - 5800 cells/mm3

• P49.7L43.2E1.9M5B0.2

• Platelet count - 2.49 lakhs/mm3

• PCV - 44.6%• MCV - 80.3fl• MCH - 27.5pg• MCHC - 34.3

• The patient was found to be retro-negative

STOOL EXAMINATIONSAMPLE - freshly passed stool collected in a sterile screw capped container GROSS EXAMINATION Colour – yellowish brown Consistency – watery Blood – present Mucous - presentMICROSCOPIC EXAMINATION Saline wet mount – plenty of oval shaped eggs measuring 120-175µm * 40-70µm - prominent sharp lateral spine - embryonated - non operculated

Ova of Schistosoma mansoni characterised by a sharp lateral spine

RESULTSBased on the morphology, eggs were identified to be

S.mansoni ova.Diagnosis was supported by his history of swimming in an

area, endemic for schistosomiasis.

TREATMENTPraziquantel – 40mg/kg Repeat stool sample was found to be negative for ova.Strict personal hygieneAbstinence from water activities to avoid infestation of water

bodies

REPORTS OF HUMAN SCHISTOSOMIASIS IN INDIA

REPORTED BY FINDINGSHatch (1878) First case of human schistosomiasis in India

Report of urinary schistosomiasis in 12 patientsPowell (1903) First indigenous case of human schistosomiasis in IndiaDe Sa et al(1949) First case of urinary schistosomiasis in Indian from Gimvi

village,Ratnagiri,Maharashtra. Index case leading to discovery of endemic focus

Santhanakrishnan et al Identified endemic focus in Thiruparankundram village,Chennai

Srivastava et al (1969) Identified lahager village, Madhya Pradesh as an endemic focus.Christopher et al(1905) Polymorphism of eggs. Presence of ova of both S.haematobium

and S.spindle in urine of South IndianHooton (1914) Indigenous case from Rajkot, GujaratDe Mello(1936) Urinary schistosomiasis in a young boy from GoaGadgil et al(1955) Indigenous case of S.haematobium infection from Nasik district.

Arunava Kali.Journal of Clinical and Diagnostic Research. 2015

DISCUSSIONThis case report is evidence enough to indicate that population

migration from endemic areas poses a significant threat of schistosomiasis in India.

Reports of sporadic cases indicate the possibility of indigenous snails to serve as intermediate host for the parasite.

Though cases of human schistosomiasis are very rare in India, occurrence of new hybrid strains due to co-existence of different species may serve as a potential risk for human infections.

Physicians are required to have a high level of suspicion for this disease while evaluating parasitic infestations .

It heralds importance of a surveillance strategy even in non-endemic areas like India, to enable early identification of cases and initiate prompt treatment ,thereby checking the spread of this neglected tropical disease.