BALANTIDIUM COLIDisease , Epidemiology and laboratory diagnosis

Introduction History Taxonomy Molecular biology Parasitology Metabolism Viability Reproduction Pathogenesis Clinical features

Epidemiology Lab diagnosis Treatment Studies in India Prevention

INTRODUCTION Balantidium coli is a cosmopolitan parasitic

opportunistic pathogen found Worldwide.

Largest protozoan and the only ciliate to parasitize humans which causes Balantidiasis.

Zoonotic disease and pig is the reservoir host. Life cycle is completed in the single host

Mimics the dysentry of E. histolytica and human to human transmission is possible but rare.

Death is a rare sequelae.

HISTORY

1857- Pets Henrick Malstem was first person to recognize the organism in two human beings.

1861- Rudolf Leukart described a morpholgically similar organism in the large intestine of pigs.

1863- Stein pointed out both to be the same species and put it in the Genus Balantidium.

1922-Mc Donald proposed that the pig & human species should be separated as balantidium suis & balantidium coli

1927- Rees and Jameson were both sucessful in cultivating the balantidium coli using ringer solution ,starch etc

CONTD----------

1953- Agosin & von Brand found it survives both in aerobic as well as anaerobic condition.

1957- Temples & Lysenko found that Balantidium coli produces enzyme called Hyluronidase which helps in the invasion of the tissue.

SYNONYMS

Different names were given to this organisms by putting it into different genera-

Paramecium coli- Malstem (1857) Leukophyra coli- Stein(1860) Holophyra coli- Leukart (1861)

In 1863 Stein transferred the the species to the Genus Balantidium which was created by Claparede & Lachmann(1858)

TAXONOMY

IN 1980 the International society of Protistologists committee have

recently revised the taxonomy based on the new information regarding this organisms

KINGDOM-PROTISTA

PHYLUM-CILIOPHORA

CLASS-LITOSTOMATEA

ORDER-VESTIBULIFERIDA

FAMILY-BALANTIDIAE

SPECIES-Balantidium coli

Presently based on morphological basis it is classsified into 50 species.

Different species affecting different animals- balantidium coli- humans balantidium suis-pig balantidium caviae-guinea pig balantidium blatarum-cockroaches

balantidium jocularum- fish

RNA sequencing helps in resolving taxonomy

Are balantidium coli & suis same species or different?

MOLECULAR BIOLOGY

There is a need of nucleotide sequencing for definitive taxonomy.

Presently 2 studies on balantidium nucleotide sequencing has been done-

1. Based on small subunit rRNA(AF029763)2. Based on internal transcribed spacers.

(AF045030)

Additional information is required,

PARASITOLOGY

CHARACTERS OF CILIATES Ciliary organelles present for locomotion.

Two nucleii- • Macronucleii- • Micronucleii-

Two contractile vacuoles for osmoregulatory capacity.

REPRODUCTION- 1. ASEXUAL/BINARY FISSION2. SEXUAL/ CONJUGATION

THE PARASITE---------

TROPHOZOITES CYST

SHAPE Oval pointed at anterior end spherical

SIZE 50-130µ 40- 60µ

SURFACE& MOTILITY

Covered in cilia motile (rotatory)

Covered with thick , hard cyst wall, (nonmotile)

REPRODUCTION Binary fission/conjugation Non reproductive

INFECTIOUS Non infective infective

IMP CELL STRUCTURE

Cytostome, 2 contractile vacuoles

Cyst wall

DIAGNOSIS Less often in feces, frequently in tissue

Commonly found in feces

PHYSIOLOGY B.coli ingest a variety of organisms like

bacteria, starch grains, RBCs, leukocytes, cells & fat droplet

Food particles are digested through the cytostome which leads into cytopharynx/gullet.

Base of the cytopharynx these particles collect in vacuoles & are digested by the enzymes.

The indigestible residue is eliminated through the anal opening,Cytopyge

METABOLISM

Is able to survive both in aerobic as well as anaerobic conditions.

Carbohydrates are the main source of energy.

Has different enzymes which acts as virulence factors-

Peroxisomes-protects from oxidising agents. Glucose phosphatase/alk phosphatase-

glucose metabolism. Hyaluronidase-helps in the invasion of the

parasite No toxins are secreted.

VIABILITY

Trophozoites- in moist environment may survive at 22o celsius for 10 days.

Sensitive to temperature ( 20 – 40o C) and pH <5

In culture-Survive for 24-48 hrs in culture maintained at 40 o celsius.

Cyst- comparatively resistant to temp & pH and survive for weeks in moist environment.

o ASEXUAL REPRODUCTION – BY BINARY FISSION-

o Divides macronucleus ( amitotically) & micronucleus( mitotically) first

o The body constricts midway between the poles to form two new individuals . After their division retreat towards the opposite poles,

A new cytostome is formed in the posterior daughter cell.

o CONJUGATION- conjugation tube found at the oral apparatus & exchange of the micronucleus products of meiosis takes place.

o Binary fission is required for continuing life of the species o Conjugation considered as a means of maintaining homogeneity in

mixed strains

PATHOGENESIS

DISEASE

FACTORS CONTRIBUTING TO THE DISEASE Immunosuppressive conditions, Nutritional status, intestinal flora, parasitic load, achlorhydria, RISK FACTOR-persons who handle pigs like

farmers, zookeepers, veterinarians etc.

SOURCE OF INFECTION – Food/water contaminated with pig

feces MODE OF TRANSMISSION –Ingestion. Pigs to humans or humans to humans

transmission is possible

CLINICAL FEATURES

INTESTINAL EXTRAINTESTTINAL

ASYMPTOMATIC CHRONIC FULMINANT

Reservoir non bloody bloody mucoid stools, cramps, stools,intestinal

halitosis, abd pain. hemorrhage

CFR-30% in fulminant cases

CLINICL FEATURES CONTD

EXTRA INTESTINAL- Appendicitis , genitourinary tract infection, liver abscess, peritonitis, renal failure etc.

Several reports in the literature of Balantidium coli causing lung infection like Pneumonia.

Commonly seen in immunosuppressive conditions like cancer, diabetes, leukemia, pts on immunosuppressive drugs,

EPIDEMIOLOGY

World wide in distribution particularly in the tropical & sub tropical countries.

Worldwide prevalence – 1.2%-1%. Also includes south & central America ,

Phillipines, Iran, Central Asia, New Guinea(28%) & Pacific islands.

OUTBREAK – In 1971 largest outbreak seen in the Island of Turk in the Caroline island following a typhoon,110 persons were affected.

It was associated with many other water borne infections like Ascaris & Entamoeba

MAJOR FACTORS LEADING TO BALANTIDIASIS

Lack of proper disposals that contaminate water sources with swine feces.

Subtropical & tropical countries favorable climatic conditions.

Close contact between humans & pigs.

ENDEMIC AREAS- Philippines, Papua, New Guinea, West Irian in western pacific, rural areas of South America

Infection in women is twice common as in men. (Prevalence studies done in New Guinea in 1950)

ANIMAL RESERVOIRS

PIGS are commonly infected & are significant animal reservoir.

Prevalance-20-100% Commensals in large intestine & shed in

large amounts in feces. Humans rearing the pigs are susceptible.

Commonly transmitted through contaminated water without sanitation

OTHER ANIMALS- Rodents, cats , dogs , monkeys , baboons,camels, buffaloes etc

LABORATORY INFECTIONS

No reports till now

Cyst may survive drying on the bench tops & other laboratory surfaces.

1% sodium hypochlorite is effective.

BSL 2 precautions are recommended.

Glooves and lab coats are appropriate for protection

LABORATORY DIAGNOSIS

BALANTIDIASIS is an uncommon infection suspected in those patients who work in close contact with pigs, travellers,in endemic areas etc.

SAMPLE COLLECTION-Fresh stool sample and tissue collected by sigmoidoscopy,

Bronchoalveolar lavage in pneumonia cases. MICROSCOPIC EXAMINATION- Wet mount preparation/Lugols iodine -to look

for an active motile ciliates/ cysts. Cysts are found more commonly in formed

stools and trophozoites in tissues and feces.

CONTD

Sample collected and examined for several days as it can be erratic.

Fixative used – 10% formalin / polyvinyl alcohol

Concentration methods – increase the load of cyst

Tissues samples mainly collected by sigmoidoscopy from an ulcer site in the colon

Trophozoites are seen more in number.

Respiratory tract specimen –confusion b/n ciliated trophozoites and Ciliated Epithelial Cells

Differences B/N them should be made out.

PHASE CONTRAST MIROSCOPE can be used to visualise the oral apparatus, cilia & nucleus.

CULTIVATION of the parasite- Media supporting the growth of Entamoeba

histolytica supports B.coli. Prefers to grow in microaerophilic / anaerobic

condition. Temperature-20 -40oC. Biphasic media-inspissated egg yolk, serum

& streptomycin.

Monoxenic culture- balantidium coli with Escherichia coli& antibiotics.

Xenic culture like- Diamonds media, TYSGM media LE media Robinson’s media

o Rice starch plays an important ingredient which is a carbohydrate & source of energy

SEROLOGICAL TEST

Demonstrating a humoural response in Balantidiasis by an indirect immunoflourescense test ( IFT).

Using anti balantidium rabbit serum the ciliates were immobilized within minutes.

( Zaman, TRSTMH ;1964: Vol 58)

It would sidestep the intesive examination of stool sample

TREATMENT

Drugs that are used are metronidazole , secnidazole,tinidazole, tetracycline,doxycycline.

Drug of choice-tetracycline 500mg QID × 10 days

metronidazole 750mgTID×5-7 days

Carriers need to be treated .

Till now no relapse and resistant is reported

RECENT STUDIES IN INDIA

Intestinal parasites causing diarrhoea in Delhi.

South Asia Journal Tropical Medicine Public Health:Dec 2002

Most common parasite in india causing diarrhoea is Entamoeba & Giardia (11%). Balantidium coli cause only 2.3% of infection

CONTD

Parasitic infection in Mumbai Original Research Article; 2006 Out of 1924 HIV + ve stool sample 115 were parasite

positive. helminthic infestation( 85.17%) & protozoal infection (14.76)

PREVENTION

By hygiene practices, proper water sanitation and proper disposal of fecal material.

Pigs are the main animal reservoir & a significant source. Barrier b/n the swine & human should be established

Clean water drinking and the communities should be taught the significance of potable water.

Personal hygiene . Importance of hand washing should be taught to the people.

Both Symptomatic patients/Asymptomatic carriers should be treated with antibiotics.

This will prevent all water/ food borne parasitic infections

REFERENCES CURRENT STATUS OF BALANTIDIUM COLI:CMR 2008

THE CILIATE PROTOZOA:BALANTIDIUNM COLI ,CRAIG FAUST ‘S CLINICAL PARASITOLOGY, ED 8

THE CILIATE OF MAN, TEXT BOOK OF PARSITOLOGY . BELDING.

3 rd EDITION.

THE CILIATE PROTOZOA: BALANTIDIUN COLI,CLINICAL PARASITOLOGY, BEAVER 9TH EDITION.

BALANTIDIUM COLI. TOPLEY& WILSON . 10 TH EDITION

TEXT OF MEDICAL PARASITOLOGY. 3 rd EDITION SUBHASH CHANDRA PARIJA.

MANY ARTICLES