Cestodes

Micro/Para (Dra. Bunyi) Cestodes 30 January 2008

Cestode Infections  Intestinal cestodes  Taenia saginata  T. solium  Hymenolepis nana  H. diminuta  Dypillidum caninum  D. latum  Extraintestinal cestodes  Echinococcus sp.  Spirometra Taenia saginata  Known as the beef tapeworm  Humans serve only as definitive host (Not a intermediate host)  Human cysticercosis Does Not occur T. saginata: Morphology

 Vagina has a sphincter  Gravid proglottids  Proglottids are longer than they are wide  Uterus is distended with ova and has 15 to 20 lateral branches  Genital pores of proglottids are irregularly shaped  Ova  Spherical or subspherical in shape  In color, with a thick embryophore which appears striated because of numerous pits  Inside the eggshell is the oncosphere or embryo 30-45 µm in diameter Taenia saginata: Life cycle

 Adult worm

Inhabits upper jejunum May live up to 25 years Measure 4-10m in length (25m) 1,000-4,000 proglottids SCOLEX: cuboidal – 1-2 mm in diameter 4 acetabula Devoid of hooks or rostellum Mature proglottids  Contain mature male and female reproductive organs  2 large varies and a median clubbed uterus  Follicular testes 300-400    

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Cams, shar, joy

 Gravid proglottids undergo apolysis  passed out/crawls out  eggs are released

 Cysticercus bovis: infective stage; ovoidal,

milky white, 10mm diameter, single scolex invaginated into a fluid-filled bladder  Only 1 adult tapeworm is present in T. saginata infections T. solium  Known as the pork tapeworm of man  Man serve as both a definitive host and an intermediate host 1 of 10

Micro/PARA – Cestodes by Dra. Bunyi

 Both intestinal and tissue infections occur in man T. solium: Morphology  Adult worm  Inhabits the upper small intestines  Shorter than T. saginata  Less number of proglottids  Adults measure 2-4m in length  800-1,000 proglottids  SCOLEX: smaller, more spherical  4 acetabula  Cushion-like rostellum with a double crown of 2530 large and small hooks  Mature proglottids  Presence of accessory ovarian lobe  Absence of vaginal sphincter  Smaller number of follicular testes 100-200  Gravid proglottids  Contains 7-15 uterine lateral branches  Also undergo apolysis but not very motile  Ova  Indistinguishing from T. saginata T. solium: Life cycle ****Same as T. saginata. Pls check above life cycle****** Taenia solium: Pathology and Clinical Manifestations  Disease caused  Ingestion of eggs  cysticercosis  Ingestion of cysticercus  taeniasis  Taeniasis symptoms Site Symptoms Pathogenesis Gastrointestinal Abdominal Physical discomfort, presence of the epigastric pain, worm vomiting Other organs Cyst formation Physical mass (cysticercosis) in brain, eye, and lungs, and liver inflammation may cause related

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symptoms  Cysticercosis

T. solium: diagnosis  Symptoms  History  …(naharangan po kasi ng pictures dun sa binigay na hand-out kaya di mabasa. Kung sino po nakakopya pa-share na lang po. Thanks!)  …  Gravid proglottids and/or eggs in the stool  Cysticercosis diagnosis  Radiographic localization of cysticercal lesions in tissues  Neurocysticercosis  CT Scan findings: 1. Round lowdensity area without surrounding enhancement after administration of contrast dye (viable larva without inflammation) 2. Ring-like enhancement after injection of contrast dye (dead larva) 3. Small calcified area within a cystic space (dead scolex) Treatment: Taeniasis  Praziquantel: 5-10mg/kg as single dose for both adults and children  scolex expulsion is essential  criteria for cure:  recovery of the scolex  a negative stool examination 3 months after treatment Treatment: Cysticercosis  Neurocyticercosis  Praziquantel: 50-75 mg/kg divided into 3 doses for 30 days or  Albendazole: 400mg 2x a day for 830 days  Steroids  Surgical removal  Ocular cysticercosis  Surgical removal Epidemiology

Micro/PARA – Cestodes by Dra. Bunyi

 Related to the habit of eating raw or improperly cooked meat  T. solium: Slavic countries, Latin America, Southeast Asia, China and India  T. saginata: Etiopia and East Africa, Japan, SEA, Europe, Australia, Canada, US  Philippines: prevalence of taeniasis – 0.56%; Northern Luzon Taeniasis: Prevention  Adequate cooking of meat  Freezing meat below 100C  Hymenolepis nana  Common name: dwarf tapeworm  Disease caused: Hymenolepiasis nana; dwarf tapeworm infection H. nana: Geographic distribution  Primarily limited in human beings to children in warm climates  Prevalent throughout India, parts of the USSR, countries bordering the Mediterranean, all countries of Latin America, Hawaii and some of the islands of South and Southwest Pacific  Common tapeworm in Southeastern US H. nana: Morphology  Adult worm

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 Length: 25-40mm  Number of proglottid: 200 SCOLEX 1. Small and globular 2. Bears a short retractile rostellum with a single ring of 20-30 minute hooklets 3. Provided with 4 cup-shaped suckers Neck – long and slender Immature proglottid – undifferentiated Mature proglottid 1. Trapezoidal about 4x as broad as long 2. Has a single genital pore on its left side towards the anterior border 3. Has 3 round testes and a bilobed ovary Ripe or gravid proglottid – contains the sacculate uterus filled with eggs Ova  Grayish hyaline, nearly spherical  20-40µm in diameter  Two thin membranous shells

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 Inner membrane with two polar thickenings each provided with 4-8 threadlike filaments extending into the space between the two shells  Hexacanth embryo with 6 hooklets enclosed by 2 membranes H. nana: Life cycle

H. nana: Epidemiology  Human strain  Only human tapeworm that does not require an intermediate host to complete its life cycle

Micro/PARA – Cestodes by Dra. Bunyi

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 Man is the natural final host  Infective stage is the embryonated ova transmitted to man through the agency of foods and drinks particularly raw leafy vegetables usually eaten as raw salad  It is more common in children and in institutionalized group  Humanity is the chief source of infection Murine strain, H. nana var. fraternal  Final hosts are rats and mice  Man is an accidental final host  Intermediate hosts are fleas and beetles  Infection of definitive hosts results from the ingestion of intermediate hosts harboring the 4cysticercoid larva H. nana: Mode of Transmission Direct hand to mouth Less frequently, by contaminated food or water Possibly, by indirect intermediate hosts H. nana: Symptomatology Infection with a few H. nana may produce no symptoms It may be responsible for: 1. Diarrhea 2. Anorexia 3. Vomiting 4. Insomnia 5. Loss of appetite and weight 6. Irritability 7. Pruritus of the anus and nose 8. Urticaria 9. Choreiform symptoms Heavy infection is invariably pathogenic 1. Moderate to profuse diarrheic stools 2. Abdominal pain 3. Anorexia and exaggerated disorders 4. Extreme apathy 5. Epileptiform seizures H. nana: Laboratory Diagnosis Recovery of the characteristic ova in the stools Light cases with the aid of acid ether concentration technique H. nana: Treatment Praziquantel – 25 mg/kg in single dose Niclosamide – 2 g each day for 5-7 days  Children – half of the adult dose

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 Paromomycin – 45 mg/kg daily, given in 4 doses at hour intervals for a period of 5 days H. nana: Prevention  Human strain a. Avoid ingestion of eggs by not eating raw vegetables or salad b. Personal hygiene c. Cleanliness of toilet seats  Murine strain a. Eradicate the rats and mice around the house b. Residual spraying of their nests and burrows with insecticides c. Protection of cooked foods from arthropods Hymenolepis diminuta  Common name: Rat tapeworm  Disease caused: Hymenolepiasis diminuta; rat tapeworm infection H. diminuta: Geographic distribution  Cosmopolitan parasite of rats, mice, and other rodents  Has been reported from human hosts usually from children in India, Indonesia, USSR, Japan, Philippines, S. Europe, Latin America from Argentina to Mexico and Cuba and from several parts of the US H. diminuta: Morphology  Adult worm  Length: 10-60cm by 35mm  Number of proglottids: 800-1,000  SCOLEX  Knob-like; club-shaped  Provided with a rudimentary apical unarmed rostellum or a deep apical suctorial pocket without rostral hooklets  Provided with four relatively small cup-shaped suckers  Neck – short and stout  Immature proglottid – undifferentiated  Mature proglottid  0.8 by 2.5mm  Same as H. nana only the segments are larger  Ripe or gravid proglottid – sacculate uterus with egg masses  Ova  Hyaline with straw-colored hue

Micro/PARA – Cestodes by Dra. Bunyi

 Broadly ovoid or   

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subspherical 58 by 86µm 2 egg membranes, outer and inner Inner membrane with 2 polar thickenings but with the absence of filaments Considerable space between outer and inner Hexacanth embryo enclosed by 2 membranes H. diminuta: Life cycle

H. diminuta: Epidemiology Man is only an accidental final host Rats and other murines are the natural final hosts Principal intermediate hosts are the larval rat, mouse fleas and adult mealworm beetle Other intermediate hosts – fleas, myriapods, cockroaches, beetles, lepidopterans Infective stage to the final host is the cysticercoids larva in the arthropod host Humans are infected accidentally by food or hands contaminated with infected insects H. diminuta: Symptomatology H. diminuta usually produces no symptoms Indigestion and abdominal pain are the presenting complaints in infants H. diminuta: Lab Diagnosis Recovery of the characteristic ova in the stools H. diminuta: Treatment Same as H. nana H. diminuta: Prevention Eradicate the rats and mice around the house

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 Residual spraying of their nests and burrows with insecticides  Protection of cooked foods from arthropods Dipylidium caninum  Common name: Double-pores dog tapeworm  Disease caused: Dipylidiasis; dog tapeworm infection D. caninum: Geographic Distribution  A common tapeworm of the dog and cat throughout the world; also reported from wild cats and foxes  Human infection is rare but reported from European, China, and the Phils.  In the Phils., survey of dogs – prevalence of 5.19% - 36%; dog and cat fleas – 2.4% Dipylidium caninum: Morphology  Adult worm  Pale reddish adult worm measuring 1570cm in length  Strobila – a chain of melon-shaped proglottids  Number of proglottids – 60-175  SCOLEX  Rhomboidal  Retractile conical rostellum armed with 30150 rose thorn-shaped hooklets arranged in transverse rows  4 prominent oval suckers  Neck – short and slender  Immature proglottid  Broader than long when very young  Square as they become older  Mature proglottid  Vaseshaped, melon seedshaped or pumpkin seed-shaped  Double sets of reproductive organs  Genital atrium on each side of the segment  Gravid proglottid  Vase-shaped, melon seed-shaped or pumpkin seed-shaped  Filled with polygonal shaped uterine egg pockets or egg capsules containing 8 to 15 eggs

Micro/PARA – Cestodes by Dra. Bunyi

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 Ova Spherical Thick

albuminous covering  Hexacanth embryo with 3 pairs of lancet-shaped hooklets D. caninum: Life cycle

D. caninum: Epidemiology  Definitive hosts are dogs, cats and wild carnivore  Man especially children are only accidental final hosts  Intermediate hosts are larval fleas of the dog, cat and human being and the dog louse o Dog flea – Ctenocephalides canis o Cat flea – C. felis o Human flea – Pulex irritans o Dog louse – Trichodectes canis  Ingestion of the infected fleas cause infection of the final host  Infants and young children are usually infected because of their close contact with their pet cats D. caninum: Symptomatology  Light infections – asymptomatic  May cause: 1. Slight intestinal discomfort 2. Epigastric pain 3. Diarrhea 4. Anal pruritus 5. Allergic reactions D. caninum: Diagnosis

 Clinical – difficult since symptoms are nonspecific  Laboratory  Based upon the demonstration of: 1. A single or chain of melonshaped proglottids 2. Egg pockets or egg capsules 3. Embryonated ova 4. Ripe or gravid proglottid D. caninum: Treatment  Praziquantel – 10mg/kg in a single dose  Niclosamide – 4 tablets (2g) chewed thoroughly in a single dose after a light meal  Paromomycin – 1g every 4 hours for 4 doses  Quinacrine hydrochloride – 0.8g given over a half hour interval D. caninum: Prevention  Periodic deworming of pet cats and dogs is recommended  Insecticide dusting of dogs and cats are effective against fleas  The potential danger of playing with pets must be included in the health education of children  Small children should not be allowed to fondle dogs and cats infected with fleas and lice Diphyllobothrium latum  Common name: Broad or fish tapeworm  Disease caused: Diphyllobothriasis; fish tapeworm infection; broad tapeworm infection D. latum: Geographic Distribution  Prevalent in regions of the temperate zones where freshwater fish form an integral part of the diet  Common in N. Europe, N. America, Manchuria and Japan and S. America  Has been reported in man once from the Phils. D. latum: Morphology  Adult worm  Ivory or grayish yellow  Length – 3-10m  Number of proglottids – 3,000  SCOLEX  Spatulate, almondshaped  2-3mm by 1 mm

Micro/PARA – Cestodes by Dra. Bunyi

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 N rostellum nor hooklets  2 deep dorsoventral suctorial grooves called bothria Neck – unsegmented, several times the length of the scolex Mature proglottid  Broader than long  Contains both male and female reproductive organs  Characteristic morphologic feature – dark rosette-like coiled uterus at the center Ripe or gravid proglottid – same as mature proglottid Ova  Yellowish brown  Measures 5576µm by 4156µm  Inconspicuous operculum at one end  Small knob-like thickening at the other end  Contains plenty of yolk cells  Immature when oviposited D. latum: Life cycle

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 Infective stage to man and other hosts –  1.

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     D. latum: Epidemiology  The final hosts are man and other piscivorous mammals such as dog, cat, leopard, foxes, mink, pig, bears  1st intermediate hosts – copepods of the Genus Diaptomus and Genus Cyclops  2nd IH – freshwater fish like pike, trout, salmon, whitefish, turbot and carp in the Phils.

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plerocercoid larva in the 2nd intermediate host Usual vehicle for transmission – raw, partially cooked or frozen fish eaten raw D. latum: Diagnosis Clinical  Tapeworm appetite, abdominal pain and anemia particularly in people living in endemic areas Laboratory  Demonstration of the characteristic egg I the stool using acid ether concentration technique D. latum: Treatment Niclosamide – 4 tablers (2g) chewed thoroughly I a single dose after a light meal Paromomycin – 1g every 4 hrs for 4 doses Praziquantel – 10mg per kg in a single dose Quinacrine HCl – 0.8g given over a half hour interval D. latum: Prevention Thorough cooking of all fresh water fish and used for human consumption Freezing of fish for 48 hrs at a temperature of -10oC Tasting of raw freash water fish while being prepared for the table should not be practiced Proper treatment and disposal of sewage Sparganosis NONBRANCHING SPARGANA Spargana or plerocercoid larva of several species of Spirometra (Diphyllobothrium) mansonoides – found also in humans Geographic Distribution Found in East and SE Asia, Japan, Indochina and to a lesser extent North and South America Morphology Elongated, ivory white ribbonlike larvae Has an antero-posterior polarity Pseudosucker Elongated like a small tapeworm No scolex and no defined proglottids Life cycle Similar to D. latum

Micro/PARA – Cestodes by Dra. Bunyi

Epidemiology  The final hosts are dogs and cats  The first intermediate hosts are the copepods of the Genus Cyclops  The 2nd IH are the frogs, lizards, snakes, birds and monkeys  Man is an accidental IH  The infective stages are:  Porcercoid larva in the Cyclops  Plerocercoid larva (spargana) in the tissues of cold blooded vertebrates  Human infection results from:  Ingestion of Cyclops infected with procercoid larva  Ingestion of raw flesh of cold blooded animals harboring thespargana  Local application of the flesh of cold blooded vartebrates harboring the spargana Pathogenesis and Symptomatology  Found in any part of the body especially:  Eyes  Subcutaneous and muscular tissues of the thorax  Abdomen  Thighs  Inguinal region  Thoracic vertebra  Elongating and contracting larvae within a slimy matrix cause an inflammatory and painful edema of the surrounding tissue  Degenerated larvae cause intense local inflammation and necrosis but no fibrous tissue formation  Infected persons may show:  Local indurations  Periodic giant urticaria  Edema  Erythema accompanied by chills, fever and high eosinophilia

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 Ocular infection – painful edematous conjunctivitis with lacrimation and ptosis Diagnosis  By finding the larvae in the lesion Treatment  Surgical removal of the larval plerocercoid Prevention  Only potable water should be drank  Raw water from streams should be avoided as this may contain infected Cyclops  Use of cold blooded vertebrates as poultices should be avoided  Cold blooded vertebrates when eaten should be in a cooked state Sparganosis B. BRANCHING SPARGANA  Budding larval tapeworm – Spirometra proliferum Geographic Distribution  Reported in Japan and US Morphology  LARVA – irregular, lateral, supernumerary processes that may bud off as new spargan in the tissues Life cycle  unknown Diagnosis  Finding the larvae in the chylons nodular lesions Echinococcus  Disease caused by the larval stage which is acquired when eggs are ingested  E. granulosus – causes hydatid cysts  E. multilocularis – alveolar echinococcosis  Dogs and other canines are the most common definitive hosts E. granulosus (hydatid): Geographic Distribution

E. granulosus (hydatid): Morphology  ADULT WORM  3-6mm length  Possess pyriform, scolex, short neck and 3 proglottids (immature, mature, and gravid)  Hydatid cyst – usually measures 1-7cm in diameter  Consists of protoscolices

Micro/PARA – Cestodes by Dra. Bunyi

 The cysts (2-30cm) are constituted by

an external acellular cuticle and an inner cellular “ germinal” layer (1025µ) that produces the brood capsules containing 6-12 protoscolices or single protoscolices (Germinal layer with a protoscolex)  “Hydatid sand” – free protoscolices in

the cyst  Fluid aspirated from a hydatid cyst will show multiple protoscolices (size approx. 100µm), each of which has typical hooklets  The protoscolices are normally invaginated (left), and evaginate (middle, then right) when put in saline E. granulosus: Life cycle

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CNS * guys, di ko na mabasa yung nakalagay ulit kaya sensya na at incomplete to..dont know where they got this pero may i-aadd na lang ako from the net na siguro would describe whats supposed to be here.

 The symptoms, comparable to those of a slowly growing tumor, depend upon the location of the cyst. Large abdominal cysts produce increasing discomfort. Liver cysts cause obstructive jaundice. Peribronchial cysts may produce pulmonary abscesses. Brain cysts produce intracranial pressure and Jacksonian epilepsy. Kidney cysts cause renal dysfunction. The contents of a cyst may produce anaphylactic responses.     

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E. granulosus: Pathogenesis and Symptomatology  Pathology caused by developing larval cyst in the intermediate host  LIVER: most common and most important site of involvement (70%); 85% located in the right lobe Site Percentage of cases Abdomen Liver 75% Abdominal pain, hepatic mass, bile duct obstruction Lung 22% Chest pain, cough, hemptysis

E. granulosus: Diagnosis Endemicity Symptoms X-ray and CT scan Serology Skin (Casoni) test Serology Indirect hemagglutination (IHA), indirect fluorescent antibody (IFA) tests, and enzyme immunoassays (EIA)are sensitive tests for detecting antibodies in serum of patients with cystic disease Sensitivity rates vary from 60 – 90% Postivet reaction is confirmed by immunoblot assay or any gel diffusion assay that demonstrates the echinococcal “ Arc 5” Cansoni test An intermediate hypersensitivity skin test used to detect sensitization to hydatid

antigen E. granulosus: Treatment and Control  Surgical removal of cyst  Praziquantel  Avoidance or treatment of infected canine For inoperate cysts – PAIR (Puncture, aspiration, injection, reaspiration) E. multilocularis  Foxes are the natural definitive host  Small rodents are the IH  Humans infected by eating raw plants

Micro/PARA – Cestodes by Dra. Bunyi

contaminated with feces of infected canine or cats  Cyst wall – not clearly delineated from surrounding tissue; porous, spongy mass of small irregular cavities with a jelly like matrix Echinococcosis

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multilocularis: Treatmend and Control Surgical removal of the cyst Resistant to praziquantel Albendazole has some effect Avoidance control of rodent population