Tapeworms to’adulthood

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PLATHELMINTHES (tapeworms)

  • elongated flattened body dorsoventrally bilaterally symmetrical
  • deformable soft integument (protection, respiratory and metabolic exchange) lined internally by a muscular layer
  • general cavity filled by mesenchymal (breathing role, storage and excretion of nutrients)
  • respiratory and circulatory systems absent
  • excretory apparatus : protonephridia and tubular system
  • Male and female reproductive apparatus present in each ring : tapeworms are hermaphroditic.

Phenomenon protérandrie (large tapeworms)

  • Device missing digestive (cestode), incomplete (tréniatode)
  • Towards banded and segmented dishes, whose body is divided into 3 parties :

+ Un scolex : front part which carries the attachment members.
+ A neck : growth area = rings
+ A body or strobilus: formed by a string of identical structure segments (proglottis).

  • rings : bags muscular wall, parenchymatous filled with’male and female genitals; apparatus excretory and nervous system.
  • Endo- all adult stages, they parasitize vertebrates (specifically the digestive tract)

  • The larvae are parasitic on vertebrates and d’invertebrates.

General morphology of adults :

  • banded body
  • scolex (head) with fasteners (suction cups, hooks, bothridies)
  • cou : zone de formation des proglottis
  • strobile (chain of « rings » or proglotti or segments)

The criteria for differentiating tapeworms deal : (between Cyclophyllidés and Pseudophyllidea) :

+ The fasteners
+ The lateral position or median of the genital pore
+ Whether or not d’a bridge hole
+ Name D’intermediate hosts

1- Cyclophyllidae :

Scolox : Piriforme, 4 suction cups, sometimes hooks arranged in 1, 2 Proglottids or more crowns : Pore ​​side genital ; Orifice of missing egg. 1 HI

2- the Pseudophyllidea :

Scolox : Elongate, 2 bothridies
Proglottis : Pore ​​average ventral génital ; Orifice medium ventral bridge. 2HI

I- Taenia saginata (Taenia of cattle tapeworm or unarmed) :

  • HD : men -HI: cattle
  • Big size (4 at 12 m in length)
  • generally isolated (tapeworm)
  • Lifetime : 5 a 25 years
  • cosmopolitan distribution

Morphology :

Adult :

– Flatworm banded, pearly white
– Scolex piriforme de 1 at 2 mm,
– fastener : 4 suction cups (or face, or hooks) d’or « Defenseless Ténia »
– strobe 4 at 10 m, 1000 at 2000 « rings » or segments,
– genital pores : alternated irregularly
– uterine fine ramifications, and many dichotomous (after dyeing)

mature segments :

– rectangular (15 at 20 mm x 5 at 7 mm) with numerous fine uterine branches; > 15 (Ramifications dichotomiques)
– mature segment contains more than 50 000 eggs
– Walls + long than wide rings

Egg : embryophore

– rounded, 40 pm, thin outer shell ; easily torn, and often absent, thick inner shell, brown and struck.
– Contains an embryo « hexacanthe » (at 6 chitinous hooks)
– The embryonated eggs are very resistant (more than 6 months in the ground) and better withstand the cold than the heat

> The cycle :

Larve cysticerque (Cvsticercus bovis) :

– It results from the development of hexacanth embryos within’favorite organs in’intermediate host, after ingestion and migrate through blood or lymphatic.

– filled vesicle translucent liquid, from 5 at 20 mm, containing a small invaginated scolex This larva s’encyst and can live like this for several years before degenerating and calcifying.

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> Clinique :

– usually asymptomatic,
– If not : taeniasis (Digestive disorders ; Asthenia ; Anorexia or Bulimia ; neurological disorders (child) ; various allergic manifestations (pruritus, urticaria) ; exceptional complications)

> Diagnostic direct :

1- Discovery of the rings in the clothes, bedding :
Coloration (carmine red) : viewing the uterine branches, position genital pores
2- Search eggs in feces
• direct microscopic examination
• Review after concentration
3- Scotch test anal: scotch test de GRAHAM
4- Search copro Ag Elisa : specify l’species (T.saginata, T.solium)
5- Molecular biology : PCR: distinguish 2 cash

> Treatment :

Praziquantel ou Biltricide® 10mg / Kg in a single dose
Niclosamide or Trédémine® 2g at ​​l’adult, half or a quarter at home’child It requires a very specific method of taking to be effective : remain fasting from the day before ; to take 2 tablets after chewing them for a long time and swallowing with a little’water ; wait 1 hour without power, take two tablets as above and then wait again 3 hours before s’feed.

> Prophylaxis :

– The fight against fecal peril
– well-done meat consumption (infective forms are rapidly killed at a T ° more 60 °C) frozen or otherwise prior to -10 ° C for 10 days or days between 10-20 °C

II- tape seat :

– cosmopolitan distribution except Muslim and Jewish countries
– taenia pork or Taenia armed -HD : -HI men : pigs
– 2 at 4 meters long (shorter than saginata)
– Sometimes, multi parasitism (2 at 10 towards)
– Lifetime : 5 at 25 years

*differance between the tape and Fasciola set to flourish

Scolex (suckers without hooks) Scolex (suction cups with hooks)
Egg no difference Egg no difference
Ramifications many uterine Ramification uterine few
genital pores irregularly alternate genital pores regularly alternate
rings : Stand alone force the anal sphincter rings : Stand by 5 or 6 Knocked out during bowel movements
global distribution Beef (intermediate host) intertropical distribution Pig (intermediate host)
L’man can not be intermediate host
L’man may be intermediate host

 

> Cycle indirect dixène :

HD = man (possibility of’host several adult worms at the same time), anal passive output ripe segments with the feces (from 5 at 30 per day)
HI = pig; larve cysticerque = Cysticercus cellulosae
• L’man s’infested by :
– pork consumption parasitized by the cysticercus larva : then it is HD -> Taeniasis
– ingestion d’embryophores d’human origin or digestion of mature segments in the intestinal lumen : it is then HI -> cysticercose humaine

> Geographical distribution :

– Taenia solium is common in tropical countries (Madagascar, South America, Far East), also present in some countries of’Europe (Italy, Spain, country of’East)

– Little or Taenia solium in Muslim and Jewish countries

III- Hymenolepis nana :

Adult : C’is the smallest cestode of the’intestine’man 10 at 30 mm x 1 mm
Scolex : 4 suckers and short rostrum, armed retractile’a crown of hooks ;
The strobilus about 200 rings. (Broader than long).

Egg : ovoid embryophore, 45pm, embryo hexacanth, thin outer shell, thick inner shell at two polar nipples, filaments between the apical 2 membranes

> Cycle :

Cycle direct court :

  • HD = man, hosts hundreds of parasites. Eggs issued in feces are directly infesting. Swallowed by’man, they will hatch in the duodenum, releasing hexacanth embryo which is fixed in the intestinal mucosa, becomes cysticercoid larva and adult

occasional indirect cycle :

  • HI = insects (see farine, wog, puce), l’egg is swallowed will hatch and turn into a cysticercoid larva. l’man especially l’child s’infested by accidental ingestion of such parasitic insects.

IV- DiphyUobothrium large;:

Morphology :

– Cestode large 1 at 12 up’at 20m
– Color : smoky gray

Adult :

– 3000 at 4000 trapezoidal segments (broader than long)
– scolex : 2 bothridies, elongate; a ventral and l’other backbone
– PG : Median

Egg :

– 70 x 45 pm, ovoid squat (aspect d’chicken egg),
– Cap at one pole
– shell smooth thin light yellow,
– contains many cells (anembryonic for laying)

> Cycle :

> Fashion contamination :

Infestation is achieved by eating undercooked fish, smoked

> Geographical distribution :

Botriocephalosis occurs in all lake regions of the world where the’man eats raw or undercooked fish (Europe, USA, Asia)

> Clinique :

– taeniasis
– Anemia vitamin B12 deficiency such pernicious.

> Diagnostic :

– Parasitological examination of stools :
+ direct examination
+ Review after concentration
– Eggs bothriocéphale

> Treatment :

Niclosamide
Praziquantel
*Vitamin B12 deficiency is easily corrected, either spontaneously more often, either vitamin B12 supplementation if necessary after removal of the parasite.

> Prophylaxis :

  • health Education : consumption of properly cooked fish
  • Fight against faecal danger avoiding contamination of the’water.
  • The fish can be salted (sodium chloride 12 % pendant 15 days), or heat-treated (55 °C) or cold (-10 °C).
  • So, conservation in the freezer for 1 week is effective.

Course of Dr Ahraou – Faculty of Constantine