Gastropods

-

 Gastropods

P.K.Ghatak,MD

No 69.


Gastropod is a Greek word, which means mouth (gastrointestinal tract) in foot. Gastropod belongs to Mollusk phylum. The gastropod constitutes the largest family in the  Mollusum phylum, consisting of 80,000 species. They are grouped in 720 families and out of 720 families 250 are extinct. Among the living species 30,000 are marine, another 30,000 are terrestrial and the 5,000 are freshwater snail and slug species. Slugs are like sails without the external shell and most are nocturnal garden pests. Gastropods are hermaphrodites.


 

Snails are called Escargots in Latin and are a delicacy in France, Spain, Vietnam, Morocco and Algeria and other countries. The foot of the snail is an edible potion and is made up of proteins. The shell is not edible but the smaller the snail is, the more difficult it is to remove.

The largest in size and weight of this family is Conch. Australian trumpet (Syrinx aruanus) grows to 40 lbs. and reaches 3 ft in length. And the smallest species (Angustopila psamminon) found in caves in Vietnam is so tiny that 5 of them are required to match the size of a rice grain.


Gastropods live on vegetables, decaying animals and plants and feces. The mouth contains rows of sharp teeth. The record number of teeth is present in Banana slug, the total of 27,000 arranged in rows. Leeches resemble slugs and have sharp teeth, but leeches are not gastropods.


Nutritional value of gastropods. It is a good source of good quality protein, iron, calcium and vitamins.



Human diseases:

 Fresh water sails act as an intermediate host for the parasites. Each parasite has a specific class of freshwater sail that they use, where the parasite eggs hatch and molt and develop a free swimming infective form. Which in turn infects a secondary temporary host, usually crabs, crayfish or fish and sometimes hang on to the water vegetation. When people consume them raw or poorly cooked, these parasites develop into adult forms and begin shedding eggs or larvae in the urine, stool or sputum.

Initial symptoms are due to skin penetration and allergic reaction followed by variable intervals, depending on the worm, inflammation of the organ where the adult worm resides. 


1, Schistosoma.

Schistosomes are trematodes but sexes are separate, however males and females live in perpetual conjugation.

There are two main diseases caused by Schistosoma group.

A, S. haematobium: adult worms live in the small veins of the genito-urinary system of humans. Blood in urine is the main symptom and later develops cancers of the urinary bladder.


B, S. mansoni and S, japonicum: adult worms live in the veins of the portal system. Obstruction of portal circulation leads to gastrointestinal bleeding, liver cirrhosis and its complications.


2, Liver flukes, (Fasciola hepatica): unlike Schistosoma the Fasciola is a hermaphrodite and lives in the bile ducts. Obstruction of the main bile duct produces obstructive jaundice and cholangiocarcinoma.

The infective larva clings to water vegetation and crustacea and cover themselves with a protective coating like an egg. Humans and animals are infected by eating contaminated vegetation and crabs or shrimp.


3, Rat lungworm (Angiostrogylus cantonosis): It is a nematode(roundworm). Rats are the primary host and humans are accidental victims. The adult worm lives in rat lungs. Coughed up sputum is swallowed and eggs are passed in the feces of rats. Sails eat feces and infection spreads in the rat population. Humans are infected by eating raw or undercooked sails. The worms penetrate brain coverings and enter the brain and produce meningitis.


4, Oriental lung fluke. ( Paragonimus westermani):  Humans are infected by eating contaminated crab, crayfish and other crustacea.  Adult worms live in the lungs and produce signs and symptoms which resemble pulmonary tuberculosis.


#######################################################


Comments

Post a Comment

Popular posts from this blog

Eternity

-
The primary objective of this blog, Pari Talks blogspot. com is to draw out a smile from serious-minded science lovers, and no foul language is used.      l 'objectif principal de ce blog Pari Talks blodpsot.com est de tirer un sourire des amateus de science serie'ux, acun langage grossier n'est utilise'. Eternity PKGHATAK, MD No. 25. Eternity. Eternity means forever. Eternity is not limited by constraints of time and “everlastingness” means forever, but within the boundary of time. In ancient Egypt, the Pharaohs made elaborate arrangements for an eternal life after death. The pictorial writings on the walls of the secretive burial chambers and their elaborate funeral books tell their stories of how a pharaoh accumulated wealth and man-power for his comfort for eternity in the afterlife. It is said that as soon as a new pharaoh ascended to the throne, he would start collecting money, gold, and valuables for that purpose; not unlike the Washington congressmen who s...
Read more

Arsenic

-
  The primary objective of this blog, Pari Talks blogspot.com , is to draw out a smile from serious minded science lovers. Above all, no foul language is used. L'objectif principal de ce blog Pari Talks blodpsot.com est de tirer un sourire des amateus de science serie'ux, acun langage grossier n'est utilise'. Arsenic. P.K.Ghatak, MD No. 5 Agatha Christi used arsenic 14  times in her crime stories. Arsenic is an often-used poison to murder opponents in many other countries besides the U.K., and not only in stories but also in practice. Here are some infamous stories of murder by arsenic poisoning. King Mithridates VI, who ruled a land, now known as Turkey, from 120 to 60 BCE, was the first recorded history of an arsenic poison victim. A 4th-century  Roman emperor, Nero ,  murdered his stepbrother with arsenic to eliminate a serious rival to the Roman throne. The second-to-last emperor of the Qing dynasty ate a bowl of yogurt, and a few hours later, he...
Read more

Cult

-
   Cult PKGhatak, MD No.26 The last presidential election in the USA has given all three equal branches of the government to one political party. To the supporters of the other party and a section of independent-minded people, see this as an opening of a cult like atmosphere to develop in the US. The Supreme Court, by a large measure, allowed the recent curtailment of rights of the residents advanced by the administration to stay in place in the name of a timely review at a later date. The question should be raised about what one means by cult and are there have been any past incidents when cult culture caused great harm to human society. The rise of Hitler in Germany and Mussolini in Italy, and their coming to power, led to the beginning of WW II, which is a testimony to the evil effects that cult culture and its adherent followers can do to human society. If we study the recent incidents of cult movements in the USA, we can find why and how leaders of cults come to pow...
Read more