ATLASINTESTINAL PARASITES (Helminths)
      NEMATODA Order: Ascaridata
      ANISAKIS SP.

      Courtesy of Dr Claudio Ghittino

      ani2-ic

        Definition  

      Anisakis sp.: Anisakiasis is a disease of the alimentary tract caused 
      by the nematode larvae belonging to the subfamily of Anisakinae. 
      Men become infected by eating raw or pickled fish. 
      The disease in men is caused by 3 types of anisakinae larvae: 
      Anisakis      , Phocanema, Contracaecum. 
      All infections in man have been caused by larval stage. 

      Macroscopic appearance of third stage larvae


      Courtesy of Dr Claudio Ghittino
      a) ani1-ic b) ani7-ic

      Life cycle and geographic distribution and epidemiology

      Anisakis sp.: The adults of the parasite live in the stomach 
      of marine mammals such as whales or dolphins. 
      Crustacean are the first intermediary hosts of Anisakis; 
      the second intermediary host includes various species 
      of seafishes and some cuttlefish. 
      The larvae are found on the surface or on the subserosa of viscera 
      and coiled in the cyst (A.type I larva), 
      but number of larvae occur in the musculature of codfish and salmon. 
      Larvae do not mature in man but attach to the mucosa (mainly of the stomach). 
      They may penetrate into or through the muscular coats of the gastrointestinal tract. Anisakis larvae are common parasites of sea mammals in the North Sea, 
      Atlantic and North Pacific oceans. 
      The human disease is frequently described in Scandinavia, 
      Japan (after eating sushi, sashimi), Holland (by eating herrings) Britanny 
      and along the Pacific coast os South America (by eating ceviche). 
      Infected fish are commonly marketed in many countries.

      a) Life cycle; 
       b) third stage larva, longitudinal section at higher magnification (H&E stain).


      Courtesy of Dr Claudio Ghittino

      Courtesy of Dr Claudio Ghittino

      a) ani3-ic

      b) ani4-ic

      Clinical features 

      Anisakis sp.: Symptoms vary according to individual susceptibility 
      and to the site of occurrence within the gastrointestinal tract. 
      About 2/3 of patients with anisakiasis have gastric lesions (acute or chronic). 
      Acute stomach anisakiasis occurs with sudden abdominal pain several hours 
      (about 12) after eating raw seafood and may mimic food poisoning, 
      acute gastritis or perforation of stomach ulcer or cholelitiasis. 
      Anisakis larvae can be seen directly by gastroscopy penetrating 
      the stomach wall and can be removed with the biopsy forceps. 
      Chronic anisakiasis of the stomach may mimic peptic ulcer, 
      chronic gastritis and gastric cancer.

      a) Third stage larva, section, 60X (H&E stain): 
      cuticule and muscle cells are visible; 
      b) Third stage larva, section, 160 X (H&E stain).


      Courtesy of Dr Claudio Ghittino Courtesy of Dr Claudio Ghittino

      a) ani5-ic

      b) ani6-ic

      Anisakis sp.:Intestinal anisakiasis often have more 
      severe symptoms and the disease can be serious. 
      Signs and symptoms may lead to a diagnosis of acute appendicitis, ileus, 
      intestinal invagination, acute peritonitis, gastric or intestinal perforation, 
      regional enteritis, and diagnosis is difficult before laparotomy. 
      Hemorrhagic ascites is usually observed and the intestin is thickened, 
      oedematous, with hemorrhagic spots on the serosal surface. 
      Enlarged lymph nodes are frequently observed.

      a) Section of a third stage larvae, 400 X (H&E stain); 
       b) third stage larva, longitudinal section (H&E stain).


      Courtesy of Dr Claudio Ghittino By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD.

      a) ani7-ic

      b) ani8-ic

      Patology

      Anisakis sp.: The gastric and intestinal wall appear oedematous, 
      and diffusely thickened in the segment involved. 
      Microscopically the lesions range from diffuse interstitial edema 
      with an eosinophilic infiltrate and well preserved parasites; 
      granulomatous lesions with foreign body giant cells and epitheliod cell 
      without well defined parasites may be seen in more advanced cases.

      a) Section of a third stage larvae, 400 X (H&E stain); 
      b) section of Anisakis larva in the intestinal wall (H&E stain)



      By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD.

      By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD.

      		 By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD.

      a) ani9-ic

      b) ani10-ic and ani11-ic
      By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD. By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD. By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD.

      c) ani12-ic and ani13-ic

      d) ani14-ic
      By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD. By Francesca Canta MD, Anna Maria Caputo MD, Alessandro Vitali MD, and Pietro Caramello MD.

      e) ani15-ic and ani16-ic


      Anisakis sp.:In human infected tissues larval anisakines
      (about 450-500 m m in diameter) are recognizable by:

      • a thick multilayered cuticle (Photo a);

      • the large lateral chords
        (about 90 m m in the figure) with a butterfly-like shape (Photo b)

      • many somatic muscle cells of polymyarial type in each quarter of worm
        (37 m m high in the figure) (Photo c);

      • an intestin lumen (260 m m in diameter in the figure)
        characterized by numerous tall columnar cells and a Y shaped lumen
        (not visible in all sections) (Photo b, c, d);

      • a large excretory gland cell in the anterior region;
        "renette cell" is banana-shaped in cross sections (Photo e).

      If the anterior region is lacking,
      classification as type may be difficult or impossible.

      Transverse section an Anisakis larva.
      The intestine and a small portion of the excretory gland cell is visible.


      Prevention

      Heating to 60° C or freezing at –20° C for more than 24 h. kills larval anisakines in fish. Health education should discourage the eating of raw or inadequately prepared fish.