Anisakiasis is a rare parasitic disease which occurs when the larvae of the nematode Anisakis are ingested by humans through raw or undercooked fish or squid [1] [2]. The larvae invade the gastrointestinal lining leading to the symptoms of anisakiasis. The highest incidence of the illness has been reported to be in winter [3] due to the high consumption of raw fish in that season. The symptoms depend on the site invaded by the larvae and can be classified as gastric, intestinal, and ectopic anisakiasis [1] [4] [5]. A majority of the patients have gastric anisakiasis.

Symptoms of gastric anisakiasis typically start within 12 hours of ingestion of infected raw fish or squid [3] while those of intestinal anisakiasis have been reported to occur up to a week after ingestion [1] [6]. The commonest symptom is sudden onset severe abdominal or epigastric pain resembling an acute abdomen. This is accompanied by nausea and vomiting. Intestinal anisakiasis can present with symptoms resembling Crohn's disease with an inflammatory mass. Other reported presentations include severe hematemesis in patients with gastric ulcer and hemoptysis [3] [7] [8] [9] [10]. The Anisakis larvae do not survive for long in the human gastrointestinal tract and therefore the symptoms subside in a couple of weeks with medical management [11]. However, a few cases of intestinal strangulation and obstruction requiring surgical intervention have been reported [12] [13].

• Fever

  The warning from doctors came after they provided treatment to a 32-year old healthy man who had severe epigastric pain (pain in the upper abdomen), vomiting, and fever for a week. [news-medical.net]

  A 22-years-old man living in Hyuga City, Miyazaki Prefecture, Japan, developed high fever, respiratory distress, and pleural effusion after consumption of raw fish. [ncbi.nlm.nih.gov]

  Gastroenterology, Hospital da Luz, Lisboa, Portugal Correspondence to Dr Joana Carmo, joanavcarmo{at}gmail.com Statistics from Altmetric.com Description A previously healthy man, aged 32 years, was admitted with severe epigastric pain, vomiting and low-grade fever [casereports.bmj.com]

  Symptoms include Abdominal pain, nausea, vomiting, abdominal distention, diarrhea, blood and mucus in stool, and mild fever Treatment can be done by endoscopy or surgery by removing worms from the body [omicsonline.org]

  Symptoms of anisakiasis include nausea, vomiting, abdominal distention and pain, diarrhea, blood and/or mucus in the stool, and fever. Allergic reactions can also occur. [medicinenet.com]

• Pathologist

  Clinicians and pathologists should be aware of this unusual parasitic infestation in this country. [ncbi.nlm.nih.gov]

  Based on the gross and microscopic characteristics as well as the clinical presentation of acute abdominal pain, a diagnosis of intestinal anisakiasis was made by the pathologist (JPB). Figure 3. [academic.oup.com]

• Chest Discomfort

  Acute gastric anisakiasis with severe chest discomfort is rarely reported in Italy. [ncbi.nlm.nih.gov]

  Conclusions In our reported case, the chest discomfort described by our patient was so severe that the patient was admitted in our Emergency Department. [oatext.com]

• Splenectomy

  Surgical treatment was performed successfully and consisted of excision of the gastric lesion and splenectomy. [ncbi.nlm.nih.gov]

• High Fever

  A 22-years-old man living in Hyuga City, Miyazaki Prefecture, Japan, developed high fever, respiratory distress, and pleural effusion after consumption of raw fish. [ncbi.nlm.nih.gov]

• Respiratory Distress

  A 22-years-old man living in Hyuga City, Miyazaki Prefecture, Japan, developed high fever, respiratory distress, and pleural effusion after consumption of raw fish. [ncbi.nlm.nih.gov]

• Vomiting

  Given the non-specific clinical presentation of acute abdomen, nausea, and vomiting these patients are often subject to radiologic imaging. [ncbi.nlm.nih.gov]

  If misdiagnosed, it can become chronic, with intermittent abdominal pain, nausea and vomiting lasting from weeks to several years. [orpha.net]

• Abdominal Pain

  The 1st patient was a 48-year-old female presenting with abdominal pain. An abdominal computed tomography scan showed a dilated small intestine and accumulation of ascites. [ncbi.nlm.nih.gov]

  pain, nausea, diarrhea Raw clams 2–3 days CT 4 days Ex lap, SBR Distal ileum Yes/Yes Yes Takano (2013) 63/M Abdominal pain, vomiting Raw fish 2 days AXR, CT NA Nonoperative therapy with ileus tube Small bowel NA NA Kojima (2013) 61/M Abdominal pain NA [academic.oup.com]

• Nausea

  Given the non-specific clinical presentation of acute abdomen, nausea, and vomiting these patients are often subject to radiologic imaging. [ncbi.nlm.nih.gov]

  vomiting Raw fish 2 days AXR 3 days Ex lap, appendectomy Terminal ileum NA/Yes Yes Kang (2010) 60/F Abdominal pain, nausea, fever Raw fish 1 day AXR, CT 1 day Ex lap, SBR Jejunum NA/Yes Yes Masui (2006) 51/F Abdominal pain, nausea, vomiting Raw fish [academic.oup.com]

• Acute Abdomen

  We suggest that anisakiasis should be considered in the differential diagnosis of patients with acute abdomen. [ncbi.nlm.nih.gov]

• Diarrhea

  A 69-year-old man was admitted for abdominal pain, diarrhea, and urticaria. Right hemicolectomy was performed because of an obstruction of the ascending colon and a palpable tumor of the right lower abdomen. [ncbi.nlm.nih.gov]

  The chronic intestinal symptoms include weight loss, mild cramping, abdominal pain, and diarrhea, lasting for months or years. [orpha.net]

• Urticaria

  Infection with Anisakis causes a wide spectrum of clinical manifestations, ranging from symptoms related to the upper and occasionally lower digestive tract to allergic manifestations, mainly urticaria and anaphylaxis. [ncbi.nlm.nih.gov]

• Chronic Urticaria

  IgE sensitization to Anisakis pegreffii in Italian subjects suffering from gastro-allergic anisakiasis (GAA) (N 5), or showing chronic urticaria (CU ) after fish consumption (N 100), was investigated. A control group (N 5) was also included. [ncbi.nlm.nih.gov]

Clinical suspicion is very vital in the work up for anisakiasis. The first step in the diagnosis is to obtain a history of ingestion of raw or undercooked fish or squid, if possible, as patients may forget details about their meals. After a thorough physical examination, the next step is to order routine laboratory tests like complete blood count, erythrocyte sedimentation rate, serum electrolytes and stool test for larvae, although stool test is not useful in most cases.

Currently, upper gastrointestinal endoscopy forms the mainstay of the diagnosis and requires accurate interpretation of the clinical images to identify the causative worm sticking to the stomach wall. Intestinal anisakiasis is difficult to diagnose as the small intestine cannot be accessed with the endoscope [14]. Capsule endoscopy or double balloon endoscopy may not be available universally. Another method to diagnose anisakiasis is by examining Anisakis-specific immunoglobulin (Ig) A, IgG, and IgE. These tests have a high sensitivity [15] [16] but do not provide results immediately and are therefore not useful in practice.

Radiological tests can help to confirm the diagnosis of anisakiasis. On ultrasonography, features of anisakiasis include severe localized Kerckring’s fold edema (corn sign), and dilatation of the proximal small intestine with the accumulation of fluid [14]. Computed tomography scan findings show partial small bowel edema and dilatation of the small intestine with fluid collection on the cranial side of the lesion [12] [17] [18].

• Pneumoperitoneum

  In the plain abdominal radiograph, pneumoperitoneum was evident; a computed tomography (CT) scan of the abdomen confirmed the presence of extraluminal air. Anamnesis disclosed the ingestion of raw fish during the week preceding her illness. [ncbi.nlm.nih.gov]

• Gastric Lesion

  Surgical treatment was performed successfully and consisted of excision of the gastric lesion and splenectomy. [ncbi.nlm.nih.gov]

• Colitis

  Untreated anisakiasis may cause persistent inflammatory responses targeting remains of the larvae and can produce symptoms consistent with colitis, appendicitis, cholecystitis, or dyspepsia (12). [antimicrobe.org]

The clinical suspicion with a correct diagnosis of anisakiasis allows the establishment of a correct treatment; in most cases, the resolution is possible with conservative treatment, avoiding unnecessary surgery to the preoperative differential diagnosis [ncbi.nlm.nih.gov]

One challenging issue in the diagnosis of anisakiasis is the molecular detection of the etiological agent even at very low quantity, such as in gastric or intestinal biopsy and granulomas. [ncbi.nlm.nih.gov]

Etiology Anisakiasis is caused by the ingestion of third stage larvae of Anisakid nematodes of the genus Anisakis, present in viscera or muscle of fish or cephalopods which are eaten raw, insufficiently cooked, smoked or marinated. [orpha.net]

Epidemiological data and clinical features were analysed. Particular attention was paid to the source of infection. In total, 73 cases were included in the analysis, while 34 were excluded. [ncbi.nlm.nih.gov]

Conclusion The present study is the first attempt to a better understanding of the epidemiological picture of anisakiasis in Italy, mining official data. [journals.plos.org]

Summary Epidemiology To date, more than 20,000 cases of anisakiasis have been reported worldwide, over 90% from Japan (2,000-3,000 cases reported annually), and the rest from the five continents: Asia (Korea), Europe (the Netherlands, Germany, France, [orpha.net]

Early diagnosis is very important as it could prevent unnecessary surgical procedures since the symptoms of intestinal anisakiasis may mimic other illnesses such as appendicitis, ileitis or peritonitis. [ncbi.nlm.nih.gov]

They're not cooking the fish so that is the only prevention method, keeping it cold," he said. [cbsnews.com]

Anisakiasis can be prevented with the following measures: Abstaining from eating raw fish or squid Adequately cooking or freezing fish before consumption (however, this does not necessarily prevent an allergic response): Proper cooking procedure recommends [dovemed.com]

Anisakiasis infection can be prevented by heating seafood to a temperature higher than 122 F (50 C), or freezing it to at least 4 F( 20 C) for at least 24 hours. Such actions kill the larvae. [encyclopedia.com]

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