Human infection by Angiostrongylus cantonensis occurs through consumption of raw or undercooked food and vegetables that contain larvae or eggs of this parasite [1]. Rats or monitor lizards are primary hosts that shed the parasite through feces, while snails, prawns, freshwater shrimps, fish and crabs (depending on the geographic area) serve as paratenic (intermediate) hosts [1] [2] [3]. The Pacific and the Carribean islands, Latin America and Southeast Asia are considered to be the endemic regions of this parasite, but sporadic cases in travelers and the local population have been reported worldwide [3] [4]. The incubation period of infection may be quite long, ranging from several days to several months [4], and three clinical syndromes have been described - central nervous system (CNS), ocular and gastrointestinal infection [1] [3] [4] [5] [6]. Eosinophilic meningitis is a term used to describe the main subtype of infection, and presents with acute severe headaches, whereas seizures and acute loss of consciousness and even coma are typical for eosinophilic encephalitis, a more dangerous, and even fatal form of the disease [5]. On the other hand, blurred vision may be the only symptom of ocular angiostrongyliasis [7]. Gastrointestinal infection manifests as relapsing abdominal pain, tenderness, vomiting, fever (although rare), and a mass in the right lower abdominal quadrant, which may often mimic appendicitis or intestinal perforation [4] [6].

• Unconsciousness

  CNS symptoms begin with mild cognitive impairment and slowed reactions, and in a very severe form often progress to unconsciousness. Patients may present with neuropathic pain early in the infection. [en.wikipedia.org]

  The CNS symptoms begin with mild cognitive impairment and slowed reactions, and in very severe cases can progress to unconsciousness. Patients may present with neuropathic pain early in the infection. [diagnose-me.com]

• Fatigue

  Headache, myalgia and fatigue were the most common symptoms. Blood samples from 5 patients were positive for antibodies to A. cantonensis. [ncbi.nlm.nih.gov]

  Blastomycosis Botulism Brain abscess Brucellosis Bunyaviridae infections misc Campylobacteriosis Candidiasis Capillariasis intestinal Chancroid Chlamydia infections misc Chlamydophila pneumoniae infection Cholecystitis cholangitis Cholera Chromomycosis Chronic fatigue [books.google.de]

  Typical symptoms in children include fever, abdominal pain, vomiting, irritability, poor appetite, muscle weakness, fatigue, and lethargy. Lumbar puncture (LP) is an essential part of the evaluation of suspected neuroangiostrongyliasis. [health.hawaii.gov]

• Pathologist

  Pathologists from endemic regions (Central and South America) are familiar with the typical histologic changes; however, because of increasing global travel, all pathologists should become familiar with A costaricensis, which may mimic common gastrointestinal [ncbi.nlm.nih.gov]

  PCR might help in the diagnosis of abdominal angiostrongyliasis, particularly when the pathologists are not experienced with such disease. [journals.plos.org]

• Aspiration

  Tests for parasite-specific immunoglobulin G (IgG) antibodies are reliable. [ 4 ] Management Eosinophilic meningitis There is no effective curative treatment. [ 5 ] Treatment is supportive, including adequate analgesia, therapeutic CSF aspiration and [patient.info]

  The nematode was removed intact using an irrigating/aspirating cannula through a paracentesis. The patient was treated with Gt Pred forte 1% 2 hourly, Gt Chloramphenicol four times a day, and Gt Levobunolol twice daily. [nature.com]

• Nausea

  Patients presented with headache (100%), neck stiffness (20%), fever (40%), nausea (87%), vomiting (73%), paresthesia (7%), and muscle weakness (7%). [ncbi.nlm.nih.gov]

  Infection first presents with severe abdominal pain, nausea, vomiting, and weakness, which gradually lessens and progresses to fever, and then to central nervous system (CNS) symptoms and severe headache and stiffness of the neck. [en.wikipedia.org]

  Patients develop a severe headache, fever, neck stiffness, nausea, vomiting and abnormal nerve sensations. The worms may spread into the eye and cause blindness. CT and MRI scans may show the presence of worms in brain. [afairgo.net]

  He denied changes in visual acuity, discharge, pain, or systemic concerns (eg, headache, fever, nausea/vomiting, or nuchal rigidity). He denied traveling out of the country and contact with animals or animal feces, although he did note he ate sushi. [jamanetwork.com]

  Typical symptoms in adults include severe headaches, neck stiffness, nausea, paresthesias, and limb pains. [health.hawaii.gov]

• Abdominal Pain

  The authors describe a case of abdominal angiostrongyliasis in an adult patient presenting acute abdominal pain caused by jejunal perforation. [ncbi.nlm.nih.gov]

  Abdominal angiostrongyliasis This presents with acute abdominal pain in the right lower quadrant, associated with prolonged fever, anorexia and eosinophilia. Infection usually involves the terminal ileum, appendix or ascending colon. [patient.info]

• Severe Abdominal Pain

  Infection first presents with severe abdominal pain, nausea, vomiting, and weakness, which gradually lessens and progresses to fever, and then to central nervous system (CNS) symptoms and severe headache and stiffness of the neck. [en.wikipedia.org]

  Signs and Symptoms Infection first presents with severe abdominal pain, nausea, vomiting, and weakness, which gradually lessens and progresses to fever, and then to CNS symptoms and severe headache and stiffness of the neck. [diagnose-me.com]

• Hepatosplenomegaly

  We present a case of a 4-year-old girl with abdominal angiostrongyliasis who presented with persistent fevers, hepatosplenomegaly, acute abdominal pain, and eosinophilia. [ncbi.nlm.nih.gov]

  Abstract We present a case of a 4-year-old girl with abdominal angiostrongyliasis who presented with persistent fevers, hepatosplenomegaly, acute abdominal pain, and eosinophilia. [journals.sagepub.com]

• Visual Impairment

  Inflammation resolved with topical corticosteroid and antibiotic treatment, but visual impairment persisted. [ncbi.nlm.nih.gov]

• Retinal Pigmentation

  She also had retinal pigment epithelial disturbance with focal intraretinal haemorrhage. The 19.9 mm worm was surgically removed and identified as Angiostrongylus cantonesis. She was treated with oral mebendazole. [ncbi.nlm.nih.gov]

  The fundus examination revealed generalized retinal pigment epithelial alteration, subretinal tracks, retinal oedema, macular oedema, and a pale disc. [nature.com]

• Anterior Uveitis

  In addition, anterior uveitis with 2 inflammatory cells together with a live worm ( Figure 1 ) was noted in the right eye. Intraocular pressure in the right eye was elevated at 34 mmHg. [nature.com]

• Negativism

  The study shows indications that abdominal angiostrongyliasis is usually not a persistent infection: although serological negativation may take many months, IgG reactivity is usually declining along time and serum samples pairing may add valuable information [ncbi.nlm.nih.gov]

• Headache

  Compared with the controls, the patients given the combination were less likely to have headaches after 7 days (P 0·038), tended to have headaches that cleared quicker (P 0·010), and received fewer doses of acetaminophen (P 0·036). [ncbi.nlm.nih.gov]

  Median duration of headache was 3 days; 8% had headache; no serious side-effects. 28 34 (age 15) Albendazole (15 mg/kg). Mean duration of headache was 8.9 days; 21% of headaches persisted; no serious side-effects. 32 (age 15) Placebo. [antimicrobe.org]

• Areflexia

  Eventually, severe infection will lead to ascending weakness, quadriparesis, areflexia, respiratory failure, and muscle atrophy, and will lead to death if not treated. [en.wikipedia.org]

  Cases of severe infection will eventually lead to increasing weakness, tetraparesis, areflexia, respiratory failure, and muscle atrophy – and to death if not treated. [diagnose-me.com]

• Mild Cognitive Impairment

  CNS symptoms begin with mild cognitive impairment and slowed reactions, and in a very severe form often progress to unconsciousness. Patients may present with neuropathic pain early in the infection. [en.wikipedia.org]

  The CNS symptoms begin with mild cognitive impairment and slowed reactions, and in very severe cases can progress to unconsciousness. Patients may present with neuropathic pain early in the infection. [diagnose-me.com]

• Papilledema

  Ophthalmologic fundoscopy showed that 25.0% with papilledema which was significantly higher than seen in adults (12%) in Thailand. [ncbi.nlm.nih.gov]

  Ophthalmologic fundoscopy showed 25.0% with papilledema, which was significantly higher than seen in adults (12%) in Thailand. [popline.org]

• Hyporeflexia

  The ensuing illnesses began within 1-6 days, persisted up to 10 weeks, and were characterized by both peripheral blood and spinal fluid eosinophilia, severe pains, weakness and hyporeflexia of the legs, and dysfunction of the bladder and bowels. [ncbi.nlm.nih.gov]

The diagnosis of angiostrongyliasis may be difficult to attain, given the fact that the incubation period may be quite long, but the majority of studies have confirmed that symptoms develop in a matter of weeks after ingestion of the parasite [3] [4]. Having in mind these findings, an adequately obtained patient history may be the most valuable procedure in the diagnostic workup, during which information about recent travel and possible consumption of foods that could have been contaminated by parasitic eggs or larvae are obtained. Severely ill patients (especially those suffering from CNS infection) may not be able to provide such data, requiring additional tests to confirm angiostrongyliasis as the underlying cause. The terms "eosinophilic meningitis" and "eosinophilic encephalitis" are used because lumbar punctures reveal a high eosinophil count in the vast majority of patients since eosinophils are produced in the defense against parasitic infection [3]. Although serological testing for this parasite exists, being both highly specific and sensitive [3], its availability is scarce [5], implying that the diagnosis rests on patient data and results from lumbar punctures. Some patients may be diagnosed post-operatively when histopathological examination of the removed tissue reveal the presence of parasites, and so far, the gastrointestinal system, but also the liver and the testes, were organs from which the parasite was isolated [4].

1. Wang QP, Wu ZD, Wei J, Owen RL, Lun ZR. Human Angiostrongylus cantonensis: an update. Eur J Clin Microbiol Infect Dis. 2012;31(4):389-395.
2. Wang QP, Lai DH, Zhu XQ, Chen XG, Lun ZR. Human angiostrongyliasis. Lancet Infect Dis. 2008;8:621–630.
3. Lv S, Zhang Y, Chen SR, et al. Human Angiostrongyliasis Outbreak in Dali, China. PLoS Negl Trop Dis. 2009;3(9):520.
4. Kramer MH, Greer GJ, Quiñonez JF, et al. First reported outbreak of abdominal angiostrongyliasis. Clin Infect Dis. 1998;26(2):365-372.
5. Sawanyawisuth K, Takahashi K, Hoshuyama T, et al. Clinical factors predictive of encephalitis caused by Angiostrongylus cantonensis. Am J Trop Med Hyg. 2009;81(4):698-701.
6. Mandell GL, Bennett JE, Dolin R. Mandel, Douglas and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, Pennsylvania: Churchill Livingstone; 2015.
7. Sinawat S, Sanguansak T, Angkawinijwong T, et al. Ocular angiostrongyliasis: clinical study of three cases. Eye (Lond). 2008;22(11):1446-1448.