Travel Medicine

In Suspected Eosinophilic Meningitis Cases, Ask About Recent History of Travel to Hawaii

Jennifer J. Walker, MD, MPH; Nataliya Holmes, MD; and Jon Martell, MD

Walker JJ, Holmes N, Martell J. In suspected eosinophilic meningitis cases, ask about recent history of travel to Hawaii. Consultant. 2018;58(2):52.


When patients present with signs and symptoms that raise suspicion for meningitis, primary care providers should ask about recent travel to Hawaii.

Infection with larvae of the rat lungworm, Angiostrongylus cantonensis, is the most common cause of eosinophilic meningitis in southern Asia and the Pacific islands.1 According to unpublished data for patients treated at our facility, Hilo Medical Center, at least 40 cases of eosinophilic meningitis attributed to the parasitic nematode have been diagnosed on Hawaii Island since 2009.

Eosinophilic meningitis presents with signs and symptoms that range from mild headache and paresthesia to cranial nerve abnormalities, ataxia, coma, and rarely death. Symptoms present 1 week to 1 month after ingestion of larvae, the most common vectors of which are paratenic hosts such as snails and slugs, as well as uncooked and unwashed vegetables and untreated water sources. Presumptive diagnosis is based primarily on a patient’s clinical presentation, with a history of possible larvae consumption during travel to endemic regions.2 Confirmation requires lumbar puncture (LP), with results of cerebrospinal fluid analysis demonstrating eosinophilia of 10% of total nucleated cells, or an absolute eosinophil count of 10 or cells/µL.3 Antibody response may be noted during convalescence, and reliable serological tests are being developed and validated.4

Mild cases of eosinophilic meningitis attributed to infection with A cantonensis resolve spontaneously, and mild symptoms are treated with rest and over-the-counter pain medications. Treatment of more severe cases is controversial. Theoretically, the use of anthelmintic medications could trigger an immune response to dying larvae. However, medical providers in Hawaii have had favorable clinical outcomes using protocols that include albendazole, based on similar regimens that have been successfully used in Southeast Asia.5 More moderate disease symptoms, including headache or neuropathic pain severe enough to interfere with daily activities, are treated with therapeutic LP, systemic corticosteroids, pain medications directed at neuropathic pain, and supportive care; patients are given the option of using albendazole. Patients with severe symptoms are treated with serial LP, systemic corticosteroids, albendazole, pain medications directed at neuropathic pain, and prolonged supportive care.

Prevention of angiostrongyliasis emphasizes food hygiene.6 Vegetables that are eaten raw and unpeeled should be thoroughly inspected and carefully washed. Any vegetable with visible indication of snail or slug infestation should be peeled, cooked, or discarded. Freshwater fish and shellfish can be paratenic hosts for A cantonensis and should be cooked thoroughly before consumption. Water hygiene includes boiling any catchment water to be consumed and considering safer drinking water sources.

Hawaii Island residents are encouraged to attend to A cantonensis vector control. Rat infestations should be eradicated, and slug and snail populations should be discouraged. 

Jennifer J. Walker, MD, MPH, is the medical director of the Hawaii Island Family Health Center and a faculty member of the Hawaii Island Family Medicine Residency in Hilo, Hawaii.

Nataliya Holmes, MD, is a resident physician in the Hawaii Island Family Medicine Residency in Hilo, Hawaii.

Jon Martell, MD, is the medical director at Hilo Medical Center in Hilo, Hawaii.



  1. Martins YC, Tanowitz HB, Kazacos KR. Central nervous system manifestations of Angiostrongylus cantonensis infection. Acta Trop. 2015;141(pt A):46-53.
  2. Murphy GS, Johnson S. Clinical aspects of eosinophilic meningitis and meningoencephalitis caused by Angiostrongylus cantonensis, the rat lungworm. Hawaii J Med Public Health. 2013;72(6 suppl 2):35-40.
  3. Wang Q-P, Lai D-H, Zhu X-Q, Chen X-G, Lun Z-R. Human angiostrongyliasis. Lancet Infect Dis. 2008;8(10):621-630.
  4. Vitta A, Dekumyoy P, Komalamisra C, Kalambaheti T, Yoshino TP. Cloning and expression of a 16-kDa recombinant protein from Angiostrongylus cantonensis for use in immunoblot diagnosis of human angiostrongyliasis. Parasitol Res. 2016;115(11):4115-4122.
  5. Chotmongkol V, Kittimongkolma S, Niwattayakul K, Intapan PM, Thavornpitak Y. Comparison of prednisolone plus albendazole with prednisolone alone for treatment of patients with eosinophilic meningitis. Am J Trop Med Hyg. 2009;81(3):443-445.
  6. Angiostrongyliasis (rat lungworm). State of Hawaii, Department of Health, Disease Outbreak Control Division. Accessed January 10, 2018.