Neuroangiostrongyliasis: Global Spread of an Emerging Tropical Disease

Abstract

Neuroangiostrongyliasis (NAS) is an emerging parasitic disease caused by the neurotropic nematode Angiostrongylus cantonensis. Since it was first discovered, in rats in southern China in the 1930s, this tropical to subtropical parasite has spread to much of Southeast Asia, the Pacific Islands (including Hawaii), Australia, Japan, South America, the southeastern United States, the Caribbean, Africa, the Canary Islands, and the Balearic Islands. The parasite completes its natural life cycle in snails and slugs (intermediate hosts), and rats (definitive hosts). Humans become accidental hosts after ingesting infective third-stage larvae contained within uncooked or undercooked intermediate or paratenic hosts, an event that sometimes results in NAS, also known as rat lungworm disease. Although A. cantonensis larvae cannot complete their life cycle in humans, their migration into the brain and spinal cord combined with a powerful inflammatory reaction often leads to eosinophilic meningitis and can, in rare instances, lead to coma, paralysis, and death or, in other cases, chronic, disabling neurologic sequelae. Symptoms of NAS are diverse, which often makes it difficult to diagnose. Treatment may include administration of analgesics, corticosteroids, anthelminthics, and repeat lumbar punctures to reduce intracranial pressure. Unfortunately, few medical providers, even in endemic areas, are familiar with A. cantonensis or its epidemiology, diagnosis, and treatment. As the parasite continues to spread and NAS affects more people, medical practitioners, as well as the general public, must become more aware of this emerging zoonosis and the potentially devastating harm it can cause.

Neuroangiostrongyliasis: Rat Lungworm Invades Europe

“…In light of these reports, continental Europe was considered threatened by this important zoonotic parasite. 1 Confirming this concern, the parasite has now been detected in the city of Valencia on the Spanish mainland. 5 Among 27 rats trapped, 29 adult A. cantonensis were found in four, from locations both near the port and several kilometers inland.…”

“…A recent short review in this journal 1 on the global spread of the rat lungworm, Angiostrongylus cantonensis (Nematoda: Angiostrongylidae), the cause of neuroangiostrongyliasis (NAS), noted that it had been reported recently in the Canary Islands 2 , 3 and Mallorca. 4 Both of these are Spanish territories, the former in the Atlantic Ocean off northwest Africa and the latter in the Mediterranean Sea, off the coast of Spain.…”

“…In light of these reports, continental Europe was considered threatened by this important zoonotic parasite. 1 …”

“…It was first discovered in 1933 in southern China and has now spread widely, primarily across the tropics and subtropics, as reflected in the distribution of human cases of NAS, which can be life threatening. 1 The only known autochthonous case of NAS in Europe was diagnosed in Paris in 2016; however, the source of this infection was never identified, as the patient had not traveled outside of France since the 1980 s other than to Morocco more than 2 years previously, and reported no consumption of possible hosts. 6 Otherwise, all cases diagnosed in Europe have been in travelers returning from endemic areas.…”

Angie-LAMP for diagnosis of human eosinophilic meningitis using dog as proxy: A LAMP assay forAngiostrongylus cantonensisDNA in cerebrospinal fluid

“…The 'rat lungworm' (Angiostrongylus cantonensis) is a nematode with a unique affinity for the central nervous system (CNS) found throughout the Asia-Pacific region, and more recently in the United States and Europe [1][2][3][4][5][6][7][8]. Currently, A. cantonensis is recognised globally as the leading cause of eosinophilic meningitis in humans, which is a serious condition observed when larvae migrate to the CNS [5,9,10]. It has been recorded as an etiological agent for meningitis in humans in at least 30 countries, including Australia, making it a parasite of increasing importance [11].…”