Spread of a parasite that causes meningitis

The parasite that is the most frequent cause of a type of meningitis has been found for the first time in rats from continental Europe.

The research in which this finding has been made is the work of a team that includes scientists from the University of Granada (UGR) in Spain. Specifically, the authors of the study have found the Angiostrongylus cantonensis worm in the pulmonary arteries of rats, a zoonotic parasite capable of being transmitted to humans and which is the most common causative agent of eosinophilic meningitis in people. This disease causes inflammation of the membrane that covers the brain and can cause seizures, brain damage and visual disturbances, among other symptoms.

The study, led by the Parasites and Health group of the University of Valencia and directed by Professor María Teresa Galán Puchades, involved researchers from the Biochemical and Molecular Parasitology Laboratory of the Institute of Biotechnology of the University of Granada, directed by Professor Antonio Osuna Carrillo de Albornoz. The researchers have located the parasite in two species of rats from the city of Valencia.

“To date, the nematode had only been detected at the island level in Europe (in rats from Tenerife and in sea urchins from Mallorca). Both globalization and climate change are favoring the spread of this zoonotic parasite of Asian origin”, highlight the authors of the study, who add that the discovery of the worm occurs both in urban and peri-urban areas (orchard areas).

The Valencia City Council Health Service and the company Laboratorios Lokímica (responsible for pest control) are working with experts from the Faculty of Pharmacy of the University of Valencia, in the framework of a parasitological study of rodents in Valencia. The discovery of the nematode worm, with important repercussions for public health, has occurred both in sewer rats (Rattus norvegicus) and in the black rat (Rattus rattus).

Angiostrongylus cantonensis worm emerging from the pulmonary artery of a rat captured in the orchard area of ​​Valencia. (Photo: Research team / UGR)

The zoonotic transmission of Angiostrongylus cantonensis to humans is through food, through the ingestion of certain foods, specifically both raw or undercooked parasitized snails, as well as contaminated vegetables eaten raw in salads (lettuce, cabbage or radishes). with the slime of the snail with the infective larva.

To date, human cases of eosinophilic meningitis detected in Europe are imported from endemic countries. With this finding, in addition to taking the appropriate prophylactic measures to avoid infection, A. cantonensis must be taken into account in the differential diagnosis in patients with clinical symptoms compatible with parasitic infection, such as severe headache, stiff neck, nausea, vomiting , paresthesia, and/or eosinophilic encephalitis, with or without a history of travel to other endemic countries.

The results of this investigation have already been sent to the Department of Health of the Generalitat Valenciana. In addition, the Valencia City Council and the University of Valencia have established a collaboration agreement on this matter within the framework of the “One Health” (OneHealth) concept, to study rat parasites with the potential for zoonotic transmission and the future possibility of detect resistance to rodenticides used against the two types of rats in which the nematode worm has been found.

The study is titled “Autochthonous Angiostrongylus cantonensis Lungworms in Urban Rats, Valencia, Spain, 2021”. And it has been published in the academic journal Emerging Infectious Diseases. (Source: UGR)