The case in RJ is the first transmission in the state in a decade
The Oswaldo Cruz Foundation warns against the transmission of meningitis through snails (eosinophilic meningitis). The concern arose after the death of a patient in April, in the municipality of Nova Iguaçu, in the metropolitan region of Rio de Janeiro. Laboratory tests identified the presence of the worm that causes the disease in a snail in the region where the case was recorded.
Meningitis is a disease characterized by swelling of the meninges, membranes that cover the brain and spinal cord.
The investigation was conducted by the Malacology Laboratory of the Oswaldo Cruz Institute (CIO). Malacology is the branch of biology that studies mollusks. After Fiocruz was informed of the case, agents of the Environmental Health Surveillance (Suvam) of Nova Iguaçu and the CIO collected snails in different points of the Ipiranga neighborhood, where the patient contracted the disease.
Of a total of 22 molluscs analyzed, the worm that causes the disease, Angiostrongylus cantonensis, was found in a snail of the species Pomacea maculata, popularly known as lolô or aruá.
In the state of Rio there have been no cases of snail-borne meningitis since 2014. In Brazil there have been cases since 2006.
Studies by the Fiocruz Schistosomiasis-Malacology Reference Service carried out between 2008 and 2021 have detected the presence of the worm Angiostrongylus cantonensis in 14 units of the federation.
For Silvana Thiengo, director of the Malacology Laboratory of the IOC/Fiocruz, this scenario reinforces the need for attention from health services to diagnose the disease. “Since 2006, we have had cases of eosinophilic meningitis in Brazil. However, many health workers are still unaware of the disease. Doctors must keep this possibility in mind to make the diagnosis and offer adequate treatment,” she said.
Streaming
The worm Angiostrongylus cantonensis, in its life cycle, is a parasite that seeks hosts such as rodents, such as rats, which serve for the development of the adult parasite. The worms reproduce and generate larvae that are eliminated in the feces of the larvae.
The larvae end up ingested by snails. Inside the molluscs they acquire the form capable of infecting vertebrate animals, in other words it is a cycle that repeats itself.
Human infection occurs when people ingest an infected snail or mucus released by it, containing the worm’s larvae. According to Suvam, there are reports that the patient became infected after ingesting a raw freshwater snail.
IOC researchers also collected animals such as rats, guinea pigs and possums in the region where the case occurred to confirm the infection of these mammals. Analysis is ongoing.
Symptoms of the disease
The most common symptom of eosinophilic meningitis is headache. Stiff neck and fever—common in other forms of the disease—are rarer in snail-borne meningitis.
Some patients experience visual disturbances, nausea, vomiting, and persistent paresthesias (tingling or numbness). In most cases, the person recovers spontaneously. Even so, medical monitoring is important because some individuals develop serious conditions, which can lead to death.
Treatment aims to reduce inflammation in the central nervous system and relieve pain, as well as prevent complications.
Treatment
The head of the Malacological Laboratory indicates three main ways to avoid contagion from snails: be careful when handling them, clean vegetables and do not eat these animals raw or undercooked.
In some regions, it is common for snails to be present near homes and places where humans are present. The most common are Achatina fulica, known as the giant African snail.
The recommendation of the health authorities for the disinfestation of these molluscs is to collect them manually, always using gloves or plastic bags to protect your hands. Then put them in a container of boiling water for five minutes. Then break the shells and bury them or throw them in the garbage.
This precaution of breaching protection is to prevent them from becoming breeding grounds for Aedes a Egypti, which transmits diseases such as dengue, Zika and chikungunya.
If exposure to boiling water is not done, the collected shellfish should be placed in a container, such as a bucket or basin, and immersed in a solution made of one part sodium hypochlorite (bleach) to three parts water. After 24 hours of soaking, the solution can be poured off and the shells discarded.
Other important precautions are: do not eat raw or undercooked shellfish, including land snails, slugs and aquatic snails; and wash fruits and vegetables well, leaving them to soak for 30 minutes in a mixture of a liter of water and a tablespoon of bleach, rinsing well under running water before consuming.
In addition to providing guidance to the population, Fiocruz reinforces the importance of municipal surveillance agents who map the risks of infection, through the periodic collection of shellfish and sending them for parasitological analysis carried out by the CIO/Fiocruz Reference Service.
“Few municipalities regularly send samples for parasitological analysis. Vector surveillance services often have to focus their teams on fighting epidemic diseases, such as dengue, and snail surveillance is left unattended,” says Reference Laboratory coordinator Elizangela Feitosa.
Nova Iguaçu is one of the cities where monitoring is carried out regularly. “Usually the population appeals because of the nuisance caused by the African snail. But, knowing that we have an emerging disease, we have collected samples for parasitological surveillance and we have shown residents how to collect snails safely, to try to reduce or eliminate this vector,” explains the municipality’s malacological surveillance manager, José de Arimatea Brandão. Lorenzo.
In a note, the Health Directorate of the State of Rio de Janeiro reported that it has not yet been informed by the Municipal Health Directorate of Nova Iguaçu and that it has mobilized, this Monday (1), a technical team to investigate the case.
Editing: Juliana Andrade
Source: Terra
Ben Stock is a lifestyle journalist and author at Gossipify. He writes about topics such as health, wellness, travel, food and home decor. He provides practical advice and inspiration to improve well-being, keeps readers up to date with latest lifestyle news and trends, known for his engaging writing style, in-depth analysis and unique perspectives.
