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Published Date: 2007-04-14 14:00:02
Subject: PRO/AH/EDR> Angiostrongylus meningitis - Brazil (ES)
Archive Number: 20070414.1244

ANGIOSTRONGYLUS MENINGITIS - BRAZIL (ESPIRITO SANTO)
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International Society for Infectious Diseases
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Date: Sat 14 Apr 2007
From: ProMED-mail <promed@promedmail.org, from ProMED-PORT
<promed-port@promedmail.org>
Source: Ministry of Health Brazil [Trans. from Portuguese by Mod.MPP, edited]
<http://portal.saude.gov.br/portal/saude/visualizar_texto.cfm?idtxt=25832>

In the 2nd half of March 2007, the Secretary of Disease Surveillance
of the Ministry of Health received a report from the State
Secretariat of Health of Espirito Santo (ES) of 2 cases of
eosinophilic meningitis in the city of Cariacica, ES.
Eosinophilic meningitis is an infection of the central nervous system
caused mainly by helminths, but other infectious and non-infectious
processes can be associated with this clinical picture. Among the
helminths, of special importance is the _Angiostrongylus
cantonenesis_, a nematode that has the rat (urban and wild) as its
definitive host. The intermediary hosts in nature are mollusks, among
which are conch (caramujos) and slugs (lesmas). Humans are accidental
hosts, being infected through ingestion of mollusks or coming in
direct contact with their secretions.
In the identified cases, the probable source of infection was
ingestion of slugs. A 3rd case, under investigation, still hasn't had
a definitive epidemiologic association identified, not withstanding,
the literature does support the possibility of transmission of the
helminth through ingestion of vegetables and fruits that have been
infested with infectious larval forms of _A. cantonensis_ or through
the ingestion of other hosts of the helminth such as crabs and
shrimp. These forms of transmission have been reported in eastern
(Asian) countries where the disease is endemic. The occurrence of
this agent has not been reported in Brazil, suggesting a new
introduction of this species into the Brazilian territory.
The confirmation of the etiologic agent in both of the cases was made
by polymerase chain reaction (PCR) testing of cerebrospinal fluid
(CSF) from both patients, as well as through verification of
reproduction of the agent in laboratory rats, in addition to the
identification of _A. cantonensis_ in slugs and conches and other
mollusks collected around the household where the ingestion of the
cited animals occurred.
Pathophysiology
----------------
The infection occurs through the ingestion of infective larvae (L1)
present in the mollusks, by contact of the oral mucosa with
secretions of mollusks or maybe though fomites (contaminated
objects). The larvae, after having been ingested, enters the blood
system, and, as a result of its tropism, is localized in the central
nervous system (CNS) where it goes on to develop meningitis or infect
cerebral tissue and cause encephalitis. In this way, through the
infectious process involving these different sites, the clinical
picture of meningoencephalitis is produced. It is not known if the
adult worm, due to an inability to migrate to the lungs, dies inside
of the CNS or in another location.
Clinical picture
-----------------
Incubation period -- from one to 6 days after ingestion of the L1.
Signs and Symptoms -- headache, nausea, nuchal rigidity, fever, rash,
abdominal pain
Specific neurological signs -- can be absent or can evolve into
paresthesias, hypotonia, and compromise of the 4th and 6th cranial
nerves. It can lead to death, although this is rarely reported.
Laboratory tests
----------------
It is mandatory to collect CSF. The CSF normally has a leukocytosis
with eosinophilia reaching 10 percent that can persist for months.
Glucose can be normal and for some time can be decreased. Sometimes
the larvae can be identified in the CSF at the time of the lumbar puncture.
There is usually an eosinophilia in the peripheral blood, concomitant
with the neurological picture. Serologic tests have not as yet been
standardized commercially.
Therapy
--------
The use of an anti-helminthic has not been demonstrated to be
effective at any time during the course of the disease.
Treatment of signs and symptoms during the course of the illness is
recommended to reduce the symptoms (headache and other signs of
increased intracranial pressure), as well as the use of analgesics
and antiemetics.
The usual clinical course evolves over 2 months but in some cases can
last longer.
Definition of a suspected case: a patient of any age and sex, with a
history of fever, headache nuchal rigidity, with a history of
ingestion or manipulation of landed mollusks in the preceding 1-15 days.
Definition of a confirmed case: a suspected case with a CSF
eosinophilia of 10 percent or a CSF positive for _A. cantonensis_.
Prevention and control measures to be implemented in Espirito Santo State:
a) All suspected cases of eosinophilic meningitis should be reported
immediately to the Municipal and/or State Secretariat of Health (to
the Rapid Response Unit -- URR) and/or to the Center for Strategic
Information for Disease Surveillance of the Ministry health
(CIEVS/SVS) through e-mail <notifica@saude.gov.br>;
b) Seek immediate medical assistance at the primary signs and
symptoms of fever, accompanied by vomiting and nuchal rigidity;
c) remove unnecessary materials by emptying the garbage adequately in
order to reduce the rodent populations;
d) avoid manual contact or ingestion of whatever species of landed
mollusks, until there are studies of these fauna in the region and
one is able to identify the transmission risks;
e) ingest fruits and vegetables only after adequate washing and use
of sodium hypochlorite 2.5 percent disinfectant;
f) mollusks and terrestrial and/or aquatic crustaceans should only be
ingested after adequate cooking;
g) special attention should be paid to children, teaching them the
risks and keeping them in clean environments less hospitable to the
mollusks (care should be taken with yards, pre-schools and daycare centers;
The Municipal and State Secretaries of Health should:
1. Sensitize the health professionals and the teams that provide
assistance to meningitis [patients] in the private and public
hospitals about the risk of occurrence of the disease caused by _A.
cantonensis_;
2. implement a system that ensures collection of CSF from all cases
with signs and symptoms described above, that are compatible with a
suspect case;
3. the chemocytologic examination of the CSF should include analysis
of the cellular differential as well as a biochemical analysis;
4. there should be collection of the CSF to be sent to LACEN (Center
for the Study and Control of Infectious Diseases), which will send
the specimen for PCR testing for the presence of _A. cantonensis_.
The specimens should be maintained and transported on dry ice or
stored in a liquid nitrogen pipe.
5. all suspected cases should be investigated by Epidemiologic
Surveillance (VE), Environmental Health and VISAS (Sanitary
Monitoring), with special attention to:
- dietary habits (ingestion of raw mollusks or poorly cooked mollusks
and/or crustaceans; types of naturally ingested foods such as fruits,
vegetables and origin of these foods, for both the occurrence of
manipulation of the terrestrial and marine mollusks in the preceding 7 days;
- completion of an environmental investigation around the household
and peri-domicile of the suspected cases, with collection of
terrestrial mollusks encountered in the locale (in keeping with the
orientation of CCZ (Center for Zoonoses Control), to identify the
mollusks (conches and slugs) and implement rodent control in keeping
with the environmental characteristics.
For the rest of the State and Municipal Secretariats of Health:
Implementation of prospective epidemiologic surveillance for
eosinophilic meningitis, doing a retrospective review of the past 6
months, looking for compatible clinical pictures and the presence of
CSF eosinophilia. If cases that fit the clinical picture for a
suspected case are identified, the CIE, VS should be notified within
24 hours and all measures of investigation should be conducted as
mentioned above.
[Byline: Jose Ricardo Pio Marins, Gerson Pena]
--
ProMED-mail
<promed@promedmail.org>
[This is not necessarily due to _A. cantonensis_, as there are other
causes. Despite this, the presence of _Achatina fulica_ in Brazil,
the intermediary host of _A. cantonensis_ is of concern. - Mod. LJS]
[More information on the lifecycle and diagnosis of _Angiostrongylis_
can be found at the CDC website
<http://www.cdc.gov/ncidod/dpd/parasites/angiostrongylus/default.htm>.
It should be noted that, in addition to an elevated eosinophil count
in both spinal fluid and peripheral blood, the total IgE level in
blood would be expected to be highly elevated. - Mod.EP]

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