Rat lungworm (Angiostrongylus cantonensis) is a neurotropic nematode, and the leading cause of eosinophilic
meningitis worldwide. The parasite is usually contracted through ingestion of infected gastropods, often hidden in raw or partially cooked produce.
Pharmaceutical grade
pyrantel pamoate was evaluated as a post-exposure prophylactic against A. cantonensis.
Pyrantel pamoate is readily available over-the-counter in most pharmacies in the USA and possesses
anthelmintic activity exclusive to the gastrointestinal tract (GIT). Administering
pyrantel pamoate immediately after exposure should theoretically paralyze the larvae in the GIT, causing the larvae to be expelled via peristalsis without entering the systemic circulation. In this study,
pyrantel pamoate (11 mg/kg) was orally administered to experimentally infected rats at 0, 2-, 4-, 6-, or 8-h post-
infection. The rats were euthanized six weeks post-
infection, and worm burden was evaluated from the heart-lung complex. This is the first in vivo study to evaluate its efficacy against A. cantonensis. This study demonstrates that
pyrantel pamoate can significantly reduce worm burden by 53-72% (P = 0.004), and thus likely reduce the severity of
infection that is known to be associated with worm burden. This paralyzing effect of
pyrantel pamoate on the parasite may also be beneficial for delaying the establishment of
infection until a more suitable
anthelmintic such as
albendazole is made available to the patient.