[Effect of the anthelminthic levamisole on the first-stage larva of Angiostrongylus cantonensis in infected rats]

Management of Rat Lungworm Disease (Neuroangiostrongyliasis) Using Anthelmintics: Recent Updates and Recommendations

While there have been legitimate concerns in the past regarding the use of anthelmintics for the management of neuroangiostrongyliasis (rat lungworm disease), recent studies demonstrate that they can be considered safe and efficacious, particularly albendazole, which is regarded as the choice anthelmintic for its management. However, physician hesitancy to prescribe, as well as problems of availability persist, at least in Hawaii, which is considered the epicenter of this disease in the US. As a result, many patients suffer a diminished quality of life or even death. Here, we discuss recent studies that provide insights into new treatments and preventative interventions, which can be more rigorously used for the management of neuroangiostrongyliasis. In summary, results from recent studies suggest that albendazole and avermectins are beneficial for post-exposure management, pyrantel pamoate is beneficial as a post-exposure prophylactic, and levamisole is deserving of further study for the treatment of neuroangiostrongyliasis.

In vitro efficacy of anthelmintics on Angiostrongylus cantonensis L3 larvae

Angiostrongylus cantonensis is the leading cause of eosinophilic meningitis worldwide, with life-threatening complications if not managed correctly. Previous in vitro studies have utilized change in motility patterns of adult female worms to assess the efficacy of anthelmintics qualitatively. However, it is the third stage larvae (L3) that are infectious to humans. With differential staining using propidium iodide penetration as the indicator of death, we can distinguish between dead and live larvae. This assay has enabled us to quantify the in vitro efficacy of nine clinically established anthelmintics on A. cantonensis L3. All drugs were tested at a 1 mm concentration. Piperazine and niclosamide were ineffective in inducing larval death; however, albendazole sulfoxide, pyrantel pamoate, diethylcarbamazine, levamisole and praziquantel were effective as compared to unexposed controls (P < 0.05). Ivermectin and moxidectin did not induce significant levels of mortality, but they considerably reduced larval motility almost immediately. This study indicates the need for further in vivo studies to determine the optimal dose and time frame for post-infection treatment with anthelmintics that demonstrated efficacy.

Effects of anthelmintics on the development of eggs of Angiostrongylus costaricensis in vitro

Effects of the anthelmintics, pyrantel and levamisole, on egg development of Angiostrongylus costaricensis were studied in vitro. After 7 days, about 80% of eggs developed to first-stage larvae in Ham's F-12 medium with 10% foetal calf serum under 5% CO2. Significant inhibition of development was caused by pyrantel (10-9–10-8 g ml-1) and levamisole (10-9–10-8 g ml-1) (Mann-Whitney U-test; P<0.05), and none of the eggs developed to first-stage larvae in higher concentrations of these anthelmintics (10-7 g ml-1). Furthermore, incubation with these drugs at 10-8 g ml-1 for at least 3 h or at 10-4 g ml-1 for 1 h caused irreversible effects on egg development.