Dengue is an expanding arboviral disease of variable severity characterized by the emergence of virus strains with greater fitness, epidemic potential and possibly virulence. To investigate the role of dengue virus (DENV) strain variation on epidemic activity we studied DENV-2 viruses from a series of South Pacific islands experiencing outbreaks of varying intensity and clinical severity. Initially appearing in 1971 in Tahiti and Fiji, the virus was responsible for subsequent epidemics in American Samoa, New Caledonia and Niue Island in 1972, reaching Tonga in 1973 where there was near-silent transmission for over a year. Based on whole-genome sequencing and phylogenetic analysis on 20 virus isolates, Tonga viruses were genetically unique, clustering in a single clade. Substitutions in the pre-membrane (prM) and nonstructural genes NS2A and NS4A correlated with the attenuation of the Tongan viruses and suggest that genetic change may play a significant role in dengue epidemic severity.

The safety and efficacy of benzimidazole anthelmintics for the management of rat lungworm disease (neuroangiostrongyliasis) have been questioned regardless of the numerous global experimental animal studies and clinical reports. In this review, 40 of these experimental animal studies and 104 clinical reports are compiled with a focus on albendazole. Among the 144 articles involving an estimated 1034 patients and 2,561 animals, 4.1% were inconclusive or vague regarding the use of benzimidazoles. Of the remaining 138 articles, 90.5% found benzimidazoles to be safe and effective (885 patients; 2,530 animals), 4.3% as safe but ineffective (73 patients; 3 animals), and 5.0% caused adverse reactions (7 patients; 28 animals). Among the clinical reports with a confirmed diagnosis of neuroangiostrongyliasis in which albendazole monotherapy was used, 100% reported high efficacy (743 patients; 479 animals), and in those where albendazole-corticosteroid co-therapy was used, 97.87% were reported to be effective (323 patients; 130 animals).

On Hawai‘i Island, an increase in human neuroangiostrongyliasis cases has been primarily associated with the accidental ingestion of Angiostrongylus cantonensis L3 in snails or slugs, or potentially, from larvae left behind in the slug's slime or feces. We evaluated more than 40 different treatments in vitro for their ability to kill A. cantonensis larvae with the goal of identifying a safe and effective fruit and vegetable wash in order to reduce the risk of exposure. Our evaluation of treatment lethality was carried out in two phases; initially using motility as an indicator of larval survival after treatment, followed by the development and application of a propidium iodide staining assay to document larval mortality. Treatments tested included common household products, consumer vegetable washes and agricultural crop washes. We found minimal larvicidal efficacy among consumer-grade fruit and vegetable washes, nor among botanical extracts such as those from ginger or garlic, nor acid solutions such as vinegar. Alkaline solutions, on the other hand, as well as oxidizers such as bleach and chlorine dioxide, did show larvicidal potential. Surfactants, a frequent ingredient in detergents that lowers surface tension, had variable results, but dodecylbenzene sulfonic acid as a 70% w/w solution in 2-propanol was very effective, both in terms of the speed and the thoroughness with which it killed A. cantonensis L3 nematodes. Thus, our results suggest promising directions for future investigation.

Angiostrongylus cantonensis is a parasitic nematode known to infect humans through the ingestion of third stage larvae which can cause inflammation and damage to the central nervous system. Currently, polymerase chain reaction (PCR) is one of the most reliable diagnostic methods for detecting A. cantonensis in humans as well as in gastropod hosts, but requires expensive and specialized equipment. Here, we compare the sensitivity and accuracy of a recombinase polymerase amplification Exo (RPA-EXO) assay, and a recombinase polymerase amplification lateral flow assay (RPA-LFA) with a traditional quantitative PCR (qPCR) assay currently available. The three assays were used to test 35 slugs from Hawai‘i for the presence of A. cantonensis DNA. Consistent results among the three tests were shown in 23/35 samples (65.7%), while 7/35 (20%) were discordant in low infection level samples (<0.01 larvae per mg tissue), and 5/35 (14.3%) were equivocal. To evaluate sensitivity, a partial ITS1 gene was cloned, and serial plasmid dilutions were created ranging from 100 copies μL−1 to ~1 copy μL−1. All three assays consistently detected 50–100 copies μL−1 in triplicate and qPCR was able to detect ~13 copies μL−1 in triplicate. RPA-EXO was able to detect 25 copies μL−1 in triplicate and RPA-LFA was not able to amplify consistently below 50 copies μL−1. Thus, our RPA-EXO and RPA-LFA assays do not appear as sensitive as the current qPCR assay at low DNA concentrations; however, these tests have numerous advantages that may make them useful alternatives to qPCR.

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