Angiostrongylus cantonensis is a zoonotic, parasitic nematode causing angiostrongyliasis or rat lungworm disease. Clinical diagnosis in humans is currently confirmed by detection of parasite DNA in cerebrospinal fluid. This study estimated human exposure to A. cantonensis in volunteer participants solicitated via public venues on east Hawai'i Island using blood-based tests. Antibodies were screened in sera by crude antigen ELISA, followed by a 31-kDa dot-blot test developed and validated in Thailand. Human participants (n = 435) donated blood samples and completed a questionnaire to self-report relevant symptomology or clinical diagnosis. Among symptoms reported by participants diagnosed by licensed clinicians, headaches, high eosinophil counts, stiff neck, fatigue, and joint pain were most severe during the initial 3 months of infection. ELISA results revealed 22% of the serum samples as positive, 46% as equivocal, and 32% as negative. A subset of 186 samples was tested by dot blot, with 30% testing positive and 70% testing negative. A significantly higher mean ELISA value was found among recently (2014)(2015) clinically diagnosed participants as than among those with a diagnosis before 2010 (P = 0.027). All dot-blot positives were also ELISA positive and were significantly associated with higher ELISA values compared with dot-blot negatives (P = 0.0001). These results suggest that an ELISA using crude antigen isolated from adult A. cantonensis from Hawai'i may be an effective initial screening method for estimating exposure to A. cantonensis in Hawai'i and likewise suggest that dot-blot tests using the 31-kDa antigen exhibit efficacy as a diagnostic for exposure.

Summary157 sera from pregnant women have been examined and 2 precipitating antibodies with Ag specificity have been detected, one in the serum of a puerpera after the 7th delivery and one in the serum of a woman after the 6th delivery. Neither of the women had ever received a blood transfusion.Résumé157 sérums provenant de femmes enceintes ont été examinés et on a découvert parmi ces 157 sérums, 2 sérums contenant des anticorps précipitants, avec la spécificité Lp; 1 des sérums provenait d'une femme en couche, après la septième grossesse et l'autre de ces sérums provenait d'une femme après la sixième grossesse. Aucune de ces femmes n'avait reçu auparavant de transfusion de sang.ZusammenfassungUnter 157 Seren von Multiparae wurden zwei gefunden, die präzipitierende Anti‐Ag‐Antikörper enthielten. In einem Fall handelte es sich um eine Wöchnerin nach der 7. Geburt; im anderen Fall um eine solche nach der 6. Geburt. Keine der beiden Frauen hatte je Bluttransfusionen erhalten.

The nematode Angiostrongylus cantonensis is a rat lungworm, a zoonotic pathogen that is the cause of human eosinophilic meningitis and ocular angiostrongyliasis. It is considered as a global, emerging infectious disease commonly known as rat lungworm disease (RLWD). Rats are the definitive hosts, mollusks are the obligatory intermediate hosts. Humans can become infected by ingesting intermediate hosts containing infective larvae in contaminated food or water. There are currently no diagnostic tests for RLWD available in Hawaii and prevalence of infection is unknown. To estimate prevalence of exposure to RLW parasites, working with Clinical Labs of Hawaii, LLP and Puna Community Medical Center in Pahoa, HI, we collected serum from 436 human volunteers from east Hawaii where most of the cases of RLWD in the USA originate. The presence of RLW antibodies were evaluated by indirect ELISA using crude antigen extracted from adult A. cantonensis nematodes. Of the 360 samples successfully analyzed, 76 (21%) were strongly positive, 166 (46%) weakly positive and 118 (33%) negative. Based on self-reported data, 92 (26%) believed they have or had RLWD, and 15 (4.2%) were definitively diagnosed. 77% of volunteers reported catchment systems as their main source of household water. More studies would need to be completed to evaluate the potential for water transmission of RLWD. Due to the potential for false positives using crude RLW antigen, results will be verified using dot-blots containing a 31 kDa protein which is expected to provide greater specificity.