Demographics of the semi-slug Parmarion martensi, an intermediate host for Angiostrongylus cantonensis in Hawai‘i, during laboratory rearing

Abstract

The semi-slug, Parmarion martensi, is an intermediate host of the zoonotic nematode, Angiostrongylus cantonensis, the aetiological agent of neuroangiostrongyliasis or rat lungworm disease in humans. Rearing methods were developed for P. martensi to facilitate studies on nematode transmission and control. Parmarion martensi exhibited high survivorship when reared on a diet of dog food and fresh fruits and vegetables in temperature-controlled cabinets at 21.4°C, 98% relative humidity and 12:12 L:D cycle. Rearing containers were lined with moist paper towels for substrate and plastic pots were provided for hiding/resting and egg-laying. Under these conditions, time to first reproduction was 165.3 ± 12.3 days, fecundity was approximately 34.5 ± 7.8 eggs per adult, and hatch rate was 52.7 ± 3.2%. Survivorship post egg hatch was 86.2 ± 2.9% at 30 days (neonates had a mortality rate of about 14%) and 99% thereafter for up to a year. The demographics of laboratory-reared and wild-caught P. martensi were similar except for the weight of reproductive adults, which was significantly higher in laboratory-reared adults (4.0 ± 0.2 g) than in field-collected adults (1.5 ± 0.1 g).

Phytosanitary irradiation using X‐rays prevents reproduction in the semi‐slug Parmarion martensi (Stylommatophora: Ariophantidae), a host of the human pathogenic nematode Angiostrongylus cantonensis (Rhabditida: Angiostrongylidae)

“…After irradiation treatment, semi‐slugs were returned to the laboratory, transferred to rearing containers in groups of 10 individuals, and held under standard rearing conditions. 26 Individual weights were recorded biweekly and survivorship and reproduction were recorded every 2–3 days until all irradiated semi‐slugs in a cohort had perished or until reproduction in nonirradiated control semi‐slugs had stopped (~217–259 days post treatment). Irradiation treatments at 150 and 400 Gy were replicated 7–11 times each for a total of 70–110 semi‐slugs per treatment depending on availability of semi‐slugs in each age class (Table 1 ).…”

“…2.1 Rearing P. martensi were collected from the wild and reared on a diet of dry dog food and fresh fruits and vegetables in temperaturecontrolled cabinets at 21 °C, 98% relative humidity, and 12 h:12 h light:dark cycle following the methods described by Hamilton et al 26 Under these rearing conditions, time from egg to first reproduction averaged 165 days, adults laid approximately 35 eggs, and egg hatch was about 53%. Survivorship was >90% for up to a year.…”

Angiostrongylus cantonensis and neuroangiostrongyliasis (rat lungworm disease): 2020

“…This Special Issue of Parasitology is based on cutting-edge research presented at the 6th International Workshop on Angiostrongylus and Angiostrongyliasis held in Hilo, Hawai`i, in January 2020. It provides research updates on gastropod and rat infection levels under natural conditions in multiple geographic areas (Niebuhr et al, 2021;Estano et al, 2021;Walden et al, 2021), under laboratory conditions (Hamilton et al, 2021;Wun et al, 2021a, b), as well as alternative parasite transmission pathways (Modry et al, 2021). The latest research on infection in non-human species is described (Feckova et al, 2021;Malik et al, 2021;Tsai and Chen, 2021;Wun et al, 2021a, b).…”

Efficacy of X-Ray Phytosanitary Irradiation on the Infectivity and Reproduction of Angiostrongylus cantonensis in Experimentally Infected Rats

“… 16 We have previously completed a study to determine whether irradiation can inhibit P. martensi reproduction and thereby reduce the risk of the establishment of P. martensi on the U.S. mainland and reduce the potential for transmission of A. cantonensis . 17 , 18 Follett et al. 18 found irradiation at 150 and 400 Gy caused reduced growth, a higher rate of mortality, and prevented reproduction in P. martensi .…”