Evaluating host–parasite co-adaptation relationships involving Angiostrongylus costaricensis

Abstract

Angiostrongylus costaricensis is a parasite that infects rodents, including the wild cotton rat Sigmodon hispidus and pygmy rice rats Oligoryzomys spp., among others. However, urban Rattus norvegicus and Mus musculus have not been identified as important hosts of A. costaricensis. In this study, Swiss mice (SW), Wistar R. norvegicus (RN), wild Oligoryzomys nigripes (ON) and a local strain of M. musculus (RGS) were experimentally infected with A. costaricensis. Survival, elimination of L1 (total sum per group, A0), and the number of adult worms recovered divided by the dose of each L3 inoculum (yield ratio, YR) were examined for each group after a 40-day post-infection period. The survival rates, A0 and YR values were: 27%, 207,589 and 0.42 for the SW group; 81%, 8691 and 0.01 for the RN group; and 63.6%, 26,560 and 0.16 for the RGS group, respectively, in each case. The survival rate for the ON group was 100% and the A0 value was 847,050. A YR was not calculated for the ON group since the ON group was maintained up to 565 days post-infection (pi) to examine long-term mortality. At 500 days pi (16 months), 50% of the ON group had died, while one animal (10%) survived 595 days pi (20 months). Taken together, these data indicate that A. costaricensis has undergone a greater degree of adaptation to the wild rodent, O. nigripes, than to R. norvegicus or a local M. musculus strain. In addition, titre curve (A0) modelling of adaptation status proved to be useful in evaluating A. costaricensis-rodent interactions.

Abdominal angiostrongyliasis: pathologic findings in Swiss mice infected with different doses of Angiostrongylus costaricensis

“…Similar findings were previously reported by Hermes et al (2018), who showed that survival was longer among mice infected with five L3 of A. costaricensis than among those infected with higher doses, as was the time to eliminate L1 in faeces. These findings indicate that it is possible to inoculate mice with lower doses in order to maintain the life cycle of the parasite in animal facilities, despite the high mortality rates reported (Garrido et al ., 2017).…”

“…Mice infected with 15 L3 have been shown to die sooner than do those infected with 30 L3 (Hermes et al , 2018). The genetic variability of each mouse and its resistance to infection are also factors that affect survival (Ishih & Sano, 1989; Garrido et al , 2017). Our histopathological findings contribute to elucidating these temporal differences.…”

Abdominal angiostrongyliasis can be diagnosed with a immunochromatographic rapid test with recombinant galactin from Angiostrongylus cantonensis

“…Parasitological diagnosis is not an option in angiostrongyliasis, since larvae in feces was never consistently detected in AA patients and only rarely documented in cerebrospinal fluid in eosinophilic meningitis. 6 Development of immunological methods have faced two main difficulties: (i) large production of antigens is laborious and it depends on in vivo maintenance of parasites, especially for A. costaricensis , which shows less than optimal adaptability to laboratory mice strains; 7 (ii) lack of a large reference panel of sera with precise characterisation of true-positive samples by histopathology. Complicated abdominal angiostrongyliasis leading to biopsy or anatomopathological examination and identification of the parasite is not frequent.…”