Diversity and Seasonal Impact ofAcanthamoebaSpecies in a Subtropical Rivershed

Abstract

This study evaluated the presence of Acanthamoeba species in the Puzih River watershed, which features typical subtropical monsoon climate and is located just above the Tropic of Cancer in Taiwan. The relationship between the seasonal and geographical distributions of Acanthamoeba species in this rivershed was also investigated. Acanthamoeba species were detected in water samples using the amoebal enrichment culture method and confirmed by PCR. A total of 136 water samples were included in this study, 16 (11.7%) of which contained Acanthamoeba species. Samples with the highest percentage of Acanthamoeba (32.4%) were obtained during the summer season, mainly from upstream areas. The identified species in the four seasons included Acanthamoeba palestinensis (T2), Acanthamoeba sp. IS2/T4 (T4), Acanthamoeba lenticulata (T5), Acanthamoeba hatchetti (T11), Acanthamoeba healyi (T12), and Acanthamoeba jacobsi (T15). The most frequently identified Acanthamoeba genotype was T4 (68.7%). Acanthamoeba genotype T4 is responsible for Acanthamoeba keratitis and should be considered for associated human health risk potential in the rivershed.

Detection rates of waterborne protozoa in water sources from Fayoum Governorate

“…The lower detection rates of amoeboflagellates in comparison to Acanthamoeba spp. in the present study may be due to their domestic distribution instead of different habitat conditions (air, water, soil) for the latter [37,41] . Low detection rates were recorded in Nicaragua (9%, 4% and 5%), respectively [27] .…”

“…Our high detection rate was attributed to the time of study as the samples were collected from May to October, 2015, and most of Acanthamoeba spp. prevail during summer months [37] . Another explanation for the high detection rate of Acanthamoeba spp.…”

The relationship between environmental sources and the susceptibility of Acanthamoeba keratitis in the United Kingdom

“…The latter study also found that the incidence of AK was much greater in areas supplied with hard water, which enhances limescale formation on pipes and so increases colonisation of Acanthamoeba [18]. Furthermore, distance from water purification plants, use of stagnant water (for example cisterns), and warmer air temperature were found can be associated with higher incidence of AK [14,[19][20][21][22][23][24][25][26]. In a more recent outbreak that started in the UK in 2010-2011 a three-fold increase in the incidence of AK was reported compared to the outbreak in 2004-2009 [27].…”

Occurrence of Acanthamoeba species in the Damanhour Drinking Water Treatment Plant, Behera Governorate (Egypt)

“…were isolated from 26.9% of tap water samples by Kilvington et al 34 The difference in detection rates of free-living amoebae in different countries and localities may be influenced by geographical conditions and raw water sources. [35][36][37] The results of the present study showed that the percentage of Acanthamoeba-positive samples in the inlet water of the DWTP were the same in all seasons of the year (33.3%). However, in the outlet drinking water, the percentage of positive samples reached 33.3% in spring and summer, while they were 0% in both winter and autumn.…”

“…Several workers in different countries reported seasonal variations in the distribution of Acanthamoeba in freshwater samples, with the highest percentage either in autumn [38][39][40] or in summer. 37,41,42 During the present study, a simple PCR technique was applied, using genus-specific primers, to confirm the results obtained by morphological identification of the isolated Acanthamoeba, but PCR confirmation at the species level is still needed. PCR has been found to be a more sensitive diagnostic test than culture.…”