Parasitological and molecular study of the furcocercariae from Melanoides tuberculata as a probable agent of cercarial dermatitis

Abstract

Cercarial dermatitis is caused by animal schistosomes in many parts of the world including Iran. Various stages of the parasites have been studied in intermediate and definitive hosts in northern and southwestern Iran; however, no molecular investigation for species identification and classification of these agents has been carried out, so far. In the present study, more than 3,800 aquatic snails were collected from water sources of Khuzestan, southwest Iran. The snails were identified as Lymnaea gedrosiana, Radix auricularia, Melanoides tuberculata, Melanopsis sp. and Physa acuta. They were examined for schistosome cercariae. Two specimens of M. tuberculata were infected with ocellate furcocercariae belonging to the family Schistosomatidae. Molecular studies were carried on these schistosomatid samples. Both samples belong to an unknown schistosome species and genus in sister position to Gigantobilharzia-Dendritobilharzia clade. They differ from other species in their ITS sequence region as well as in their intermediate host specificity--This is one of the first reports on schistosome cercariae from M. tuberculata and the first including molecular data. Due to adaptability and invasiveness of this snail species, this new schistosome species, as a potential causative agent of cercarial dermatitis in humans, needs to be studied further.

Avian Schistosomes and Outbreaks of Cercarial Dermatitis

“…At the base of clade D is an unresolved group of avian schistosomes, most of which have been implicated in dermatitis outbreaks and comprise the most diverse range of both bird and snail (9 families) host use (13,40,(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66). Current results based on all of the available sequence data in GenBank for the internal transcribed spacer (ITS) region indicate that there are about nine distinct lineages, only two of which are described: Gigantobilharzia and Dendritobilharzia (40,(64)(65)(66)(67)(68)(69).…”

“…Current results based on all of the available sequence data in GenBank for the internal transcribed spacer (ITS) region indicate that there are about nine distinct lineages, only two of which are described: Gigantobilharzia and Dendritobilharzia (40,(64)(65)(66)(67)(68)(69). Most of the lineages in this part of clade D have one to a few species and have been seen in only a few cases, many related to dermatitis outbreaks (12) ( Table 1).…”

“…For example, in the San Francisco Bay area (California), one beach in particular has annual cases of dermatitis (64). The prevalence of dermatitis caused by schistosomes from Valvata or Melanoides snails (63,65,66) depends on how often people use areas where these snails release cercariae.…”

“…These outbreaks have been reviewed extensively (7,8,70,71). Species of Trichobilharzia have been reported to cause dermatitis from other areas as well, such as Rwanda-Burundi (72), South Africa (73,74), New Zealand and Australia (75)(76)(77)(78)(79), Malaysia/Indonesia (80)(81)(82), Iran (65,(83)(84)(85)(86), United Arab Emirates (66), Thailand (87), and China (88,89) in the Eastern Hemisphere and Argentina (57,90,91), Chile (11), and El Salvador (92) in the Western Hemisphere. We are just beginning to better understand the significant disease components for dermatitis as a global problem.…”

Biosorption of Cadmium from Aqueous Solution by Shell Dust of the Fresh Water SnailMelanoides tuberculata

“…To substantiate this proposition, an attempt was made to assess metal biosorption capacity of the shell dust of Melanoides tuberculata (Muller 1774) (Gastropoda: Thiaridae) using cadmium as a model metal. Although native to North Africa and South Asian regions, M. tuberculata is available globally as an invasive species in freshwater ecosystems (Duggan 2002;Appleton 2003;Facon et al 2003;Karamian 2011) and are associated with the spread and transmission of different helminth diseases (Ben-Ami and Heller 2003;Brinesh and Janardan 2011;Boerlage et al 2013). In different geographical regions, fishes (Chimbari and Madsen 2013;Hung et al 2013) and other control methods against Melanoides tuberculata generate dead shells rich in calcium carbonate.…”