Cryptosporidium

Zahedi, Alireza, Paparini, Andrea, Jian, Fuchun, Robertson, Ian & Ryan, Una, 2016, Public health significance of zoonotic Cryptosporidium species in wildlife: Critical insights into better drinking water management, International Journal for Parasitology: Parasites and Wildlife 5 (1), pp. 88-109 : 100

3.4. Cryptosporidium in amphibians and reptiles

Little is known about Cryptosporidium species infecting amphibians. Of the three orders of amphibians; Anura , Caudata and Gymnophonia, Cryptosporidium has been only reported in Anura which includes frogs and toads and only one species, C. fragile is recognised ( Table 5) (Jirk̊ u et al., 2008). In transmission experiments, C. fragile was not infective in one fish species ( Poecilia reticulate ), four amphibian species ( Bufo bufo , Rana temporaria , Litoria caerulea and Xenopus laevis ), one species of reptile ( Pantherophis guttatus ) and SCID mice (Jirkůet al., 2008). This species has not been reported in humans.

Cryptosporidium infections are ubiquitous in reptiles and have been reported in more than 57 reptilian species (O'Donoghue,1995; Ryan and Xiao, 2014). Unlike in other animals in which Cryptosporidium infection is usually self-limiting in immunocompetent individuals, cryptosporidiosis in reptiles is frequently chronic and sometimes lethal in some snakes. Both intestinal and gastric cryptosporidiosis has been described in snakes and lizards. To date, two species are recognised; C. serpentis (gastric) and C. varanii ( C. saurophilum ) (intestinal) ( Levine, 1980; Pavlasek et al., 1995; Koudela and Modry, 1998; Pavĺasek and Ryan, 2008); neither of which have been reported in humans, but C. serpentis has been identified in cattle ( Azami et al., 2007; Chen and Qiu, 2012). A new intestinal species, Cryptosporidium ducismarci (tortoise genotype II) has been reported in several species of tortoises, snakes and lizards ( Traversa, 2010). Because only molecular data are presented, this species is regarded as a nomen nudum, pending the support of morphological and biological data.

C. parvum , C. muris and Cryptosporidium tyzzeri are also commonly reported in reptiles, particularly snakes but this is thought to be due to mechanical transmission due to predation of infected rodents and is not thought to present a substantial zoonotic risk (Morgan et al., 1999; Xiao et al., 2004b; Pedraza-Diaz et al., 2009; Díaz et al., 2013; da Silva et al., 2014). In addition, various host-adapted genotypes have been identified including tortoise genotype I and snake genotypes I and II (cf. Ryan and Xiao, 2014), which have not been reported in humans ( Table 5) ( Xiao et al., 2004b; Pedraza-Diaz et al., 2009; Traversa, 2010; Seva Ada et al., 2011; Richter et al., 2011; Rinaldi et al., 2012; da Silva et al., 2014; Abe and Matsubara, 2015). There is also a single report of avian genotype V from green iguanas ( Iguana inguana ) ( Kik et al., 2011).