Classification ofCryptosporidiumSpecies from Patients with Sporadic Cryptosporidiosis by Use of Sequence-Based Multilocus Analysis following Mutation Scanning

Abstract

In the present study, we analyzed genetic variation in Cryptosporidium species from humans (n ‫؍‬ 62) with clinical cryptosporidiosis in South Australia. Sequence variation was assessed in regions within the small subunit of nuclear rRNA (p-SSU), the 70-kDa heat shock protein (p-hsp70), and the 60-kDa glycoprotein (p-gp60) genes by employing single-strand conformation polymorphism analysis and sequencing. Based on the analyses of p-SSU and p-hsp70, Cryptosporidium hominis (n ‫؍‬ 38) and Cryptosporidium parvum (n ‫؍‬ 24) were identified. The analysis of p-gp60 revealed eight distinct subgenotypes, classified as C. hominis IaA17R1 (n ‫؍‬ 3), IbA9G3R2 (n ‫؍‬ 14), IbA10G2R2 (n ‫؍‬ 20), and IfA12G1R1 (n ‫؍‬ 1), as well as C. parvum IIaA18G3R1 (n ‫؍‬ 15), IIaA20G3R1 (n ‫؍‬ 6), IIaA22G4R1 (n ‫؍‬ 2), and IIcA5G3R2 (n ‫؍‬ 1). Subgenotypes IaA17R1 and IIaA22G4R1 are new. Of the six other subgenotypes, IbA10G2R2, IIaA18G3R1, IIaA20G3R1, and IIcA5G3R2 were reported previously from the state of Victoria. This is the fourth record in Australia of C. parvum subgenotype IIaA18G3R1 from humans, which, to date, has been isolated only from cattle in other countries. This subgenotype might be a significant contributor to sporadic human cryptosporidiosis and may indicate a greater zoonotic contribution to the infection of humans in the area of study. Comparative analyses revealed, for the first time, the differences in the genetic makeup of Cryptosporidium populations between two relatively close, major metropolitan cities.

Molecular Epidemiology, Spatiotemporal Analysis, and Ecology of Sporadic Human Cryptosporidiosis in Australia

“…This observation is consistent with previous Australian studies investigating sporadic human cryptosporidiosis (4,9,14). No gender bias or regional segregation between the distributions of C. hominis and C. parvum infec- on May 10, 2018 by guest http://aem.asm.org/ tions was detected.…”

“…This subtype is the most common cause of sporadic cryptosporidiosis around the world, with 44.5% of total reported infections attributed to it (8). Subtype IbA10G2 was also previously identified as the most common cause of sporadic disease in Australia and was the cause of the 2009 New South Wales waterborne outbreak (9,14,22,23). The second most frequently detected Cryptosporidium subtype from humans was C. parvum IIaA18G3R1, which was identified in 15% of isolates.…”

“…The second most frequently detected Cryptosporidium subtype from humans was C. parvum IIaA18G3R1, which was identified in 15% of isolates. The occurrence of this subtype in humans was first reported in Australia, and it has previously been identified as the most common C. parvum subtype causing sporadic cryptosporidiosis in New South Wales (4,9,10,14,22). Subtype IIaA18G3R1 is also the dominant type of C. parvum causing illness in humans in Ireland (26).…”

“…In Australia, C. parvum IIaA18G3R1 is the dominant subtype infecting cattle. The identification of IIaA18G3R1 in humans was first reported in Australia, and it has now become the dominant C. parvum subtype causing Australian sporadic cryptosporidiosis (9,14,22). Cattle zoonotic sources have also been shown in Portugal, where C. parvum IIaA15G2R1 is the most common subtype in cattle and humans (1).…”

Molecular Epidemiology and Spatial Distribution of a Waterborne Cryptosporidiosis Outbreak in Australia

“…This subtype has a global distribution, and 44.5% of global human Cryptosporidium infections that have been studied to the subtype level have been attributed to it (13,14,20,27). The C. hominis IbA10G2 subtype is also the most common cause of sporadic human infections in Australia (13,14,20,27) and has been the agent responsible for large waterborne cryptosporidiosis outbreaks in the United States, Northern Ireland, and France (7,11,31 Cryptosporidium hominis is a specialist pathogen, specifically adapted to the human host. Conversely, C. parvum is a generalist, capable of causing infections in humans and a variety of ruminant species.…”