Identification of Uncommon Cryptosporidiumviatorum (a Novel Subtype XVcA2G1c) and Cryptosporidium andersoni as Well as Common Giardia duodenalis Assemblages A and B in Humans in Myanmar

Abstract

<i>Cryptosporidium</i> and <i>Giardia</i> are two important zoonotic intestinal protozoa responsible for diarrheal diseases in humans and animals worldwide. Feces from infected hosts, water and food contaminated by <i>Cryptosporidium</i> oocysts and <i>Giardia</i> cysts as well as predictors such as poverty have been involved in their transmission. Myanmar is one of the world's most impoverished countries. To date, there are few epidemiological studies of <i>Cryptosporidium</i> and <i>Giardia</i> in humans. To understand the prevalence and genetic characterization of <i>Cryptosporidium</i> spp. and <i>Giardia duodenalis</i> in humans in Myanmar, a molecular epidemiological investigation of the two protozoa was conducted in four villages of Shan State. 172 fecal specimens were collected from Wa people (one each) and identified for the presence of <i>Cryptosporidium</i> spp. and <i>G. duodenalis</i> by sequence analysis of their respective small subunit ribosomal RNA genes. 1.74% of investigated people were infected with <i>Cryptosporidium</i> spp.-<i>C. andersoni</i> (n = 2) and <i>C. viatorum</i> (n = 1) while 11.05% infected with <i>G. duodenalis</i>-assemblages A (n = 6) and B (n = 13). By sequence analysis of 60-kDa glycoprotein gene, the <i>C. viatorum</i> isolate belonged to a novel subtype XVcA2G1c. DNA preparations positive for <i>G. duodenalis</i> were further subtyped. Five of them were amplified and sequenced successfully: different assemblage B sequences (n = 2) at the triosephosphate isomerase (tpi) locus; sub-assemblage AII sequence (n = 1) and identical assemblage B sequences (n = 2) at the β-giardin (bg) locus. This is the first molecular epidemiological study of <i>Cryptosporidium</i> spp. and <i>G. duodenalis</i> in humans in Myanmar at both genotype and subtype levels. Due to unclear transmission patterns and dynamics of <i>Cryptosporidium</i> spp. and <i>G. duodenalis</i>, future research effort should focus on molecular epidemiological investigations of the two parasites in humans and animals living in close contact in the investigated areas, even in whole Myanmar. These data will aid in making efficient control strategies to intervene with and prevent occurrence of both diseases.