Recently, emerging waterborne protozoa, such as microsporidia, Cyclospora, and Cryptosporidium, have become a challenge to human health worldwide. Rapid, simple, and economical detection methods for these major waterborne protozoa in environmental and clinical samples are necessary to control infection and improve public health. In the present study, we developed a multiplex PCR test that is able to detect all these 3 major waterborne protozoa at the same time. Detection limits of the multiplex PCR method ranged from 101 to 102 oocysts or spores. The primers for microsporidia or Cryptosporidium used in this study can detect both Enterocytozoon bieneusi and Encephalitozoon intestinalis, or both Cryptosporidium hominis and Cryptosporidium parvum, respectively. Restriction enzyme digestion of PCR products with BsaBI or BsiEI makes it possible to distinguish the 2 species of microsporidia or Cryptosporidium, respectively. This simple, rapid, and cost-effective multiplex PCR method will be useful for detecting outbreaks or sporadic cases of waterborne protozoa infections.
Cryptosporidium/*isolation & purification ; Cyclospora/*isolation & purification ; DNA Primers/genetics ; DNA Restriction Enzymes/metabolism ; DNA, Protozoan/genetics/metabolism ; Humans ; Microsporidia/*isolation & purification ; Parasitology/*methods ; Polymerase Chain Reaction/*methods ; Polymorphism, Restriction Fragment Length ; Sensitivity and Specificity ; Water/*parasitology

Cyclospora cayetanensis is a foodborne and waterborne pathogen that causes endemic and epidemic human diarrhea worldwide. A few epidemiological studies regarding C. cayetanensis infections in China have been conducted. During 2013, a total of 291 stool specimens were collected from patients with diarrhea at a hospital in urban Shanghai. C. cayetanensis was not detected in any of the stool specimens by traditional microscopy, whereas five stool specimens (1.72%, 5/291) were positive by PCR. These positive cases confirmed by molecular technology were all in the adult group (mean age 27.8 years; 2.94%, 5/170) with watery diarrhea. Marked infection occurred in the rainy season of May and July. Sequence and phylogenetic analyses of the partial 18S rRNA genes of C. cayetanensis isolated showed intra-species diversity of this parasite. This study showed, for the first time, that C. cayetanensis is a pathogen in outpatients with diarrhea in Shanghai, albeit at a low level. However, the transmission dynamics of this parasite in these patients remain uncertain.
Adolescent ; Adult ; China ; epidemiology ; Cyclospora ; genetics ; isolation & purification ; Cyclosporiasis ; epidemiology ; Diarrhea ; etiology ; parasitology ; Feces ; parasitology ; Female ; Humans ; Male ; Middle Aged ; Outpatients ; Phylogeny ; Polymerase Chain Reaction ; RNA, Ribosomal, 18S ; analysis ; Retrospective Studies ; Young Adult