New insights into the detection and molecular characterization of Cryptosporidium with emphasis in Brazilian studies: a review

Abstract

Cryptosporidium spp. is a pathogenic protozoan present in the gastrointestinal tract of several hosts. This protozoan was originally classified as within the Coccidia Class and has recently been reclassified to gregarine based on studies that observed the evolutionary phases from the process of excision and sequencing of the 18S rRNA gene. Molecular biology techniques have become diagnostic tools and have also been used to understand the epidemiology of Cryptosporidium spp., since several species of this genus are very similar morphologically and morphometrically. Molecular techniques have been used in the identification of parasites, at the species and subtypes levels and to study disease transmission. The laboratory diagnosis of human cryptosporidiosis can be made by parasite detection methods, such as optical microscopy, antigens or genetic material detection, as well as serum antibodies raised to Cryptosporidium spp. Molecular methods were developed and allowed, not only an extensive revision of the taxonomy, but also an improvement in the laboratory diagnosis. In Brazil, there are few reports of Cryptosporidium spp. outbreaks in humans and all of them took place in nurseries. A few epidemiological studies developed in Brazil have used molecular methods for the detection of Cryptosporidium spp., as well as genotyping studies of their species and subtypes. The use of real-time PCR, together with microscopy and immunochromatography techniques, would result in a more precise diagnosis of cryptosporidiosis. The analysis of genotypes, subtypes and clonality of Cryptosporidium could be useful to understand and define the prognosis and severity of infections.

Prevalence and Genetic Characterization of Cryptosporidium, Giardia and Enterocytozoon in Chickens From Ezhou, Hubei, China

“…To date, 38 species of Cryptosporidium have been identified in diverse hosts, totaling more than 40 subtypes infecting mammals (22)(23)(24). Among these, C. hominis and C. parvum are the main pathogens infecting humans and responsible for approximately 90% of human cryptosporidiosis (25).…”

Cryptosporidiosis and Giardiasis in Buffaloes (Bubalus bubalis)

“…To date, at least 38 species of Cryptosporidium spp. have been recognized by molecular characterization ( 39 – 41 ), with 73 genotypes ( 42 – 44 ) and 17 species having been identified in humans ( 45 ).…”

Performance of a rapid diagnostic test for the detection of Cryptosporidium spp. in African children admitted to hospital with diarrhea

“…They include the use of faecal smears stained by the modified Ziehl-Neelsen technique, Enzyme-linked immunosorbent assays (ELISA) and polymerase chain reaction (PCR) assays [13][14]. A comprehensive overview into the detection and molecular characterization of Cryptosporidium has been described elsewhere [15] The above mentioned methods have drawbacks such as being time-consuming and relatively expensive, as well as requiring well-equipped laboratories and well-trained or skilled personnel [14][15][16].…”

“…CGE, Crypto/Giardia Duo-Strip, RIDA QUICK Cryptosporidium/Giardia/Entamoeba Combi and Giardia/Cryptosporidium Quik Check the authors observed varying sensitivities ranging from 92 to 100% and 100% specificities for all RDT brands for the detection of Cryptosporidium when compared to ELISA, microscopy, and qPCR as gold standards [17]. In addition, these RDTs demonstrate varying performances, and some of them are not well validated for the detection of less frequent non-parvum/hominis Cryptosporidium species [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

“…They include the use of faecal smears stained by the modified Ziehl–Neelsen technique, Enzyme-linked immunosorbent assays (ELISA) and polymerase chain reaction (PCR) assays [ 13 – 14 ]. A comprehensive overview into the detection and molecular characterization of Cryptosporidium has been described elsewhere [ 15 ]…”