人畜共患隐孢子虫分子流行病学英文简要

Two types of techniques are used in the subtypping (MLT), variations in microsatellites and minisatellites are assessed on the basis of length variations using polyacrylamide gel electrophoresis or the GeneScan technology (Ngouanesavanh et al., 2006; Tanriverdi et al., 2006; Tanriverdi and Widmer, 2006; Leoni et al., 2007; Morrison et al., 2008).

However, in addition to variations in the number of trinucleotide
repeats, there are extensive sequence differences in the non-repeat regions, which categorize C.parvum and C. hominis each to several

Last three years revealed the use of SSU rRNA tools in 100 (86%) of 116 publications.

In particular, a PCR-RFLP tool that targets an ~830-bp fragment of
2. Recent developments in molecular epidemiologic tools

Small subunit (SSU) rRNA based tools are now generally used in
genotyping Cryptosporidium in humans, animals and water samples.
diagnostic tools do not have the ability to differentiate sources of parasites.

In the last decade, however, numerous molecular biological techniques
4. Cryptosporidium species/genotypes in humans
5. Cryptosporidium parvum subtypes and zoonotic transmission
5.1. Cryptosporidium parvum subtypes in animals

Gp60 is located on the surface of apical region of invasive stages of the parasite, and is one of the dominant targets for neutralizing antibody responses in humans(O’Connor et al., 2007).

The gp60 gene is similar to a microsatellite sequence by having
tandem repeats of the serine-coding trinucleotide TCA, TCG or TCT at
the 50 (gp40) end of the gene.
have been developed to detect and differentiate Cryptosporidium spp.
at species/genotype and subtype levels..

This review discusses mostly recent progresses in cryptosporidiosis molecular epidemiology since 2006.
them.

The former results in the failure in detecting many concurrent
Molecular epidemiology of cryptosporidiosis: An update
1.Introduction
2. Recent developments in molecular epidemiologic tools 3. Cryptosporidium parvum infections in farm animals
the 60 kDa glycoprotein (gp60, also called gp40/15).

Sequence analysis of gp60 gene is widely used in Cryptosporidim subtyping because of its sequence heterogeneity and relevance of parasite biology. It is the most single polymorphic marker identified so far in the Cryptosporidium genome(Gatei et al., 2006a; Leoni et al., 2007; Wielinga et al., 2008).
5.2. Cryptosporidium parvum subtypes in humans and zoonotic Transmission
6. Cryptosporidium hominis infections 7. Human infections with other Cryptosporidium spp 8. Conclusion

Other C. parvum subtype type families, especially IIc (formerly known as Ic), have been so far only found in humans (Alves et al., 2003; Xiao and Feng, 2008).
cryptosporidiosis.

In areas with both IIa and IId, such as Spain, IIa subtypes preferentially
infect calves whereas IId subtypes preferentially infect lambs and goat kids (Quilez et al., 2008a,b).
the gene and uses SspI and VspI restrictions for genotyping (Xiao et al., 1999, 2001) is commonly used, being reported in 70 (60%)
publications.

Tools based the oocyst wall protein (COWP) gene were used in only 23 of the 116 original and other genes were rarely used.
1. Introduction

Cryptosporidium infect various animals and the ubiquitous presence of Cryptosporidium oocysts in environment, humans can acquire Cryptosporidium infections through several transmission routes, such as direct contact with infected persons or animals and ingestion of

Subtyping tools have been used extensively in studies of the
transmission of C. hominis in humans and C. parvum in humans and
ruminants.

One of the popular subtyping tools is the DNA sequence analysis of
subtype families.

Within each subtype family, subtypes differ from each other mostly in the number of trinucleotide repeats (TCA, TCG or TCT microsatellite).
The second type of typing techniques, multilocus sequence typing (MLST,多位点序列分型), relies on the detection of genetic

heterogeneity by DNA sequencing of the amplified PCR
only the dominant genotype in the specimen because of the inherent nature of exponential amplification by PCR .

On the other hand, all narrowly specific genotyping and subtyping tools detect only C. hominis, C. parvum and species or genotypes related to
3.1. Cryptosporidium parvum in cattle 3.2. Cryptosporidium parvum in sheep and goats 3.3. Cryptosporidium parvum in pigs 3.4. Cryptosporidium parvum in other farm animals
products(Cama et al., 2006b; Gatei et al., 2006a, 2007, 2008).

No matter which PCR tool is used in genotyping or subtyping
Cryptosporidium, all broadly specific tools have the problem of detecting

Thus, it is possible to link biologic characteristics of the parasites and clinical presentations with the subtype family identity.

Some of the C. parvum subtype families, such as IIa and IId, are found in both humans and ruminants, responsible for zoonotic
contaminated food and water .

The relative importance of these transmission routes in the epidemiology of
cryptosporidiosis is not entirely clear, largely due to the fact that traditional