Cryspovirus is a genus of viruses, in the family Partitiviridae.[1] Protists serve as natural hosts. There is only one species in this genus: Cryptosporidium parvum virus 1.[2] [3]
Cryptosporidium, a genus of Apicomplexan parasites, is known to cause human diarrhealillness. A bi-segmented dsRNA virus linked with Cryptosporidium was discovered andfound to have similarities with picobirnaviruses and partitiviruses. This discovery led to theidentification of a distinct virus called Cryptosporidium parvum virus 1 (CSpV1). It wassuggested to be the sole partitivirus found in a protozoan host. Based on this, a new genusnamed Cryspovirus was proposed within the Partitiviridae family, which was subsequentlyapproved by the ICTV Executive Committee in 2009. CSpV1, also known as Cryspovirus, isbelieved to be transmitted intracellularly through Cryptosporidium oocysts and is linked withpersistent, mostly non-virulent infections. The virus features isometric virions and has a genomecomposed of two separate dsRNA molecules encoding RdRp and CP. Notably, the CP ofCSpV1 is smaller than that of other partitiviruses, indicating a unique capsid structure.Biologically, CSpV1 appears to be primarily transmitted through intracellular methods and isassociated with non-aggressive infections. Its impact on altering Cryptosporidium'spathogenicity remains to be fully understood. CSpV1 exhibits unique genomic and codingcharacteristics, with its dsRNA segments having distinct nucleotide sequences (often detectedvia PCR). The virus is believed to employ a non-standard mechanism for translation, andconserved sequences at the 3′ ends of its dsRNAs might be involved in replication or packagingprocesses. CSpV1 holds practical significance in the detection of Cryptosporidium incontaminated water supplies and in the epidemiological monitoring of Cryptosporidiuminfections. [4] [5] [6] [7]
Viruses in Cryspovirus are non-enveloped, with icosahedral geometries, and T=1 symmetry. The diameter is around 30-35 nm. Genomes are linear and segmented, around 2.1kb in length. The genome codes for 2 proteins.[2] [3]
| Genus | Structure | Symmetry ! | Capsid | Genomic arrangement | Genomic segmentation | |
|---|---|---|---|---|---|---|
| Cryspovirus | Icosahedral | T=1 | Non-enveloped | Linear | Segmented |
Viral replication is cytoplasmic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the double-stranded RNA virus replication model. Double-stranded RNA virus transcription is the method of transcription. Protists serve as the natural host.[2] [3]