Parvovirus B19

From MicrobeWiki, the student-edited microbiology resource

Background

The life cycle of Canine Parvovirus. Photo credit: [1]

By Grace Potter

Parvovirus B19 is the only member of the Parvoviridae family that has been found to infect human hosts.[1] It was discovered in 1974, when a research group looking at hepatitis B surface antigens found a serum sample with unexpected results.[1] Another lab in Japan described a similar virus in 1979 that they called "Nakatami".[1] When compared, the two were found to be identical.[1] In 1985 this virus was officially recognized as a member of the Parvoviridae family due to its similarities in genome size and density.[1]

Infection by Parvovirus B19 (Parvo B19V) causes many diseases, including "fifth disease" in children, aplastic crisis for people with hemolytic anemia, anemia in immunocompromised patients, acute or chronic arthropathy in adults, and fetal hydrops in pregnant women.[2][3] Changes in the genome are potentially responsible for the wide variation of clinical presentations associated with B19V infection.[2]

Section 1

Include some current research, with at least one figure showing data.

Parvoviridae

[4]

[5]

[6]

Genome Structure

The Parvovirus genome is a single strand of DNA with 5,596 nucleotides, 4,830 of which are coding regions.[1] This region contains 2 large open reading frames.[1] One large non-structural protein is coded by one open reading frame, NS1, and the second reading frame codes for 2 capsid proteins, VP1 and VP2.[1] The sequences of B19V isolates do not exhibit much genetic variation with NS1 showing incredibly high conservation, and 2-3% divergence in VP1 and VP2 regions.[1] When examining isolates from patients with chronic infection due to B19V, there is a much higher degree of variation at DNA and protein levels.[3]

There are now 3 distinct genotypes recognized as Parvovirus B19 including: (1) all prototype B19V isolates, (2) A6 and LaLi isolates, and (3) V9 and related isolates.[2] These variations in the genome are potentially responsible for the variety of host responses to infection.[2] In a study on 3 isolates of the 3 genotypes, the A6 isolate did not produce R5, R7, and R9 mRNAs, which are important in the production of VP1 and VP2 as coordinating mRNAs.[2] There was also an increase in sequence divergence between the 3 isolates. They found that B19V NS1-V9 and B19V NS1-A6 diverge by 13% from B19V NS1, but only diverge by 6% in protein structure.[2]

The V9 (A) and A6 (B) genomes are depicted with transcriptional landmarks. These include promoters (ie. P6), splice donors (D), and splice acceptors (A), as well as the ORFs encoded and their predicted protein sizes in kDa. Photo credit: [2]

Section 3

Include some current research, with at least one figure showing data.

Section 4

Conclusion

References



Authored for BIOL 238 Microbiology, taught by Joan Slonczewski,at Kenyon College,2024