Abnormal Development - Measles Virus

Notice - Mark Hill

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Introduction

Rubella and measles elimination in the Americas

Measles (rubeola) is a paramyxovirus appearing mainly as a respiratory viral infection, clinically different from Rubella. A single-stranded RNA virus which is highly contagious. Before measles vaccination (USA 1963) more than 90% of children had an infection before puberty and in developing countries it is still a common and often fatal childhood disease. Childhood immunisation and immunity persists in only about 80% of adults.

Pregnancy effects of measles results in a higher risk of premature labor, spontaneous abortion, low-birth-weight, and possibly rare cases of birth defects with no definable pattern of malformation.

Some Recent Findings

Rapid titration of measles and other viruses: optimization with determination of replication cycle length"Measles virus (MV) is a member of the Paramyxoviridae family and an important human pathogen causing strong immunosuppression in affected individuals and a considerable number of deaths worldwide. Currently, measles is a re-emerging disease in developed countries. MV is usually quantified in infectious units as determined by limiting dilution and counting of plaque forming unit either directly (PFU method) or indirectly from random distribution in microwells (TCID50 method). Both methods are time-consuming (up to several days), cumbersome and, in the case of the PFU assay, possibly operator dependent. ...Overall, performing the assay takes only 24-30 hours for MV strains, 12 hours for VSV, and 52 hours for HIV-1. The step-by-step procedure we have set up can be, in principle, applicable to accurately quantify any virus including lentiviral vectors, provided that a virus encoded gene product can be detected by flow cytometry." Since January 2011 Romania has been experiencing a measles outbreak with 2,072 cases notified in 29 of the 42 Romanian districts. "This report underlines once more the need for additional measures targeting susceptible populations to achieve high vaccination coverage with two doses of measles-mumps-rubella vaccine." The measles virus replication cycle "This review describes the two interrelated and interdependent processes of transcription and replication for measles virus. First, we concentrate on the ribonucleoprotein (RNP) complex, which contains the negative sense genomic template and in encapsidated in every virion. Second, we examine the viral proteins involved in these processes, placing particular emphasis on their structure, conserved sequence motifs, their interaction partners and the domains which mediate these associations."

Virus Structure

thumb|Identical genotype B3 sequences from measles patients in 4 countries, 2005.[5] Lineage: Viruses; ssRNA viruses; ssRNA negative-strand viruses; Mononegavirales; Paramyxoviridae; Paramyxovirinae; Morbillivirus; Measles virus

• ssRNA; linear; Length: 15,894 nt Measles virus, complete genome
• virus replication involves a viral RNA-dependent RNA polymerase (vRdRp), using as a template a nucleocapsid (NC) made of a single strand of RNA in tight complex with the nucleoprotein (N).
• negative-strand genome contains six transcription units encoding the N, phospho (P), matrix (M), fusion (F), hemagglutinin (H), and large (L) or polymerase protein.
• each N protein binds to 6 nucleotides.
• the N polymer entirely covers the 15,894-nucleotide genome.
• 23 known measles genotypes.

Model of cell virus RNA accumulation

The following 5 -step model has been described for cell virus accumulation following hours post-infection (hpi)

1. 0 to ~5 hpi - incoming viral RNA-dependent RNA polymerase (vRdRp) initiated primary transcription from every gene with no detectable lag phase.
2. ~5 to ~12 hpi - mRNA accumulates exponentially.
3. ~12 to ~24 hpi - mRNAs, genomes, and antigenomes accumulate exponentially because of the increase of both newly available template and vRdRp.
4. ~24 to ~30 hpi - genomes and antigenomes continue to accumulate exponentially at the same rate, whereas the accumulation of the transcripts slows down.
5. 30+ hpi - genome and antigenome accumulation slows down, and the cell content in viral transcripts tends to decrease.

Vaccination

Japan - first introduced to Japan in 1966 and adopted in the national regular immunization program from 1978.

References

Textbooks

• Medical Microbiology. 4th edition. Baron S, editor. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Medical Microbiology- Measles
• Molecular Biology of the Cell. 4th edition. Alberts B, Johnson A, Lewis J, et al. New York: Garland Science; 2002. Viruses Exploit Host Cell Machinery for All Aspects of Their Multiplication
• Disease Control Priorities in Developing Countries. 2nd edition. Jamison DT, Breman JG, Measham AR, et al., editors. Washington (DC): World Bank; 2006. Chapter 20Vaccine-preventable Diseases

Reviews

<pubmed> 19757257</pubmed>

<pubmed>1923230</pubmed> <pubmed>17999132</pubmed> <pubmed>16480851</pubmed>

Articles

<pubmed>12850161</pubmed>

Search Pubmed

Search Pubmed: Measles Virus | rubeola | Congenital rubeola Infection

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Cite this page: Hill, M.A. (2024, May 7) Embryology Abnormal Development - Measles Virus. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Abnormal_Development_-_Measles_Virus

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G