Advanced Biotechnologies Inc introduces new Enteroviruses RNA controls
ABI Offers two new EV PCR RNA Controls to Aid Research Investigations on Enteroviruses
Human enteroviruses (EVs) are non-enveloped, positive sense, single-stranded RNA (7.0-8.5 kb) viruses and are 22-30 nm in diameter. EVs belong to the family Picornaviridae ; there are 62 immunologically distinct serotypes that infect humans, and these are classified into 5 species: A, B, C, D, and poliovirus (Seventh report of ICTV, Virus Taxonomy, 2000). These viruses are referred to as EVs because they primarily infect the enteric tract, but they are seldom associated with the enteric disease.
EVs are found worldwide and may cause sporadic and epidemic outbreaks. In tropical climates, EV infections are diagnosed throughout the year; but in temperate climates, EVs are found mainly in summer and fall. In the USA, nonpolio EVs are responsible for an estimated 10-15 million symptomatic infections.
Infections caused by EVs are frequently asymptomatic, but may cause serious and even fatal disease. EVs are the major cause of acute febrile illness in infants and young children, and they are most commonly associated with aseptic meningitis and acute myocarditis. Clinical diseases caused by EVs are not predictable, because a single EV serotype can cause multiple clinical symptoms, and a single symptom may be caused by different EV serotypes. Major clinical manifestations caused by EV infections are:
- acute hemorrhagic conjunctivitis (e.g., EV 70)
- severe infections of the central nervous system leading to paralysis because of their neurovirulence property (e.g., polioviruses)
Infections are spread mainly by fecal-oral route, but can also be spread by fomites or airborne routes. EVs are excreted in the stool for long periods after infection and when sanitary conditions are poor, can contaminate drinking and swimming pool waters. Laboratory diagnosis of EV infections is important
1) because they may cause serious diseases that may be amenable to antiviral therapy, and
2) for epidemiological monitoring of their prevalence in different geographical areas.
Their diagnosis can be achieved by:
- detection of antigens by IFA
- virus isolation and identification by typing (NT)
- serological assays (CF, ELISA) for the detection of antibodies
- nucleic acid detection
Although the 'gold standard' for the diagnosis of EV infection is virus isolation in cell cultures followed by typing with neutralizing antisera (NT), it is time-consuming, expensive, and may give false negative results. There may be EV isolates that cannot be typed and/or EVs that cannot be readily propagated in cell cultures. Also, serological tests like ELISA may detect antibody response to an earlier EV infection rather than an acute or recent infection.
A more sensitive diagnostic tool is Amplification of EV-RNA by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). RT-PCR has a higher sensitivity than EV isolation from fecal specimens, cerebrospinal fluids, serum/plasma, heart and skeletal muscles. RT-PCR has been successfully used for the group- or type-specific identification of EVs from clinical specimens, including differentiation between poliovirus vaccine strains and wild-type strains.
The search for an effective antiviral drug for acute EV infection is ongoing. However, there have been clinical trials in which 'Acyclovir' has helped patients infected with HFMD, and 'Pleconaril' has demonstrated efficacy in patients with meningoencephalitis and neonatal enteroviremia.
To aid your research investigations on the association of EV infections with human diseases and/or molecular epidemiological studies, ABI offers the following two new EV-PCR RNA controls:
Coxsackie B 2 Viral RNA (Cat. #08-819-000)
Echovirus Type 11 Viral RNA (Cat. #08-820-000)
Source : Advanced Biotechnologies Inc. View Company Information
Posted on June 18, 2003