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Adino viruses are a group of double-stranded DNA viruses that can infect a wide range of organisms, including humans, animals, and plants. The name “Adino” comes from the Greek word “adinoun,” which means “indistinct.” This is because the viruses were originally classified as adenoviruses due to their similarity in structure and replication to human adenoviruses. However, Adino viruses differ from adenoviruses in several important ways, including their genomic organization, protein composition, and host range.
Table of Contents
History:
The first Adino virus was isolated in 1963 from a diseased African green monkey. Since then, Adino viruses have been found in a variety of animal and plant species, including humans, cows, pigs, horses, dogs, cats, chickens, and wheat. The viruses are commonly associated with respiratory, gastrointestinal, and eye infections in humans and animals, although some strains can also cause more severe diseases, such as hepatitis and encephalitis.
Structure and genome:
Adino viruses are non-enveloped viruses that range in size from 60 to 80 nanometers in diameter. They have an icosahedral capsid that is composed of 252 capsomeres, each of which is made up of three proteins: hexon, penton base, and fiber. The capsid contains the viral genome, which consists of a linear, double-stranded DNA molecule of approximately 30-40 kilobase pairs. The genome is organized into early and late regions, each of which contains several open reading frames (ORFs) that encode for various viral proteins.
Replication cycle:
Adino viruses enter host cells by binding to specific receptors on the cell surface, which triggers endocytosis of the virus. Once inside the cell, the virus uncoats its genome and transports it to the nucleus, where it replicates and expresses viral genes. Early gene products are involved in viral DNA replication and modulation of host cell functions, while late gene products are responsible for capsid assembly and virus release. Adino viruses are released from infected cells by cell lysis or by budding through the plasma membrane.
Clinical significance:
Adino viruses are a common cause of respiratory, gastrointestinal, and eye infections in humans, particularly in young children and immunocompromised individuals. The viruses are highly contagious and can be spread through respiratory secretions, fecal-oral transmission, and contact with contaminated surfaces. Symptoms of Adino virus infection typically include fever, cough, sore throat, diarrhea, and conjunctivitis, although more severe infections can result in pneumonia, hepatitis, and encephalitis. Treatment of Adino virus infections is primarily supportive, with antiviral drugs having limited efficacy.
Research:
Research on Adino viruses has focused on understanding their pathogenesis, epidemiology, and molecular biology. Studies have investigated the mechanisms by which Adino viruses enter host cells, replicate their genome, and modulate host immune responses. Other studies have explored the genetic diversity and evolution of Adino viruses, as well as their interactions with host cells and tissues.
One area of research that has gained increasing attention in recent years is the development of Adino virus-based vectors for gene therapy and vaccine delivery. Adino virus vectors are able to efficiently transduce a variety of cell types and can be engineered to express therapeutic genes or vaccine antigens. Several Adino virus-based vectors have been developed for the treatment of genetic disorders, cancer, and infectious diseases, including HIV, influenza, and COVID-19.
Challenges:
Despite the potential of Adino virus-based vectors for gene therapy and vaccine development, there are several challenges that need to be addressed. One major challenge is the immune response to Adino viruses, which can limit the efficacy and safety of Adino virus-based therapies. Adino viruses can activate innate immune pathways and induce neutralizing antibodies, which can prevent subsequent vector administration and reduce therapeutic efficacy.
Another challenge is the development of Adino virus vectors with improved targeting and specificity. Adino viruses can infect a variety of cell types, which can lead to off-target effects and toxicity. Therefore, efforts are underway to develop Adino virus vectors with cell-type specific promoters and enhancers, as well as to engineer the capsid proteins to alter their tropism and receptor specificity.
Conclusion:
Adino viruses are a diverse group of double-stranded DNA viruses that can infect a wide range of organisms, including humans, animals, and plants. The viruses are associated with a variety of diseases, ranging from mild respiratory and gastrointestinal infections to more severe hepatitis and encephalitis. Although Adino viruses are highly contagious and can cause significant morbidity and mortality, there is currently no effective vaccine or antiviral therapy available for their prevention or treatment.
