Non-enveloped Dna Viruses

Produce aggregations of incomplete and assembled viruses that usually lyse the cell  In cells that do not lyse, the viral DNA may persist in the nucleus.  Adenovirus are oncogenic in animals but none of them cause cancer in humans. 

spread from person to person by means of respiratory and ocular secretions.  most cases of conjunctival infection involve preexisting eye damage and contact with contaminated sources such as swimming pools, dusty working places and unsterilized optical instrument.  infection by adenoviruses usually occurs by age 15 in most people, and certain individuals become chronic respiratory carriers. 

the patient infected with an adenovirus is typically feverish, with acute rhinitis, cough, and inflammation of the pharynx and enlarged cervical lymph nodes  certain adenoviral strains produce an acute follicular lesion of the conjunctiva.  usually one eye is affected by a watery exudates, redness, and partial closure.  a deeper and more serious complication is KERATOCONJUNCTIVITIS, an inflammation of the conjunctiva and cornea. 

common to children caused by adenovirus  self-limiting illness of 4-5 days duration is marked by hematuria , frequent and painful urination with occasional episodes of fever, bedwetting, and suprapubic pain.  because the virus apparently infects the intestinal epithelium and can be isolated from some diarrheic stools, adenovirus is also suspected as an agent of infantile gastroenteritis.  severe cases of adenovirus infection can be treated with interferon in the early stages.  an inactived polyvated vaccinen prepared from viral antigens is an effective preventive measures used most often in military recruits. 

the two families of small nonenveloped double stranded DNA viruses  they are similar in having circular DNA and causing persistent infections and tumors.  they differ in their size and the make up of their genomes. 

a papilloma is a squamous epithelial growth commonly referred to as a wart, or verruca , caused by over 100 different strains of human papillomavirus (HPV).  some warts are specific for the mucous membranes; others invade the skin.  the appearance and seriousness of the infection vary somewhat from one anatomical region to another. 

are called common, or seed, warts.  these commonly occur in children and young adults.  plantar warts are deeper, painful papillomas on the soles of the feet; flat warts are smooth, skin colored lesions that develop on the face, trunk, elbow and knees.  a special form of verruca known as genital warts is prevalent STD and is linked to some types of cancer.

warts are transmissible through direct contact with a wart or contaminated fomites, and they can also spread on the same person by autoinoculation.  the incubation period varies from 2 weeks to more than 1 year.  papillomas are extremely common in all people and all areas of the world. 

genital warts are the latest concern among young, sexually active people.  although this disease is not new, case reports have increased to such an extent that it is now regarded as the most common STD in the U.S.  there are probably 30 million carriers of 35 types of HPV associate with genital warts.  the virus invades the external and internal genital membranes, especially of the vagina and the head of the penis 

inconspicuous bumps to extensive, branching, cauliflower-like masses called condylomata acaminata.  infection is also common in the cervix, urethra, and anal skin  most cases present with no or minimal symptoms, which can interfere with detection and diagnosis.  the most disturbing aspect of the sudden increase in HPV infection is its strong association with cancer of the reproductive tract, esp. the cervix and penis.

epithelial cells and contain two oncogenes that transform genital wart lesions into malignant tumors.  worldwide, these oncogenic HPV cause more than 500,000 new cases of cervical cancer and 200,000 deaths per year.  susceptibility to this infection and its potential for cancer can be reduced by early detection and treatment of both the patient and the sexual partner.  such early diagnosis depends on thorough inspection of the genitals and in women a Pap smear to screen for abnormal cervical cells

a biopsy and histological examination can help clarify ambiguous cases.  a sensitive DNA probe can detect HPV by means of a hybridization procedure.  this technique has the advantage of also determining the type of HPV in the infection.  the pap smear procedure is highly effective microscopic method for detecting cells that are infected or converting to cancer.  both proved valuable assessment of the patient’s risk for developing cervical cancer. 

treatment strategies for all types of warts include direct chemical application of podophyll, and physical removal of the affected skin or membrane by cauterization, freezing, or laser surgery.  immunotherapy with interferon is effective in many cases.  two vaccines aimed at the more virulent: HPV strain have been developed for use in high-risk groups.  both vaccines appear to be effective against infection and cancer. 

capable of inducing an assortment of tumors  the most important polyomaviruses are the JC virus and BK virus.  polyomaviruses are fully capable of transforming host cells and inducing tumors in experimental animals…… causes cancer in its natural host. 

infections by JC virus and BK virus are commonplace through the world.  since the majority of infections are asymptomatic or mild, not a great deal is known about their mode of transmission, portal of entry, or target cells but of the viruses.  the main complication of infection occur in patients who have ancers or immunosuppressed.  PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY (PML) is an uncommon but generally fatal infection by JC virus that attacks accessory brain cells and gradually demyelinizes certain parts of the cerebrum. 