Articles on Medical Diseases and Conditions

Entries Tagged ‘Viral Infections’

Coronaviruses

These are RNA viruses that predominately affect infants and young children, causing gastroenteritis and sometimes necrotizing enterocolitis. Diarrhea is usually present. Diagnosis is by electron microscopy of stool specimens. Some homemade EIA serologic tests have been described. This virus appears at present to be found in only a relatively small proportion of gastroenteritis patients.

Calciviruses (Non-Norwalk)

These RNA viruses cause gastroenteritis primarily in infants and young children, similar clinically to rotavirus infection; sometimes as severe as rotavirus but often somewhat milder. Cluster outbreaks in institutions and sporadic occurences have been reported. One report indicated that calciviruses cause 3% of gastroenteritis in U.S. day-care centers. Some cluster infections in adults from contaminated […]

Astroviruses

These RNA viruses are said to cause about 5% of infant gastroenteritis (range, 2%-9%). Symptoms are various combinations of vomiting and diarrhea, lasting 0.5-4.0 days. They originally were identified by EM of stool specimens. Culture is also possible using special procedures. EIA test methods using homemade reagents have been described.

Norwalk Viruses

These are small round RNA viruses. There are some similarities to calciviruses. Infection predominately involves adults, adolescents, and older children. About 55%-75% of adults have antibodies against this virus. Third-world countries have a higher incidence of antibody. Epidemiologically, disease in the United States usually occurs in clusters (outbreaks); reviews found 34%-47% of such gastroenteritis outbreaks […]

Enteric Fastidious Adenoviruses

These DNA viruses (unlike other adenoviruses) could not be cultured using standard virus culture systems. The most frequent are types 40 and 41. These enteric adenovirus species are the second most common cause of severe gastroenteritis in young children (after rotavirus), comprising about 10%-15% of cases (range, 5%-52%). It has also been the second or […]

Rotavirus

These DNA viruses (unlike other adenoviruses) could not be cultured using standard virus culture systems. The most frequent are types 40 and 41. These enteric adenovirus species are the second most common cause of severe gastroenteritis in young children (after rotavirus), comprising about 10%-15% of cases (range, 5%-52%). It has also been the second or […]

Viruses Predominately Associated with Gastroenteritis

Rotavirus is an RNA virus in the Reoviridae family. It infects many types of mammals and birds as well as humans. Rotavirus is the most frequent cause of infectious diarrhea of infants and young children. Symptoms include diarrhea (65%-100% of cases), fever, and vomiting (48%-92% of cases). Vomiting may precede diarrhea (usually by less than […]

Arthropod-Borne Viruses (Arboviruses)

As the name suggests, these are viruses transmitted to humans by arthropods (mostly by mosquitos, but some by ticks). There are three groups of diseases: CNS infections (e.g., encephalitis and aseptic meningitis); hemorrhagic fever (e.g., yellow fever and dengue); and nonspecific fever (e.g., dengue and Colorado tick fever). Of encephalitis cases, the most common agent […]

Creutzfeldt-Jacob (C-J) Disease

This disease is also known as spongiform encephalopathy (describing the typical microscopic changes in affected brain tissue). It is transmitted by a protein agent known as a prion (proteinaceous infectious agent) that resembles one of the genes in structure. About 90% of cases are sporadic and 5%-15% are hereditary with autosomal dominant transmission. In the […]

Jc Virus Infection

The JC virus belongs to the polyoma virus group of the papovavirus family, which are double-stranded DNA viruses without an envelope. BK virus is also in the polyoma virus group. It appears that infection by both viruses occurs during childhood or adolescence, with about 50% of the population demonstrating antibody before adulthood, rising later to […]