St. Louis Encephalitis
Elizabeth Salas &
Humans and Viruses
Human Biology 115A
Date completed: 3/6/00
Sapporo virus is the type species of "Sapporo-like virus." It was first recognized in an outbreak of acute gastroenteritis that occurred in an orphanage in Sapporo, Japan. Other Sapporo-like viruses include Manchester and Human Calicivirus. These viruses exhibit similar clinical manifestations. The "typical" caliciviruses are associated with gastroenteritis in infants and young children.Incubation
The incubation period of Sapporo virus is 1-3 days. Symptoms usually persist an average of 4 days.Epidemiology
Transmission of Sapporo virus occurs through fecal-oral route. Outbreaks of Sapporo viruses and Sapporo-like viruses are associated with fecal contamination of food or water (e.g., consumption of raw or undercooked shellfish that were harvested from contaminated water) and discharge of sewage into drinking water supplies or recreational water areas. Secondary spread occurs between groups in close contact, such as within a household or school.
Sapporo virus particles are found in both symptomatic and asymptomatic individuals. They have been established as enteric pathogens. Studies have suggested that "typical" caliciviruses are a minor cause of clinically significant disease. Unlike Norwalk virus and Norwalk-like viruses, SLVs is associated with long-lived immunity.Symptomatology and Outcome
Common symptoms of Sapporo virus and Sapporo-like viruses include diarrhea and vomiting. Though upper respiratory symptoms have been reported among young children, these are often causal symptoms related to common viral infections in this age group. Symptoms lasts for an average of 4 days.
Infants and young children often exhibit clinical symptoms, while neonatal infections are often subclinical. Adults and elderly patients rarely experience outbreaks. Outbreaks among adults and the elderly might be associated with waning immunity.Pathology and Pathogenesis
It is suggested that Sapporo virus may undergo a similar pathology as SRSVs. Yet unlike SRSVs, there have been few studies on the pathology of Sapporo and SLVs. Comparing Sapporo to other "diarrhea viruses" it is suggested that Sapporo replicates in the mucosal cells that line the villi of the small intestine.Prevention and Management
Prevention and management of Sapporo virus and SLVs are similar to those for Norwalk and Norwalk-like viruses. These measurements included basic hygiene and sanitation measures. A clean water supply is central in the prevention of outbreaks. Likewise, food should be completely cooked or peeled to prevent food contamination.