Hepatitis A, one of the oldest diseases known to humankind, is a self-limited disease which results in fulminant hepatitis and death in only a small proportion of patients. However, it is a significant cause of morbidity and socio-economic losses in many parts of the world.
Transmission of HAV is typically by the fecal-oral route. And infections occur early in life in areas where sanitation is poor and living conditions are crowded. With improved sanitation and hygiene, infections are delayed and consequently the number of persons susceptible to the disease increases. Under these conditions explosive epidemics can arise from fecal contamination of a single source.

Dengue viruses, transmitted by the mosquito, Aedes aegypti and Aedes albopictus mosquitoes, are widely distributed throughout the tropical and subtropical areas of the world. There are four known distinct serotypes (dengue virus 1, 2, 3 and 4). NS1 is a highly-conserved glycoprotein that is present at high concentrations in the sera of Dengue infected patients during the early clinical phase of the disease. NS1 antigen is found from the first day and up to 9 days after onset of fever in sample of primary or secondary dengue infected patients.

GAS (Group A streptococcus) is one of the most important causes of acute upper respiratory track infection. Hardly diagnosis and treatment of Group A Streptococcal pharyngitis has been shown to reduce the severity of symptoms and serious compications such as rheumatic fever and glomerulonephritis. Conventional identification procedures for GAS from throat swabs involve the isolation and subsequent identification of viable pathogen techniques that require 24~48 hours or longer for results.

Rotavirus is the most common cause of severe, dehydrating diarrhea among children worldwide. Scientists have described seven rotavirus groups (A to G). Only groups A, B, and C infect humans. Group A, which has multiple strains, causes the majority of childhood infections. Although human of all ages are susceptible to rotavirus infection, children 3 to 24 months of age account for the vast majority of severe infections. A person with rotavirus diarrhea often excretes large amounts of virus, which can spread readily through contaminated hands. Rotavirus, a hearty virus that survives easily in the environment, can also be transmitted through contaminated objects, water or food.

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