While diarrheal infections have always been present, identification of the rotavirus as one cause of the illness was only recently discovered. In 1973, a team of Australian researchers examining the intestinal tissues and feces of children with diarrhea through electron micrography discovered the presence of a novel wheel-shaped virus fragment. This virus was given the name “rotavirus” after the Latin word for wheel – rota.
By 1980, the CDC had declared rotavirus to be the most frequent cause of serious gastrointestinal illness in infants and toddlers and estimated that the virus caused between 20 and 60 deaths annually in the United States. It was also estimated to cause 400,000 physician visits, 200,000 emergency room visits, and between 55,000 and 70,000 hospitalizations. The infection, however, was not, and still is not, a nationally notifiable disease, therefore the exact numbers of infections and deaths from rotavirus are not known.
It was also noted in 1980 that most infants developed the illness during the winter months in non-tropical regions. Many cases of rotavirus were also preceded by respiratory symptoms which included nasal congestion, cough, and ear infections. Vomiting was found to occur prior to the onset of diarrhea, and when infants and children were given only clear fluids, vomiting ceased within 24 hours. Researchers also reported that while gastrointestinal illnesses were common, deaths were rare. In 1980, it was still not known exactly how the virus was spread but it was assumed that this occurred through the fecal-oral route. Transmission through respiratory droplets was also suspected; however, scientists had been unable to isolate the virus in the respiratory tract.
By 1983, researchers were still uncertain about the prevalence of the virus in the environment, and the incidence of infections in communities. They were also not sure how long the virus could persist in the environment, and whether it was readily transmitted through food, water, air, or additional sources. Research priorities included the development of a test that could rapidly identify the specific virus, the establishment of a universal classification for each group and type of rotavirus, and the development of a vaccine against the virus.
The most common serotypes of rotavirus were noted to be G1, G2, G3, and G4 and they accounted for more than 80 percent of all human rotavirus strains.
In January of 1989, the CDC established the National Rotavirus Surveillance System (NRSS) to collect data on rotavirus incidence and epidemiology. The surveillance system consisted of 99 laboratories who began providing data on confirmation of rotavirus. For a 23-month period, from January 1989 to November 1990, only 20 percent of the over 48,000 samples collected were positive for rotavirus. During the data collection period, rotavirus occurred most frequently in February and least often in October. Researchers also noted that approximately 500 children died each year from diarrheal disease and estimated that 20 percent of these deaths were attributable to rotavirus. Health officials also reported that hospitalizations and deaths from rotavirus were preventable by aggressive oral hydration – but stated that this strategy was under-utilized.
By 1992, public health officials reported that rotavirus infections began in western states in November and reached its peak in December and January; however, in eastern states, rotavirus activity began in January and peaked in February and March. They had no explanation for this occurrence as it was not tied to rotavirus strain variation.
Between 1986 and 1999, published studies reported that approximately 22 percent of childhood diarrhea hospitalizations were due to rotavirus. Globally, 440,000 yearly rotavirus deaths in children under the age of 5 were estimated. However, this was noted to be a significant decrease from 1985, when approximately 873,000 infants were estimated to die from the illness.
Rotavirus serotype G9 was first detected in the United States in 1987 and by 1995, it was believed to be the fifth most common serotype and was found in multiple countries including India, Brazil, Italy, and more.
