YOU GIVE ME FEVER....It should be noted that a huge majority of the diseases caused by reoviruses are characterized by febrile illness.

Rotaviruses

Rotaviruses are exceedingly ubiquitous, found throughout the world in nearly every country. The rotaviruses are divided into six serogroups, but most of the human rotaviruses infecting the population are classified into group A. It is type G1 of this serogroup that causes severe rotaviral illness. Rotavirus infection is responsible for over one million deaths in the developing world per year, and for 500 deaths per year in the United States.

The incubation period for rotavirus infection is 1 to 3 days, and the patient is infectious during this period. There is some seasonality to the infection, and it appears to peak in the winter in the temperate zones. Though the rotavirus is known to be transmitted by the fecal-oral route, this seasonality and the documentation of patients with respiratory symptoms raises the possibility that rotaviruses might be transmitted by the aerosol route.

The virus infects primarily infants aged 6 to 24 months. This is the age group which most often displays clinical symptoms&emdash; silent infection is seen in most cases of neonatal infection and in many cases of child or adult infection. Symptoms include vomitting followed by severe diarrhea. The diarrhea lasts for 4-5 days and if the patient is not well-nourished, severe dehydration can lead to death. These rotaviruses are the most prolific cause of infant gastroenteritis in the world. Rotaviruses present an issue of international importance, as death can be easily prevented by the administration of electrolytes and water-- this treatment must be disseminated through the developing world. The background is made up of the electron micrograph image of a rotavirus, illustrating its characteristic wheel-like apperancel. To view the entire micrograph image, click here for a great image courtesy Professor Stewart McNulty.

Orthoreoviruses

It is not conclusively known to cause clinically significant disease in humans, though they are known to infect a variety of mammalian species. It is thought that the orthoreoviruses might be responsible for mild upper respiratory syndromes, but that has not been proven. It is believed that the orthoreoviruses cause subclinical infection in the majority of people as most people are seen to have antibodies to all three of the serotypes identified. Virus is shed in the feces.

Coltiviruses

Colorado Tick Fever virus: Geographically, this virus is found in the Rocky Mountains of the United States and Canada. It is an arbovirus, and its vector is the wood tick Dermacentor andersoni. After an incubation period of about four days, the disease is characterized by a sudden onset, including fever, retroorbital pain, myalgia in the legs and back, and leukopenia. The fever has been dubbed "saddle-back" due to a remission of 1 to 3 days after which more fever and more severe symptoms follow. The disease is severe enough to send 20% of infected patients to the hospital and also to indicate the remote possibility of death. Convalescence may be prolonged, and hemorraghic fevor and/or encephalitis are seen in about 5% of the patients (mostly children).

Sunday canyon virus: A virus seen in North America, Sunday canyon virus is thought to be tick-borne (not conclusive) and causes febrile illness in humans.

Eyach virus: Found in Europe, especially, Czechoslovakia, the Eyach virus is tick-borne and potentially causes encephalitis and polyneuritis, though this has not been proven.

Banna virus: Seen mainly in China, Banna virus is associated with febrile illness and encephalitis. It is not known yet what the vector is, but it is an arbovirus and ticks and mosquitoes are candidates. Zoonotic transmission is also a possibility.

Orbiviruses

Orungo virus: Found in tropical Africa, Orungo is transmitted by a mosquito vector. There is not a great deal of information known about the virus, but infection appears to be fairly widespread although often subclinical or very mild. It is associated with febrile illness.

Lebombo virus: Only a single case has led to viral isolation, and the virus is associated with fever. It has been seen in Nigeria, and is linked to several different mosquitoes as possible vectors as well as a rodent.

Changuinola virus: Associated with febrile illness in Panama, the incidence and distribution of Changuinola is unknown. It seems to be associated with phlebotomine flies as a possible vector.

Kemerovo viruses: Seen mainly in the Siberian region of Russia, the Kemerovo viruses cause febrile illness and possibly meningoencephalitis in humans. An arbovirus, Kemerovo is tick-borne and has also been linked to Oklahoma Tick Fever in the United States, though this etiology has not been conclusively shown.