[1] CVV is an enveloped arbovirus, nominally 80–120 nm in diameter, whose genome is composed of three single-stranded, negative-sense RNA segments.

[1][2] The large segment of related bunyaviruses is approximately 6800 bases in length and encodes a probable viral polymerase.

The small segment utilizes an open reading frame with alternative initiation sites to encode two proteins.

[5] The medium segment encodes 2 type 1 integral transmembrane glycoproteins, Gn and Gc, as well as a non-structural protein Nsm.

A heterodimer of integral transmembrane proteins Gn and Gc form spikes on the surface of the virus particle.

Transcription of the tripartite genome is terminated by a strong hairpin loop sequence at the end of each segment.

Six days after the onset of the illness more severe symptoms appeared including confusion, tachycardia (elevated heart rate), a rash, bilateral conjunctivitis and meningismus.

After three days the patient was released from the hospital; he reported feeling fully recovered four months later, though he experienced headaches more frequently than usual.

Very few human cases have been reported despite its wide geographic distribution and the large number of mosquito species that transmit it.

[15] Cache Valley virus is the most common Orthobunyavirus in North America,[17] and while isolated in 1956, was only linked to disease in Texas in 1987 during a large occurrence of aborted and malformed lambs in a sheep flock.

[18] The virus does not only infect sheep, however, as In 2002 a survey conducted in 22 states showed 28% of cattle expressed specific antibodies to CVV.

With viraemia lasting 1 to 3 days, they are easily able to spread the virus to vectors including Culicoides midges and Aedes, Anopheles, Coquillettidia and Culiseta group mosquitoes.

[17] While the virus is able to replicate in adult animals, besides a slight febrile response in some cases, there are no known symptoms of infection.

[21] However, if the animal is pregnant and not protected by antibodies from a previous infection, Cache Valley virus can be very lethal to a developing fetus.

[17] Death of the fetus usually occurs between 27 and 35 days gestation, when the central nervous system tissues are most susceptible.

[23] The most common musculoskeletal deformations include arthrogryposis and greatly reduced muscle mass, with the most severe cases having torticollis, scoliosis, and kyphosis.

When the virus crossed the placenta and infected the developing fetus, it showed a tropism for the immature fetal cells of the central nervous system and skeletal muscle.

[21] Hydranencephaly has also been identified in goat kids with presumptive in utero infection with Cache Valley virus.

[27] The most effective method of protecting ruminants from CVV is to minimize their exposure to mosquito-infested areas during and shortly after breeding season.

[27] Concerning the safety of humans, it is advised that necessary precautions be taken, such as, putting on mosquito repellent or layers of clothing, when being exposed to mosquito-infested areas.