New world arena viruses are further broken down into three clades, A, B, and C. The Guanarito arena virus belongs to clade B and is the cause of VHF. On the biosafety level scale of one to four, with four causing the most risk, the viruses causing hemorrhagic fevers have been assigned a four by the CDC. Host
The short-tailed cane mouse, the main host of GTOV, is native to western Venezuela and resides in large numbers in tall grass, cultivated agricultural fields, human homes, and outbuildings. It is speculated that demographic and ecological changes in the rural areas increased the frequency of contact between humans and infected rodents such that VHF emerged. History
From September 1989 through December 2006, the State of Portuguesa recorded 618 cases of VHF. Nearly all of the cases were individuals who worked or lived in Guanarito during the time they became infected. The case fatality rate was 23.1%.Because the virus is contracted by aerosol dissemination, concern arose shortly after the first cases emerged in 1989 due to fear of biological warfare. Potential biological terrorism agents were identified and categorized in 1999 by the Centers for Disease Control and Prevention (CDC) as part of the Congressional initiative to further response capabilities to biological weapons. Arenaviruses causing hemorrhagic fevers, along with a genus of virus called filoviruses, were categorized in Category A; these are pathogens with the highest potential impact on public health safety.
Articular branches - There are three articular branches arises from the upper part of the fossa: superior medial genicular nerve (located on the surface of medial condyle of femur, middle genicular nerve (pierces the posterior capsule of the knee joint to supply the structures located in the intercondylar notch of the femur, and inferior genicular nerve (runs along the upper border of the popliteus to reach the medial condyle of tibia). Back of the leg
At the inferior angle of the popliteal fossa, tibial nerve passes deep to the tendinous arch of soleus to enter the back of the leg. In the leg, it runs downwards and medially to reach the posteromedial side of the ankle, midway between the medial malleolus and medial tubercle of the calcaneum. It terminates deep to the flexor retinaculum at the origin of the abductor hallucis by dividing into medial and lateral plantar nerves to supply the foot. The tibial nerve gives off several branches to supply the back of the leg:
Muscular branches - Supplies tibialis posterior, flexor digitorum longus, flexor hallucis longus, and deep part of soleus. Cutaneus branches - The medial calcaneal nerve pierces the flexor retinaculum to supply the skin of the back and lower surface of the heel. Articular branches - Supplies the ankle joint

Foot
In the foot, the nerve terminates by dividing into medial and lateral plantar branches. Medial plantar nerve - It is the larger terminal branch of the tibial nerve. It passes between the abductor hallucis and flexor digitorum brevis to divide further into branches.