Viral Hemorrhagic Fevers

Bunyavirus-Related Hemorrhagic Fevers

Crimean-Congo hemorrhagic fever (CCHF) virus is a tick-borne virus of the Nairovirus genus
1944: First characterized in Crimea during an outbreak among agricultural workers and subsequently called the Crimean hemorrhagic fever
1969: virus re-recognized as a cause of illness in the Congo
Found in Eastern Europe, northern China, central Asia, India, the Middle East, the Mediterranean, and Africa
Sudden onset of headache, high fever, back, joint & stomach pain, and vomiting
As illness proceeds, can lead to bleeding beginning on the fourth day of illness and lasting for two weeks
Diagnosed via ELISA and RT-PCR
Supportive treatment for fluid balance, also responds to ribavirin

Image from Centers for Disease Control Website

Acute fever caused by Rift Valley Fever virus
Primarily infects domesticated animals but can also infect humans
Virus is of the Phlebovirus genus
Transmitted by mosquitoes (several species); outbreaks often occur during years of heavy rainfall and localized flooding
Generally found in eastern and southern Africa, where sheep and cattle are raised
Can lead to significant economic loss due to sick livestock
Spillovers into human populations have occurred, notably in 1977 in Egypt and 1987 in the Senegal River area
Diagnosed via ELISA and PCR during early phases of illness
Most human cases are mild and self-limiting
Most common complication for humans is an inflammation fo the retina, leading to 1-10% of patients to have permanent vision loss.
Incubation period of 2-6 days with fever, weakness, back pain, and dizziness as the most common symptoms

Image from Centers for World Health Organization

Group of illnesses caused by hantaviruses, including Hantaan, Dobrava, Saaremaa, Seoul, and Puumala
Found around the world; each virus has a characteristic region
Eastern Asia: Hantaan virus
Europe: Puumala Virus
Balkans: Dobrava Virus
Worldwide: Seoul Virus
Central Europe & Scandinavia: Saaremaa Virus
Transmitted by rodents (natural reservoir); roden control is primary prevention
Typical incubation period of 1 to 2 weeks
Initial symptoms include sudden headaches, back and abdominal pain, fever, chills, nausea, and blurred vision
Later symptoms include low blood pressure, vascular leakage, and acute kidney failure, leading to fluid overload
Diagnosed via hantavirus antigen in tissue via immunohistochemical staining
Can be fatal

Image of Hantavirus from Virology Online

"Virus Taxonomy: 2014 Release." International Committee on Taxonomy of Viruses. http://ictvonline.org/virusTaxonomy.as
Fields Virology, 6th Edition, Chapter 42: Bunyaviridae
"Chapter 56: Bunyaviruses." Medical Microbiology. 4th edition. http://www.ncbi.nlm.nih.gov/books/NBK8004/
"Bunyaviridae." Viral Hemorrhagic Fevers (VHFs). Centers for Disease Control and Prevention. http://www.cdc.gov/vhf/virus-families/bunyaviridae.html
"Crimean-Congo Hemorrhagic Fever (CCHF)." Centers for Disease Control and Prevention. http://www.cdc.gov/vhf/crimean-congo/index.html
"Rift Valley Fever." Centers for Disease Control and Prevention. http://www.cdc.gov/vhf/rvf/index.html
"Hemorrhagic Fever with Renal Syndrome (HFRS)." Centers for Disease Control and Prevention. http://www.cdc.gov/hantavirus/hfrs/index.html