Bourbon virus | |
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Electron micrograph of the spherical form of Bourbon virus (scale bar: 100 nm) | |
Virus classification ![]() | |
(unranked): | Virus |
Realm: | Riboviria |
Kingdom: | Orthornavirae |
Phylum: | Negarnaviricota |
Class: | Insthoviricetes |
Order: | Articulavirales |
Family: | Orthomyxoviridae |
Genus: | Thogotovirus |
Virus: | Bourbon virus |
Bourbon virus is an RNA virus in the genus Thogotovirus of the family Orthomyxoviridae , which is similar to Dhori virus and Batken virus. It was first identified in 2014 in a man from Bourbon County, Kansas, United States, who died after being bitten by ticks. The case is the eighth report of human disease associated with a thogotovirus globally, and the first in the Western hemisphere. As of May 2015, a case was discovered in Stillwater, Oklahoma (the patient fully recovered), and relatively little is known about the virus. No specific treatment or vaccine is available. The virus is suspected to be transmitted by ticks or insects, and avoidance of bites is recommended to reduce risk of infection. In June 2017 a 58-year-old female Missouri State Park employee died from an infection of the Bourbon virus after it had been misdiagnosed for a significant period of time. [1]
The virus was discovered in 2014 by Olga Kosoy, Amy Lambert and colleagues from the Centers for Disease Control and Prevention (CDC) in Fort Collins, Colorado, in a sample of blood from the case patient. [2] [3] Tests had previously ruled out a wide range of tick-borne diseases including anaplasmosis, babesiosis, ehrlichiosis, Q fever, Rocky Mountain spotted fever and tularemia. During tests for Heartland virus, a recently discovered Phlebovirus known to be transmitted by ticks, prominent plaques, or areas where the cells were affected by virus infection, were observed on one-cell-thick cultures of African green monkey kidney cells. The plaques did not resemble the effects of Heartland virus, and the researchers hypothesized that they were the work of another virus. Recently developed "next-generation" sequencing techniques were employed to find novel viral RNA sequences in cell culture supernatants, similar to viruses of the genus Thogotovirus, family Orthomyxoviridae . Lambert, who worked on the sequencing, explained that these "state-of-the-art" techniques could be used to identify pathogens that older technologies could not detect. [3]
Next, real-time reverse transcription–polymerase chain reaction was used to confirm that this novel virus originated in the patient's blood sample. [2] Finally, examining supernatants from the cell cultures under the electron microscope revealed virus particles of different shapes, including filaments and spheres. The virus was named "Bourbon virus" for the county in which it originated. [4] [5]
Bourbon virus is a type of thogotovirus, which is in the RNA virus family Orthomyxoviridae. The virus particles show different morphologies, including filamentous and roughly spherical forms, and have projections from the surface. The spherical virions have a range of diameters, with broadly 100–130 nm being common. Virus was present at high levels in the extracellular space, with occasional particles being observed in the process of endocytosis. Like other members of the Orthomyxoviridae, the Bourbon virus genome is single-stranded, negative-sense RNA, which is segmented, or divided into a number of separate pieces. It has at least six segments. Bourbon virus is most similar in RNA sequence to Dhori virus and the closely related Batken virus, both members of the genus Thogotovirus, but has diverged substantially from these viruses. Dhori and Batken viruses have only been reported in the Eastern hemisphere. [2]
The Bourbon virus was first identified in a previously healthy man aged more than 50 years from Bourbon County, Kansas, United States, who worked as a farmer. [2] [5] [6] [7] He died in June 2014. [4] Dana Hawkinson from the University of Kansas Hospital, where the patient was treated, has speculated that the virus had been previously present undetected. [4] [7] There have been five confirmed cases since 2014. [8] [9] The CDC is developing investigational diagnostic tests for Bourbon virus infection; [5] [6] as of December 2014, CDC and the Kansas Department of Health and Environment were planning to test blood samples from people in Kansas who have recently experienced similar unexplained symptoms. [5] It is unknown whether the virus can infect non-human animals, and studies are ongoing to investigate this. [6]
The case patient reported multiple tick bites, including a blood-filled tick in the shoulder area that was observed a few days before the onset of symptoms. [2] Based on the history of the case patient, the virus is considered to be possibly tick-borne, but this has not been proven. Most thogotoviruses are transmitted solely by ticks, but the similar Batken virus has also been isolated from mosquitoes. [2] [10] Studies to establish the prevalence of Bourbon virus in tick and insect populations were planned in December 2014. [5] [7]
The patient had high fever, headache, decreased appetite, muscle aches, joint pain, fatigue, malaise, nausea, vomiting, diarrhea and a maculopapular rash on the abdomen, chest and back. Late in the course of the illness he experienced shortness of breath, which developed into acute respiratory distress syndrome. He died from multiple organ failure 11 days after the earliest symptoms. [2] [5] [6] Laboratory abnormalities observed included a decrease in the patient's white cell and platelet counts, considered to be caused by bone marrow suppression, and an increase in liver enzyme levels. [2] [6] These symptoms and alterations in blood cells are similar to those seen with tick-borne illnesses including ehrlichiosis and disease caused by the Heartland virus. [5]
The degree, if any, to which the Bourbon virus contributed to the individual's illness and death remains unknown as of February 2015, as does whether these symptoms and laboratory abnormalities represent the typical course of infection with Bourbon virus. [2] [5] Hawkinson has speculated that there have been previous undiagnosed cases with milder symptoms from which the infected patients recovered. [7]
Thogotoviruses rarely cause disease in humans. The case in Bourbon County is only the eighth report of human disease associated with a thogotovirus globally. [2] Thogoto virus caused disease in two people from Nigeria, one of whom died; Dhori virus caused disease in five laboratory workers infected accidentally. [2] [11] [12] Although another member of the genus Thogotovirus, Aransas Bay virus, has been found in seabird-associated ticks in the United States; [2] [13] this is the first reported case of human disease apparently associated with a thogotovirus in the Western hemisphere. [3] [14]
No routine diagnostic test is yet available. [6] There is currently no specific treatment or vaccine for the virus; [5] [6] supportive therapy is recommended. [6] On the assumption that the virus is transmitted by a tick or insect, the main prevention method recommended is the avoidance of tick and insect bites. [6] In mice models, Favipiravir has been shown to be beneficial both therapeutically and prophylactically. [15]
Colorado tick fever (CTF) is a viral infection (Coltivirus) transmitted from the bite of an infected Rocky Mountain wood tick (Dermacentor andersoni). It should not be confused with the bacterial tick-borne infection, Rocky Mountain spotted fever. Colorado tick fever is probably the same disease that American pioneers referred to as "mountain fever".
Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents transmitted by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa. The economic impact of tick-borne diseases is considered to be substantial in humans, and tick-borne diseases are estimated to affect ~80 % of cattle worldwide. Most of these pathogens require passage through vertebrate hosts as part of their life cycle. Tick-borne infections in humans, farm animals, and companion animals are primarily associated with wildlife animal reservoirs. Many tick-borne infections in humans involve a complex cycle between wildlife animal reservoirs and tick vectors. The survival and transmission of these tick-borne viruses are closely linked to their interactions with tick vectors and host cells. These viruses are classified into different families, including Asfarviridae, Reoviridae, Rhabdoviridae, Orthomyxoviridae, Bunyaviridae, and Flaviviridae.
Viral hemorrhagic fevers (VHFs) are a diverse group of animal and human illnesses. VHFs may be caused by five distinct families of RNA viruses: the families Filoviridae, Flaviviridae, Rhabdoviridae, and several member families of the Bunyavirales order such as Arenaviridae, and Hantaviridae. All types of VHF are characterized by fever and bleeding disorders and all can progress to high fever, shock and death in many cases. Some of the VHF agents cause relatively mild illnesses, such as the Scandinavian nephropathia epidemica, while others, such as Ebola virus, can cause severe, life-threatening disease.
Tick-borne encephalitis (TBE) is a viral infectious disease involving the central nervous system. The disease most often manifests as meningitis, encephalitis or meningoencephalitis. Myelitis and spinal paralysis also occurs. In about one third of cases sequelae, predominantly cognitive dysfunction, persist for a year or more.
Tick-borne encephalitis virus (TBEV) is a positive-strand RNA virus associated with tick-borne encephalitis in the genus Flavivirus.
Kyasanur forest disease (KFD) is a tick-borne viral haemorrhagic fever endemic to South-western part of India. The disease is caused by a virus belonging to the family Flaviviridae. KFDV is transmitted to humans through the bite of infected hard ticks which act as a reservoir of KFDV.
Crimean–Congo hemorrhagic fever (CCHF) is a viral disease. Symptoms of CCHF may include fever, muscle pains, headache, vomiting, diarrhea, and bleeding into the skin. Onset of symptoms is less than two weeks following exposure. Complications may include liver failure. Survivors generally recover around two weeks after onset.
Thogotovirus is a genus of enveloped RNA viruses, one of seven genera in the virus family Orthomyxoviridae. Their single-stranded, negative-sense RNA genome has six or seven segments. Thogotoviruses are distinguished from most other orthomyxoviruses by being arboviruses – viruses that are transmitted by arthropods, in this case usually ticks. Thogotoviruses can replicate in both tick cells and vertebrate cells; one subtype has also been isolated from mosquitoes. A consequence of being transmitted by blood-sucking vectors is that the virus must spread systemically in the vertebrate host – unlike influenza viruses, which are transmitted by respiratory droplets and are usually confined to the respiratory system.
Seoul orthohantavirus (SEOV) is a member of the genus Orthohantavirus of rodent-borne viruses, and is one of the four hantaviruses that are known to cause Hantavirus hemorrhagic fever with renal syndrome (HFRS). It is an Old World hantavirus; a negative sense, single-stranded, tri-segmented RNA virus.
Andes orthohantavirus (ANDV), a species of Orthohantavirus, is a major causative agent of hantavirus cardiopulmonary syndrome (HCPS) and hantavirus pulmonary syndrome (HPS) in South America. It is named for the Andes mountains of Chile and Argentina, where it was first discovered. Originating in the reservoir of rodents, Andes orthohantavirus is easily transmitted to humans who come into contact with infected rodents or their fecal droppings. However, infected rodents do not appear ill, so there is no readily apparent indicator to determine whether the rodent is infected or not. Additionally, Andes orthohantavirus, specifically, is the only hantavirus that can be spread by human to human contact via bodily fluids or long-term contact from one infected individual to a healthy person.
Powassan virus (POWV) is a Flavivirus transmitted by ticks, found in North America and in the Russian Far East. It is named after the town of Powassan, Ontario, where it was identified in a young boy who eventually died from it. It can cause encephalitis, inflammation of the brain. No approved vaccine or antiviral drug exists. Prevention of tick bites is the best precaution.
Amblyomma americanum, also known as the lone star tick, the northeastern water tick, or the turkey tick, is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly goes unnoticed, remaining attached to its host for as long as seven days until it is fully engorged with blood. It is a member of the phylum Arthropoda, class Arachnida. The adult lone star tick is sexually dimorphic, named for a silvery-white, star-shaped spot or "lone star" present near the center of the posterior portion of the adult female shield (scutum); adult males conversely have varied white streaks or spots around the margins of their shields.
Dhori virus (DHOV) is a species of the genus Thogotovirus and a member of the family Orthomyxoviridae. Its host is most commonly Ixodidae ticks but can also be other species of ticks, mosquitoes, and mammals. DHOV is lethal to mice, leads to high rates of miscarriages in sheep and goats, and causes systemic pathologic changes similar to those reported in humans with virulent influenza A (H5N1) virus infection.
Ehrlichia chaffeensis is an obligate intracellular, Gram-negative species of Rickettsiales bacteria. It is a zoonotic pathogen transmitted to humans by the lone star tick. It is the causative agent of human monocytic ehrlichiosis.
Human granulocytic anaplasmosis (HGA) is a tick-borne, infectious disease caused by Anaplasma phagocytophilum, an obligate intracellular bacterium that is typically transmitted to humans by ticks of the Ixodes ricinus species complex, including Ixodes scapularis and Ixodes pacificus in North America. These ticks also transmit Lyme disease and other tick-borne diseases.
Human monocytotropic ehrlichiosis is a form of ehrlichiosis associated with Ehrlichia chaffeensis. This bacterium is an obligate intracellular pathogen affecting monocytes and macrophages.
Ticks are insects known for attaching to and sucking blood from land-dwelling animals. Ticks fall under the category of 'arthropod', and while they are often thought of in the context of disease transmission, they are also known to cause direct harm to hosts through bites, toxin release, and infestation. Infestation can cause symptoms ranging from mild to severe and may even cause death. Hosts can include any number of vertebrates, though humans and livestock are more likely to be the interest of researchers.
Heartland bandavirus, sometimes called Heartland virus (HRTV), is a tick-borne phlebovirus of the Bhanja virus serocomplex discovered in 2009. The lone star tick transmits the virus to people when feeding on blood. As of 2017, only five states in the Central United States have reported 20 human infections, namely Arkansas, Indiana, Missouri, Oklahoma, and Tennessee; symptoms resemble those of two other tick-borne infections ehrlichiosis and anaplasmosis. The reservoir host is unknown, but deer, raccoon, coyotes, and moose in 13 different states have antibody titers against the virus. By 2023 over 50 human infections were reported in at least eleven states.
Quaranjavirus is a genus of enveloped RNA viruses, one of seven genera in the virus family Orthomyxoviridae. The genome is single-stranded, negative-sense segmented RNA, generally with six segments. The genus contains two species: Johnston Atoll virus and Quaranfil virus; it has been proposed to contain species or strains including Cygnet River virus, Lake Chad virus, Tyulek virus and Wellfleet Bay virus. Quaranjaviruses predominantly infect arthropods and birds; As of March 2015, Quaranfil quaranjavirus is the only member of the genus to have been shown to infect humans. The Quaranfil and Johnston Atoll viruses are transmitted between vertebrates by ticks, resembling members of Thogotovirus, another genus of Orthomyxoviridae.
Royal Farm virus, previously known as Karshi virus, was not viewed as pathogenic or harmful to humans. Although infected people suffer with fever-like symptoms, some people in Uzbekistan have reported with severe disease such as encephalitis and other large outbreaks of fever illness connected infection with the virus.