''Heartland bandavirus'', sometimes called Heartland virus (HRTV), is a tick-borne ''

phlebovirus ''Phlebovirus'' is one of twenty genera of the family ''Phenuiviridae'' in the order ''Bunyavirales''. The genus contains 66 species. It derives its name from Phlebotominae, the Vector (disease vector, vectors of member species ''Naples phlebovir ...

'' of the '' Bhanja virus'' serocomplex discovered in 2009. The

lone star tick ''Amblyomma americanum'', also known as the lone star tick, the northeastern water tick, or the turkey tick, or the "Cricker Tick", is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly ...

transmits the virus to people when feeding on blood. As of 2017, only five states in the

Central United States The Central United States is sometimes conceived as between the Eastern and Western as part of a three-region model, roughly coincident with the U.S. Census' definition of the Midwestern United States plus the western and central portions of ...

have reported 20 human infections, namely Arkansas, Indiana, Missouri, Oklahoma, and Tennessee; symptoms resemble those of two other tick-borne infections

ehrlichiosis Ehrlichiosis is a Tick-borne disease, tick-borne bacterial infection, caused by bacteria of the family Anaplasmataceae, genera ''Ehrlichia'' and ''Anaplasma''. These Obligate intracellular parasite, obligate intracellular bacteria infect and kill ...

and

anaplasmosis Anaplasmosis is a tick-borne disease affecting ruminants, dogs, and horses, and is caused by ''Anaplasma'' bacteria. Anaplasmosis is an infectious but not contagious disease. Anaplasmosis can be transmitted through mechanical and biological vector ...

. The reservoir host is unknown, but deer, raccoon, coyotes, and moose in 13 different states have

antibody titer Titer (American English) or titre (British English) is a way of expressing concentration. Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inherently only evaluates as positiv ...

s against the virus.

History

The ''Heartland virus'' (HRTV) was discovered in 2009 in northwestern

Missouri Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...

by Dr. Scott Folk of Heartland Regional Medical Center in

St. Joseph, Missouri St. Joseph is a city in and the county seat of Buchanan County, Missouri. Small parts of St. Joseph extend into Andrew County. Located on the Missouri River, it is the principal city of the St. Joseph Metropolitan Statistical Area, which includ ...

. The virus was first proven to infect humans in June 2009 when two farmers, living apart, presented with fever, fatigue, diarrhea,

thrombocytopenia Thrombocytopenia is a condition characterized by abnormally low levels of platelets, also known as thrombocytes, in the blood. It is the most common coagulation disorder among intensive care patients and is seen in a fifth of medical patients an ...

, and

leukopenia Leukopenia () is a decrease in the number of leukocytes (WBC). Found in the blood, they are the white blood cells, and are the body's primary defense against an infection. Thus the condition of leukopenia places individuals at increased risk of inf ...

. The

Lone Star Tick ''Amblyomma americanum'', also known as the lone star tick, the northeastern water tick, or the turkey tick, or the "Cricker Tick", is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly ...

transmits the virus to people when feeding on blood.

Classification

The ''Heartland virus'' is part of the ''

Bunyavirales ''Bunyavirales'' is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class ''Ellioviricetes''. The name ''Bunyavir ...

'' order of

viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

which contain 3 segments of −ssRNA. The genus of the virus is ''

Phlebovirus ''Phlebovirus'' is one of twenty genera of the family ''Phenuiviridae'' in the order ''Bunyavirales''. The genus contains 66 species. It derives its name from Phlebotominae, the Vector (disease vector, vectors of member species ''Naples phlebovir ...

'' and the species is the ''Heartland virus''.

Transmission

In 2013, researchers from the CDC and

Missouri Western State University Missouri Western State University is a public university in Saint Joseph, Missouri. As of 2019, it enrolled 5,413 students. History Missouri Western State University was founded in 1915 as a two-year institution called St. Joseph Junior College ...

first isolated the ''Heartland virus'' (HRTV) from the Lone Star Tick (''

Amblyomma americanum ''Amblyomma americanum'', also known as the lone star tick, the northeastern water tick, or the turkey tick, or the "Cricker Tick", is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly ...

''). As of 2013 work continued to identify the reservoir host, as HRTV has not been isolated from any wild or domestic animals though many white-tailed deer and raccoon from northwestern Missouri had antibodies to HRTV, suggesting that they may be hosts. In a 2015 retrospective study using convenience samples of different wild animal sera deer, raccoon, coyotes, and moose had antibodies against HRTV. They lived in thirteen states: Florida, Georgia, Illinois, Indiana, Kansas, Kentucky, Missouri, North Carolina, Tennessee, Texas, but also New Hampshire, Maine and Vermont. The infections could have occurred as early as 2003, based on the estimated ages of affected deer. Since the Lone Star tick does not occur in northern New England it is assumed that a second type of tick can carry HRTV.

Infection

Signs and symptoms

Signs and symptoms include fever in excess of 100.4 °F (38 °C), lethargy (weakness), headaches, muscle pain (

myalgia Myalgia (also called muscle pain and muscle ache in layman's terms) is the medical term for muscle pain. Myalgia is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another likel ...

), loss of appetite, nausea, diarrhea, weight loss, joint pain (

arthralgia Arthralgia (from Greek ''arthro-'', joint + ''-algos'', pain) literally means ''joint pain''. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication. According to MeSH, ...

), low white blood cell count (

) and easy bruising due to a low platelet count (

). Elevated liver

transaminases Transaminases or aminotransferases are enzymes that catalyze a transamination reaction between an amino acid and an α-keto acid. They are important in the synthesis of amino acids, which form proteins. Function and mechanism An amino acid co ...

may also be present.

Risk factors

All known human cases have been reported from five U.S. states: Arkansas, Indiana, Missouri, Oklahoma, and Tennessee. Most people infected were spending time outdoors in regions where ticks are

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

. Most infections are diagnosed between May and September. People usually report having been bitten by a tick within two weeks prior to seeking health care.

Diagnosis

Diagnosis is through the elimination of other causes of infectious diseases with related symptoms like

and

or if the patient fails to respond to treatment with the antibiotic

doxycycline Doxycycline is a broad-spectrum tetracycline class antibiotic used in the treatment of infections caused by bacteria and certain parasites. It is used to treat bacterial pneumonia, acne, chlamydia infections, Lyme disease, cholera, typhus, an ...

RT-PCR Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory technique combining reverse transcription of RNA into DNA (in this context called complementary DNA or cDNA) and amplification of specific DNA targets using polymerase ch ...

may then be used to detect viral ssRNA in the blood.

Antibody titer Titer (American English) or titre (British English) is a way of expressing concentration. Titer testing employs serial dilution to obtain approximate quantitative information from an analytical procedure that inherently only evaluates as positiv ...

s against the virus may also be used to indicate infection with the ''Heartland virus''.

Treatment

Treatment is non-specific. Antibiotics are not useful against viruses.

Intravenous fluid Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrie ...

administration and medications for the relief of pain are currently the best options.CDC Media relation
CDC Reports More Cases of Heartland Virus Disease
CDC press release, 27 March 2014

Prevention

When planning to spend time outdoors in areas where the virus is known or suspected to be harbored by ticks, it is recommended that one cover the body completely with long sleeves and pants, and to avoid bushy and wooded areas. Although ticks are not consistently repelled by DEET-containing repellents, insect repellents should still be applied to one's body and gear. It is recommended that one perform thorough tick checks after being outside, and to remove any tick immediately. If a tick is found, one should remove the tick by the head, preferably with a pair of fine-tipped tweezers. Squeezing the abdomen of a tick while it is attached can force viruses and bacteria into the wound, increasing the chance of infection. Crushing an unattached tick will also release bacteria and viruses from its abdomen, which may then be able to enter a wound or burrow through the skin.

Human cases

More than 20 human infections have been reported in the United States, but given the obscurity of the disease, the true number of cases is suspected to be substantially larger.

References

{{Taxonbar, from=Q70627232, from2=Q5692897 Phleboviruses Tick-borne diseases Unaccepted virus taxa