Lone Star Tick - Credit CDC MMWR
# 8408
In August of 2012, in a New Phlebovirus Discovered In Missouri, I wrote about the CDC’s announcement of a new tick-borne virus detected in two Missouri farmers – living 60 miles apart, and with no epidemiological links - that was dubbed `The Heartland Virus’ (HLV) - named after the Heartland Regional Medical Center in St. Joseph, Mo which alerted the CDC back in 2009 about these cases
A 2012 NEJM report (A New Phlebovirus Associated with Severe Febrile Illness in Missouri), described the process that led to the identification of this novel virus:
Electron microscopy revealed viruses consistent with members of the Bunyaviridae family. Next-generation sequencing and phylogenetic analysis identified the viruses as novel members of the phlebovirus genus.
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This novel virus (which we called the Heartland virus) is a distinct member of the phlebovirus genus and is most closely related to tickborne phleboviruses, notably the recently isolated SFTSV
Phleboviruses are part of the family Bunyaviridae - which includes such nasties as Crimean-Congo hemorrhagic fever, Hantaviruses, and Rift Valley Fever. Bunyaviruses - are mostly spread via arthropod vectors (ticks, mosquitoes & sand flies), with the exception of Hantaviruses (see Hantaviruses Revisited), which are spread via the feces and urine of rodents.
This newly described `Heartland virus’ is genetically similar to another tickborne disease identified in China in 2011 called the SFTS virus (see EID Journal dispatch Severe Fever with Thrombocytopenia Syndrome Virus, Shandong Province, China Jun 2012).
Since then we’ve seen reports of SFTS in Japan and Korea as well (see Japan Announces 4th SFTS Fatality, Korean CDC On SFTS Cases).
And in September of 2013, we saw a report in the CDC’s EID Journal (Novel Bunyavirus in Domestic and Captive Farmed Animals, Minnesota, USA), where researchers found an unexpectedly high prevalence (10%-18%) of antibodies (using an ELSIA reagent kit developed by China’s CDC) to SFTS in the cattle, goats, sheep, and elk they tested.
Since the Heartland Virus (HLV) and SFTF are antigenically cross reactive, the authors believed `the viruses detected in this region are most likely HLV or close relatives of HLV.’
Given the geographical separation of the first two cases in Missouri, and the detection of HLV-like antibodies in farmed animals as far away as Minnesota, one cannot be too surprised to learn that additional human cases of HLV (5 in Missouri, 1 in Tennessee) have now been identified, as is reported today by the CDC’s MMWR.
Notes from the Field: Heartland Virus Disease — United States, 2012–2013
March 28, 2014 / 63(12);270-271
Daniel M. Pastula, MD1, George Turabelidze, MD2, Karen F. Yates, MS2, Timothy F. Jones, MD3, Amy J. Lambert, PhD4, Amanda J. Panella, MPH4, Olga I. Kosoy, MA4, Jason O. Velez4, Marc Fischer, MD4, J. Erin Staples, MD4 (Author affiliations at end of text)
Heartland virus is a newly identified phlebovirus that was first isolated from two northwestern Missouri farmers hospitalized with fever, leukopenia, and thrombocytopenia in 2009 (1). Based on the patients' clinical findings and their reported exposures, the virus was suspected to be transmitted by ticks. After this discovery, CDC worked with state and local partners to define the ecology and modes of transmission of Heartland virus, develop diagnostic assays, and identify additional cases to describe the epidemiology and clinical disease. From this work, it was learned that Heartland virus is found in the Lone Star tick (Amblyomma americanum) (Figure) (2). Six additional cases of Heartland virus disease were identified during 2012–2013; four of those patients were hospitalized, including one with comorbidities who died.
The CDC’s emailed press release summarizes the cases:
Ongoing investigations have yielded six more cases of Heartland virus disease, bringing to eight the total number of known cases. All of the six case-patients were white men over the age of 50. Their symptoms started in May to September and included fever, fatigue, loss of appetite, headache, nausea, or muscle pain. Four of the six new cases were hospitalized. One patient, who suffered from other health conditions, died. It is not known if Heartland virus was the cause of death or how much it contributed to his death. Five of the six new cases reported tick bites in the days or weeks before they fell ill.
Nearly all of the newly reported cases were discovered through a study conducted by the Missouri Department of Health and Senior Services and CDC who are actively searching for human cases at six Missouri hospitals.
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CDC studies to date have shown Heartland virus is carried by Lone Star ticks, which are primarily found in the southeastern and eastern United States. Additional studies seek to confirm whether ticks can spread the virus to people and to learn what other insects or animals may be involved in the transmission cycle. CDC is also looking for Heartland virus in other parts of the country to understand how widely it may be distributed.
The CDC’s Heartland Virus FAQ (updated yesterday, March 26th), provides the following advice regarding HLV.
How can people reduce the chance of getting infected with Heartland virus?
There is no vaccine or drug to prevent or treat the disease. Preventing bites from ticks and mosquitoes may prevent this and other infections.
- Use insect repellents
- Wear long sleeves and pants
- Avoid bushy and wooded areas
- Perform thorough tick checks after spending time outdoors
Additional information on reducing exposure to ticks is available on the CDC Ticks website.
How do I know if I have been infected with Heartland virus?
Currently, no tests are routinely available to tell if a person is infected with Heartland virus. Tests that will help a doctor diagnose Heartland virus infection are being developed. Consult your healthcare provider if you have any symptoms that concern you.
What is the treatment for Heartland virus disease?
There is no specific treatment for Heartland virus disease. Antibiotics are not effective against viruses. Supportive therapy can treat some symptoms. Some patients may need to be hospitalized for intravenous fluids, and treatment for pain or fever.
What should I do if I think someone might be infected with Heartland virus?
Consult your healthcare provider for proper diagnosis if you have any symptoms that concern you.
