EID Journal: Novel Bunyavirus In Livestock - Minnesota

(Credit CDC)

 

 

# 7542

 

Bunyaviruses are an incredibly diverse family of negative stranded enveloped RNA viruses that are responsible for such dreaded diseases as Rift Valley Fever, Crimean - Congo Hemorrhagic Fever (CCHF), and Hantavirus.

 

While these viruses most commonly infect arthropods and rodents (and occasionally humans), curiously, one variety even infects plants - the (Tospovirsus) – and is responsible for tomato spotted wilt.

 

In the United States, probably the most common Bunyavirus infection reported is La Crosse (LAC) encephalitis, and less commonly Jamestown Canyon (JCV) and California encephalitis (CE). 

 

All three being mosquito vectored illnesses.

 

Over the past few years we’ve seen a new, often serious human infection emerge in Asia  - Severe Fever with Thrombocytopenia Syndrome (SFTS) - that produces a high fever, a low platelet count and and can lead to multiple organ failure.

 

SFTS first came to our attention in the spring and summer of 2009  after outbreaks were identified in China’s Hubei and Henan provinces.  While ticks were suspected as vectors, the pathogen behind this disease was not initially known.

 

In 2011, the NEJM published a study Fever with Thrombocytopenia Associated with a Novel Bunyavirus in China.  STFS has been associated with a 12% mortality rate in China.

 

Over the past year, we’ve seen reports of SFTS in Japan and Korea as well (see Japan Announces 4th SFTS Fatality,  Korean CDC On SFTS Cases).  Of note, we’ve also seen evidence of limited human-to-human transmission of this virus.

 

Person-to-person transmission of severe fever with thrombocytopenia syndrome virus.

Liu Y, Li Q, Hu W, Wu J, Wang Y, Mei L, Walker DH, Ren J, Wang Y, Yu XJ.

(Excerpt)

We concluded that SFTSV can be transmitted from person to person through contacting patient's blood.

 

Last year, in New Phlebovirus Discovered In Missouri we also learned of the discovery of another novel Bunyavirus – dubbed the Heartland Virus (HLV) - in two residents of Western Missouri. Last month CIDRAP NEWS reported that Researchers trace novel Heartland virus to Missouri ticks.

 

All of which serves as prelude to today’s report in the CDC’s EID Journal, where researchers in Minnesota conducted serological testing of domestic and captive farmed animals looking for evidence of SFTS and the Heartland virus.

 

What they found was 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 HLV and SFTF are antigenically cross reactive, the authors believe `the viruses detected in this region are most likely HLV or close relatives of HLV.’

 

The entire study is well worth reading, and is available at the link below.  I’ve excerpted the abstract and a small portion from the conclusion, as it speaks to the impact this discovery may have on public health.

 

Volume 19, Number 9—September 2013

Dispatch

Novel Bunyavirus in Domestic and Captive Farmed Animals, Minnesota, USA

Zheng Xing , Jeremy Schefers, Marc Schwabenlander, Yongjun Jiao, Mifang Liang, Xian Qi, Chuan Li, Sagar Goyal, Carol J. Cardona, Xiaodong Wu, Zerui Zhang, Dexin Li, James Collins, and Michael P. Murtaugh

Abstract

We tested blood samples from domestic and captive farmed animals in Minnesota, USA, to determine exposure to severe fever with thrombocytopenia syndrome virus and Heartland-like virus. We found antibodies against virus nucleoproteins in 10%–18% of samples from cattle, sheep, goats, deer, and elk in 24 Minnesota counties.

 

<SNIP>

Conclusion (EXCERPT)

Farmers, hunters, and persons with outdoor lifestyles may become infected when they are bitten by infected ticks. In addition, direct contact with secretions, body liquids, or feces from viremic animals would also put these persons and veterinarians at risk, if HLV- infected animals have substantial amounts of virus in blood and other tissues. The direct contact transmission of SFTSV has been reported in family clusters among persons with no history of tick bites, suggesting that person-to-person transmission may also occur (13–15).

 

Evidence that a novel phlebovirus infects domesticated and captive farmed animals as shown in this study validates the concern that an SFTSV- or HLV-like emerging pathogen could pose a serious public health threat in the United States. Epidemiologic studies with a broader scope need to be conducted to elucidate viral ecology, and effective measures must be adopted to control this virus before it spreads among humans.

 

 

 

Although most people think first of Lyme disease when they get a tick bite, The CDC lists a growing number of diseases carried by ticks in the United States, including: Anaplasmosis, Babesiosis , Ehrlichiosis, Lyme disease, Rickettsia parkeri Rickettsiosis, Rocky Mountain Spotted Fever (RMSF), STARI (Southern Tick-Associated Rash Illness), Tickborne relapsing fever (TBRF), Tularemia, and 364D Rickettsiosis.

We’ve discussed a number these in the past, including:

 

Referral: Maryn McKenna On Babesia And The Blood Supply

NEJM: Emergence Of A New Bacterial Cause Of Ehrlichiosis

tick . . . tick . . . tick . . .

Minnesota: Powassan Virus Fatality

 

Given the smorgasbord of  of diseases carried by ticks it makes sense to avoid their bites whenever possible.  This advice from the Minnesota Department of Health.

Japan Reports Two Additional SFTS Fatalities

 

Photo Credit Wikipedia

Tick Species Associated with SFTS in China

 

 

# 6933

 

Two weeks ago, in SFTS Fatality Reported In Japan, we learned of the first known case of SFTS (Severe Fever with thrombocytopenia syndrome) recorded in Japan, linked to a tickborne Bunyavirus virus recently discovered in China.

 

Photo Credit Wikipedia

 

Outbreaks of this syndrome were first identified in central China's Hubei and Henan provinces during the spring and summer of 2009.

 

In 2011, the NEJM carried a report: Fever with Thrombocytopenia Associated with a Novel Bunyavirus in China that linked the syndrome to a novel virus.

 

At that time, human-to-human transmission of the virus was not suspected, but that changed with the 2012 publication of an article in the journal Vector Borne Zoonotic Diseases called:

Person-to-person transmission of severe fever with thrombocytopenia syndrome virus.

Liu Y, Li Q, Hu W, Wu J, Wang Y, Mei L, Walker DH, Ren J, Wang Y, Yu XJ.

(Excerpt)

We concluded that SFTSV can be transmitted from person to person through contacting patient's blood.

 

Today, thanks to a tip from a reader in Japan, we learn that two more cases of SFTS have been identified in Japan.

 

From NHK World News.

 

Tick-transmitted virus killed 2 more last year

Feb. 13, 2013 - Updated 06:51 UTC (15:51 JST)

Japanese health authorities have confirmed 2 more deaths last year from a tick-transmitted virus in western Japan.

 

In January, the health ministry confirmed that a woman in Yamaguchi Prefecture died last autumn of severe fever with thrombocytopenia syndrome, or SFTS.

 

The death was the first confirmed in Japan from the infectious disease, which has a 12 percent fatality rate. The virus that causes SFTS was identified in China in 2011.

 

Japan's National Institute of Infectious Diseases says 2 more patients, both adult males in Ehime and Miyazaki prefectures, also died of SFTS last year.

 

Neither man had traveled abroad before falling ill.
The viruses detected in the patients were genetically similar to the one found in Yamaguchi Prefecture but not those in China.

 

Health officials believe the 2 men were infected with the virus from tick bites in Japan. The virus-carrying ticks live outdoors and are of a different type from those found in clothing and bed

 

And another report the Daily Mainichi.

 

2 more Japanese confirmed dead due to new viral infection

TOKYO (Kyodo) -- The health ministry said Wednesday two more Japanese had been confirmed dead due to a new viral infection transmitted by a mite bite, bringing the death toll to three in the country.

(Continue . . .)

 

 

This brings to three the number of cases reported in Japan, and they all occurred in people without recent travel history out of the country, and in three separate prefectures.

From Japan’s Ministry of Health we get the following (albeit awkwardly machine translated) statement:

 

Situation in the country confirmed thrombocytopenia syndrome in patients with severe febrile (SFTS)

Recently, "syndrome thrombocytopenia febrile severe (Severe Fever with Thrombocytopenia Syndrome: SFTS)" disease tickborne new response to the fact that cases have been confirmed for the first time in the country, with respect to medical institutions, we have examined the patient similar If you provide information that has been requested through the local government cooperation (Annex 1).

 

Thing out of the case then, written by a medical institution, (died last fall either. male adults in Miyazaki Prefecture and adult men, Ehime Prefecture. no history of travel abroad these days) two cases were SFTS for infection National Since the disease is confirmed by laboratory tests, to local governments across the country that I have provided information effect (Annex 2).

 

Continue to conduct research and gather information about the disease, in the Ministry of Health, Labour and Welfare, we will take appropriate action.

SFTS Fatality Reported In Japan

Photo Credit Wikipedia

# 6899

 

 

Having recently read David Quammen’s terrific book on emerging infectious diseases called `Spillover’ (see EID Book Review – Spillover), I may be hyper-sensitized to any odd reports of newly emerging pathogens.

 

Nevertheless, this next story – which involves a recently discovered virus showing up in a new country  –  is unusual enough to merit mention.

 

Today the Mainichi is reporting that a Japanese adult – without recent travel history outside of the country – died last fall from a recently discovered viral infection called SFTS (Severe Fever with thrombocytopenia syndrome) that until now, has only been seen in China.

 

SFTS – linked to a recently discovered Bunyavirus - is believed to be transmitted primarily by ticks. Outbreaks were first identified in central China's Hubei and Henan provinces during the spring and summer of 2009.

 

We got our first real look at this syndrome from the NEJM in 2011 (see Fever with Thrombocytopenia Associated with a Novel Bunyavirus in China).  At that time, they stated `There was no epidemiologic evidence of human-to-human transmission of the virus.’

For more details on that NEJM report, I would invite you to read Lisa Schnirring’s excellent summary for CIDRAP NEWS  (Chinese researchers link febrile disease to new virus).

 

Since then, in February of 2012, the journal Vector Borne Zoonotic Diseases carried this game-changing report:

 

Person-to-person transmission of severe fever with thrombocytopenia syndrome virus.

 

Liu Y, Li Q, Hu W, Wu J, Wang Y, Mei L, Walker DH, Ren J, Wang Y, Yu XJ.

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a newly discovered bunyavirus, SFTS virus (SFTSV), and causes high fatality (12% on average and as high as 30%). The objective of this study was to determine whether SFTSV could be transmitted from person to person.

 

We analyzed sera of 13 patients from two clusters of unknown infectious diseases that occurred between September and November of 2006 in Anhui Province of China for SFTSV antibody by indirect immunofluorescence assay and for SFTSV RNA by RT-PCR. We found that all patients (n=14) had typical clinical symptoms of SFTS including fever, thrombocytopenia, and leukopenia and all secondary patients in both clusters got sick at 6-13 days after contacting or exposing to blood of index patients.

 

We demonstrated that all patients in cluster 1 including the index patient and nine secondary patients and all three secondary patients in cluster 2 had seroconversion or fourfold increases in antibody titer to SFTSV and/or by RT-PCR amplification of SFTSV RNA from the acute serum. The index patient in cluster 2 was not analyzed because of lack of serum. No person who contacted the index patient during the same period, but were not exposed to the index patient blood, had got illness.

 

We concluded that SFTSV can be transmitted from person to person through contacting patient's blood.

 

The question now is how did an adult male in Japan contract this never-reported-before-in-Japan virus? 

 

One might surmise that he came in contact with the blood of an infected individual who had recently visited China . . .  but today’s report states that:

 

Genetic studies show the virus that killed the Japanese occurred in Japan and did not come from China, the ministry said.

 

Which if correct, creates a bit of an epidemiological puzzle for public health experts to investigate.

 

Note: A h/t to Makoto on Twitter for the link.