Ecology, transmission, and diagnosis of mosquito-borne Tahyna virus

Published

2 years ago

May 4, 2023

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By Tarun Sai Lomte May 4 2023 Reviewed by Lily Ramsey, LLM

A recent study published in the Zoonoses and Public Health Journal summarized the current knowledge on the Tahyna virus (TAHV).

Study: Ťahyňa virus—A widespread, but neglected mosquito-borne virus in Europe. Image Credit: xpixel/Shutterstock.com Background

TAHV is a human pathogen of the California serogroup (CSG) orthobunyaviruses. It is a spherical enveloped virus around 100 nm in diameter, with three segments of negative-sense single-stranded RNA as the genome.

The genome is about 13 kb in size, and the segments are labeled as small (S), medium (M), and large (L). The S segment encodes a non-structural protein and the nucleocapsid.

The M segment encodes a polyprotein cleaved into two glycoproteins and a non-structural protein, whereas the L segment encodes an RNA-dependent RNA polymerase. The bunyaviral non-structural proteins might be pathogenic factors in vertebrates. TAHV was the first pathogenic arbovirus isolated from mosquitos in Europe.

TAHV transmission occurs via endemic mosquitos, with mammals as vertebrate hosts. Research attention shifted toward the medical significance of the virus when it was isolated from sick/hospitalized children.

Valtice fever, caused by TAHV, manifests as a febrile summer illness with laryngitis, nausea, and atypical pneumonia, particularly in children.

Acute neurologic symptoms also occur but in relatively fewer cases. There are no reports of fatalities. Given the widespread distribution of TAHV in Central Europe, it should be studied from a public health perspective.

The present study’s authors discussed the available knowledge on TAHV history, geographic distribution, transmission, diagnosis, and clinical manifestations. Ecology, hosts, and vectors of TAHV

TAHV transmission in endemic regions occurs in deciduous/mixed woodland forests with trees withstanding floods. TAHV outbreaks have been mainly recorded in southern Moravia and southern/eastern Slovakia. Related StoriesStudy indicates that targeted interventions strengthening HIV antiretroviral therapy initiation are criticalWhat is the risk for symptomatic H5N1 virus infection in humans?Study suggests the zoonotic-like avian H3N8 virus has limited efficiency for human-to-human transmission and is unlikely to cause severe disease in humans

Serologic investigations report increased TAHV exposure in flooded areas and regions adjacent to rivers, where floodplain mosquitos exist. TAHV was also detected in several biotopes in Asia.

Studies indicate that European hares are the likely amplifying hosts of TAHV. Experimental studies showed that Central Europe-endemic mammalian species develop viremia and TAHV-specific antibodies. However, only hares and rabbits have been established as competent hosts. Although infection in primates caused viremia and induced antibodies, the animals lacked clinical symptoms.

One study observed a febrile period of up to four days, reduced motility, and weakness in chimpanzees infected subcutaneously. Serosurveys detected TAHV-reactive antibodies in red deer, wild boars, fallow deer, mouflons, red deer, horses, cattle, wild rodents, European brown bears, and domestic sheep.

TAHV has been isolated from several mosquito species, including Aedes vexans, A. cinereus, and A. caspius, with many studies implicating A. vexans as the primary vector. Disease and diagnosis

Valtice fever may manifest from mild febrile illness to aseptic meningoencephalitis. TAHV infection causes symptoms similar to those caused by other CSG orthobunyaviruses, such as California encephalitis and La Crosse viruses. The main symptoms include severe headage, accompanied by nausea and dizziness.

Other symptoms include atypical pneumonia, anorexia, conjunctivitis, myalgia, laryngitis, and gastrointestinal symptoms typical of encephalitic orthobunyaviruses.

Only a small proportion of infected individuals may develop pleocytosis or severe meningitis. Serosurveys in endemic regions of Czechoslovakia revealed a high seroprevalence of up to 70%.

TAHV was isolated for the first time from a human with a natural infection in 1972. Subsequently, it was isolated from hospitalized children with acute fever. TAHV seropositivity has been documented in several European countries like Hungary, Austria, Yugoslavia, Croatia, Albania, and Russia. China, Uzbekistan, and Tajikistan have also reported TAHV infections.

Serum immunoglobulin M (IgM) detection is the basis of TAHV diagnosis, with virus neutralization tests accepted as the gold standard. TAHV infection could be diagnosed using a reverse-transcription polymerase chain reaction (RT-PCR) test.

Although TAHV infections are prevalent, disease incidence is often underreported due to the lack of diagnostic tests. As such, TAHV infections remain underdiagnosed in several countries. Concluding remarks

In summary, while TAHV remains endemic to Central Europe, with a larger geographic distribution, there is limited data on fundamental ecological and virological aspects.

Mosquito surveillance should also involve screening for TAHV. Although TAHV causes a relatively mild illness, the manifestation of neurologic symptoms cannot be overlooked.

Above all, high temperatures and increased flooding events in summer could lead to TAHV transmission; therefore, control strategies and serologic surveys should be implemented in regions where TAHV or its vectors exist. Journal reference:

Mravcová, K., Camp, J.V., Hubálek, Z., Šikutová, S., Vaux, A.G.C., Medlock, J.M. & Rudolf, I. (2023) Ťahyňa virus—A widespread, but neglected mosquito‐borne virus in Europe. Zoonoses and Public Health. doi: 10.1111/zph.13042 https://onlinelibrary.wiley.com/doi/10.1111/zph.13042

Business

Britain’s winter blackout risk the lowest in six years – but ‘tight’ days expected

Published

3 hours ago

October 9, 2025

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Britain's winter blackout risk the lowest in six years - but 'tight' days expected

Britain is at the lowest risk of a winter power blackout than at any point in the last six years, the national electricity grid operator has said.

Not since the pre-pandemic winter of 2019-2020 has the risk been so low, the National Energy System Operator (NESO) said.

It’s thanks to increased battery capacity to store and deploy excess power from windfarms, and a new subsea electricity cable to Ireland that came on stream in April.

The margins between expected demand and supply are now roughly three gas power stations greater than last year, the NESO said.

It also comes as Britain and the world reached new records for green power.

For the first time, renewable energy produced more of the world’s electricity than coal in the first half of 2025, while in Britain, a record 54.5% of power came from renewables like solar and wind energy in the three months to June.

More renewable power can mean lower bills, as there’s less reliance on volatile oil and gas markets, which have remained elevated after the invasion of Ukraine and the Western attempt to wean off Russian fossil fuels.

“Renewables are lowering wholesale electricity prices by up to a quarter”, said Jess Ralston, an energy analyst at the Energy and Climate Intelligence Unit (ECIU) thinktank.

In a recent winter, British coal plants were fired up to meet capacity constraints when cold weather increased demand, but still weather conditions meant lower supply, as the wind didn’t blow.

Those plants have since been decommissioned.

But it may not be all plain sailing…

There will, however, be some “tight” days, the NESO said.

On such occasions, the NESO will tell electricity suppliers to up their output.

The times Britain is most likely to experience supply constraints are in early December or mid-January, the grid operator said.

The NESO had been owned by National Grid, a public company listed on the New York Stock Exchange, but was acquired by the government for £630m in 2023.

Business

Man Utd and chemicals boss warns of ‘moment of reckoning’ for his industry

Published

3 hours ago

October 9, 2025

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Man Utd and chemicals boss warns of 'moment of reckoning' for his industry

Sir Jim Ratcliffe, the co-owner of Manchester United and head of Ineos, one of Europe’s largest chemical producers, has staged an “11th-hour intervention” in an effort to “save” the chemical industry.

Sir Jim has called on European legislators to reduce price pressures on chemical businesses, or there “won’t be a chemical industry left to save”.

“There’s, in my view, not a great deal of time left before we see a catastrophic decline in the chemical industry in Europe”, he said.

The “biggest problem” facing businesses is gas and electricity costs, with the EU needing to be “more reactive” on tariffs to protect competition, Sir Jim added.

Prices should be eased on chemical companies by reducing taxes, regulatory burdens, and bringing back free polluting permits, the Ineos chairman and chief executive said.

It comes as his company, Europe’s biggest producer of some chemicals and one of the world’s largest chemical firms, announced the loss of 60 jobs at its acetyls factory in Hull earlier this week.

Cheap imports from China were said to be behind the closure, as international competition facing lower costs has hit the sector.

What could happen?

Now is a “moment of reckoning” for Europe’s chemicals industry, which is “at a tipping point and can only be saved through urgent action”, Sir Jim said.

European chemical sector output declined significantly due to reduced price competitiveness from high energy and regulatory costs, according to research funded by Ineos and carried out by economic advisory firm Oxford Economics.

The report said the continent’s policymakers face a “critical” decision between acting now to safeguard “this vital strategic industry or risk its irreversible decline”.

As many as 1.2 million people are directly employed by chemical businesses, with millions more supported in the supply chain and through staff spending wages, the Oxford Economics report read.

Average investment by European chemical firms was half that of US counterparts (1.5%, compared to 3%), a trend which is projected to continue, the report added.

Sports

Jays knock out Yankees, reach 1st ALCS since ’16

Published

6 hours ago

October 9, 2025

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Jays knock out Yankees, reach 1st ALCS since '16

Associated Press

Oct 8, 2025, 10:39 PM ET

NEW YORK — Vladimir Guerrero Jr. and George Springer each drove in a run, and eight Toronto pitchers shut down the New York Yankees in a 5-2 victory Wednesday night that sent the Blue Jays to the American League Championship Series for the first time in nine years.

Nathan Lukes provided a two-run single and Addison Barger had three of Toronto’s 12 hits as the pesky Blue Jays, fouling off tough pitches and consistently putting the ball in play, bounced right back after blowing a five-run lead in Tuesday night’s loss at Yankee Stadium.

AL East champion Toronto took the best-of-five Division Series 3-1 and will host Game 1 in the best-of-seven ALCS on Sunday against the Detroit Tigers or Seattle Mariners.

Those teams are set to decide their playoff series Friday in Game 5 at Seattle.

Ryan McMahon homered for the wild-card Yankees, unable to stave off elimination for a fourth time this postseason as they failed to repeat as AL champions.

Despite a terrific playoff performance from Aaron Judge following his previous October troubles, the 33-year-old star slugger remains without a World Series ring. New York is still chasing its 28th title and first since 2009.