Shamonda virus reaches Vorarlberg cattle

The Shamonda virus has been detected in individual cattle in Vorarlberg as it spreads among herds in several European countries, ORF reported. Exact infection figures are unavailable because the disease is not subject to mandatory reporting.

Vorarlberg state veterinarian Norbert Greber described the virus as “exotic” and said positive test results had already been recorded in individual cases. The actual number of infections could be considerably higher.

Symptoms can be severe

The virus, which originally occurred in Africa, is mainly transmitted by gnats, a small type of mosquito, according to current knowledge. The same type of transmission is associated with bluetongue disease and the closely related Schmallenberg virus.

Possible symptoms in cattle include fever, watery diarrhoea, a significant drop in milk production, respiratory problems, loss of appetite and being unable to stand. Animals may also experience severe difficulty walking.

Austria has only had an AGES test capable of detecting the virus for around two weeks. Before that, an infection could only be suspected based on symptoms. According to the Austrian Chamber of Agriculture, Vorarlberg is now one of five Austrian provinces where the virus has been detected in cattle since mid-August.

Greber urged farmers to call a veterinarian at an early stage. Symptomatic treatment can prevent an animal’s condition from worsening and can help prevent a bacterial infection from developing alongside the viral infection. Such a combination can cause a cow to die, although the Austrian Chamber of Agriculture said deaths in cattle herds had so far been nonexistent or rare in connection with the virus.

Possible risks to unborn calves

The consequences for unborn calves remain unclear if their mothers become infected. Transmission from the mother to the unborn calf is considered likely. Greber said specialist literature indicated that the virus could affect unborn calves depending on the stage of pregnancy.

Many cattle are currently pregnant, so possible effects could become apparent in the coming weeks and months. The Austrian Chamber of Agriculture said it was still difficult to assess whether, and to what extent, infections in pregnant animals could damage foetuses or cause abortions.

Spread through insect bites

The virus is transmitted by gnats. Greber said climate change had probably contributed to its spread in the region, as warm weather increases gnat activity and therefore transmission. He said local cattle currently had no antibodies, but were likely to develop immunity soon.

As is typical of insect-borne diseases, one, two or three animals in a farm may become infected after being bitten by an infected insect. The entire herd is not usually affected because the virus cannot be transmitted from one cow to another.

No effect on humans

Greber said the virus had no effect on humans. Germany’s Friedrich Loeffler Institute, the federal research institute for animal health, also said there was currently no evidence that people could become infected with or fall ill from the virus.

The newly introduced European variant has also been spreading in neighbouring Germany since July. Südwestrundfunk reported that cattle on many farms in Upper Swabia and the German Lake Constance region had tested positive. The virus has also been detected in Switzerland and France.