Summary
There is a contiguous outbreak of hepatitis A cases in at least four European countries. ECDC has published a risk assessment.
In France, 761 cases of chikungunya have already been reported this year, including some locally acquired cases.
A new SARS-CoV-2 variant has been categorised by the WHO and ECDC as a "variant under observation".
In the topic of the month, we explain what pigs have to do with hepatitis E in humans and how the spread can be contained.
In the news section, we present the 2024 annual reports of the National Reference Centres for Diphtheria, Campylobacter, Listeriosis and the Rabies Advisory Centre. In addition, trachoma was eliminated in Burundi and Senegal and Suriname was declared malaria-free .
As reported in the last Radar, cases of hepatitis A are on the rise in Austria. So far in 2025, 128 cases of hepatitis A have been reported (as of 14 July 2025), compared to 74 cases in the previous year as a whole. The Institute of Infectious Disease Epidemiology at AGES is investigating this cluster of hepatitis A cases. The situation is being continuously monitored so that protective measures can be taken if necessary.
The situation is similar in other European countries. The European Centre for Disease Prevention and Control (ECDC) published a risk assessment of the transnational hepatitis A outbreak on 18 June:
In addition to Austria, at least the Czech Republic, Hungary and Slovakia are affected. Together, the four countries have reported a total of 2,097 cases (as of 18 June 2025). The increase in hepatitis A virus infections mainly affects homeless people, people who use or inject drugs and those who live in poor sanitary conditions and have limited access to healthcare. Cases have also been reported among members of the Roma communities in the Czech Republic and Slovakia.
Genetic sequencing of the viruses suggests that there is ongoing person-to-person transmission within connected social networks, rather than multiple, unrelated outbreaks. Further spread within these networks is considered likely. The ECDC therefore makes the following recommendations:
- Continued investigation of hepatitis A transmission routes and increased sequencing to understand the full epidemiological picture
- Targeted vaccination of population groups that are more at risk (already being carried out in Austria)
- Ensure easy access to basic hygiene such as soap and water for people who are more at risk in areas accessible to them such as public toilets, homeless shelters and food banks
- Tailor education and activities to vulnerable populations. Provide information in multiple languages, adapted to different literacy levels, and address rumours and misinformation that may be circulating
In France, 761 imported cases of chikungunya were registered this year (as of 8 July 2025), already a multiple compared to the entire previous year, in which 34 imported chikungunya cases were reported. Most of the imported cases had previously been in the French overseas territory of La Réunion. A chikungunya outbreak has been underway in La Réunion since last year, with over 54,000 cases since the beginning of 2025.
In addition, 25 autochthonous cases have been registered - i.e. those who must have been infected within France due to a lack of travel history(ECDC, as of 09.07.2025).
This is unusual in several respects:
- Autochthonous cases have not yet occurred so frequently in France. The first two autochthonous cases of chikungunya were observed in France in 2010. Since then, there have only been 11 and 17 locally acquired infections in 2014 and 2017 respectively
- While most autochthonous cases have so far occurred in southern regions of France near the Mediterranean coast, more northerly regions have also been affected this year. In July 2025, for example, the Bas-Rhin department, which is located close to the border with Germany, reported an autochthonous case for the first time. The affected person had only been in the region south of Strasbourg and was most likely bitten by an infected louse there
- The first autochthonous cases on the French mainland (including Corsica) occurred in May/June this year, which is earlier than in previous years, when cases were only observed in July or August
The chikungunya virus is transmitted by mosquitoes, mainly yellow fever and tiger mosquitoes. The disease usually manifests itself in fever, severe joint, limb and muscle pain, which can last for weeks to months after the fever has passed. The disease usually subsides on its own after one to two weeks and leaves lifelong protection. Older people in particular are at risk of a severe course.
The chikungunya virus is not endemic in Europe, with the exception of some overseas regions. Most of the infections detected in Europe are imported; the people affected have been infected by the bite of an infected mosquito while travelling in countries where the virus is endemic or where chikungunya outbreaks are currently taking place. If these infected people are bitten by mosquitoes shortly after returning from travelling, which can pick up and pass on the virus during a blood meal, local transmission is possible. One of these mosquito species is the Asian tiger mosquito, which has now established itself in France and other parts of Europe. The more imported cases and the larger the tiger mosquito population, the higher the risk of local transmission. As the tiger mosquito is also becoming established in Austria, local transmission is also possible in Austria.
On 15 July 2025, at least one case of local infection was also confirmed in Italy, in the province of Piacenza.
To avoid infection with the chikungunya virus, it is advisable to wear mosquito repellent. Even after returning from endemic areas, care should be taken to use personal mosquito repellent to prevent mosquitoes from infecting themselves with the virus and passing it on to other people locally.
An essential measure to contain the spread of the virus is to avoid breeding sites for mosquitoes, for example by emptying water containers at least once a week and closing rain barrels.
As a doctor , a chikungunya infection should be considered in patients with corresponding symptoms even without a travel history.
In Austria, a recently available vaccination against chikungunya is recommended for travellers to endemic areas and in cases of epidemiological risk from the age of 12 as well as for exposed laboratory personnel.
On 11 July 2025, the European Medicines Agency (EMA) lifted the temporary ban on vaccination for people over 65. This came into force in June after serious side effects occurred in people over 65. The committee concludes that the vaccination should only be administered to all people, regardless of age, if there is a significant risk of chikungunya infection and the risk/benefit has been carefully weighed up.
In Austria, 6 imported chikungunya cases have been reported so far this year (as of 16 July 2025, see tables).
Data on chikungunya, dengue and Zika in France
Epidemiological bulletin 28/2025
At the end of June, the ECDC and the WHO assigned the SARS-CoV-2 variant XFG to the "variant under observation" category, in addition to the variants NB.1.8.1 and LP.8.1. XFG is increasing globally and is gaining ground over other circulating variants. In Austria, the proportion of this variant detected in wastewater monitoring recently totalled up to almost 40 %. It is still too early to assess what epidemiological impact this variant will have on the EU or the EEA. The WHO estimates the additional health risk of the variant to be low. At the same time, the ECDC has de-escalated the KP.3 and XEC variants, which are no longer "of particular interest" or "under observation".
In recent weeks, an increase in the indicators for SARS-CoV-2 infections has been observed in several European countries. However, the overall number of infections remains low and the impact on hospital admissions is also limited. As many countries have not reported any figures since the end of the winter and there is hardly any testing, it is difficult to fully interpret the situation.
After a slight increase in June, the SARS-COV-2 concentration in Austrian wastewater has levelled off again. The same was observed in the COVID-19 sentinel system: A temporary increase in COVID-19 cases in mid-June with a subsequent decrease. Inpatient hospital admissions are also at a low level. For comparison: 28 admissions to normal wards in the last week of June, over 900 admissions at the peak of the last COVID-19 wave in October 2024.
Due to a low Sars-CoV-2 circulation in the past winter season, a decrease in immunity in the population can be assumed, which could lead to an increase in the number of infections in the summer months. People at increased risk in particular should follow the recommendations for COVID-19 booster vaccinations.
SARS-CoV-2 variants of concern as of 27 June 2025
Epidemiological update: SARS-CoV-2 and NB.1.8.1 variant assessment
Hepatitis E is an inflammation of the liver caused by the hepatitis E virus (HEV). Compared to other hepatitis viruses, HEV has a special feature: the viruses can also be transmitted to humans via pork products. There are four different genotypes worldwide, whereby genotypes 3 and 4 have been found not only in humans but also in pigs. HEV is a zoonotic disease, i.e. an infectious disease that can be transmitted between animals and humans. In order to prevent the spread of the disease, a comprehensive approach is needed that considers livestock farming, food production and human health together.
Hepatitis E is usually a harmless disease in this country; most people who become infected with hepatitis E show no or only mild symptoms such as tiredness, nausea, vomiting, upper abdominal pain and fever. Severe cases are very rare and the infection usually heals without permanent consequences. Pregnant women, elderly or immunocompromised people have a higher risk of a severe course and of dying from the disease. Fatalities are very rare and account for less than one per cent of reported cases.
The number of reported cases in humans has risen sharply in Europe in recent years. In Germany, the annual number of cases has risen from around 50 to almost 5,000 since 2005, whereas this trend is much less pronounced in Austria (see Figure 1). The German Robert Koch Institute (RKI) assumes that it is not the number of cases that is increasing, but that the rise is most likely due to increased attention from the medical profession, more frequent diagnosis and the use of more sensitive diagnostic tests. As many infections are asymptomatic, many infections are likely to be overlooked. There is no specific therapy and no vaccination authorised in Austria.
Pigs, HEV and prevention
Human-to-human spread has not yet been observed with HEV genotype 3, which is widespread in Europe. Transmission from pigs to humans probably plays the most important role here: insufficiently heated pork and raw meat products are likely to be the most common transmission routes. Correspondingly contaminated food could lead to increased cases of the disease regionally or even supraregionally. Transmission could also occur during the processing of pork, with butchers, veterinarians and hunters being at risk.
Pigs can be carriers of hepatitis E viruses, but they do not contract the disease. HEV is therefore less relevant for livestock farming, but possible transmission to humans is the reason for joint control and prevention measures by veterinary and human medicine.
The most important preventive measure is to cook pork thoroughly, i.e. to heat it completely to over 70 degrees Celsius. Immunocompromised persons should avoid products made from raw pork. The same applies to game meat, as wild boar and presumably deer can also be carriers of hepatitis E viruses.
HEV is now also being combated in pig farming and food production. One example of this is the "BIOPIGEE" project, in which AGES was involved: The project focussed on the question of how HEV and salmonella can be controlled and reduced in pig farming. Measures were developed along the entire production chain, from the barn to the slaughterhouse. Safety concepts for pig farms and abattoirs were developed and it was checked which steps are effective and cost-efficient. All results and tools developed from the project can be found on the project website.
HEV as the most common cause of liver inflammation
There are different variants of HEV - genotype 3 is the most common in Europe and North America, while humans are the only host for genotype 1, which occurs in Asia and Africa. This variant is responsible for HEV being the most common cause of liver inflammation worldwide. Transmission usually occurs through drinking water contaminated with faeces. This HEV genotype is extremely dangerous for pregnant women.
The spread is completely different from that of genotype 3, which is common in Austria, and requires different measures, especially hygiene, good sanitary facilities and clean drinking water.
When travelling to areas where genotype 1 or 2 is present, the RKI recommends following the general rules for avoiding food-borne infections:
- Avoid unboiled tap water and ice made with it for drinks
- Do not eat raw or insufficiently heated food
The 2024 annual report of the National Reference Centre for Listeriosis was published at the beginning of July.
Listeriosis continued to be a rare infectious disease in 2024, with an incidence of 0.48/100,000 inhabitants. The National Reference Centre (NRC) for listeriosis verified 44 human cases of invasive listeriosis in Austria. 12 deaths were documented, although it was not determined whether the cause of death was directly related to listeriosis. One case of listeriosis was pregnancy-associated. Both the mother and the child tested positive for listeria. Two listeriosis clusters were identified in Austria. AGES has been commissioned to clarify the outbreak in these clusters.
The 2024 annual report of the National Reference Centre Campylobacter was published at the beginning of July.
In 2024, 6,858 cases of campylobacteriosis were registered in Austria. The annual incidence was 74.9 cases per 100,000 inhabitants, which was higher than the average annual incidence of the last five years. One fifth of the cases infected with Campylobacter had to be hospitalised and ten people died. Most Campylobacter infections were observed in the summer months of June to August.
In 2024, extremely high or very high resistance rates for fluoroquinolones (C. jejuni 75.6 %, C. coli 86.1 %) and tetracyclines (C. jejuni 53.5 %, C. coli 51.5 %) were again observed. Macrolide resistance remained low (C. jejuni 0.2 %, C. coli 3.0 %).
Campylobacteriosis has been the most important food-associated gastrointestinal infection in the European Union for years, alongside salmonellosis.
We discussed campylobacter in barbecues in more detail in the AGES Radar issue of 23 May 2024.
The 2024 annual report of the National Reference Centre for Diphtheria Laboratory was published at the beginning of July.
In 2024, a total of 112 samples were tested at the National Reference Centre for Diphtheria Laboratory. Corynebacterium diphtheriae was detected in 33 samples and Corynebacterium ulcerans in seven samples. While no strain was toxigenic in C. diphtheriae, four toxigenic strains were identified in C. ulcerans.
Three patients met the case definition for diphtheria - two with cutaneous diphtheria, one with classical respiratory diphtheria, all with C. ulcerans. One death was recorded.
Particularly striking: all cases in 2024 were caused by Corynebacterium ulcerans - a zoonotic species that can be transmitted through animal contact or raw milk products, among other things.
Despite declining case numbers, the number of cases submitted remains higher than before 2022. This may be due to increased awareness in clinics and laboratories, among other things.
The annual report 2024 of the National Rabies Advisory Centre was published in July.
No human cases of rabies were documented in Austria in 2024.
At the National Reference Laboratory for Rabies, the Institute of Veterinary Medicine, 202 animals were tested for rabies, with foxes being the most frequently represented with 67 submissions and bats with 56 submissions.
These included 36 animals that had bitten a human - all with negative results; most of these were dogs and cats (15 dogs, 14 cats, 4 bats, 2 foxes and 1 rat).
In addition, the AGES Rabies Advice Centre conducted a total of 566 consultations in 2024, 386 of which were with private individuals in cases of questionable risk contact and 180 with healthcare professionals to clarify the administration of a possible post-exposure prophylaxis.
Suriname is malaria-free
The WHO has officially certified Suriname as the first country in the Amazon region to be malaria-free. This marks the end of an almost 70-year battle against the tropical disease, which began in the 1950s with insecticide sprays and anti-malaria treatments. For the indigenous population in remote rainforest regions and mobile mine workers, the recruitment and training of health personnel from the respective communities was essential. The expansion of diagnostic and treatment services also contributed to containment.
No more locally acquired cases have been registered in the last three years.
Suriname is now one of the 46 countries recognised as malaria-free by the WHO. The Americas region currently has twelve malaria-free countries.
Burundi and Senegal eliminate trachoma
Burundi and Senegal have eliminated trachoma as a public health problem. Trachoma is the first neglected tropical disease to be eliminated in Burundi. This was made possible in part by the introduction of interventions based on the SAFE strategy, which includes campaigns for surgical interventions, antibiotic administration, (facial) hygiene and improvement of water supply and general hygienic conditions.
Trachoma is a bacterial eye infection and the leading infectious cause of blindness worldwide. It is caused by the bacterium Chlamydia trachomatis and spreads through close physical contact, flies and contaminated surfaces. Repeated infections can lead to scarring, inward rotation of the eyelids and irreversible blindness.
Trachoma primarily affects regions with poor hygienic conditions and a lack of access to clean water. Since 2014, the number of trachoma patients requiring treatment in the African WHO region has fallen from 189 to 93 million. Burundi and Senegal are the eighth and ninth countries in the WHO African Region to have eliminated trachoma.
A disease is considered "eliminated as a public health problem" when a country reaches certain targets set by the WHO. Even after the disease has been officially eliminated as a public health problem, certain measures remain in place to ensure that these targets continue to be met.
Antigens are foreign body structures to which an organism can react by producing antibodies; antibodies have the function of recognising the antigens and fighting them inactivated. To do this, the antibodies must be able to bind to the antigens. The avidity describes how strongly an antibody binds to the antigen, the strength of a multiple bond between antigen and antibody. If the two molecules form only one bond, the avidity is low; if there are two bonds, the avidity is high and if there are more than two bonds (polyvalent), it is very high.
Avidity can be measured and provides information about when the infection occurred. If an infection is recent, the avidity is low; if it occurred a long time ago, it is high. This can be important during pregnancy, for example, as some infections can be particularly dangerous if they occur for the first time during pregnancy. An avidity test can be used to determine whether this is the case or whether an initial infection occurred some time ago and therefore no longer poses an acute risk.
The AGES Radar for Infectious Diseases is published monthly. The aim is to provide the interested public with a quick overview of current infectious diseases in Austria and the world. The diseases are briefly described, the current situation is described and, where appropriate and possible, the risk is assessed. Links lead to more detailed information. The "Topic of the month" takes a closer look at one aspect of infectious diseases.
How is the AGES radar for infectious diseases compiled?
Who: The radar is a co-operation between the AGES divisions "Public Health" and Risk Communication.
What: Outbreaks and situation assessments of infectious diseases:
- National: Based on data from the Epidemiological Reporting System (EMS), outbreak investigation and regular reports from AGES and the reference laboratories
- International: Based on structured research
- Topic of the week (annual planning)
- Reports on scientific publications and events
Further sources:
Acute infectious respiratory diseases occur more frequently in the cold season, including COVID-19, influenza and RSV. These diseases are monitored via various systems, such as the Diagnostic Influenza Network Austria (DINÖ), the ILI (Influenza-like-Illness) sentinel system and the Austrian RSV Network (ÖRSN). The situation in hospitals is recorded via the SARI (Severe Acute Respiratory Illness) dashboard.
Austrian laboratories send SARS-CoV-2 samples to AGES for sequencing. The sequencing results are regularly published on the AGES website.
For the international reports, health organisations (WHO, ECDC, CDC, ...) specialist media, international press, newsletters and social media are monitored on a route-by-route basis.
For infectious diseases in Austria, the situation is assessed by AGES experts, as well as for international outbreaks for which no WHO or ECDC assessment is available.
Disclaimer: The topics are selected according to editorial criteria, there is no claim to completeness.
Suggestions and questions to:wima@ages.at
As the response to enquiries is also coordinated between all parties involved (knowledge management, INFE, risk communication), please be patient. A reply will be sent within one week.
Case numbers of notifiable diseases according to the Epidemics Act, the figures are shown for the previous month and, in each case for the period from the beginning of the year to the end of the previous month, the figures for the current year, for the previous year, as well as the median of the last 5 years for comparison (Epidemiological Reporting System, as of 16 July 2025).
| Pathogens | 2025 | 2024 | 2020-2024 (median) | |
|---|---|---|---|---|
| May | Jan-May | Jan-May | Jan-May | |
| Amoebic dysentery (amoebiasis) | 1 | 4 | 9 | 4 |
| Botulism b | 0 | 0 | 0 | 0 |
| Brucellosis | 0 | 2 | 5 | 4 |
| Campylobacteriosis b | 699 | 2.758 | 3.008 | 2.666 |
| Chikungunya fever | 5 | 6 | 6 | 1 |
| Cholera | 0 | 0 | 0 | 0 |
| Clostridioides difficile infection, severe course | 49 | 419 | 412 | 281 |
| Dengue fever | 12 | 78 | 125 | 35 |
| Diphtheria | 0 | 2 | 1 | 1 |
| Ebola fever | 0 | 0 | 0 | 0 |
| Echinococcosis due to fox tapeworm | 0 | 11 | 17 | 9 |
| Echinococcosis caused by dog tapeworm | 3 | 8 | 14 | 14 |
| Spotted fever (rickettsiosis caused by R. prowazekii) | 0 | 0 | 0 | 0 |
| Tick-borne encephalitis (TBE) | 29 | 47 | 68 | 68 |
| Yellow fever | 0 | 0 | 0 | 0 |
| Haemophilus influenzae, invasive a | 4 | 67 | 56 | 28 |
| Hantavirus disease | 5 | 19 | 12 | 15 |
| Hepatitis A | 43 | 132 | 33 | 21 |
| Hepatitis B | 77 | 469 | 584 | 490 |
| Hepatitis C | 82 | 523 | 557 | 445 |
| Hepatitis D | 1 | 3 | 5 | 4 |
| Hepatitis E | 7 | 35 | 27 | 29 |
| Whooping cough (pertussis) | 88 | 1.296 | 7.402 | 195 |
| Polio (poliomyelitis) | 0 | 0 | 0 | 0 |
| Lassa fever | 0 | 0 | 0 | 0 |
| Legionnaires' disease (legionellosis) d | 36 | 165 | 146 | 123 |
| Leprosy | 0 | 1 | 0 | 0 |
| Leptospirosis | 1 | 5 | 14 | 4 |
| Listeriosis b | 5 | 17 | 22 | 19 |
| Malaria | 5 | 34 | 25 | 25 |
| Marburg fever | 0 | 0 | 0 | 0 |
| Measles | 28 | 137 | 463 | 25 |
| Meningococcus, invasive c | 2 | 21 | 10 | 8 |
| Middle East respiratory syndrome (MERS) | 0 | 0 | 0 | 0 |
| Anthrax | 0 | 0 | 0 | 0 |
| Mpox e | 0 | 12 | 10 | 10 |
| Norovirus gastroenteritis b | 101 | 2.423 | 2.328 | 1.150 |
| Paratyphoid fever | 0 | 0 | 1 | 1 |
| Plague | 0 | 0 | 0 | 0 |
| Pneumococcus, invasive c | 52 | 630 | 527 | 242 |
| Smallpox | 0 | 0 | 0 | 0 |
| Psittacosis | 0 | 0 | 2 | 2 |
| Rotavirus gastroenteritis b | 98 | 759 | 530 | 365 |
| Glanders (Malleus) | 0 | 0 | 0 | 0 |
| Rubella | 0 | 0 | 0 | 0 |
| Relapsing fever | 0 | 0 | 0 | 0 |
| STEC | 94 | 365 | 282 | 175 |
| Salmonellosis b | 129 | 533 | 456 | 425 |
| Scarlet fever | 21 | 177 | 469 | 2 |
| Severe acute respiratory syndrome (SARS) | 0 | 0 | 0 | 0 |
| Shigellosis b | 15 | 124 | 116 | 40 |
| Other viral meningoencephalitis | 15 | 77 | 58 | 58 |
| Rabies | 0 | 0 | 0 | 0 |
| Trachoma (grain disease) | 0 | 0 | 0 | 0 |
| Trichinellosis | 0 | 1 | 5 | 2 |
| Tuberculosis | 31 | 197 | 219 | 196 |
| Tularemia | 5 | 19 | 57 | 12 |
| Typhoid fever | 1 | 3 | 8 | 3 |
| Bird flu (avian influenza) | 0 | 0 | 0 | 0 |
| West Nile virus disease | 0 | 0 | 0 | 0 |
| Yersiniosis b | 6 | 36 | 63 | 63 |
| Zika virus disease | 0 | 2 | 9 | 0 |
a The diseases are assessed according to the case definition. Diseases for which a case definition exists are shown, with the exception of transmissible spongiform encephalopathies. As a rule, confirmed and probable cases are counted. Subsequent notifications or entries may result in changes.
b Bacterial and viral food poisoning, in accordance with the Epidemics Act.
c Invasive bacterial disease, in accordance with the Epidemics Act.
d Includes only cases with pneumonia.
e Mpox has been notifiable since 2022; the median is only calculated for the years in which notification is mandatory.
Last updated: 17.07.2025
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