Infectious diseases - Authorities anticipate spread of Tigermouse in the North
The Lower Saxony State Health Office (NLG) expects the spread of the Asian Tiger Mosquito to also occur in the north and therefore expands insect surveillance. "So far, it has been mainly in the Oberrhein region in Baden-Württemberg, but it has now been detected in Bavaria, Thuringia and Berlin," said Virologist Masyar Monazahian of the NLG to the German Press Agency in Hannover. "In the future, the northern federal states will certainly be affected as well."
The day-active Tiger Mosquito can transmit pathogens such as the Dengue Virus or the Chikungunya Virus. The Robert Koch Institute (RKI) also expects that the Asian Tiger Mosquito will continue to spread from the south-west in Germany.
When a mosquito bites a person infected with Dengue Fever, it can transmit the pathogen to the next person it bites. The RKI reported in May of a high number of reported Dengue Fever cases due to travelers returning from tropical countries. In rare cases, the disease can lead to severe courses or even death.
According to Monazahian, mosquitoes in Lower Saxony are systematically monitored, specifically in the Hanover region and in the districts of Hildesheim, Cuxhaven and Wilhelmshaven. In this year, additional traps have been set up - at locations where it is suspected that the Tiger Mosquito could have been imported through trade, flower trade or seaports, for example near the Dutch border.
Two findings of exotic mosquitoes in Hannover
Citizens can suspect mosquitoes they find and have them examined by the virologist at the health office. A corresponding nationwide project - the so-called Mosquito Atlas - has been running successfully since 2012 and is based at the Leibniz Centre for Agricultural Landscape Research and the Friedrich-Loeffler-Institute.
The NLG was informed by the project in March that an Asian Tiger Mosquito had been found in Hannover-Hainholz and Hannover-Kirchrode. Monazahian reported that no further specimens of the species were found around the discovery sites - the two specimens were likely brought in by car or suitcase from other parts of Germany or Europe.
Due to the heavy rainfall in the past months, rain barrels, puddles and stream beds are well filled with water - the warm, humid weather is ideal for insects. Biologist Doreen Werner, initiator of the nationwide Mosquito Atlas, reported that there are currently no mosquito infestations in the north. "We don't feel plagued yet, but it's not a mosquito infestation yet." The researcher from the Leibniz Centre for Agricultural Landscape Research in Müncheberg (Brandenburg) emphasized: "We currently feel bothered, but it's not yet a mosquito infestation."
The Hamburg Institute for Hygiene and the Environment, in collaboration with the Bernhard-Nocht-Institute for Tropical Medicine in Hamburg Port, are also searching for invasive mosquitoes in a project. The goal is to detect the introduction of exotics as early as possible. Mosquito traps have been set up in cargo rooms of ships. According to the authorities, no invasive species were discovered in 2023, the evaluation for 2024 is still running.
A Horse with West Nile Virus
However, domestic mosquitoes can also transmit various disease carriers such as the West Nile Virus. However, only 20% of those affected fall ill, 80% remain asymptomatic. Mosquitoes transmit this virus from bird to bird. Humans or horses are dead-end hosts. This means that they get sick but cannot further transmit the virus.
According to NLG Virologists, the West Nile Virus was detected in Lower Saxony at the beginning of the year in a horse in the County of Bentheim. "That's why we also set up a trap there." In Eastern Germany, according to RKI, there are several West Nile virus transmissions every year that do not originate from travelers returning from trips.
In general, mosquito bites are only annoying, the transmission of disease carriers is very rare. If they become inflamed, this is due to the fact that one scratches and thus introduces dirt particles and bacteria.
Mosquito Atlas
- The Asian Tiger Mosquito, known to transmit pathogens like the Dengue Virus and Chikungunya Virus, is anticipated to spread further north in Germany, according to predictions by the Lower Saxony State Health Office (NLG).
- The NLG has expanded its insect surveillance in response to the anticipated spread of the Asian Tiger Mosquito, which has already been detected in Bavaria, Thuringia, and Berlin, beyond its initial habitat in Baden-Württemberg's Oberrhein region.
- Virologist Masyar Monazahian of the NLG highlighted that mosquitoes in Lower Saxony and specifically in Hannover, Hildesheim, Cuxhaven, and Wilhelmshaven districts are being monitored closely.
- Monazahian mentioned that additional traps have been installed this year in locations suspected for the arrival of the Tiger Mosquito through trade, flower trade, or seaports, such as near the Dutch border.
- Two specimens of the Asian Tiger Mosquito were discovered in Hannover-Hainholz and Hannover-Kirchrode in March by the Mosquito Atlas project.
- No further specimens of the species were found near the discovery sites, but Monazahian believes they were likely brought in by car or suitcase from other German or European areas.
- Since 2012, the Mosquito Atlas project has been monitoring exotic mosquitoes nationwide, based on the Leibniz Centre for Agricultural Landscape Research and the Friedrich-Loeffler-Institute.
- Scientist Doreen Werner, responsible for the Mosquito Atlas, reported no mosquito infestations in the north, but noted the concern that conditions are favorable for mosquito breeding with the recent heavy rainfall and warm weather.
- In a collaboration with the Bernhard-Nocht-Institute for Tropical Medicine, the Hamburg Institute for Hygiene and the Environment continues its search for invasive mosquitoes, aiming to detect the introduction of exotics as early as possible.
- In Schleswig-Holstein, the Robert Koch Institute (RKI) is carrying out projects on the spread of infectious diseases, including the West Nile Virus, using modern scientific strategies and methods.
- In 2023, no invasive species were discovered during the Hamburg project, while the evaluation for 2024 is still ongoing.
- According to RKI, in Eastern Germany, several West Nile virus transmissions occur annually, which do not originate from travelers returning from trips.
- In summary, although mosquito bites can be irritating and introduce bacteria leading to inflammation, the transmission of disease carriers occurring as a result is relatively rare in Germany.
