Publications by authors named "Anna Heitmann"

Background: The incidence of human infections caused by arthropod-borne viruses, such as the chikungunya virus (CHIKV), has increased globally due to a number of factors, such as climate change and globalization. The exotic mosquito species Aedes albopictus is a significant vector for CHIKV, raising concerns about its transmission potential in temperate regions, including Central Europe. We have therefore investigated the vector competence of Ae.

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The Usutu Virus (USUV) is a mosquito-borne flavivirus originated in Africa. The virus circulates in Germany since 2010. It is primarily transmitted and maintained in the natural cycle by mosquitoes and primarily affects birds, particularly Eurasian blackbird (), leading to significant mortality.

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The common house mosquito () is a native vector for West Nile virus (WNV). Invasive species like the tiger mosquito () and Asian bush mosquito () are rapidly spreading through Europe, posing a major threat as vectors for dengue, chikungunya (CHIKV), and Japanese encephalitis virus (JEV). These mosquitoes share a similar ecological niche as larvae, but the carry-over effects of aquatic larval interactions to the terrestrial adult stage remain largely unknown and their medical relevance requires further investigation.

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Background: Batai virus (BATV) is a zoonotic arbovirus of veterinary importance. A high seroprevalence in cows, sheep and goats and infection in different mosquito species has been observed in Central Europe. Therefore, we studied indigenous as well as exotic species of the genera Culex and Aedes for BATV vector competence at different fluctuating temperature profiles.

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Snowshoe hare virus (SSHV) is a zoonotic arthropod-borne virus (arbovirus) circulating in colder areas of the Northern Hemisphere. SSHV is maintained in an enzootic cycle between small mammals and mosquitoes, assumably of the genera and . Symptoms of SSHV human infection can range from asymptomatic to severe neuroinvasive disease.

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Phlebotomine sand flies (Diptera: Phlebotominae) are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). In Central Europe, Phlebotomus mascittii is the predominant species, but largely understudied.

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Background: Aedes japonicus japonicus (Theobald, 1901) and Aedes koreicus (Edwards, 1917) have rapidly spread in Europe over the last decades. Both species are very closely related and occur in sympatry. Females and males are difficult to distinguish.

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The West Nile Virus (WNV) and Sindbis virus (SINV) are avian-hosted mosquito-borne zoonotic viruses that co-circulate in some geographical areas and share vector species such as and . These are widespread in Europe, including northern parts and Finland, where SINV is endemic, but WNV is currently not. As WNV is spreading northwards in Europe, we wanted to assess the experimental vector competence of Finnish and mosquitoes to WNV and SINV in different temperature profiles.

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Transmission of arthropod-borne viruses (arboviruses) are an emerging global health threat in the last few decades. One important arbovirus family is the , including the species within the genus . Sindbis virus (SINV) is transmitted by mosquitoes, but available data about the role of different mosquito species as potent vectors for SINV are scarce.

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The global spread of invasive mosquito species increases arbovirus infections. In addition to the invasive species and has spread within Central Europe. Extensive information on its vector competence is missing.

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Reassortment is a viral genome-segment recomposition known for many viruses, including the orthobunyaviruses. The co-infection of a host cell with two viruses of the same serogroup, such as the and the can give rise to novel viruses. One example is the Ngari virus, which has caused major outbreaks of human infections in Central Africa.

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Background: Vector-borne diseases (VBD) are of growing global importance. Sand flies are potential vectors for phleboviruses (family Phenuiviridae) including Toscana virus (TOSV), Sicilian virus, Sandfly fever, Naples virus, and Leishmania parasites in Europe. To date, only two phlebotomine species have been recorded for Germany: Phlebotomus perniciosus and Phlebotomus mascittii.

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The global spread of the Asian tiger mosquito Aedes albopictus is of concern, as this mosquito species constitutes an important vector of a number of emerging pathogens including dengue virus, chikungunya virus and Zika virus. Since its first appearance in Albania (1979) and Italy (1990), the species has been reported from more than twenty-five European countries. However, the dispersion process in Europe is largely unknown, as information on population genetic structure is lacking, which is relevant to understand the observed spread.

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The continuous circulation of West Nile virus (WNV) in Central, South and East Europe and its recent detection in several dead birds and two horses in Germany highlights the need for information on WNV vector competence of mosquitoes from Central Europe. Therefore, three common species ( biotype , biotype and ) from Germany were orally infected with WNV and kept at 18 °C, 21 °C, 24 °C or 27 °C for 14 or 21 days post infection (dpi). Thereafter viable WNV was present in the saliva in all tested taxa, but only at incubation temperatures of 24 °C or 27 °C and predominantly at the extended incubation period of 21 dpi.

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The invasive mosquito species Aedes japonicus japonicus (Ae. japonicus) is widely distributed in Central Europe and is a known vector of various arboviruses in the laboratory, including flaviviruses such as Japanese Encephalitis virus or West Nile virus. However, the vector competence of Ae.

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Article Synopsis
  • Many insect cell lines are often infected with insect-specific viruses (ISV) that go unnoticed, raising concerns about their impact on research.
  • The study focuses on Culex Y virus (CYV), using methods like small RNA sequencing, electron microscopy, and PCR to detect the virus in mosquito cell lines Aag2, U4.4, and C7-10.
  • The presence and varying levels of CYV-specific small RNAs suggest that ISV infections could affect arbovirus co-infections, which is important for understanding their behavior in mosquito cells related to public health issues.
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Vector competence is defined as the potential of a mosquito species to transmit a mosquito-borne virus (mobovirus) to a vertebrate host. Viable virus particles are transmitted during a blood meal via the saliva of an infected mosquito. Forced salivation assays allow determining the vector potential on the basis of single mosquitoes, avoiding the use of animal experiments.

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Article Synopsis
  • - The Asian tiger mosquito has spread in southern Europe and has contributed to local outbreaks of chikungunya fever (CHIKV) in France and Italy over the last decade.
  • - A study analyzed how temperature affects the transmission risk of CHIKV by testing infected mosquitoes at various temperatures (18°C, 21°C, and 24°C), finding high transmission rates, especially at lower temperatures.
  • - The risk of CHIKV transmission in Europe is more dependent on the distribution of the mosquito vector rather than temperature, suggesting the need for better monitoring and control strategies in European countries with these mosquito populations.
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Article Synopsis
  • The Rift Valley fever virus (RVFV) is transmitted to humans and livestock by various mosquito species, and RNA interference (RNAi) may play a key role in controlling its replication.
  • Research shows that infected mosquito cells and RVFV-carrying mosquitoes produce virus-specific small RNAs, indicating that RNAi functions similarly in mosquitoes as it does in other model insects.
  • The study suggests that RVFV does not have a mechanism to suppress RNAi, highlighting its potential significance as a defense mechanism against the virus in mosquitoes.
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Mosquitoes collected in Germany in 2016, including Culex pipiens pipiens biotype pipiens, Culex torrentium and Aedes albopictus, as well as Culex pipiens pipiens biotype molestus (in colony since 2011) were experimentally infected with Zika virus (ZIKV) at 18 °C or 27 °C. None of the Culex taxa showed vector competence for ZIKV. In contrast, Aedes albopictus were susceptible for ZIKV but only at 27 °C, with transmission rates similar to an Aedes aegypti laboratory colony tested in parallel.

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Plasmodium parasites are transmitted by Anopheles mosquitoes to the mammalian host and actively infect hepatocytes after passive transport in the bloodstream to the liver. In their target host hepatocyte, parasites reside within a parasitophorous vacuole (PV). In the present study it was shown that the parasitophorous vacuole membrane (PVM) can be targeted by autophagy marker proteins LC3, ubiquitin, and SQSTM1/p62 as well as by lysosomes in a process resembling selective autophagy.

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Plasmodium parasites express a potent inhibitor of cysteine proteases (ICP) throughout their life cycle. To analyze the role of ICP in different life cycle stages, we generated a stage-specific knockout of the Plasmodium berghei ICP (PbICP). Excision of the pbicb gene occurred in infective sporozoites and resulted in impaired sporozoite invasion of hepatocytes, despite residual PbICP protein being detectable in sporozoites.

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Recently it has been shown in rodent malaria models that immunisation with genetically attenuated Plasmodium parasites can confer sterile protection against challenge with virulent parasites. For the mass production of live attenuated Plasmodium parasites for vaccination, safety is a prerequisite. Knockout of a single gene is not sufficient for such a strategy since the parasite can likely compensate for such a genetic modification and a single surviving parasite is sufficient to kill an immunised individual.

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Plasmodium cysteine proteases are essential for host-cell invasion and egress, hemoglobin degradation, and intracellular development of the parasite. The temporal, site-specific regulation of cysteine-protease activity is a prerequisite for survival and propagation of Plasmodium. Recently, a new family of inhibitors of cysteine proteases (ICPs) with homologs in at least eight Plasmodium species has been identified.

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Plasmodium parasites must control cysteine protease activity that is critical for hepatocyte invasion by sporozoites, liver stage development, host cell survival and merozoite liberation. Here we show that exoerythrocytic P. berghei parasites express a potent cysteine protease inhibitor (PbICP, P.

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