Previous studies on horseshoe bats (Rhinolophus spp.) have described many coronaviruses related to SARS-CoV (SARSCoVr) in China and only a few coronaviruses related to SARS-CoV-2 (SARSCoV2r) in Yunnan (southern China), Cambodia, Laos and Thailand. Here, we report the results of several field missions carried out in 2017, 2021 and 2022 across Vietnam during which 1,218 horseshoe bats were sampled from 19 locations. Sarbecoviruses were detected in 11% of faecal RNA extracts, with much more positives for Rhinolophus thomasi (46%). We assembled 38 Sarbecovirus genomes, including 32 SARSCoVr, four SARSCoV2r; and two recombinants of SARSCoVr and SARSCoV2r (RecSar), one showing a Spike protein very similar to SARS-CoV-2. We detected a bat co-infected with four coronaviruses, including two sarbecoviruses. Our analyses revealed that Sarbecovirus genomes evolve in Vietnam under strong geographic and host constraints. First, we found evidence for a deep separation between viruses from northern Vietnam and those from central and southern Vietnam. Second, we detected only SARSCoVr in Rhinolophus thomasi, both SARSCoVr and SARSCoV2r in Rhinolophus affinis, and only RecSar in Rhinolophus pusillus captured close to the border with China. Third, the bias in favour of Uracil in synonymous third codon-positions of SARSCoVr viruses showed a negative correlation with latitudes. Our results also provided support for an emergence of SARS-CoV in horseshoe bats from northern Yunnan and emergence of SARS-CoV-2 in horseshoe bats from northern Indochina subtropical forests (southern Yunnan, northern Laos and north-western Vietnam).

Hyalomma ticks are important vectors of Crimean-Congo Haemorrhagic Fever Virus (CCHFV) and other pathogens. They are frequently carried as immatures from Africa, the Middle East and Mediterranean areas to temperate Europe via migratory birds and emergence of its adults has been reported in many countries where it has so far been non-endemic. Our aim was to implement the first steps of the DAMA (Document, Assess, Monitor, Act) protocol by monitoring the potential arrival of adult Hyalomma ticks in Hungary applying citizen-science methods. Ticks were collected from April-December 2021 by asking volunteer participants through a self-made website to look for unusual hard ticks on themselves, their pets and livestock. Owing to the intensive media campaign, the project website had over 31 thousand visitors within seven months and 137 specimens and several hundreds of photos of hard ticks were submitted by citizen scientists from all over the country. Beside Ixodes ricinus, Dermacentor reticulatus, Dermacentor marginatus and Haemaphysalis inermis, a specimen from a dog was morphologically identified as a male Hyalomma marginatum and another removed from a cattle as a male Hyalomma rufipes. The dog and the cattle had never been abroad, they were approximately 280 km apart, thus the two Hyalomma observations can be considered as separate introductions. Amplification of the partial mitochondrial cytochrome C oxidase subunit I gene was successful for both specimens. Sequencing verified the previous morphological identification for both ticks. Based on the phylogenetic analyses the Hy. marginatum individual most likely belongs to the Eurasian population and the Hy. rufipes to a clade of mixed sequences from Europe and Africa. We summarize the scattered historical reports about the occurrence of Hyalomma ticks and CCHFV in Hungary. Our data highlight the effectiveness of citizens science programmes in the monitoring and risk assessment of CCHFV emergence and preparedness in our region.