Distribution and Quantification of Infectious and Parasitic Agents in Managed Honeybees in Central Italy, the Republic of Kosovo, and Albania

This study, conducted jointly by diagnostic institutes from Italy and the Republic of Ko-sovo/Albania, aimed to determine the occurrence of relevant infectious and parasitic agents (IPAs) in managed honeybees from these geographical areas to assess the overall health status of local apiaries. Paenibacillus larvae, Melissococcus plutonius, Nosema ceranae, Nosema apis, acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus variants DWV-A and DWV-B, and the para-sitoid flies Megaselia scalaris and Senotainia tricuspis were detected by quantitative poly-merase chain reaction (qPCR) and reverse transcriptase qPCR (RT-qPCR) in clinically healthy adult honeybees collected from 131 and 56 apiaries in the Abruzzo and Molise re-gions of Central Italy in 2022 and 2023, respectively, from 140 apiaries in the Republic of Kosovo and 18 in Albania in 2022, and from 66 apiaries in the Republic of Kosovo in 2023. The percentages of positive samples and abundance levels for N. ceranae, P. larvae and DWV-B were significantly higher in the Republic of Kosovo and Albania, while the per-centages of samples positive for M. plutonius, CBPV, DWV-A, and the parasitoid flies were higher in Central Italy. Additionally, P. larvae and some viruses showed significantly dif-ferent occurrence rates between the two years in Italy and the Republic of Kosovo. The co-occurrence of IPAs also differed between the two geographic areas. Their varying dis-tribution could depend on epidemiological dynamics, climatic factors, and management practices specific to each country, whose relative impact should be defined to guide tar-geted interventions to reduce honeybee mortality.