Honey bee (Apis mellifera L.) colonies as bioindicators of environmental SARS-CoV-2 occurrence

Abstract

SARS-CoV-2 is responsible for the COVID-19 pandemic. Airflows sustain the infection spread, and in densely urbanized areas airborne particulate matters (PMs) are deemed to aggravate the viral transmission. Apis mellifera colonies are used as bioindicators as they allow environmental sampling of different nature, PMs included. This experiment demonstrates for the first time the possible use of honey bee colonies in the SARS-CoV-2 monitoring. The trial was conducted in Bologna on 18 March 2021, when the third wave of the Italian pandemic was at its peak and environmental conditions allowed high PM concentrations in the air. Sterile swabs were lined up at the hive entrance to sample the dusty material on the body of returning foragers. All of them resulted positive for the target genes of viral SARS-CoV-2 RNA. Likewise, internal samples were taken, but they resulted in no amplification of the target sequences. This experiment does not support speculations about the role of honey bees or their products in SARS-CoV-2 transmission. However, it indicates a novel use of A. mellifera colonies in the environmental detection of airborne human pathogens, at least in a densely urbanized area, deserving better understanding and possible integration with data from automatic air samplers.

Droplet Digital RT-PCR (dd RT-PCR) Detection of SARS-CoV-2 in Honey Bees and Honey Collected in Apiaries across the Campania Region

“…Since in farm animals such as buffaloes, goats, sheep, horses, rabbits, hens, pigs, or cows, SARS-CoV-2 has not been detected despite contact with their infected breeders [44], we can exclude the contamination of samples from operators' coughing and sneezing or from the passage of fomites to honey bees, and the environmental contamination of honey bees must be assumed. So, in accordance with other studies [35,45], our results showed that in the future, honey bees could very likely be used as indicators of outbreaks of airborne pathogens. Furthermore, by providing evidence that the molecular characterization of the pathogens detected in honey bee samples is also technically feasible, this study opens the possibility of using this approach for the identification and mapping of emerging diseases.…”

“…In fact, it was observed that honey bee colonies have a higher sample capacity than an automatic environmental monitoring station, because the honey bee body has a maximum diameter of 4.5 mm [46,47], and considering that one forager may leave the hive twenty times per day flying each time for 500 m [48], it can be said that even one single honey bee can come in contact with an approximate daily volume of air of 0.16 m 3 [49][50][51]. Assuming that in a colony there are 2000 foragers [49][50][51], those last bees may encounter 318 m 3 of air per day, from which airborne PMs may be sampled using their hairs and brought to the colony, Test period 0 500,000 1,000,000 1,500,000 2,000,000 So, in accordance with other studies [35,45], our results showed that in the future, honey bees could very likely be used as indicators of outbreaks of airborne pathogens. Furthermore, by providing evidence that the molecular characterization of the pathogens detected in honey bee samples is also technically feasible, this study opens the possibility of using this approach for the identification and mapping of emerging diseases.…”

“…In particular, it has been shown that when exposed to airborne particles, they can capture PM through adhesion to their body hairs [33,34]. Therefore, honey bee colonies can be used as bioindicators of environmental SARS-CoV-2 occurrence in the application of epidemiological monitoring plans [35].…”

First molecular detection of SARS-CoV-2 virus in cockroaches

“…A recently conducted study in Italy showed that SARS-CoV-2 could be detected in the particulate matter carried by honey bee foragers, in this study foraging honey bees were positive for the target genes of viral SARS-CoV-2 RNA when coming back to the colony (Cilia et al 2022 ).…”

Holobiont Urbanism: sampling urban beehives reveals cities’ metagenomes

“…Furthermore, metagenomic data can be mined for human-health related information [ 59 ]. Future uses of data collected in this manner could be assessment of antibiotic resistance gene profiles, and while the molecular and computational methods used here were based on DNA analysis, it is possible they could be used to monitor RNA-based viruses such as Sars-Cov-2 or other future airborne pathogens, as demonstrated by targeted analyses using swab-based collection at hive doors during the COVID19 global pandemic [ 60 ].…”