Researchers have detected SARS-CoV-2 virus in cockroaches – they spread the virus in the environment and contaminate human food and various surfaces of buildings

Insect order is the most populous animal group with economic, medical, and veterinary importance. There has been a relationship and partnership between human health and some insects for a long time (Dent and Binks 2020).

However, in the nineteenth century, insects and other arthropods’ role in transmitting certain diseases to humans was established. Among these insects, cockroaches always affect human health and can be the vector of pathogenic bacteria and viruses and an intermediary host for intestinal worms and pathogenic protozoa.

They are one of the most important vectors in transmitting and spreading many human diseases. These Pathogens can live in Cockroaches’ internal and external body parts for several days, and they can and do distribute them. Contacts with the Cockroaches` external body or Feces to the Substances that humans deal with can lead to the transmission of these diseases (Patel et al. 2022; Roth and Willis 1957; Vahabi et al. 2007).

Respiratory coronaviruses, like rhinoviruses, can spread through direct contact with contaminated secretions or large aerosol droplets (Gomes 2020; Reed 1984). In addition, infected individuals can contaminate the surfaces they come into contact with, including many household goods and house appliances (Gomes 2020).

Preliminary research shows that coronaviruses, including the SARS-CoV-2 RNA virus, can remain on the surface for hours to days; This can vary depending on different circumstances, for example, surface type, environmental temperature, and humidity (Casanova et al. 2010; Farnoosh et al. 2020; Kampf et al. 2020).

A new study presented real-time RTPCR findings of fecal and respiratory samples from cases with SARS-CoV-2 in China showed respiratory samples remained positive for SARS-CoV-2 RNA for an average of 16.7 days, of the 41 (55%) of 74 cases and fecal samples remained positive for an average of 27.9 days after the first symptom start (Wu et al. 2020).

The laboratory transmission of turkey Coronavirus becomes evaluated with the aid of a species of beetle referred to as Alphitobius diaperinus (Coleoptera: Tenebrionidae). This study showed that turkey coronavirus could be transmitted mechanically with this insect (Watson et al. 2000).

Another study evaluates biological and mechanical transmission of the Reticuloendotheliosis virus by Culex pipiens and Musca domestica in vitro and in the field. The results showed that the mosquitoes had the virus in their bodies for up to 5 h, and houseflies survived the virus for up to 72 h. Although all field-collected samples were free of virus, this study shows houseflies are a possible mechanical vector of the virus (Davidson and Braverman 2005).

In another study in 2020, two of 13 flies (one housefly and one drosophila), as well as the mosquito pool of two individuals (not identified), tested positive for African swine fever virus DNA (ASFV-DNA) (Herm et al. 2020). It was previously shown that blood-sucking flies, such as stable flies, can transmit ASFV. It has also been experimentally demonstrated that stable flies can transmit ASFV by biting (Mellor et al. 1987) or through ingestion by pigs (Olesen et al. 2018).

An overview paper published in 2021 has been declared that contacting or feeding on human feces by an organism such as cockroaches may support SARS-CoV-2 transmission (Sharawi 2021).

In another study, the role of the American cockroach, Periplaneta americana, as a mechanical vector for Eimeria tenella was evaluated, and E. tenella oocysts were found in the digestive tract and feces of infected cockroaches up to day 4 after ingestion of oocysts. Oocysts recovered from the digestive tract and feces of cockroaches remained infective for 4 and 3 days for chickens, respectively (Jarujareet et al. 2019).

Another study in Thailand evaluates the in vitro transmission of the avian influenza virus (HPAI) subtype H5N1. 1500 adult flies were used in three groups. Group A had no contact with the virus, but groups B and C were exposed to the virus with food for 15 min. Group B was immediately homogenized and given to sensitive chickens. Group C was homogenized after 24 h.

The results showed group B and C intervention died, although the load of the virus was more in group B. This study showed that houseflies could mechanically transmit this viral disease among birds (Wanaratana et al. 2013). Another study in Japan showed blowflies could mechanically transmit H5N1 bird flu (Sawabe et al. 2011).

In a recent study in Iran, the in vitro infestation of the avian influenza virus (AIV) subtype H9N2 by houseflies was tested; on the body surface, the virus could survive up to 24 h and up to 96 h in internal tissues. It indicates that the houseflies could be a mechanical vector of the avian influenza virus (Salamatian et al. 2020).

Recently, the potential of house flies to mechanically transmit SARS-CoV-2 was investigated, and the results indicate, under laboratory conditions, the SARS-CoV-2 can live in house flies for up to 24 h. They showed that house flies could mechanically transmit SARS-CoV-2 genomic RNA to the environment for up to 24 h (Balaraman et al. 2021b).

Another study on field-collected house flies in Shiraz demonstrates that collected flies from Corona Treatment Centers are infected with the virus and can spread the virus in the environment (Soltani et al. 2021).

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).

Conclusion

Cockroaches are among the most prevalent insects globally, and they are cosmopolitan; due to their gregarious nature and synanthropic preferences, cockroaches are commonly found in or near human dwellings. They are also indiscriminate feeders that disseminate microbial pathogens from waste-contaminated breeding habitats to human foods, which human hosts may ingest.

The SARS-CoV-2 contamination causes intense gastrointestinal infection in a few people, and the virus is detected in their feces. The viability of the virus has been reported for up to 72 h on some surfaces and feces and urine. Feces can be considered an essential source of SARS-COV-2 infection.

Therefore, all organisms that contact it or eat it could be associated with SARS-CoV-2 transmission. Thus, the role of insects such as houseflies and cockroaches in SARS-CoV-2 infections could be essential (Fig. 3).

It seems that the virus can live on cockroaches because of their habitat condition. They usually live in highly humid places. The role of these insects in the spread of SARS-CoV-2 will be more important in crowded places such as hotels, lodging houses, restaurants, and hospitals.

To mechanically transmit the virus, cockroaches must first obtain the virus from the contaminated source, ingest a sufficient amount of the virus, and colonize it on the crop, gut, or body surface. Each virus needs to be stable and viable during this period. Overall, this study has shown that cockroaches can acquire, and contaminate the SARS-CoV-2 virus in the environment.

Transmission of the virus by cockroaches can make the epidemiology of the disease very difficult; therefore, the role of vector control, along with methods of prevention and control of other diseases, becomes essential. Healthcare professionals plan and implement Integrated Vector Management (IVM) programs in high-risk areas during the warmer months of temperate regions and every month of the year in tropical areas where the population and activity of these insects increase. Further in vivo laboratory and field studies are needed to investigate the exact role these insects play in the circulation of this deadly universal virus.

The presence of Covid-19 in cockroaches can be very important, opening new frontiers to investigate the environmental diffusion of air, particulate matter, water and sewers as it is reported from other insects such as honey bees and house flies. Monitoring the presence of the SARS-COV-2 virus in insects can help the determination of the epidemiological extent of the disease in the community.

reference link :

Kalantari, M., Vahedi, M., Azizi, K. et al. First molecular detection of SARS-CoV-2 virus in cockroaches. Biologia (2023). https://doi.org/10.1007/s11756-023-01332-7