Experimental Evaluation ofMusca domestica(Diptera: Muscidae) as a Vector of Newcastle Disease Virus

Abstract

House flies, Musca domestica L. (Diptera: Muscidae), were examined for their ability to harbor and transmit Newcastle disease virus (family Paramyxoviridae, genus Avulavirus, NDV) by using a mesogenic NDV strain. Laboratory-reared flies were experimentally exposed to NDV (Roakin strain) by allowing flies to imbibe an inoculum consisting of chicken embryo-propagated virus. NDV was detected in dissected crops and intestinal tissues from exposed flies for up to 96 and 24 h postexposure, respectively; no virus was detected in crops and intestines of sham-exposed flies. The potential of the house fly to directly transmit NDV to live chickens was examined by placing 14-d-old chickens in contact with NDV-exposed house flies 2 h after flies consumed NDV inoculum. NDV-exposed house flies contained approximately 10(4) 50% infectious doses (ID50) per fly, but no transmission of NDV was observed in chickens placed in contact with exposed flies at densities as high as 25 flies per bird. Subsequent dose-response studies demonstrated that oral exposure, the most likely route for fly-to-chicken transmission, required an NDV (Roakin) dose > or =10(6) ID50. These results indicate that house flies are capable of harboring NDV (Roakin) but that they are poor vectors of the virus because they carry an insufficient virus titer to cause infection.

Mechanical transmission of SARS-CoV-2 by house flies

“…The swab samples collected from transfer containers contained a maximal CN of 10 5 SARS-CoV-2 RNA/µl, indicating that house flies carry RNA amounts which are on the borderline for containing infectious virus to be detected in our VI assay. A similar observation was made in an another study involving house fly transmission of Newcastle disease virus [ 16 ], where house flies harbored an insufficient amount of virus to transmit the pathogen.…”

“…wings, legs, mouthparts) and internally in their alimentary canal [ 13 , 14 ]. Moreover, house flies have been demonstrated to transmit coronaviruses, namely the turkey coronavirus (TCV) [ 15 ], and other important viral agents, including Newcastle disease virus [ 16 ], porcine respiratory syndrome virus [ 17 ] and porcine transmissible gastroenteritis [ 18 ]. However, the potential for house flies to acquire, harbor and transmit SARS-CoV-2 has not been investigated yet.…”

Zoonotic and Reverse Zoonotic Transmissibility of SARS-CoV-2

“…The prediction of possible hosts suggests that SARS-CoV-2 could indeed infect a broad range of mammals, and thereby more high-quality epidemiological surveillance studies are much needed. Furthermore, the need for more in-depth research has also increased due to the current lack of studies assessing the mechanical transmission of SARS-CoV-2 by rodents, insects, and arachnids, which have been already recognized as a mechanical vector of over 100 pathogens including bacteria, fungi, virus, and parasites ( El-Sherbini and Gneidy, 2012 ; Foil and Gorham, 2000 ; Gough and Jorgenson, 1983 ; Graczyk et al, 2005 ; Issa, 2019 ; Nayduch and Burrus, 2017 ; Onwugamba et al, 2018 ; Pitkin et al, 2009 ; Watson et al, 2007 ). Although SARS-CoV and other related coronaviruses have been reported to be mechanically transmitted by pests, together with SARS-CoV-2’s survivability on surfaces and in feces for elongated periods would undoubtedly implicate them as culprits in the role of its transmission.…”

Escherichia Coli Transfer to Food by Fruit Flies during Short Time Exposure

“…Pathogenic viruses (Calibeo-Hayes et al, 2003;Chakrabarti et al, 2008;Otake et al, 2004;Schurrer et al, 2005;Watson et al, 2007) bacteria (Ahmad et al, 2011;Doud et al, 2014;Fleming et al, 2014;Goush et al, 2014;Soheyliniya and Barin, 2014;Wei et al, 2014) and parasites (Balla et al, 2014;Graczyk et al, 2005;Szostakowska et al, 2004) have been found on flies. Antibiotic-resistant bacteria were also isolated from flies (Ahmad et al, 2011;Wei et al, 2014).…”