The objectives of the study were to determine the duration of porcine reproductive and respiratory syndrome virus (PRRSV) survival in houseflies (Musca domestica Linnaeus) following feeding on an infected pig, and to determine whether the virus was present on the exterior surface or within the internal viscera of the fly. A total of 210 laboratory-colonized houseflies were allowed to feed to repletion on a pig, experimentally infected with PRRSV on day 7 postinoculation, and then maintained alive under laboratory conditions (27°C). Two subsets (A and B) of 30 flies were collected at each of the following sampling points; 0, 6, and 12 hours post feeding (pf). Subset A contained an extra group of 30 flies collected at 24 hours pf due to the availability of extra flies. Flies in subset A were processed as whole fly homogenates, while the exterior surface washes and digestive organs were collected from flies in subset B. Whole fly homogenates, collected at 0, 6, and 12 hours pf, were positive by both polymerase chain reaction (PCR) and swine bioassay. Digestive organs, collected at 0 and 12 hours pf, were positive by PCR and swine bioassay. The PRRSV RNA was detected by PCR from the exterior surface wash of subset B flies collected at 0, 6, and 12 hours pf; however, only the subset collected at 0 hour pf was swine bioassay-positive. This study indicates that infectious PRRSV can survive within the intestinal tract of houseflies for up to 12 hours following feeding on an infected pig, but only for a short period on the exterior surface of the flies.

In laboratory experiments, pseudorabies virus was readily recovered from within the body of houseflies (Musca domestica L) that had ingested the virus. Age of the fly and ambient temperature affected the rate of virus inactivation within the houseflies. Virus half-life in 3-day-old flies was 6.36 hours vs 2.81 hours in flies 8 or 13 days old. Half-life in 5-day old flies was 12.92 hours at 10 C, 5.95 hours at 20 C, and 2.69 hours at 30 C. Virus half-life in dead flies was 9.06 hours at 10 C, 4.28 hours at 20 C, and 1.71 hours at 30 C. The data did not provide any evidence of virus replication in either living or dead flies.

In this study, we retrieved 42 live third-stage larvae from the crop of an infected squab. This condition is known as myiasis, which occurs due to the infestation of fly larvae belonging to the order Diptera in the tissues. The larvae may affect the storage and digestive functions of the crop in squabs. Here, we report the first case of crop myiasis in a pigeon squab, caused by Musca domestica (Diptera: Muscidae), identified using morphological keys.

Beauveria spp., an entomopathogenic fungus, has recently been widely used as a biocontrol agent of house fly populations to evade the critical effects of chemical insecticides on humans, animals, and the natural ecosystem. In the presented study, different types of fungi were isolated from house flies collected from various locations in different Egyptian governorates between 2021 and 2022. The flies were caught in garbage dumps, dairy and meat production units on cattle farms and poultry farms. The entomopathogenic fungi were identified morphologically and genetically, showing that the isolate was molecularly identified as Beauveria bassiana. This efficacy of the isolated fungal strain against the house fly, M. domestica, was estimated using laboratory bioassay by the immersion method. The isolated fungal strain successfully induced fatal changes with a high mortality rate in the laboratory-reared house flies, which confirms the scientific world researches which has been carried out. The achieved result showed a direct correlation between fungal concentrations and the mortality rate, which reached up to 99.16 %. They also exhibited great destruction and a direct relationship between the increase in spore concentration and the degree of overall DNA genotoxic damage in the exposed fly's DNA to Beauveria bassiana. Beauveria bassiana MN960454.1 can be used as an efficient way for controlling house fly biologically reached up to 99.16 %. Thus, it is recommended to apply Beauveria spp. as a spray in house fly breeding areas.