12 Tue BLOWFLIES oF NortH AMERICA 
the surface or within the bodies of blowflies collected in the field 
during epidemics of the disease. No less than three groups of 
investigators made such recoveries from adult blowflies in 1941 
and 1942. Sabin and Ward (1941-1942) found the virus to exist 
in 8 of 15 samples of blowflies captured in the vicinity of out- 
breaks of the disease in Georgia and Ohio. Trask et al (1940- | 
1948) and Paul et al (1940-1943) found the virus to occur in 
4 of 19 samples of blowflies collected within epidemic areas 
during and after the onset of nearby cases of poliomyelitis in 
Connecticut, Alabama, and eastern Canada. All of these positive 
samples contained specimens of Phaenicia serrcata and Phormia 
regina. Some of the samples contained specimens of Proto- 
phormia terrae-novae as well as a few specimens of less abundant 
species. These species are not frequent visitors to human excre- 
ment, especially that in outdoor deep pit latrines. Where and 
how they originally obtained the virus is still an unsolved prob- 
lem. Whether the virus multiplies on or within the bodies of 
blowflies or is merely carried accidently is unknown. It is doubt- 
ful that they obtain the infection from the excrement of persons 
ill with poliomyelitis; houseflies in the same or in similar samples 
were not positive for the virus. It is possible that animal reser- 
voirs of such diseases occur in nature. Animals die and normally 
become infected with blowfly larvae. Larvae and adults from 
infected animals would probably be positive for the virus. The 
promiscuous and omnivorous feeding habits of blowflies together 
with their habits of regurgitation and defecation on human 
foods would make the transmission of the virus to humans 
possible and a relatively simple matter. Anyone visiting markets 
can observe great numbers of these species feeding or congre- 
gating upon fruits such as peaches, grapes, and others, all of 
which are commonly consumed unwashed by humans. These 
factors in the origin and transmission of this disease have not 
been investigated. © 
Non-enteric Diseases. Larvae, pupae, and adults of blowflies 
reared from carcasses of rats which died of plague (Pasteurella 
pestis) were all positive for that organism according to Russo 
(1931). He found plague bacilli in the excrement of such flies. 
Larvae of blowflies fed upon meat infected with spores of anthrax 
(Bacillus anthracis) remained infective for that organism for 
several days after adults had emerged from their pupal cases 
according to Graham-Smith (1911). He cultivated the bacillus 
from the appendages and intestinal contents of the reared flies 
for more than 15 days after emergence as adults and these flies 
were found to be capable of infecting materials over which they 
