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The Rat Mite Attacking Man. 8 
and hiding places and that they detach themselves and remain in 
such situations. When hungry, however, the mites crawl about freely 
during day and night in search of food. It was thought at first that 
the scattering of the hungry mites might be due to the destruction 
of their normal hosts, the rats, but later observations did not sub- 
stantiate this, as mites were found in great numbers where the rats 
were abundant and had not been disturbed. It is possible that there 
might be associated with this a scarcity of young in the nests or a 
movement of the rats to other nesting quarters, thus driving the 
mites to seek food. 
From observations in infested premises and a few cage experiments 
it appears that the mites are not very long lived in any stage when no. 
food is available. In confinement, apart from a host, the greatest 
longevity noted was 10 days, but it seems to be greater when the mites 
are allowed to remain in their natural environment in a building. 
In many instances mites have been observed to drop from the in- 
fested ceiling of a room. They have been found also to pass from 
one floor of a building to another along pipes extending through 
the floor. 
CHARACTER OF ATTACK ON MAN. 
Both the nymphs and adults attack man freely. The pale unfed 
nymphs usually appear in greatest numbers and are thought by some 
to bite much more frequently than the adults. All crawl rather 
actively and frequently do much running about over the body, biting 
here and there. Some annoy by crawling about without biting, 
especially on the hands and arms. 
No particular region of the body is chosen by the mites to the ex- 
clusion of others, although they seem to prefer tender skin. The 
upper arms and legs apparently suffer most, but bites occur on all 
parts of the body. There is some tendency to bite where there is 
- some constriction of the clothing, as around the belt. 
The bite is distinctly painful at the time the mouth parts are 
inserted. A sharp itching pain is usually experienced. The dura- 
tion of the pain from the bite varies with the individual. There is 
also much variation among individuals as regards frequency of | 
bites, their after effects, and the géneral annoyance produced by 
the presence of mites. Some claim to have been made ill through 
the attack of many mites, and to have had some fever and a feeling 
of general discomfort. This is probably due to the nervous condition 
of the victim and revulsion of feeling toward the pest. 
Usually there is more or less irritation and itching at the site 
of attack for several hours along with the development of a small 
hemorrhagic area. These red spots seldom persist more than two 
days. 
No specific disease has been connected with these parasites. 
SUGGESTIONS FOR CONTROL. 
The repression of this mite appears to be essentially a problem in 
rat control.2, Our experience in Texas indicates that where rats are 
?For full information regarding the control of rats the reader is referred to Farmers’ 
Bulletin 1302, How to Get Rid of Rats, which may be obtained free on application to 
the Department of Agriculture. 
