"2. That in practically all cases of this disease it can be shown that the patient has been bitten by a tick.
"3. That the period between the tick bite and the onset of the disease in the many animals he has experimented with corresponds very closely to this period as observed in man.
"4. That infected ticks are to be found in the locality where the disease occurs.
"5. That the virus of spotted fever is very intimately associated with the tissues of the tick's body as is shown by the fact that the female passes the infection on to her young through her eggs, and further, by the observation that in either of the two earlier stages of the life cycle the disease may be contracted by biting a sick animal and communicated to other animals after molting or even after passing through an intermediate stage."
Professor R.A. Cooley of Montana, from whose report the above quotation is taken, has also made studies of the habits of the tick and believes there can be no doubt that it is the disseminator of the disease.
Relapsing Fever. The relapsing fever is an infectious disease or possibly a group of closely related infectious diseases occurring in various parts of the world. Occasionally it is introduced into America, but it does not seem to spread here. It has been shown that the disease is communicated from one person to another by means of blood-sucking insects. In Central Africa where the disease is very prevalent a certain common tick (Ornithodoros moubata) ([Fig. 18]) is known to transmit the disease. This tick lives in the resting places and around the huts of the natives and has habits very similar to the bedbug of other climes, feeding at night and hiding during the day. It attacks both man and beast and is one of the most dreaded of all the African pests.
Nathan Bank, our foremost authority on ticks, in summing up the evidence against them says:
"It is therefore evident that all ticks are potentially dangerous. Any tick now commonly infesting some wild animal, may, as its natural host becomes more uncommon, attach itself to some domestic animal. Since most of the hosts of ticks have some blood-parasites, the ticks by changing the host may transplant the blood-parasites into the new host producing, under suitable conditions, some disease. Numerous investigators throughout the world are studying this phase of tick-life, and many discoveries will doubtless signalize the coming years."
MITES