Armstrong – Table of Contents

1924, Drs. R. R. Parker, R. R. Spencer with Francis, working at the Rocky Mountain
Laboratory, reported that wood ticks (Dermacentor andersoni) in the Bitterroot Valley,
Montana were naturally infected and were able to transmit the disease (19). Subsequent
studies have shown that the organism is widespread in other world areas of the Northern
Hemisphere and is carried by many rodent species, especially rabbits and squirrels.
Humans most frequently acquire tularemia after contact with the tissues or body fluid of
an infected mammal (e.g. a hunter skinning an infected rabbit with his bare hands) or
from the bite of an infected arthropod (e.g. ticks, deer flies, mosquitoes).
The organism is a small, gram-negative, non-motile coccobacillus, tending to be
pleomorphic in culture and difficult to culture because of fastidious nutritional growth
requirements. Tularemia may occur in several clinical presentations; e.g. an ulcer on a
hand with a painful lymph gland in the arm pit or elbow; a general enlargement of lymph
glands not accompanied by ulcers; inflammation of an eye from rubbing with an infected
hand; or a non-localizing febrile illness. Pneumonia may accompany any of these clinical
features of tularemia, is often the most debilitating manifestation and carries a high
mortality. Excellent clinical and microbiological descriptions of tularemia can be found
in recent texts (20).
The mystery remains about how Armstrong may have been exposed to tularemia.
He was unaware of possible sources of infection. There was no current work on this
organism at the Division in Bethesda (21) since all investigations of low priority projects
that were unrelated to the war effort had been suspended temporarily. There was no
current work on tularemia at the Rocky Mountain Laboratory but cultures were
maintained on the premises. Armstrong, however, had no exposure to these cultures.