The American Journal of Tropical Medicine and Hygiene - Volume s1-15, Issue 4, July 1935

It is most fitting that the address of your Acting President at the first annual meeting of the American Academy of Tropical Medicine should take the form of a memorial to the Academy's first President, the late Doctor Theobald Smith.

Forty-six years ago there appeared a paper by Theobald Smith in the December, 1889, issue of the Medical News of Philadelphia. In this paper the author described an organism present in the red blood corpuscles of cattle suffering from Texas fever, which he had demonstrated to be the cause of the disease. This organism he considered to belong to the Protozoa and named it Pyrosoma bigemina, a name now changed because of nomenclatural rules to Babesia bigemina. Four years later, after exhaustive studies of the etiology and epidemiology of Texas fever, Smith and Kilborne published the results of these researches in Bulletin No. 1, U. S. Department of Agriculture, 1893.

The anti-serums for these initial therapeutic trials were produced from goats after subcutaneous inoculations with chemically treated suspensions of Brucellae. The serums used during the first year represented 6 strains, one bovine and 5 porcine. These types were identified for us through the courtesy of Dr. Huddleson. At the beginning of the second year 5 melitensis strains were added to these six. One animal received formaldehyde-killed bacteria only; the other was inoculated with formaldehyde-killed suspensions that had subsequently been treated with nascent nitrous acid, a procedure which further “detoxifies” these bacteria and probably largely deaminizes their component proteins (1). These serums, so far as we are able to judge now, are equally effective therapeutically. The principle involved, and details of production, will be presented at some future time.

We have had to feel our way in regard to dosage. During the past year we have adopted a total amount of 60.0 cc., usually given in 3 daily injections of 20.0 cc. each, as the average adult dosage for infections of average severity.

The study of natural immunity and susceptibility of mosquitoes to malaria, as well as of the other arthropods to the parasites which they transmit is of great importance. Susceptibility to a given parasite in one species of arthropod may be the absolute determining factor in making this species a highly efficient vector. On the other hand other species of arthropods may possess a natural immunity to the parasite and will therefore take no part in its transmission although, except for this natural immunity, they may appear to be equally well adapted to serve as vectors. Our malaria problems would have been much simplified—and I probably should not be talking to you today—if it had been shown that the transmission of malaria was sharply restricted to a few species of mosquitoes. Unfortunately it has been found that susceptibility to malaria parasites is not strictly correlated with any species, variety, or race of mosquitoes.

Ornithodorus Hermsi Wheeler, New SpeciesFemale. Ovoid, conically pointed anteriorly, anterior dorsal portion of the hood visible from above, broadly rounded posteriorly; unengorged specimens a light sandy color with the black of the intestinal diverticulae visible through the integument of the dorsal surface; freshly engorged specimens a dull, deep garnet shade with a greyish sheen over body, anterior conical point whitish. The color changes to a greyish-blue a few days after feeding. Legs and hood pale yellow. In newly molted forms the body and legs lighter but gradually assume the light sandy appearance and the legs darken correspondingly. In preserved unengorged specimens the color deepens to a reddish-brown.

Hood. Curved ventrally, projecting over the mouth parts and palpi, the rounded point and ventral surface with many long hairs between the mammillae.

Capitulum. Located in a deep camerostome with rounded integumental folds along the lateral and posterior margins, ventral surface finely and transversely wrinkled.

The trophozoites of E. histolytica, E. coli and E. nana and of Dientamoebae fragilis have been observed in aqueous smears and the essential findings recorded. Material for a similar study of the trophozoites of Iodamoeba butschlii has not been available. The observations indicate that certain features in the morphology of the amoebae can be demonstrated in the aqueous medium, such as (1) the distensibility of the ectoplasm of the E. histolytica, (2) the relative fragility of the ectoplasm of the E. coli and E. nana, (3) the resiliency of the ectoplasm of the Dientamoeba fragilis, (4) the remarkable strength of the nuclear membrane of the E. histolytica and E. coli.

Some of these characteristics together with the visibility of the nuclei help to differentiate the species of amoebae in the human stool.

It also has been recorded that the annoyance of Blastocystis hominis can be eliminated by the use of the aqueous smear.

I have been unable to find any reference in the literature to the use of aqueous smears in the study of the amoebae of man. However, it does not seem possible that such a simple procedure has not been used by some workers.

It is my pleasure to acknowledge the generous and valuable advice of Dr. C. M. Johnson, protozoölogist at the Gorgas Memorial Laboratory and the efficient assistance of J. F. Buckner and H. A. Down of the Hospital Corps, U. S. Navy.

The public health profession is rapidly reawakening to the importance of plumbing in the prevention of disease, as the result of the country-wide outbreak of amebic dysentery in 1933, which had a focus in two hotels in Chicago.

Efforts to stop the outbreak were, at first, directed toward the control of carriers, particularly among food handlers, in keeping with the then generally accepted belief that they were the principal, if not the only, means of spread. After these measures were found to be insufficient, a very careful study of the plumbing was made in the hotels involved, and it became clear that contamination of water through bad plumbing was the chief cause of the outbreak.

Correction of the hazards in the plumbing systems in the hotels was followed by the complete subsidence of the outbreak among the guests.

Regulation of plumbing was first begun as a health measure before the time of Pasteur.

Torula histolytica recovered from a human case in which there was a local involvement of the knee joint together with the subsequent occurrence of lesions in the region of the nipples has been studied in culture and by inoculation into certain laboratory animals.

This strain is similar to other strains recovered from cases showing brain and spinal cord lesions, both in regards to its morphologic characteristics and its fermentation reactions.

Rats and mice became infected easily upon intraperitoneal inoculation but three guinea pigs and three rabbits inoculated resisted infection.

Two monkeys inoculated intracardially developed unusually small nodular cutaneous lesions on the face, eyelids and ears from which torulae were recovered. One of the monkeys developed a generalized torulosis involving the brain and spinal cord while the second monkey recovered in four months. Other monkeys inoculated by the same route with strains of torula obtained from human nervous tissue developed lesions of the brain and cord but failed to show cutaneous lesions.

These observations raise certain questions with reference to tissue selectivity of different strains of torula and also with reference to spontaneous recovery from torula infection.

The susceptibility of anopheline mosquitoes to malaria parasites has both a qualitative aspect (1). Qualitatively, susceptibility is revealed as the proportion of the mosquitoes which become infected after feeding on an infectious patient. Quantitatively it is shown by the numbers of cysts developing on the stomachs of the mosquitoes which become infected.

We have already (2) called attention to the fact that A. crucians is not as effective a host to any of the three commonly recognized species of human malaria parasites as is A. quadrimaculatus. We are at present making a similar comparison of A. quadrimaculatus and A. punctipennis. It is therefore a matter of interest to scan the data available in order to ascertain if possible, whether A. quadrimaculatus itself is equally susceptible to different species of plasmodia.

The observations discussed were made in the course of our routine propagation of parasites for purposes of malaria therapy.