The American Journal of Tropical Medicine and Hygiene - Volume s1-27, Issue 2, March 1947

Attempts to produce immunity against malaria in birds by the injection of killed malaria parasites have almost always failed. Gingrich (1) and Jacobs (2) however obtained results suggesting that protection against malarial infection in birds can be produced. Gingrich using P. cathemerium in canaries injected excessive numbers of heat or formalin killed parasites intravenously and challenged the birds two days after vaccination. Although evidence of protection was obtained, such a procedure could have little or no practical application. Jacobs employing P. lophurae in white Pekin ducks combined killed parasites with staphylococcus toxoid and used this preparation as a vaccine. Four of six ducks injected with this vaccine appeared to be protected as compared with non-vaccinated control ducks. Two ducks showed little if any protection, one died with high parasitemia whereas the other survived after high parasitemia. The birds were challenged in this experiment on the third day after the last of five injections of vaccine.

Multiple infection of red blood corpuscles is of common occurrence, particularly in heavy infections. It is much more common in malignant tertian than in benign tertian infections, while in the case of quarten infections it is very rare. Binary fission of the malaria plasmodia during their early development within the red blood cells has been recently offered as an explanation for the phenomenon of multiple infections.

Though binary fission is the normal method of reproduction in certain protozoa, spore-formation in schizogony has always been considered as the normal method of reproduction in the asexual phase of malaria plasmodia. A characteristic of reproduction is that it takes place in maturity and not in infancy, whether it is by equal division, unequal division or multiple division. Writing about reproduction of a cell, Calkins observes: “Ultimately its possibilities of further vitality as a single individual are exhausted and it undergoes its final manifestation of vitality.

According to the literature the American negro possesses a marked tolerance, either natural or acquired, to the vivax malaria which he encounters in the United States.

A group of American white and negro troops, stationed in a highly malarious area of the Pacific, were studied to determine their comparative response to Pacific vivax malaria. There was no difference in the incidence of primary or recurrent malaria between the two races. Clinical and epidemiological observations likewise indicated a similar behavior in regard to this disease. Natives of this area in comparison with American negroes and whites manifested definite tolerance to the vivax malaria of their neighborhood.

It is concluded that:

• a.  The American negro lacks racial tolerance to the strain or strains of vivax malaria encountered in the Pacific.
• b.  The susceptibility of American negroes to Pacific vivax malaria does not differ from that of the American white.

• 1.  Fuadin was employed in the treatment of 150 Puerto Rican soldiers harboring Schistosoma mansoni ova in their stools. The patients studied were considered to have mild or moderately severe chronic infections.
• 2.  No cases of schistosomiasis mansoni were encountered in North American troops stationed in Puerto Rico.
• 3.  Fifty-five or 37 per cent of the individuals treated were asymptomatic prior to treatment. In 60 cases, or 40 per cent, the finding of schistosome ova in the stools was incidental to the condition for which the patient was hospitalized.
• 4.  The frequency of various signs and symptoms encountered in ninety-five cases are presented.
• 5.  The drug was given in courses of 45 cc. each, comprising a total of 10 intramuscular injections. The first 3 injections of 1.5, 3.5, and 5 cc. each, were given on successive days and the remaining 7 injections on alternate days. One hundred and fifty cases received 1 course of fuadin; twenty-one cases were given a second course (90 cc.) of therapy and fifteen others received 3 to 6 courses (135 to 270 cc.).
• 6.  Toxic reactions of a mild degree occurred in 30 or 20 per cent of the cases. Two patients developed constitutional reactions.
• 7.  The immediate effect of therapy was as follows: 114 cases or 76 per cent had negative stools after 1 course, and an additional 10 per cent following a second course.
• 8.  Follow-up observations for a period of 1 to 24 months after treatment in 70 unselected cases revealed 39 individuals (56 per cent) with positive stools for schistosome ova and 31 (44 per cent) with no ova in the stools.
• 9.  Fuadin, when given in 1 or 2 courses (45 or 90 cc.), is not a very efficient drug in the treatment of mild, asymptomatic, or moderately severe chronic infections with Schistosoma mansoni, as determined by the presence of ova in the stools.

• 1.  Parasitologic findings on 400 soldiers are presented. These men were prisoners of the Japanese and interned in the Philippines and Japan.
• 2.  Eighty-six per cent were found to harbor intestinal parasites, while 76 per cent harbored parasites generally considered to be pathogenic.

Agglutination of the cysts of E. histolytica obtained from culture occurs in dilutions of the blood serum of man and of the horse. Judging from the few cases studied, there appears to be no correlation of this agglutination phenomenon with either infection with E. histolytica or complement fixing properties of a serum. Further investigation of the problem seems indicated.

• a.  In town of “S” after application by airplane of 5632 pounds of DDT in Diesel oil over a four month's period, there was no evidence of a lowered incidence of malaria among the residents as measured by splenic or blood positive cases. In fact, incidence of parasite positives, April 1946, increased practically 100 per cent over the incidence of April 1945 and was considerably higher than the comparison town of “N.C.”
• b.  In town of “L”, the boxes sprayed with 5 per cent DDT in kerosene and after “weathering” gave evidence of a lethal capacity for mosquitoes introduced into them and forced to rest on the sprayed walls. This lethal capacity reached 100 per cent mortality for mosquitoes confined in the boxes for five hours 129 days after having been sprayed. (The evidence of malaria, however, as measured by splenic and blood positives shows practically no alteration when compared with the comparison town or compared with the survey of 1945 performed in the same town.)
• c.  The town of “P” has shown a marked drop in malaria incidence as measured by blood findings both when compared with the comparison town and compared with its own survey performed in April last year.
• d.  The comparison town where no control was performed showed blood and splenic positive cases practically the same in April 1946 as in April 1945.

• 1.  SN 8557, a 2-[3-(decahydro-2-naphthyl)propyl]-3-hydroxy-1,4-naphthoquinone, in doses of 150 mg./Kg.-day for 5, 10 or 15 days cured 61 of 110 canaries with various types of Plasmodium cathemerium infections. Administration of the drug for 15 days cured 28 of 36 birds (78 per cent) including some with latent sporozoite induced infections.
• 2.  Acute infections of the exclusively erythrocytic strain 3H2-1 are more susceptible to cure than the 3C strain in which both erythrocytic and exoerythrocytic development occur. In latent infections, susceptibility to cure appears to be related to the duration of latency as well as to the strain.
• 3.  A schedule of short term treatment (4 to 5 days) begun the day of inoculation (0.5 × 106 erythrocytic parasites intravenously) with strain 3H2-1 is a fair indicator for curative effect in latent infections, whether blood or sporozoite induced, or of a more virulent strain.
• 4.  The duration of an efficient immunity to P. cathemerium in canaries is less than 5 months following cure.

• (1)  The pathogenesis of amebiasis is discussed.
• (2)  Comparative amebacidal tests in vitro and in vivo have been made, utilizing improved appraisal technics.
• (3)  The development of an essentially synthetic medium may lead to a more rational approach to the chemotherapy of this disease.
• (4)  The mechanisms of anti-amebic action have been demonstrated for two of the various chemical types available.
• (5)  Three trivalent arsenicals (two containing sulfur) have proved of value in trials in macaques, and one has been effective in initial trials in man.

It was found that 58 per cent of C. laniger injected with 1,000 LD50 of yellow fever virus circulated virus following the inoculation. The virus content of the serum of the infected animals was found to be small in most instances, the majority of titers being less than 1/100. The susceptibility of some of the animals was shown to depend on the amount of virus inoculated.

Over 90 per cent of the animals circulating virus developed neutralizing antibodies. Frequently these antibodies were present in small amounts, and their detection was possible only in neutralization tests employing small test doses. However, since no evidence of non-specific viricidal activity was found in normal woolly opossum sera, it was considered that a survival ratio of 2/6 or greater indicated the presence in the serum of neutralizing antibodies. Studies on the persistence of neutralizing antibodies in the serum revealed that a significant number of animals lost these antibodies during the course of a year after inoculation.

Reinoculation of previously infected animals with large doses of yellow fever virus showed that occasionally animals would completely lose their immunity and circulate virus following the second dose of virus. In some cases it was found that although the animal had lost detectable humoral immunity, no virus could be isolated from the blood, which demonstrated that the intracerebral neutralization test result is not always a reliable indication of the immune status of the animal. Animals with neutralizing antibody at the time of inoculation in no instance circulated virus, thus establishing the specificity of the neutralization test.

The epidemiological implications of the data are discussed.

In 1944 and 1945 a 5 per cent DDT-kerosene spray was applied to the walls and ceilings of all buildings in specified areas of the Bonifica di Castel Volturno on the Italian coast just north of Naples. Results in 1944 were so promising that in 1945 a more extensive project was launched in an area of approximately 120 square miles in the Tiber Delta, where a 6.5 per cent solution of DDT in kerosene was applied once at a rate of approximately 200 milligrams per square foot to the interiors of all human habitations and animal shelters between February 27 and June 15. The objective was to determine the residual effect of the spray upon anopheline density in the absence of other control measures.

The organization of the field staff, the preparation of the insecticide and the equipment and methods employed in its application are described.

Routine searches for A. labranchiae adults and larvae in Castel Volturno and in the Tiber Delta indicated that density had been greatly reduced. A year after treatment no anopheles were found in previously sprayed buildings examined in the Delta.

In Castel Volturno a significant reduction in the parasite rate of school children occurred during the 16-month period of observation. While malaria morbidity in the Delta in 1945 was higher than in prewar years, its distribution by months showed a rapid rise to a peak in March and a continuous drop thereafter, indicating that most, if not all, of the cases reported came from infections of the previous year. The usual summer rise in incidence failed to appear.

In this beautifully printed and illustrated volume the authors have furnished public health workers and physicians a work which embodies their personal experience in malariology and the results obtained by others, in a practical manner. As stated in the Preface: “It is designed to give clinical, laboratory, and field information about malaria, capable of being put to use in daily practice. The design of the book is not enclycopedic or bibliographic, nor is it synoptic.” This statement should be borne in mind in a consideration of the work from a critical standpoint, for while the subject of symptomatology, and the clinical aspects of malaria, are adequately considered, the practitioner of medicine will not find in this work an encyclopedic discussion of this phase of the subject. It is essentially a work devoted to the diagnosis and prevention of malarial infections and hence of very special value to the public health worker in malarious localities.

The following points are based upon microfilarial counts of the blood of two patients parasitized with Wuchereria bancrofti.

• 1.  Microfilariae were present at all hours of the day and night regardless of whether or not the parasitized individuals were awake or asleep.
• 2.  In these two cases peak counts over 26 hour periods were diurnal, the peaks occurring between noon and 8:00 p.m.
• 3.  Conversely, the lowest densities were nocturnal, occurring between midnight and 8:00 a.m.
• 4.  The ratio of the mean high and low daily counts in both patients was low, being 3.4 in the case of patient A and 2.3 in the case of patient B.
• 5.  In patient A the count over a seven and one-half month period showed some increase in numbers of microfilarise in spite of drug therapy with stibanose.
• 6.  In patient B the peak density occurred 11 months after microfilariae were first demonstrated in the patient's blood. Three months and a half later the count showed a decrease, although the patient received no therapy.
• 7.  It is suggested that the term “diurnal periodicity” might be found to be more appropriate than the terms “non-periodic” or “aperiodic” which appear widely in the literature.

Susceptibility experiments with a strain of Wuchereria bancrofti (Cobbold) from Bora Bora in the Society Islands showed that development to advanced or infective stages occurred in the following United States mosquitoes: Culex pipiens, C. quinquefasciatus, C. erraticus, C. salinarius, Anopheles walkeri, A. punctipennis, Aedes triseriatus, A. aegypti, A. atropalpus, and Mansonia perturbans. Taking into consideration the habits and prevalence of the species, it was concluded that only Culex pipiens (83.5 per cent infected) and possibly Culex quinquefasciatus (34.9 per cent infected) were sufficiently susceptible to be dangerous potential vectors.

Anopheles quadrimaculatus, A. freeborni, Aedes atlanticus (or tormentor), and Psorophora ferox failed to develop the infection beyond the early first larval stage.

The incidence of scrub typhus in three groups of troops operating in an area where one of the probable vectors of this disease was found and where various degrees of protection against the mite was used has been analyzed. Troops with no protection had the highest incidence of the disease, as compared with a lower incidence in troops where clothes were sprayed with dimethylphthalate, and lowest in the group whose clothes had been actually impregnated with a 5 per cent emulsion of dimethylphthalate. There were no instances of dermatitis.

It is considered that this experience offers evidence indicative of the high degree of protection against scrub typhus provided by clothes impregnated with dimethylphthalate.

Four outbreaks of shigellosis recently occurred aboard a Naval vessel (1). Several shigella carriers were found who were considered to be the source of infection in the last two outbreaks. A study of these carriers (with particular reference to their therapy) was undertaken since they constituted a major problem in eradication of the disease.

It is obvious that a large number of persistent shigella carriers can be an epidemiological problem. Manson-Bahr (2) reports an individual who excreted dysentery bacilli for a period of three years. In an excellent review, Neter (3) states that carrier rate surveys have varied from 3–80 per cent and that 3 per cent of convalescent carriers excrete organisms for more than three months after the onset of the disease. Watt et al. (4) studied 57 cases of Shigella flexneri infections. Among this group 45 individuals (79 per cent) became convalescent carriers, in 38 of whom the duration of the carrier state was determined.

By means of the Saisawa-Sugawara silver deposition method it was demonstrated that the commoner blood and tissue microfilariae possess annular transverse cuticular striations that completely cover the embryos from tip to tip.

Striated cuticulae were demonstrated on the Mf. of Wuchereria bancrofti, W. malayi, Loa loa, Mansonella ozzardi, Acanthocheilonema perstans, Onchocerca volvulus, Dirofilaria immitis and, with less certainty, on Litomosoides carinii.

No embryo of the 8 species examined possessed a lateral or side line. These alleged lines, and the knobby ends of the striations, were demonstrated to be optical artifacts.