The American Journal of Tropical Medicine and Hygiene - Volume 7, Issue 6, November 1958

• 1.  The isolation of a strain of Bunyamwera virus from the blood of a naturally infected human being is described.
• 2.  Following infection there was a significant increase in titer of both neutralizing and hemagglutination-inhibiting antibodies in tests controlled by the inactivated acute serum from which the virus was isolated.
• 3.  The significance of Bunyamwera virus as a causative agent of disease in human beings is discussed.
• 4.  Three strains of this virus were isolated from Aedes (Banksinella) circumluteolus mosquitoes and two of these were from insects collected during the same time period and in the same locality where the human case acquired infection.
• 5.  Evidence is discussed which would indicate that this mosquito species is a potential vector of Bunyamwera virus.

• 1)  The serological responses of 29 cases of human yellow fever infection were studied by hemagglutination-inhibition (HI), complement-fixation (CF) and neutralization (N) tests.
• 2)  The cases were divided into two groups, chiefly according to the pattern of CF antibodies to a variety of Group B agents. The 17 cases in the first group are considered to be primary infections of yellow fever; the 12 cases in the second are considered to be infections of yellow fever in individuals who had previously been infected with another Group B virus.
• 3)  In primary infections of yellow fever specific HI antibodies appear first, followed rapidly by antibodies to other Group B viruses. The titers of homologous HI antibodies are always as high as, or higher than, the titers of heterologous antibodies.
• 4)  In primary infections there is great variation in the time after onset at which CF antibodies become demonstrable. Complement-fixing antibodies are produced over a long period and may still be increasing when HI antibodies are diminishing. The pattern of CF antibodies is remarkably specific. Overlaps with other antigens occur only when the homologous CF antibodies are high.
• 5)  In primary infections the development of N antibodies as determined by the standard intracerebral test is quite specific. Heterologous N antibodies are developed to a limited extent.
• 6)  In cases of secondary infection, the production of HI and CF antibodies is both massive and very rapid. There is no suggestion of specificity in the patterns developed and, in fact, as a rule the highest HI and CF antibodies were heterologous. Furthermore, in secondary infections the production of heterologous N antibodies is stimulated to a greater extent than in primary infections. In the present 12 cases, the heterologous response was so great that in all but one of the cases accurate diagnosis of the current illness by N test was impossible.

A simple medium prepared from powdered gastric mucin is described for the cultivation of Entamoeba histolytica.

Excellent growth of two strains of E. histolytica grown with bacterial associates was maintained in this medium.

The first case of sparganosis in Colombia has been found, being the third in South America. This seems to be the first of ocular localization to be reported in the Western Hemisphere. Investigations directed toward finding the adult parasite and larvae of Diphyllobothrium species in several animal hosts were negative.

Two dosage schedules of dithiazanine, 200 mg t.i.d. for 4 days and 300 mg t.i.d. for 3 days were given Mexican farm laborers infected with certain helminths. Post-therapy stool studies revealed apparent cures in all patients infected with five species of helminths, as follows: Twenty-two cases were treated and found negative on subsequent stool examinations for Ascaris lumbricoides; similarly five for Trichuris trichiura; six for Taenia sp.; three for Enterobius vermicularis; and one for Strongyloides stercoralis. Results on other infections treated are: Ten of 23 cases with Hymenolepis nana and three of 16 hookworm infections remained negative for eggs.

The results of the study, based on active out-patients treated with dithiazanine, agree with those of others indicating quite effective therapeutic results obtained in treating trichuriasis and strongyloidiasis, as well as ascariasis and enterobiasis. The drug is less effective against hookworm infection. Of additional interest is the report of apparent drug activity against two tapeworms, H. nana and Taenia sp., findings not previously reported. In 10 of 23 (43.5%) of the H. nana-positive cases treated, the stools remained negative for eggs of this worm. All six of the cases of taeniasis remained negative for the duration of the test period.

Urine was examined before and after treatment in 13 cases and no significant changes were noted; likewise, blood hemoglobin and differential counts were made on the same cases, the findings indicating no significant change after use of the drug. Of 73 treated cases, 32.8 per cent reported some nausea and 24.7 per cent vomiting during the course of treatment. All but one patient, reporting nausea, completed his course of treatment. This patient was convalescing from hepatitis. One patient could tolerate only 100 mg t.i.d. but took a total of 2,400 mg with an apparent cure of his hookworm infection. The observations on drug side effects were complicated by a simultaneous outbreak of food poisoning, with vomiting and diarrhea, in some of the study group.

Five raccoons trapped at Patuxent Research Refuge, Laurel, Maryland, were found to have trypanosomes in the blood which were morphologically indistinguishable from Trypanosoma cruzi on stained smears. The organism grew well in culture. It developed and reproduced in Triatoma protracta, T. infestans, T. phyllosoma, and Rhodnius prolixus. Experimental infections were produced in raccoons, opossums, mice, rats, and monkeys by inoculation of blood, culture, and triatome forms. Typical leishmaniform bodies were found in tissue sections of cardiac muscle fibers from naturally and experimentally infected animals. Cross agglutinations carried out with living cultural forms and rabbit antisera demonstrated a close antigenic relationship between the raccoon trypanosome and T. cruzi (Brazil strain). On the basis of (1) morphology, (2) presence of leishmaniform tissue stages, (3) development in triatomes, (4) infectivity to a variety of mammals, (5) culture characteristics, and (6) cross reactions in serological tests, this parasite is considered conspecific with Trypanosoma cruzi (Chagas, 1909) the causative agent of American human trypanosomiasis.

Introduction. The incidence of trichinosis in the general population of the United States is thought to be about 25 per cent, but may be as high as 35 per cent in some regions. Most cases, however, are subclinical and go unrecognized. In those cases which come to medical attention the mortality rate is about 5 per cent. No specific therapy is known, and the treatment is symptomatic (Gould, 1945). In recent years clinical trials have shown all the anthelminthic drugs to be ineffective in the intramuscular phase of this disease.

Since 1951, clinical studies on the use of ACTH and cortisone have yielded data showing that these drugs are valuable in the treatment of trichinosis (Buyella et al., 1953; Davis and Most, 1951; Faiguenbaum, 1952; Rosen, 1952; Rothenberg, 1951; Sadusk, 1954; Solomon and Seligman, 1952). Significant relief of symptoms has been reported: decrease in fever and eosinophilia, increased muscular strength, and a lessening of pain and fatigue.

Immersion tests were conducted with O. nosophora collected from areas treated for several years with sodium pentachlorophenate and dinitro-o-cyclohexylphenol, and from neighboring control areas, to determine if resistance has developed to these molluscicides in the treated snail populations. No resistance to Na-PCP was demonstrated in snails from areas which had been treated for 7 years, and 4 years, respectively. However, there was a marked degree of resistance to dinitro-o-cyclohexylphenol in snails from a locality which had been treated with DN-1 for 6 years.

DDT was found to be absorbed very slowly from acetone or benzene solutions when applied topically to susceptible and DDT-resistant human body lice. The resistant strain could tolerate larger quantities of applied DDT without any appreciably harmful effect. The feeding of lice through dissected chick skins on citrated human blood containing various concentrations of radioactive DDT showed that the resistant strain could tolerate 100 ppm of DDT in the blood whereas 10 ppm caused 53 per cent mortality in the susceptible strain.

Only resistant lice metabolized DDT in vivo to a relatively nontoxic material unextractable with common organic solvents but partly extractable with methanol. Determination of the metabolite by the Schechter-Haller method yielded a nitrated product which was removed from solution by dilute alkali, unlike DDT, DDE, or DDA.

Both susceptible and DDT-resistant lice metabolized DDT in vitro at approximately the same rate. The nontoxic, water-soluble metabolite gave a red-colored complex in the Schechter-Haller procedure and had solubility characteristics similar to that obtained in vivo.

It appears that an intrinsic biochemical factor which, presumably, interferes with the detoxifying mechanism, might be operative in the susceptible strain. This interference is manifested in vivo but not in vitro.

Although a marked clinical dermatitis is common in some individuals that become closely associated with the bird mite, Dermanyssus gallinae, the literature presents little evidence that this mite will ingest human blood and many investigators feel that this species will never ingest it. The invasion of a New York City apartment by these mites resulting in attacks on the occupants is described. The finding of mammalian erythrocytes in the digestive tract of mites collected from this apartment, some of which were taken from the bed of the occupants, as well as the appearance of fresh blood splotches on the bed sheets resulting from crushed mites which had recently fed, offer some factual evidence that D. gallinae may, on occasion at least, partake of human blood.

Although our study material was represented by fecal preparations from more than 1,400 Egyptians, the number of species of protozoa found was not greater than observed in our previous studies involving far smaller samples of the population. Larger population samples, however, more strongly emphasize that the relationship between type of locality and presence of intestinal protozoans, and that between locality and prevalence of helminths, must be considered separately. Their establishment is dependent upon different means of transmission. Undoubtedly many of the protozoa are passed from person to person by contaminated hands and by food contaminated by hands and/or flies. Many of the peoples in this part of the world are unhygienic in their habits and one heavily contaminated hand thrust into a bowl which serves the entire family provides an effective vector of protozoan cysts and, in some instances, probably trophozoites. These modes of transfer are not greatly influenced by the unusually dry habitats in which many of the Egyptian peoples live. This conclusion is supported by the high incidence of intestinal protozoa in the semi-desert and desert communities.

Entamoeba coli is the most common intestinal protozoan among the Egyptian peoples and the total incidence of the large and small races of E. histolytica is much greater than that listed for other parts of the world. Perhaps the majority of the population would have been found harboring both species had a series of specimens from each person been examined. Balantidium coli was not detected in our studies and Isospora hominis occurred in only two persons.

This study of materials from a wide range of community types demonstrates the relationship between parasitism by some of the helminths and the habitat in which these peoples live. This was to be expected since successful establishment of infection involves intermediate hosts and favorable conditions for proper maturation of the helminth eggs outside the human body.

The present study lists 19 helminths, several species of which, (e.g., Opisthorchis, Haplorchis, Dicrocoelium and Fasciola of the Trematoda, and the cestode, Diphyllobothrium) are not considered parasites ordinarily found among the Egyptian peoples. Ascaris is the most common helminth and hookworm (Ancylostoma) apparently is much

The omnivorous and voracious habits of the large ampullarid snail Marisa cornuarietis are the basis of its predation and competitive action against Australorbis glabratus in Puerto Rico. Field observations have been made on the biology of Marisa in comparison with that of the schistosome vectorial species.

None of a total of 2,030 Middle Eastern nationals tested was positive to histoplasmin or coccidioidin.

Losch (1875) inoculated dogs with dysenteric stools both by mouth and by rectum and was able to produce dysentery in them. At autopsy ulcers containing amebae, similar to those inoculated, were demonstrated in the colon. Kovacs (1892) adopted the intracecal route for inducing amebic infection in cats. Carrera and Faust (1949) demonstrated the high susceptibility of the guinea pig to amebic infection by injecting trophozoites into the terminal ileum after laparotomy. They attempted to detect the progress of the infection by daily examination of freshly passed stool but the findings constituted no dependable index of the severity of infection as determined after death of the animal and consequently they abandoned the examination of feces and had to depend on the autopsy of the animals for the purpose. Rees (1955), in his excellent review on the subject, remarked on the considerable difficulty that may be experienced in ascertaining the prepatent period of rodent hosts because amebae may be multiplying in the cecum and the upper colon without being demonstrable in the fecal pellets.

From November 4, 1954, to March 20, 1956, 1,091 mammals were trapped in southwestern Georgia. Of these, 820 were tested for leptospires by culturing kidney tissue, and 44 (5.4%) were found positive. The leptospires involved were identified by agglutination and cross-agglutinin-adsorption tests as serologically homologous to L. ballum, L. pomona, L. australis A, L. grippotyphosa, and serotype members of the L. hebdomadis and L. mitis-hyos serogroups. The hosts were as follows: opossum for L. ballum and members of the L. mitis-hyos serogroup; gray fox for L. ballum; raccoon for L. ballum, L. pomona, L. australis A, L. grippotyphosa, and a member of the L. hebdomadis serogroup; striped skunk for L. ballum and L. pomona; and wildcat for L. ballum and L. pomona. No correlation was found between the incidence of infection by a given serotype of leptospires and density of the various species of mammals or the total mammalian population.

The isolation of L. australis A., L. grippotyphosa, and organisms belonging to the L. mitis-hyos and L. hebdomadis serogroups is of primary significance. Only a few reference laboratories are routinely testing for the presence of antibodies to these pathogens in either man or domestic animals. There is a need for inclusion of antigens of these serotypes of leptospires in routine agglutination tests and for more intensive efforts to isolate leptospires from suspected cases in humans and domestic animals.

The following new host records were established: gray fox for L. ballum; raccoon for L. ballum, L. pomona, L. australis A, L. grippotyphosa, and a member of the L. hebdomadis serogroup; striped skunk for L. ballum and L. pomona; wildcat for L. ballum and L. pomona; and opossum for members of the L. mitis-hyos serogroup.

Erythromycin, 500 mg, was given every 6 hours for 10 days to six patients suffering from amebic liver abscess.

Two cases apparently responded, the remainder either failed to respond or relapsed.

By comparison with emetine and chloroquine, erythromycin is ineffective in amebic liver abscess.