The American Journal of Tropical Medicine and Hygiene - Volume 9, Issue 3, May 1960

A serologic survey for leptospiral agglutinins was conducted on serums from 240 human beings, 914 cattle, 115 horses, 109 goats, 50 donkeys and 49 sheep, located in three rice-raising areas and one adjacent livestock breeding area in south central Turkey. Employing a very conservative test criterion for a significant serologic reaction, the percentages of positives in the various hosts were the following: man—9.6, cattle—59.0, goats—69.3, sheep—22.4, horses—47.8 and donkeys—58.0. Most of the predominant serologically positive reactions in human beings, goats and sheep were elicited with L. grippotyphosa antigen, a lesser number with screening antigens in the hebdomadis group. In bovine serums, however, in addition to the presence of agglutinins against L. grippotyphosa, a large proportion of seropositive reactions was primarily against antigens of the hebdomadis group, notably L. sejroe. The highest percentage of bovine seropositives was derived from the non-rice-raising area and most of the animals were reactors against the hebdomadis group antigens. Equine positive serums showed a large proportion of predominant titers against L. grippotyphosa and hebdomadis group antigens and also against L. autumnalis; however, a greater variety and multiplicity of agglutinins were observed in these serums.

The titers of human seropositives were either 1:100 or 1:400; however, titers observed in animal serums ranged up to 1:25,600. It was apparent from the distribution of titers that recent episodes of infection in livestock had occurred or were in progress in some of the villages at the time serums were collected.

Differences in prevalence ratios attributed to sex were not evident from the available data for any of the species tested. Generally, the percentage of positives was lowest in youngest age groups of the various species; however, a stepwise increase in the percentage positive in successively older groups was not noted.

These findings indicate that the rice-field regions of south central Turkey are epidemic or endemic foci of leptospiral infections in man and domestic animals, and that most of these infections are presumably caused by L. grippotyphosa and a member of the hebdomadis group, possibly L. sejroe.

Distributions of eggs of the four main geographic strains of Schistosoma japonicum in the viscera of infected hamsters and mice were studied. The results of the study show that the percentage distributions of eggs of this parasite in the visceral organs of its host were influenced by the strain of the parasite, the species of the host, and the intensity of infection in the host. It may be stated that in general, with the C and F strains, the percentage distributions of eggs in the visceral organs of hosts were higher in the liver than in the small intestine; with the J and P strains, higher in the small intestine than in the liver except in mice infected with one male and one female cercariae of the P strain, where the mean of the percentages of eggs in the liver was higher. As to the species of host, the mean percentage of eggs in the small intestine was lower in the hamster than that in the mouse, and vice versa in the large intestine. When the intensity of infection in the host was at the lowest level, the percentages of eggs were mostly higher in the liver and large intestine, and lower in the small intestine, than in the corresponding organs of the host with the high intensity of infection.

Hemagglutination (HA) and bentonite flocculation (BF) tests with 7 crude Echinococcus granulosus and Echinococcus multilocularis antigens were performed. Antisera prepared in rabbits against these antigens, antisera from patients with proven infections of E. granulosus and serum from patients believed to be infected with E. multilocularis were titrated. In both the HA and BF tests absolute specificity was not observed with hydatid fluid, scolices, cyst and membrane antigens of the two cestode species. E. granulosus hydatid fluid proved to be the antigen of choice in both the HA and BF tests of sera from humans with E. granulosus hydatid infections. Diagnostic tests with E. multilocularis antisera were not as satisfactory, suggesting that tests with crude antigens will not detect human chronic infections with this species of parasite.

By precipitation with TCA, 7 fractions were obtained from E. granulosus hydatid fluid, and 11 from E. multilocularis cysts. A number of these fractions were non-reactive in both the HA and BF tests. Fractionated antigens were more sensitive than whole antigens when used with antisera prepared in rabbits. For diagnostic serology, the purified antigens were in some instances more active in the HA test but less reactive in the BF test. For the diagnosis of E. granulosus hydatid infection, the whole hydatid fluid of porcine origin was as reactive as the antigen fractions. For the diagnosis of E. multilocularis hydatid infections, the fractionated antigens prepared from whole cysts were superior.

The intestinal Protozoa found in a sample of 18,064 adults stationed on or affiliated with military stations in southern California but representing all States and many different segments of the population in the United States were, in order of increasing prevalence (% in parenthesis), the following: Embadomonas intestinalis (<0.1); Enteromonas hominis (<0.1); Dientamoeba fragilis (0.2); Trichomonas hominis (0.6); Iodamoeba bütschlii (1.7); Chilomastix mesnili (4.1); Entamoeba hartmanni (3.2); Entamoeba histolytica (2.9); Entamoeba coli (10.6); Giardia lamblia (11.5); Endolimax nana (13.2). Entamoeba polecki was found in one individual only. Host agegroups 24–34, 35–45, 46–56 showed no significant changes in prevalence for any species except Giardia lamblia, which decreased with increasing age.

Various methods of removing reeds from a malaria infested region were compared as to their effectiveness in control of Anopheles larvae. It was found that the mechanical or chemical methods of reed destruction usually resulted in the development of horizontal vegetation which furnished shelter for mosquito larvae.

In contrast, a nutria population of suitable density was able to keep the river course and adjacent ponds clear of vegetation for 3 years. The results obtained with feral nutria in the Naaman swamps were confirmed in five fenced pond farms in various regions of the country.

In the area kept permanently clear of weeds by nutria the drainage capacity of the river and ditches was maintained, and the use of insecticide was decreased substantially.

A spontaneous infection with what appears to be Toxoplasma gondii of an immature Oedipomidas oedipus marmoset is reported. The animal arrived five days prior to death from Colombia and had an overwhelming infection with death due to interstitial pneumonia and pulmonary edema. Organisms identified as Toxoplasma on the basis of morphology and transmissibility to mice were recovered from the carcass and were found in all major organs.

In a village of 529 inhabitants in southeastern Mexico, mass treatments using piperazine in a single-dose, repeated monthly, reduced the ascariasis rate from 28% at the first treatment to no detectable infection at the eighth. Mature worms capable of contributing infectivity to the soil were not seen in post-treatment stools after the sixth month. It is concluded that eradication of human ascariasis by repeated mass treatments can be achieved, at least in a closed population.

Studies of the inhibition by various metabolites of the antitoxoplasmic action of pyrimethamine and sulfadiazine in acute mouse toxoplasmosis, alone and in combination, resulted in the following findings:

• 1.  p-Aminobenzoic acid completely antagonized the effect of sulfadiazine and partially antagonized the effect of pyrimethamine. It also partially inhibited the effect of the drugs in combination.
• 2.  Folic acid incompletely antagonized the effect of sulfadiazine, but did not antagonize the effect of pyrimethamine. It also had no effect upon the drugs when given in combination.
• 3.  Folinic acid did not materially antagonize the action of the combination of pyrimethamine and sulfadiazine or of the drugs individually.

A method is described for actively immunizing man against the venom of the tiger snake.

Over a period of 13 months, increasing amounts of venom were injected into a subject who had been repeatedly bitten by venomous snakes, and who was sensitive to horse-serum. The initial dose was 0.002 mg and the final dose 25 mg of venom.

A pre-immunization titer of 0.2 units of antivenene per ml of serum was present. Three months after the commencement of immunization the titer was 1 unit/ml, while at 4 months a titer of 5.1 units/ml was reached. Depending on the interval of time which then elapsed between injections, the antivenene titer fluctuated between 1.5 and 5.2 units/ml. Four months after the final dose a titer of 2 units/ml was still present.

Venom treated with formalin (toxoid) did not exert a detectable antigenic effect.

The health of the patient was not adversely affected throughout the course of immunization, but transitory local reactions frequently followed the injections of either venom or toxoid. On three occasions mild general reactions occurred.

Evidence is supplied which suggests that after active immunization a titer of 1 unit/ml constitutes in an adult a protective level of antivenene against the bite of a tiger snake containing an average amount of venom.

The nature of the local reactions, the protection afforded by active immunization and the indications for active immunization are discussed.

Serum from rabbits immunized against normal mouse erythrocytes was administered to mice infected with Plasmodium berghei in six experiments involving a total of 105 mice. These mice were given three to eight daily serum injections, starting shortly before infection or 2 days after infection. Mice receiving this serum experienced severe infections and death earlier than did infected control mice. The blood of immune serum recipients contained high percentages of immature erythrocytes, most of which were parasitized. Normal rabbit serum had no effect upon the course of the infection in the one experiment in which such serum was used.

In two of the six experiments, immune serum recipients showed lower parasitemias than did control mice early in the course of the infection. This response was very transient and these mice later showed higher parasite counts than did the control mice.

Three cases of persons who had “creeping eruption” or “cutaneous larva migrans” and developed psychoses manifested as severe mental depressions and findings suggestive of Loeffler's syndrome are presented. It is hoped this note will stimulate further reports and detailed studies to clarify the relationships observed.

The reaction of cercarial antigen-cholesterol-lecithin complex with schistosome antibody provides a simple sensitive slide flocculation test for schistosome infections.

Capacity of the antigen emulsion to react with homologous antibody was greatly increased by removing the antigen-cholesterol-lecithin complex from the salt solution in which it was prepared and resuspending the complex in fresh salt solution.

The S. mansoni cercarial antigen used in the test also reacted with sera from patients with S. japonicum and S. haematobium infections.

While specificity of the test was excellent in other helminthic diseases, cross-reactions with the S. mansoni antigen and T. spiralis anti-sera did occur. This finding is consistent with those obtained from other tests using cercarial antigens.

The excellent sensitivity (98%) and simplicity of the procedure make the test ideally suited for field and survey purposes.

The objective of the present study was to determine the frequency of poliovirus infection in Guatemala, primarily the inapparent infections occurring there. Sero-immunity, as indicated by serum neutralization tests in HeLa cell cultures, was demonstrated to all three poliovirus types. Among a group of 100 adults, 76 individuals had antibodies to Type I, 58 to Type II, and 62 to Type III; none of the group was known to have had overt or clinical poliomyelitis. It is concluded that polioviruses prevail in the Guatemalan population to a much greater extent than the occurrence of clinical disease would indicate. It has also been pointed out that 35% of the individuals tested failed to show seroimmunity to poliomyelitis.

Poliomyelitis must be taken into account by the physician in Guatemala in the differential diagnosis of any atypical fever, especially in non-residents. Vaccination with polyvalent poliomyelitis vaccine is highly desirable for foreigners entering tropical and subtropical areas and the probability that vaccination will become increasingly desirable for residents of Guatemala is suggested. The risk of paralytic poliomyelitis is greater than commonly realized.

• 1.  Twelve fat-balance studies were performed in ten documented sprue patients before and during the administration of 15 mg folic acid given orally and daily over a period ranging from 9 to 44 days, with an average of 23 days for the twelve cases. All patients showed steatorrhea during a period of observation before treatment.
• 2.  Other tests for intestinal absorption such as glucose tolerance, D-xylose excretion, and vitamin A absorption were carried out prior to and after treatment in some cases.
• 3.  Steatorrhea was significantly reduced during treatment in two patients, and it was increased in two other cases. In the remaining eight, folic acid did not produce any significant changes in the steatorrhea.
• 4.  Vitamin A absorption improved in four cases and glucose tolerance in two cases. Results of other tests for intestinal absorption (glucose tolerance, D-xylose excretion and vitamin A absorption), though slightly improved, remained below normal values in other patients.
• 5.  Under folic acid therapy all but one patient showed improvement in general condition, in glossitis, in weight, and in red cells and hemoglobin. The hematologic response to the drug, however, was inadequate in all cases.
• 6.  Probable factors responsible for the poor effect of folic acid on the blood, on steatorrhea and on the malabsorption of glucose, D-xylose and vitamin A are discussed.

Some of the most interesting studies in human malaria in which I have participated have concerned factors of importance in the epidemiology of the disease, especially the conditions under which the infection is transmissible to mosquitoes, and the possible alteration of this transmissibility through the judicious selection and use of antimalarial drugs. One who is engaged in this field of research soon discovers that these conditions can be quite complex and puzzling. For example, the correlation between gametocyte densities in the human host and the infectivity to mosquitoes may be extremely variable, depending on the stage of the infection, the species—or even the strain—of parasite, and many other factors. It is felt that an understanding of these conditions is of considerable importance as an aid to the efforts now underway toward eradication of the disease.

Culex pipiens pipiens and C. p. fatigans were subjected to a comparative study on the role of temperature in growth, longevity, respiration, fat accumulation and utilization, and egg production. In both subspecies, the lower the temperature the longer was the developmental time, the heavier was the body weight, the greater was the amount of fat, and the longer was the wing length. However, the proportion of fat in the mosquitoes reared at all temperatures remained constant. In both subspecies sugar-fed mosquitoes stored a large amount of fat, although this was not as great as that observed in females caught in nature during winter. The lower the temperature the lower was the rate of oxygen consumption. The sugar-fed mosquitoes consumed oxygen at a higher rate than did young and unfed mosquitoes. Young and unfed mosquitoes of both subspecies had the same rate of oxygen consumption; but following sugar feeding, this rate was significantly higher in pipiens than in fatigans. The rearing temperature had no effect on the rate of oxygen consumption of the adult mosquitoes. The dry body weight of previously sugar-fed pipiens and fatigans decreased during simulated hibernation; however, the rate of fat decrease in pipiens was greater than in fatigans. At the time when fatigans females were dying, their fat content was almost twice that of pipiens; at this time the surviving pipiens females outnumbered fatigans females by 3 to 1. As temperature decreased, the time required for blood digestion and for oviposition increased, and fewer females oviposited. At 5°C pipiens females digested their blood meals in about 60 days but no oviposition took place. On the other hand, fatigans did not survive long enough to digest their blood meals.

From the above experimental results it was concluded that (1) the larval rearing temperature has no effect on the ability of the emerging mosquitoes to go into hibernation directly. (2) Prior to overwintering, adult female mosquitoes require carbohydrates, or a combination of carbohydrates and a blood meal to carry them through the winter. (3) Females of southern fatigans, like those of northern pipiens, are capable of accumulating fat reserves if given a perhibernation carbohydrate diet. (4) Hibernating pipiens females outlive fatigans females because they are able to utilize their fat reserves, whereas fatigans can not do so. (5) The inability of fatigans females to survive long hibernation periods at low temperatures may be an important reason for the absence of this subspecies from colder regions.

Mating experiments with several strains of C. p. pipiens and C. p. fatigans at different temperatures showed that fatigans was more active at all temperatures, but was less inhibited than pipiens at the highest temperature. With decreasing intensity of illumination, fatigans began swarming sooner than did pipiens, but ceased shortly after complete darkness was attained, whereas pipiens continued to swarm in the dark.

It is concluded that fatigans does not exhibit a specific temperature adaptation for mating, but that the higher insemination rates at all temperatures were the result of an inherent sexual aggressiveness. However, such differential activity could be a means of limiting the establishment of pipiens in warmer areas, where it would have to compete with the more active fatigans. Furthermore, these differences in response to temperature and changes in illumination could be a mechanism for keeping the populations segregated in some areas where they coexist.

A total of 630 persons with symptoms of acute diarrhea was studied to evaluate the association between recognized enteric pathogens and diarrhea. Approximately 67% of persons for whom treatment was sought were less than 1 year of age. Recognized bacterial pathogens were isolated by a single examination from 57% of the cases. Shigella were recovered from 26%, enteropathogenic Esch. coli from 31%, and Salmonella from 7%. About 90% of all enteropathogenic Esch. coli recovered were from infants less than 1 year old; about 40% of the Shigella isolations were from this group. The cases from which etiologic agents were not recovered showed no characteristic distribution with respect to age of patients or month of occurrence.

Results differ from earlier studies in the southwest in that the rate of association of Shigella with acute diarrhea was lower and relatively few persons other than infants were found with acute enteric symptoms.

Of the 830 poliomyelitis patients with paralysis of 15 days duration or less reporting to the Children's Hospital, Cairo, U.A.R., from July 1957 through June 1958, 497 yielded enteroviruses, 447 of which proved to be polioviruses. Poliovirus type 1 was the dominant type in 1957–1958 while poliovirus type 2 was dominant in Cairo in 1955. Seasonal distribution for the 447 confirmed cases was uniform throughout the greater part of the year. Ninety-four per cent of the cases occurred in children between 7 and 30 months of age, most of these affecting the youngest child in a family. Although certain districts within Cairo proper accounted for more paralytic cases than others, no explanation was available as to the reason. The incidence of paralytic poliomyelitis was at least 4 times higher in the 0 to 4 year-old population of Cairo in 1957–1958 than in similar age groups in Southern United States in 1955. The results reported herein are in agreement with other observations elsewhere in the Middle East, and all tend to emphasize one point: if poliomyelitis is to be successfully controlled in the Middle East, immunization must be completed at the earliest possible age.

Salud Publica de Mexico, by José Alvarez Amézquita, M.D., and Editorial Staff. Epoca 5, Vol. 1, No. 1, 240 pages, illustrated. Mexico, D. F., R. M., Secretaria de Salubridad y Asistencia, 1959.

Assistance Technique en Médecine Africaine. by René Devignat, Directeur Écoles d'Assist'ce Méd., e de Méd. Trop. Elisabethville, Congo, Belg. 1st edition, 167 pages + xv pages, illustrated. Paris, Masson et Cie, 1958. 1.600 fr.

Annual Report, City Medical Health Officer, City of Durban, South Africa. 1958, by G. D. English, M.B., Ch.B., D.P.H., O.T.M. & H. 135 pages, illustrated. Durban, Durban City Health Department (Mimeograph), 1959.

Report of the First Institute on Clinical Teaching: 6th AAMC Teaching Institute, by Helen H. Gee and Julius B. Richmond, Planning Committee, and E. S. Nourse, editors. 233 + xxx pages, illustrated. Evanston, Ill., Association of American Medical Colleges, 1959. Cloth $3.00, paper $2.00.

Water Supply for Rural Areas and Small Communities, by Edmund G. Wagner, Rio de Janeiro, and J. N. Lanoix, Geneva.