Zinc Sulfate Flotation Research Articles

Prevalence Of Intestinal Parasites In Korea

A survey of intestinal parasites infection among Korean people has been carried out during July 1969 to December 1970. A total of 2,250 stool specimens (male 1,101, female 1,146) was collected from all the provinces and Seoul city in Korea. The specimens were examined routinely by direct fecal smear, zinc sulfate flotation and formalin-ether sedimentation techniques. The results are summarized as follows: 1. Of 2,250 specimens examined, l,803(80.l %) were positive for intestinal parasites. 2. The positive rates of intestinal helminths were 1,644(73.1 %) among 2,250; Ascaris lumbricoides 46.0 %, Trichocephalus trichiurus 46.8 percent, hookworm 6.8 %, Trichostrongylus orientalis 7.0 percent, Clonorchis sinensis 12.1 percent, Enterobius vermicularis 1.6 %, Hymenolepis nana 0.7 percent, Taenia species 0.3 %, Metagonimus yokogawai 0.04 percent, Fasciolidae 0.04 % and one case of lung fluke Paragonimu westermani. 3. The positive rstes of intestinal protozoa were 786(34.9 %); Entamoeba histolytica 6.4 %, Entamoeba coli 20.5 percent, Endolimax nana 10.0 %, Giardia lamblia 5.1 %, Trichomonas hominis 1.1 percent, Chilomastix mesnili 0.5 percent, Iodamoeba butschlii 0.6 percent, Enteromonas hominis 0.7 percent, Dientamoeba fragilis 0.1 % and one case of Isospora hominis. 4. Sexual distribution of helminths and protozoan infections showed higher rate in female than that of male, except C. sinensis, H. nana, Taenia species or G. lamblia. 5. Infections of T. trichiurus, hookworm, T. orientalis, C. sinensis, Taenia species, E. histolytica, E. coli and E. nana increased with age. Conversely, H. nana and G. lamblia infections were more predominent in younger ages.

Anatrichosomiasis in African Monkeys

Approximately 29% of 298 African monkeys belonging to 5 species (Erythrocebus patas, Cercopithecus talapoin, C. aethiops, Cercocebus galeritus, and Papio sp.) obtained from various parts of Africa were found to be infected with species of Anatrichosoma. The adult worms were found in the nasal epithelium. The embryonated eggs which accumulate on the epithelial surface were easily removed with a cotton-tipped applicator stick, nasopharyngeal swab, or similar implement. Eggs were rarely found in the feces by routine diagnostic methods. Swabbing of the nasal mucosa was found to be the most reliable and accurate procedure for diagnosis of infections in living animals. Although specific determinations were not made, it appeared that the parasites from the African monkeys were different from A. cutaneum and A. cynamolgi described previously from Asian monkeys. The anatrichosomes are relatively rare and poorly known trichuroids which, to date, have been found in the skin and nasal mucosa of Asian monkeys (Swift et al., 1922; Smith and Chitwood, 1954; Chitwood and Smith, 1958; Allen, 1960) and on two occasions in man (Morishita and Tani, 1960; Le-Van-Hoa et al., 1963). Infections have been recognized more frequently as a result of recovery of adult worms at necropsy than from finding the eggs of the parasite. The latter have been found in scrapings of the nasal mucosa and occasionally in feces (Allen, 1960; Reardon and Rininger, 1968). Reports concerned with this parasite are so few that our knowledge of the species, their host range, and geographical distribution is very limited. Recently, in the course of histological examination of nasal tissues from an African patas monkey (Erythrocebus patas), Dr. Herman Seibold of the Pathology Laboratories, Delta Regional Primate Research Center, observed sections of a nematode in the mucosa and referred the slides to the author for identification. Examination of the sections of worms revealed that they were trichuroids. Their location and the morphology of the fully embryonated eggs found in the tissues indicated that they were a species of Anatrichosoma. Examination of intact worms subsequently recovered from animals at necropsy confirmed the tentative diagReceived for publication 14 January 1970. * Presented at the Forty-fourth Annual Meeting of the American Society of Parasitologists in Washington, D. C. 3-7 November 1969. This investigation was supported by U. S. Public Health Service grants FR 00164, DRFR and Al 06828, NIAID, NIH. nosis. Because there are no existing reports of anatrichosomes in African primates and because routine stool examinations in the past have failed to demonstrate the presence of the parasite in colony animals except rarely, studies were undertaken to ascertain the prevalence of this parasite in African primates and to determine the most suitable method for its diagnosis. MATERIALS AND METHODS The monkeys utilized in the study were maintained in the Delta Primate Center's animal colony or, in some cases, at other institutions. The nasal passages of each animal were swabbed with a dampened, cotton-tipped applicator stick or commercially prepared, sterile, nasopharyngeal swab (Calgiswab?), or rectal swab (SWUBE?), depending on the size of the nostrils. The swabs were examined under a binocular dissecting microscope with incident light to determine whether or not eggs were present. Stool examinations were made by direct-smear, formalin-ether, and zinc sulfate flotation techniques. At necropsy, portions of the nose and upper lip were removed from infected monkeys and fixed in Bouin's solution or 10% formalin. These tissues were processed by routine methods, sectioned at 7 ,i, and stained with hematoxylin and eosin. Worms removed from the tissues in toto were fixed in glacial acetic acid, transferred to 70% alcohol to which glycerin was added gradually, and were brought to pure glycerin by evaporation for microscopic study. RESULTS AND DISCUSSION Histological examination of tissues from infected animals revealed that adult worms usually are located in that portion of the nasal cavity lined with stratified squamous epithelium (Fig. 1). The female worms make extensive burrows in the epithelium as they wander through the tissues, depositing eggs in their wake. The eggs remain in these burrows or

Helminth Survey of Dogs and Cats in New Jersey

Single fecal examinations, using the zinc sulfate flotation technique, were performed on 4,217 animals (2,737 dogs and 1,480 cats) and 3,730 helminth infections were revealed. Of these animals, 685 dogs and 318 cats were treated and necropsied, thus uncovering 584 additional infections not found by flotation. About 55% of the additional infections were tapeworms, and the remaining 45% were nematodes, of which 22% were light infections, 17% were immature, and 6% consisted of male worms only. In recent years there have been a number of surveys of helminths of dogs and cats, including one from this laboratory (Burrows and Lillis, 1960). Since many surveys are based on single fecal examinations and since additional species are often found in those animals that are necropsied, it appeared that many surveys probably fail to reveal a fair percentage of infections harbored. To determine this, a detailed study was made of records of stool examinations, treatment results, and necropsies of dogs and cats used in this laboratory from 1 April 1960, the end period of the previous report (Burrows and Lillis, 1960), through 31 October 1966. MATERIALS AND METHODS The animals were strays, supplied by a regular dealer who obtained them from central New Jersey, the same general area as in earlier reports of other infections (Lillis and Burrows, 1964; Lillis, 1964; Burrows and Lillis, 1965, 1967). The animals were housed in individual cages and remained at the laboratory only a few days to a few weeks, so there was no opportunity to acquire an infection while at the laboratory. Stool examinations were performed shortly after receipt of the animals, using the zinc sulfate flotation technique (sp. gr. 1.2). The strong solution was used because it will float heavier eggs, such as Taenia (Burrows, 1965). All helminth eggs and larvae found by flotation were identified and recorded. Data from the necropsy of dogs and cats were obtained during routine anthelmintic screening trials. These animals were known to be infected with certain parasites, as found on flotation, and were used in chemotherapeutic trials of experimental compounds. A stainless steel pan was placed in the bottom of each cage and all feces passed were collected and examined for worms Received for publication 10 April 1967. * Present address: CIBA Research Farm, Three Bridges, New Jersey 08887. present. The specimens were washed in a 40-mesh sieve and the sieve contents examined, a little at a time, in a black-bottomed pan for worms passed. At necropsy, the small intestine was examined carefully for worms remaining. The worm burden of an animal was the sum of the worms passed plus those remaining at necropsy. Since numerous animals were given compounds that did have anthelmintic activity, many worms passed out in a disintegrated condition, and sex, species, and degree of maturity could not always be determined. For some animals, no worms could be recovered at all, as a result of disintegration and in this case, the intensity of the infection was considered light, and in the range of from one to 10 worms. Infections of hookworm and whipworm in dogs and hookworm and ascarids in cats, that fell in various ranges, were counted to demonstrate the intensity of the worm burdens in the necropsied animals.

A comparison of Kato thick smear technique with zinc sulphate flotation method, for the detection of helminth ova in faeces.

A comparison of Kato thick smear technique with zinc sulphate flotation method, for the detection of helminth ova in faeces.

Trematodes of New Jersey Dogs and Cats

During the period from 1959 to 1964 the following nine species of trematodes were found in New Jersey cats and dogs: Eurytrema procyonis, Parametorchis complexus, Phagicola longus, Cryptocotyle concava, C. lingua, Echinochasmus schwartzi, Paragonimus kellicotti, Alaria canis, and A. marcianae. E. schwartzi, and A. marcianae are redescribed. Trematodes are reported relatively infrequently from dogs and cats in North America, whereas nematode and cestode infections are rather common. During the period from 1959 to 1964 we found 23 fluke infections in animals examined in our laboratory. We probably missed others, because we used only the zinc sulfate flotation technique in stool examinations in our search for nematode infections, and operculated eggs fail to float in many cases. The dogs and cats came from central New Jersey, particularly Monmouth and Burlington counties. We cannot determine the exact locality of any specific animal, for the dealer who supplies us collects strays throughout the area. Living flukes from these animals were relaxed in menthol solution prior to fixation, with the result that relatively few were distorted. Permanent preparations of a number of these flukes were deposited in the USNM Helm. Coll., Beltsville, Maryland, and their accession numbers are given below. The dates after the accession numbers refer to the dates the flukes

Mating of Ancylostoma caninum in Relation to Blood Loss in the Host

By oral inoculation of juvenile or adult worms, unisexual or bisexual Ancylostoma caninum infections were established in 39 young dogs. Less than 100 adult females caused rapid blood loss and anemia in two dogs at the time when the worms began laying infertile eggs. Equally heavy all-male or balanced male-female infections did not cause detectable anemia. A higher percentage of males remained in recipient dogs when transferred with (62%), than without (49%), females, but females became established equally well with or without males (average 55%). The average rate of laceration (per 100 worms) was greatest in all-female (147) and unbalanced infections (97 and 134), least in all-male infections (21), and relatively low but highly variable in balanced infections (57, range 3 to 122). Laceration rate was not related to overall population density, but when worms were very unequally distributed as they often were in all-female infections, or bunched as they were when males congregated around receptive females, the focal laceration rates were high. Blood in the worm's intestine was evident more frequently in females than in males, being seen in 53, 64, and 80% of females in balanced, unisexual, and unbalanced infections, respectively. The corresponding rates for males were 26, 9, and 37%. More than half of the worms of both sexes were unattached to the intestinal mucosa when observed 15 to 30 min after death of the host through Nembutal injection into the heart. The observations suggest that the female of A. caninum normally mates at intervals of 3 weeks or less, that mating behavior is attendant with laceration of the intestinal mucosa, especially when the sexes are highly unbalanced, and that mating may rank high among those activities of the hookworm which cause blood loss and anemia in the host. It is generally accepted that hookworms cause anemia and that the anemia results directly from blood losses caused by the worms. In the freshly opened intestine of infected dogs, blood is often seen oozing from the lacerated mucosa and filling the intestine of the hookworms. Estimates have been made of the amounts of blood passing daily through the intestine of hookworms (Wells, 1931) and the daily losses of blood into or from the intestine of the host (Roche, 1957a, b; Foy et al., 1958; Clark et al., 1961). The rate of blood loss and the consequent anemia are, in general, proportional with the number of worms present in the intestine. In extreme cases this relationship is clear and indisputable. In some instances, however, the Received for publication 6 December 1963. * Supported by Grant AI-04919 from the National Institutes of Health, U. S. Public Health Service. t Department of Medical Zoology, Kyoto Prefectural University of Medicine, Kawara-machi, Kamikyo-ku, Kyoto, Japan. relationship between worm burden and blood loss or anemia is not evident, and the lack of such a relationship cannot always be explained on the basis of duration of infection or nutriional status of the host (Foy and Kondi, 1960, 1961). The present study was undertaken to examine the possible role of sex and mating behavior of Ancylostoma caninum in the causation of blood loss in the dog. MATERIALS AND METHODS Thirty-nine mongrel dogs 3 months to approximately 6 months of age were caged separately, given a ration of commercial canned dog food, treated for helminths until stools were negative (by zinc sulfate flotation) for a period of at least 15 days, and given infections with adult or adolescent worms of predetermined number and sex. Adult worms carefully removed from freshly killed, naturally infected dogs, or adolescent worms 7 to 11 days of age, similarly taken from experimentally infected dogs, were examined individually under suitable magnification to determine the sex. Counted numbers of the worms were then transferred to 1-ml gelatin capsules and placed over the glottis of a recipient dog. Usually the capsules were

Comparison Of Detection Rate Of Some Trematodes' Eggs By Combined Technique Of Formalin-Ether Sedimentation And Zinc Sulfate Flotation

Combined technic of formalin-ether sedimentation and zinc sulfate flotation was carried out to compare the detection rate of Paragonimus eggs in feces between formalin-ether sedimentation technic and zinc sulfate centrifugal flotation, using the feces of cat infected with Paragonimus westermani for former and intestinal contents of rabbit infected with Metagonimus yokogawai for latter. And following results were obtained. 1) Zinc sulfate method was highly excellent in detection of Paragonimus eggs in feces, on the contrary, formalin-ether technic was very poor, and the other hand, formalin-ether technic was highly excellent in detection of Metagonimus eggs, on the contrary, zinc sulfate method was extremely poor. 2) The time which was needed in carrying out the combined technic was shorter than the cumulative time of each of the formalin-ether technic and zinc sulfate method was. 3) Author emphasizes that the combined technic may be used in general parasitic examination of feces, so that excellent results would be obtained in detection of all kinds of helminthic ova and protozoa.

The Effect of Bile Flow on Giardia duodenalis Race Simoni in the Intestine of a Laboratory Strain of Rattus norvegicus

The rat was used to determine the effect of bile on the survival of Giardia duodenalis race simoni. Using surgical techniques, the flow of bile into the intestines of laboratory rats known to be infected with Giardia was eliminated. Approximately 24 hr after surgery, several locations in the intestines of the altered rats were examined for trophozoites. From the results obtained, it appears bile in the intestine is necessary for survival of Giardia in the laboratory rat. In the past, certain investigators have implied Giardia was either a parasite of the gall bladder and bile ducts or it caused disease of the liver, gall bladder, and bile ducts (Kantor, 1923; Smithies, 1928; De Muro, 1939; Grott, 1939; Gondard, 1952). Others (Goia et al., 1961; Mandoul, 1939; and Cain and Sikorav, 1938) did not believe Giardia was either a parasite of the hepatic system or it caused any disease related to the liver or its ducts. These references all pertained to human Giardia duodenalis race lamblial infections. Hegner and Eskridge (1939), checking for the parasite in a different host, examined the bile ducts of 123 rats and found no Giardia. More recently Karapetyan (1960) made a point of removing the bile by centrifugation from the material used as the inoculum in his in vitro studies on Giardia, so as not to interfere with his results. The only individuals who actually performed in vivo experiments using bile or bile salts were Hegner and Eskridge (1937). They stated sodium glycocholate favored the growth and multiplication of Giardia in rats, sodium Received for publication 25 February 1963. * Paper No. 5050, Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul. This work partially supported by the University of Minnesota Graduate School Fund. 1The species designation used in this paper is of Filice (1952) in which he limits the number of species and assigns nontaxonomic race names to differentiate the various forms. taurocholate had no effect, and oleic acid was detrimental to the parasite. The present study was initiated to determine if bile had an effect on the rat Giardia, in vivo, as suggested by the work of Hegner and Eskridge (1937). Goodchild (1958), in his experiments on the effect of bile on Hymenolepis diminuta in the laboratory rat, concluded that bile contains a factor or factors apparently necessary for normal growth and maturation of adult H. diminuta in the rat host. MATERIALS AND METHODS Eighty-seven Sprague-Dawley rats were used in these experiments. They were fed Giardia duodenalis race simoni cysts ad lib. in the drinking water, the same method used in previous studies (Bemrick, 1962). The rats were used singly or in pairs at varying intervals following infection. In each individual, Giardia cysts were demonstrated by the zinc sulfate flotation technique before surgical procedures were initiated. Observations on Giardia-infected rats by Haiba and Williamson (1952) have indicated starvation induced elimination of Giardia from the intestinal tract. To avoid this, the rats were not starved prior to surgery. Rats positive for Giardia were surgically altered in one of seven ways: 1. The bile duct was ligated in two places with number 6-0 silk suture at the anterior one-third, and the duct was severed between the ligatures. 2. The bile duct was cannulated with Intramedic number 10 polyethylene tubing, exteriorizing the bile flow. The cannulae were inserted in the anterior one-third of the duct. The ligatures and cannulae were always placed in this area to try to prevent interference with the flow of pancreatic juices. The technique used was similar to

Effect of Stilbazium Iodide on Enterobius vermicularis and Other Intestinal Helminths

A total of 70 patients were treated for intestinal helminths with stilbazium iodide, a quaternary pyridine. A single dose of approximately 10 mg/kg of the base was curative in all of 30 cases of Enterobius vermicularis so treated. The drug was effective both as ordinary and enteric-coated capsules. Use of total dosages of 2.25 or 3.00 g of the drug given over a period of 3 days cured 7 of 24 Trichuris trichiura infections, with egg reduction ranging from 76 to 97%. All of five Strongyloides stercoralis infections appeared to be removed, but the effect against hookworm infections was less favorable, with only 2 of 12 eliminated and with egg reductions of 20 to 58%. In all recipients there was a red coloration of the stools due to presence of drug. Mild nausea and vomiting occurred in about 13% of the patients receiving the ordinary capsules but not in the 15 patients receiving the enteric-coated preparation. Stilbazium iodide, a quaternary pyridine, has been found useful against a number of helminths of lower animals. Burrows and Hunt (1962) demonstrated elimination of Syphacia obvelata from mice with dosages of 10 mg base/kg or higher and over 90% elimination at levels down to 2.5 mg base/kg. At somewhat higher levels, two or three 25 mg base/kg doses of the drug were effective against a wide range of nematode parasites of dogs and cats (Burrows and Lillis, 1962). Toxicity studies reported by Burrows and Hunt (1962) indicate a wide margin of safety with this compound. Doses of up to 100 mg/kg/day for 4 weeks in dogs and monkeys produced no histopathological abnormalities, and the major side effect was a depression of appetite and lower weight gain at the higher drug levels. Feces from test animals were red-colored due to presence of the drug, but all tests were negative for blood. Unpublished reports (Fite, 1962) have shown stilbazium iodide to be effective at Received for publication 15 March 1963. * Department of Health, Education, and Welfare, Public Health Service, National Institute of Allergy and Infectious Diseases, Laboratory of Parasite Chemotherapy, Section on Epidemiology, P. 0. Box 717, Columbia, South Carolina. tAssistant Medical Director, Pineland, State Training School and Hospital, Columbia, South Carolina. single dosages of 10 mg/kg in the treatment of Enterobius vermicularis infections in children. No side effects of note were encountered in these treatments. The study reported here was undertaken to determine the effect of stilbazium iodide on helminth infections in mental patients. MATERIALS AND METHODS The patients treated were white and Negro male and female residents of a mental hospital and a training school for mental defectives. Presence of worm infections was determined by examination of three consecutive daily cellulose tape samples for E. vermicularis and by the examination of two stool specimens from each patient for presence of other intestinal helminths. Stool examinations were by direct smear and by a zinc sulfate flotation method. The density of worm eggs in the feces was determined by the Stoll method corrected to formed stool basis and using the average of the two specimens. Posttreatment examination for E. vermicularis consisted of seven consecutive daily cellulose tape samples, usually begun 7 days after completion of treatment. For other helminths, two stool specimens were examined by direct smear and zinc sulfate flotation, usually 1 to 2 weeks after completion of treatment. If eggs were found, the density was again measured by the Stoll method. The drug was given in several different forms. It was supplied either in ordinary gelatin capsules, containing 100 mg or 250 mg of the base, or in enteric-coated capsules containing 250 mg of the base. We are grateful to Burroughs Wellcome and Co. (USA) for providing the stilbazium iodide

Stilbazium Iodide as an Anthelmintic. II. Against Various Nematodes of Dogs and Cats

Stilbazium iodide, which was effective against the mouse pinworm Syphacia obvelata, was tested against three species of hookworms, three of roundworms, and one of whipworm in 120 dogs and cats. Two or three 25 mg base/kg doses removed most Ancylostoma caninum, A. tubaeforme, Uncinaria stenocephala, Toxocara canis, and T. cati, but Toxascaris leonina was more resistant. The drug is active against Trichuris vulpis in dogs when it is given in courses of 3 to 6 doses of 25 mg base/kg or higher. Two or more courses may be necessary for puppies and for dogs having narrow cecal openings or extensively coiled ceca. Except for five dogs with atypical ceca, 24 of 29 dogs given these multiple doses averaged over 90% elimination of whipworms, with 18 of the 24 having complete clearance. Vomiting is negligible in these animals provided the dose is less than 50 mg base/kg. This compound is in human clinical trial against hookworms, ascaris, whipworms, and pinworms. Some of the pyridines found active against the mouse pinworm Syphacia obvelata were tested against various nematodes of dogs and cats and were found effective against a number of species (Phillips and Burrows, 1961; Burrows, Hunt, and Lillis, 1961). The most active against Syphacia, stilbazium iodide, is relatively nontoxic (Burrows and Hunt, 1962) and it was found also to be the best against dog and cat nematodes. A series of trials was set up to test the effectiveness of stilbazium against three species of hookworms, three of roundworms, and one of whipworm in these animals. Several different dosage levels were used in these experiments in an endeavor to find the optimum dosage for the various species. MATERIALS AND METHODS From stool examinations done on all stray dogs and cats and from registered beagle puppies received by this laboratory, those animals showing moderate to large numbers of eggs of one or more species of nematodes in zinc sulfate flotation preparations were selected for trial. One hundred and twenty animals (55 dogs, 32 puppies, and 33 cats) were used in the trials. There were 207 infections (106 in the dogs, 56 in the puppies, and 45 in the cats) in these animals against which stilbazium was tested. Dogs and puppies selected for treatment were switched from a Gaines meal diet to a canned dog food diet the day prior to treatment as it is less time-consuming to search for passed worms in the canned food debris. Cats were kept on canned cat food before and during treatment. The compound was administered orally in gelatin Received for publication 1 August 1962. capsules according to mg of base per kg of body weight. As the iodide salt makes up nearly onefourth of the weight of the compound, it was necessary, for example, to give 32 mg of the compound per kg in order to have 25 mg of base per kg. Animals given a single dose in a day received the drug between 0830 and 0930 and were fed between 1230 and 1330. Those given 2 doses a day had the second dose at about 1600. All fecal specimens were collected from all animals after treatment began, and this was continued until the animals were autopsied. Those given a single dose were autopsied after 48 hr; those dosed for 2 or more days were autopsied 48 hr after the last dose, except that those treated for whipworm infection were followed for 7 days after the initial dose. Animals were killed with a lethal dose of Nembutal given in the heart and were autopsied i mediately. Fecal material was washed through a 40-mesh sieve and the sieve contents examined, a little at a time, in a black-bottomed pan for worms passed. At autopsy the stomach and intestines were examined carefully for worms remaining. The contents of the large intestine were considered part of the last fecal specimen, except for living whipworms still attached to the cecum or large intestine. The percentage of elimination of worms was computed for each species of helminth of each animal by dividing the number passed by the number harbored. The average percentage of elimination of a species, to the nearest whole digit, was found by averaging the percentages of all animals harboring that species and having been given the same dosage level. It was not possible to autopsy six of the dogs or the 32 puppies used in these experiments, but the percentage of elimination was determined from the averages of three preand three post-treatment Stoll egg counts, the former being done the week prior to treatment and the latter beginning 7 or 8 days after the initial dose.

Parasitologic surveys in Cali, Departamento del Valle, Colombia. I. Incidence and morphologic characteristics of strains of Entamoeba histolytica.

Conclusions and SummaryA parasitologic survey was made of 990 persons in the city of Cali, Colombia, from whom 1,178 fecal specimens were collected. Stools were examined macroscopically, by direct double cover-glass and by zinc sulfate flotation technics, and in many cases following fixation in MIF medium, on the day they were passed. Attention was focused on E. histolytica, whose prevalence and morphologic character are here reported.The incidence of infection was 35.5 per cent in 651 inhabitants of one of the wards of the city; 40.3 per cent in 144 patients of a mental hospital; 11.1 per cent in 72 patients in the hospital of the University of Valle; 6.4 per cent in 93 private clinic patients; and 3.3 per cent of 30 fecal specimens from autopsy material.The incidence tended to be familial since it was significantly higher in 13 selected families than in 99 others, while no positives were found in 21 families. The few trophozoites compared with the number of cysts in the stools suggests a clinically mild infection, due possibly to the large amount of undigested starch in the average stool of the group, which might tend to keep E. histolytica in the large intestine; however, clinical and necropsy evidence indicates that deep and extensive invasion of the tissues may occur, resulting at times in death.Both a large and a small race of E. histolytica were found in the numerous strains studied. The former averaged 11.8 µ in diameter and contained 1–4 large sausage-shaped chromatoidal bodies; the latter measured most frequently between 6.8 and 7.7 µ and contained several rice-grain chromatoidals. The large race was found four times as often as the small race. The races could also be differentiated by structural characters of the nucleus as well as by cell contents, but there was no evidence that they were separate sepcies, or that the large race was more apt to invade tissues than the small one, under the prevailing conditions.

Experimental Entamoeba histolytica infections in man.

Summary Eighty-one experimental Entamoeba histolytica infections were studied in human volunteers at a state penitentiary. Inoculation of 2,000 to 4,000 cysts derived directly from a non-symptomatic “carrier” or after one or two passages through volunteers, produced infections in 42 of 42 individuals not medicated or previously infected; heavier inocula did so in 4 of 4 others. Prepatent periods, based on zinc sulfate flotation and saline smear fecal examinations, varied from 2 days to 4 months. In all but 2 of 48 individuals the stools were positive within 2 weeks; 68.7 per cent were positive in 7 days or less. An extraordinarily long prepatency of 4 months in one case was associated with abnormally pale, mucoid stools. From 33 individuals followed for more than 1 month after infection, 86 per cent of the stools examined were positive. In one there were 3 periods of 4 to 7 weeks when amebae could not be demonstrated. Among 23 infected individuals observed for 9 to 14 months there were 7 who apparently lost their infections spontaneously after 3 weeks to 8 months. One of 3 individuals who had spontaneously lost infections was refractory to reinfection when given two inoculations of 4,000 cysts. None of the volunteers developed symptoms that could be associated with the amebic infections. However, the strain of amebae used in the human experiments could not be regarded as non-pathogenic, since it produced typical amebic lesions in dogs, guinea pigs and rats, and was as pathogenic in guinea pigs and rats as a recently isolated strain from a frankly dysenteric patient.

Intestinal protozoa, helminths and bacteria in Tahiti, French Oceania.

Summary A stool survey in which 560 individuals in Tahiti, French Oceania, were examined for intestinal protozoa, helminths and bacteria, yielded the following prevalence rates: E. histolytica 22.3 per cent, Giardia 10.0 per cent, Trichuris 44.0 per cent, hookworm 38.0 per cent, Ascaris 12.9 per cent, Shigella 3.9 per cent, Salmonella 0.9 per cent. Prevalence rates of other parasites are shown in Table 1. A comparison of procedures used in examining stools for cysts of intestinal protozoa indicates that, for the most part, the zinc sulfate flotation procedure is more efficient than either the direct film or the film stained with iron-hematoxylin. In a comparison of the combination of any two of these methods, the iron-hematoxylin film and zinc sulfate flotation together produced the highest percentage of positives. It is emphasized that the direct film should always be used in examining for trophozoites. The complement fixation test for amebiasis was performed on 25 serums procured from individuals harboring E. histolytica. Eighty-four per cent yielded positive tests. Five serums from individuals whose stools were negative for E. histolytica showed a negative complement fixation reaction.

Treatment of ascariasis in children with hetrazan syrup.

Summary One hundred and twenty five Honduran children were treated for ascariasis with 1-diethylcarbamyl-4-methylpiperazine hydrochloride (Hetrazan®) in a syrup which contained 30 mg. of the drug per cc. Of the dosages employed, the most effective was 12 mg. per pound of body weight daily for 4 days; in 80 per cent of 30 cases this amount resulted in absence of ascaris eggs from concentrated (zinc sulfate flotation) stools on both of two post-treatment examinations. Smaller amounts gave less satisfactory results. Eighteen mg. per pound of body weight appeared to be too toxic. Factors effecting the apparent cure rate are discussed. The most important are the criteria of cure and the season of the year during which the study is done. It is concluded that when it is undesirable to fast or purge, diethylcarbamazine may be a satisfactory vermifuge. It should be of particular advantage in private practice. However, it is not an ideal compound for mass treatment because multiple doses are necessary.

A study of laboratory methods for diagnosing Endamoeba histolytica and their application to 5,048 persons from the Chicago area.

The paper presents a complication of extensive studies made on methods used for the detection of Endamoeba histolytica, and the application of those methods to the examination of more than 13,000 fecal specimens from 5,048 persons during the past 7 years in Chicago and Cook County, Illinois. Combined fecal and proctosig-moidoscopic specimens examined within 30 minutes after collection, employing hematoxylin-stained slides and zinc sulfate flotation, gave optimal results. The irregular behavior of E. histolytica at different temperatures is presented, necessitating their preservation if examination is not carried out within 30 minutes. Advantages of polyvinyl alcohol and Schaudinn's fixative for hematoxylin stained slides and those of formalin and D’Antoni’s iodine for flotation were pointed out. Results of stool examinations for other components than parasites and bacteria were compiled and their lack of value for etiological, but usefulness in guidance of symptomatic treatment were shown. The approximate proportion of E. histolytica infestations in patients suffering from chronic intestinal disturbances in the Chicago area is estimated as 20 ± 3 percent.

Zinc sulphate flotation of faeces

The direct faecal film and Faust's zinc sulphate flotation technique are compared in a series of 1,539 specimens. The overall gain by the use of this technique is 179 per cent.

Modification of the Faust method in the detection of cysts and ova.

T HE Faust method for the concentration and flotation of cysts and ova has proved valuable as a diagnostic aid in certain infections of the gastrointestinal tract, particularly amebiasis.l During the summer and fall of 1945, everincreasing troops with amebiasis were arriving from the Pacific Theatre of Operations. The diagnosis on some of these cases was confirmed immediately by the direct smear method alone due to the great number of Endamoeba histolytica cysts present. Nevertheless, some clinically diagnosed cases continued to exist in which negative results were consistently obtained both by the direct smear and the Faust zinc sulfate flotation methods. Experience had taught us that the latter is the better method in the search for cysts, so we began to suspect that our negative results occurred because cysts were inconsistently present in the stools or because the clinical diagnosis was incorrect. As recommended by Faust and others,l patients were purged with a saline cathartic and subsequent stools were examined.2 Both vegetative and cyst forms were recovered in some of the cases, the latter forms being found mostly by the zinc sulfate method. In spite of the purgation, only a few cysts were found. The remaining negatives were examined daily for a week and remained negative even after purgation. Thinking that in the routine method of Faust the stool sample might be too small, we decided to modify the method by combining it with my method for detecting schistosoma which had given excellent results in over 25,000 examinations of 800 patients with schistosomiasis japonica.3 The modified method is as follows.

The Acid-Ether Centrifugation and the Zinc Sulfate Flotation Techniques as Methods for the Recovery of the Eggs of Schistosoma Mansoni 1

"The Acid-Ether Centrifugation and the Zinc Sulfate Flotation Techniques as Methods for the Recovery of the Eggs of Schistosoma Mansoni" published on Jul 1945 by The American Society of Tropical Medicine and Hygiene.

The Diagnosis of Oxyuriasis: Comparative Efficiency of the NIH Swab Examination and Stool Examination by Brine and Zinc Sulfate Floatation for Enterobius vermicularis Infection

The Diagnosis of Oxyuriasis: Comparative Efficiency of the NIH Swab Examination and Stool Examination by Brine and Zinc Sulfate Floatation for Enterobius vermicularis Infection