Bentonite Flocculation Test Research Articles

Delayed Skin Sensitivity in Schistosomiasis

An evaluation of delayed skin reactivity to a schistosome skin test antigen was made in a group of 49 adult male Puerto Ricans and 20 adult male controls from the continental United States. The immediate 15-min histaminic response and the 24-hr, 48-hr, and 72-hr skin induration reaction were recorded. In a second study, 23 normal controls were skin tested with similar adult worm antigens at higher concentrations. A wheal area of 120 mm2 or greater was considered a positive reaction for the immediate 15-min skin response. Induration of 60 mm2 or greater at 24 or 48 hr was selected as a positive delayed reaction. Of the 49 test subjects, 22 (45%) had positive immediate responses and 15 (31%) had positive delayed responses. The 20 normal controls had no positive immediate and only one had a positive delayed reaction at 24 hr. Using stronger antigens in control subjects, 3 of 23 individuals reacted to a 50 ug N/ml antigen, whereas 2 reacted to the 100 ,ug N and 200 A/g N/ml antigens. Evaluation of circulating antibody by serologic tests of all the individuals indicates some correlation with the immediate skin reaction but none with the delayed response. Seven of 22 subjects with positive immediate skin reactions had one or more positive serologic tests for antibodies. Only one of the six subjects with negative immediate and positive delayed responses had a positive serology. Three test subjects had positive complement fixation tests. These three individuals were passing eggs of S. mansoni. The remaining test subjects were negative for eggs by one stool examination. This study indicates that there may be a delayed skin response to schistosomiasis but its clinical and immunologic significance requires further study. Skin tests employed in clinical practice are of two types: immediate and delayed. The immediate intradermal reaction is associated with humoral or immediate hypersensitivity, whereas the delayed skin test is associated with cellular or delayed hypersensitivity. The role of delayed hypersensitivity in schistosomiasis is not well understood, and has not been extensively investigated. Khalil and Hassan (1932), using a 0.4% carbol saline extract of adult Schistosoma bovis and Schistosoma spindale, skin tested 136 parasitologically proven cases of schistosomiasis and 42 negative controls. Using these heterologous antigens, they noted four delayed skin reactions among the 136 infected individuals tested. Pellegrino and Memoria (1960) reported late skin reactions in 24.2% of the children and 29.4% of the adults tested with an extract of adult Schistosoma mansoni. Sadun and Biocca (1962) observed delayed skin reactions in a study made in Sardinia with Received for publication 6 June 1969. * Requests for reprints should be addressed to I.G.K., Parasitology Section, National Communicable Disease Center, Atlanta, Georgia, USA 30333. t U. S. Public Health Service, U. S. Penitentiary, Atlanta, Georgia. + U. S. Public Health Service, National Communicable Disease Center, Parasitology Section, Atlanta, Georgia 30333. individuals sensitized to S. bovis cercariae and tested with antigens of S. mansoni. Because of the paucity of information on delayed skin sensitivity in schistosomiasis, this study was undertaken to delineate further its presence in an unselected population from an endemic area. It was also attempted to determine the characteristics of response to different concentrations of antigens and to present a standard method of application. Using an extract of adult worms of S. mansoni, 49 adult male Puerto Ricans and 20 adult male controls were skin tested; both immediate and late skin reactions were recorded. In addition, sera from the Puerto Rican subjects skin tested were evaluated for schistosome antibody by a bentonite flocculation test, a cholesterol-lecithin flocculation test, and the complement fixation test. Stools from 20 individuals were evaluated for the presence or absence of eggs of S. mansoni. Analysis of the skin tests indicates that infection with S. mansoni can, in fact, cause delayed skin reactions in man and, in addition, this reactivity can be elicited with a standard dose of adult worm extract utilized widely for testing of immediate hypersensitivity by intradermal injection. MATERIALS AND METHODS Two investigations were carried out. The first study involved 49 Puerto Rican inmates of the U. S. Penitentiary, Atlanta, Georgia, and 20 na-

The Use of Antibody-sensitized Latex Particles to Detect Plant Viruses

In a previous paper (Abu Salih, Murant & Daft, 1968) we compared two highly sensitive serological tests, the passive haemagglutination (PHA) and bentonite flocculation (BF) tests, for detecting plant viruses. These tests depend on the attachment of either antigen or antibody to a carrier material (tanned red cells or bentonite particles). The PHA test was several hundred times more sensitive than the tubeprecipitin test and twenty to eighty times more sensitive than the BF test but had two main disadvantages. These were the short storage life of the red cells (which could be largely overcome by treating them with formalin) and the need to use high concentrations of antiserum globulin preparations to sensitize the red cells optimally. In contrast, bentonite particles could often be sensitized with lower concentrations of the serum globulin preparations and were stable for many months. Both kinds of sensitized carrier particles were time-consuming to prepare and some batches differed in behaviour from others.

The bentonite flocculation test in the serology of tuberculosis. I. Purification of BCG antigens.

Fractionation of unheated bacillary extract of BCG has yielded a carbohydrate fraction which sensitizes bentonite to react with circulating antibodies to M. tuberculosis in human sera. This fraction does not contain tuberculin-like protein material in appreciable amount, but is rather a mixture of carbohydrates, varying in molecular size and all possessing bentonite-sensitizing activity.

The Distribution of Rheumatoid Factor and Rheumatoid Arthritis in the Families of Blackfeet and Pima Indians

AbstractAn analysis of the distribution of RF and RA among the families of the Pima and Blackfeet Indians has shown evidence of familial aggregation of positive bentonite flocculation tests and RA within a single generation in the Pima tribe. No evidence could be found that these characteristics were determined by hereditary factors. The data suggest that RF (BFT) and possibly RA were determined by environmental factors in the Pima Indians, but no direct evidence of this could be found in the Blackfeet tribe. It is postulated that RF and RA may be determined by environmental factors operating maximally during the period of infancy, childhood or adolescence.

Parasitic serologic studies in Somaliland.

SummaryA total of 191 sera collected in Somalia was tested for antibody to Schistosoma haematobium by three serologic tests, to Echinococcus granulosus and filarial antibodies by bentonite flocculation tests, and to Toxoplasma gondii and Entamoeba histolytica by hemagglutination tests.The prevalence rate of Schistosoma antibodies as determined by the BF, C-L, and FA tests was 59.7%. Serologic tests indicated that hydatid infection does not, at present, appear to be a human problem but a veterinary one. Filarial antibodies were more prevalent in the nomadic group, Toxoplasma antibodies were found in 10% of the people tested, and ameba antibodies in 22%.The seroepidemiologic studies have added further information on the parasitic status of one small area of Somalia.

Trichinosis in Cork.

An outbreak of trichinosis involving at least 26 people in Cork in 1967 is described. One death possibly due to the disease is reported. It was not possible to trace the source back to any particular bacon factory. The vehicle was almost certainly sausages and /or a pork product consisting of sausage meat and scraps of raw pork. There was a preponderance of female cases. The bentonite flocculation test and latex agglutination test are useful diagnostic adjuncts. Thiabendazole is a possible preventive and curative drug in the disease.

Comparison of the Passive Haemagglutination and Bentonite Flocculation Tests for Serological Work With Plant Viruses

Summary The passive haemagglutination and bentonite flocculation tests were compared for detecting plant viruses, using antibody-sensitized tanned red cells or bentonite particles. Parsnip yellow fleck, raspberry ringspot, turnip yellow mosaic, narcissus mosaic, potato X and tobacco rattle viruses were detected by both tests in purified preparations and, where studied, in crude plant extracts. The highest antigen titres were obtained only when the red cells or bentonite particles were sensitized with optimal amounts of antibody; these had to be found experimentally because they differed between antisera and between the two tests. In comparative experiments the bentonite flocculation and passive haemagglutination tests were respectively about 2 to 5 and ioo to 125 times more sensitive than tube-precipitin tests for detecting the elongated viruses and about 10 to 20 and 500 to 600 times more sensitive for detecting the isometric viruses. The minimum concentrations of virus detected were 1·8 to 2·6 µg./ml. with the bentonite flocculation test and 0·04 to 0·24 µg./ml. with the passive haemagglutination test. Red cells treated with formalin before they were tanned and sensitized with antibody could be preserved at − 14° for up to 8 weeks without loss of activity. In experiments with turnip yellow mosaic virus, extracts from healthy plants of eight species tested had little or no effect on either test but concentrated extracts from Chenopodium amaranticolor and Spinacia oleracea plants caused non-specific agglutination of unformalinized red cells, and dilute extracts from Petunia hybrida plants decreased eightfold the sensitivity of the passive haemagglutination test. These effects did not occur with for- malinized red cells. Antibody-sensitized red cells were used in haemagglutination-inhibition tests to determine antiserum titres; antisera to turnip yellow mosaic and raspberry ringspot viruses gave titres 32 times higher than those obtained in tube- precipitin tests.

Serologic cross-reactions of serum antigens associated with acute Plasmodium and Babesia infections.

SummaryAntigens present in the serum during the periods of acute parasitemia of Plasmodium lophurae of ducks, Plasmodium berghei of rats, and Babesia rodhaini of rats were detected by means of gelprecipitation tests and a tube bentonite flocculation (TBF) test, with globulins from sera of animals that had recovered from each of these infections.These antigens, which are associated with globulins, were concentrated by salting with (NH4)2SO4 and ultracentrifugation. Antigens adsorbed to bentonite particles were used in the TBF test to detect and titrate antibody in the sera of animals that had recovered from the respective malarias or babesiosis. In addition to the homologous antigen-antibody reactions it was found that each of the antigens reacted, both in gel-precipitation and in TBF tests, with sera of animals that had recovered from each of the other infections. Sera from normal ducks or rats with a few exceptions did not react with the antigen-bentonite preparations.With bentonite sensitized with globulin from rats recovered from P. berghei and from rats recovered from B. rodhaini, antigens were detected with both materials in the sera of rats with acute P. berghei and rats with acute B. rodhaini infections. Sera from normal rats did not react.On the basis of these observations cross-reacting serum antigens and antibodies are being sought in other erythrocytic infections such as those with Eperythrozoon, Haemobartonella, Anaplasma, and in the sera of human volunteers infected with Plasmodium jalciparum. The TBF test is also being evaluated as a possible serodiagnostic test for latent malaria.

Evaluation of intradermal and serologic tests for the diagnosis of hydatid disease.

SummaryIntradermal tests utilizing an aqueous extract of Echinococcus multilocularis cyst material were performed on 104 individuals living in Uruguay for evaluation of the skin test. In this group, 43 individuals had proven hydatid disease and 61 were normal or had non-hydatid diseases. Antigens containing 0.012 to 0.401 mg N/ml were used. Highest specificity was obtained with skin test antigens which contained 0.012 to 0.015 mg N/ml.Sera from 124 individuals were collected in Uruguay. All but four of the skin-test group were included. Each serum was tested by the indirect hemagglutination, bentonite flocculation and latex agglutination tests. None of the sera in the non-hydatid group reacted in the hemagglutination test and only a few reacted in the bentonite and latex tests. The sensitivity of the serologic tests in patients infected with E. granulosus varied from 82% for serum from individuals with liver cysts to 33–50% for serum from patients with lung cysts.

An evaluation of passive cutaneous anaphylactic reactions with Trichinella and Toxocara antibody-antigen systems.

SummaryThe test for passive cutaneous anaphylaxis (PCA) proved relatively simple and easy to perform. Within limits, the minimal amount of challenge Trichinella antigen was dependent on the amount of antibody used for sensitization. The optimal concentrations of Trichinella and Toxocara antigens to use in PCA tests with these experimental infections were determined. Studies with rabbit and guinea pig antisera indicate that antibodies involved in PCA reactions may differ from those involved in bentonite flocculation or hemagglutination tests. PCA reactions with heterologous antigens are common. The simplicity of the procedure is considered of distinct value and advantageous, but the amount of antigen required for a reaction and the possibility of cross-reactions are drawbacks.

Some Host Responses of Miniature Pigs to Infection with Trichinella spiralis

Using the miniature pig (minipig) as the host animal for Trichinella spiralis, precipitin, skin, and Prausnitz-Kiistner tests indicated the presence of antibodies in antisera although the bentonite flocculation test remained negative when antisera were tested against CDC antigen and the authors' antigen. The CDC Laboratories likewise reported their somatic antigen as giving negative results al- though their metabolic antigen gave titers of 1: 10, 1: 5, and negative, respectively, on the three antisera tested. All minipigs, regardless of infection rate employed, reacted similarly in eosinophilic response, rise in gamma globulin, and serologic reactions. Larval distribution in skeletal muscles followed the pattern reported for normal size hogs and other animals. The miniature pig represents a new host for the study of infection with T. spiralis.

Demographic Aspects in Selecting a Site for a Community Epidemiologic Study

MN THE FALL of 1963, the town of Sudbury, Mass., was selected for a community health study of gout, rheumatoid arthritis, and diabetes. In the selection of a population for this study, some procedures were followed that other investigators might well consider in planning health surveys and community studies. The study was developed to seek solutions to questions related to screening methods and health programs and to provide a continuing source of data on diabetes and arthritis. The fieldwork for the initial coverage of the population has been completed. The resources and objectives of a study usually set broad limits on the choice of a study population. Study objectives may determine the general location, size, and type of the population and whether a sampling scheme or complete coverage is appropriate. Resources influence the number of persons who can be covered, the number of questions or physical tests that may be included, and the length of time allocated to data collection. Once a compromise is reached between purposes of the study and resources available for it, these broad limitations may still leave a wide range of possible sites. The general design of the community health project in which Sudbury was ultimately selected as the community for study called for mailing questionnaires to all residents 15 years and older for them to fill out and mail back. The plan was to invite such residents to make an appointment for a limited physical examination at a central screening point in the town. This examination would include a blood test, a cardiogram, and a brief examination of the skeletal joints by a physician. (Blood determinations were to comprise tests for uric acid, glucose, and serum cholesterol, as well as Bentonite flocculation and sheep cell agglutination tests for the rheumatoid factor.) Additional questions were to be asked the resident during the examination. Confirmatory tests would be given to persons with positive blood tests and private physicians notified when these tests were positive. It was planned to designate a 15 percent sample of the residents over 15 years of age for repeat testing 1 year later. To maximize early results, the community health study was designed so that periods of data collection would be hyphenated by phases of analysis of data.

A RAPID SLIDE TEST FOR THE DETECTION OF VI ANTIBODY IN HUMAN AND ANIMAL SERA.

A rapid slide test for the detection of Vi antibodies, using spheroplasts of Salmonella typhi (Vi I, Bhatnagar strain) as the test antigen, has been described. The spheroplasts, grown in a semisynthetic medium containing 1.5% glycine, maintained their antigenic sensitivity for periods of at least 1 month when stored in the cold in the growth medium preserved with 1:5000 Thimerosal.Comparative tests were carried out with the spheroplast slide technique, agglutination tests using intact Bhatnagar cells and Vi-antigen-sensitized red cells, and flocculation tests of Vi-antigen-sensitized bentonite particles. The slide test proved to be specific and reproducible and was as sensitive as the test tube hemagglutination test for both rabbit and human sera. The intact cell agglutination technique and the bentonite flocculation test were relatively insensitive.

THE BENTONITE FLOCCULATION TEST FOR DETECTION OF PLANT VIRUSES AND TITRATION OF ANTIBODY.

A flocculation test using a highly stable antibody-sensitized bentonite was used to detect plant viruses in both crude and purified preparations. Conversely, antisera could be titrated with bentonite suspensions coated with purified virus. In both systems, the bentonite flocculation test proved rapid, sensitive and specific.

AN EVALUATION OF THE BENTONITE FLOCCULATION AND INDIRECT HEMAGGLUTINATION TESTS FOR THE DIAGNOSIS OF FILARIASIS.

Summary The indirect hemagglutination test and the bentonite flocculation test utilizing a saline extract of Dirofilaria immitis have been evaluated. The test was reactive with sera from individuals with infections of Acanthocheilonema perstans and showed higher titers for symptomatic patients with microfilariae in the blood. In a group of 42 symptomatic patients, 92% of 13 microfilariae-positive patients and 62% of 29 microfilariae-negative patients showed positive serologic tests. In a group of 15 asymptomatic individuals with microfilariae in the blood, 67% were positive. From a group of 295 asymptomatic-microfilariae-negative individuals, 21 sera (7%) were positive. Testing 632 sera from 295 normal missionaries, 84 normal Americans, and 253 individuals with various other parasitic and bacterial infections, an over-all non-specific response of 10% was obtained, utilizing the following criteria for a positive serologic test: (1) a hemagglutination titer of 1:200 or higher with a positive flocculation of 1:5 or higher, or (2) a hemagglutination titer of 1:400 with a negative flocculation reaction. Sera from 141 patients with helminth diseases showed a non-specific rate of 21%. This high rate was due to cross-reactions with trichinosis sera (35%) schistosomiasis (20%) and ascariasis (27%). Since the schistosomiasis and ascariasis sera were from individuals born in an area endemic for filariasis, the reactions may represent a serologic response to past experience with filariasis. Only 5% of 112 sera from individuals with non-helminthic diseases and 5% of 84 sera from normal individuals were positive.

Bentonite, Latex, and Cholesterol Flocculation Tests for the Diagnosis of Trichinosis

AT THE Communicable Disease Center of the Public Health Service the bentonite flocculation test (BFT) is used routinely for the diagnosis of trichinosis. This test has been under continual evaluation for sensitivity and specificity since 1952. As part of this evaluation and to keep abreast of new developments, we have attempted, whenever possible, to compare the BFT with new tests and reagents as they have become commercially available. The trichinalatex antigen sold by Hyland Laboratories has been tested intensively. The antigen for the Suessenguth and Kline flocculation test marketed by the LaMotte Company and the reagents for a bentonite flocculation test and a latex test prepared by the Difco Laboratories have received limited evaluations. The accumulated results of our studies may be of help to local laboratories in interpreting their tests. They do not constitute an endorsement or rejection of the proiducts examined. Several particle agglutination tests have been used for the diagnosis of trichinosis. Suessenguth and Kline (1) adapted the Kline test for syphilis to a test for trichinosis and used cholesterol particles Icoated with various trichina antigens. They reported high sensitivity for both human and animal trichinosis (2-4). Campbell (5) and Coudert and Coly (6) used coated collodion particles, and Leikina and Poliakova (7), carmin particles in their tests. Vogel and co-workers (8) employed cholesterollecithin particles. Bozicevich and associates (9) introduced the use of bentonite particles. A series of papers from the CDC. laboratory has reported evaluations of the bentonite test for detection of infection in pigs (10) and in humans (11). The efficacy of Melcher's antigen (13) and of metabolic antigen (12) has been reported as well as that of lyophilized reagents (14). Innella and Redner (15) were the first to describe the use of latex particles coated with trichina antigen. Their test was essentially a modification of the latex test for rheumatoid arthritis developed by Singer and Plotz (16). Muraschi and co-workers have been using the latex test since 1957 and recently published their evaluation of a slide latex-particle agglutination test for trichinosis (17).

Comparative studies of serologic tests for rheumatoid disease. II. A comparison of the bentonite flocculation test and the sensitized sheep cell agglutination test.

AbstractAgreement was obtained between the bentonite flocculation test (BFT) and the sensitized sheep cell agglutination test (SCAT) in 96 per cent of a random population sample and in 88 per cent of a clinical sample. Rarely, positive results were obtained in either test alone. The BFT was more often positive than the SCAT both in rheumatoid arthritis and in other syndromes.

Diagnosis and treatment of Acanthocheilonema perstans filariasis.

Summary An analysis of 61 patients, 34 known to be infected with Acanthocheilonema perstans and the others presumed to be infected with A. perstans or some other type of filaria, has been made. Seventeen patients exhibited symptoms which are believed to be attributable to A. perstans as microfilariae of A. perstans were demonstrated in their blood and all tested were positive by serologic tests. Fourteen who were symptomatic had no microfilariae in the blood but 12 of 13 tested were positive by serologic tests. Seventeen who were asymptomatic had microfilariae of A. perstans in the blood and all tested by serologic tests were positive. Thirteen were asymptomatic, had no microfilariae in their blood, and 12 of 13 were positive by serologic test. Approximately 50% of the entire group showed symptoms regarded as representing clinical filariasis. Serious symptoms were present in about 9% of the cases. Microfilariae of A. perstans were demonstrable in slightly more than half the cases of both the symptomatic and asymptomatic groups. While unevaluated to date, the serologic tests for filariasis employed in this study (hemagglutination and bentonite flocculation tests) have been useful in arriving at a diagnosis of clinical filariasis. In addition, diethylcarbamazine therapy has in some instances helped clarify the diagnosis of infection with A. perstans through the provocation of symptoms and initial appearance of microfilariae in the blood followed by the resolution of symptoms under treatment. In most instances apparent recovery followed the administration of diethylcarbamazine. Case histories are given illustrating clinical manifestations of infection with A. perstans.

A study of the prevalence of arthritis in alaskan eskimos

AbstractRheumatoid arthritis is present in an Alaskan Eskimo population. The prevalence of X‐ray evidence of osteoarthritis of the hands and wrists has been determined in an Eskimo population. Comparison with available U. S. white data suggests that the prevalence may be lower in the Eskimo. There was a high prevalence of individuals in the village of Wainwright whose sera yielded a positive bentonite flocculation test.

A Study of Bentonite Flocculation Test for Measurement of Type-Specific Streptococcal Antibodies.

SummaryA flocculation test for detection and measurement of type-specific antibody to Group A streptococci has been evaluated. A single strain of each of 3 serological types of streptococcus was employed. When a suspension of bentonite particles between 1.0 and 1.5 μ in size was exposed to an unad-sorbed homologous rabbit antiserum after being coated with partially purified M protein antigen, flocculation was obtained. The highest homologous flocculation titer encountered was 1-32. A weak non-reciprocal cross-reaction between types 36 and 14 M antigens was found: while M antigen of strain S-94 (type 36) did not react with anti-S-23 (type 14) antisera, M protein of strain S-23 exhibited some cross-reactivity with anti-S-94 antisera. The test antigen could be stored at 4°C for at least 6 weeks without loss of potency. No group-specific or type-specific flocculation occurred when the test antigen was prepared by exposing the bentonite particles to a crude antigen mixture, obtained by hot HCl extraction of st...