Comparison of the yield of indirect hemagglutination reaction and complement fixation reaction in the diagnosis of neurocysticercosis

Two variations of an indirect hemagglutination test (IHAT) and a complement fixation test (CFT) for the diagnosis of human cysticercosis were compared and evaluated. For the IHAT, a cysticerci crude total saline extract (SE) and a cysticerci lyophylized and delipidized veronal bicarbonate saline buffer (VBS) extract were used, comparing their diagnosis yieldings with that of a CFT in 57 confirmed cysticercosis patients: 45 serum samples and 32 cerebrospinal fluid (CSF). Sera and CSF from 29 patients with other neurological diseases and 25 sera from healthy volunteers were also compared. Both types of methods presented an overall average concordance of 91.5% and 97.0% with CSF and sera respectively. With respect to the sensitivity observed with CFT was 85.2% and 93.3% for CSF and sera, whereas that of IHAT was 96.9% in CSF and 97.8% in sera, when SE antigen was used; with the VBS antigen for IHAT 96.9% and 95.6% were detected in CSF and sera respectively. In order to determine the specificity of the IHAT, besides the study in healthy volunteers, in patients with other neurological diseases and in 156 serum samples from individuals with other parasitoses, such as hydatidosis (43), trichinosis (56), fascioliasis (31) and Chagas' disease (26) were also tested. A high reactivity with the hydatidosis group was found. The specificity, using a titre > or = 1:16 as a diagnostic value and without considering hydatidic sera was 99.4% for RHAI (SE), 100.0% for RHAI (VBS). The use of IHAT and CFT in diagnosis of human cysticercosis is discussed.     

Use of the indirect hemagglutination test for the study of ornithosis. Report 2. Preparation and approbation of the dry ornithosis erythrocyte diagnostic agent

An original preparation--dry ornithosis erythrocytic diagnostic agent for the indirect hemagglutination test was prepared on the basis of formalinized tannin-treated sheep red blood cells and group-specific phospholipid antigen of the causative agent of ornithosis. This diagnostic agent retained its specific activity for 18 months (observation period). The use of this preparation considerably facilitated the method of performance of this test, this offering a possibility of its wide application in practice. A sufficiently high sensitivity and specificity of the indirect hemagglutination test with the suggested diagnostic agent, in comparison with the complement fixation test was demonstrated.     

The indirect hemagglutination reaction in the diagnosis of trichinosis

An indirect hemagglutination test (IHAT) for trichinosis using a Melcher's antigen was evaluated and compared with a precipitin test (PT) and a bentonite flocculation test (BFT). One hundred and forty eight serum samples from patients from the whole country confirmed or suspected to have trichinosis by clinical or epidemiological evidences were studied: 117 (79.1%) samples resulted positive by IHAT, 138 (93.2%) by PT and 65 (43.9%) by BFT. Sixty three serum samples from patients with strong clinical suspect of trichinosis presented the PT and the BFT positive and were compared with the IHAT for sensitivity study. IHAT was positive in 60 (95.2%) serum samples. In order to determine the specificity of IHAT 25 serum samples from healthy volunteers and 124 serum samples from individuals with other parasitoses, such as cysticercosis (48), hydatidosis (45) and fascioliasis (31) were studied. The specificity, using a titre > or = 1:16 as a possible diagnostic value was 96%. The use of IHAT with RP and BFT in the diagnosis of human trichinosis is discussed.     

Prevalence of ornithosis in the Lithuanian SSR

As a result of immunological examination of 658 domestic ducks of 6 poultry farms and 269 doves caught in Vilnius, antiornithosis antibodies were revealed in 3.1 +/- 0.7% of ducks and in 36.4 +/- 2.9% of doves. They were also found in 20 of 34 wild waterfowl. The causative agent of ornithosis was isolated in virological examination of the organs of a coot. Ornithosis nature of an epizootic outbreak among ducks of a poultry farm was proved by virological examination. The population was examined immunologically (2285 persons) and by intradermal test with the ornithosis antigen (80 persons). Positive specific reactions were revealed in 32.6% of persons engaged in poultry tending, and in 7.6% of other rural population. A case of ornithosis in man engaged in fowling (of doves) for their examination is described.     

Purification and characterization of E. histolytica antigen for diagnosis of amoebiasis

Entamoeba histolytica soluble crude antigen was fractionated by gel filtration on Sephacryl S-300 into four fractions, viz. F1(669 kDa); F2(51.2 kDa); F3(25.1 kDa) and F4(10.5 kDa). F1 fraction was observed to be more sensitive and specific for the detection of antibody in amoebiasis than the crude and other fractions of purified antigens employing IHAT and ELISA. ELISA was found to be better than IHAT since it could detect antibody in the sera (3/6) of asymptomatic cyst passers. The cross reaction of crude antigen with toxocariasis (1/4) and toxoplasmosis (2/5) sera were associated with F4 fraction. F3 and F4 were having low molecular weight and were not sensitive in detection of antibody in amoebiasis. Biochemical characterization revealed glycoprotein nature of the specific (F1) antigen fraction.     

Experimental dicrocoeliasis: the humoral immune response of golden hamsters and rabbits to primary infection with Dicrocoelium dendriticum

The results presented deal with the humoral immune response of golden hamsters to primary experimental infection with D. dendriticum. The development of serum antibodies has been comparatively investigated with three hamster groups (n = 43) harbouring different burdens of adult flukes. The mean numbers of parasites were 11, 30, or 130 per animal. Serum antibody response was studied during an observation period of at least 331 and up to 496 days postinfection. For antibody detection the sensitivities of precipitation test (PTs) (double diffusion test, immuno- and counterimmunoelectrophoresis), of the indirect haemagglutination test (IHAT), the complement fixation test (CFT), and the enzyme linked immuno sorbent assay (ELISA) were compared using aqueous crude fluke antigen and crude egg antigen. CFT and ELISA were most sensitive for the early detection of initial response. Thereafter all the tests employed revealed increasing antibody titres, which in general remained at constant levels and persisted until the end of the observation period with the exception of CF-antibodies. In general fluke antigen was found to be more sensitive than egg antigen. However, in CFT this antigen occasionally has been associated with unspecific inhibition of haemolysis. Comparison of the results shows that ELISA using crude fluke antigen gave the most realistic picture of the actual fluke burden. Also preliminary results on the precipitin response of rabbits (n = 3) after primary experimental exposure to different numbers of metacercariae (500, 1,000, and 3,000 per animal respectively) are reported. Employing the above mentioned PTs a persisting antibody response could be demonstrated only after exposure to at least 3,000 infective larvae. The initial response was found on day 63, the observation period was 550 days.     

Epidemiology of toxoplasmosis in Chile. VI. Prevalence of human infection, investigated by means of an indirect hemagglutination test, in regions VII, VIII and IX

In presecuting the investigations on the epidemiology of toxoplasmosis in Chile, a new series of serological surveys has been performed during 1982-1989 in 10 urban and 25 periurban-rural localities from the regions VII, VIII and IX of the country (34 degrees 41'-39 degrees 38' South lat.). In 9,758, randomly selected apparently healthy persons, and indirect hemagglutination test (IHAT) for toxoplasmosis was carried out. The age of these individuals (4,203 males and 5,555 females) varied between 4 and 84 years. The examined persons represent a 0.33% of the total population of the three studied regions. IHAT titers of 1: > or = 16 were regarded as positive. The global prevalence for positive IHAT was 45.5% (50.5% in men and 41.7% in women). A higher proportion of positive tests was observed in urban areas (47.0%) than in periurban-rural sections (33.3%). An increasing prevalence with age was also observed. Only 5 (0.05%) persons had IHAT titers higher than 1:1000.     

Common antigen between coxsackievirus A 16 and enterovirus 71.

Cross immunofluorescence revealed that coxsackievirus A 16 (CA 16) shared a common antigen with enterovirus 71 (E 71). The cross reactivity of these two serotypes was also examined by complement fixation test with purified virus preparations fractionated by sucrose density gradient centrifugation and two peaks of antigenicity were detected, one being type-specific and the other cross-reacting. The common antigen was heat-stable and attributable to empty capsids. Immuno-diffusion also revealed the common antigen. Infants without antibody to E 71 developed complement fixing and precipitin antibody to E 71 after recovery from hand, foot and mouth disease caused by CA 16.     

Use of the indirect hemagglutination reaction in studying ornithosis infection. III. The diagnostic value of the IHR with an ornithosis erythocytic diagnosticum]

In both experimental and clinical conditions the passive hemagglutination test (PHAT with the use of an ornithosis erythrocytic diagnostic preparation was found to be sufficiently sensitive and specific as compared with the complement fixation test (CFT), a routine testing method. The study of the dynamics of immune response in infected animals and ornithosis patients allowed to regard the PHAT as a comparatively early method of serological analysis. Hemagglutinins were also found to circulate in the patients' blood sera only for a short time (on the average for 1 1/2--2 months). The CFT and the PHAT with erythrocytic diagnostic preparation, used in combination, will make it possible not only to diagnose ornithosis in patient more effectively, but also to differentiate between the cases of infection and anamnestic reaction.20     

Secretory expression of E2 main antigen domain of CSFV C strain and the establishment of indirect ELISA assay

The sequence encoding an E2 main antigen glycoprotein of the C strain of classical swine fever virus (CSFV) was highly expressed in the host cell E. coli BL21-CodonPlus (DE3)-RIL using the pGEX-4T-1 expression vector and the soluble recombinant product was purified with Glutathione Sepharose TM<'4B> by centrifugation. The soluble recombinant protein showed good immune reactions and was confirmed by Western blot using anti-CSFV-specific antibodies. Then an indirect ELISA with the purified E2 protein as the coating antigen was established to detect antibody against CSFV. The result revealed that the optimal concentration of coated antigen was 0.6 μg/well and the optimal dilution of serum was 1:80. The positive cut-off value of this ELISA assay was OD<,tested serum>/OD<,negative serum>≥2.1- The E2-ELISA method was evaluated by comparison with the indirect hemagglutination test (IHAT). When a total of 100 field serum samples were tested the sensitivity and specificity were 90.3% and 94.7% respectively. Specificity analysis showed that there were no cross-reactions between BVD serum and the purified E2 protein in the E2-ELISA.     

Results of serological reactions in patients with presumptive diagnosis of toxoplasmosis]

Even though Toxoplasma gondii is an ubiquitous parasite that can effect most of human structures and organs, not all clinical manifestations suggestive of being produced by it are caused by this protozoon. For these reasons sera samples of patients suspected of having toxoplasmosis are sent to the laboratory for detecting specific antibodies which would facilitate the differential diagnosis. Thus, 716 sera from suspected patients, mainly from the Metropolitan Region of Chile, were sent to the Parasitology Laboratory of Chile University in order to carry out in them, specific serological tests for toxoplasmosis: indirect hemagglutination test (IHAT), Sabin Feldman reaction (SFT) and complement fixation test (CFT). Were considered positive: IHAT and/or SFT with titers > or = 1:16 and CFT with titer > or = 1:5. The pathologies for demanding these serological tests were obstetrical problems 210 (29.3%), congenital problems 193 (27.0%), ophthalmopathies 81 (11.3%), adenopathies 77 (10.8%), AIDS 67 (9.4%), myocardiopathies 46 (6.4%) and miscellaneous 42 (5.9%). The positivity found in these sera was higher in ophthalmopathies (61.7%), followed by obstetrical problems, miscellaneous problems, myocardiopathies and AIDS (50.7-52.4%), less frequent was the positivity in adenopathies (35.1%) and congenital problems (23.1%). In general, the 43.7% of positivity for toxoplasmosis found in these patients is higher than the 37.0% found in the general population. High titers of IHAT and SFT plus positive CFT was found in 13-fold higher proportion than in the general population.     

Chagas disease in the Chilean altiplane. Epidemiological, parasitological, and clinical aspects]

Chagas' disease is endemo-enzootic in periurban and rural sections of the first seven (18 degrees 30'-34 degrees 36' South lat.), out of the thirteen political-administrative regions of Chile. Permanent inhabited localities situated at different altitudes over the sea level (OSL) are classified in: coastal settlement (0-1,499 m OSL), intermediate settlement (1,500-3,000 m OSL) and altiplano settlement (> 3,000 m OSL). A total of 1,558 dwellings and their occupants from regions I and II were surveyed in 1982-1984 for different epidemiological Trypanosoma cruzi infection parameters. Hence, 261 dwellings, 189 domestic mammals and 517 people (ages 5- > or = 60 years) from the Altiplano settlement were studied. The results obtained were: 4(1.5%) and 2(0.8%) of dwellings infested with Triatoma infestans, according to occupants information and by observation of direct evidences respectively; 8(4.2%) animals (1 dog, 4 goats and 3 sheep) with a positive hemagglutination test (IHAT) for Chagas' disease; 21 people (4.1%) with a positive IHAT; 4(19.0%) and 3(14.3%), out of the 21 IHAT positive individuals with all types of electrocardiogram (EKG) abnormalities and EKG abnormalities suggestive of a chagasic etiology respectively, whereas 65(13.1%) and 15(3.0%), out of the 496 IHAT negative ones presented the same kinds of EKG abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)     

Electrocardiographic alterations in persons with a positive serology for toxoplasmosis]

To each of 11,161 randomly taken people from urban and peri-urban localities of the first seven regions of Chile (geographic area of distribution of Chagas' disease in the country), with negative serology for Chagas' disease, an indirect hemagglutination test (IHAT) for toxoplasmosis and an EKG were practiced. The IHAT for toxoplasmosis resulted positive in 3,519 individuals (31.5%). The EKG showed alterations in 10.9% of the IHAT positive individuals and in 7.9% of the IHAT negative ones. This difference between the proportion of altered EKG in IHAT positive people and altered EKG in those with negative IHAT is statistically significative with p < 0.001. These results suggest the convenience of considering toxoplasmosis as a cause of chronic myocardiopathy in epidemiological studies on Chagas' disease, since not discard the presence of Toxoplasma gondii infection should overvaluete the magnitude of the impact of Trypanosoma cruzi in the genesis of such a myocardiopathy.     

A sensitive method for detecting the fermentation-inhibition antibody to Mycoplasma pneumoniae.

The fermentation-inhibition (FI) test for Mycoplasma pneumoniae was improved by using a combination of guinea pig complement and gamma globulin-depleted horse serum in place of unheated whole horse serum employed in the conventional assay system. As the test antigen for the new FI assay system, M. pneumoniae filtrated through a 3.0 microns membrane filter was used. Owing to the strong augmenting effect of guinea pig complement, the FI activity of rabbit immune serum was increased 32-fold in the new system compared with the conventional system. Furthermore, IgM antibody, which is barely detectable by the conventional system, could easily be titrated by the new system. With this sensitive method, rapid rise of FI titer was clearly demonstrable in most children with acute M. pneumoniae infections, and a prevalence of FI or growth-inhibitory antibody among healthy adults in Japan (82%) was revealed.     

An outbreak of ornithosis at a textile factory

For the first time an outbreak of ornithosis at a textile factory is described. The data on the specific epidemiological features of the outbreak, the specific clinical features of the disease, the results of catamnestic observations and the study of the titers of specific antibodies in the complement fixation test are presented.     

The application of a protein fraction derived fromTreponema Pallidum (reiter strain) as an antigen in the serodiagnosis of syphilis

Summary A comparison was made between the complement fixation test using a protein fraction derived fromTreponema pallidum (Reiter strain) as an antigen and theTreponema pallidum immobilization test. As appears from the results obtained with 116 syphilitic and 137 presumably non-syphilitic sera the complement fixation test with protein antigen showed an excellent sensitivity together with a satisfactory specificity.     

Household chagasic endemia detected as a consequence of a case of congenital infection]

During a study on prevalence of parasitic and viral serological markers in pregnant adolescents, a 17-year-old primipara from Polpaico, village near Santiago, gave birth to a normal male newborn in a Santiago hospital. As both of them presented positive an indirect hemagglutination test (IHAT) for Chagas' disease and the corresponding xenodiagnosis (XD), the infection in the infant was considered to be acquired through the placental route. According to recent epidemiological surveys Polpaico is an endemo-enzootic chagasic rural settlement, where 14.7% of dwellings were infested with Triatoma infestans, while triatominae, persons and domestic mammals were found infected with Trypanosoma cruzi. One month later the adolescent mother, her son and other 11 consanguineous members of the family were visited in their homes in order to submit each of them to a physical examination and to IHAT for Chagas' disease, and XD to those whose IHAT resulted positive. Thus, in 7 (53.8%) the IHAT was positive and in 4 (57.1%) out of these 7 presented positive the XD, results that as a whole yielded a household chagasic endemics.     

Verification of tween-ether antigen for complement fixation test in the diagnostics of toxoplasmosis

Tween-ether toxoplasma antigen for the complement fixation test was verified on a more extensive clinical material. From a series of 949 patient's sera, positive reaction was obtained in 44% of samples with the tween-ether antigen and in only 33.5% of samples with the FT antigen. All sera, giving positive results only with the tween-ether antigen, were also positive in the Sabin-Feldman test. The authors believe that by using this type of more sensitive antigen, containing also the cell-wall components of Toxoplasma gondii, it would be possible to standardize serological examination by the complement fixation test on the basis of an international standard serum.     

Epidemiology of toxoplasmosis in Chile. V. Prevalence of the infection in humans and domestic and wild animals, studied by indirect hemagglutination reaction, in the Juan Fernández Archipelago. V Region

A serological study utilizing an indirect hemagglutination test (IHAT) for toxoplasmosis was carried out in 222 humans and in 58 domestic animals (31 dogs, Canis familiaris; 27 cats, Felis catus), and in 62 wild mammals distributed into 50 rabbits, Oryctolagus cuniculus and 12 goats, Capra hircus. This survey was performed in the Juan Fernández Archipelago, formed by three islands: Robinson Crusoe, Santa Clara and Alejandro Selkirk (80 degrees 47'-78 degrees 47' west long., and 33 degrees 36'-33 degrees 47' south lat.). Blood samples were collected in filter paper and IHAT with titres greater than or equal to 1:16 were considered positive. This survey showed a prevalence of 42.3% in humans with no difference between men (43.0%) and women (41.5%). A high prevalence was found within groups of young individuals (0 to 19 years old), men and women. Regarding the domestic animal population, 44.8% resulted positive, distributed as follows: dogs 9.7% and cats 85.2%. Twenty one percent of wild animals were positive, distributed as follows: rabbits 8.0% and goats 75.0%. The global prevalence of toxoplasmosis in animals (domestic and wild) was 32.5%. All titres in humans and animals were less than or equal to 1:512. Toxoplasmosis is well extended among the human and animal population of the Juan Fernández Archipelago.     

Soluble Antigens for Immunofluorescence Detection of Histoplasma capsulatum Antibodies

Soluble antigens from Histoplasma capsulatum in the mycelial and yeast phase were purified by gel filtration, fixed onto paper discs, and employed in an indirect immunofluorescence procedure to detect antibody in sera from individuals infected with H. capsulatum. The elution patterns of crude histoplasmin passed through Sephadex G-200 revealed two minor peaks of protein showing immunofluorescence, complement fixing, and precipitating-antigen activity. A large peak containing the pigment and other low molecular weight materials showed no serological activity. A polysaccharide antigen obtained from fragmented, deproteinized yeast-phase cells was reactive in the fluorescent-antibody test but showed no antigen activity in complement fixation or precipitin tests. Although certain sera from culturally proven cases of blastomycosis, coccidioidomycosis, and cryptococcosis reacted with the purified Histoplasma antigens, preliminary evaluation indicated that the immunofluorescence technique may be of value as a screening procedure for the serodiagnosis of histoplasmosis.