Evaluation of two Toxoplasma gondii serologic tests used in a serosurvey of domestic cats in California

We evaluated the sensitivity (Se) and specificity (Sp) of an IgG enzyme-linked immunosorbent assay (ELISA) and IgG indirect fluorescent antibody test (IFAT) for detection of Toxoplasma gondii-specific antibodies in sera from 2 cat populations using a Bayesian approach. Accounting for test covariance, the Se and Sp of the IgG ELISA were estimated to be 92.6% and 96.5%, and those of the IgG IFAT were 81.0% and 93.8%, respectively. Both tests performed poorly in cats experimentally coinfected with feline immunodeficiency virus and T. gondii. Excluding this group, Se and Sp of the ELISA were virtually unchanged (92.3% and 96.4%, respectively), whereas the IFAT Se improved to 94.2% and Sp remained stable at 93.7%. These tests and an IgM ELISA were applied to 123 cat sera from the Morro Bay area, California, where high morbidity and mortality attributable to toxoplasmosis have been detected in southern sea otters. Age-adjusted IgG seroprevalence in this population was estimated to be 29.6%, and it did not differ between owned and unowned cats. Accounting for Se, Sp, and test covariances, age-adjusted seroprevalence was 45.0%. The odds for T. gondii seropositivity were 12.3-fold higher for cats aged >12 mo compared with cats aged <6 mo.     

Comparative evaluation of antibody positive titer by ELISA and IFA in Theileria annulata vaccinated cattle in Iran

An enzyme linked immunosorbent assay (ELISA) was used to evaluate antibody positive titer in vaccinated and non-vaccinated cattle using schizont infected myeloid cells as an antigen. The result was compared with indirect fluorescent antibody level in the same animals. For this study 116 milking cows, 95 vaccinated and 21 non-vaccinated, were bleeded in order to prepare sera. They were tested with both ELISA and IFA tests. 94 sera had positive antibody titer and 22 sera were negative through ELISA test but, with IFA test, only 89 sera showed positive antibody titer and 27 were negative. Thereby, it was concluded that the sensitivity and specificity of ELISA test in comparison with IFA test was 95.5% and 66.6% respectively. This study generally indicated that ELISA could be an effective test for sero-epidemiological investigations of bovine tropical theileriosis, and it is considered to be valid as an additional test to distinguish the vaccinated from the non vaccinated cattle in order to schedule vaccination programs.     

False-Positive Anti-Toxoplasma Fluorescent-Antibody Tests in Patients with Antinuclear Antibodies

The indirect fluorescent-antibody (IFA) method for diagnosis of toxoplasmosis is widely used and is considered to be as specific as the Sabin-Feldman dye test. After observing a patient with systemic lupus erythematosus (SLE) who had a positive toxoplasma IFA test but a negative dye test, we studied sera with high titers of antinuclear antibodies from 16 SLE patients and from 2 with rheumatoid arthritis for Toxoplasma antibodies in the immunoglobulin G and M (IgG and IgM) IFA tests and the dye test. Results of these tests were compared with titers of antinuclear antibodies, precipitating antibodies to single-strand deoxyribonucleic acid (DNA), and binding antibodies by use of DNA labeled with (3)H-actinomycin D. Of 18 patients, 11 had IgG and 4 had IgM IFA Toxoplasma antibodies; only 2 had antibodies detectable in the dye test. The immunofluorescence patterns in the Toxoplasma IFA test were indistinguishable from those obtained in patients with toxoplasmosis without antinuclear antibodies. Absorption of SLE sera with DNA did not result in a decrease in Toxoplasma IFA titers. When SLE sera were absorbed with live T. gondii, a marked drop in IgG IFA titer was observed as well as a decrease in titers of antinuclear antibodies and (3)H-DNA binding. Treatment of Toxoplasma cells with deoxyribonuclease and ribonuclease did not decrease their fluorescence. These results suggest that T. gondii nuclear antigens can absorb antinuclear antibodies but do not have exposed substrates for deoxyribonuclease. Tests in which organisms containing "nuclear" antigens for IFA detection of antibodies to these organisms are used may result in "false-positives" with sera containing antinuclear antibodies.     

The development of an enzyme-linked immunosorbent assay for Trypanosoma vivax and its use in a seroepidemiological survey of the Eastern Caribbean Basin

An enzyme-linked immunosorbent assay (ELISA) for IgG antibodies against a South American (New World) strain of Trypanosoma vivax was developed and used for mass screening of cattle from 20 islands in the Eastern Caribbean Basin. The sensitivity and specificity of antigens prepared from a bovine-derived field strain and a murine-adapted laboratory strain of T. vivax, both of New World origin, were compared using an indirect fluorescent antibody (IFA) test, and an antigen prepared from the murine-adapted strain was subsequently used to develop an ELISA test. The results of the ELISA test were then compared with the results of a concurrently run IFA test. There was no cross-reactivity with either test using serum from a Trypanosoma theileri-infected cow. Both tests were weakly cross-reactive with sera from a T. brucei-infected steer, and the IFA test was moderately cross-reactive with several serum samples from a T. evansi-infected steer. For bovine sera collected from herds on islands in the Eastern Caribbean region, only five of 640 tested positive with the ELISA test. Thirty five of 653 sera tested were positive by IFA although the fluorescence elicited was weak as compared to that elicited by sera from known infected animals. Sera collected from 27 cattle in a region known to be free of T. vivax (OH, U.S.A) were negative with the ELISA test, whereas seven of 30 sera from a herd in French Guiana known to be infected with T. vivax were positive.(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigation of anti-Toxoplasma gondii antibodies in cats of the Ankara region of Turkey Using the Sabin-Feldman dye test and an indirect fluorescent antibody test

Blood samples from 99 cats from the Ankara province of Turkey were examined for the presence of anti-Toxoplasma gondii antibody with the use of both the Sabin-Feldman dye test (DT) and an indirect fluorescent antibody test (IFAT). Forty of the 99 sera (40.3%) were positive for antibodies against T. gondii with the DT, whereas the IFAT assay detected antibodies in 34 (34.3%). The study also evaluated 3 factors for their potential association with the presence of T. gondii antibody: age (<1 yr, 1-2 yr, and >2 yr), gender (female vs. male), and outdoor access (stray, owned with outdoor access, or indoor only). The DT detected antibodies in 3 cats under 1 yr of age, 22 cats between 1 and 2 yr, and 15 cats older than 2 yr, whereas the IFAT found 1, 18, and 15 cats positive for antibodies, respectively, in each of these categories. Of 61 female cats, 27 (44.2%) were positive by the DT; and of 38 male cats, 13 (34%) were positive by the DT. For the IFAT, 24 female cats (39.3%) and 10 male cats (26.3%) were positive. The percent seropositivity in indoor cats was 30.8% by the DT and 23.1% by the IFAT. In stray cats, the percent seropositivity was 52.8% by the DT and 41.7% by the IFAT. Antibody presence was significantly associated with age, but not with outdoor access.     

Establishment of an enzyme-linked immunosorbent assay for detection of hantavirus antibody of rats using a recombinant of nucleocapsid protein expressed in Escherichia coli.

A recombinant nucleocapsid protein of Hantaan virus (HTN) 76-118 strain expressed in E. coli was applied as a serodiagnostic antigen in an enzyme-linked immunosorbent assay (rHTN-ELISA) for detection of hantavirus antibody in rat sera. The sensitivity and specificity of the rHTN-ELISA were compared with those of the indirect immunofluoresent assay (IFA) using virus-infected cells. The sensitivity of rHTN-ELISA was similar to that of the IFA both in experimentally SR-11 infected rat and naturally infected rat sera. Sera showing a low antibody titer in IFA and suspected to be negative by other methods were also found to be negative in rHTN-ELISA. These results indicate that rHTN-ELISA is effective as a screening method for serodiagnosis of hantaviruses, because of its high sensitivity, specificity, safety and suitability for processing large number of samples.     

Value and Interpretation of Serological Tests for the Diagnosis of Cryptococcosis

MAXIMAL SEROLOGICAL DIAGNOSIS OF CRYPTOCOCCOSIS MAY BE ACCOMPLISHED THROUGH THE CONCURRENT USE OF THREE TESTS: the latex agglutination (LA) test for cryptococcal antigen, and the indirect fluorescent antibody (IFA) and tube agglutination (TA) tests for Cryptococcus neoformans antibodies. These tests were applied to 141 serum and cerebral spinal fluid specimens from 66 culturally proven cases of cryptococcosis and to 42 sera from normal subjects and from patients with other systemic mycotic diseases. The LA test was sensitive and completely specific; of the sera from proven cases, 55% were positive. With the TA test, 37% of the specimens were positive and the test was highly specific. With the IFA test, 38% of the specimens were positive and the test appears to be the least specific of the three. Cross-reactions were most evident with blastomycosis and histoplasmosis case sera. When the three tests were used concurrently, 87% of the cryptococcosis case specimens were positive and permitted a presumptive diagnosis of C. neoformans infections in 61 (92%) of the 66 patients whose specimens were examined.     

A rapid fluorescent focus-inhibition test for determining the neutralizing-antibody response to lymphocytic choriomeningitis virus.

Levels of neutralizing antibody to lymphocytic choriomeningitis (LCM) virus in the sera of 66 infected persons were assayed by a rapid fluorescent focus-inhibition test (RFFIT). The test was more sensitive than the mouse-neutralization (MN) test and could be completed in less than 24 h. The RFFIT titers were compared with titers obtained by the indirect fluorescent-antibody (IFA) and complement-fixation (CF) tests. Neutralizing antibody detected by the RFFIT remained positive after IRA, CF and MN antibodies had disappeared. The RFFIT for detection of LCM antibody is specific and reproducible and seems especially useful for determining the incidence and epidemiology of LCM virus infections.     

Seroepidemiology of Anaplasma marginale in white-tailed deer (Odocoileus virginianus) from Louisiana

Antibodies to Anaplasma marginale were detected by the indirect fluorescent antibody test (IFA) in six of 331 (2%) serum samples of white-tailed deer (Odocoileus virginianus) from Louisiana. None of the serum samples were positive using the A. marginale modified rapid card agglutination test. Of the six IFA positive sera retested by the complement fixation test four sera gave anticomplementary and two gave seropositive reactions. The low A. marginale reactor rate in this white-tailed deer population was probably a reflection of the lack of cohabitation between cattle and deer and the fact that the primary arthropod vectors in Louisiana are tabanids. The validity of the indirect fluorescent antibody test for A. marginale antibodies in white-tailed deer should be evaluated.     

Seroprevalence of Toxoplasma gondii antibodies in cats and pigs from rural Western Amazon, Brazil

Antibodies to Toxoplasma gondii were assayed in sera of 63 cats and 80 pigs from 71 farms located at Rond?nia State, Western Amazon, Brazil, by the modified agglutination test (MAT) and the indirect immunofluorescent antibody test (IFAT). Antibodies (MAT > or = 1: 25) were found in 55 of 63 cats (87.3%) with titers of 1:25 in 2, 1:50 in 2, 1:100 in 7, 1:200 in 1, 1:400 in 2, 1:800 in 9, 1:1,600 in 6, and 1:3,200 or higher in 26 cats. By IFAT, antibodies were found in 55 cats (87.3%) with titers of 1:25 in 2, 1:50 in 1, 1:100 in 4, 1:200 in 4, 1: 400 in 1, 1:800 in 13, 1:1,600 in 12, and 1:3,200 or higher in 18 cats. In pig sera, by MAT, antibodies were found in 30 of 80 pigs (37.5%) with titers of 1:25 in 2, 1:50 in 3, 1:100 in 2, 1:200 in 8, 1:400 in 3, 1:800 in 5, 1:1,600 in 3, and 1:3,200 or higher in 4 pigs. By using the IFAT (titers > or = 1:64), antibodies were found in 35 (43.7%) pigs. The ingestion of undercooked tissues of infected pigs can be a source of T. gondii infection for humans and cats. However, the high seroprevalence of T. gondii in cats from the Amazon seems most likely to be indicative of high contamination of the environment by oocysts.     

New prospects in immunology of toxoplasmosis: skin-tests for control of immunity and immuno-assays and agglutination tests for the detection of specific IgM antibodies

An excretory-secretory (ES) antigen was extracted from supernatants of cell cultures infected with Toxoplasma gondii, purified and controlled according to current standards. In 638 volunteers, the correlation with fluorescent antibody was 94.2% and no false positive skin tests were noted. The skin test did not transform an originally negative serological test into a positive one. For the prevention of congenital toxoplasmosis, this sensitive, specific and inexpensive skin test can be widely used for the detection of immunity to Toxoplasma in women before their first pregnancy. During pregnancy, the detection of specific IgM is very important for the diagnosis of a recently acquired toxoplasmosis and allows for an immediate treatment. For this detection and for the diagnosis of congenital toxoplasmosis, five different serological tests were compared: Indirect Fluorescent Antibody-test (IFA), ELISA test, ELISA test After Capture of IgM (ACCAs), Reverse Enzyme Immuno Assay R-EIA), Double-Sandwich Enzyme Linked ImmunoSorbent Assay (DS-ELISA) and ImmunoSorbent AGglutination Assay (ISAGA). For 37 sera of recently acquired toxoplasmosis, IgM were detected in 98.7% with ISAGA, in 89.5% with DS-ELISA and ELISA in 83% with R-EIA and in 59% with IFA test. The best specificity is obtained with ISAGA, DS-ELISA and R-EIA, from controls with non immune patients (99 cases), patients with chronic toxoplasmosis (77 sera), rheumatoid factors (35 sera) or anti-nuclear antibodies (7 sera). In 21 sera from infants with congenital toxoplasmosis, ISAGA was positive in 13 cases (62%), IFA in 5 cases (24%), ELISA and R-EIA in 2 cases (9.5%) and DS-ELISA in 9 cases (43%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Toxoplasma gondii antibodies in naturally exposed wild coyotes, red foxes, and gray foxes and serologic diagnosis of Toxoplasmosis in red foxes fed T. gondii oocysts and tissue cysts

Antibodies to Toxoplasma gondii were determined in sera from 222 coyotes (Canis latrans), 283 red foxes (Vulpes vulpes), and 97 gray foxes (Urocyon cinereoargenteus) from Indiana, Kentucky, Michigan, and Ohio during 1990-1993. Sera were examined in 1:25, 1:100, and 1:500 dilutions by the modified direct agglutination test (MAT) with formalinized whole tachyzoites plus mercaptoethanol. Antibodies were found in 131 (59.0%) of 222 coyotes, 243 (85.9%) of 283 red foxes, and 73 (75.3%) of 97 gray foxes. Antibodies were also measured by different serologic tests in 4 littermate T. gondii-free red foxes fed T. gondii tissue cysts or oocysts; the fifth littermate fox was not fed T. gondii. Antibodies were measured in fox sera obtained 0, 14, and 36-55 days after infection with T. gondii. All 4 foxes fed T. gondii developed MAT and dye test antibody titers of 1:200 or more 14 days later. The latex agglutination test (LAT) and indirect hemagglutination test (IHAT) were less sensitive than MAT for the diagnosis of T. gondii infection in foxes. Antibodies were not detected by LAT (titer 1:64) in the 2 foxes fed tissue cysts nor by IHAT in 1 of the foxes fed tissue cysts. Toxoplasma gondii was isolated by bioassay in mice from tissues of all 4 foxes fed T. gondii. The control fox had no T. gondii antibodies detectable by any of the serologic tests.     

Characterization of immunoglobulin classes of human antibodies to cryptococcus neoformans

Immunoglobulin G (IgG), immunoglobulin M (IgM) and immunoglobulin A (IgA) levels were determined by radial immunodiffusion techniques in sera from 11 patients with cryptococcosis. Most specimens showed increased levels of IgM. Studies with fluorescein-labeled monospecific antihuman IgG and IgM, however, indicated that IgG was the immunoglobulin reactive in the indirect fluorescent antibody (IFA) test. In addition, cross-reacting sera from mycotic infections other than cryptococcosis were also shown to contain IFA antibodies of the IgG class. Sera treated with 2-mercaptoethanol continued to react in both the IFA test and the tube agglutination test. No correlation could be established between IgG and IgM concentrations and serological reactivity in the sera evaluated in this study.     

Cat scratch disease. Survey on the presence of Bartonella henselae among cats of Tuscany

To verify the presence of Bartonella henselae-infection in cats living in Tuscany (central Italy) serological and bacteriological surveys were carried out. The blood serum samples of 427 cats, 254 living in private houses and gardens and 173 in public or private catteries, were tested for anti-B. henselae antibodies by indirect immunofluorescence assay (IFA). Among these samples, 35 were examined by IFA to detect antibodies against Bartonella quintana. Bacteriological examinations were performed on the blood samples, collected in EDTA (ethylene diaminetetraacetic acid), of 18 cats (10 seropositive to B. henselae and 8 negative). From each of the same 18 specimens DNA was extracted and used as template in polymerase chain reaction (PCR). The primers p24E and p12B were employed in the PCR assay to amplify a 296 bp fragment of the Bartonella 16S rRNA gene. IFA detected 98 (22.95%) B. henselae-positive serum samples (40-40.82% from cats living in houses and gardens and 58-59.18% from cats of catteries) at different antibody titers (70 at 1:64 titer, 4 at 1:128, 22 at 1:256, 2 at 1:512). Among the 35 sera tested to detect antibodies against B. quintana, 9 (25.71%) resulted positive at 1:64 titer; all these samples showed higher antibody titers to B. henselae. Out of the 26 negative sera, 20 were negative to B. henselae too and 6 had antibodies against B. henselae at 1:64. Hemocultures gave negative results. PCR scored positive with DNA of 4 B. henselae-seropositive cats, two of which belonged to two children with cat scratch disease (CSD).     

Specificity of antigens from pathogenic Aspergillus species. I. Studies with ELISA and immunofluorescence

Studies were made by enzyme linked immunosorbent assay (ELISA) and indirect fluorescent antibody (IFA) tests on the reactivities and specificities of 13 antigens prepared from four species of Aspergillus against antisera from immunized rabbits and 64 sera from patients with aspergillosis, other systemic mycoses and nocardiosis. Although reactions in both serological tests were invariably strongest with homologous antigen: antibody systems, antisera from rabbits immunized with A. fumigatus, Blastomyces dermatitidis, Candida albicans and Paracoccidioides brasiliensis reacted in the ELISA test with all of the Aspergillus antigens. In contrast, cross-reactivity was virtually non-existent with antiserum to Histoplasma capsulatum. Of five antigens prepared from A fumigatus tested by ELISA against human sera from patients with aspergillosis and other nocardial and systemic fungal infections, sensitivities varied from 81 to 100% for sera from 32 patients with aspergillosis, and specificities from 20 to 97% for sera from 30 patients with nocardiosis and other systemic mycoses. Purified A. fumigatus C antigen reacted weakly with sera from eight of these 30 patients, but the reactions were readily distinguishable from those obtained with sera from patients with aspergillosis. At optimal serum dilutions, cross-reactivities of A. fumigatus in the IFA studies were non-existent in the sera from 28 patients with candidosis, coccidioidomycosis, cryptococcosis, histoplasmosis, paracoccidioidomycosis and nocardiosis. Sensitivities of IFA were 94% for patients with aspergilloma and 83% for patients with allergic bronchopulmonary aspergillosis.     

Toxoplasmosis III. Studies Using the Complement-Fixation Test and Fluorescence-Inhibition Test with Sera of Experimentally Exposed Birds

The direct, modified direct and indirect complement-fixation tests and the fluorescence-inhibition test were investigated using sera from pigeons, chickens and turkeys which had been exposed to Toxoplasma gondii. The direct CF test was suitable for use with pigeon sera. The indirect CF method effectively demonstrated antibodies in chicken and turkey sera. FI tests were less sensitive than the CF methods.     

Evaluation of indirect fluorescent antibody assays compared to rapid influenza diagnostic tests for the detection of pandemic influenza A (H1N1) pdm09

Performance of indirect fluorescent antibody (IFA) assays and rapid influenza diagnostic tests (RIDT) during the 2009 H1N1 pandemic was evaluated, along with the relative effects of age and illness severity on test accuracy. Clinicians and laboratories submitted specimens on patients with respiratory illness to public health from April to mid October 2009 for polymerase chain reaction (PCR) testing as part of pandemic H1N1 surveillance efforts in Orange County, CA; IFA and RIDT were performed in clinical settings. Sensitivity and specificity for detection of the 2009 pandemic H1N1 strain, now officially named influenza A(H1N1)pdm09, were calculated for 638 specimens. Overall, approximately 30% of IFA tests and RIDTs tested by PCR were falsely negative (sensitivity 71% and 69%, respectively). Sensitivity of RIDT ranged from 45% to 84% depending on severity and age of patients. In hospitalized children, sensitivity of IFA (75%) was similar to RIDT (84%). Specificity of tests performed on hospitalized children was 94% for IFA and 80% for RIDT. Overall sensitivity of RIDT in this study was comparable to previously published studies on pandemic H1N1 influenza and sensitivity of IFA was similar to what has been reported in children for seasonal influenza. Both diagnostic tests produced a high number of false negatives and should not be used to rule out influenza infection.     

Humoral antibody response and Ig characterization of the specific agglutinins in rabbits during experimental American trypanosomiasis

A comparative follow up study of the specific agglutinins detected by direct agglutination (DA) test and the immune response detected by specific lysis (SL), indirect immunofluorescence (IFA), indirect hemagglutination (IHA) and complement fixation (CF) tests in rabbits inoculated with trypomastigotes of T. cruzi is reported here.The specific antibody response was detected first by DA test. Reductive cleavage of sera with 2-mercaptoethanol produced a drop in the agglutinin titer of the sera during the first 30 days of infection.The next test to become positive was SL and later on the IFA, IHA and CF tests became positive simultaneously.When fractions obtained by column chromatography in Sephadex G-200 were tested serologically it was demonstrated that specific antibodies were detected mainly in fraction I (IgM) of the pooled rabbit sera obtained 15 days after inoculation (acute stage), and in fraction II (IgG) of the pooled sera obtained from rabbits 90 days after inoculation (chronic stage).Antigens prepared with trypsinized and formolized epimastigotes of three T. cruzi strains, belonging to each one of the different immunological groups described, worked similarly in the detection of specific agglutinin antibodies.Trypanosoma cruzi agglutinins were highly specific in their reaction with their homologous T. cruzi antigens as was proved by the low agglutinin titer obtained in sera from infected rabbits when, instead of T. cruzi epimastigotes, promastigotes of L. donovani were used as antigen, and by the incapacity of this parasite to absorb the T. cruzi agglutinins.     

Borna disease virus: evidence of naturally-occurring infection in cats in Australia

In Europe, Borna disease virus (BDV) infection has been linked with staggering disease. The aim of this study was serological investigation for BDV infection in Australian cats. De-identified sera were obtained from domestic cats presented at various veterinary clinics. BDV antigen levels were measured by a monoclonal antibody-based ELISA. Antibody to BDV measured semiquantitatively by ELISA was detected in 0.8% of cats from South Australia and 3.2% of animals from NSW Confirmatory assays for ELISA positive samples included Western blot and immunofluorescence assay (IFA) with BDV-specific staining. Seven BDV-antigen positive sera (2.4%) were identified in sera from cats from New South Wales (NSW). In blinded testing, amongst a large number of negative results, repeat submissions over a seven-month period from a cat co-infected with Feline Immunodeficiency Virus (FIV) were BDV-antigen positive. Anti-BDV antibody detected in this cat by ELISA was confirmed by Western blot (p24/ p40/p56) and IFA. For 4 other anti-BDV ELISA-positive samples, specific reactions with BDV proteins were observed by Western blot. Ten other anti-BDV ELISA-positive samples were IFA positive. These data provide consistent serological evidence that, while horses in Australia are free of BDV infection, there may be a low rate of BDV infection in cats.     

Schistosomiasis: Evaluation of the indirect fluorescent antibody,complement fixation,and slide flocculation tests in screening for schistosomiasis

Foreign Service personnel undergo pertinent parasitologic examinations upon return from foreign duty posts. Under this program, 2800 sera have been evaluated for schistosomiasis in this laboratory. The majority of individuals tested were considered to have limited exposure to schistosomiasis, although a few indigenous people from endemic areas also were screened. Nonindigenous populations usually gave stronger serological reactions than did indigenous populations. A comparison was made between those having protozoan and helminthic infections and those that were negative parasitologically. A number of subjects with tissue-phase helminths were evaluated and consistently gave strong reactions in the indirect fluorescent antibody (IFA) tests. On the other hand, there was no characteristic pattern observed in individuals with low serum titers. The IFA test proved to be highly sensitive and sufficiently specific for screening, provided that low background reactions were disregarded (i.e., when +/? and 1+ reactions were ignored at low serum dilutions). Thus, the IFA test was the method of choice for screening. Recourse to the complement fixation (CF) and slide flocculation (SF) tests, however, was necessary for definitive diagnosis. In view of the differences in the antigens and the serodiagnostic technics used in this survey, absolute correlation of test results could not be expected. Nevertheless, the three procedures (IFA, CF, and SF) showed excellent correlation in proven cases of schistosomiasis.