Indirect Hemagglutination Assay Research Articles

Course of Chronic Trypanosoma cruzi Infection after Treatment Based on Parasitological and Serological Tests: A Systematic Review of Follow-Up Studies.

BackgroundChagas disease is caused by the flagellate protozoan Trypanosoma cruzi (T. cruzi). It is endemic in Latin American countries outside the Caribbean. The current criterion for cure in the chronic phase of the disease is the negativization of at least two serological tests such as enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IIF) and indirect hemagglutination assay (IHA). The serological evolution of treated subjects with chronic T. cruzi infection is variable. Treatment failure is indicated by a positive parasitological and/or molecular test (persistence of parasitemia).ObjectivesTo summarize the pattern of response to treatment of parasitological, molecular and serological tests performed during the follow-up of subjects with chronic T. cruzi infection.MethodsElectronic searches in relevant databases and screening of citations of potentially eligible articles were accomplished. Organizations focusing on neglected infectious diseases were asked for help in identifying relevant studies.Included studies were randomized controlled trials (RCTs), quasi-RCTs, and cohort studies involving adults and children with chronic infection who received trypanocidal treatment (benznidazole or nifurtimox) and were followed over time. The assessment of risk of bias was performed separately for each study design. The Cochrane Collaboration’s tool and the guidelines developed by Hayden et al. were used. Two reviewers extracted all data independently. A third review author was consulted in case of discordant opinion.Additional analyses were defined in ad-hoc basis. Scatter plots for percentage of positive parasitological and molecular tests and for negative serological tests were developed by using the lowess curve technique. Heterogeneity was measured by I2.The protocol was registered in PROSPERO, an international prospective register of systematic review protocols (Registration Number CRD42012002162).ResultsOut of 2,136 citations screened, 54 studies (six RCTs and 48 cohort studies) were included. The smoothed curves for positive xenodiagnosis and positive polymerase chain reaction (PCR) were characterized by a sharp decrease at twelve month posttreatment. Afterwards, they reached 10–20% and 40% for xenodiagnosis and PCR, respectively. The smoothed curves for negative conventional serological tests increased up to 10% after 48 months of treatment. In the long-term, the rate of negativization was between 20% and 45%.The main sources of bias identified across cohort studies were the lack of control for confounding and attrition bias. In general, RCTs were judged as low risk of bias in all domains. The level of heterogeneity across included studies was moderate to high.Additional analysis were incomplete because of the limited availability of data. In this regard, the country of origin of study participants might affect the results of parasitological and molecular tests, while the level of risk of bias might affect serological outcomes. Subgroup analysis suggested that seronegativization occurs earlier in children compared to adults.ConclusionsWe acknowledge that there is a dynamic pattern of response based on parasitological, molecular and serological tests in subjects chronically infected with T. cruzi after treatment. Our findings suggest a trypanocidal effect in the long-term follow-up.Further research is needed to explore potential sources of heterogeneity and to conduct reliable subgroup analysis.

Serological and molecular survey of sheep infected with Mycoplasma ovipneumoniae in Xinjiang, China.

Mycoplasma pneumonia is one of the most important infectious diseases that threaten sheep production. In order to investigate the epidemic status of Mycoplasma ovipneumoniae infection in sheep, indirect hemagglutination assay was used to analyze 1679 serum samples collected from four different breeds of sheep (Kazak sheep, Hu sheep, Merino sheep, and Duolang sheep) in six regions in Xinjiang between 2012 and 2014. One thousand one hundred sixty-nine sheep nasal swabs and 180 lungs were PCR analyzed. The results showed that the average positive rates of the serum samples were 17.75%. The positive rates were between 9.76 and 30.61% in the four breeds. Among them, the Hu sheep had a significantly higher rate than other breeds (P < 0.05). The average positive rates of nasal swabs and lungs were 10.18 and 28.89%, respectively. Based on the phylogenetic trees of 16S RNA gene, the isolates were closest to those strains isolated from inland areas of China, indicating that these epidemic isolates came from the trans-province introductions. Our survey suggests that quarantine is necessary for sheep imported from inland, and effective immunization should be implemented in sheep susceptible to M. ovipneumoniae in Xinjiang, China.

Status of Toxoplasma gondii infection in the etiology of epilepsy

Detection of antibodies to Toxoplasma in sera from patients suffering from recurrent unprovoked seizures were performed using “in-house” indirect hemagglutination assay and by commercially available anti-Toxoplasma immunoglobulin G and immunoglobulin M enzyme-linked immunosorbent assays. Serum antibody to toxoplasmosis were detected in 12.3% and 15.3% by indirect hemagglutination assay and enzyme-linked immunosorbent assays and respectively. Controls showed seropositivity of 5.7% for antibody to Toxoplasma using the same methods. Seropositivity was higher in children compared to adults. No gender differences were noted. Individuals with rural background (living in a relatively unhygienic conditions) were more commonly affected compared to people living in urban areas. (J Pediatr Neurol 2003; 1(2): 95–98).

Severe leptospirosis complicated by Epstein–Barr Virus reactivation

Weil's disease is a severe, potentially fatal illness following Leptospira interrogans infection. The reported case of a patient suffering from acute renal failure, jaundice, thrombocytopenia, rhabdomyolysis and encephalitis syndrome highlights the clinical challenge in reference to Weil syndrome complicated by Epstein-Barr Virus (EBV) reactivation. The diagnosis of leptospirosis was performed using four different diagnostic methods. Sera were analyzed with an in-house IgM and IgG enzyme-linked immunosorbent assay (ELISA) and indirect haemagglutination assay (IHA). Microscopic agglutination test (MAT) was done using 17 reference strains comprising 14 serogroups and 17 serovars. Polyvalent EBV-IgG analysis, EBV-IgG/IgM/IgA western blot analysis as well as quantitative EBV polymerase chain reaction (PCR) were performed. Leptospira IHA showed an initial titer of 1:640 (cut-off 1:320), leptospiral IgG was negative, but IgM was positive. MAT was negative at that time for all 17 strains analyzed. One week later, leptospirosis IHA titer increased to 1:20,480. Leptospiral IgG was now positive, -IgM remained positive and urine was tested negative for leptospiral DNA. The MAT showed positive results for L. interrogans serovar Bataviae, serovar Copenhageni, serovar Pyrogenes and L. borgpetersenii serovar Serjoe. During follow-up examinations, both the leptospiral IgM and IgG remained positive and MAT showed positive results for L. interrogans of different serovars. EBV IgA immunoblot taken at admission was positive for VCA-p18, quantitative EBV-PCR showed an EBV viral load of 2.8E3 copies/ml indicating acute EBV-reactivation. Leptospirosis represents a neglected and re-emerging disease which is difficult to diagnose since Leptospira-PCR from whole blood or urine is frequently negative in the case of early empiric antibiotic treatment. EBV-reactivation might represent a severe complication in Weil's disease which potentially aggravates clinical manifestations of leptospirosis including hepatitis, nephritis, and rhabdomyolysis. Thus, there might be a need for peripheral blood EBV-PCR and EBV blotting in patients suffering from complicated Weil syndrome, also in terms of the choice of antibiotic treatment.

Development of a recombinant OppA-based indirect hemagglutination test for the detection of antibodies against Haemophilus parasuis

An indirect hemagglutination (IHA) test that could detect antibodies against Haemophilus parasuis was developed. The full-length cDNA sequence of the oligopeptide permease ABC transporter membrane protein (OppA) gene was cloned, and inserted into the prokaryotic expression vector pET-30a(+) to construct recombinant plasmid pET-30a-OppA. The recombinant OppA protein was expressed partly in soluble form in Escherichia coli BL21 (DE3) and then purified by Ni2+ column. Furthermore, the recombinant OppA protein was used as an antigen to develop an IHA assay for detecting antibodies against H. parasuis. Results showed that this IHA test could detect species-specific antibodies against H. parasuis. Compared with currently available ELISA, the IHA test had a sensitivity of 85.0% and a specificity of 95.0%. The overall agreement between these two methods was 90.0%. The developed IHA test was used to evaluate the seroprevalence of H. parasuis in Hubei Province, China. The H. parasuis seroprevalence rate ranged from 5.5% to 26.2% in 325 tested clinical serum samples that were collected from three different pig farms in Hubei Province, China. The IHA test developed in this study will greatly contribute to the epidemiological surveys and immunization surveillance of H. parasuis.

Human fascioliasis: a re-emerging disease in upper Egypt.

In recent years, the number of humans infected with Fasciola has risen rapidly. Diagnosis is based mainly on detection of eggs in stool analysis. The rate of infection in Egypt is unknown. In this retrospective study, we describe 23 cases of hepatic fascioliasis, and only 2 of these cases showed eggs in stools. The symptoms of infection, such as pyrexia of unknown origin, epigastric pain, and abdominal distension, were suggestive. Imaging techniques, including abdominal ultrasonography and computed tomography, were very helpful in detecting hepatic changes. An indirect hemagglutination assay proved to be of value for diagnosis. Treatment using a 2-day triclabendazole regimen cured the infection and signs of hepatic involvement disappeared. Combining both imaging techniques and laboratory tests is essential for diagnosis of fascioliasis in the early stage.

Seroprevalence and risk factors of Chlamydia psittaci infection in domestic geese Anser domestica, in Hainan province of China

Chlamydia psittaci, the agent of psittacosis in humans, infects a wide range of bird species. To assess the risk of psittacosis posed by domestic geese in China, the seroprevalence of C. psittaci infection in domestic geese in Hainan province, tropical China was examined using indirect hemagglutination assay (IHA). The overall seroprevalence was estimated at 25.6% (461/1800; 95% CI: 23.6–27.6). The C. psittaci seroprevalence ranged from 19% (95% CI: 14.6–23.4) to 34% (95% CI: 28.6–39.4) among different regions in Hainan province, and the differences were statistically significant (P<0.01). The risk factors significantly associated with C. psittaci seroprevalence were the presence of hygiene conditions, age, gender, and environment of geese in the farms. The results of the present investigation indicated the high seroprevalence of C. psittaci infection in geese in Hainan province, tropical China. Close contact with these geese is associated with a risk of zoonotic transmission of C. psittaci. Public education should be implemented to reduce the risk of avian to human transmission of such a pathogenic agent. To the best of our knowledge, this is the first report documenting the occurrence of C. psittaci seroprevalence in geese in China.

A Prospective Study of Melioidosis After Environmental Exposure of Healthy Participants to Burkholderia pseudomallei During a Muddy Endurance Challenge

In a prospective study of 123 healthy adults competing in a mud-exposing endurance challenge in the melioidosis-endemic tropical north of the Northern Territory of Australia, there were no asymptomatic seroconversions to Burkholderia pseudomallei using indirect hemagglutination assay. However, one competitor developed melioidosis attributable to infection acquired during the event.

Comparison of indirect hemagglutination assay (IHA) and coprological diagnosis of schistosomosis in cows and buffaloes

Schistosomosis is a disease of veterinary and medical importance caused by Schistosoma spp is characterized by frequent diarrhea with blood and mucous, weight loss and weakness in animals and causes significant morbidity, mortality and economic loss in cattle population. The study was designed to analyze/detect the schistosoma spp by coprological and serological examination (IHA) in cows and buffaloes of different areas of Punjab, Pakistan (Lahore, Sheikhupura, Gujranwala and Sialkot) from March 2007- February 2008. Both the techniques (coprological and serological examination (IHA) for Schistosomosis in cows and buffaloes were compared. Overall prevelance of Schistosomosis in cows and buffaloes was noted 14.0% and 13.6% by coprological examination and 17% and 16.3% by indirect hemagglutination assay (IHA), respectively. Statistical analysis showed non-significant difference in indirect hemagglutination assay (IHA) and fecal examination. Similarly month, area, age and sex wise seroprevalence of Schistosomosis was noted higher by IHA test than coprological examination in cows and buffaloes. Sensitivity (%) and specificity (%) of IHA test was noted 100% and >97.0%, respectively. The study reveals that Schistosomosis is prevalent in the study areas and needed proper preventive measure to minimize its prevalence. Besides that it is found that IHA is a good diagnostic tool for detection of Schistosomosis.

Seroprevalence and Risk Factors ofChlamydiaInfection in Domestic Rabbits (Oryctolagus cuniculus) in China

Chlamydia spp. are obligate intracellular bacteria distributed all over the world, known to cause various forms of diseases in animals and humans. In the present study, a serological survey was conducted to detect the seroprevalence and risk factors associated with rabbit chlamydiosis in northeast China, including Liaoning province, Jilin province, Heilongjiang province, and Inner Mongolia Autonomous Region. Antibodies to Chlamydia were determined by indirect hemagglutination assay (IHA). The overall seroprevalence was estimated at 17.88% in total of 800 blood samples. The Chlamydia seroprevalence varied in domestic rabbits from different factors, and genders of domestic rabbits were considered as major risk factors associated with Chlamydia infection. Our study revealed a widespread and high prevalence of Chlamydia infection in domestic rabbits in northeast China, with higher exposure risk in female domestic rabbits. These findings suggested the potential importance of domestic rabbits in the transmission of zoonotic Chlamydia infection, and thus Chlamydia should be taken into consideration in diagnosing rabbit diseases. To our knowledge, there is no report of Chlamydia infection in domestic rabbits in China and the results extend the host range for Chlamydia, which has important implications for public health and the local economy.

Comparative Analysis of Toxoplasmosis in Farm Animals by Indirect Hemagglutination Assay and Enzyme linked Immunosorbent Assay

A sero-prevalence survey of Toxoplasmosis in domestic animals (sheep, goats and camels) was conducted in the Najran region of Saudi Arabia from August to November 2014 to determine the status of the disease, as well as to evaluate the diagnostic performance of the serological tests used. A total of 263 sera were tested, 85 sheep; 88 goats and 90 camels, for the presence of Toxoplasma gondii antibodies using Indirect Hemagglutination test (IHAT) and enzyme-linked immunosorbent assay (ELISA). IHAT showed the higher prevalence of Toxoplasmosis (43.5% in sheep flowed by 31.8% in goats and 24.4% in camels) as compared with ELISA. On the other hand, ELISA showed the higher prevalence of Toxoplasmosis in sheep (45.9%) as compared with IHAT(43.5%). When the data from the IHAT was compared with that of the ELISA test, which was used as a reference test for toxoplasmosis, IHAT had the highest sensitivity (88.1%). It could be concluded that the IHAT and ELISA tests are efficient diagnostic tools for detection and selective diagnosis of Toxoplasmosis. Also high seroprevalence of Toxoplasma gondii in studied animals indicated the importance of these animals as the main source of human infection.

Prevalence of antibodies to Chlamydiaceae in pet dogs in Shenzhen, Guangdong Province, China

The prevalence of chlamydiosis in pet dogs was surveyed in Shenzhen, Guangdong Province, China. A total of 442 serum samples were collected from three districts of Shenzhen, namely the Futian, Nanshan, and Luohu Districts, and assayed for Chlamydiaceae antibodies by indirect haemagglutination assay. The results showed that the mean positive rate was 6.11%, and the positive rate for the Futian District was the highest (9.52%), followed by the Nanshan District (7.08%), and the Luohu District (4.02%). The positive rate for male dogs was 6.08%, and for female dogs 6.16%. Out of all the 38 breeds of dogs examined, 14 breeds were positive. The positive rate for the Cocker Spaniel dog was the highest (14.2%), followed by the Pekinese dog (10.71%), and the Border Collie dog (10.34%). This is the first time that the seroprevalence of Chlamydiaceae infection in pet dogs in Shenzhen, Guangdong province, China was reported, and the results indicated that pet dogs may be an important source for human infection by Chlamydiaceae in Shenzhen and other areas of China.

Comparative Analysis of Toxoplasmosis in Farm Animals by Indirect Hemagglutination Assay and Enzyme linked Immunosorbent Assay

Comparative Analysis of Toxoplasmosis in Farm Animals by Indirect Hemagglutination Assay and Enzyme linked Immunosorbent Assay

Human Schistosomiasis mansoni associated with hepatocellular carcinoma in Egypt: current perspective.

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. It was reported to account for about 4.7% of chronic liver disease in Egyptian patients. The present study aimed at studying the different factors that may be implicated in the relationship of schistosomiasis mansoni with HCC in Egypt. A total of 75 Egyptian patients with primary liver tumours (HCC) were enrolled in this study. They were subjected to full history taking and indirect hemagglutination assay (IHA) for the diagnosis of schistosomiasis. According to the results, the patients were categorized into two groups: Group I: 29 patients with negative IHA for schistosomiasis and hepatitis C virus (HCV) positive with no history or laboratory evidence of previous or current Schistosoma mansoni infection. Group II: 46 patients with positive IHA for schistosomiasis and HCV positive. The significant higher proportion of HCC patients in the present study had concomitant HCV and schistosomiasis (61.3%) compared to HCC patients with HCV alone (38.7%) suggesting that the co-infection had increased the incidence of HCC among these patients. Analysis of the age distribution among HCC patients revealed that patients in Group II were younger in age at time of diagnosis of HCC with mean age 57.1years, as compared to patients in Group I with mean age 64.3years with a highly significant statistical difference between the 2 groups. HCC in Group II was more common in rural residents while it was more common in urban areas in Group I with a significant statistical difference between the 2 groups. Analysis of the sex distribution among the studied groups showed that HCC was more common in males than females in both groups. As regards the aggression of HCC, it was more commonly multifocal and larger in size in patients with concomitant infection than in patients with HCV alone.

Seroepidemiology of melioidosis in children from a remote region of Papua New Guinea.

The Balimo region in Papua New Guinea has previously been identified as melioidosis-endemic with a predilection for children. Where health resources are scarce, seroepidemiology can be used to assess exposure to Burkholderia pseudomallei and therefore risk of acquiring melioidosis. Logistic regression was used to determine associations between indirect haemagglutination assay (IHA) seroreactivity with environmental and demographic/cultural factors to aid in determining risk factors associated with exposure to B. pseudomallei in children. Of the 968 participants, 92.9% (899/968) were children, representing the majority of the community school population in the immediate Balimo region. Of these, 24.6% (221/899) were seropositive. Bathing in the lagoon (OR=2.679), drinking from the well or lagoon (OR=1.474), and being a member of the Siboko (OR=1.914) or Wagumisi (OR=1.942) clans were significantly associated with seropositivity. In the multivariate analysis, drinking from a well or lagoon (OR=1.713), and the Siboko (OR=2.341) and Wabadala (OR=2.022) clans were associated with seropositivity. This study in children supports observations that interactions with groundwater in this region are risk factors in acquiring melioidosis. Public health measures intended to limit this exposure may help reduce the risk of acquiring melioidosis in this remote community. Associations with clan structure may provide more cultural specific insights, however this requires further elucidation.

Evaluation of the role of ATP-binding cassette transporters as a defence mechanism against temephos in populations of Aedes aegypti.

Immunological diagnostic methods for Trypanosoma cruzi depend specifically on the presence of antibodies and parasitological methods lack sensitivity during the chronic and “indeterminate” stages of the disease. This study performed a serological survey of 1,033 subjects from 52 rural communities in 12 of the 18 municipalities in the state of Querétaro, Mexico. We detected anti-T. cruzi antibodies using the following tests: indirect haemagglutination assay (IHA), indirect immunofluorescence assay (IFA), ELISA and recombinant ELISA (rELISA). We also performed Western blot (WB) analysis using iron superoxide dismutase (FeSOD), a detoxifying enzyme excreted by the parasite, as the antigen. Positive test results were distributed as follows: ELISA 8%, rELISA 6.2%, IFA and IHA 5.4% in both cases and FeSOD 8%. A comparative study of the five tests was undertaken. Sensitivity levels, specificity, positive and negative predictive values, concordance percentage and kappa index were considered. Living with animals, trips to other communities, gender, age, type of housing and symptomatology at the time of the survey were statistically analysed using SPSS software v.11.5. Detection of the FeSOD enzyme that was secreted by the parasite and used as an antigenic fraction in WBs showed a 100% correlation with traditional ELISA tests.

Seroprevalence and molecular detection of Mycoplasma ovipneumoniae in goats in tropical China.

In the present study, the seroprevalence and genetic identification of Mycoplasma ovipneumoniae infection in goats were investigated in Hainan Province, tropical China between October 2012 and October 2013. A total of 1,210 serum samples collected from 16 herds in various administrative regions in tropical China were evaluated using indirect hemagglutination assay (IHA). Antibodies to M. ovipneumoniae were tested in (31.7 %, 95 % confidence interval (CI) 29-34.3) 383 of 1,210 serum samples (IHA titer ≥1:16). The M. ovipneumoniae seroprevalence ranged from 26.8 % (95 % CI 20.8-32.9) to 39 % (95 % CI 30.8-47.2) among different regions in tropical China, and the difference was statistically significant (P < 0.01). The seroprevalence of M. ovipneumoniae infection in goats was higher in winter (46.1 %, 95 % CI 39.6-52.5) and spring (33.8 %, 95 % CI 28.3-39.3) than in autumn (27.5 %, 95 % CI 22.6-32.3) and summer (24.7 %, 95 % CI 20.3-29.1), and the difference was statistically significant (P < 0.01). In addition, DNA was extracted from nasal swab; lung samples and the 16S rRNA gene sequences were amplified by polymerase chain reaction (PCR) and then sequenced. Twenty-four of 329 (7.3 %) nasal swab samples and 73 of 280 (26.1 %) pneumonic lung tissues were found to contain M. ovipneumoniae, respectively. The results of the present survey indicate that M. ovipneumoniae infection is highly prevalent in goats in tropical China. This is the first report of the comprehensive survey of M. ovipneumoniae prevalence in goats in China.

Comparison of seven diagnostic tests to detect Trypanosoma cruzi infection in patients in chronic phase of Chagas disease

Objective: To compare the diagnostic performance of seven methods to determine Trypanosoma cruzi infection in patients with chronic Chagas disease.Methods: Analytical study, using the case-control design, which included 205 people (patients with Chagasic cardiomyopathy, n= 100; control group, n= 105). Three enzyme linked immunosorbent assays, one indirect hemagglutination assay and one immunochromatographic test were assessed. Additionally, DNA amplification was performed via the PCR method using kinetoplast and nuclear DNA as target sequences. For the comparative analysis of diagnostic tests, the parameters used were sensitivity, specificity, positive and negative predictive values, Receiver Operator Characteristic (ROC), positive and negative likelihood ratio, as well as κ quality analysis.Results: The commercial Bioelisa Chagas test showed the highest sensitivity (98%), specificity (100%), and positive and negative predictive values; additionally it had the highest discriminatory power. Otherwise, the amplification of T. cruzi DNA in blood samples showed low values of sensitivity (kinetoplast DNA= 51%, nuclear DNA= 22%), but high values of specificity (100%), and moderate to low discriminatory ability.Conclusion: The comparative analysis among the different methods suggests that the diagnostic strategy of T. cruzi infection in patients with chronic Chagas disease can be performed using ELISA assays based on recombinant proteins and/or synthetic peptides, which show higher diagnosis performance and can confirm and exclude the diagnosis of T. cruzi infection. The molecular methods show poor performance when used in the diagnosis of patients with chronic Chagas disease.

Knowledge of, attitudes towards, and practice relating to schistosomiasis in two subtypes of a mountainous region of the People's Republic of China.

BackgroundSchistosomiasis japonica is still endemic in the People’s Republic of China (P.R. China) in five provinces of lake and marshland regions and in two provinces of mountainous regions. Studies elucidated that individual and community perception, attitudes towards schistosomiasis, and hygiene behaviors were crucial factors for preventing schistosomiasis. This study sought to assess the knowledge of, attitudes towards, and practices (KAP) relating to schistosomiasis in two subtypes of a mountainous region in Eryuan County, Yunnan Province, P.R. China. The study’s aim is to make suggestions for establishing more specific and effective control measures for disease transmission and interruption in two subtypes of a mountainous region with low-level infection rates.MethodsA cross-sectional study of 3,000 inhabitants was carried out in the Yongle (plateau basin) and Xinzhuang (plateau canyon) communities of Eryuan County, Yunnan Province in November and December 2011. Stratified cluster random sampling was undertaken using a uniform set of quantitative questionnaires administered by trained assistants. This was further supported with qualitative data from in-depth interviews (IDIs) conducted with ten farmers and ten students. All participants were examined for schistosomiasis using both a serological test (indirect hemagglutination assay [IHA]) and a stool examination (Kato-Katz).ResultsThe total schistosomiasis knowledge rate in Yongle (83.4%) was significantly lower than that in Xinzhuang (95.5%). In both communities, among the respondents aged 15 years or below, more than one third didn’t know the name, endemic areas, and animal reservoirs of schistosomiasis. The majority of respondents in Eryuan acquired their schistosomiasis knowledge from doctors, followed by handouts and hearing from others. The infection rate was once the highest in Yongle, but is now the highest in Xinzhuang, where there are more risk factors for schistosomiasis, such as frequently grazing cattle, digging vegetables or cutting grass in the field, as well as raising cattle by free grazing.ConclusionIn short, Eryuan County’s overall knowledge rate of schistosomiasis was found to be high. Due to various dominating risk factors, different control strategies should be designed keeping in mind the two different subtypes of endemic areas for schistosomiasis in mountainous regions, namely plateau basins and plateau canyons.

Field comparison of circulating antibody assays versus circulating antigen assays for the detection of schistosomiasis japonica in endemic areas of China

BackgroundSchistosomiasis remains a serious public health problem in affected countries, and routine, highly sensitive and cost-effective diagnostic methods are lacking. We evaluated two immunodiagnostic techniques for the detection of Schistosoma japonicum infections: circulating antibody and circulating antigen assays.MethodsA total of 1864 individuals (between 6 and 72 years old) residing in five administrative villages in Hubei province were screened by serum examination with an indirect hemagglutination assay (IHA). The positive individuals (titer ≥20 in IHA) were reconfirmed by stool examination with the Kato-Katz method (three slides from a single stool specimen). Samples of good serum quality and a volume above 0.5 ml were selected for further testing with two immunodiagnostic antibody (DDIA and ELISA) and two antigen (ELISA) assays.ResultsThe average antibody positive rate in the five villages was 12.7%, while the average parasitological prevalence was 1.50%; 25 of the 28 egg-positive samples were also circulating antigen-positive. Significant differences were observed between the prevalence according to the Kato-Katz method and all three immunodiagnostic antibody assays (P-value <0.0001). Similar differences were observed between the Kato-Katz method and the two immunodiagnostic antigen assays (P-value <0.0001) and between the antigen and antibody assays (P-value <0.0001).ConclusionBoth circulating antibody and circulating antigen assays had acceptable performance characteristics. Immunodiagnostic techniques to detect circulating antigens have potential to be deployed for schistosomiasis japonica screening in the endemic areas.