Serum antigen and antibody detection in echinococcosis: application in serodiagnosis of human hydatidosis

Human and camel cystic echinococcosis - a polyclonal antibody-based sandwich ELISA for its serodiagnosis with molecular identification

Cystic echinococcosis (CE) is an emergent neglected disease affecting human and animals in Egypt with a wide distribution and incidence. This study aimed to evaluate the use of a polyclonal antibody-based sandwich ELISA in the detection of Echinococcus granulosus antigen in human and camel sera. Hydatid cyst protoscoleces antigen (PsAg) was isolated from hydatid cysts collected from naturally infected camel livers and lungs. PsAg was used for immunization of rabbits to raise IgG polyclonal antibodies (IgG PsAb). IgG PsAb were then precipitated, purified using Protein-A Sepharose gel and labeled with horseradish peroxidase enzyme. We assayed the purity of the IgG PsAb, and the two prepared E. granulosus antigens CPsAg from camel cysts and HPsAg from human cysts by Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The resulted protein bands of the prepared CPsAg appeared at different molecular weights: 180, 90, 68, 54, 42 and 22 kDa while, HPsAg shared with it in 4 common bands at 68, 54, 42, and 22 kDa. The purified IgG PsAb had been resolved at two bands at 52 kDa and at 32 kDa. Sandwich ELISA were performed for the detection of circulating E. granulosus antigens in sera of human (n = 183) and camels (n = 190). The purified IgG PsAb showed strong reactivity against E. granulosus infected human and camel samples and no cross reactivity neither with free-healthy negative sera nor with others parasitic diseases (Schistosomiasis, Fascioliasis, Toxoplasmosis, Ancylostomiasis for human samples and Fascioliasis, ticks' infestation, Eimeriosis, Cryptosporidiosis, Nasal myiasis, Toxoplasmosis for camel samples). The sensitivity of the assay was 98.25% (56/57) and 96.9% (31/32) against human and camel samples, respectively. Specificity was 100% in both human and camel samples. Sandwich ELISA detected CE in 33.3% (24/72) and 55.6% (50/90) random human and camel samples, respectively. Indirect ELISA, using CPsAg, was used for detection of antibodies in positive human and camels' sera and detected 96.5% (55/57) and 93.8% (30/32) of human and camel samples, respectively. In our study, Genomic DNA was extracted from protoscoleces fluid of human liver hydatid cysts to identify the Echinococcus sp. isolate based on NADH dehydrogenase subunit 1 (NAD1) gene by Polymerase Chain Reaction (PCR) and the isolate (GenBank: OP785689.1) were identified as E. granulosus sensu lato genotype. In conclusion, Sandwich ELISA technique was found to be a potent and sensitive assay for detection of hydatid antigen in both human and camel samples.

Intramuscular hydatid cyst of paraspinal muscle: A diagnostic challenge

Hydatid cyst is a zoonosis caused by ingestion of eggs of Echinococcus-a tapeworm. Following ingestion of the eggs, oncosphere larvae are released which penetrate the intestinal wall to invade various organs of the body including liver, lungs, and skeletal muscles via. blood vessels. Due to their contractile nature and high lactic acid content, skeletal muscles are typically not a suitable site for attachment of hydatid cyst. In our case report presented below, we report a rare case of an isolated hydatid cyst of paraspinal muscle presenting as a slow-growing asymptomatic mass in the back, posing a clinical diagnostic dilemma.

Determination of echinococcosis IgG antibodies using magnetic bead-based chemiluminescence immunoassay

Echinococcosis is a kind of parasitic disease shared by humans and animals. The aim of this study was to establish a new detection method for echinococcosis screening using magnetic bead-based chemiluminescence immunoassay (CLIA). A magnetic bead-based CLIA to determine anti-echinococcosis IgG antibodies was optimized and established. The sensitivity, accuracy, precision and recovery rate were evaluated using the national reference serum, and the reference interval, specificity and comparison assays were performed using the clinical negative/positive echinococcosis serum samples. This study established a new CLIA to determine anti-echinococcosis IgG antibodies. The sensitivity of this CLIA method was higher than that of the registered ELISA kit and the national standard, the conformance rate of the negative/positive references was 100% (8/8), the CVs of the sensitivity reference were all below 5%, and the CVs of the precision reference were 5.7%. There was no obvious cross-reactivity with the common parasitic disease-positive serum and serum interferents. Clinical sample testing found that the cutoff value of this CLIA was 5537.15 (RLU), and there was no significant difference between the CLIA method and the registered ELISA kit. This study established a fully automated CLIA method with high sensitivity, specificity, accuracy, precision, recovery rate, and satisfactory clinical testing performance, which may provide a new choice for echinococcosis screening.

A Novel Designed Sandwich ELISA for the Detection of Echinococcus granulosus Antigen in Camels for Diagnosis of Cystic Echinococcosis

Echinococcus spp. are important cosmopolitan zoonotic parasitic tapeworms that cause a disease called hydatidosis or cystic echinococcosis (CE), which has remarkable economic losses. The objective of our study was to develop a specific IgG polyclonal antigen-based ELISA (Sandwich ELISA; capture ELISA) method for the detection of circulating Echinococcus granulosus (E. granulosus) antigens in camels infected with hydatid cysts before slaughtering and its application in serodiagnosis of CE in animals to assess the positive rate of hydatidosis in camels slaughtered in Giza governorate abattoirs in Egypt. In this study, molecular identification of Echinococcus sp. isolate was performed based on the NADH dehydrogenase subunit 1 (NAD1) gene, revealing the isolate (GenBank: OQ443068.1), which is identical to the G6 E. granulosus sensu lato genotype. The positive rate of hydatid cysts was determined in slaughtered camels' organs (n = 587). The results revealed that hydatid cysts were found in 46.5% (273/587) of the examined camels. Pulmonary echinococcosis was significantly more prevalent in the slaughtered camels (60%, 164/273) than hepatic echinococcosis (39.9%, 109/273), (p = 0.001, Chi Square = 11.081). Cyst fertility rates were higher in hepatic (90.8%, 99/109) than in pulmonary cysts (83.5%, 137/164) and the most viable protoscoleces were recorded from fertile the hepatic cysts (67.85 ± 12.78). In this study, hydatid cyst germinal layer antigen (GlAg) was isolated and used for the immunization of rabbits to raise IgG polyclonal antibodies (anti-Echinococcus GlAb IgG). These IgG polyclonal antibodies were purified by affinity chromatography using a protein A column, then labeled with horseradish peroxidase. Electrophoretic analysis of IgG polyclonal antibodies and crude GlAg was performed in 10% polyacrylamide gels. The SDS-PAGE revealed four bands at molecular weights of 77 kDa, 65 kDa, 55 kDa, and 25 kDa. The Sandwich ELISA was performed to evaluate the sensitivity and specificity and cross-reactivity of the prepared IgG polyclonal antibodies. The circulating hydatid antigen was found in 270 out of the 273 samples with hydatidosis, with a sensitivity of 98.9% (270/273), a specificity of 94.9% (296/312) and a diagnostic efficacy of 96.8%. Regarding the cross reactivity, anti-Echinococcus GlAb IgG showed a low cross-reactivity with Fasciola gigantica infected camel sera (3/8), and Myiasis (Cephalopina titillator larvae; 3/20). No cross-reactivity was recorded with uninfected camel sera (negative sera for E. granulosus), and no cross-reactivity was found with antigens of Eimeria spp., Toxoplasma gondii, Cryptosporidium sp., and Hyalomma dromedarii (ticks' infestation). Then, Sandwich ELISA was conducted again to detect E. granulosus antigen in all the collected camel sera, which resulted in a 48.7% (286/587) positive rate of CE compared to 46.5% (273/587) using a postmortem inspection (PM diagnosis) (p = 0.5, Chi Square = 0.302). In conclusion, the Sandwich ELISA technique introduced in this study appears to be a sufficiently sensitive diagnostic assay for the detection of camels' echinococcosis using anti-Echinococcus GlAb IgG. In addition, it might offer a significant medical and veterinary importance in helping the early detection of hydatidosis, as well as its early treatment.

Molecular characterization and serodiagnostic evaluation of the Echinococcus ortleppi recombinant glutaredoxin 1 protein for cystic echinococcosis in buffalo (Bubalus bubalis)

Cystic echinococcosis (CE), caused by the metacestode of Echinococcus granulosus sensu lato (s.l.), adversely affects the physiology of the vital organs in which they grow. Condemnation of meat causes substantial economic loss to the livestock industry. Conventionally the infection is detected by necropsy as serological diagnosis of the infection in livestock is ambiguous. Identification of specific diagnostic antigens would be a substitute for the cyst fluid antigens which lack adequate diagnostic sensitivity and specificity. BLAST analysis supported by the negligible pairwise nucleotide distance of the 389 nt COX1, 489 nt NAD1, and 425 nt ITS1 with the related sequences of E. ortleppi ascertained the association of E. ortleppi with CE in buffaloes. Given the extensive distribution of glutaredoxin 1 in every developmental stage of Echinococcus granulosus s.l that makes it an ideal serodiagnostic antigen for CE, we expressed the 14 kDa E. ortleppi glutaredoxin 1 (rEoGrx1) protein in E. coli BL21 (DE3) and tested a total of 225 sera samples, including 126 sera samples from the necropsy-positive buffalo, by the rEoGrx1 IgG-ELISA. The ELISA could detect a total of 82/126 sera samples as positive. The diagnostic sensitivity and specificity of the rEoGrx1 IgG-ELISA were 65.1 % and 51.5 %, respectively. The protein showed serological cross-reaction against Fasciola gigantica, Toxoplasma gondii, and Sarcocystis sp. The in silico bioinformatics analysis of the E. ortleppi, F. gigantica, and T. gondii glutaredoxin sequences revealed fully conserved amino acids at positions 11 and 21, the substitution of conserved amino acids at positions 14 and 6, and semi-conserved substitutions at positions 3 and 4, respectively. The findings partly explain the molecular basis of the serological cross-reactivity of the protein.

Basic Operative Tactics for Pulmonary Echinococcosis in the Era of Endostaplers and Energy Devices

Human echinococcosis is a zoonotic infection caused by the larvae of the tapeworm species Echinococcus. The liver is the most common location for a primary echinococcosis. However, the parasite may bypass or spread from the liver to the lungs, causing primary or secondary pulmonary echinococcosis, respectively. Pulmonary echinococcosis is a clinically challenging condition in which anthelminthic regiments are important, but surgery has the central role in removing the cysts and preventing recurrences. Surgical treatment may involve cystotomy, enucleation, capitonnage, or atypical resections, which occasionally are in combination with hepatic procedures. The utilization of modern devices is greatly underdescribed in surgery for thoracic infections, even though these facilitate much of the work. Therefore, this article aims to describe pulmonary echinococcosis and the role of modern surgical devices in the treatment process. Furthermore, we report surgical treatment of three different cases of pulmonary echinococcosis. Surgeries of uncomplicated and ruptured hepatic or pulmonary cysts are described. Simple small pulmonary echinococcal lesions can be excised by endostaplers both for diagnostic and curative reasons. Larger cysts can be removed by energy devices unless large bronchial air leaks occur. Complicated cysts require treatment by more extensive techniques. Inexperienced surgeons should not abstain but should carefully decide preoperatively how to proceed.

Proteomics investigation of human sera for determination of postoperative indicators of pulmonary cystic echinococcosis

BACKGROUND

Cystic echinococcosis (CE)/hydatidosis is an important zoonotic parasitic disease caused by the larval stage of Echinococcus granulosus. The disease is a major health problem all over the world. Finding specific and sensitive biomarkers for follow-up of CE in patients after surgery is essential. Using proteomics methods, the present study aimed to evaluate post-surgical treatment by finding probable biomarker/s in the serum of human lungs CE.

METHODS

A total of 24 human sera were tested. These sera included eight confirmed lung/s CE patients sera before surgery (BS), eight sera 12 months post-surgery (12MPS) as well as eight control sera from healthy people. Proteomics methods including 2DE and LC-MS/MS were performed on the specimens followed by bioinformatics analysis. Differentially expressed proteins (DEP) were detected and, separately integrated with protein-protein interaction (PPI) data to construct the PPI network.

RESULTS

A total of 171 protein spots were detected in three groups including BS, 12MPS, and control groups; of which a total of 106 DEP have been expressed based on fold changes > = 2 and p-value < 0.05. More analysis was performed and a total of 10 protein spots were selected for identification by mass spectrometry showing the following proteins: APOA1, BGN, SPP2, EAF1, ACOXL, MRPL55, MCTP2, SEPTIN1, B4GALNT1, and ZNF843. Based on centrality parameters of the PPI network (degree and betweenness) five Hub-bottlenecks proteins with significant centrality values were found including APOA1, BGN, SPP2, EAF1, and ACOXL.

CONCLUSION

This study showed five proteins as hub-bottleneck proteins; of which APOA1 was more prominent. It can be concluded that a change in expression of this protein in patients' sera could be used as an indicator tool for the achievement of lungs CE surgical therapy.

Determining the Frequency of Cystic Echinococcosis among Suspected Cases Referred to Health Centers Southwest Iran, and Post-Treatment Serologic Follow-up

Background:

This study was designed to determine the frequency of hydatidosis in Khuzestan Province, Iran and to evaluate the antibody changes in infected individuals after treatment.

Methods:

Overall, 454 sera were collected from health centers of Khuzestan Province, southern Iran (from 2013 to 2018). Demographic data such as age, gender and history of disease were recorded. Serum samples were investigated for antibody against CE by ELISA using antigen B. Thirty six of cases were followed up after treatment.

Results:

Among the 454 evaluated cases, antibody against CE was detected in 184 (40.52%) including 115 (62.5%) females and 69 (37.5%) males. Age distribution was from 8–97 yr, the highest prevalence of hydatid cyst was observed in age group 40–49 years. Liver was the most infected organ (76.63%). Relapse of CE occurred in 23 of patients. In the majority of patients the antibody decreased, whereas in some cases increased CE antibody observed during post-treatment follow up.

Conclusion:

Current study indicated the high prevalence of hydatidosis and rate of relapse after treatment among suspected patients. Therefore, long periods and regular follow-up of patients after treatment is necessary and for these monitoring, antibody assay can be an appropriate method.

Serodiagnosis of human cystic echinococcosis based on recombinant antigens B8/1 and B8/2 of Echinococcus granulosus

BACKGROUND

Cystic echinococcosis (CE) is a widespread parasitic disease caused by the larval stage of Echinococcus granulosus. Since current methods for the diagnosis of CE are not efficient enough, rapid, and reliable tests are required for the acceleration of CE diagnosis. The present study aimed to produce recombinant B8/1 and B8/2 antigens of E. granulosus and evaluate their sensitivities and specificities separately and simultaneously for the diagnosis of CE.

METHODS

The recombinant B8/1 and B8/2 antigens were produced and used in an ELISA system for the diagnosis of CE. The sera specimens including 30 sera from pathologically confirmed CE patients, 30 from other non-CE patients, and 30 from healthy controls, were evaluated by the ELISA, using AgB8/1 and AgB8/2.

RESULTS

The results showed a sensitivity of 93.33%, 90%, and 96.7% for AgB8/1, AgB8/2, and their combination, respectively. The specificities were 91.7%, 93.33%, and 93.33% for AgB8/1, AgB8/2, and their combination, respectively.

CONCLUSION

Simultaneous usage of AgB8/1 and AgB8/2 increased the test sensitivity for the diagnosis of CE. Furthermore, the specificity of AgB8/1 and AgB8/2 combination was more than AgB8/1 and equal to AgB8/2 alone. The findings revealed that the simultaneous usage of AgB8/1 and AgB8/2 could be a suitable approach for the diagnosis of CE.

Targeted Sequencing of Genomic Repeat Regions Detects Circulating Cell-free Echinococcus DNA

Background

Echinococcosis is a chronic zoonosis caused by tapeworms of the genus Echinococcus. Treatment of the disease is often expensive and complicated, sometimes requiring extensive surgery. Ultrasonographic imaging is currently the main technique for diagnosis, while immunological analysis provides additional information. Confirmation still needs pathological analysis. However, these diagnostic techniques generally detect infection in late stages of the disease. An accurate, early and non-invasive molecular diagnostic method is still unavailable.

Methodology/Principal findings

We sequenced the cell-free DNA (cfDNA) from plasma of echinococcosis patients and confirmed the presence of Echinococcus DNA. To improve detection sensitivity, we developed a method based on targeted next-generation sequencing of repeat regions. Simulation experiments demonstrate that the targeted sequencing is sensitive enough to detect as little as 0.1% of an Echinococcus genome in 1 mL of plasma. Results obtained using patient plasma shows that the Area Under the Curve (AUC) of the method is 0.862, with a detection sensitivity of 62.50% and specificity of 100%, corresponding to a Youden-index of 0.625.

Conclusions/Significance

This study provides evidence that hydatid cysts release cfDNA fragments into patient plasma. Using the repeat region targeted sequencing method, highly specific detection of Echinococcus infection was achieved. This study paves a new avenue for potential non-invasive screening and diagnosis of echinococcosis.

Echinococcosis is a severe chronic parasitic disease caused by tapeworms of the genus Echinococcus. According to the World Health Organization, there are more than 1 million people living with echinococcosis worldwide. For decades, little progress has been made to develop a molecular diagnosis and specific treatment for the disease. Although imaging and immunological detection are used for diagnosis, these technologies are either only effective for late stages of the disease or hardly conclusive. The detection of cell-free DNA has been a powerful tool for precise diagnosis. In this study, we showed the presence of Echinococcus-derived cell-free DNA in plasma of echinococcosis patients. We further established an assay to detect parasite DNA in blood samples based on amplification of Echinococcus specific repeat regions followed by targeted next-generation sequencing. This technique provides a new method for potential extensive screening and precision diagnosis of echinococcosis with high specificity.

The clinical and cytomorphological spectrum of hydatid disease

INTRODUCTION

Hydatid disease (HD) is caused by the tapeworm of the genus Echinococcus. Fine-needle aspiration cytology (FNAC) is an expedient diagnostic technique that may be used for its rapid diagnosis.

AIM

To study the clinical and cytomorphological spectrum of HD diagnosed by cytology.

MATERIAL AND METHODS

A total of 24 patients diagnosed with HD on FNAC and fluid were studied over a period of 5.5 years. May Grunwald Giemsa, Periodic acid Schiff, and Haematoxylin and Eosin stained smears were studied and analysed for the cytomorphological spectrum of HD.

RESULTS

Amongst the 24 patients studied, the mean age was 29.8 years (range 6-64 years). There was equal sex preponderance with 12 males and 12 females. The most common organ involved was lung (54.1% of cases) followed by liver (25% of cases). Presence of laminated membranes (n-20, 83.3%) followed by presence of hooklets (n-13, 54.1%) were the common cytological features. Scolices and protoscolices representing endocyst were seen in 37.5% of cases (n-9).

CONCLUSION

Clinicians and pathologists should be aware of the clinical and morphological spectrum of HD respectively for immediate diagnosis followed by prompt management.

Co-existence of hepatocellular carcinoma and cystic echinococcosis

PURPOSE

Co-existence of hepatocellular carcinoma (HCC) and cystic echinococcus (CE) is extremely rare. Echinococcus granulosus may exhibit a protective effect against cancer. Herein, this study aimed to evaluate the possible effects of echinococcal infection on HCC patients.

METHODS

Three thousand three hundred hepatic CE patients and 815 HCC patients were retrospectively reviewed between January 2010 and December 2018 in Xinjiang, China, and these patients were 1:5 matched according to their sex, age and tumor TMN stage, and only 13 patients coexisted both CE and HCC. Preoperative ultrasonography (US), computed tomography (CT), liver magnetic resonance imaging (MRI) and dot immune-gold filtration assay (DIGFA) were used for preoperative identification and intraoperative specimens from liver resections were pathologically examined for further confirmation. Survival time was analyzed through Cox proportional hazard model analysis.

RESULTS

The co-existing incidence rate of two diseases was 0.39%. For these concurrent cases, HCC was all at the advanced stage and CE lesions were inactive. Median survival time for HCC patients was 6 month (1-17). However, it was 8 month (3-90) for the co-existing cases and was much longer than the median survival time of HCC patients (P<0.05), which was closely associated with tumor size, location, TMN stage and hydatid size, location, classification. Four of the patients underwent surgical intervention and their median survival time was 17 month (3-68).

CONCLUSIONS

Echinococcus granulosus may elicit a protective effect against the development and progression of HCC, while more basic and clinical researches are needed.

Undifferentiated Embryonal Sarcoma of the Liver Presents as a Molecular Mimic of Parasitic Infection

Medical laboratory tests are becoming more reliable with increased specificity and sensitivity, leading to their use as definitive diagnostic tests for many medical conditions. Enzyme-linked immunosorbent assay (ELISA) tests are convenient, sensitive, and standardly used for rapid detection and quantification of antigens or patient antibodies against specific antigens. However, based upon the specificity and sensitivity of an ELISA test, the results may not be definitive for a specific disease but merely suggestive, due to potential cross-reactivity of antigens and antibodies. Here, we present a case of a 15-year-old male who presented with fever, nausea, and right upper quadrant pain. Computed tomography scan showed an 18-cm liver mass with cystic features. Biopsy results confirmed a diagnosis of undifferentiated embryonal sarcoma of the liver; however, the clinical picture was complicated by positive ELISA results for Echinococcus, Entamoeba histolytica, and histoplasmosis. Due to the absence of travel and positive ELISA result for three different infectious agents, we hypothesize that tumor molecular mimicry might have led to false-positive ELISA results in the absence of infection in this case, demonstrating a limitation of ELISA serology. Critical appraisal of all possible evidence to ensure alignment when assigning the final diagnosis is essential for optimal patient outcomes.

Genetic Diversity of Hepatic/Non-Hepatic Cystic Echinococcosis in Baqiyatallah Hospital, Tehran, Iran

BACKGROUND

Cystic echinococcosis (CE) is a worldwide zoonotic helminthic disease caused by the larval stage of Echinococcus granulosus. The infection is particularly important in terms of economic and medico-veterinary aspects in endemic areas including Iran. Considering the possibility of organ-tropism in E. granulosus strains, the present study was aimed to identify the genotypes of E. granulosus in different organs involved in patients, undergone surgery in Baqiyatallah Hospital, Tehran, Iran from 2005-2015.

METHODS

Overall, 29 formalin-fixed paraffin-embedded tissues (FFPT) from patients with histologically confirmed CE including liver (N: 14) lungs (N: 6) abdomen (N: 2), pancreas (N: 2) and each of spleen, gallbladder and, muscles (N: 1) plus unknown organs (N: 2) were used and genetically characterized using polymerase chain reaction, followed by partial sequencing of mitochondrial cytochrome c oxidase gene subunit 1(cox1) and analyzed.

RESULTS

Nineteen out of 29 isolates including liver (N: 6) lungs (N: 4) abdomen (N: 2), pancreas (N: 2) and each of spleen, gallbladder, and muscle (N: 1), unknown organs (N: 2) obtained from paraffin-embedded blocks of human CE created an acceptable sequence in two directions. All 19 isolates regardless of the organ involved were recognized as E. granulosus sensu stricto (G1).

CONCLUSION

The sequence alignments of the isolates displayed two profiles. All sequenced samples showed E. granulosus sensu stricto (G1) with no organ-related genotype.

Comparison of the Utility of Recombinant B8/2 Subunit of the Antigen B, Native Antigen, and a Commercial ELISA Kit in the Diagnosis of Human Cystic Echinococcosis

Background

Cystic echinococcosis (CE) is a helminthic disease caused by the larval form of Echinococcus granulosus. In the present study, the B8/2 subunit of antigen B (AgB) of E. granulosus was expressed in E. coli host and then applied in a diagnostic ELISA set up.

Methods

The DNA sequence of AgB8/2 subunit from E. granulosus was extracted from the GenBank and codon-optimized according to E. coli codon usage. The target sequence was cloned in an expression vector (pGEX-4T-1). The produced antigen was used in an ELISA system, and its performance for the diagnosis of human hydatid cyst was evaluated, using sera from CE and non-CE patients, along with the sera from healthy subjects. Moreover, the diagnostic value of the recombinant protein was compared with native AgB, as well as with a commercial kit.

Results

Antibodies to hydatid cyst were detected in 27 out of 30 patients corresponding to a sensitivity of 90% (95% CI: 73-98%). Cross-reaction with sera of non-CE subjects was seen in two cases resulted in a specificity of 93.5% (95% CI: 82-98%) for the test. A sensitivity of 87% and specificity of 90% were found for the native form of the antigen, while the ELISA commercial kit had a sensitivity of 97% and specificity of 95%.

Conclusion

Our data show that rEgAgB8/2 is an appropriate source of antigen for the serological diagnosis of human hydatid cyst. Co-expression of the rEgAgB/2 along with other subunits of AgB may enhance the performances of these antigens for the serodiagnosis of human CE.

Lateral flow dipstick antigen assay for human cystic echinococcosis

Cystic echinococcosis (CE) is a neglected zoonotic disease with a worldwide distribution and is a major public health problem in some areas. Diagnosis of CE is mainly based on clinical symptoms, imaging and serological testing, however, improvement in serodiagnosis is still needed. This study was aimed at detecting circulating Echinococcus antigen in CE patients using a lateral flow dipstick (LFD) assay. Three types of hydatid antigens i.e. hydatid cyst fluid (HCF), native antigen B (nAgB) and recombinant antigen B (rAgB) were prepared and polyclonal rabbit antiserum was raised against each antigen. Purified IgG fractions were prepared and a portion was conjugated to gold nanoparticles. After a series of optimizations, a final antigen detection LFD assay was developed using a combination of anti-nAgB-IgG and gold-conjugated anti-HCF-IgG. Evaluation of the assay showed that 27 out of 35 (77%) serum samples from CE patients gave positive results. Meanwhile, the test showed a diagnostic specificity of 82% when tested with sera from 38 healthy individuals and 13 patients with other parasitic diseases. In conclusion, the antigen detection LFD assay seemed to be useful for diagnosis of CE and possibly for post-treatment follow-up, and merit further evaluation studies. We foresee that it may improve serodiagnosis of CE when used in tandem with an antibody detection test.

In Vitro Study on Protoscolicidal Effect of Methanolic Extract of Allium hirtifolium on Protoscoleces of Cystic Echinococcosis

BACKGROUND

Cystic echinococcosis/ hydatidosis is one of the most important parasitic zoonoses worldwide. Usually, surgery is used for the treatment of active cysts. Due to the risk of cyst rupture during surgery, a protoscolicidal agent is usually injected into the cyst before surgery to prevent secondary cyst formation in case of cyst rupture. Due to the side effects of chemical protoscolicidal agents attempts have been focused on herbal medicine. In this regard, Allium sativum has already been used; however, the protoscolicidal effect of Allium hirtifolium from Allium family has not been investigated, so far.

OBJECTIVE

The present study was conducted in order to assess the protoscolicidal effect of methanolic extract of Allium hirtifolium in different concentrations, temperature and exposure times. Cetrimide as a positive control and DMSO as a negative control were also used in this study.

METHODS

The viability of protoscoleces was determined by 0.1% eosin staining method.

RESULTS

The protoscolicidal effect of Allium hirtifolium on protoscoleces was as follows: The mean percent and standard deviation (SD) of protoscolicidal activity of 50 mg/ml concentration of Allium hirtifolium extract in room temperature at 10, 20, 30, 40 and 50 minutes of exposure was 5.88±2.39, 8.59±4.54, 11.82±5.81, 12.31±6.16and 16.96±8.42 respectively; while at 37°C it was 9.10±5.01, 11.52±7.36, 18.64±4.36, 27.07±6.57 and 38.15±12.80, respectively.

CONCLUSION

In conclusion, although Allium hirtifolium from Allium family is similar to Allium sativum; the protoscolicidal effect of its methanolic extract is not similar and less than A. sativum extract.

Protoscolicidal Effects of the Garlic Chloroformic Extract on the Protoscolices of Hydatid Cyst at a Short Exposure Time, up to Five Minutes

BACKGROUND

The treatment of choice for hydatidosis as an important zoonotic disease is surgery. Different agents are injected into the cyst to prevent secondary hydatidosis. To avoid the side effects of such protoscolicidal agents, considering the high protoscolicidal effects of the garlic extract, we conducted the present study on protoscolices in limited applicable times and compared the extract with some chemical agents.

METHODS

Sheep's liver and lung cysts were collected. Ninety tubes were selected and divided into 3 sets (for different exposure times), each one comprising 5 groups of 6 tubes. Each tube contained 3000-4000 protoscolices. The groups were 0.5% cetrimide (as positive control), 20% hypertonic sodium chloride, 0.5% silver nitrate, 0.9% normal saline (as negative control), and the garlic chloroformic extract (200 mg/mL). The viability of the protoscolices was assessed using 0.1% eosin. The ANOVA and LSD were used to compare the mean viability of the protoscolices after exposure to the different agents at different times and concentrations. The data were analyzed using SPSS software, version 17. A P<0.05 was considered significant.

RESULTS

Our findings showed that the protoscolicidal effects of the garlic extract at 1 (P<0.001) and 2 (P<0.001 and P=0.003) minutes of exposure were higher than those of sodium chloride and silver nitrate. At 5 minutes of exposure, there was no difference between the garlic extract and sodium chloride (P=0.36); however, the difference between these agents and silver nitrate was significant.

CONCLUSION

The garlic chloroformic extract in a short exposure time had high protoscolicidal effects and could substitute other agents.

Seroepidemiological study of cystic echinococcosis in nomadic communities in the southwest of Iran: A population-based study

The current study aimed at the seroepidemiological survey of human cystic echinococcosis (CE) in nomadic people in Boyer-Ahmad District in the southwest of Iran. One thousand and five nomads were selected by cross-sectional sample collection in nomadic tribes of Boyer-Ahmad District in the southwest of Iran. Blood samples were taken from each individual, and the sera were tested for detection of anti-hydatid cyst antibodies using antigen B-ELISA. A predesigned questionnaire which contained basic epidemiological and individual information related to hydatid cyst was filled for each subject during sample collecting. Subjects of the study were 227 males (22.6%) and 778 (77.4%) females. The mean age of the participants was 40.4 years old (±16.6). Anti-hydatid cyst antibodies were detected in 81 (8.1%) of the subjects. Seroprevalence rate for CE in females (9%) was more than males (4.8%). Multivariate logistic regression revealed significant associations between CE seropositivity and sex (odds ratio [OR] = 1.88; 95% confidence interval [CI] = 0.93-3.80) and dog ownership (OR = 8.3; 95% CI = 3.94-16.37). The rate of infection with CE in nomadic people in southwest of Iran is considerable. Treatment of dogs and increasing the level of people awareness may contribute a substantial advancement in the control of the disease in the area.

Genetic Variability of Antigen B8/1 among Echinococcus granulosus Isolates from Human, Cattle, and Sheep in Fars Province, Southern Iran

BACKGROUND

Cystic echinococcosis (CE), known as hydatid cyst, is a zoonotic parasitic infection caused by the larval stage of Echinococcus granulosus (E. granulosus). Antigen B, the major component of hydatid cyst fluid, is encoded by members of a multigene family. The present study aimed to evaluate the genetic diversity of the gene encoding antigen B8/1 (EgAgB8/1) among the main intermediate hosts of E. granulosus.

METHODS

Twenty-eight hydatid cyst isolates (10 sheep, 9 human, and 9 cattle) were collected in Fars province, Iran. DNA was extracted from each cyst and PCR, followed by DNA sequencing was used to identify potential EgAgB8/1 sequence variation and polymorphism. A phylogenetic tree was constructed using MEGA 7.0 software and the maximum likelihood method.

RESULTS

Using EgAgB8/1 primers, an approximately 315 bp band was amplified from all the isolates. The PCR products were sequenced, and the sequences were deposited in GenBank (accession numbers, KY709266-KY709293). The polymorphism variation among the isolates was 0.0, while intra-species variation within the isolates and related sequences in GenBank was 0.5-1%. Analysis of the phylogenetic tree revealed that the isolates from humans, sheep, and cattle all cluster in one group and are homologous to the EgAgB8/1 M1 allele.

CONCLUSION

Findings of this study revealed close similarity between the EgAgB8/1 of human, sheep, and cattle E. granulosus isolates. However, differences were found between the EgAgB8/1 sequences in our study and those reported from other CE endemic areas. Whether such similarities and differences exist in other subunits AgB subunits require further study.

DNA extraction from hydatid cyst protoscolices: Comparison of five different methods

Aim:

The current study aimed to find out a simple, practical and high throughput DNA isolation method for extraction of DNA from hydatid cyst samples.

Materials and Methods:

Cattle and sheep isolate of hydatid cysts were obtained from the slaughterhouse, and hydatid fluid and protoscolices were collected in a sterile condition. Protoscolices were washed, 3 times with phosphate buffered saline, and DNA was extracted by different methods including manual extraction with freeze/thawing and phenol-chloroform, Triton X-100 extraction, and by a commercial kit (YTA, Yekta Tajhiz Azma, Iran) with three different modifications in the kit’s manufacturer instructions. The obtained DNA from the different methods was evaluated by Nanodrop in terms of the yield of DNA and carbohydrates or protein contaminations. To compare the quality of the extracted DNA, two pieces of the mitochondrial genome of Echinococcus granulosus, cox1, and nad1, were polymerase chain reaction (PCR)-amplified, using each of the DNA prepared by different methods. Electrophoresis of PCR products was carried out on the agarose gel.

Results:

The DNA extracted by manual method, using phenol/chloroform, had the highest yield, yet with the highest level of protein and carbohydrate contamination. The DNA extracted using two-step incubations, initially at 60°C for 2 h and then overnight at 37°C, was the most purified DNA with the lowest rate of contamination.

Conclusion:

Findings of the study demonstrated that modification in the currently available commercially DNA extraction kit resulted in the development of a high throughput DNA isolation method. This method can be recommended for the extraction of DNA from hydatid cysts, especially the cattle isolate where the extraction of DNA in these samples are usually problematic.

Laboratory Diagnosis of Echinococcus spp. in Human Patients and Infected Animals

Among the species composing the genus Echinococcus, four species are of human clinical interest. The most prevalent species are Echinococcus granulosus and Echinococcus multilocularis, followed by Echinococcus vogeli and Echinococcus oligarthrus. The first two species cause cystic echinococcosis (CE) and alveolar echinococcosis (AE) respectively. Both diseases have a complex clinical management, in which laboratory diagnosis could be an adjunctive to the imaging techniques. To date, several approaches have been described for the laboratory diagnosis and followup of CE and AE, including antibody, antigen and cytokine detection. All of these approaches are far from being optimal as adjunctive diagnosis particularly for CE, since they do not reach enough sensitivity and/or specificity. A combination of several methods (e.g., antibody and antigen detection) or of several (recombinant) antigens could improve the performance of the adjunctive laboratory methods, although the complexity of echinococcosis and heterogeneity of clinical cases make necessary a deep understanding of the host-parasite relationships and the parasite phenotype at different developmental stages to reach the best diagnostic tool and to make it accepted in clinical practice. Standardization approaches and a deep understanding of the performance of each of the available antigens in the diagnosis of echinococcosis for the different clinical pictures are also needed. The detection of the parasite in definitive hosts is also reviewed in this chapter. Finally, the different methods for the detection of parasite DNA in different analytes and matrices are also reviewed.

Seroprevalence of cystic echinococcosis in blood donors in Fars province, southern Iran

Cystic echinococcosis (CE) is one of the most important zoonotic diseases in different geographical areas of the world including Iran. The current study aimed to assess the seroprevalence of human cystic echinococcosis (CE) in healthy blood donors in Fars province, southern Iran. A total of 1068 serum samples were collected from blood donors from five blood service centers of Fars province in south of Iran. Antigen B was prepared from sheep hydatid cyst fluid and collected sera were evaluated for anti-hydatid cyst antibodies, using antigen-B ELISA. Demographic features of the participants were also recorded during the sample collection. Anti hydatid cyst antibodies were detected in sera of 60 out of 1068 blood donors corresponding to overall seroprevalence of 5.6% in this population. Rate of seroprevalence was 6.7% in females and 5.5% in males. The highest rate of infection (8.3%) was found in age group of higher than 50 years old. There were no significant differences between seropositivity to CE and sex, age or place of residence of the participants (P > 0.05). Findings of this study showed that the rate of CE infection in Fars province, southern Iran, is relatively high. Some of these seropositive cases may have active hydatid cyst in their tissues without overt sign or symptoms.

Hepatic Echinococcal Cysts: A Review

Cystic echinococcosis (CE) is a widely endemic helminthic disease caused by infection with metacestodes (larval stage) of the Echinococcus granulosus tapeworm. E. granulosus are common parasites in certain parts of the world, and are present on every continent with the exception of Antarctica. As a result, a large number of people are affected by CE. The increased emigration of populations from endemic areas where prevalence rates are as high as 5-10% and the relatively quiescent clinical course of CE pose challenges for accurate and timely diagnoses. Upon infection with CE, cyst formation mainly occurs in the liver (70%). Diagnosis involves serum serologic testing for antibodies against hydatid antigens, but preferably with imaging by ultrasound or CT/MRI. Treatment methods include chemotherapy with benzimidazole carbamates and/or surgical approaches, including percutaneous aspiration injection and reaspiration. The success of these methods is influenced by the stage and location of hepatic cysts. However, CE can be clinically silent, and has a high risk for recurrence. It is important to consider the echinococcal parasite in the differential diagnosis of liver cystic lesions, especially in patients of foreign origin, and to perform appropriate long-term follow-ups. The aim of this review is to highlight the epidemiology, natural history, diagnostic methods, and treatment of liver disease caused by E. granulosus.

Clinical and Molecular Evaluation of a Case of Giant Primary Splenic Hydatid Cyst: A Case Report

Spleen is an unusual location for hydatid cyst. Here we report a case of primary splenic hydatid cyst in a 41-yr-old Iranian woman from Yasuj, southwest of Iran. The patient had been admitted to Shahid Beheshti Hospital because of abdominal pain. Abdominal sonography revealed a hypoechoic lesion of 150 X 130 mm in the spleen, suggestive of hydatid cyst. Splenectomy was performed for the patient and surgical interventions revealed a hydatid cyst occupying most of splenic parenchyma. She was discharged on the 5 day of her operation. Postoperative diagnosis and confirmation of hydatid cyst was done by histopathological, molecular and serological approaches. Histopathological evaluation revealed the classical laminated layer of hydatid cyst. DNA was extracted from a part of cyst and PCR amplified. Sequencing and analysis of PCR product revealed that the isolate has the most similarity with G1 strain of Echinococcus granulosus. Patient's serum was positive for IgG anti-hydatid cyst antibodies, using antigen-B ELISA.

Immunodiagnosis of human hydatid disease: Where do we stand?

Cystic echinococcosis (CE) is a zoonotic parasitic infection caused by the larval stage of Echinococcus granulosus. Diagnosis of CE mainly relies on a combination of serological testing along with imaging approaches. A variety of serological methods, mainly based on hydatid cyst fluid, antigen B (AgB) and antigen 5, have been developed and used for immunodiagnosis of CE, yet their performances are not satisfactory. Although utilizing of recombinant or synthetic antigens, improved the performance of serological tests, it has not applicably overcome the problem of low sensitivity and cross reactivity, seen in the diagnosis of CE. Performances of immunodiagnostic tests based on AgB subunits are promising. The 8 kDa subunit of AgB is the most studied antigen in native, synthetic or recombinant form for diagnosis of CE. From the 5 subunits of AgB, antigen B8/1 and B8/2 provided the highest diagnostic sensitivity and specificity. Moreover, detecting of specific antibodies of IgG subclasses has improved the efficacy of immunodiagnostic tests. Among the IgG subclasses, both IgG2 and IgG4 are considered as good markers for diagnosis and IgG4 as a suitable marker for follow up of the patients. In this review an overview of immunodiagnostic methods, related antigens and their performances in the diagnosis of CE are given. The paper highlights pitfall and challenges in the serological diagnosis of CE. Moreover, limitation of currently available immunodiagnostic tests and the most recent development in the designing and application of serological assays for diagnosis of CE in human are addressed.

A Bystander Effect of Lung Cancer Chemotherapy on Chronic Echinococcal Disease

Hydatid cystic disease is a parasitic infestation caused by Echinococcus granulosus and commonly manifests as hepatic and pulmonary cysts. When feasible, based on cyst size and location, surgical resection is potentially curative. Post-surgical recurrence of disease is encountered in up to 25% of patients. Secondary peritoneal contamination is a recognized complication in 5-10% of cases. Disseminated disease is usually palliated using systemic anti-parasitic agents such as benzimidazoles, albendazole and mebendazole but worsening of disease post-systemic treatment is frequent in 14-25% of patients. In this report, we share our experience of a patient with long-standing, chronic disseminated hydatidosis and subsequent diagnosis of non-small cell lung cancer who manifested evidence of reduced activity of the echinococcal disease following institution of chemotherapy for his new diagnosis of lung cancer. There was significant reduction in the serum level of anti-echinococcal antibody titers in tandem with chemotherapy administration. There was also minimal but notable decrease in the size of the cysts on serial cross-sectional imaging obtained for monitoring cancer response to chemotherapy. This intriguing observation of a possible benefit of anticancer chemotherapy against echinococcal disease in this index case may provide new insights for therapeutic exploration in disseminated echinococcal disease.

Lateral flow test using Echinococcus granulosus native antigen B and comparison of IgG and IgG4 dipsticks for detection of human cystic echinococcosis

Cystic echinococcosis (CE) caused by infection with Echinococcus granulosus is of major concern for humans in many parts of the world. Antigen B was prepared from E. granulosus hydatid fluid, and Western blots confirmed eight batches showing a band corresponding to the 8-/12-kDa subunit with positive serum and no low-molecular mass band (< 15 kDa) with negative serum. The batches were pooled and used to prepare lateral flow immunoglobulin G4 (IgG4) and IgG dipsticks. Diagnostic sensitivity was determined using serum samples from 21 hydatidosis patients, and diagnostic specificity was established using sera from 17 individuals infected with other parasites and 15 healthy people. IgG4 dipstick had a diagnostic sensitivity of 95% (20 of 21) and a specificity of 100% (32 of 32). The IgG dipstick had a sensitivity of 100% (21 of 21) and a specificity of 87.5% (28 of 32). Thus, both IgG and IgG4 dipsticks had high sensitivities, but IgG4 had greater specificity for the diagnosis of human CE.

Evaluation of purified 27.5 kDa protoscolex antigen-based ELISA for the detection of circulating antigens and antibodies in sheep and human hydatidosis

Hydatidosis is a zoonotic disease caused by the larval stage of Echinococcus granulosus, and the diagnosis of hydatidosis to date remains unresolved despite the development of many serological techniques. The present study aimed to develop an antigen-based enzyme-linked immunosorbent assay (ELISA) using IgG anti-27.5 kDa protoscolex antigen (27.5 PA) for measuring circulating protoscolex antigen (CPA), for comparison with an antibody detection assay, in sera of naturally infected sheep and humans in highly endemic areas in Egypt. In sheep, the sensitivity of ELISA in detecting anti-27.5 PA IgG and CPA was 75.0 and 60.0%, respectively, and the recorded specificity was 80.0 and 88.0%, respectively. In humans, the sensitivity of ELISA in detecting anti-27.5 PA IgG and CPA was 62.5 and 52.5%, respectively, while the specificity of the assay was 66.7 and 75.0%, respectively. In conclusion, an antibody detection assay is still superior and is more sensitive than an antigen detection assay, especially in diagnosing an active infection in which hydatid cysts are predominant. An antigen detection assay may be a useful approach to assessment of the efficacy of treatment, especially after removal of the cyst. Further studies are recommended to improve the diagnostic efficacy of an antigen-based ELISA method by using a highly purified recombinant antigen.

Serodiagnosis of human hydatidosis with an ELISA developed based on antigens derived from sheep hydatid cysts and comparison with a commercial human ELISA kit

OBJECTIVE

To explore the serodiagnosis of hydatid cyst in human using different antigens of sheep (hydatid fluid, Somatic and Excretory/secretory antigens of protoscolex) by ELISA and compares this result with commercial human ELISA kit.

METHODS

One hundred blood samples from patients with history of severe abdominal pain and eosinophilia were obtained. Ten serum samples were obtained from surgically and pathologically confirmed cystic echinococcosis patients from Mashhad university hospital as positive control and 5 serum samples from infant under one year old as negative control. Blood samples were centrifuged at 3 000μg at 20 °C for 15 min and sera were stored at -20 °C. First, these samples were tested for the presence of antibody by commercial human ELISA. Then, ELISA was developed on microplates coated with hydatid fluid, Somatic and Excretory/secretory antigens of protoscolex of sheep.

RESULTS

The results of this study as analyzed by Kappa test showed that, hydatid fluid antigen could be used as a precise source of detection in indirect ELISA test.

CONCLUSIONS

Hydatid fluid in comparison with Excretory-secretory and somatic antigens showed more compatibility agreement in kappa test which can be used for further studies in development of any ELISA test for diagnosis of human hydatidosis.

Using specific synthetic peptide (p176) derived AgB 8/1-kDa accompanied by modified patient's sera: a novel hypothesis to follow-up of Cystic echinococcosis after surgery

Cystic echinococcosis (CE) is caused by the larval stage of the tapeworm Echinococcus granulosus. Until now, CE does not have an effective follow-up after surgery. To date, CE follow-up is conducted based on either antibody or antigen detection assays by double antibody sandwich ELISA. Unlike antigen detection, antibodies to imply exposure to an Echinococcus infection while their titration could remain for a longer period (1-10years) after surgery. Likewise, antibody respond may be related to the location of a mature hydatid cyst. Antigen detection shows presence of CE infection, it is extremely important and necessary in follow-up of CE after surgery. The circulating antigen (CAg) titration decrease faster than circulating antibody (during 1-3weeks) after operation. Location of hydatid cyst in detecting antigen is affected less than antibody also. Regarding this subject, antigen detection has several limitations that lead to be used less in CE follow-up. Although, AgB 8/1-kDa subunit is considered as a principle and immunogenic CAg but sensitivity of CAg detection compared to with antibody has variable range, between 33% and 85% which owing to formation of circulating immune complexes (CICs) in result of antigen - antibody complex. The another problem is non using specific CAg (AgB 8/1-kDa subunit) for production of specific paratopes (rabbit hyper immune antiserum) against AgB 8/1-kDa which is used as capture (primary) antibody in double antibody sandwich ELISA assay. The designation of synthetic peptides from conserved regions of AgB 8/1-kDa can help to this problem. These regions (motifs) should be selected for allelic, dominant, immunogenic and conserved without any genetic variation. The first part of this hypothesis suggests which patient's sera should be treated with acidic buffers such as boric acid, acetic acid, glycine/HCl, polyethylene glycol (PEG) or combination of each of them accompanied by boiling patient's sera which causes breaking Ag-Ab complexes and in result of releasing AgB 8/1. These modifications are effective to releasing CAg from CIC. To date, the synthetic peptides have been widely used in CE serodiagnosis based on circulating antibody detection only. In second part of this hypothesis suggests the using synthetic peptide of p176 derived AgB 8/1-kDa subunit containing conserved specific epitopes for preparation of specific paratopes (rabbit hyper immune antiserum) based on CAg detection. So, there is no need any native antigens for preparation of non-specific rabbit hyper immune antiserum. These novel improvements can help to decrease the cross-reactivity with other parasitic diseases (specificity). Increasing antigen detection could make a chance in sensitivity of patient's sera and in result of the best and suitable tool for CE follow-up.

Extrahepatic primary adrenal alveolar echinococcosis: a review

BACKGROUND

Primary echinococcosis, and especially primary alveolar echinococcosis (AE) is rare among adrenal lesions.

METHODS

We report a case of primary AE in a 28-year-old male with low backache and occasional upper limb pain lasting for six months, and review the pertinent but sparse literature on this disorder.

RESULTS

Evaluation of the patient revealed an abdominal mass as right adrenal AE. The adrenal gland is a rare extrahepatic site of occurrence of echinococcosis, and particularly of AE. Patients with adrenal echinococcosis usually have nonspecific clinical symptoms. Imaging examinations revealed clearly the features of AE and its surrounding pathology. Alveolar echinococcosis was seen as an inhomogeneous pseudotumor with irregular boundaries, an irregular central pseudocystic appearance, and infiltration into surrounding structures. On contrast-enhanced computed tomography, the periphery of the mass in AE may be enhanced and multicentric vesicles may be seen. Magnetic resonance imaging may show the multivesicular morphology of lesions. The definitive diagnosis of AE should be confirmed by pathologic or serologic examination. Radical surgical resection of the removable parasitic lesion, followed by anti-infective therapy with benzimidazoles, is the primary method for treating AE.

CONCLUSION

Although primary adrenal AE is rare, it should be included in the differential diagnosis of adrenal masses, especially in regions where AE is endemic.

Disseminated lung hydatidosis from intraabdominal hydatid cyst via inferior vena cava (IVC): a very rare presentation

Hydatid disease is a parasitic infestation by Echinococcus granulosus characterized by cyst formation in various organs. Secondary involvement due to hematogenous dissemination may be found in almost any anatomic location. We herein reported a very rare case of lung hydatidosis as a result of disseminated hydatid cysts from intraabdominal through IVC in a young female patient. She was treated with surgical intervention in two stages followed by Albendazole therapy.

A review on diagnostic and preventive aspects of cystic echinococcosis and human cysticercosis

Cystic echinococcosis and human cysticercosis have recently been included in the list of "neglected tropical diseases" by the World Health Organization (WHO). Both are zoonoses which are prevalent throughout the world and lead to considerable mortality, morbidity, and economic losses as well. This review deals with the disease burden of these two neglected cestode infections. Diagnostic modalities with their specific advantages and disadvantages have also been discussed. Recent developments in immunodiagnostic assays for the two diseases have been dealt with. Various control strategies including the use of veterinary vaccines have been highlighted.

Evaluation of rabbit antibody response against 8 and 16 kDa recombinant subunits of antigen B from Echinococcus granulosus

OBJECTIVE

To immunize rabbits with 12 and 16 kDa recombinant subunits of antigen B from Echinococcus granulosus (E. granulosus) and measuring polyclonal antibody and humoral immune response using ELISA and gel diffusion.

METHODS

Two mentioned antigens were cloned and expressed in expression vector and purified by affinity chromatography. Four young rabbits were selected and challenged intradermally with yielded recombinant antigens. Rabbits' sera were collected post infection and were tested using ELISA and gel diffusion for polyclonal antibody detection 10 days after last injection.

RESULTS

The specific antibody against the recombinant peptides was efficiently produced within 4 weeks post infection.

CONCLUSIONS

Produced recombinants proteins could induce the immune response of the rabbits successfully. This process might improve the clarification of diagnosis and vaccination as regards hydatidosis.

Performance of antigen B isolated from different hosts and cyst locations in diagnosis of cystic echinococcosis

BACKGROUND

The aim of this study was to assess the performance of Antigen B (AgB) isolated from different Echinococcusgranulosus intermediate hosts and from different cyst locations for immunodiagnosis of human cystic echinococcosis (CE).

METHODS

Hydatid cyst fluids were collected from lung and liver cysts of sheep, liver cysts of goats, lung cysts of camels and cattle, and liver cysts of human. AgB was purified from each of these hydatid cysts fluids. Serum samples obtained from 47 pathologically confirmed cases of CE along with 30 sera samples from non-CE patients and 40 sera from healthy individuals were tested by ELISA using AgB prepared from different hosts or cyst locations.

RESULTS

The highest sensitivity (97.8%) for diagnosis of CE was seen with AgB prepared from human liver cysts. This maximal sensitivity was followed by AgB isolated from those of sheep liver and lung cysts. The least sensitivity was found with AgB prepared from bovine lung cysts. The highest specificities (97.1%) were observed with AgB isolated from human liver cysts followed by those of sheep and goat liver cysts while the lowest specificity was seen with AgB isolated from bovine lung cysts. In view of the specificities and sensitivities of the different AgB, the best validity was found for AgB prepared from human liver cysts while the least validity was found with AgB prepared from bovine lung cysts.

CONCLUSION

For any AgB-based tests, obtaining of the antigen from one of these sources will significantly increase the diagnostic sensitivity and specificity of the assay.