World Health Organization Estimates of the Global and Regional Disease Burden of 11 Foodborne Parasitic Diseases, 2010: A Data Synthesis

BACKGROUND

Foodborne diseases are globally important, resulting in considerable morbidity and mortality. Parasitic diseases often result in high burdens of disease in low and middle income countries and are frequently transmitted to humans via contaminated food. This study presents the first estimates of the global and regional human disease burden of 10 helminth diseases and toxoplasmosis that may be attributed to contaminated food.

METHODS AND FINDINGS

Data were abstracted from 16 systematic reviews or similar studies published between 2010 and 2015; from 5 disease data bases accessed in 2015; and from 79 reports, 73 of which have been published since 2000, 4 published between 1995 and 2000 and 2 published in 1986 and 1981. These included reports from national surveillance systems, journal articles, and national estimates of foodborne diseases. These data were used to estimate the number of infections, sequelae, deaths, and Disability Adjusted Life Years (DALYs), by age and region for 2010. These parasitic diseases, resulted in 48.4 million cases (95% Uncertainty intervals [UI] of 43.4-79.0 million) and 59,724 (95% UI 48,017-83,616) deaths annually resulting in 8.78 million (95% UI 7.62-12.51 million) DALYs. We estimated that 48% (95% UI 38%-56%) of cases of these parasitic diseases were foodborne, resulting in 76% (95% UI 65%-81%) of the DALYs attributable to these diseases. Overall, foodborne parasitic disease, excluding enteric protozoa, caused an estimated 23.2 million (95% UI 18.2-38.1 million) cases and 45,927 (95% UI 34,763-59,933) deaths annually resulting in an estimated 6.64 million (95% UI 5.61-8.41 million) DALYs. Foodborne Ascaris infection (12.3 million cases, 95% UI 8.29-22.0 million) and foodborne toxoplasmosis (10.3 million cases, 95% UI 7.40-14.9 million) were the most common foodborne parasitic diseases. Human cysticercosis with 2.78 million DALYs (95% UI 2.14-3.61 million), foodborne trematodosis with 2.02 million DALYs (95% UI 1.65-2.48 million) and foodborne toxoplasmosis with 825,000 DALYs (95% UI 561,000-1.26 million) resulted in the highest burdens in terms of DALYs, mainly due to years lived with disability. Foodborne enteric protozoa, reported elsewhere, resulted in an additional 67.2 million illnesses or 492,000 DALYs. Major limitations of our study include often substantial data gaps that had to be filled by imputation and suffer from the uncertainties that surround such models. Due to resource limitations it was also not possible to consider all potentially foodborne parasites (for example Trypanosoma cruzi).

CONCLUSIONS

Parasites are frequently transmitted to humans through contaminated food. These estimates represent an important step forward in understanding the impact of foodborne diseases globally and regionally. The disease burden due to most foodborne parasites is highly focal and results in significant morbidity and mortality among vulnerable populations.

Genotyping of Hydatid Cyst Isolated from Human and Domestic Animals in Ilam Province, Western Iran Using PCR-RFLP

BACKGROUND

Hydatidosis or cystic hydatid disease is one of the most important diseases in human and animals. Identification of strains is important for improvement of control and prevention of disease. The aim of this study was to determine the strains isolated from human and domestic animals in Ilam Province, Iran, using PCR-RFLP method.

METHODS

Respectively, 30 and 4 animal and human hydatid cysts were collected from different slaughterhouses and hospitals of the province. Protoscolices were separated and their DNA genome was extracted by extraction kit. rDNA-ITS1 of each isolated samples was duplicated by BD1(Forward) and 4s (Reverse) Primers. PCR products were studied by electrophoresis and then were digested using TaqI, HpaII, RsaI and AluI restriction enzymes. RFLP products were studied using electrophoresis on 1% agar gel.

RESULT

A fragment of 1000bp was produced from amplification of rDNA-ITS1 of protoscolices using PCR method. After digestion of PCR product by AluI enzyme, 200bp and 800bp, by RsaI, 655bp and 345bp and by HpaII 700bp and 300bp sizes were obtained. TaqI enzyme had no change in fragment size and it remained 1000bp. Considering the method, Ilam strains was specified as E. granulosus sensu stricto (G1-G3).

CONCLUSIONS

Although sheep strain (G1) is dominated in human and different animal in Iran and the world, but more efforts should be done to clarify the true genotype of Ilam strains specified as E. granulosus sensu stricto (G1-G3).

Assessing the effect of highly cited papers on the impact factor of journals in the field of public health

BACKGROUND

The aim of this study was to appraisal the effect of highly cited papers in the field of public health and find out whether the unusual citations affect the ranking order of the journals in this field or not. A total number of 142 journals titles were listed in Journal Citation Report (ISI Thomson) in the field of "Public, Environmental & Occupational Health". All but one of them had published papers at least for a year from 2009 to 2010. Journal title, number of citations and publication year of 45685 papers were collected from ISI web of knowledge database at December 25, 2011. About half of the papers (23226) had no citations and 89.4% (40835) had less than 6 citations. We concluded that the ranking of journals in the field of public health is not affected by the individual papers with unusual number of citations.

Seroprevalence of human hydatidosis using ELISA method in qom province, central iran

BACKGROUND

The objective of this study was to determine the prevalence of cystic echinococcosis (CE) in Qom Province, central Iran using ELISA test.

METHODS

Overall, 1564 serum samples (800 males and 764 females) were collected from selected subjects by randomized cluster sampling in 2011-2012. Sera were analyzed by ELISA test using AgB. Before sampling, a questionnaire was filled out for each case. Data were analyzed using Chi-square test and multivariate logistic regression for risk factors analysis.

RESULTS

Seropositivity was 1.6% (25 cases). Males (2.2%) showed significantly more positivity than females (0.9%) (P= 0.03). There was no significant association between CE seropositivity and age group, occupation, and region. Age group of 30-60 years encompassed the highest rate of positivity. The seropositivity of CE was 2.1% and 1.2% for urban and rural cases respectively. Binary logistic regression showed that males were 2.5 times at higher risk for infection than females.

CONCLUSION

Although seroprevalence of CE is relatively low in Qom Province, yet due to the importance of the disease, all preventive measures should be taken into consideration.

Heavy Worm Burden of Moniliformis moniliformis in Urban Rats with Histopathological Description

BACKGROUND

Due to scarcity of human reports, we took advantage of the heaviest infection of M. moniliformis in rats, to describe histopathological and microanatomical valuable useful keys while confronting human occurrences.

METHODS

Samples were obtained from captured rats in Tehran, capital of Iran, during two decades. Tissue sections were performed through hematoxylin and eosin staining to describe histopathological changes in rat's intestines.

RESULTS

Totally, nine rats were found infected with M. moniliformis amongst 272 obtained rats. Heavy infection has been distinguished in 2 individuals with parasite burden of 141and 73 adult worms. Cross sections of worms within the lumen show mucosal thickness, infiltration of eosinophilic leukocyte and increase in goblet cells.

CONCLUSION

Beyond the uncommonness of human infection with M. moniliformis unitended infections should not be ignored. Abundance of rats and roaches as definite and intermediate hosts must be considered particularly in countries with poor hygiene.

Molecular Identification and Differentiation of Fasciola Isolates Using PCR- RFLP Method Based on Internal Transcribed Spacer (ITS1, 5.8S rDNA, ITS2)

BACKGROUND

In this study, we used both ITS1 and ITS2 for molecular identification of Fasciola species.

METHODS

The region between 18S and 28S of ribosomal DNA was used in PCR-RFLP method for molecular identification of Fasciola species. Ninety trematodes of Fasciola were collected during abattoir inspection from livers of naturally infected sheep and cattle from Khorasan, East Azerbaijan, and Fars provinces in Iran. After DNA extraction, PCR was performed to amplify region ITS1, 5.8S rDNA, ITS2. To select a suitable restriction enzyme, we sequenced and analyzed the PCR products of F. hepatica and F. gigantica samples from sheep and cattle. Tsp509I fast digest restriction enzyme was selected for RFLP method that caused the separation specifically of Fasciola species.

RESULTS

The fragment approximately 1000bp in all of the Fasciola samples was amplified and then digested with the Tsp509I restriction endonuclease. Seventy F. hepatica and 20 F. gigantica were identified of total 90 Fasciola isolates.

CONCLUSION

The new PCR-RFLP assay using Tsp509I restriction enzyme provides a simple, practical, fast, low cost, and reliable method for identification and differentiation of Fasciola isolates.

Seroepidemiological study of human hydatidosis in meshkinshahr district, ardabil province, iran

BACKGROUND

The aim of this study was to conduct a sero-epidemiological survey in Meshkinshahr, Ardabil Province, northwestern Iran to detect the rate of hydatidosis in the city and nearby villages. Literature shows that no such study has been conducted so far.

METHODS

Overall, 670 serum samples were collected from 194 males and 476 females from patients referred to different health centers of the region. All patients filled out a questionnaire and an informed consent. Sera were analyzed using indirect-ELISA test. Ten µg /ml antigens (Antigen B derived from hydatid cyst fluid), serum dilutions of 1:500 and conjugate anti-human coombs with 1:10000 dilutions were utilized to perform the test. Data analysis was conducted using SPSS software ver. 11.5.

RESULTS

The seroprevalence of human hydatidosis was 1.79% by ELISA test in the region. This rate for females was 1.68% and males 2.6%, respectively. There was no significant difference as regards all factors studied and the seropositivity. According to job, farmers and ranchmen had the highest rate of infection as 3.17%. The sero-prevalence of infection was 2.6%% in illiterate people which showed the highest rate. As regards residency, urban life showed no significant difference with rural life (1.1% vs. 2.58%). Age group of 69-90 yr old, with 4.62% as prevalence had the highest rate of positivity.

CONCLUSION

Obtained sero-prevalence of hydatidosis shows more or less a resemblance to other cities of Iran, although due to the specific condition of the city we expected more rate of sero-positivity.

Establishment of Hymenolepis diminuta Life Cycle to Provide Parasite Mass Production

BACKGROUND

The main object of this experimental work was to practise laboratory production both adult and the larval stage of Hymenolepis diminuta with conventional modification to make further studies easier. MATERIALS #ENTITYSTARTX00026;

METHOD

Adults H. diminuta were collected from urban rats in Tehran, Iran. The beetles became infected using blended gravid segments with flour as bait. Cysticercoids have been saved after precise dissection of invertebrate hosts. The exposure of infected beetles to laboratory rats was performed to establish the life cycle.

RESULT

Out of 57 collected rats, three rats were infected with H. diminuta. Almost all exposed beetles found infected with the larval stage of parasite. About one-month later H. diminuta eggs were seen in stool examination of laboratory rats.

CONCLUSION

Rare human occurrence of H. diminuta along with light level of clinical manifestation of this parasite, underestimate the concerns toward its public health importance. Nowadays, various field of studies, such as biochemistry with special focuses on the capability of H. diminuta tegument absorption have performed apart from parasitological views alone. In the present study, establishment of this parasite life cycle has practically provided the access of adult and cysticercoid stages of the tapeworm in further researches.

Molecular Diagnosis of Strongyloides stercoralis Infection by PCR Detection of Specific DNA in Human Stool Samples

BACKGROUND

Strongyloidiasis is mostly an asymptomatic infection and diagnosis of latent infections is difficult due to limitations of current parasitological and serological methods. This study was conducted to set up a PCR-based method for molecular diagnosis of Strongyloides stercoralis infection by detection of copro-DNA in stool samples.

METHODS

A total of 782 fresh stool samples were collected and examined by agar plate culture. Among those sixteen stool samples, which confirmed to be infected with S. stercoralis were examined as positive control to set up each single and nested PCR, using two primer sets designing to amplify partial ribosomal DNA of S. stercoralis genome. Since, single PCR method yielded higher efficacy in detecting positive samples, in the second step, 30 stool samples, which found negative for S. stercoralis by agar plate culture of single stool sample, were examined by single PCR. Data analysis was performed using McNemar's χ(2) test, with consideration of a P-value of <0.05 as indication of significant difference.

RESULTS

In amplification of DNA extracted from stool samples, single PCR detected S. stercoralis DNA target in all 16 positive samples, while nested PCR amplified DNA in only 75% of samples. In the second step, single PCR amplified S. stercoralis extracted DNA in 5 out of 30 samples which were negative by coproculture.

CONCLUSION

Single PCR method amplifying a short (100bp) target represented more efficacies for detection of S. stercoralis in faecal examination compared to agar plate culture and nested PCR, which amplified longer target.

The prevalence of honorary and ghost authorships in Iranian bio-medical journals and its associated factors

BACKGROUND

The purpose of this study was to detect the prevalence of ghost and honorary authors and its determinant factors in bio-medical journals of Iran.

METHODS

The study was done in 2009-10 in Tehran, Kerman, and Iran Medical Universities, Iran. We contacted the first or corresponding authors of the papers had published papers in the recent two issues of Iranian Journal of Public Health, Journal of Kerman University of Medical Sciences, and Tehran University Medical Journal. They explored the role of each coauthor and others who had done mouthing for the paper. Then, according to ICMJE criteria, we counted how many of them are real, honorary or ghost author. For the analysis, we utilized two databases. One included articles as the records and the other included authors as the records.

RESULTS

From 124 articles, with 536 authors, 301 (56.1%) were honorary authors. Each article had 4.35 authors on average, while 2.4 of them were honorary authors. The percentage of honorary author in basic science articles was about 6% more than the articles of clinical sciences. Moreover, 89% of articles had at least one honorary author. About 20% of all articles had more than three honorary authors. Besides, 25 (21.43%) authors confessed they had colleague(s) omitted from the authors list, while only one (0.81%) of them met the authorship criteria. The percentage of agreement between the corresponding and the remaining authors on the number of honorary of the authors was about 47.4% (Kappa= 0.27, P= 0.01).

CONCLUSION

It seems that the present data might assist the authorities to make a decisive decision on amending the process of authorship in Iran.

Gene cloning, expression and serological evaluation of the 12-kDa antigen-B subunit from Echinococcus granulosus

A 12-kDa subunit of antigen B from Echinococcus granulosus has recently been cloned, expressed and used in diagnostic ELISA to test human sera for evidence of cystic echinococcosis. The performance of the ELISA based on the recombinant antigen (rAgB) was compared with that of similar assays based on native antigen B (nAgB) or hydatid-cyst fluid. For the preparation of the rAgB, total RNA was extracted from Ec. granulosus protoscoleces so that antigen-B complementary DNA could be synthesised, amplified by PCR, and then cloned into the pQE30 expression vector. The recombinant plasmid was transformed in Escherichia coli and induced using isopropyl-beta-D-thiogalactopyrano-side. Bacterial samples were collected, lysed and then analysed by SDS-PAGE and western blotting. The recombinant protein was purified by affinity chromatography. Although the performance of the ELISA based on cyst fluid appeared identical to that of the assay based on the recombinant antigen (with a sensitivity, specificity, positive predictive value and negative predictive value of 96.0%, 97.0%, 97.2% and 95.5%, respectively), the corresponding results for the ELISA based on nAgB (98.6%, 100%, 100% and 98.5%) were slightly better. Despite this difference (which was not statistically significant), the comparative ease with which large quantities of the recombinant antigen could be produced make the antigen a potentially useful tool in the diagnosis of cystic echinococcosis.

Neglected human fascioliasis case in a visceral leishmaniasis endemic area, north-Western iran

Ardabil Province, northwestern Iran, is endemic for visceral leishmaniasis of Mediterranean type from many years ago. This situation might cause to underestimate other important diseases, which occur sporadically within the same area. In this case, a 6-year-old male patient in this area was treated as infected with visceral leishmaniasis initially with seropositive result for visceral leishmaniasis. Afterwards, histopathological study of crashed material and tissue sections surprisingly revealed numerous liver fasciolid fluke eggs. This case demonstrates that in an area endemic for a given parasitoses, other important infectious diseases must be considered as well.

Ocular dirofilariasis, a case report

Accidental infection with animal filarial worms in humans is a dilemma for clinicians and parasitologists throughout the world. To date a variety of such rare parasitoses have been reported mostly in tropics and subtropics. Human dirofilariasis is among those unusual zoonotic infections that occasionally have been observed in the eye and in subcutaneous areas exhibiting with nodule formation. Filarial worms are transmitted to humans through invertebrate biological vectors such as certain species of mosquitoes. The present report describes a peculiar case of ocular dirofilariasis in a 49-year-old man resident in Iran.

Serological Evaluation of EgAgB16 kDa, a Recombinant Antigen from Echinococcus granulosus for Diagnosis of Human Hydatidosis

BACKGROUND

Regarding that accurate diagnosis of human hydatidosis still needs more investigations, the present study was conducted to clone, express, and evaluate the gene encoding AgB subunits (EgAgB16 kDa) from Echinococcus granulosus (Iranian G1 strain) and its evaluation by ELISA test.

METHODS

DNA was extracted from protoscoleces and was utilized by PCR for strain identification. Total RNA was prepared with RNeasy protect mini kit from E. granulosus (Iranian G1 strain) protoscoleces collected from naturally infected sheep with hydatid cyst. Recombinant AgB16 kDa was produced using pETDuet as vector and evaluated by ELISA method. A panel of sera including hydatid cyst-infected individuals (n=72), healthy individual (n=48), toxoplasmosis (n=4), strongyloidosis (n=4), kala-azar (n=5) and tuberculosis (n=5) were examined using this recombinant antigen.

RESULTS

Recombinant protein was purified by affinity chromatography using His-Tag column. After purification, recombinant protein was confirmed by western blot analysis using His Tag monoclonal antibody or hydatid positive human serum. The sensitivity, specificity; positive and negative predictive values were calculated as 93.5%, 95.6%, 96% and 92.9%, in that order. The cut-off point was detected 0.3 for rAgB16.

CONCLUSION

While the produced recombinant AgB16 kDa showed promising results in diagnosing human hydatidosis, but more investigations should be implemented to reach an accurate gold standard.

Evaluation of the stability of coated plates with antigen at different temperatures and times by ELISA test to diagnose fasciolosis

BACKGROUND

Considering that ELISA method presently is the test of choice for diagnosis of fasciolosis, the present study was undertaken to evaluate the maximum validity of coated plates at different temperatures and different times during one year of evaluation.

METHODS

Serum samples of patients infected with fasciolosis (n=10), hydatidosis (n=5), toxocariasis (n=5), and negative control sera (n=5) were examined. Two series of plates were considered. The first series were coated with Fasciola homogenate Ag 12 ug/ml, and after some steps were blocked with gelatin and preserved at different temperatures as -80°C, -20°C, -4°C and +4°C. The 2(nd) series were treated under the same criteria but were not blocked with gelatin. Each series were examined by ELISA test from 1(st) month to 12(th) month. Sera with 1:125 dilution, and peroxidase-conjugated goat anti-human IgG diluted 1:10000 were considered optimum.

RESULTS

To ease reporting the results and due to many similarities only results related to 1(st), 6(th) and 12(th) months were analyzed and sensitivity, specificity plus cut-off were determined for each series separately.

CONCLUSION

Preserving the coated plates, while unblocked at -80°C for 6-8 months is pertinent and functional and in that case, we can be sure the best out put would be applicable.

The present status of human helminthic diseases in Iran

Over the last few decades there have been several marked changes in the human helminthiases found in Iran. Fascioliasis is emerging as an important chronic disease of humans, especially in the northern province of Gilan (where outbreaks in 1989 and 1999 involved >7000 and >10,000 cases, respectively) and, more recently, in the western province of Kermanshah. In contrast, no cases of urinary schistosomiasis, a disease that once affected thousands of individuals in south-western Khuzestan province, have been reported in Iran in recent years, and no cases of dracunculiasis have been seen in the country since the mid-1970s. Approximately 1% of all admissions to surgical wards are attributable to cystic echinococcosis, which is still considered endemic, but only a few cases of alveolar echinococcosis have been recorded. Over the last decade, there appears to have been a generally downward trend in the incidence of intestinal helminthiases in Iran. Recent estimates of the prevalences of ascariasis and strongyloidiasis, for example, lie between just 0.1% and 0.3%, and <1% of the population now appears to be infected with hookworm. In contrast, human infection with Hymenolepis and Enterobius remains relatively common. There have been a few case reports of toxocariasis and a few sero-epidemiological investigations of this disease but problems in accurate diagnosis have prevented good estimates of the general prevalence of this nematode infection. Just nine cases of pentastomiasis (all caused by Linguatula), 12 of dirofilariasis, one of gongylonemiasis, and three of moniliformiasis have been formally recorded in Iran.

Genetic diversity in merozoite surface protein (MSP)-1 and MSP-2 genes of Plasmodium falciparum in a major endemic region of Iran

Merozoite surface protein-1 (MSP-1) and merozoite surface protein-2 (MSP-2) were used to develop vaccines and to investigate the genetic diversity in Plasmodium falciparum malaria in Iran. Nested polymerase chain reaction amplification was used to determine polymorphisms of block 2 of the MSP-1 and the central domain of MSP-2 genes. A total of 67 microscopically positive P. falciparum infected individuals from a major endemic region, southeast Iran, were included in this trial. Nine alleles of MSP-1 and 11 alleles of MSP-2 were identified. The results showed that amplified product from these surface antigen genes varied in size and there was specific pattern for each isolate. Besides, regarding this pattern, 23 multiple infections with at least 2 alleles were observed. While the endemic regions of malaria in Iran is classified in low to moderate group, but extensive polymorphism was observed for each marker and the MSP-2 central repeat was the most diverse that could be considered in designing malaria vaccine.

Comparison of enzyme-linked immunosorbent assay and indirect immunofluorescence assay in the diagnosis of human strongyloidiasis

BACKGROUND

An enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence assay (IFA) were evaluated for serological diagnosis of human strongyloidiasis.

METHODS

Serum specimens obtained from 46 individuals infected with Strongyloides stercoralis, 37 healthy persons and 381 persons with other parasitic infections were tested using an IgG-ELISA that used crude antigen of S. stercoralis filariform larvae and an IFA. Test sera were pre-incubated with antigens from Ascaris, Toxocara and hydatid protoscolices to remove non-specific antibodies.

RESULTS

The sensitivity, specificity, positive predictive value and negative predictive value for ELISA were 93.5%, 96.1%, 72.9% and 99.2%, respectively, and those for IFA were 87%, 90.1%, 49.4% and 98.4%, respectively. Both assays showed false positivity in hydatidosis, ascariasis and toxocariasis; however, this was less common with ELISA.

CONCLUSION

ELISA method using filariform larval antigen may be a sensitive and specific test for human strongyloidiasis, and may be preferable to IFA.

Helminth parasites of the wild boar, Sus scrofa, in Luristan province, western Iran and their public health significance

Seven helminth species were obtained from 12 wild boars (Sus scrofa) during a survey from 2000 to 2001 in Luristan province, western Iran. These species include the cestode larvae Cysticercus tenuicollis (25%), C. cellulosae (8.3%), the nematodes Metastrongylus apri (41.6%), M. pudendotectus (16.6%), M. salmi (8.3%), Trichuris suis (8.3%) and the acanthocephalan Macracanthorhynchus hirudinaceus (41.6%). No trematodes were found. Seven wild boars (58.3%) were identified as having at least one helminth species. A single infection was detected in 16.6% of cases, but a three species infection covered the highest rank (25%). All these helminths have been reported from other areas of Iran including the north, northeast and southwest, but not in Luristan. Among seven helminths identified, at least three species are transmissible to humans. The public health significance of these helminths is discussed.

Comparison of adult somatic and cysteine proteinase antigens of Fasciola gigantica in enzyme linked immunosorbent assay for serodiagnosis of human fasciolosis

Fasciolosis caused by Fasciola hepatica and Fasciola gigantica is one of the major public health problems in the world and in Iran. Considering that stool examination for Fasciola eggs is not a sensitive method and immunodiagnosis methods are more applicable for this purpose, so the present study was conducted to compare the somatic (S) and cysteine proteinase (CP) antigens of F. gigantica in IgG-ELISA to diagnose human fasciolosis. Serum samples obtained from 100 individuals collected during the fasciolosis outbreak in 1999 in the Gilan province of Northern Iran that were coprologically positive for fasciolosis were analyzed by IgG-ELISA. Sera from healthy control individuals, not infected with any parasitic diseases (n=50) and from others with different parasitic infections including hydatidosis (n=40), toxocariosis (n=20), amoebiosis (n=10), and malaria (n=5) were examined as well. The cut-off point for (S) and CP was 0.40 and 0.35, respectively. All 100 individuals that showed clinical manifestations of fasciolosis, were also seropositive using both antigens, whereas all 50 non-infected controls were seronegative, therefore the sensitivity of the test was 100% for both antigens. The specificity of (S) and CP antigens were calculated as 96.9 and 98.4%, respectively. The positive and negative predictive values of the test regarding (S) antigen were 96 and 100%, whereas these values as for CP antigen were 98 and 100% correspondingly. Two individuals with hydatidosis and two with toxocariasis had antibodies that were reactive against (S) antigen, whereas concerning CP antigen, one individual with hydatidosis and another with toxocariasis showed cross-reactivity against it. We have demonstrated that altogether CP antigen provides a more conclusive diagnosis as possessing lower cut-off and enabling better to discriminate between seronegative and seropositive subpopulations.

Diagnosis of human fasciolosis in the Gilan province of Northern Iran: application of cathepsin L-ELISA

Fasciolosis, or liver fluke disease, caused by parasites of the genus Fasciola is emerging as an important disease in man, particularly in countries such as Bolivia, Peru and Egypt. Several outbreaks of this disease recently occurred in the Gilan province of Northern Iran and in 1999 alone over 10000 individuals were infected. Our laboratory recently developed an enzyme linked immunosorbant assay (ELISA) test for diagnosing human fasciolosis in an endemic area of northern Bolivia. The assay was based on the detection of serum antibodies reactive with antigens secreted by the parasite. In the present report we examined the sensitivity and specificity of this ELISA to diagnose 176 patients residing in the Gilan province of Northern Iran. These individuals presented at health clinics with clinical symptoms of fasciolosis and were subsequently positively diagnosed by fecal analysis. The ELISA employed total molecules secreted by the parasites (excretory/secretory, ES, products) and a protease, termed cathepsin L1 (CL1), which was purified from this preparation, as antigen. In addition, the specificity of the assay was investigated using serum from Iranian individuals that were infected with hydatidosis, toxocariasis, amoebiasis, malaria and kalaazar. Using this assay, both CL1 and ES exhibited a sensitivity of 100% (all 176 patients tested positive) and a specificity of 100% and 98.9%, respectively. In conclusion, our standardized diagnostic ELISA for human fasciolosis based on the detection of IgG responses to parasite ES and CL1 would be a valuable tool to diagnosis human fasciolosis in Iran and could be employed in a large survey to determine the prevalence of the disease throughout this region.