A capture ELISA for the diagnosis of visceral leishmaniasis using a monoclonal antibody against a leishmanial urinary antigen

ABSTRACT A capture ELISA system was developed for diagnosis of visceral leishmaniasis (VL) using a monoclonal antibody raised against an antigen previously detected in the urine of VL patients. Urine samples from confirmed VL cases from Yemen, Nepal, Spain, Sudan and Brazil were tested in the capture ELISA in comparison with urine samples from endemic and non-endemic areas along with urine samples from patients with malaria, brucellosis, schistosomiasis and patients with non-infectious diseases. All of VL patient samples from different geographical areas (apart from 2 samples from Brazil) gave a positive result, while no cross-reaction was found with the control samples. The results obtained with the capture-ELISA were compared to those obtained with KAtex, a previously described latex agglutination test, showed that the KAtex and the new ELISA are comparable in terms of specificity (100%) but a better sensitivity (94.1%) was found for the capture-ELISA. Moreover, the capture-ELISA adds a useful quantitative dimension to antigen detection. In addition, the boiling of urine samples, which is necessary for KAtex, was not required in the capture-ELISA. These results suggest that the antigen detection in urine by the new capture ELISA system provides a useful method for diagnosis of VL and fulfils the requirements of a non-invasive method for diagnosis of VL. Iran. Biomed. J. 9 (3): 117-122, 200

Antigen-Based Diagnosis of Human Giardiasis: A Systematic Review and Meta-Analysis

Background: We aimed to present a systematic review and meta-analysis of studies that used antigen-based assays for the diagnosis of human giardiasis. Methods: All the related published literature cited within PubMed, ISI web of science, Google Scholar, Embase, and Scopus, were searched up to December 2021. The search terms, both as MeSH terms and text words, were “Giardia”, “Giardia lamblia”, “Giardia intestinalis", "giardiasis", combined with "diagnosis", "antigen detection", serodiagnosis, or serological diagnosis.  The required data was extracted from the papers. Pooled estimates of sensitivity and specificity were obtained and forest plots and summary receiver operating characteristics (SROC) plots were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).  Results: The search of databases found 1683 papers, of which 46 articles fulfilled our eligibility criteria. The sensitivity of antigen-based methods for the diagnosis of human giardiasis ranged from 45% (95% CI: 31-59%) to 100% (95% CI: 100-100%) and the pooled estimate of sensitivity was 92% (95% CI: 90-93%). The pooled estimated specificity was 97% (95% CI: 96-98%), ranged from 81% (95% CI: 68-89%) to 100% (95% CI: 98-100%). The summary estimate of PPV and NPV were 92 % (95% CI: 90-93%) and 97% (95% CI: 96-98%) respectively. Comparing the performance of the antigen detection assays by region revealed a significant difference in the assay's performances in different regions of the world. Conclusion: The antigen-based detection methods have acceptable and satisfactory performance in the diagnosis of human giardiasis.  The task ahead is to identify more specific target antigens and design simpler, cheaper, and more sensitive methods for the diagnosis of this common worldwide-distributed parasitic infection

Prevalence of Cryptosporidium and risk factors related to cryptosporidiosis in hospitalized children under 5 years of age due to diarrhea (Shahrekord-2005)

& Objective: Cryptosporidium is a cosmopolitan protozoan parasite which is recently known as one of the main causes of diarrhea in children and immunocompromised cases. Majority of studies on this parasite in the last 3 decades focusing on immunocompromised cases has been reported from developed countries and no comprehensive study has evaluated the prevalence and risk factors related to cryptosporidiosis in Iran. This study aimed at investigating the prevalence of Cryptosporidium and risk factors related to ..

Seroprevalence and Molecular Evaluation of Toxoplasmosis in Patients Undergoing Chemotherapy for Malignancies in the Bushehr Province, Southwest Iran

Background: Toxoplasmosis is a life-threatening infection in organ transplant recipients, people receiving corticosteroid or radiation therapy, people with malignancies, and AIDS patients. Objectives: The current study aimed to determine the prevalence of toxoplasmosis in patients receiving chemotherapy for malignancies in the Bushehr province of southwest Iran. Methods: Blood samples were taken from 86 patients who were continuously referred to the chemotherapy center in Bushehr province and evaluated by ELISA to determine anti-Toxoplasma IgG and IgM antibodies. Moreover, a blood buffy coat of each sample was assessed by polymerase chain reaction (PCR), targeting a 529 bp gene of T. gondii. PCR products of the positive samples were sequenced to determine the genotype of the parasite. Results: Anti-Toxoplasma IgG antibodies were detected in the sera of 21 (24.4%) cases. All of the patients were negative for anti- Toxoplasma IgM antibodies. No statistically significant correlation was found between seropositivity to Toxoplasma and duration of chemotherapy or having contact with cats. PCR detected a 529 bp band of T. gondii in the buffy coats of two out of 86 (2.3%) cases. The sequence analysis demonstrated that both cases were 95% identical to type III (VEG strain) of T. gondii. Conclusions: Findings of this study demonstrated the presence of type III T. gondii in the buffy coats of patients undergoing chemotherapy. Given that toxoplasmosis is a life-threatening infection in immunocompromised patients, these patients should be screened for toxoplasmosis before and during chemotherapy to prevent acute toxoplasmosi

Seroprevalence and Molecular Evaluation of Toxoplasmosis in Patients Undergoing Chemotherapy for Malignancies in the Bushehr Province, Southwest Iran

Toxoplasmosis is a life-threatening infection in organ transplant recipients, people receiving corticosteroid or radiation therapy, people with malignancies, and AIDS patients. Objectives: The current study aimed to determine the prevalence of toxoplasmosis in patients receiving chemotherapy for malignancies in the Bushehr province of southwest Iran. Methods: Blood samples were taken from 86 patients who were continuously referred to the chemotherapy center in Bushehr province and evaluated by ELISA to determine anti-Toxoplasma IgG and IgM antibodies. Moreover, a blood buffy coat of each sample was assessed by polymerase chain reaction (PCR), targeting a 529 bp gene of T. gondii. PCR products of the positive samples were sequenced to determine the genotype of the parasite. Results: Anti-Toxoplasma IgG antibodies were detected in the sera of 21 (24.4%) cases. All of the patients were negative for anti- Toxoplasma IgM antibodies. No statistically significant correlation was found between seropositivity to Toxoplasma and duration of chemotherapy or having contact with cats. PCR detected a 529 bp band of T. gondii in the buffy coats of two out of 86 (2.3%) cases. The sequence analysis demonstrated that both cases were 95% identical to type III (VEG strain) of T. gondii. Conclusions: Findings of this study demonstrated the presence of type III T. gondii in the buffy coats of patients undergoing chemotherapy. Given that toxoplasmosis is a life-threatening infection in immunocompromised patients, these patients should be screened for toxoplasmosis before and during chemotherapy to prevent acute toxoplasmosis

Molecular and Morphological Characterization of Fasciola

The current study aimed to find out the morphometric and genotypic divergences of the flukes isolated from different hosts in a newly emerging focus of human fascioliasis in Iran. Adult Fasciola spp. were collected from 34 cattle, 13 sheep, and 11 goats from Kohgiluyeh and Boyer-Ahmad province, southwest of Iran. Genomic DNA was extracted from the flukes and PCR-RFLP was used to characterize the isolates. The ITS1, ITS2, and mitochondrial genes (mtDNA) of NDI and COI from individual liver flukes were amplified and the amplicons were sequenced. Genetic variation within and between the species was evaluated by comparing the sequences. Moreover, morphometric characteristics of flukes were measured through a computer image analysis system. Based on RFLP profile, from the total of 58 isolates, 41 isolates (from cattle, sheep, and goat) were identified as Fasciola hepatica, while 17 isolates from cattle were identified as Fasciola gigantica. Comparison of the ITS1 and ITS2 sequences showed six and seven single-base substitutions, resulting in segregation of the specimens into two different genotypes. The sequences of COI markers showed seven DNA polymorphic sites for F. hepatica and 35 DNA polymorphic sites for F. gigantica. Morphological diversity of the two species was observed in linear, ratios, and areas measurements. The findings have implications for studying the population genetics, epidemiology, and control of the disease

Protozoan Parasites of Rodents and Their Zoonotic Significance in Boyer-Ahmad District, Southwestern Iran

Backgrounds. Wild rodents are reservoirs of various zoonotic diseases, such as toxoplasmosis, babesiosis, and leishmaniasis. The current study aimed to assess the protozoan infection of rodents in Boyer-Ahmad district, southwestern Iran. Materials and Methods. A total of 52 rodents were collected from different parts of Boyer-Ahmad district, in Kohgiluyeh and Boyer-Ahmad province, using Sherman live traps. Each rodent was anesthetized with ether, according to the ethics of working with animals, and was dissected. Samples were taken from various tissues and stool samples were collected from the contents of the colon and small intestines. Moreover, 2 to 5 mL of blood was taken from each of the rodents and the sera were examined for anti-Leishmania antibodies, by ELISA, or anti-T. gondii antibodies, by modified agglutination test (MAT). DNA was extracted from brain tissue samples of each rodent and PCR was used to identify the DNA of T. gondii. Results. Of the 52 stool samples of rodents studied by parasitological methods, intestinal protozoa infection was seen in 28 cases (53.8%). From 52 rodents, 19 (36.5%) were infected with Trichomonas, 10 (19.2%) with Giardia muris, and 11 (21.2%) with Entamoeba spp. Also, 10 cases (19.2%) were infected with Blastocystis, 3 (5.8%) were infected with Chilomastix, 7 (13.5%) were infected with Endolimax, 1 (1.9%) was infected with Retortamonas, 3 (5.77%) were infected with T. gondii, and 6 (11.54%) were infected with Trypanosoma lewisi. Antibodies to T. gondii were detected in the sera of 5 (9.61%) cases. Results of the molecular study showed T. gondii infection in 3 (5.77%) of the rodents. Findings of this study showed that rodents in Kohgiluyeh and Boyer-Ahmad province, southwestern Iran, are infected with several blood and intestinal parasites; some of them might be potential risks to residents and domestic animals in the region

Molecular and Microscopic-Based Characterization of Plasmodium

Despite malaria control programs in recent years, malaria transmission has not been eliminated in Iran. Molecular techniques including PCR, which has proved more sensitive and specific than microscopic examination methods, help to detect infection in low levels of parasitemia and mixed infections. Main our objectives were setting up nested PCR for detection of malaria and evaluating PCR based on plasmodia DNA from blood smears in Fars province, the comparison of this method with traditional microscopy and also evaluate the data in comparison with its neighboring province, Hormozgan. A total of 149 malaria positive samples including 116, 19, and 14 samples from Shiraz, Jask, and Lengeh ports were utilized in this study, respectively. Blood slides were prepared for microscopic observation. DNA from thin smears was extracted and nested PCR was analyzed using rPLU5 and rPLU6 for genus specification, rFAL1, rFAL2, and rVIV1, rVIV2 for P. falciparum and P. vivax detection, respectively. The results showed that 126 (84.6%), 16 (10.7%), and 7 (4.7%) out of 149 cases were positive for P. vivax, P. falciparum, and mixed infections, respectively, by microscopy. The PCR indicated that 95 (63.7%), 15 (10.1%), and 22 (14.8%) cases were infected with P. vivax, P. falciparum, and mixed mentioned species, respectively, and 17 (11.4%) cases were uninfected. Our results confirmed the considerable sensitivity of nested PCR for detection of the mixed infections. Simultaneous application of PCR even based on microscopy slides can facilitate access to the highest level of confidence in malaria researches

Cystic Echinococcosis: Knowledge, Attitude, and Practices (KAP) among Surgically Operated Cases in Fars Province, Southern Iran

Introduction. Cystic echinococcosis (CE) is a neglected zoonotic disease caused by Echinococcus granulosus with major health and economic burden. The information on how the community members perceive the disease is crucial in order to recommend an effective preventive and control plan. The current study is aimed at finding out knowledge, attitude, and practices (KAP) of surgically operated cases of hydatid cyst in educational hospitals of Shiraz in Fars Province, southern Iran, toward the CE. Methods. A cross-sectional survey was conducted among 180 CE patients who underwent surgery due to CE. Using a well-designed questionnaire, a telephone-based survey was carried out to collect the data. The contents of the questionnaire included basic personal information and questions related to the participants’ knowledge, attitude, and behavioral patterns toward CE. Univariate and then multivariate linear regression analyses were used to identify factors associated with the KAP. Unstandardized regression coefficients (β) and odds ratios (ORs) and their 95% confidence intervals (CIs) were used to quantify the associations between variables and KAP. Results. A total of 180 CE patients with a mean age of 35.64 (±17.59) years were recruited. The mean score of participant’s knowledge was 8.7 (SD=2.8, range: 0-17), whereas these scores were 1.3 (SD=0.7, range 0-2) for attitude and 1.2 (SD=1.0, range 0-4) for practice. Findings of the study demonstrated that 20 of the participants (11.1%) had good knowledge towards CE, 82 (45.6%) demonstrated a positive attitude, and 57 (47.5%) without having dogs demonstrated a good practice towards CE (score=2/2), while from 60 dog owners, only 7 (11.6%) participants demonstrated good practice (score 3 and 4/4). Factors that were associated with knowledge were age (OR=−0.49, P value = 0.001) and educational level (OR=0.668, P value = 0.001), where higher age was associated with lower knowledge and also higher educational levels were associated with higher knowledge regarding hydatid cyst. Regarding attitude, only living location had a significant association with participants’ attitude where those who were living in urban areas demonstrating a more positive attitude towards CE (OR=0.261, P value = 0.022). The practice of the participants was grouped into dog owners and participants with no dogs, in which among participants who did not own a dog, those living in urban areas demonstrating weaker practice towards CE (OR=−0.491, P value>0.001). Moreover, a lack of counseling of patients after the surgery on how to prevent reinfection was noticed. Conclusion. Findings of the study revealed that the CE patients in southern Iran had poor knowledge and attitude toward the disease, and their practice may help in maintaining the disease in the community. Health education is highly needed to increase community awareness and to prevent and control this neglected parasitic infection in the area