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Background: The sensitivity of parasitological and molecular methods is unsatisfactory for the diagnosis of strongyloidiasis, and serological techniques are remaining as the most effective diagnostic approach. The present study aimed to design and produce a chimeric recombinant antigen from Strongyloides stercoralis immunoreactive antigen (SsIR) and Ss1a antigens, using immune-informatics approaches, and evaluated its diagnostic performance in an ELISA system for the diagnosis of human strongyloidiasis. Methodology/Principal findings: The coding sequences for SsIR and Ss1a were selected from GenBank and were gene-optimized. Using bioinformatics analysis, the regions with the highest immunogenicity that did not overlap with other parasite antigens were selected. The chimeric recombinant antigen SsIR- Ss1a, was constructed. The solubility and physicochemical properties of the designed construct were analyzed and its tertiary structures were built and evaluated. The construct was expressed into the pET-23a (+) expression vector and the optimized DNA sequences of SsIR-Ss1a (873 bp) were cloned into competent E. coli DH5α cells. Diagnostic performances of the produced recombinant antigen, along with a commercial kit were evaluated in an indirect ELISA system, using a panel of sera from strongyloidiasis patients and controls. The physicochemical and bioinformatics evaluations revealed that the designed chimeric construct is soluble, has a molecular with of 35 KDa, and is antigenic. Western blotting confirmed the immunoreactivity of the produced chimeric recombinant antigen with the sera of strongyloidiasis patients. The sensitivity and specificity of the indirect ELISA system, using the produced SsIR-Ss1a chimeric antigen, were found to be 93.94% (95% CI, 0.803 to 0.989) and 97.22% (95% CI, 0.921 to 0.992) respectively. Conclusions/Significance: The preliminary findings of this study suggest that the produced SsIR-Ss1a chimeric antigen shows promise in the diagnosis of human strongyloidiasis. However, these results are based on a limited panel of samples, and further research with a larger sample size is necessary to confirm its accuracy. The construct has potential as an antigen in the ELISA system for the serological diagnosis of this neglected parasitic infection, but additional validation is required. Author summary: In our study, we aimed to improve the diagnosis of strongyloidiasis, a parasitic infection that is often difficult to detect with current methods. Traditional parasitological and molecular techniques have limitations in sensitivity, making it challenging to accurately diagnose this condition. To address this, we designed a new diagnostic tool using a chimeric recombinant antigen, combining two specific antigens from the parasite Strongyloides stercoralis. We used advanced bioinformatics to select the most immunogenic regions of these antigens, ensuring they did not overlap with other parasite proteins. This chimeric antigen was then produced and tested for its diagnostic performance in an ELISA system. Our results showed that the new chimeric antigen is both soluble and highly antigenic; meaning it effectively triggers an immune response. When tested with sera samples from patients with strongyloidiasis, the ELISA system using our chimeric antigen demonstrated high sensitivity (93.94%) and specificity (97.22%), indicating it could accurately identify infected individuals. These findings are promising, suggesting that our chimeric antigen could be a valuable tool for diagnosing strongyloidiasis. However, further research with a larger sample size is needed to confirm its effectiveness. If validated, this new diagnostic approach could significantly improve the detection and management of this neglected parasitic infection, benefiting both patients and healthcare providers. [ABSTRACT FROM AUTHOR]

Background: Toxocara canis is one of the most important causes of animal toxocariasis with global distribution. We aimed to find out the seroprevalence of toxocariasis in dogs in a rural area in Fars Province, south of Iran. Methods: Dogs blood samples were collected from 60 dogs in three rural areas in the Sar Mashhad region, Fars Province. Dog sera were evaluated for anti-Toxocara antibodies by an indirect ELISA method. The association between the seropositivity and age, gender, and the sampling location were statistically evaluated. Results: Serological assay detected anti-Toxocara antibodies in sera of 32 out of 60 dogs, corresponding to a seroprevalence of 53.3%. The rate of seropositivity was higher in the male dogs. The rate of seropositivity was higher in old dogs. This rate increased with increasing age, however, the association between age and Toxocara seropositivity was not statistically significant. Conclusion: The high prevalence of Toxocara infection in dogs in the current study area confirms that infected dogs are an important source of Toxocara infection for their owners and people who are in close contact with these animals, especially children. [ABSTRACT FROM AUTHOR]

Background Application of chemotherapeutics in cancer patients may provide an immunosuppressive milieu, favourable for parasitic infections. Giardia duodenalis is an important zoonotic intestinal parasite responsible for diarrhoea in humans worldwide. Methods The present systematic review and meta-analysis was conducted to estimate the prevalence of G. duodenalis and respective odds ratios (ORs) in cancer patients around the globe. Four online databases—PubMed, Scopus, Web of Science and Google Scholar—were carefully explored for relevant literature without time limitation until 28 November 2020. Meta-analysis was done based on a random effects model to pool the estimations and define 95% confidence intervals (CIs). Results The overall weighted prevalence of G. duodenalis infection in cancer patients was calculated to be 6.9% (95% CI 0.5 to 9.3) globally, based on data from 32 studies. Although not statistically significant, eight case–control studies revealed that cancer patients were 1.24 times (95% CI 0.66 to 2.31; p=0.501) more exposed to G. duodenalis infection than healthy controls. Moreover, the prevalence of infection was not significantly associated with quantitative variables, including publication year (regression coefficient −0.0135, p=0.578), sample size (regression coefficient −0.0007, p=0.074) and human development index (regression coefficient −1.6263, p=0.419). Also, subgroup analysis of the pooled G. duodenalis infection was performed for publication year, World Health Organization regions, countries, continents, cancer types and country income. Conclusions Altogether, the epidemiology of G. duodenalis infection and its associated risk factors in immunocompromised individuals, especially cancer patients, is still open to question and deserves comprehensive investigations. [ABSTRACT FROM AUTHOR]