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Parasitologia, Volume 4, Issue 2 (June 2024) – 6 articles

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12 pages, 845 KiB  
Article
Sensitivity Assessment of a Multiplex and Real-Time PCR Protocols for the Detection of Malaria in External Quality Control Samples in the Malaria Reference Center in Greece
by Nikolaos Tegos, Christos Goumenopoulos, Anastasia Mpimpa, Vasilios Papavasilopoulos, Stavroula Beleri and Eleni Patsoula
Parasitologia 2024, 4(2), 150-161; https://doi.org/10.3390/parasitologia4020013 - 17 May 2024
Viewed by 287
Abstract
Background: Accurate malaria diagnosis constitutes a challenging task, necessitating the need for the implementation of targeted and effective diagnostic tools. The purpose of the current study was to evaluate the effectiveness of two different molecular methodologies in terms of sensitivity for the detection [...] Read more.
Background: Accurate malaria diagnosis constitutes a challenging task, necessitating the need for the implementation of targeted and effective diagnostic tools. The purpose of the current study was to evaluate the effectiveness of two different molecular methodologies in terms of sensitivity for the detection of External Quality Assessment (EQA) Plasmodium samples. Methods: A total of 104 lyophilized blood samples from 14 different UK-NEQAS (National External Quality Assessment Site) (2016–2021) and eight WHO-NEQAS distributions (2017–2020) were analyzed. An in-house multiplex PCR protocol, followed by single target real-time PCR protocols for all five Plasmodium species, was implemented. Results: The multiplex PCR had a success rate of 10/16 and 20/28 for P. vivax and P. falciparum species, respectively. On the other hand, the respective results for real-time PCR had a success rate of 13/16 (P. vivax), 28/28 (P. falciparum), 5/8 (P. malariae), 8/10 (P. ovale), and 10/14 (P. knowlesi). Plasmodium falciparum samples displayed the highest sensitivity of detection, 0.02 parasites/μL. Plasmodium vivax samples displayed a 0.1 parasites/μL cutoff value, greater than the respective value for whole blood samples, while P. ovale species displayed a respective cutoff value of 0.05 parasites/μL. Due to the limited number of tested samples, data obtained for P. malariae and P. knowlesi species samples were inconclusive. Conclusions: Real-time PCR comprises a credible molecular methodology in terms of sensitivity assessment and detection of low parasitemia levels of Plasmodium sp. in EQA lyophilized blood samples. Full article
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13 pages, 1253 KiB  
Article
The Influence of Flock Variation, Sample Size, Flock Size and Mean Egg Count on the Accuracy and Precision of the Estimated Mean Egg Count
by Michael Stear, Sarah Preston, David Piedrafita, George Cullimore and Katarzyna Donskow-Łysoniewska
Parasitologia 2024, 4(2), 137-149; https://doi.org/10.3390/parasitologia4020012 - 30 Apr 2024
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Abstract
The control of parasitic nematode infection in sheep and other animals is threatened by the evolution of drug resistance in parasite populations. One recommendation to delay the onset of drug resistance is to estimate the flock mean faecal egg counts by sampling a [...] Read more.
The control of parasitic nematode infection in sheep and other animals is threatened by the evolution of drug resistance in parasite populations. One recommendation to delay the onset of drug resistance is to estimate the flock mean faecal egg counts by sampling a subpopulation and to treat sheep only when egg counts are high. However, there is little research on the accuracy and precision of estimates of the flock mean obtained from samples. In silico sampling was used to quantify the influence of flock variation, sample size, flock size and mean egg count on the accuracy and precision of the estimated mean egg count. Commonly used and recommended sampling schemes gave alarmingly imprecise estimates of the true flock means. Simply providing a point estimate of the flock egg count can be seriously misleading. Therefore, quantiles were provided for the proportion of estimates in a plausible scenario that is likely to require treatment. It may be more informative to use these quantiles to predict the probability that the true flock mean is sufficiently high to consider treatment. Full article
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8 pages, 1211 KiB  
Article
Data on Demodex Ectoparasite Infestation in Patients Attending an Outpatient Clinic in Greece
by Anastasia Kargadouri, Stavroula Beleri and Eleni Patsoula
Parasitologia 2024, 4(2), 129-136; https://doi.org/10.3390/parasitologia4020011 - 26 Apr 2024
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Abstract
Demodex mites are acari, common ectoparasites of humans and other mammalian pilosebaceous units. Demodicosis occurs when mites overpopulate the skin, causing several skin disorders. Our aim was to investigate the prevalence of demodicosis in patients with suspicious clinical features, such as cheek redness, [...] Read more.
Demodex mites are acari, common ectoparasites of humans and other mammalian pilosebaceous units. Demodicosis occurs when mites overpopulate the skin, causing several skin disorders. Our aim was to investigate the prevalence of demodicosis in patients with suspicious clinical features, such as cheek redness, itching, and skin sensitivity, who presented at the outpatient clinic of the Andreas Syggros Dermatology Hospital in Greece. We studied 184 individuals aged between 18 and 97 years and analyzed the content of pilosebaceous units by microscopy to determine the density of Demodex mites. Samples were evaluated as positive when Demodex spp. densities equaled or exceeded 5 mites per square cm. Sixty-six percent of the examined subjects were positive for demodicosis. The age distribution was statistically normal (p = 0.2), and the median age was 51.29 years. Seventy percent of the patients were females, and 30% were males, while 64.46% of the demodicosis-positive individuals were females, and 35.54% were males. We observed a rise in the percentage of males as the age of the patients increased. Demodicosis can be a challenging disease because it presents apart from the typical symptoms, with a variety of nonspecific symptoms mimicking other dermatological skin conditions. Therefore, it is important to investigate Demodex spp. in patients who present with common facial dermatological diseases to improve treatment results. Further studies could contribute to a better understanding of the pathogenic role of Demodex mites and how this role is affected by mite density, host sex and age. Full article
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28 pages, 505 KiB  
Review
Transmission Modelling for Human Non-Zoonotic Schistosomiasis Incorporating Vaccination: Guiding Decision- and Policymaking
by Ursula Panzner
Parasitologia 2024, 4(2), 101-128; https://doi.org/10.3390/parasitologia4020010 - 15 Apr 2024
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Abstract
Schistosomiasis, acquired by skin-penetrating cercariae of dioecious digenean schistosomes during freshwater contact, afflicts nearly 260 and 440 million people with active infections and residual morbidity, respectively. About 10 million women at reproductive age contract schistosomiasis during gestation every year. Acute schistosomiasis is characterized [...] Read more.
Schistosomiasis, acquired by skin-penetrating cercariae of dioecious digenean schistosomes during freshwater contact, afflicts nearly 260 and 440 million people with active infections and residual morbidity, respectively. About 10 million women at reproductive age contract schistosomiasis during gestation every year. Acute schistosomiasis is characterized by pre-patent pro-inflammatory CD4+ T-helper 1 or CD4+ Th1/T-helper 17 reactivity against immature schistosomulae. Chronic schistosomiasis is dominated by post-patent anti-inflammatory CD4+ T-helper 2 reactivity against ova epitopes. Flukes co-exist in immunocompetent definitive hosts as they are capable of evading their defense mechanisms. Preventive measures should be complemented by vaccination, inducing long-term protection against transmission, infection, and disease recurrence, given the latest advancements in schistosomal vaccines. Vaccines become pivotal when considering constraints of chemotherapy, i.e., lack of protection against re-infection, and evolving resistance or reduced sensitivity. Transmission models for human non-zoonotic schistosomiasis incorporating vaccination available in PubMed, Embase and Web of Science up to 31 December 2023 are presented. Besides conceptual model differences, predictions meant to guide decision- and policymaking reveal continued worm harboring that facilitates transmission besides residual infections. In addition, increased susceptibility to re-infection and rebound morbidity, both shifted to later life stages following the intervention, are forecasted. Consequently, a vaccination schedule is pivotal that considers the optimal age for initial immunization, i.e., pre-schoolchildren or schoolchildren in a cohort-based or population-based manner, while incorporating potential non-adherers promoting ongoing transmission. Longevity over magnitude of vaccine protection to antigenic schistosomal moieties is crucial. Accounting for pre-acquired immunity from natural exposure, in utero priming in addition to herd immunity, and induced by chemotherapy is crucial. Combining, as a multi-component approach, long-term effects of vaccination with short-term effects of chemotherapy as regular repeated vaccine-linked therapy seems most promising to achieve WHO’s endpoints of transmission elimination and morbidity control. Full article
2 pages, 166 KiB  
Editorial
Micro–Nanoplastics as Potential Carriers of Dioxins and Toxoplasma gondii in Patients with Carotid Atheromas
by Giovanni Di Guardo
Parasitologia 2024, 4(2), 99-100; https://doi.org/10.3390/parasitologia4020009 - 14 Apr 2024
Viewed by 337
Abstract
A recent major study has shown that there is an increased risk of myocardial infarction, stroke and lethal outcomes in patients affected by carotid atheromas that contain micro-nanoplastics (MNPs) compared to subjects that do not have MNPs in their lesions [...] Full article
8 pages, 1296 KiB  
Brief Report
Evaluation of a Commercial Serum Competitive Enzyme-Linked Immunosorbent Assay for Detection of Neospora caninum-Specific Antibodies in Raw Milk of Ruminants
by Ragab M. Fereig, Sarah A. Altwaim and Caroline F. Frey
Parasitologia 2024, 4(2), 91-98; https://doi.org/10.3390/parasitologia4020008 - 27 Mar 2024
Viewed by 546
Abstract
Bovine neosporosis is an infection caused by the protozoan parasite Neospora caninum and has substantial veterinary hazards. Neosporosis cannot be controlled by vaccination or chemotherapy. Thus, accurate diagnosis followed by isolation and culling of infected animals is regarded as the most efficient method [...] Read more.
Bovine neosporosis is an infection caused by the protozoan parasite Neospora caninum and has substantial veterinary hazards. Neosporosis cannot be controlled by vaccination or chemotherapy. Thus, accurate diagnosis followed by isolation and culling of infected animals is regarded as the most efficient method of control. In vivo diagnosis often relies on serologic testing of the animals, and milk represents a non-invasive and easy-to-collect sample matrix. However, indirect enzyme-linked immunosorbent assay (ELISA) specifically designed for antibody detection in milk are sometimes not easily available and it is tempting to use ELISA kits that are originally designed for use in serum in milk samples instead. Herein, we evaluated a widely used commercial ELISA (ID Screen® Neospora caninum competition Multispecies ELISA (ID. Vet, Grabels, France)), developed for detection of N. caninum antibodies in serum samples, for its performance on milk samples. Milk samples from dairy ruminants (cows, buffaloes, sheep, and goats; n = 149) were tested in parallel with the serum ELISA and a commercial milk ELISA as a standard test (Neospora caninum Milk Competitive ELISA, ID. Vet, Grabels, France). The detected prevalence values were 28.2% (42/149), 17.4% (26/149), and 17.4% (26/149) using milk ELISA, serum ELISA, and both ELISAs, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value for the serum ELISA used with milk samples were 61.9%, 100%, 100%, and 87%, respectively. The agreement and kappa value between the two ELISAs were 89.3% and 0.70, respectively, suggesting substantial agreement. High values of Pearson correlation coefficient (0.904, p ≥ 0.0001) and area under the receiver operating characteristic (ROC) curve (0.789, p ≥ 0.0001) demonstrated the high diagnostic performance of the serum ELISA in milk samples. Also, a Bland–Altman Plot and histogram describing the frequency of distribution of ELISA optical densities confirmed the high agreement of both serum and milk ELISAs. The current results revealed the high specificity but moderate sensitivity of the serum ELISA used for milk samples compared with the milk ELISA. However, the excellent positive predictive value of the serum ELISA makes it an alternative option in case of the unavailability of milk ELISAs. With this study, we provided additional evidence that a widely used serum ELISA test kit may also be used for the detection of N. caninum antibodies in milk samples. Full article
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