Parasitic Source Research Articles

Method of determining the coordinates of a low altitude object under the conditions of using several radio signals.

Currently, in large cities, there is a steady tendency to increase the spatial density of telecommunication systems. The saturation of the radio spectrum with analog and digital systems used to solve the problems of radio communication and television allows to improve the technologies of semi-active radar detection and determination of the coordinates of a low-altitude object on their basis. Conducting radar surveillance using non-radar radar transmitters is often called semi-active radar using extraneous or parasitic radiation sources. The advantages of such systems are the minimization of deployment costs, low operating energy costs, low probability of malfunctioning, stealth of the fact of operation, environmental friendliness, and the absence of requirements for the allocation of radio frequency resources. Relatively high heights of antennas of communications and television transmitters with the existing radiated power create favorable conditions for detecting low-altitude objects. Digital signals of modern telecommunication systems have a spectrum width that provides acceptable resolution and accuracy of measuring the total distance and angular coordinates [20; 21]. In the general case, systems of this type are a multi-position system consisting of one or more radiation sources and one or more receiving positions spread in space [22; 23]. The paper gives a general description of the proposed method of determining the coordinates of an aerial object at low altitude under the conditions of propagation of several beams of radio signals. The method and its technical solution capable of determining the coordinates of an unauthorized low-altitude object under the conditions of the existence of several rays of radio signal propagation are defined, and the algorithm of its operation necessary for the technical implementation of the proposed method is presented. The paper considers options for determining the coordinates of aerial objects with different composition of primary coordinate measurements and the number of receiving points. The accuracy of determining the location of the object for multi-position radio systems of this type was evaluated under the conditions of the existence of several beams of radio signal propagation in the developed model, taking into account the number of received signals and their measurement errors.

Application of Q4 Strain Gradient Notation Finite Element Method (SGN-FEM) in Level Set Optimization Using Radial Basis Functions

The Strain Gradient Notation Finite Element Method (SGN-FEM) employs physically interpretable polynomials in the development of finite elements, allowing for the precise identification and subsequent elimination of parasitic shear sources, which cause shear locking. The element is corrected a priori, during development, by simply removing the spurious terms from the shear strain polynomials.The Level Set Method (LVM) is an optimization technique widely employed in topology optimization to minimize the compliance of structures. This method consistently provides clear boundary and geometry information during the optimization process, giving it inherent advantages in solving boundary and geometry-related problems.While numerous studies investigate different approaches to calculate level set optimization, there are fewer studies evaluating how the finite element technique contributes to the analysis. Considering this, this paper presents the application of Q4 SGN-FEM in optimization studies using LVM to minimize the compliance of a two-dimensional linear elastic structure. The differences obtained when using the SGN-FEM model are investigated. The parametrized level set method, as defined in Wei et al. (2018), is utilized alongside SGN-FEM to conduct the study. The model is validated through comparison with other studies, demonstrating that SGN-FEM proves to be a viable alternative for conducting optimization studies using the level set method.

Knowledge, attitudes, and practices of government workers on zoonotic parasites in pet animals: a study in Central Gondar Zone, Ethiopia

BackgroundParasitic zoonoses are infections transmitted between vertebrate animals and humans, posing serious public health risks and significant economic consequences. The study aimed at assessing government workers' knowledge, attitudes, and practices (KAP) regarding zoonotic parasites of pet animals in Ethiopia's central Gondar zone.MethodsA cross-sectional study was carried out in selected towns of Central Gondar Zone, Northwest Ethiopia from January 2022 to August 2022. Four hundred randomly selected government employees participated in the study. Data were collected through semi-structured questionnaire administered by face-to-face interview. The chi-squared (χ2) was calculated for association and p-value less than 0.05 was considered as significant.ResultsA 57.25% of respondents were males and 42.75% were females. Most of the respondents, 67.5%, had completed college/university education. About 60% of the respondents had 'high knowledge', 57.25% had 'positive attitude', and 73% had 'good practice' regarding pet animals as a source of zoonotic parasites. The chi-square analysis revealed a significant discrepancy (p < 0.05) between knowledge with sex, educational level, and position in the house. The attitude level was significantly associated (p < 0.05) with educational level, religious view, and service year. Significant association was also observed (p < 0.05) between practice level of the respondents and educational level and marital status. The study also showed a significant association between knowledge and attitude (χ2 = 40.4, p ≤ 0.001), knowledge and practice (χ2 = 34.9, p ≤ 0.001), and attitude and practice (χ2 = 12.76, p = 0.013) of the respondents.ConclusionAlthough our results revealed that more than half of the participants had good knowledge, attitudes, and practices regarding zoonotic parasites of pet animals, enhanced routine hygienic practices and regular awareness creation programs are recommended to bridge existing gaps.

Persistent carriage of subpatent Plasmodium falciparum parasites associated with clinical malaria in a low transmission area in Senegal

ObjectivesIn low malaria transmission areas, the elimination of the disease has been hampered partly by the existence of a reservoir of subpatent Plasmodium falciparum infections within communities. This reservoir, often undetected, serves as a source of parasites and contributes to ongoing transmission and clinical malaria cases. MethodsThis study, spanning a period of 9 years from June 2014 to December 2022, examined individual variations and long-term subpatent P. falciparum carriage in two matched cohorts of 44 individuals each living in Dielmo village in the Sudanian area of Senegal. Biannual blood samples, collected in June/July and December of each year, underwent P. falciparum diagnosis by quantitative polymerase chain reaction. QGIS and R analytical tools were used to map infections, assess the occurrence and clustering of subpatent and clinical P. falciparum infections, and determine the risk of infection in the vicinity of asymptomatic P. falciparum carriers. ResultsThe point frequency and long-term P. falciparum carriage were significantly higher among the quantitative polymerase chain reaction (qPCR) positive cohort compared to the negative cohort across the 16 cross-sectional surveys analyzed in this study (19.76% vs 10.99%, P-value <0.001). Asymptomatic carriage events in qPCR-positive group were 18.86 ± 1.72% and significantly greater (P-value = 0.001) than in the qPCR-negative group (11.32 ± 1.32%). The relative risk of P. falciparum infection or clinical malaria calculated with a 95% confidence interval significantly increased in the vicinity of infected individuals and was 1.44 (P-value = 0.53) and 2.64 (P-value = 0.04) when at least one individual in the direct (household) or indirect (block of households) vicinity is infected, respectively. The risk increased to 3.64 (P-value <0.001) if at least 1/5 of individuals in the indirect vicinity were P. falciparum-infected. ConclusionsThe study provides a detailed qualitative and quantitative analysis of the asymptomatic P. falciparum reservoir and its temporal and spatial dynamics within two subgroups of P. falciparum-infected and non-infected individuals in Dielmo village. It identified high-risk populations known as “hotpops” and hotspots that could be targeted by innovative interventions to accelerate the elimination of malaria in Dielmo village.

Pet chinchillas (Chinchilla lanigera): Source of zoonotic Giardia intestinalis, Cryptosporidium ubiquitum and microsporidia of the genera Encephalitozoon and Enterocytozoon

The domestic chinchilla (Chinchilla lanigera) is kept as a pet and previous studies suggest that it may play an important role as a source of zoonotic parasites, including Giardia intestinalis, Cryptosporidium spp. and microsporidia. In this study, we examined the occurrence and genetic diversity of above mentioned parasites in pet chinchillas in the Czech Republic by PCR/sequencing of the 18S rRNA, TPI, and ITS genes. Of 149 chinchillas from 24 breeders, 91.3 % were positive for G. intestinalis, 8.1 % for Cryptosporidium spp., 2.0 % for Encephalitozoon spp., and 5.4 % for E. bieneusi. Molecular analyses revealed presence of G. intestinalis assemblage B, C. ubiquitum (XIIa family), E. bieneusi genotypes D, SCF2, and, CHN-F1, and E. intestinalis. The infection intensity of G. intestinalis determined by qRT-PCR reached up to 53,978 CPG, C. ubiquitum up to 1409 OPG, E. intestinalis up to 1124 SPG, and E. bieneusi up to 1373 SPG. Only two chinchillas with C. ubiquitum and five with G. intestinalis had diarrhoea at the time of the screening. Three chinchillas in the long-term study were consistently positive for G. intestinalis, with intermittent excretion of C. ubiquitum, E. intestinalis, and E. bieneusi over 25 weeks. The findings indicate that chinchillas are frequently infected with zoonotic parasitic protists, but that these infections rarely show clinical signs. The lack of visible signs could reduce the vigilance of pet owners when handling their chinchillas, increasing the risk of transmission within breeding groups and possibly to humans.

Parasitism with Protozoa and Monogeneans in Fish from the Natural Waters of Romania.

Parasitism by protozoa and monogenean flatworms in freshwater fish from Romania was studied by collecting and examining samples from two major river systems there: 183 fish from 17 species from the Olt River and its tributaries; and 155 fish from 16 species from the Mureș River and its tributary, Târnava Mare. The average rates of parasitism in the samples from the two rivers and their tributaries were as follows: Ichthyiophthirius multifiliis (2%), Trichodina spp. (21%), Apiosoma spp. (18%), Mixobolus spp. (8%), Dactylogyrus spp. (9%), and Gyrodactylus spp. (10%). The number of parasite species varied from one river to another. I. multifiliis was found in only 3 fish species, Trichodina spp. in 13 species, Glosatella spp. in 6 species, and Mixobollus spp., Dactylogyrus spp., and Gyrodactylus spp. in 7 different species each. The highest number of parasite species (six) were identified in the European chub (Squalius cephalus) and schneider (Alburnoides bipunctatus), which seem more susceptible to parasitic infections. The aquatic environment of these rivers may represent a source of parasites for fish from neighboring countries through which these rivers pass.

Epidemiological investigation of Entamoeba in wild rhesus macaques in China: A novel ribosomal lineage and genetic differentiation of Entamoeba nuttalli

Wild rhesus macaques are a potential source of zoonotic parasites for humans, and Entamoeba spp. are common intestinal parasites. To investigate the prevalence of Entamoeba in wild rhesus macaques in China and explore the genetic differentiation of the potentially pathogenic species Entamoeba nuttalli, a total of 276 fecal samples from five populations at high altitudes (HAG, 2,800–4,100 m above sea level) and four populations at low altitudes (LAG, 5–1,000 m above sea level) were collected. PCR methods based on the ssrRNA gene were used to detect Entamoeba infection. Genotyping of E. nuttalli was performed based on six tRNA-linked short tandem repeat (STR) loci for further genetic analyses. The results revealed that Entamoeba infection (69.2%) was common in wild rhesus macaques in China, especially in LAG which had a significantly higher prevalence rate than that in HAG (P < 0.001). Three zoonotic species were identified: Entamoeba chattoni (60.9%) was the most prevalent species and distributed in all the populations, followed by Entamoeba coli (33.3%) and Entamoeba nuttalli (17.4%). In addition, a novel Entamoeba ribosomal lineage named RL13 (22.8%) was identified, and phylogenetic analysis revealed a close genetic relationship between RL13 and Entamoeba. hartmanni. Genotyping of E. nuttalli obtained 24 genotypes from five populations and further analysis showed E. nuttalli had a high degree of genetic differentiation (FST > 0.25, Nm < 1) between the host populations. The result of analysis of molecular variance (AMOVA) revealed that observed genetic differences mainly originate from differences among populations (FST = 0.91). Meanwhile, the phylogenetic tree showed that these genotypes of E. nuttalli were clustered according to geographical populations, indicating a significant phylogeographic distribution pattern. Considering the potential pathogenicity of E. nuttalli, attention should be paid to its risk of zoonotic transmission.

Hygiene activity of bees in certain territories of Ukraine

The main results of the evaluation of the hygienic activity of bees are highlighted and it is assumed that pollution affects the behavioral patterns of bees and the general protective immune response of the body to the penetration of infection. After all, in Kharkiv, Sumy and Mykolaiv regions, an increased level of pollution was noted in connection with the approach to the zone of hostilities, in particular, the recording of flights to the territory of the apiary, shelling and the movement of heavy military equipment. We assumed that the weakening of the resistance of honey bees to diseases and the deterioration of the general immune response of the body may occur as a result of contamination of the natural environment, including feed, pollen and nectar, with various toxic substances. These substances can include heavy metals, radioactive elements, pesticides, herbicides, fungicides, antibiotics and other chemical compounds that negatively affect the health of bees and the quality of beekeeping products. It is shown that the best indicators of the activity of the hygienic behavior of bees were noted for the territory with the least anthropogenic load and the most distant from the zone of hostilities (Vinnytsia region). The hygienic behavior of bees is that they identify and remove infected or dead larvae from the hive, which can be a source of disease and parasites. This behavior is an important factor in the survival of bee colonies and maintaining productivity. Further studies include the selection of bees and beekeeping products (honey, honey) for laboratory studies to assess the possibility of their use in bioindication of environmental pollution. Bioindication is a method of measuring the quality of the environment using living organisms that respond to changes in environmental conditions. Bees are sensitive bioindicators because they forage over a large area and reflect the level of contamination in their products. Analyzing the research results, it can be concluded that in one group of bees, the indicators of the time of complete removal of dead brood for 2022–2023 had an uneven character. Fairly low indicators of hygienic activity over the two-year period were noted in the 2nd and 3rd groups of bees, as the average value of the time of complete removal of dead larvae was 22.7 and 23.5 hours, respectively. The lowest indicators of the time of removal of dead brood over the entire period of observation were noted in the 5th group of bees. However, the average indicators of this group are 6.5% lower than in the control group. When studying the hygienic behavior of bee colonies, we found that the efficiency of removing dead brood depends on the strength of the colony. A correlation between the values of hygienic activity of bees and family strength obtained in 2022 was found in the 2nd (R=0.95) and 3rd (R=0.78) groups. In 2023, a strong relationship between the indicators of the time of removal of 100% of larvae and the strength of the family was noted in the 5th (R=0.74), 1st groups (R=0.72). This indicates that stronger bee colonies have a greater ability to self-cleanse from dangerous factors that may threaten their health and productivity.

Beyond the MEP Pathway: A novel kinase required for prenol utilization by malaria parasites.

A proposed treatment for malaria is a combination of fosmidomycin and clindamycin. Both compounds inhibit the methylerythritol 4-phosphate (MEP) pathway, the parasitic source of farnesyl and geranylgeranyl pyrophosphate (FPP and GGPP, respectively). Both FPP and GGPP are crucial for the biosynthesis of several essential metabolites such as ubiquinone and dolichol, as well as for protein prenylation. Dietary prenols, such as farnesol (FOH) and geranylgeraniol (GGOH), can rescue parasites from MEP inhibitors, suggesting the existence of a missing pathway for prenol salvage via phosphorylation. In this study, we identified a gene in the genome of P. falciparum, encoding a transmembrane prenol kinase (PolK) involved in the salvage of FOH and GGOH. The enzyme was expressed in Saccharomyces cerevisiae, and its FOH/GGOH kinase activities were experimentally validated. Furthermore, conditional knockout parasites (Δ-PolK) were created to investigate the biological importance of the FOH/GGOH salvage pathway. Δ-PolK parasites were viable but displayed increased susceptibility to fosmidomycin. Their sensitivity to MEP inhibitors could not be rescued by adding prenols. Additionally, Δ-PolK parasites lost their capability to utilize prenols for protein prenylation. Experiments using culture medium supplemented with whole/delipidated human plasma in transgenic parasites revealed that human plasma has components that can diminish the effectiveness of fosmidomycin. Mass spectrometry tests indicated that both bovine supplements used in culture and human plasma contain GGOH. These findings suggest that the FOH/GGOH salvage pathway might offer an alternate source of isoprenoids for malaria parasites when de novo biosynthesis is inhibited. This study also identifies a novel kind of enzyme related to isoprenoid metabolism.

Molecular detection of Trypanosoma lewisi in rodents distributed in dairy cattle pens and residential areas

The World Organisation for Animal Health continues to be concerned about the spread of atypical human-animal trypanosomiasis. Trypanosoma lewisi is one of the rodent-origin zoonotic trypanosomiasis. Despite the fact that many cases of T. lewisi in humans have been documented in several nations, the study of this pathogenic parasite in Indonesia remains limited. The objective of this investigation was to use a molecular approach to detect T. lewisi in rats captured in livestock pens and residential areas. In Pondok Ranggon Village, Cipayung District, East Jakarta, 14 traps were placed in dairy cattle pens and a total of 50 traps were installed outside and inside houses in Lhoksukon and Ceubrek Villages, Lhoksukon District, North Aceh. The captured rats were identified, sedated, and examined for ectoparasites. The blood of rats was then analysed using Giemsa-stained thin blood films and PCR with TRYP1R and TRYP1S primers. The majority of the Rattus species captured in three locations were R. tanezumi (62.07%), followed by R. norvegicus (6.90%) and R. exulans (3.4%). Xenopsylla cheopis were predominant insect found in the present study (60%), followed by Laelaps echidninus (20%), Laelaps nutalli (12%), and Ornithonyssus bacoti (8%). According to the total flea index, rats captured from cattle pens had fewer fleas than rats from other locations. The molecular analysis revealed that T. lewisi was present in 46.15% of rats captured in human settlements and 66.67% of rats captured in the dairy cattle pens. PCR result also demonstrated that positive T. lewisi found higher in inside house (66.67%) compared to outside house (28.57%). It indicates that trypanosome infections are prevalent in rats from domestic environments and cattle pens, and that R. tanezumi can potentially serve as a source of parasites for both animals and humans through fleas acting as vectors.

Actual Reasons Involving Turn-Off Losses Improvement With Increasing Load and Gate Resistance in MOSFETs Enhanced With Kelvin Source

This paper explains the actual reasons behind the improvement in terms of turn-off energy losses (Eoff) reduction, obtained using Kelvin pin (4-lead, 4L) MOSFETs instead of 3L ones. Eoff increases by increasing gate resistance and load, but the experimental results reveal that the increment is less in 4L than in 3L MOSFETs. Analysing the turn-off waveforms and adopting circuit analysis, the paper first proves that the common argument about the undesired effect of the parasitic source inductance in 3L MOSFETs is misleading. Then, the reasons behind the aforesaid improvement in 4L MOSFETs with increasing gate resistance and load are described by means of the derived analytical expressions. Finally, the analysis of the equations has provided helpful information at the design stage, also accounting for the different device technologies. In particular, the improvement obtained using 4L MOSFETs reduces as the driving loop parasitic inductance increases and evanesces if its value becomes comparable with the power loop parasitic inductance.

Nanoparticle tracking analysis of natural hemozoin from Plasmodium parasites

BackgroundHemozoin is a byproduct of hemoglobin digestion crucial for parasite survival. It forms crystals that can be of interest as drug targets or biomarkers of malaria infection. However, hemozoin has long been considered as an amorphous crystal of simple morphology. Studying the consequences of biomineralization of this crystal during the parasite growth may provide more comprehensive evidence of its role during malaria. ObjectivesThis study aimed to investigate the interest of nanoparticles tracker analysis for measuring the concentration and size of hemozoin particles produced from different parasite sources and conditions. MethodsHemozoin was extracted from several clones of Plasmodium falciparum both asexual and sexual parasites. Hemozoin was also extracted from blood samples of malaria patients and from saliva of asymptomatic malaria carriers. Nanoparticles tracking analysis (NTA) was performed to assess the size and concentration of hemozoin. ResultsNTA data showed variation in hemozoin concentration, size, and crystal clusters between parasite clones, species, and stages. Among parasite clones, hemozoin concentration ranged from 131 to 2663 particles/infected red blood cell (iRBC) and size ranged from 149.6 ± 6.3 nm to 234.8 ± 40.1 nm. The mean size was lower for Plasmodium vivax (176 ± 79.2 nm) than for Plasmodium falciparum (254.8 ± 74.0 nm). Sexual NF54 parasites showed a 7.5-fold higher concentration of hemozoin particles (28.7 particles/iRBC) compared to asexual parasites (3.8 particles/iRBC). In addition, the mean hemozoin size also increased by approximately 60 % for sexual parasites. Compared to in vitro cultures of parasites, blood samples showed low hemozoin concentrations. ConclusionsThis study highlights the potential of NTA as a useful method for analyzing hemozoin, demonstrating its ability to provide detailed information on hemozoin characterization. However, further research is needed to adapt the NTA for hemozoin analysis.

Deciphering Interactions between Potential Inhibitors and the Plasmodium falciparum DHODH Enzyme: A Computational Perspective.

Malaria is a parasitic disease that, in its most severe form, can even lead to death. Insect-resistant vectors, insufficiently effective vaccines, and drugs that cannot stop parasitic infestations are making the fight against the disease increasingly difficult. It is known that the enzyme dihydroorotate dehydrogenase (DHODH) is of paramount importance for the synthesis of pyrimidine from the Plasmodium precursor, that is, for its growth and reproduction. Therefore, its blockade can lead to disruption of the parasite's life cycle in the vertebrate host. In this scenario, PfDHODH inhibitors have been considered candidates for a new therapy to stop the parasitic energy source. Given what is known, in this work, we applied molecular fractionation with conjugated caps (MFCC) in the framework of the quantum formalism of density functional theory (DFT) to evaluate the energies of the interactions between the enzyme and the different triazolopyrimidines (DSM483, DMS557, and DSM1), including a complex carrying the mutation C276F. From these results, it was possible to identify the main features of each system, focusing on the wild-type and mutant PfDHODH and examining the major amino acid residues that are part of the four complexes. Our analysis provides new information that can be used to develop new drugs that could prove to be more effective alternatives to present antimalarial drugs.

Open-Source Magnetometer for Characterizing Magnetic Fields in Ultracold Experiments

We demonstrate a fully automated open-source magnetometer designed primarily for characterization of magnetic fields produced by coils, permanent magnets or by parasitic sources. It is based on an Arduino Mega microcontroller and a three-axis Hall sensor with a measurement range of ±8 G per axis and the RMS of the field readout below 0.3 mG. For all practical purposes, the sensor displacement during data acquisition is virtually unlimited, which can be particularly useful for characterizing large or extended coils like Helmholtz cages or Zeeman slowers. All components needed for the construction are cheap and widely available off-the-shelf elements or are 3D-printed. The operation of the magnetometer is controlled via a graphical user interface (GUI), which manages all essential functionalities, like data acquisition and plotting. The GUI also incorporates additional features, like data averaging, calibration of the displacement of the Hall sensor or real-time readout of the magnetic field, useful for monitoring magnetic field changes. We have used a pair of rectangular coils constructed for a potassium–cesium 2D magneto-optical trap to benchmark the performance of the magnetometer. We have obtained good agreement with both simulations and measurements acquired with a commercial gaussmeter.

Anthropophilic Small Mammals: Potential Source of Zoonotic Enteric Parasites in the Commune of Abobo, District of Abidjan (Côte d’Ivoire)

Objectives: This study aims to identify and assess intestinal parasites with zoonotic potential in terrestrial small mammals to better understand the associated risks. Methods: Live captures were performed using Sherman traps placed in human dwellings within the Abobo commune of Abidjan. Captured animals were euthanized and their legs were thoroughly washed with a Sodium Acetate Acetic Acid Formol solution. Subsequently, the digestive tract contents and leg washing fluids were examined using the Ritchie concentration method. Results: Mus musculus (75.3%) and Rattus rattus (13.5%) emerged as the most prevalent of small mammal species. Overall, 33.3% of these animals were infected with intestinal parasites. The predominant helminth species were Hymenolepis diminuta (8.9%) and Ancylostoma sp. (6.9%), while the primary pathogenic protozoa detected was Giardia intestinalis (2.3%). Conclusion: The presence of parasites of public health importance proves that cohabitation of small mammals with humans poses a significant risk to both public and veterinary health. These data therefore provide valuable information to local and provincial administrations, which should consider population control measures for small mammals to mitigate the transmission of zoonotic diseases to humans. They also provide information to medical practitioners for the diagnosis of possible zoonoses, and a reference for further studies in urban environments in Cote d'Ivoire.

Population structure and genetic connectivity of Plasmodium falciparum in pre-elimination settings of Southern Africa.

To accelerate malaria elimination in the Southern African region by 2030, it is essential to prevent cross-border malaria transmission. However, countries within the region are highly interconnected due to human migration that aids in the movement of the parasite across geographical borders. It is therefore important to better understand Plasmodium falciparum transmission dynamics in the region, and identify major parasite source and sink populations, as well as cross-border blocks of high parasite connectivity. We performed a meta-analysis using collated parasite allelic data generated by microsatellite genotyping of malaria parasites from Namibia, Eswatini, South Africa, and Mozambique (N = 5,314). The overall number of unique alleles was significantly higher (P ≤ 0.01) in Namibia (mean A = 17.3 ± 1.46) compared to South Africa (mean A = 12.2 ± 1.22) and Eswatini (mean A = 13.3 ± 1.27, P ≤ 0.05), whilst the level of heterozygosity was not significantly different between countries. The proportion of polyclonal infections was highest for Namibia (77%), and lowest for Mozambique (64%). A was significant population structure was detected between parasites from the four countries, and patterns of gene flow showed that Mozambique was the major source area and Eswatini the major sink area of parasites between the countries. This study showed strong signals of parasite population structure and genetic connectivity between malaria parasite populations across national borders. This calls for strengthening the harmonization of malaria control and elimination efforts between countries in the southern African region. This data also proves its potential utility as an additional surveillance tool for malaria surveillance on both a national and regional level for the identification of imported cases and/or outbreaks, as well as monitoring for the potential spread of anti-malarial drug resistance as countries work towards malaria elimination.

Molecular Detection of Toxoplasma gondii, Neospora caninum and Encephalitozoon spp. in Vespertilionid Bats from Central Europe.

Bats may carry various viruses and bacteria which can be harmful to humans, but little is known about their role as a parasitic source with zoonotic potential. The aim of this study was to test wild bats for the presence of selected parasites: Toxoplasma gondii, Neospora caninum and microsporidia Encephalitozoon spp. In total, brain and small intestine tissues of 100 bats (52 Myotis myotis, 43 Nyctalus noctula and 5 Vespertilio murinus) were used for the DNA isolation and PCR detection of the abovementioned agents. Toxoplasma gondii DNA was detected by real-time PCR in 1% of bats (in one male of M. myotis), while all bats were negative for N. caninum DNA. Encephalitozoon spp. DNA was detected by nested PCR in 25% of bats, including three species (twenty-two M. myotis, two N. noctula and one V. murinus). Positive samples were sequenced and showed homology with the genotypes Encephalitozoon cuniculi II and Encephalitozoon hellem 2C. This is the first study on wild vespertilionid bats from Central Europe and worldwide, with a relatively high positivity of Encephalitozoon spp. detected in bats.

Molecular Detection and Genetic Characterization of Zoonotic Hookworm in Semi-Domesticated Cats Residing in Monasteries in Bangkok, Thailand.

Hookworms are the most common parasitic nematodes in the genus of Ancylostoma that infect both humans and animals in subtropical and tropical South East Asia. The common hookworm species in cats is Ancylostoma ceylanicum which is emerging in Thailand. However, the genetic characterization of hookworms in cats is outdated and insufficiently studied in Thailand. We aimed to investigate the prevalence, risk factors and genetic characterization of hookworm infection in semi-domesticated temple cats in Bangkok, Thailand. A total of 500 temple cat fecal samples were collected from 43 monasteries in 24 districts of Bangkok, Thailand. Polymerase Chain Reaction (PCR) was performed by amplifying the internal transcribed spacer (ITS) gene and mitochondrial cytochrome oxidase c subunit I (cox 1) gene. The infection prevalence of hookworm in temple cats was 13.2% (66/500). The highest prevalence was 34.6% in the Bang Khun Thian district, which is located in a suburban area. The risk factor analysis revealed that cats older than one year (OR 2.4, 95% CI 1.1-5.5, p < 0.05), lack of veterinary attention (OR 2.9, 95% CI 1.7-4.9, p < 0.001) and Bangkok zone (suburban vs. inner city; OR 2.9, 95% CI 1.6-5.4, p < 0.001) were significantly increasing hookworm infection risk. All hookworm positive samples were identified as A. ceylanicum by ITS gene. Moreover, genetic characterization of cox 1 gene in A. ceylanicum isolates indicated a mix of isolates from humans, cats and dogs. The findings show that temple cats can act as a potential source of zoonotic hookworm parasites for the human and animal population in Bangkok, Thailand. Therefore, appropriate control measures for hookworms in semi-domesticated temple cats as well as prevention measures for hookworms in pet cats and humans should be promoted.

A diverse parasite pool can improve effectiveness of biological control constrained by genotype-by-genotype interactions.

The outcomes of biological control programs can be highly variable, with natural enemies often failing to establish or spread in pest populations. This variability has posed a major obstacle in use of the bacterial parasite Pasteuria penetrans for biological control of Meloidogyne species, economically devastating plant-parasitic nematodes for which there are limited management options. A leading hypothesis for this variability in control is that infection is successful only for specific combinations of bacterial and nematode genotypes. Under this hypothesis, failure of biological control results from the use of P. penetrans genotypes that cannot infect local Meloidogyne genotypes. We tested this hypothesis using isofemale lines of M. arenaria derived from a single field population and multiple sources of P. penetrans from the same and nearby fields. In strong support of the hypothesis, susceptibility to infection depended on the specific combination of host line and parasite source, with lines of M. arenaria varying substantially in which P. penetrans source could infect them. In light of this result, we tested whether using a diverse pool of P. penetrans could increase infection and thereby control. We found that increasing the diversity of the P. penetrans inoculum from one to eight sources more than doubled the fraction of M. arenaria individuals susceptible to infection and reduced variation in susceptibility across host lines. Together, our results highlight genotype-by-genotype specificity as an important cause of variation in biological control and call for the maintenance of genetic diversity in natural enemy populations.

Optimal design of kelvin source SiC MOSFET based PFC considering inductor parasitic capacitance and source mutual inductance

SiC MOSFET with Kelvin source has the advantage of high switching speed due to the lack of common source parasitic inductance. However, the high switching speed will make the parasitic parameters affect the performance of PFC converter obviously. Thus, it is necessary to analyze the influence of parasitic parameters on PFC circuits. The input PF model and switching energy loss model are established considering the inductor parasitic capacitance, and the influence of inductor parasitic capacitance on input PF and switching energy loss is analyzed. The switching energy loss model was established considering source mutual inductance, and the influence of source mutual inductance on switching energy loss was analyzed. Then we obtained the optimum value range of inductor parasitic capacitance and Kelvin source mutual inductance. The simulation and experimental results are given to verify the correctness of the mathematical model and analysis.