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The allelic combination of ROP18/ROP5 genes of Toxoplasma gondii has been shown to be highly predictive of mouse virulence in canonical isolates and strains. The aims of this study were to analyze the alleles present in the ROP18/ROP5 genes from T. gondii isolates obtained in Argentina, to associate the results with the virulence registered in mouse model, and to compare with other isolates and reference strains using a phylogenetic network. Fourteen T. gondii isolates from Argentina were analyzed by nPCR-RFLP for ROP18/ROP5. Phylogenetic network analysis was inferred using the ToxoDB genotypes and the ROPs molecular markers. All isolates and reference strains were categorized as lethal or non-lethal. As results, combinations 2/2, 3/3 and 4/3 for ROP18/ROP5 were detected in 12 isolates, whereas only alleles 1 and 2 of ROP5 were detected in 2 isolates. The majority of the isolates had a mouse virulence matching to that predicted by the ROP18/ROP5 allele combination. The 3 isolates that differed from the expected virulence presented non-clonal genotypes. ROPs incorporation increased the accuracy of the phylogenetic network relations among the T. gondii samples, prevailing the clustering according to regions. Our results indicate a predominance of type 3 allele in both ROP18 and ROP5 markers and an association of allelic profiles 3/3 and 4/3 of non-clonal genotypes from Argentina, both with virulent and avirulent profiles in mice. [Display omitted] • 14 T. gondii isolates from Argentina were analyzed by nPCR-RFLP for ROP18/ROP5. • Results showed a prevalence of type 3 allele in both markers. • Combinations 2/2, 3/3 and 4/3 for ROP18/ROP5 were detected. • Phylogenetic network clustered isolates by region. • ROP profiles 3/3, 4/3 of non-clonal genotypes could be related with mice virulence. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii and Neospora caninum infections may be associated with neuromuscular disorders in dogs. The aim of this study was to assess the seroprevalence to these protozoan parasites in dogs with neuromuscular disease from urban areas of Buenos Aires province, Argentina, over a period of 20 years, and to evaluate the association of seropositivity and antibody titres with different variables such as sex, breed and age. For this, a total of 7238 serum samples from urban owned dogs were analysed by the indirect fluorescence antibody test (IFAT) for specific IgG antibodies. The observed seropositivity rates were 35.7 % for T. gondii and 25.7 % for N. caninum. Crossbred dogs had a significantly higher seroprevalence for T. gondii than purebred dogs (41 % vs. 29.3 %), while a trend towards significance was observed for N. caninum, which was slightly higher in purebred dogs (26 % vs. 23.6 %). Seroprevalence for both parasites increased with age and was higher in older animals. Regarding the distribution of specific antibody titres, the most frequent IFAT T. gondii titre found was 100 and for N. caninum it was ≥800. For toxoplasmosis, there was no association with age group, and low titres (50, 100 and 200) predominated in all groups. However, for neosporosis, age and titres were significantly associated for one age group, with dogs under 12 months of age having a higher proportion of high titres (400 and 800). The trend in the seroprevalence for T. gondii is increasing over the years and lower antibody titres predominate in the dogs studied, which may be more related to the presence of chronic infections and not necessarily to the clinical signs of the animals. Despite the generally low titres observed for toxoplasmosis in this study, it is important to highlight the high seroprevalence found in our region, as dogs can act as sentinels of environmental contamination and as indicators of possible human infection. In the case of neosporosis, although the trend in seroprevalence in dogs with signs appears to be decreasing over the years, our work shows that higher antibody titres predominate, and are probably related to the clinical signs presented by the dogs. This study provides the most recent epidemiological data and serological profiles of T. gondii and N. caninum infections in a large number of canine sera from urban areas in Argentina, providing relevant information for clinical veterinarians and epidemiologists in order to understand the circulation of the parasites., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Venturini Maria Cecilia reports financial support was provided by UNLP, FONCyT. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Sarcocystis spp. are intracellular protozoan parasites with an obligatory heteroxenous life cycle. The objective of this study was to identify Sarcocystis spp. in pig muscles from Argentina, by light and transmission electron microscopy (TEM), and molecular studies. Muscles samples from 561 pigs (Sus scrofa domestica) were classified according to the breeding system in: intensive farming (IF, n = 295; animals kept in confinement during most of their productive cycle), or semi-extensive farming (SEF, n = 266; animals bred outdoors, generally family or backyard production). Results showed that 24.8% (139/561) were positive by light microscopy, with a significantly higher prevalence in the SEF (34.6%; 92/266) than the IF pigs (15.9%; 47/295) (p < 0.05). Of the 202 samples analyzed by PCR, 96 were positive (47.5%) for the 18S rRNA (18S ribosomal RNA) fragment. All samples analyzed by the S. suihominis specific coxI (mitochondrial cytochrome c oxidase subunit I) PCR (n = 235; 96 positives by 18S rRNA PCR and 139 positives by light microscopy) were negative. Fourteen individual cysts were positive for the 18S rRNA PCR and sequenced. Consensus sequences obtained from the 18S rRNA fragment PCR ranged from 613 to 880 bp and showed 100% of identity between them and with previously reported S. miescheriana sequences. In all the pig samples analyzed by TEM, cyst wall ultrastructure was compatible with S. miescheriana. This is the first study that provides infection rates and describes and identifies morphological and molecular features of Sarcocystis spp. cysts in pigs from Argentina., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

This study aimed to determine the nPCR-RFLP genotypes of newly obtained T. gondii isolates from human congenital toxoplasmosis cases in Argentina and to determine their allelic profiles for virulence genes ROP18/ROP5. In addition, the ROP18/ROP5 profiles were also determined for previously characterized T. gondii samples. Isolation from congenital toxoplasmosis cases was carried out in mouse bioassay from two placentas (P1 and P2). Genotyping for the new human isolates was performed by nPCR-RFLP using 10 markers. The samples analyzed for ROP18/ROP5 included the two newly obtained isolates (from the congenital toxoplasmosis cases) and nine previously genotyped T. gondii DNA samples from humans and chickens. The results for P1 and P2 named as TgHm18-02Arg and TgHm19-01Arg showed ToxoDB genotypes #14 (non-archetypal) and #2 (clonal type III), respectively. Non-archetypal #14 has been isolated from human cases before in Argentina. However, this is the first report of T. gondii clonal type III in a human case in the country. The ROP18/ROP5 combination was detected in nine samples: 3/3 (n = 1), 4/3 (n = 4), 4/4 (n = 3), and 3-4/4 (n = 1). Notably, the 4/4 profile was identified for the first time and exclusively in T. gondii samples from Misiones province (which borders southern Brazil). Further studies are required to corroborate the regionalization of the ROP18/ROP5 profiles in Argentina., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Toxoplasmosis is a worldwide parasitic zoonosis caused by Toxoplasma gondii. Pigs can become infected by consuming water or food contaminated with sporulated oocysts, or by carnivorism (like the consumption of infected rodents). In pigs most infections are asymptomatic. In certain countries, pig meat containing tissue cysts is a major source of infection for human beings. The aims of this study were to estimate the seroprevalence of toxoplasmosis and to identify which factors were related with the increase of the risk of infection in Argentina. The seroprevalence of T. gondii was determined in 240 pigs from 27 farms in the central-western area of Buenos Aires province, Argentina. Serum samples were analyzed using indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) techniques. Prevalence determined was 53.33% and 32.08% by IFAT and ELISA, respectively. Results showed that 81.5% (22/27) of the farms were seropositive to T. gondii. Seropositivity for T. gondii was related with the following risk factors (p value ≤0.05): presence of felids and rodents in the farms, feeding with waste of human food and storage of food outdoors with free access to felids and to the reservoirs when applying both serological techniques. Our results strongly suggest that the risk of infection with T. gondii in pigs is related to the outdoor/extensive type of production system with low infrastructure conditions, which allows both felids and rodents to have free access to pigs and stored food. Also, the high seroprevalence detected in the present study could indicate a potential role of pork in human infections in the region., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Toxoplasmosis, a worldwide distributed zoonosis, can be transmitted congenitally affecting fetuses and developing variable clinical signs. Different Toxoplasma gondii genotypes and infective dose are related factors with different clinical manifestations. Several studies indicate that atypical strains could produce more severe clinical manifestations compared to typical strains. Umbilical cord blood (n = 37) and placenta (n = 19) were collected at birth from women with acute T. gondii infection and processed for isolation by mice bioassay. Six isolates were obtained and identified as TgHm14-4Arg, TgHm15-02Arg, TgHm16-01Arg, TgHm16-02Arg, TgHm17-01Arg and TgHm17-02Arg. Three genotypes described previously on Toxo-DB were identified: #138 identified in chickens from Brazil, #182 isolated from eared doves from Brazil, #14 from wallaby kangaroos and chickens from Argentina, chickens from Brazil, Colombia, Chile and Venezuela, cats and dogs from Brazil and Colombia and also coyotes from USA indicating worldwide distribution of these genotypes. Two new allele combinations were obtained showing high genotypes diversity in Argentina. Four of the isolates (TgHm14-4Arg, TgHm15-02Arg, TgHm16-01Arg, TgHm16-02Arg) and two of them (TgHm17-01Arg, TgHm17-02Arg) produced chronic and acute infections in mice, respectively. Until now, seven T. gondii isolates have been obtained from humans in Argentina, and all were atypical or non-clonal genotypes. The identification of atypical strains causing congenital toxoplasmosis and circulating in our region, make important to perform the serological screenings according Argentine Consensus of Toxoplasmosis and to apply and monitoring treatments earlier in pregnancy. To achieve this aim, it is necessary to inform general population about T. gondii infection, diagnostics and control measures. These results should serve to generate awareness about congenital toxoplasmosis in South America., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Toxoplasma gondii and Neospora caninum are closely related coccidian parasites (phylum Apicomplexa). This is the first study from urban synanthropic rodent species that involved serological and molecular diagnosis of T. gondii and N. caninum infection, and genotyping of T. gondii in Argentina. A total of 127 rodent samples were trap captured: Mus musculus (n = 78), Rattus norvegicus (n = 26) and Rattus rattus (n = 23). Antibodies against T. gondii and N. caninum were detected by IFAT in 32.8% (40/122) and 0.8% (1/122) of rodent samples, respectively, demonstrating contact with these protozoans. Additionally, T. gondii DNA was detected in 3.3% (4/123) of rodent central nervous system samples and 2 samples were genotyped by multilocus nPCR-RFLP. Neospora caninum DNA was not detected by PCR. The 2 genotyped samples were type III allele for all markers except for SAG-1 (type I for Rat1Arg and type II/III for Rat2Arg) and were identified as #48 and #2 (likely) according to the allele combinations reported on Toxo DB (Toxo-DB). The results of the present study revealed a wide distribution of T. gondii and less for N. caninum, in synanthropic rats and mice in the studied area.

The protozoan Toxoplasma gondii is worldwide distributed showing a particular population structure that may differ among continents and countries. The aim of this study was to analyze the T. gondii population structure in Argentina and compare it with genotyping information from other South American countries. For the analysis, 39 samples from Argentina (isolates from the provinces of Buenos Aires, Misiones, Entre Ríos and San Luis) were genotyped using 10 multilocus PCR-RFLP markers including SAG1, SAG2 (5'-3'SAG2, alt. SAG2), SAG3, BTUB, GRA6, C22-8, C29-2, L358, PK1, and Apico. The T. gondii DNA samples were obtained from domestics animals (chickens n = 20; cats n = 3; pigs n = 2; goat n = 1; rabbit n = 1), humans (n = 6), zoo animals (n = 5) and a rat (n = 1). Phylogenetic relationship of these Argentinean isolates together with representative reference genotypes was determined by phylogenetic network analysis. Thirty-seven Argentinean samples belonged to 21 genotypes and two samples were genotyped at 8 of the 10 loci and considered incomplete characterized. Among these 37 typed samples, five genotypes were not previously reported. The majority of the samples grouped with the Type III (ToxoDB PCR-RFLP genotype #2) lineage. The clonal Type II (ToxoDB genotypes #1 and #3) was also identified. Our results suggest a unique population structure with combination of unique genotypes and the common Type II and Type III lineages in Argentina. Nevertheless, different regions showed distinctive pattern of genotypes, revealing a higher variability in Northern provinces., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Blood sample and placenta were taken from a 37-week pregnant woman; serologic results indicated acute toxoplasmosis. Placenta was inoculated into mice. Seropositive mice were sacrificed and tissue cysts from brain were inoculated into new mice. Specific DNA was detected by PCR, and the isolate was characterized as Type II by nPCR-RFLP for nSAG2, SAG3, BTUB, GRA6, c29-2, c22-8, L358, PK1 and Apico markers. This is the first isolation and molecular characterization of Toxoplasma gondii from humans in Argentina., (© 2013.)