Introduction Toxoplasma gondii is an intracellular parasite of importance to human and veterinary health. The structure and diversity of the genotype population of T. gondii varies considerably with ...respect to geography, but three lineages, type I, II and III, are distributed globally. Lineage III genotypes are the least well characterized in terms of biology, host immunity and virulence. Once a host is infected with T.gondii , innate immune mechanisms are engaged to reduce the parasite burden in tissues and create a pro-inflammatory environment in which the T H 1 response develops to ensure survival. This study investigated the early cellular immune response of Swiss-Webster mice post intraperitoneal infection with 10 tachyzoites of four distinct non-clonal genotypes of lineage III and a local isolate of ToxoDB#1. The virulence phenotype, cumulative mortality (CM) and allele profiles of ROP5, ROP16, ROP18 and GRA15 were published previously. Methods Parasite dissemination in different tissues was analyzed by real-time PCR and relative expression levels of IFNγ, IL12-p40, IL-10 and TBX21 in the cervical lymph nodes (CLN), brain and spleen were calculated using the ΔΔCt method. Stage conversion was determined by detection of the BAG1 transcript in the brain. Results Tissue dissemination depends on the virulence phenotype but not CM, while the TBX21 and cytokine levels and kinetics correlate better with CM than virulence phenotype. The earliest detection of BAG1 was seven days post infection. Only infection with the genotype of high CM (69.4%) was associated with high T-bet levels in the CLN 24 h and high systemic IFNγ expression which was sustained over the first week, while infection with genotypes of lower CM (38.8%, 10.7% and 6.8%) is characterized by down-regulation and/or low systemic levels of IFNγ. The response intensity, as assessed by cytokine levels, to the genotype of high CM wanes over time, while it increases gradually to genotypes of lower CM. Discussion The results point to the conclusion that the immune response is not correlated with the virulence phenotype and/or allele profile, but an early onset, intense pro-inflammatory response is characteristic of genotypes with high CM. Additionally, high IFNγ level in the brain may hamper stage conversion.
Background. The constant growth of the global population has led to increasing food production, which has been particularly evident in the production of pork in recent years. In 2015, the number of ...pigs surpassed one billion, and in 2018 a record high of 120 million tonnes of pork was produced worldwide. In spite of the expansion and dominance of specialized industrial farming in developed countries, Toxoplasma gondii infection in pigs as a source of human infection remains an issue in traditional small-scale farming. The disease burden of toxoplasmosis is estimated to be the highest of all parasitic infections and even higher than that of salmonellosis and campylobacteriosis. Scope and Approach. This paper reviews the latest research on T. gondii-contaminated pork and pork products, published in the past decade. As current methods do not allow for practical and cost-effective detection of T. gondii at slaughter, efforts towards safe meat have focused on the detection of the parasite in pork and ready-to-eat pork products and on post-harvest mitigation measures. Key Findings and Conclusions. In contrast to recommendations for preventing Trichinella infection, there are no globally applicable standardised and validated inactivation procedures for rendering T. gondii infected pork/pork products safe for consumers. Moreover, there are no EU regulations in place for the prevention of T. gondii infection by consumption of pork and pork products. Recommended actions, both at the producer and consumer levels, include post-harvest processing such as cooking, freezing, and proper salting/curing.
A substantial proportion of echinococcosis transmission to humans via contamination of food has been assumed. However, the relative importance of food as a transmission vehicle has previously been ...estimated through expert opinion rather than empirical data.
To find and evaluate empirical data that could be used to estimate the source attribution of echinococcosis, in particular the proportion that is transmitted through contaminated food.
A systematic review was undertaken to identify reports on the risk factors for human cystic (CE) and alveolar (AE) echinococcosis. Data bases searched included PubMed, Scopus, Web of Knowledge, Cab Direct, Science Direct, Google Scholar, eLIBRARY.RU, CyberLeninka, CNKI and VIP. Search terms included Echinococc*, hydatid, epidemiology, logistic regression, risk factors, odds ratio, relative risk, risk factors. Reports, including grey literature where available, that had suitable data were selected and data were extracted. The main pathways of transmission were hypothesised to be contact with the definitive host, contaminated water, contaminated food and contaminated environment (other than food). For each study the attributable fraction for these potential sources of infection was calculated from the data presented. A meta-analysis was then undertaken to obtain pooled estimates for the relative contribution of these transmission pathways.
Data from 28 cross-sectional studies and 14 case-control studies were extracted. There was strong evidence for transmission by direct contact with dogs for both CE and AE. The estimated attributable fractions were 26.1% (CI 13.8%-39.6%) and 34.4% (CI 20.7% -48.2%) respectively. Transmission through contaminated water was estimated to be responsible for approximately 29.4% (CI 12.1%-51.7%) for CE and 24.8% (CI 10.6% to 42.6%) for AE. Contaminated food may be responsible for approximately 23.4% of CE cases (CI 2.1%-47.3%). Globally, there was insufficient evidence to conclude AE can be transmitted by food, although case control studies from low human incidence areas suggested that possibly 32.5% (CI 10.0%-53.2%) could be transmitted by food. There was also insufficient evidence that direct contact with foxes was a significant source of human disease. There were no suitable studies with a risk of environmental contact reported, but the residual attributable fraction thatwould likely include this pathway was approximately 21.1% for CE and 11.1% for AE.
The results support the hypothesis that dog contact and drinking contaminated water are major pathways of transmission of both CE and AE. For contaminated food, the results are less consistent, but suggest that it is an important transmission pathway and provide better evidence than expert elicitations as previously used.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Toxoplasma gondii is an obligate intracellular parasite infecting up to one third of the human population. The central event in the pathogenesis of toxoplasmosis is the conversion of tachyzoites into ...encysted bradyzoites. A novel approach to analyze the structure of in vivo-derived tissue cysts may be the increasingly used computational image analysis. The objective of this study was to quantify the geometrical complexity of T. gondii cysts by morphological, particle, and fractal analysis, as well as to determine if it is impacted by parasite strain, cyst age, and host type. A total of 31 images of T. gondii brain cysts of four type-2 strains (Me49, and local isolates BGD1, BGD14, and BGD26) was analyzed using ImageJ software. The parameters of interest included diameter, circularity, packing density (PD), fractal dimension (FD), and lacunarity. Although cyst diameter varied widely, its negative correlation with PD was observed. Circularity was remarkably close to 1, indicating a perfectly round shape of the cysts. PD and FD did not vary among cysts of different strains, age, and derived from mice of different genetic background. Conversely, lacunarity, which is a measure of heterogeneity, was significantly lower for BGD1 strain vs. all other strains, and higher for Me49 vs. BGD14 and BGD26, but did not differ among Me49 cysts of different age, or those derived from genetically different mice. The results indicate a highly uniform structure and occupancy of the different T. gondii tissue cysts. This study furthers the use of image analysis in describing the structural complexity of T. gondii cyst morphology, and presents the first application of fractal analysis for this purpose. The presented results show that use of a freely available software is a cost-effective approach to advance automated image scoring for T. gondii cysts.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
As pork is an important source for
infection, we have analyzed
genotypes and toxoplasmosis prevalence in pigs in Serbia in the context of production statistics and economics to assess the specific ...risk to public health. Genotyping was performed using MnPCR-RFLP;
-specific IgG antibodies were detected using a modified agglutination test (MAT); and statistical data were extracted from official records and provided by government authorities. The results indicate that, from 2006 to 2021, the median number of annually slaughtered pigs was 5.6 million, yet only 36.1% were processed by abattoirs. The remainder were "backyard pigs" slaughtered on family farms and homesteads. Toxoplasmosis seroprevalence in market-weight (MW) pigs prior to 2006 was 15.2%, and was 15.1% in 2019. The seroprevalence in owned city cats, likely infected by livestock meat, was 33.2%. ToxoDB#1 was identified in pig tissues. The results indicate that backyard pigs are the backbone of the industry and provide as much as 60% of the pork in Serbia. The seroprevalence in pigs and city cats shows that farms are reservoirs for the parasite. Thus, innovative means of reducing
infection designed with backyard farmers in mind are needed to reduce the risk to public health.
Real-life data on the performance of vaccines against SARS-CoV-2 are still limited. We here present the rates of detection and levels of antibodies specific for the SARS-CoV-2 spike protein RBD ...(receptor binding domain) elicited by four vaccines available in Serbia, including BNT-162b2 (BioNTech/Pfizer), BBIBP-CorV (Sinopharm), Gam-COVID-Vac (Gamaleya Research Institute) and ChAdOx1-S (AstraZeneca), compared with those after documented COVID-19, at 6 weeks and 3 months post first vaccine dose or post-infection. Six weeks post first vaccine dose, specific IgG antibodies were detected in 100% of individuals fully vaccinated with BNT-162b2 (
= 100) and Gam-COVID-Vac (
= 12) and in 81.7% of BBIBP-CorV recipients (
= 148), while one dose of ChAdOx1-S (
= 24) induced specific antibodies in 75%. Antibody levels elicited by BNT-162b2 were higher, while those elicited by BBIBP-CorV were lower, than after SARS-CoV-2 infection. By 3 months post-vaccination, antibody levels decreased but remained ≥20-fold above the cut-off in BNT-162b2 but not in BBIBP-CorV recipients, when an additional 30% were seronegative. For all vaccines, antibody levels were higher in individuals with past COVID-19 than in naïve individuals. A total of twelve new infections occurred within the first 3 months post-vaccination, eight after the first dose of BNT-162b2 and ChAdOx1-S (one each) and BBIBP-CorV (six), and four after full vaccination with BBIBP-CorV, but none required hospitalization.
Toxoplasma gondii
is a widespread zoonotic protozoan that infects most species of mammals and birds, including poultry. This study aimed to investigate the course of
T
.
gondii
infection and the ...efficacy of diclazuril and
Artemisia annua
in preventing infection in experimentally infected chickens. Seventy-five 1-month-old chickens, female and male, were randomly divided into five groups (
n
= 15 each) as follows: (1) uninfected untreated (negative control, NC); (2) infected with
T
.
gondii
genotype II/III isolated from a wild cat (group WC); (3) infected with
T
.
gondii
genotype II isolated from a domestic cat (group DC); (4) infected with
T
.
gondii
domestic cat strain and treated with the anticoccidial diclazuril (group DC-D); and (5) infected with
T
.
gondii
domestic cat strain and treated with the medicinal plant
Artemisia annua
(group DC-A). Clinical signs, body temperature, mortality rate, weight gain, feed conversion ratio, hematological parameters, and the presence of
T
.
gondii
–specific IgY antibodies were recorded in all groups. Five chickens per group were euthanized 28 days post-infection (p.i.) and their brains, hearts, and breast muscle tested for
T
.
gondii
by mouse bioassay and polymerase chain reaction (PCR). No clinical signs related to the experimental infection were observed throughout the study period
. T
.
gondii
–specific antibodies were detected by day 28 p.i., but not in all infected chickens. Overall,
T
.
gondii
DNA was detected (bioassay or tissue digests) in all infected and untreated chickens (10/10), while viable parasite (bioassay) was isolated from 7 out of 10 chickens. The parasite was most frequently identified in the brain (7/10). There were no differences in the
T. gondii
strains regarding clinical infection and the rate of
T
.
gondii
detection in tissues. However, higher antibody titers were obtained in chickens infected with
T
.
gondii
WC strain (1:192) comparing with
T
.
gondii
DC strain (1:48).
A
.
annua
reduced replication of the parasite in 3 out of 5 chickens, while diclazuril did not. In conclusion, broiler chickens were resistant to clinical toxoplasmosis, irrespective of the strain (domestic or wild cat strain). The herb
A
.
annua
presented prophylactic efficacy by reduced parasite replication. However, further studies are required aiming at the efficacy of diclazuril and
A
.
annua
for the prevention of
T
.
gondii
infection in chickens using quantitative analysis methods.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Toxoplasma gondii archetypes II and III are mildly virulent, yet virulence of variant strains is largely unknown. While lineage II dominates in humans in Europe, lineage III strains are present in ...various intermediate hosts. In Serbia, lineage III represents 24% of the population structure and occurs most frequently in domestic animals, implying a significant presence in the human food web. In this study, the virulence of four genetically distinct lineage III variants was assessed in vivo and in vitro. In vivo, two strains were shown to be intermediately virulent and two mildly virulent, with cumulative mortalities of 69.4%, 38.8%, 10.7%, and 6.8%, respectively. The strain with the highest mortality has previously been isolated in Europe and may be endemic; the strain with the lowest mortality matches ToxoDB#54, while the remaining two represent novel genotypes. Identical alleles were detected at ROP5, ROP16, ROP18, and GRA15. A set of in vitro analyses revealed proliferation and plaque formation as virulence factors. Higher levels of expression of ENO2 in intermediately virulent strains point to enhanced metabolism as the underlying mechanism. The results suggest that metabolic attenuation, and possibly stage conversion, may be delayed in virulent strains.
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•Serbia is traditionally endemic for both Taenia saginata and Taenia solium infection.•Between 1990 and 2018, the infection was continuously present through sporadic cases.•The annual ...number of cases was positively correlated with the consumer price index.•There is the potential for re-emergence in the case of socio-economic decline.
As is the case for all of Southeast Europe, Serbia is an area traditionally endemic for Taenia saginata and Taenia solium infections. This study was performed to analyse the epidemiological data on taeniosis and cysticercosis in Serbia for the period 1990–2018.
Data on cases of T. saginata and T. solium infection were collected via a systematic search of published articles, the grey literature, and official reports, as well as by performing clinical observational studies of patients treated in the departments for infectious diseases of hospitals and university clinics in Serbia.
A total of 212 cases of taeniosis were reported, all between 1997 and 2004 when taeniosis was notifiable (incidence range 0.04–0.9/100 000 population/year). From 1990 to 2018, 170 cases of cysticercosis (all but one of neurocysticercosis), were registered (incidence range 0–0.29/100 000 population/year), with a strong decrease since 2000 and a single case in the last 9 years. The annual number of cases of both taeniosis (Pearson’s r = 0.914, p = 0.001) and cysticercosis (Pearson’s r = 0.582, p = 0.014) correlated with the consumer price index.
In Serbia, T. saginata and T. solium infections are autochthonous but occur only sporadically. However, the potential for re-emergence exists, depending on the socio-economic state of the country.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Consumption of
contaminated pork is a major risk factor for human infection. We thus conducted a cross-sectional survey on the seroprevalence of
infection in a representative sample of slaughter pigs ...from throughout Serbia and examined the influence of farm biosecurity-related risk factors on infection. In addition, direct detection of the parasite (by mouse bioassay) or its DNA was performed in the hearts of a subset of seropositive sows. The overall seroprevalence in the sample of 825 pigs as determined by the modified agglutination test (MAT) was 16.5%. Older age and inadequate rodent control were independent infection risk factors for pigs. In a subset of 581 pigs with complete biosecurity-related data, in addition to older age, smallholders' finishing type farms (as opposed to farrow-to-finish), multispecies farming, and origin from Western and Central and South-Eastern Serbia (vs. the Northern region), all increased the risk of infection, while the absence of disinfection boot-dips in front of each barn and Belgrade district origin (vs. the Northern region) were associated with a 62% and 75% lower risk of infection, respectively. Evidence of viable parasites was obtained in 13 (41.9%) of the 31 bioassayed sow hearts, of which by isolation of brain cysts in seven, by detection of
DNA in an additional four, and by serology in another two. Recovery of brain cysts mostly (5/7) from sows with a MAT titre of ≥1:100 indicates the risk for consumers. These results highlight the public health risk from pork consumption and point to mandatory use of professional rodent control services, abstaining from multispecies farming, keeping disinfection boot-dips clean and freshly refilled, as well as strict implementation of zoo-hygienic measures on smallholders' farms as specific farm biosecurity measures needed for its reduction.
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