Toxoplasmosis in Piglets

Antibacterial and anti-Toxoplasma activities of Aspergillus niger endophytic fungus isolated from Ficus retusa: in vitro and in vivo approach

Emergent records propose that Aspergillus niger endophytic fungus is a vital source for various bioactive molecules possessing many biological properties. The current study was designed to inspect the antibacterial and anti-Toxoplasma potentials of Ficus retusa-derived endophytic fungi. After isolation and identification (using 18S rRNA gene sequencing) of A. niger endophytic fungus, LC/MS was utilized for identification and authentication of the chemical profile of the A. niger endophyte extract. Then, the fungal extract was assessed for its antibacterial and antibiofilm activities against Klebsiella pneumoniae clinical isolates. Additionally, its efficacy against Toxoplasma gondii was elucidated in vivo. The fungal extract displayed antibacterial activity against K. pneumoniae isolates with minimum inhibitory concentration values of 64-512 µg/mL. It also possessed a membrane potential dissipating effect using flow cytometry. Moreover, it formed distorted cells with rough surfaces and deformed shapes using a scanning electron microscope (SEM). Regarding its antibiofilm activity, it resulted in a dysregulation of the genes encoding biofilm formation (fimH, mrkA and mrkD) using qRT-PCR in nine K. pneumoniae isolates. The in vivo anti-Toxoplasma potential was demonstrated by decreasing the mortality rate of mice and reducing the tachyzoites' count in the peritoneal fluids and liver impression smears of mice. In addition, the deformities of the parasite decreased, as revealed by SEM and the inflammation in tissues diminished. Thus, A. niger endophytic fungi could be a valuable source of antibacterial and anti-Toxoplasma compounds.

Design and synthesis of novel bis-pyridinium based-ionic liquids as potent antiparasitic agents

Focused bis-pyridinium based-ionic liquids were successfully synthesized through the quaternization of the selected 1,2-di(pyridin-4-yl)ethane followed by metathetical anion exchange. The synthesized pyridinium derivatives were fully characterized using various NMR-spectroscopic techniques including ¹H, ¹³C, ¹¹B, ³¹P and ¹⁹F NMR. The synthesized compounds were tested for their potential effect against Toxoplasma gondii. It was revealed that compound 5 had higher antiparasitic activity compared to other compounds. Parasitic reduction percentage reached 38, 50, 77 and 79 for groups III, IV, V and VI respectively in the liver with noticed distortion and deformation in tachyzoites' shape. Surprisingly there was no statistically significant difference between the synthesized compound 5 and the known anti-toxoplasmosis drug pyrimethamine. Histopathological study proved the effectiveness of the synthesized compound 5 on liver, spleen and brain tissues with observed better histological features compared to pyrimethamine treated group. The present investigation may pave the way to the possible use of compound 5 to replace the known drug pyrimethamine with better antiparasitic profile and fewer side effects.

Decorative Multi-Walled Carbon Nanotubes by ZnO: Synthesis, Characterization, and Potent Anti-Toxoplasmosis Activity

Toxoplasmosis may become a fatal disease in immunodeficient, diabetic patients, pregnant women, and infants. Hence, the diligent search for new effective treatment is among the major concerns worldwide. The well-dispersed multi-walled carbon nanotubes lined with ZnO (ZnO-MWCNT), graphene oxide (GO-NPs), and zinc oxide (ZnO-NPs) were successfully synthesized through rapid and facile hydrothermal arc discharge technique (HTADT). The antiparasitic effects of ZnO-NPs, GO-NPs, and ZnO-MWCNT were investigated in mice infected with Toxoplasma gondii. The percent of tachyzoites reduction were detected. The observed results demonstrated that ZnO-MWCNT revealed a significant reduction in the parasite count reached 61% in brain tissues, followed by liver (52%), then spleen (45%). The assessments of antiparasitic, inflammatory, and anti-inflammatory cytokines confirmed the superior activity of ZnO-MWCNT as antiparasitic agent, which paves the way for the employment of ZnO-MWCNT as a treatment for the acute RH strain of T. gondii infection in vivo.

Exploring the Antiparasitic Activity of Tris-1,3,4-Thiadiazoles against Toxoplasma gondii-Infected Mice

Nitrogen-containing atoms in their core structures have been exclusive building blocks in drug discovery and development. One of the most significant and well-known heterocycles is the 1,3,4-thidiazole nucleus, which is found in a wide range of natural products and therapeutic agents. In the present work, certain tris-1,3,4-thiadiazole derivatives (6, 7) were synthesized through a multi-step synthesis approach. All synthesized compounds were characterized using different spectroscopic tools. Previously, thiadiazole compounds as anti-Toxoplasma gondii agents have been conducted and reported in vitro. However, this is the first study to test the anti-Toxoplasma gondii activity of manufactured molecular hybrids thiadiazole in an infected mouse model with the acute RH strain of T. gondii. All the observed results demonstrated compound (7)’s powerful activity, with a considerable reduction in the parasite count reaching 82.6% in brain tissues, followed by liver and spleen tissues (65.35 and 64.81%, respectively). Inflammatory and anti-inflammatory cytokines assessments proved that Compound 7 possesses potent antiparasitic effect. Furthermore, docking tests against TgCDPK1 and ROP18 kinase (two major enzymes involved in parasite invasion and egression) demonstrated compound 7’s higher potency compared to compound 6 and megazol. According to the mentioned results, tris-1,3,4-thiadiazole derivatives under test can be employed as potent antiparasitic agents against the acute RH strain of T. gondii.

Outbreak of toxoplasmosis associated with muscular lesions in finishing pigs caused by an atypical Toxoplasma gondii genotype

Toxoplasma gondii infections are usually asymptomatic in pigs, and an acute clinical disease is rare in this host. This study aimed to determine the pathological and molecular aspects of an outbreak of fatal systemic toxoplasmosis in finishing pigs in Brazil. The outbreak occurred on a commercial finishing pig farm in the state of Santa Catarina in southern Brazil. The farm had 1500 pigs and 3.8% of mortality rate during the outbreak. The pigs had fever, anorexia, apathy, and locomotor deficits. Seven pigs were necropsied. Gross findings included multifocal to coalescent pale areas in skeletal muscles, lymphadenomegaly, hepatosplenomegaly, and non-colapsed lungs. The histological findings included granulomatous lymphadenitis, hepatitis and splenitis, necrotizing myositis, and lymphoplasmacytic interstitial pneumonia. Lung and liver lesions were occasionally accompanied by T. gondii parasitic structures. Positive immunolabeling for T. gondii tachyzoites and encysted bradyzoites was detected in all examined pigs. PCR-RFLP (11 markers) and microsatellite analysis (15 markers) identified the non-archetypal genotype #278 in pigs. This is the first report of systemic toxoplasmosis in pigs with muscle lesions and additionally shows the diversity of disease-causing T. gondii genotypes circulating in animals in Brazil.

The global seroprevalence of Toxoplasma gondii in pigs: A systematic review and meta-analysis

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is an important disease with worldwide distribution. Infection can occur from ingesting raw or undercooked infected meat, and among food animal species, pork is known to be one of the main sources of meat-borne infection. Here, we present results of the first systematic review and meta-analysis on the global T. gondii seroprevalence in pigs. PubMed/MEDLINE, Scopus, and EMBASE databases were comprehensively searched for relevant studies published between January 1, 1990 and October 25, 2018. We used a random effects model to calculate pooled seroprevalence estimates with 95% confidence intervals (CI) and analyzed data from five continents. We also conducted subgroup and meta-regression analyses to evaluate the effects of geographical and climate variables on pooled seroprevalence rates. Among 1542 publications identified, 148 studies containing 150 datasets were included in the meta-analysis, and comprised 148,092 pigs from 47 countries. The pooled global T. gondii seroprevalence in pigs was estimated to be 19% (95%CI, 17-22%; 23,696/148,092), with the lowest seroprevalence in Europe (13%; 10-15%) and highest seroprevalence in Africa (25%; 17-34%) and North America (25%; 19-33%). The seropositivity rates in Asia and South America regions were (21%, 16-26%) and (23%; 17-30%), respectively. A significantly higher T. gondii seroprevalence was associated with higher mean annual temperature and lower geographical latitude. The presence of cats on farms was identified as a potential risk factor for T. gondii seropositivity (OR, 1.41; 95%CI, 1.00-2.02). Our findings highlight the importance of pigs as a possible source of human T. gondii infections.

Assessment of spiramycin-loaded chitosan nanoparticles treatment on acute and chronic toxoplasmosis in mice

Toxoplasmosis is a zoonotic parasitic disease with worldwide distribution. Chitosan is a natural polymer which is commonly used in the production of nanomedicines. It is known to enable higher drug permeation, being biocompatible and has very low toxicity, besides its antimicrobial effects. Our study aimed to assess the effect of spiramycin-loaded chitosan nanoparticles (SLCNs) in treatment of acute and chronic toxoplasmosis in mice. 200 male Swiss albino mice were included in our study, divided to two main groups; Toxoplasma gondii RH strain infected group and ME49 strain infected group, each main group was subdivided into four subgroups; subgroup I: infected control, subgroup II: infected and received chitosan nanoparticles (CS NPs); 20 µg of CS NPs in 100 µl of PBS/mouse/dose, subgroup III: infected and treated with spiramycin (Rovamycin); 100 mg/kg/day, subgroup IV: infected and treated with 100 mg/kg/day spiramycin-loaded chitosan nanoparticles. Effect of treatment was assessed parasitologically and histopathologically. It was noticed that SLCNs significantly decreased the mortality rate of infected mice with both strains compared to high mortality rate of mice in the infected control subgroups. Moreover, there was a significant decrease in the number of organisms of SLCNs treated subgroup as compared to the other subgroups. Histopathological studies showed a marked improvement of the pathological pictures of brain, liver, spleen and eye in the subgroup received SLCNs as opposed to other groups. In conclusion, the present study revealed that loading of spiramycin on chitosan nanoparticles increased its antiparasitic effect on acute and chronic T. gondii infection.

Toxoplasma gondii, a Foodborne Pathogen in the Swine Production Chain from a European Perspective

Toxoplasmosis is a foodborne zoonosis transmitted by Toxoplasma gondii, a cosmopolitan protozoan that infects humans through exposure to different parasite stages, in particular by ingestion of tissue cysts or tachyzoites contained in meat, primary offal (viscera), and meat-derived products or ingestion of environmental sporulated oocysts in contaminated food or water. The pig is an important species for infection: raw or undercooked pork consumption not subject to treatment able to inactivate the parasite represents a risk to consumers' health. Broadening knowledge of transmission ways and prevalence concerning this important pathogen in swine, together with a thorough acquaintance with hazard management are key elements to avoid T. gondii spreading within the swine production chain. This review aims to illustrate why toxoplasmosis should be regarded as a veterinary public health issue through a careful description of the parasite, routes of infection, and inactivation treatments, highlighting the main prevention lines from pig breeding to pork consumption.

The effect of chitosan nanospheres on the immunogenicity of Toxoplasma lysate vaccine in mice

Toxoplasmosis, a zoonotic parasitic disease, is a huge challenge for which there is no effective vaccine up till now. In this study, chitosan nanospheres encapsulated with Toxoplasma lysate vaccine was evaluated for its ability to protect mice against both acute and chronic toxoplasmosis models of infection. Results showed that chitosan nanospheres were equally effective to Freund's incomplete adjuvant (FIA) in enhancing the efficacy of Toxoplasma lysate vaccine. The effectiveness was demonstrated by the delayed death of vaccinated mice following challenge either with virulent RH or avirulent Me49 strains, the significant decrease in parasite density in different organs, significant increase in the humoral and cellular immune response (IgG and IFN γ) with a marked reduction of pathological changes in the different organs. However chitosan nanospheres were superior to FIA due to their cost effective preparation and much less necrotic changes induced in the studied organs. The success of chitosan polymer as an alternative to commonly used adjuvants paves the way for the use of other newly developed polymers to be used in the field of vaccine development.

Lower expression of inducible nitric oxide synthase and higher expression of arginase in rat alveolar macrophages are linked to their susceptibility to Toxoplasma gondii infection

Rats are naturally resistant to Toxoplasma gondii infection, particularly the RH strain, while mice are not. Previous studies have demonstrated that inducible nitric oxide synthase (iNOS) and arginase-1 of rodent peritoneal macrophages are linked to the mechanism of resistance. As an increasing number of studies on human and animal infections are showing that pulmonary toxoplasmosis is one of the most severe clinical signs from T. gondii infection, we are interested to know whether T. gondii infection in alveolar macrophages of rats is also linked to the levels of iNOS and arginase-1 activity. Our results demonstrate that T. gondii could grow and proliferate in rat alveolar macrophages, both in vitro and in vivo, at levels higher than resistant rat peritoneal macrophages and at comparable levels to sensitive mouse peritoneal macrophages. Lower activity and expression levels of iNOS and higher activity and expression levels of arginase-1 in rat alveolar macrophages were found to be linked to the susceptibility of T. gondii infection in these cells. These novel findings could aid a better understanding of the pathogenesis of clinical pulmonary toxoplasmosis in humans and domestic animals.

Toxoplasmosis in rodents: ecological survey and first evidences in Thailand

Domestic and wild rodents known as the most abundant and diversified order of mammals have a key role in the ecological food chain and also in the transmission of parasites and pathogens to other animals. While foraging on the ground, they can get infected by Toxoplasma gondii, a protozoan parasite, which is the causative agent of toxoplasmosis. Therefore, they serve as intermediate hosts of T. gondii and can transmit it to their predators. To assess their role in the maintenance of T. gondii lifecycle in Thailand, we sampled rodents in a range of biotopes representative of the high biodiversity and conducted a serological survey with latex agglutination test to detect anti-T. gondii antibodies. Overall, 21 of 461 (4.6%) rodents had diagnostically significant antibody titers (cutoff, 1:64). Every species with at least 37 individuals captured tested positive, confirming the wide range of potential mammalian hosts of toxoplasmosis. None of the ecological traits (sex, maturity, morphology, season, or habitat) was found significant to predict the susceptibility to T. gondii both univariately and in a multivariate analysis. However, high prevalences were reported in either forested or anthropized areas. This survey constitutes the first confirmed serological investigation of T. gondii in rodents in Thailand. The rarity of both domestic and wild felids in Thailand emphasizes the importance of rodents in maintaining T. gondii, and questions the involvement of other carnivores in the life cycle.