Detection and genetic characterisation of Toxoplasma gondii circulating in free-range chickens, pigs and seropositive pregnant women in Benue state, Nigeria

Exploring the genetic diversity of Eimeria acervulina: A polymerase chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) approach

Eimeria, protozoan parasites that can cause the disease coccidiosis, pose a persistent challenge to poultry production and welfare. Control is commonly achieved using good husbandry supplemented with routine chemoprophylaxis and/or live parasite vaccination, although widespread drug resistance and challenges to vaccine supply or cost can prove limiting. Extensive effort has been applied to develop subunit anticoccidial vaccines as scalable, cost-effective alternatives, but translation to the field will require a robust understanding of parasite diversity. Using a new Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) panel we begin to describe the genetic diversity of Eimeria acervulina populations in Africa and Europe. PCR-RFLP genotyping E. acervulina populations sampled from commercial broiler and layer chickens reared in Nigeria or the United Kingdom (UK) and Republic of Ireland (RoI) revealed comparable levels of haplotype diversity, in direct contrast to previous descriptions from the close relative E. tenella. Here, 25 distinct PCR-RFLP haplotypes were detected from a panel of 42 E. acervulina samples, including 0.7 and 0.5 haplotypes per sample in Nigeria (n = 20) and the UK/RoI (n = 14), respectively. All but six haplotypes were found to be country-specific. The PCR-RFLP markers immune mapped protein 1 (IMP1) and heat shock protein 90 (HSP90) were most informative for Nigerian E. acervulina, while microneme protein 3 (MIC3) and HSP90 were most informative in UK/RoI populations. High haplotype diversity within E. acervulina populations may indicate frequent genetic exchange and potential for rapid dissemination of genetic material associated with escape from selective barriers such as anticoccidial drugs and future subunit vaccines.

Advances and Challenges in Diagnostics of Toxoplasmosis in HIV-Infected Patients

Toxoplasma gondii is a worldwide distributed protozoan parasite. This apicomplexan parasite infects one-third of the population worldwide, causing toxoplasmosis, considered one of the neglected parasitic infections. In healthy humans, most infections are asymptomatic. However, in immunocompromised patients, the course of the disease can be life-threatening. Human immunodeficiency virus (HIV)-infected patients have a very high burden of Toxoplasma gondii co-infection. Thus, it is essential to use modern, sensitive, and specific methods to properly monitor the course of toxoplasmosis in immunodeficient patients.

Molecular characterization and genotyping of Toxoplasma gondii in free-living animals in Iran: Effect of One Health

To understand the transmission of Toxoplasma gondii, this parasite's genetic diversity distribution in free-living hosts is essential. This research's objective is the molecular genotyping of T. gondii isolates from the brain and muscles of Columbidae, Corvidae, Rattus, and Felidae of Mianeh County, East-Azerbaijan Province, Northwest Iran. Three hundred fifty samples were taken. For the genotyping of T. gondii, the GRA6 gene was amplified and digested by the Tru1I (MseI) enzyme. Results of RFLP were confirmed by sequencing and phylogenetic analysis. In total, 52%, 34%, 24%, and 50% of Columbidae, Corvidae, Rattus, and Felidae were positive for T. gondii DNA, respectively. All isolated Columbidae were identified as genotype III (100%). Also, 94.1% and 5.9% of Corvidae isolates, 84.4% and 15.6% of the Rattus isolates, and 51.7% and 48.3% of the Felidae isolates belonged to genotypes III and II, respectively. This study is the first to evaluate genetic similarity and phylogenetic analysis between many definitive and intermediated hosts in northwestern Iran. The finding indicates that the T. gondii cycle is maintained among these hosts. As a result, their presence in the environment can be a risk factor for transmitting the infection to humans. Due to demographic and geographic differences in various regions, further studies are required to determine the genetic population structure.

Molecular Detection and Genotyping of Toxoplasma gondii from Pigs for Human Consumption in Zhejiang and Jiangsu Provinces, Eastern China

Toxoplasma gondii infections are common in humans and animals worldwide. Ingestion of raw or undercooked meat containing tissue cysts of T. gondii is one major source of transmission of this parasite. It is important to guarantee the meat quality of China since our pork industry produces about half of the world's pork. In this study, a total of 746 pig samples were collected from Zhejiang and Jiangsu provinces in eastern China, and examined for T. gondii infection by PCR amplification targeting B1 gene. In this study, we found that 57 of 746 (7.6%) pigs were positive for B1 gene, with 8.5% (48/562) in Zhejiang province and 4.9% (9/184) in Jiangsu province, respectively. The positive DNA samples were further genotyped at 11 genetic markers, including SAG1, 5'-and 3'-SAG2, alternative SAG2, SAG3, BTUB, GRA6, L358, PK1, c22-8, c29-2, and an apicoplast locus Apico through PCR-restriction fragment length polymorphism (PCR-RFLP) technology. Two genotypes (ToxoDB 9 and ToxoDB 10) of T. gondii were identified by PCR-RFLP in Zhejiang province. However, both genotypes were not determined from Jiangsu province, which is speculated on the low DNA concentration and the small number of samples. These results indicate that T. gondii infection is endemic in pigs in eastern China and may raise public food safety concerns, suggesting more interventions for T. gondii-related risks are needed in the future.

Can cloning and sequencing help to genotype positive Toxoplasma gondii clinical samples? Results and validation using SAG3 as a model

Genotyping of T. gondii in human cases is relevant to understand the transmission patterns and epidemiology of this parasitosis. However, this genetic characterization can be hampered by the difficulty of isolating the parasite from mild or asymptomatic cases and by the detection efficiency of molecular assays such as the multilocus nested-polymerase chain reaction-restriction fragment length polymorphism (Mn-PCR-RLFP). To propose an alternative for the genotyping of positive clinical samples of T. gondii with a low amount of the parasite DNA mixed within the host DNA or mixed infections, we carried out this study to validate the sequences of the SAG3 gene of T. gondii obtained after two rounds of amplification cloned into a bacterial model, thereby achieving the separation and identification of more than one genotype of T. gondii. Also, the detection limit of the parasite DNA and the fidelity of the reagents used in the nested PCR-RFLP in artificial clinical samples by sequencing were determined. T. gondii DNA was detected from 6.25 ng of DNA and 200 parasites/mL of blood. The fidelity of the AmpliTaq Gold™ polymerase after 65 cycles of amplification was 100%. Denaturation of the products obtained after two rounds of nested PCR amplification showed no evidence of chimera or artifact production. The cloning efficiency was 97.5% (39/40 clones), and none of the experiments produced recombinant sequences. Thus, the generation of chimeras with this methodology could be ruled out. Genotyping of clinical samples is important because there is no strain selection bias, as can occur in the bioassay (where more virulent strains can be selected over nonvirulent strains), and therefore, mixed infections can be detected through cloning and sequencing. Furthermore, these two techniques could be useful tools to genotype weak amplicons of any T. gondii gene obtained during nested PCR.

Neuroimmunology of Common Parasitic Infections in Africa

Parasitic infections of the central nervous system are an important cause of morbidity and mortality in Africa. The neurological, cognitive, and psychiatric sequelae of these infections result from a complex interplay between the parasites and the host inflammatory response. Here we review some of the diseases caused by selected parasitic organisms known to infect the nervous system including Plasmodium falciparum, Toxoplasma gondii, Trypanosoma brucei spp., and Taenia solium species. For each parasite, we describe the geographical distribution, prevalence, life cycle, and typical clinical symptoms of infection and pathogenesis. We pay particular attention to how the parasites infect the brain and the interaction between each organism and the host immune system. We describe how an understanding of these processes may guide optimal diagnostic and therapeutic strategies to treat these disorders. Finally, we highlight current gaps in our understanding of disease pathophysiology and call for increased interrogation of these often-neglected disorders of the nervous system.

Immunohistochemical detection and pathology of toxoplasmosis in Nigerian wild rats

Toxoplasmosis is a zoonotic disease of economic importance found worldwide, and it is caused by Toxoplasma gondii, which affects a wide range of hosts. High prevalence of toxoplasmosis has been reported in rodents, and they are considered very important in the circulation and maintenance of the disease. However, epidemiologic studies of the disease in rodents are generally scarce in the Tropics. This study utilized the immunohistochemical (IHC) technique to detect Toxoplasma gondii in wild rats sampled from across the North Central Nigeria. The brain, intestine, diaphragm, lungs and kidney tissue samples from 227 wild rats (Zyzomys pedunculatus) were routinely processed for histopathology, out of which 86 were further selected for IHC detection of T. gondii antigens using the streptavidin-peroxidase method. The histologic lesions observed were mild to moderate in severity, including meningitis, focal gliosis, neuronal degeneration and necrosis, villous atrophy and denudation, enteritis, diaphragmatic myositis, broncho-interstitial pneumonia and interstitial nephritis. Toxoplasma gondii was detected in 82.6% of the selected samples showing various degrees of immunoreaction intensity. We conclude that IHC is a useful tool in the detection of T. gondii in wild rats, and lungs and kidney may be the organ of choice for the detection of T. gondii.