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Current Opinion in Pharmacology Aug 2019Adenosine triphosphate (ATP) is released from host cells during parasite infections and acts as a danger signal in the extracellular space by activating plasma membrane... (Review)
Review
Adenosine triphosphate (ATP) is released from host cells during parasite infections and acts as a danger signal in the extracellular space by activating plasma membrane purinergic type 2 receptors-P2 receptors. The activation of these receptors has been described as a crucial step in immune cell activation, inflammation and parasite control. The P2X7 receptor is most involved in the activation of host microbicidal mechanisms, including production of reactive oxygen and nitrogen species, phagolysosomal fusion, acidification of parasitophorous vacuoles and release of cytokines and chemokines. The P2X7 receptor also modulates adaptive immune responses in various infectious diseases. Here, we discuss key points from the recent literature regarding P2X7 receptor activation during intracellular parasite infections.
Topics: Animals; Bacterial Infections; Humans; Immunomodulation; Protozoan Infections; Receptors, Purinergic P2X7; Virus Diseases
PubMed: 30901737
DOI: 10.1016/j.coph.2019.02.005 -
Parasitology Research Sep 2020Haemosporidia infections may cause major damage to avian populations and represent a concern for veterinarians working in zoological parks or wildlife rescue centres....
Haemosporidia infections may cause major damage to avian populations and represent a concern for veterinarians working in zoological parks or wildlife rescue centres. Following the fatal infection of 9 Great grey owls (Strix nebulosa) at Mulhouse zoological park, between summer 2013 and 2015, a prospective epidemiological investigation was performed in captive strigiform birds in France in 2016. The purpose was to evaluate the prevalence of haemosporidian parasites in captive Strigiformes and to estimate the infection dynamics around the nesting period. Blood samples were taken from 122 strigiform birds representing 14 species from 15 French zoological parks. Parasites were detected by direct examination of blood smears and by PCR targeting the mitochondrial cytochrome b gene. Haemosporidian parasites were detected in 59 birds from 11 zoos. Three distinct Haemoproteus mitochondrial cytochrome b sequences (haplotypes A and C for H. syrnii and haplotype B for Haemoproteus sp.) as well as two species of Plasmodium were detected. The overall prevalence of Haemoproteus infection was 12.8%. The percentage of birds infected by Haemoproteus varied according to the period of sampling. Nesting season seemed to be at greater risk with an average prevalence of 53.9% compared with winter season with an average prevalence of 14.8%, related to the abundance of the vectors. The prevalence of Plasmodium infection in Strigiformes did not exceed 8% throughout the year. This study confirmed how significant Haemosporidia infection could be in Strigiformes from zoological parks in France. The nesting season was identified as a period of higher risk of infection and consequently the appropriate period to apply prophylactic measures.
Topics: Animals; Bird Diseases; Cytochromes b; France; Haemosporida; Haplotypes; Phylogeny; Prospective Studies; Protozoan Infections, Animal; Protozoan Proteins; Strigiformes
PubMed: 32683557
DOI: 10.1007/s00436-020-06801-5 -
Current Opinion in Neurology Jun 2021Malaria, Chagas Disease and Human African Trypanosomiasis are vector-borne protozoan illnesses, frequently associated with neurological manifestations. Intriguing but... (Review)
Review
PURPOSE OF REVIEW
Malaria, Chagas Disease and Human African Trypanosomiasis are vector-borne protozoan illnesses, frequently associated with neurological manifestations. Intriguing but ignored, limited mainly to resource-limited, tropical settings, these disorders are now coming to light because of globalisation and improved diagnosis and treatment. Enhanced understanding of these illnesses has prompted this review.
RECENT FINDINGS
Methods of diagnosis have currently transitioned from blood smear examinations to immunological assays and molecular methods. Tools to assess neurological involvement, such as magnetic resonance imaging, are now increasingly available in regions and countries with high infection loads. Sleep and other electrophysiological technologies (electroencephalography, actigraphy) are also promising diagnostic tools but requiring field-validation. Access to treatments was formerly limited, even as limitations of agents used in the treatment are increasingly recognised. Newer agents are now being developed and trialled, encouraged by improved understanding of the disorders' molecular underpinnings.
SUMMARY
Prompt diagnosis and treatment are crucial in ensuring cure from the infections. Attention should also be due to the development of globally applicable treatment guidelines, the burden of neurological sequelae and elimination of the zoonoses from currently endemic regions.
Topics: Animals; Chagas Disease; Humans; Malaria, Cerebral; Trypanosomiasis, African
PubMed: 33709976
DOI: 10.1097/WCO.0000000000000919 -
International Journal For Parasitology Aug 2022Understanding the drivers of infection risk helps us to detect the most at-risk species in a community and identify species whose intrinsic characteristics could act as...
Understanding the drivers of infection risk helps us to detect the most at-risk species in a community and identify species whose intrinsic characteristics could act as potential reservoirs of pathogens. This knowledge is crucial if we are to predict the emergence and evolution of infectious diseases. To date, most studies have only focused on infections caused by a single parasite, leaving out co-infections. Yet, co-infections are of paramount importance in understanding the ecology and evolution of host-parasite interactions due to the wide range of effects they can have on host fitness and on the evolutionary trajectories of parasites. Here, we used a multinomial Bayesian phylogenetic modelling framework to explore the extent to which bird ecology and phylogeny impact the probability of being infected by one genus (hereafter single infection) or by multiple genera (hereafter co-infection) of haemosporidian parasites. We show that while nesting and migration behaviours influenced both the probability of being single- and co-infected, species position along the slow-fast life-history continuum and geographic range size were only pertinent in explaining variation in co-infection risk. We also found evidence for a phylogenetic conservatism regarding both single- and co-infections, indicating that phylogenetically related bird species tend to have similar infection patterns. This phylogenetic signal was four times stronger for co-infections than for single infections, suggesting that co-infections may act as a stronger selective pressure than single infections. Overall, our study underscores the combined influence of hosts' evolutionary history and attributes in determining infection risk in avian host communities. These results also suggest that co-infection risk might be under stronger deterministic control than single infection risk, potentially paving the way toward a better understanding of the emergence and evolution of infectious diseases.
Topics: Animals; Bayes Theorem; Bird Diseases; Birds; Coinfection; Communicable Diseases; Haemosporida; Parasites; Phylogeny; Plasmodium; Prevalence; Protozoan Infections, Animal
PubMed: 35760376
DOI: 10.1016/j.ijpara.2022.05.002 -
International Journal of Gynaecology... Oct 2023Trichomonas vaginalis infection is the most prevalent non-viral sexually transmitted infection (STI) in women and has been suggested as a risk factor for developing... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Trichomonas vaginalis infection is the most prevalent non-viral sexually transmitted infection (STI) in women and has been suggested as a risk factor for developing cervical cancer.
OBJECTIVE
We aimed to investigate the associations between T. vaginalis infection and cervical carcinogenesis.
SEARCH STRATEGY
A comprehensive systematic search was conducted in five databases on 21 October 2021.
SELECTION CRITERIA
Studies assessing the relationship between T. vaginalis infection, HPV co-infections, cervical dysplasia, and cervical cancer were found eligible.
DATA COLLECTION AND ANALYSIS
Summary estimates for pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated with a random-effects model. Statistical heterogeneity was measured with I and Cochran's Q tests.
MAIN RESULTS
The 29 articles included 473 740 women, of whom 8518 were T. vaginalis-positive. Our results showed that T. vaginalis-infected women had 1.79 times higher odds of being diagnosed with HPV co-infection (95% CI 1.27-2.53; I 95%). We also found that T. vaginalis infection was associated with high-grade squamous intraepithelial lesion diagnosis (OR 2.34, 95% CI 1.10-4.95; I 75%) and cervical cancer (OR 5.23, 95% CI 3.03-9.04; I 3%).
CONCLUSIONS
Our results showed an association between T. vaginalis and cervical carcinogenesis in sexually active women.
Topics: Humans; Female; Trichomonas vaginalis; Uterine Cervical Neoplasms; Papillomavirus Infections; Trichomonas Infections; Cervix Uteri; Trichomonas Vaginitis
PubMed: 37010897
DOI: 10.1002/ijgo.14763 -
PLoS Neglected Tropical Diseases Sep 2021Vector Borne Diseases (VBDs) are considered emerging and re-emerging diseases that represent a global burden. The aim of this study was to explore and characterize...
Vector Borne Diseases (VBDs) are considered emerging and re-emerging diseases that represent a global burden. The aim of this study was to explore and characterize vector-borne pathogens in different domestic animal hosts in Egypt. A total of 557 blood samples were collected from different animals using a convenience sampling strategy (203 dogs, 149 camels, 88 cattle, 26 buffaloes, 58 sheep and 33 goats). All samples were tested for multiple pathogens using quantitative PCR and standard PCR coupled with sequencing. We identified Theileria annulata and Babesia bigemina in cattle (15.9 and 1.1%, respectively), T. ovis in sheep and buffaloes (8.6 and 7.7%, respectively) and Ba. canis in dogs (0.5%) as well as Anaplasma marginale in cattle, sheep and camels (20.4, 3.4 and 0.7%, respectively) and Coxiella burnetii in sheep and goats (1.7 and 3%; respectively). New genotypes of An. centrale, An. ovis, An. platys-like and Borrelia theileri were found in cattle (1.1,3.4, 3.4 and 3.4%, respectively), An. platys-like in buffaloes (7.7%), An. marginale, An. ovis, An. platys-like and Bo. theileri in sheep (3.4, 1.7, 1.7 and 3.4%, respectively), An. platys, An. platys-like and Setaria digitata in camels (0.7, 5.4 and 0.7%, respectively) and Rickettsia africae-like, An. platys, Dirofilaria repens and Acanthocheilonema reconditum in dogs (1.5, 3.4, 1 and 0.5%, respectively). Co-infections were found in cattle, sheep and dogs (5.7, 1.7, 0.5%, respectively). For the first time, we have demonstrated the presence of several vector-borne zoonoses in the blood of domestic animals in Egypt. Dogs and ruminants seem to play a significant role in the epidemiological cycle of VBDs.
Topics: Animals; Animals, Domestic; Babesia; Bacteria; Bacterial Infections; Cross-Sectional Studies; Egypt; Filariasis; Filarioidea; Phyllachorales; Prevalence; Protozoan Infections, Animal; Vector Borne Diseases
PubMed: 34587171
DOI: 10.1371/journal.pntd.0009767 -
International Journal of Molecular... Feb 2020is gaining increasing attention as a model organism for the study of calcium binding and calmodulin function in basic biological events as well as human diseases. After... (Review)
Review
is gaining increasing attention as a model organism for the study of calcium binding and calmodulin function in basic biological events as well as human diseases. After a short overview of calcium-binding proteins, the structure of Dictyostelium calmodulin and the conformational changes effected by calcium ion binding to its four EF hands are compared to its human counterpart, emphasizing the highly conserved nature of this central regulatory protein. The calcium-dependent and -independent motifs involved in calmodulin binding to target proteins are discussed with examples of the diversity of calmodulin binding proteins that have been studied in this amoebozoan. The methods used to identify and characterize calmodulin binding proteins is covered followed by the ways is currently being used as a system to study several neurodegenerative diseases and how it could serve as a model for studying calmodulinopathies such as those associated with specific types of heart arrythmia. Because of its rapid developmental cycles, its genetic tractability, and a richly endowed stock center, is in a position to become a leader in the field of calmodulin research.
Topics: Binding Sites; Calcium; Calcium Signaling; Calmodulin; Calmodulin-Binding Proteins; Dictyostelium; EF Hand Motifs; Humans; Models, Molecular; Protein Binding; Protozoan Infections; Protozoan Proteins
PubMed: 32054133
DOI: 10.3390/ijms21041210 -
Research in Veterinary Science Mar 2021Toxoplasmosis is a zoonotic disease of global distribution and importance. It is caused by the protozoan parasite Toxoplasma gondii, the only species in the Toxoplasma... (Review)
Review
Toxoplasmosis is a zoonotic disease of global distribution and importance. It is caused by the protozoan parasite Toxoplasma gondii, the only species in the Toxoplasma genus. This parasite can infect most warm-blooded animals, including humans and livestock. Main routes of transmission are by ingestion of tissue cysts in raw or undercooked meat of infected animals, ingestion of raw vegetables or water contaminated with T. gondii oocysts from cat feces, and transplacental. Around one-third of human beings are chronically infected with T. gondii. Most infections appear to be asymptomatic in immunocompetent persons, but toxoplasmosis can be fatal to the fetus and immunocompromised adults. Water and foodborne outbreaks have been caused by this parasite worldwide, but few are well documented. Importantly, T. gondii is a parasite of high importance in animal health, causing reproductive failure, particularly in small ruminants, and clinical toxoplasmosis in many species. This overview discusses the knowledge of T. gondii infections in the last decade focusing on the foodborne transmission of this parasite.
Topics: Animals; Food Parasitology; Humans; Toxoplasma; Toxoplasmosis; Water; Zoonoses
PubMed: 33148402
DOI: 10.1016/j.rvsc.2020.10.019 -
Parasitology International Aug 2023Cytauxzoonosis is a life-threatening disease of cats, caused by the tick-borne piroplasmid hemoparasite, Cytauxzoon felis. Current experimental models for cytauxzoonosis...
BACKGROUND
Cytauxzoonosis is a life-threatening disease of cats, caused by the tick-borne piroplasmid hemoparasite, Cytauxzoon felis. Current experimental models for cytauxzoonosis rely on either tick transmission or direct injection of infected cat tissues. These models require researchers to directly work with infected ticks or use cats with acute cytauxzoonosis. To improve the feasibility and accessibility, there is a need to establish sharable resources among researchers. In related piroplasmid parasites, sporozoite-based inoculums are routinely produced from tick salivary glands, cryopreserved and distributed to other investigators and facilities. For these parasites, sporozoites have been the basis for vaccine development and in vitro cultivation, both of which remain lacking for C. felis research. If infectious sporozoites can be similarly isolated for C. felis, it would significantly broaden our capabilities to study this parasite. Aims of this study was to determine if C. felis sporozoites inoculums collected from the salivary glands of Amblyomma americanum ticks were capable of inducing cytauxzoonosis in naïve cats.
MATERIALS AND METHODS
A. americanum nymphs were acquisition-fed on a donor cat chronically infected with C. felis and allowed to molt to adults. Four groups of adult ticks (n = 50/group) were either stimulation-fed for 4 days on naïve cats or were heated at 37 °C for 4 days. After these treatments, salivary glands (SG) of each group of ticks were collected to create inoculums. Infectivity of these inoculums was then tested by subcutaneous injection into naïve cats.
RESULTS
The two naïve cats used for stimulation feeding and as controls both developed cytauxzoonosis, indicating these groups of ticks were capable of producing infectious sporozoites. Of the 2 cats that were injected with SGs from the stimulation-fed ticks, one cat developed cytauxzoonosis and C. felis infection was confirmed by both light microscopy and PCR. The other cat did not develop cytauxzoonosis and only had equivocal evidence of infection. Neither cat injected with SGs from the heated ticks developed cytauxzoonosis. One of these cats had equivocal evidence of infection and one had no evidence of infection.
CONCLUSION
This study validates the feasibility of collecting infectious sporozoites from C. felis-infected ticks that can be used to infect naïve cats. While this model requires further optimization, it has the potential to expand resources to study C. felis and further advance research in this field.
Topics: Animals; Cats; Amblyomma; Ixodidae; Protozoan Infections, Animal; Ticks; Piroplasmida; Felis; Cat Diseases
PubMed: 37086887
DOI: 10.1016/j.parint.2023.102753 -
PLoS Pathogens Sep 2021
Topics: Animals; Anthozoa; Apicomplexa; Coral Reefs; Protozoan Infections
PubMed: 34529733
DOI: 10.1371/journal.ppat.1009845