ABSTRACT
Individual gene analyses of microtubule-based motor proteins in Dictyosteliumdiscoideum have provided a rough draft of its machinery for cytoplasmic organization and division. This review collates their activities and looks forward to what is next. A comprehensive approach that considers the collective actions of motors, how they balance rates and directions, and how they integrate with the actin cytoskeleton will be necessary for a complete understanding of cellular dynamics.
Subject(s)
Dictyostelium/metabolism , Microtubules/metabolism , Protozoan Infections/physiopathology , Cell Movement , Time FactorsABSTRACT
In biology, models are experimental systems meant to recreate aspects of diseases or human tissue with the goal of generating inferences and approximations that can contribute to the resolution of specific biological problems. Although there are many models for studying intracellular parasites, their data have produced critical contradictions, especially in immunological assays. Peripheral blood mononuclear cells (PBMCs) represent an attractive tissue source in pharmacogenomics and in molecular and immunologic studies, as these cells are easily collected from patients and can serve as sentinel tissue for monitoring physiological perturbations due to disease. However, these cells are a very sensitive model due to variables such as temperature, type of stimulus and time of collection as part of posterior processes. PBMCs have been used to study Toxoplasma gondii and other apicomplexan parasites. For instance, this model is frequently used in new therapies or vaccines that use peptides or recombinant proteins derived from the parasite. The immune response to T. gondii is highly variable, so it may be necessary to refine this cellular model. This mini review highlights the major approaches in which PBMCs are used as a model of study for T. gondii and other apicomplexan parasites. The variables related to this model have significant implications for data interpretation and conclusions related to host-parasite interaction.
Subject(s)
Apicomplexa/growth & development , Apicomplexa/immunology , Host-Pathogen Interactions , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/parasitology , Models, Theoretical , Protozoan Infections/physiopathology , Animals , Biomedical Research/trends , Humans , Protozoan Infections/immunology , Protozoan Infections/parasitologySubject(s)
Apicomplexa/physiology , Fungi/physiology , Host-Pathogen Interactions , Protozoan Infections/parasitology , Apicomplexa/genetics , Fungi/genetics , Plant Diseases/genetics , Plant Diseases/immunology , Plant Diseases/microbiology , Protozoan Infections/physiopathology , Protozoan Proteins/genetics , Protozoan Proteins/metabolismABSTRACT
Galectins is a family of multifunctional lectins. Fifteen galectins have been identified from a variety of cells and tissues of vertebrates and invertebrates. Galectins have been shown to play pivotal roles in host-pathogen interaction such as adhesion of pathogens to host cells and activation of host innate and adaptive immunity. In recent years, the roles of galectins during parasite infections have gained increasing attention. Galectins produced by different hosts can act as pattern recognition receptors detecting conserved pathogen-associated molecular patterns of parasites, while galectins produced by parasites can modulate host responses. This review summarizes some recent studies on the roles of galectins produced by parasitic protozoa, nematodes, and trematodes and their hosts. Understanding the roles of galectins in host-parasite interactions may provide targets for immune intervention and therapies of parasitic infections.
Subject(s)
Galectins/physiology , Host-Parasite Interactions/physiology , Immunity, Innate/physiology , Nematode Infections/physiopathology , Parasitic Diseases/physiopathology , Protozoan Infections/physiopathology , Trematode Infections/physiopathology , Animals , HumansSubject(s)
Apicomplexa/physiology , Apicomplexa/ultrastructure , Trypanosoma/physiology , Trypanosoma/ultrastructure , Animals , Cell Nucleus/physiology , Cell Nucleus/ultrastructure , Chromatin/physiology , Chromatin/ultrastructure , Humans , Nuclear Pore/physiology , Nuclear Pore/ultrastructure , Protozoan Infections/physiopathologyABSTRACT
BACKGROUND: As traditional lifestyle and diets change with social and economic development, disadvantaged communities in low- and middle-income countries increasingly face a double burden of communicable and non-communicable diseases. We studied the relationship between physical fitness and infections with soil-transmitted helminths (STHs), intestinal protozoa and Helicobacter pylori among schoolchildren in Port Elizabeth, South Africa. METHODS: We conducted a cross-sectional survey among 1009 children, aged 9 to 12 years, from eight primary schools in socioeconomically disadvantaged neighbourhoods of Port Elizabeth. Physical fitness was determined using field-deployable tests of the Eurofit fitness test battery. Stool samples were analysed with the Kato-Katz thick smear technique to diagnose STHs and with rapid diagnostic tests (RDTs) to detect intestinal protozoa and H. pylori infections. Haemoglobin (Hb) levels were assessed and anthropometric indicators determined. RESULTS: Complete data were available for 934 children (92 %). In two schools, high STH prevalences were found (Ascaris lumbricoides 60 and 72 %; Trichuris trichiura 65 % each). For boys and girls co-infected with A. lumbricoides and T. trichiura (n = 155) the maximal oxygen uptake (VO2 max) was estimated to be 50.1 and 47.2 ml kg(-1) min(-1), compared to 51.5 and 47.4 ml kg(-1) min(-1) for their non-infected peers (n = 278), respectively. On average, children without helminth infections had greater body mass (P = 0.011), height (P = 0.009) and a higher body mass index (P = 0.024) and were less often stunted (P = 0.006), but not significantly less wasted compared to their peers with a single or dual species infection. Among 9-year-old boys, a negative correlation between helminth infections and VO2 max, grip strength and standing broad jump distance was observed (P = 0.038). The overall mean Hb level was 122.2 g l(-1). In the two schools with the highest prevalence of STHs the Hb means were 119.7 and 120.5 g l(-1), respectively. CONCLUSIONS: Intestinal parasite infections appear to have a small but significant negative effect on the physical fitness of infected children, as expressed by their maximal oxygen uptake. We observed a clear impact on anthropometric indicators.
Subject(s)
Helicobacter Infections/physiopathology , Helminthiasis/physiopathology , Intestinal Diseases, Parasitic/physiopathology , Physical Fitness , Poverty Areas , Protozoan Infections/physiopathology , Body Height , Body Mass Index , Body Weight , Child , Coinfection/epidemiology , Coinfection/parasitology , Coinfection/physiopathology , Cross-Sectional Studies , Feces/parasitology , Female , Helicobacter Infections/complications , Helicobacter Infections/epidemiology , Helicobacter Infections/microbiology , Helicobacter pylori/isolation & purification , Helminthiasis/complications , Helminthiasis/epidemiology , Helminthiasis/parasitology , Humans , Intestinal Diseases, Parasitic/complications , Intestinal Diseases, Parasitic/epidemiology , Intestinal Diseases, Parasitic/parasitology , Male , Protozoan Infections/complications , Protozoan Infections/epidemiology , Protozoan Infections/parasitology , Soil/parasitology , South Africa/epidemiology , StudentsABSTRACT
OBJECTIVES: The aim of this study was to investigate whether protozoa can be identified as a cause of recurrent abdominal pain (RAP), and whether protozoan infections can be recognized by a specific clinical presentation. METHODS: For 2 years, all patients (ages 4-16 years) fulfilling the Apley criteria of RAP referred to secondary care were prospectively evaluated for protozoa (Giardia lamblia, Dientamoeba fragilis, Blastocystis hominis) and treated if positive. Re-examination followed at least 10 days after treatment. Disappearance of pain with eradication and a pain-free follow-up of at least 6 months were considered to be indicative of a causal relation with RAP. The predictive value of the characteristics of the pain for protozoan infections was calculated. RESULTS: Of 220 included patients (92 boys, mean age 8.8 years), 215 brought a stool sample; 73 (34%) carried parasites, 10 of whom had 2 parasites, 2 had 3 parasites. Sixty-five patients were treated. Twenty-five (11%) were pain-free after eradication (21 had D fragilis, 8 B hominis, 4 G lamblia), of whom 11 had another infection (2) or constipation (9) as second diagnosis for the pain. Five had recurrence of infection with D fragilis and were again pain-free with eradication. Patients with protozoa as cause of their pain did not show differences with respect to their presentation when compared with patients with an asymptomatic infection and patients without protozoa. CONCLUSIONS: Protozoa were found as the cause of pain in 6% to 11% of children with RAP. These patients did not show a characteristic presentation when compared with patients with other causes of abdominal pain.
Subject(s)
Abdominal Pain/etiology , Intestinal Diseases, Parasitic/physiopathology , Protozoan Infections/physiopathology , Abdominal Pain/epidemiology , Abdominal Pain/physiopathology , Abdominal Pain/prevention & control , Adolescent , Adult , Antiprotozoal Agents/therapeutic use , Blastocystis hominis/drug effects , Blastocystis hominis/isolation & purification , Causality , Child , Child, Preschool , Cohort Studies , Constipation/physiopathology , Dientamoeba/drug effects , Dientamoeba/isolation & purification , Female , Follow-Up Studies , Giardia lamblia/drug effects , Giardia lamblia/isolation & purification , Hospitals, Pediatric , Humans , Intestinal Diseases, Parasitic/drug therapy , Intestinal Diseases, Parasitic/parasitology , Male , Netherlands/epidemiology , Prospective Studies , Protozoan Infections/drug therapy , Protozoan Infections/parasitology , Referral and Consultation , Secondary Prevention , Severity of Illness Index , Young AdultSubject(s)
Humans , Parasitic Diseases/diagnosis , Parasitic Diseases/physiopathology , Parasitic Diseases/rehabilitation , Communicable Diseases/diagnosis , Communicable Diseases/physiopathology , Communicable Diseases/rehabilitation , Protozoan Infections/physiopathology , Protozoan Infections/microbiology , Protozoan Infections/parasitology , Bacteria/cytology , Bacteria/pathogenicity , Viruses/genetics , Viruses/immunology , Viruses/pathogenicityABSTRACT
UNLABELLED: Parasitic infections affect tens of millions of pregnant women worldwide. These infections lead directly and indirectly to a spectrum of adverse maternal and fetal/placental effects. With the increase in global travel, healthcare providers will care for women who have recently moved from or traveled to areas where these infections are endemic. We reviewed the literature, assessing case reports, case series, and prospective and retrospective trials, to provide guidelines for management of common parasitic infections in pregnancy. Parasitic infections tend to preferentially affect 1 part of the maternal-fetal unit. Thus, we categorize parasitic infections into those that preferentially cause harm to the mother, preferentially affect the fetus, and preferentially affect the placenta. TARGET AUDIENCE: Obstetricians and Gynecologists, Family Physicians, and Nurse Midwives. LEARNING OBJECTIVES: After completing this CME activity, physicians should be better able to differentiate immune modulators associated with parasitic infection and their relationship to adverse pregnancy outcomes; assess the specific effects of certain parasitic infections on the gravid female, her placenta, and her fetus; and in addition, design a treatment regimen for pregnant women presenting with a parasitic infection.
Subject(s)
Helminthiasis , Pregnancy Complications, Parasitic , Protozoan Infections , Antiparasitic Agents/therapeutic use , Female , Fetal Diseases/diagnosis , Fetal Diseases/drug therapy , Fetal Diseases/immunology , Fetal Diseases/physiopathology , Helminthiasis/diagnosis , Helminthiasis/drug therapy , Helminthiasis/physiopathology , Humans , Placenta Diseases/diagnosis , Placenta Diseases/drug therapy , Placenta Diseases/physiopathology , Pregnancy , Pregnancy Complications, Parasitic/diagnosis , Pregnancy Complications, Parasitic/drug therapy , Pregnancy Complications, Parasitic/immunology , Pregnancy Complications, Parasitic/physiopathology , Protozoan Infections/diagnosis , Protozoan Infections/drug therapy , Protozoan Infections/physiopathologyABSTRACT
After 30 years of the human immunodeficiency virus (HIV) epidemic, parasites have been one of the most common opportunistic infections (OIs) and one of the most frequent causes of morbidity and mortality associated with HIV-infected patients. Due to severe immunosuppression, enteric parasitic pathogens in general are emerging and are OIs capable of causing diarrhoeal disease associated with HIV. Of these, Cryptosporidium parvum and Isospora belli are the two most common intestinal protozoan parasites and pose a public health problem in acquired immunodeficiency syndrome (AIDS) patients. These are the only two enteric protozoan parasites that remain in the case definition of AIDS till today. Leishmaniasis, strongyloidiasis and toxoplasmosis are the three main opportunistic causes of systemic involvements reported in HIV-infected patients. Of these, toxoplasmosis is the most important parasitic infection associated with the central nervous system. Due to its complexity in nature, toxoplasmosis is the only parasitic disease capable of not only causing focal but also disseminated forms and it has been included in AIDS-defining illnesses (ADI) ever since. With the introduction of highly active anti-retroviral therapy (HAART), cryptosporidiosis, leishmaniasis, schistosomiasis, strongyloidiasis, and toxoplasmosis are among parasitic diseases reported in association with immune reconstitution inflammatory syndrome (IRIS). This review addresses various aspects of parasitic infections in term of clinical, diagnostic and therapeutic challenges associated with HIV-infection.
Subject(s)
AIDS-Related Opportunistic Infections/epidemiology , AIDS-Related Opportunistic Infections/parasitology , Antiretroviral Therapy, Highly Active/adverse effects , HIV Infections/complications , Immune Reconstitution Inflammatory Syndrome/pathology , Protozoan Infections/epidemiology , Protozoan Infections/physiopathology , AIDS-Related Opportunistic Infections/etiology , HIV Infections/drug therapy , Humans , Immune Reconstitution Inflammatory Syndrome/etiology , Protozoan Infections/diagnosis , Protozoan Infections/drug therapy , Protozoan Infections/parasitology , Seroepidemiologic StudiesABSTRACT
The aim of the study was to investigate if there is a possible relation between intestinal parasitosis and handedness in patients with suspected intestinal parasitosis. Hand preference was assessed on the Edinburgh Handedness Inventory. Stool samples were examined microscopically for the presence of parasite. In the present study right-handers had many more helminth infections and left-handers had many more protozoon infections. Lower rate of helminth infections in the present study, and higher asthma incidences in the left-handed population in literature, may be associated with different immune machinery in left-handed people than in right-handed ones.
Subject(s)
Functional Laterality/physiology , Adolescent , Adult , Female , Humans , Intestinal Diseases, Parasitic/immunology , Intestinal Diseases, Parasitic/physiopathology , Intestines/parasitology , Intestines/physiopathology , Male , Prevalence , Protozoan Infections/immunology , Protozoan Infections/physiopathology , Sex Factors , Surveys and Questionnaires , TurkeyABSTRACT
Programmed cell death is an essential mechanism of the host to combat infectious agents and to regulate immunity during infection. Consequently, activation and deactivation of the hosts' cell death pathways by protozoan parasites play critical roles in parasite control, pathogenesis, immune evasion and parasite dissemination within the host. Here, we discuss advances in the understanding of these fascinating host-parasite interactions with special emphasis on how protozoa can modulate the cell death apparatus of its host.
Subject(s)
Apoptosis/physiology , Host-Parasite Interactions/physiology , Protozoan Infections/pathology , Signal Transduction/physiology , Animals , Autophagy , Humans , Immunohistochemistry , Mammals , Protozoan Infections/parasitology , Protozoan Infections/physiopathology , Protozoan Proteins/physiologyABSTRACT
Oxidative stress has been implicated as an important pathogenic factor in the pathophysiology of various life-threatening diseases such as cancer, cardiovascular diseases and diabetes. It occurs when the production of free radicals (generated during aerobic metabolism, inflammation, and infections) overcome the antioxidant defences in the body. Although previous studies have implied that oxidative stress is present in serum of patients with parasitic infection there have been no studies confirming oxidative stress levels in the Malaysian population infected with intestinal parasites. Three biochemical assays namely hydrogen peroxide (H2O2), lipid peroxidation (LP) and advanced oxidative protein product (AOPP) assays were carried out to measure oxidative stress levels in the urine of human subjects whose stools were infected with parasites such as Blastocystis hominis, Ascaris, Trichuris, hookworm and microsporidia. The levels of H2O2, AOPP and LP were significantly higher (P<0.001, P<0.05 and P<0.05 respectively) in the parasite-infected subjects (n=75) compared to the controls (n=95). In conclusion, the study provides evidence that oxidative stress is elevated in humans infected by intestinal parasites. This study may influence future researchers to consider free radical-related pathways to be a target in the interventions of new drugs against parasitic infection and related diseases.
Subject(s)
Intestinal Diseases, Parasitic , Nematode Infections , Oxidative Stress , Protozoan Infections , Animals , Humans , Hydrogen Peroxide/urine , Intestinal Diseases, Parasitic/parasitology , Intestinal Diseases, Parasitic/physiopathology , Intestinal Diseases, Parasitic/urine , Lipid Peroxidation , Malondialdehyde/urine , Nematode Infections/parasitology , Nematode Infections/physiopathology , Nematode Infections/urine , Oxidation-Reduction , Proteins/metabolism , Protozoan Infections/parasitology , Protozoan Infections/physiopathology , Protozoan Infections/urineABSTRACT
BACKGROUND: Numerous protozoans inhibit the gastrointestinal tract of humans with the majority being either non-pathogenic commensals or of a type that may result in mild disease. However, some of these organisms can cause severe diseases under certain circumstances while others may become highly virulent and invasive causing potentially lethal systemic disease. This study investigated the prevalence, intensity and host morbidity of human intestinal protozoan infections in individuals living in the Buea Sub-Division, Cameroon. METHODOLOGY: Random sampling was used to collect stool samples from 356 patients in a cross-sectional study. All samples were examined by formol-ether concentration and direct smear techniques. Data collected was analyzed and differences in proportions were determined using the Chi square (chi(2)) test, Fisher's exact test, or analysis of variance where appropriate. RESULTS: It was found that 28.1% (100/356) of the sampled population were infected with protozoans. Females showed a higher infection rate (29.7%; 56/182) than males (26.4%; 46/174) and there was a significantly (P < 0.001) higher prevalence in rural areas (38.7%; 55/142) than in urban areas (21.0%; 45/214). The 6 to 12 years age group had a significantly (P < 0.05) higher infection rate (42.9%; 30/70). The total prevalence of intestinal protozoans was as follows: E. histolytica (24.4%), E. coli (11.2%) and G. lamblia (0.6%). The most prevalent morbidity effects associated with intestinal protozoan infections were abdominal pains, dysentery and body weakness. CONCLUSIONS: Since human intestinal parasitic infections are high in the study area, mass treatment of people with intestinal protozoans is strongly recommended, especially in the rural areas where the prevalence was very high.
Subject(s)
Gastrointestinal Diseases/etiology , Outpatients , Protozoan Infections/epidemiology , Protozoan Infections/parasitology , Abdominal Pain/etiology , Adolescent , Adult , Age Factors , Cameroon/epidemiology , Child , Child, Preschool , Cross-Sectional Studies , Dysentery/etiology , Entamoeba/isolation & purification , Feces/parasitology , Female , Gastrointestinal Diseases/physiopathology , Giardia lamblia/isolation & purification , Humans , Incidence , Infant , Male , Morbidity , Protozoan Infections/complications , Protozoan Infections/physiopathology , Rural Population , Sex Factors , Urban PopulationABSTRACT
Certain distinctive components of the severe systemic inflammatory syndrome are now well-recognized to be common to malaria, sepsis, viral infections, and post-trauma illness. While their connection with cytokines has been appreciated for some time, the constellation of changes that comprise the syndrome has simply been accepted as an empirical observation, with no theory to explain why they should coexist. New data on the effects of the main pro-inflammatory cytokines on the genetic control of sickness behaviour can be extended to provide a rationale for why this syndrome contains many of its accustomed components, such as reversible encephalopathy, gene silencing, dyserythropoiesis, seizures, coagulopathy, hypoalbuminaemia and hypertriglyceridaemia. It is thus proposed that the pattern of pathology that comprises much of the systemic inflammatory syndrome occurs when one of the usually advantageous roles of pro-inflammatory cytokines--generating sickness behaviour by moderately repressing genes (Dbp, Tef, Hlf, Per1, Per2 and Per3, and the nuclear receptor Rev-erbalpha) that control circadian rhythm--becomes excessive. Although reversible encephalopathy and gene silencing are severe events with potentially fatal consequences, they can be viewed as having survival advantages through lowering energy demand. In contrast, dyserythropoiesis, seizures, coagulopathy, hypoalbuminaemia and hypertriglyceridaemia may best be viewed as unfortunate consequences of extreme repression of these same genetic controls when the pro-inflammatory cytokines that cause sickness behaviour are produced excessively. As well as casting a new light on the previously unrationalized coexistence of these aspects of systemic inflammatory diseases, this concept is consistent with the case for a primary role for inflammatory cytokines in their pathogenesis across this range of diseases.
Subject(s)
Bacterial Infections/physiopathology , Cytokines/immunology , Protozoan Infections/physiopathology , Systemic Inflammatory Response Syndrome , Virus Diseases/physiopathology , Wounds and Injuries/physiopathology , Bacterial Infections/immunology , Humans , Protozoan Infections/immunology , Virus Diseases/immunology , Wounds and Injuries/immunologyABSTRACT
Intracellular pathogens such as viruses and bacteria subvert all the major cellular functions of their hosts. Targeted host processes include protein synthesis, membrane trafficking, modulation of gene expression, antigen presentation, and apoptosis. In recent years, it has become evident that protozoan pathogens, including members of the phylum Apicomplexa, also hijack their host cell's functions to access nutrients and to escape cellular defenses and immune responses. These obligate intracellular parasites provide superb illustrations of the subversion of host cell processes such as the recruitment and reorganization of host cell compartments without fusion around the parasitophorous vacuole of Toxoplasma gondii; the export of Plasmodium falciparum proteins on the surface of infected erythrocytes; and the induced transformation of the lymphocytes infected by Theileria parva, which leads to clonal extension.
Subject(s)
Apicomplexa/pathogenicity , Host-Pathogen Interactions/physiology , Animals , Apicomplexa/immunology , Apoptosis , Cryptosporidium parvum/pathogenicity , Host-Pathogen Interactions/immunology , Humans , Models, Biological , Organelles/parasitology , Plasmodium falciparum/pathogenicity , Protozoan Infections/parasitology , Protozoan Infections/pathology , Protozoan Infections/physiopathology , Theileria parva/pathogenicity , Toxoplasma/pathogenicityABSTRACT
The innate immune system is an evolutionally conserved host defense mechanism against pathogens. Innate immune responses are initiated by pattern recognition receptors (PRRs), which recognize microbial components that are essential for the survival of the microorganism. PRRs are germline-encoded, nonclonal, and expressed constitutively in the host. Different PRRs react with specific ligands and lead to distinct antipathogen responses. Among them, Toll-like receptors (TLRs) are capable of sensing organisms ranging from bacteria to fungi, protozoa, and viruses, and they play a major role in innate immunity. Here, we review the mechanism of pathogen recognition by TLRs.
Subject(s)
Toll-Like Receptors/drug effects , Toll-Like Receptors/physiology , Animals , Bacterial Infections/immunology , Bacterial Infections/physiopathology , Humans , Immunity, Innate/physiology , Ligands , Mycoses/immunology , Mycoses/physiopathology , Protozoan Infections/immunology , Protozoan Infections/physiopathology , Virus Diseases/immunology , Virus Diseases/physiopathologyABSTRACT
An experimental murine model of bovine genital tritrichomonosis is described. Female mice were inoculated per vaginam with Tritrichomonas foetus and a sample of the study population was killed every 3 days up to 60 days post-infection. Microscopical changes in the reproductive organs were assessed and immunohistochemistry was used to detect T. foetus within these tissues. Lectin histochemistry was used to determine changes in the expression of carbohydrates within the reproductive mucosa. A range of microscopical changes were detected in the uterine endometrium by 10 days post-inoculation and these were associated with the presence of the protozoan. The endometrial changes included endometritis and ulceration, mucosal atrophy and glandular metaplasia, and were similar to those reported in naturally infected cows. Changes in lectin binding were recognized first in the vagina where there was increased binding of Ulex europaeus agglutinin-1 (UEA-1) which was maximal on day 16 post-inoculation. Within the uterus, there was increased binding of soy bean agglutinin (SBA) which was maximal on day 19 post-inoculation, and of peanut agglutinin (PNA) which was maximal on day 16 post-inoculation. These changes in carbohydrate expression parallel the infection kinetics, since they appeared first in the vagina and later in the uterus. The changes may reflect either a host reaction against the infection or the production of enzymes by T. foetus, which act to enhance adhesion and colonization of the genital organs by the organism. The kinetics and pathogenesis of this murine infection are similar to those of the natural bovine disease, suggesting that this model system may be valuable for further studies of this disease.