КРИПТОСПОРИДИОЗ ЖИВОТНЫХ КАК ЗООНОЗ, КЛИНИЧЕСКИЕ И ЭПИЗООТОЛОГИЧЕСКИЕ АСПЕКТЫ

The Japanese Society of Fish Pathology held a symposium entitled “Current topics on protozoan and other parasitic diseases of fish in Japan” in Miyazaki on 27th September 2001. This symposium was aimed to have an overview of the current status of the researches on protozoan and other parasitic diseases of fish in Japan. Following a keynote presentation of the same subject in the world, two emerging diseases of marine fish in Japan, i.e. emaciation disease in tiger puffer and anemia in Japanese flounder, were introduced. Three species of myxosporeans are responsible for the former disease, and a monogenean Neoheterobothrium hirame causes the latter. The resent researches on kudoosis amami in yellowtail and amberjack, Heterobothrium infection in tiger puffer and blood fluke disease in yellowtail were also presented. The importance of the prevention against the fish protozoan and other parasitic diseases was discussed.

Protozoan parasitic diseases are endemic in many countries worldwide, especially in developing countries, where infertility is a major burden. It has been reported that such infections may cause infertility through impairment in male and female reproductive systems. We searched Medline, PubMed, and Scopus databases and Google scholar to identify the potentially relevant studies on protozoan parasitic infections and their implications in human and animal model infertility. Literature described that some of the protozoan parasites such as Trichomonas vaginalis may cause deformities of the genital tract, cervical neoplasia, and tubal and atypical pelvic inflammations in women and also non-gonoccocal urethritis, asthenozoospermia, and teratozoospermia in men. Toxopalasma gondii could cause endometritis, impaired folliculogenesis, ovarian and uterine atrophy, adrenal hypertrophy, vasculitis, and cessation of estrus cycling in female and also decrease in semen quality, concentration, and motility in male. Trypanosoma cruzi inhibits cell division in embryos and impairs normal implantation and development of placenta. Decrease in gestation rate, infection of hormone-producing glands, parasite invasion of the placenta, and overproduction of inflammatory cytokines in the oviducts and uterine horns are other possible mechanisms induced by Trypanosoma cruzi to infertility. Plasmodium spp. and Trypanosoma brucei spp. cause damage in pituitary gland, hormonal disorders, and decreased semen quality. Entamoeba histolytica infection leads to pelvic pain, salpingitis, tubo-ovarian abscess, and genital ulcers. Cutaneous and visceral leishmaniasis can induce genital lesion, testicular amyloidosis, inflammation of epididymis, prostatitis, and sperm abnormality in human and animals. In addition, some epidemiological studies have reported that rates of protozoan infections in infertile patients are higher than healthy controls. The current review indicates that protozoan parasitic infections may be an important cause of infertility. Given the widespread prevalence of parasitic protozoa diseases worldwide, we suggest further studies to better understanding of relationship between such infections and infertility.

The prevalence of parasitic protozoan diseases in Iraq, 2016

Serine proteases are one of the biologically most important and widely distributed families of enzymes. Isolation of serine protease genes from organisms of widely diverged phylogenetic groups would provide a basis for studying their biological function, the relationship between structure and function, and the molecular evolution of these enzymes. Serine proteases for which little structural information is known are those that are important in the pathogenesis of parasitic nematode and protozoan diseases. Identification and isolation of protease genes from these organisms is a critical first step in understanding their function for the parasite and possibly suggesting innovative approaches to arresting parasitic diseases. Serine protease gene fragments were isolated from genomic DNA of the parasitic nematode Anisakis simplex by using degenerate oligonucleotide primers and the polymerase chain reaction. Primers were designed based upon the consensus sequence of amino acids flanking the active site serine and histidine residues of eukaryotic serine proteases. Four serine protease gene fragments from this parasite were sequenced and one is 67% identical to the rat trypsin II gene. Alignment of these two genes revealed that the intron-exon junctions are conserved between nematode and rat suggesting that this Anisakis serine protease is structurally and functionally similar to rat trypsin. The generality of this approach to identify serine protease genes from genomic DNA of two very divergent species, a parasitic protozoan and a mammal, was also confirmed. Genes for other enzymes or any protein with conserved structural motifs can be identified and isolated using this technology. Using a similar strategy, a cathepsin B-like cysteine (thiol) protease gene fragment was isolated from Caenorhabditis elegans DNA.

Protozoa are animal-like unicellular eukaryotes. They are not only cells but also independent organisms, with highly specialized cellular structures, physiological traits and unique phylogenetic positions, as well as strong relationships with the environment, natural resources, and human and animal protozoan parasitic diseases. Because of these characteristics, protozoa have long been considered important models in fundamental biological studies, such as cell biology, genetics, evolution, and applied fields, i.e., environmental biology, protozoan parasitic diseases’ treatment and prevention, as well as agriculture. In the past 50 years, protozoological studies in China, which started from traditional taxonomy, parasitology and ecology, have gradually advanced to most subdisciplines of biology, with systematic and in-depth studies. We have been focusing on and making considerable progress in biodiversity and systematics, epigenetics, cell biology and comparative genomics of marine ciliates, immunology, epidemiology and pathology of parasitic protozoa, evolutionary biology of flagellates and apicalcomplexa, and ecology of ciliated and amoeboid protozoa, with some of the studies leading the research field. This review briefly describes the recent progress in major protozoology laboratories in China, introduces research hotspots and key questions, and provides future research plans.

Developing vaccines to control protozoan parasites in ruminants: Dead or alive?

Chapter 13 - Drugs for giardiasis, trichomoniasis, and leishmaniasis

Chapter 7 - Terpenoids as Emerging Therapeutic Agents: Cellular Targets and Mechanisms of Action against Protozoan Parasites

Protozoan parasites of the genus Leishmania cause severe diseases that threaten human beings, both for the high mortality rates involved and the economic loss resulting from morbidity, primarily in the tropical and subtropical areas. This ancient eukaryote shows variable genetic diversity in their life cycle, wherein DNA topoisomerases play a key role in cellular processes affecting the topology and organization ofintracellular DNA. Kinetoplastid topoisomerases offer most attractive targets for their structural diversity from other eukaryotic counterparts and their indispensable function in cell biology Therefore, understanding the biology of kinetoplastid topoisomerases and the components and steps involved in this intricate process provide opportunities for target based drug designing against protozoan parasitic diseases.

Metacaspases are cysteine peptidases that could play a role similar to caspases in the cell death programme of plants, fungi and protozoa. The human protozoan parasite Leishmania major expresses a single metacaspase (LmjMCA) harbouring a central domain with the catalytic dyad histidine and cysteine as found in caspases. In this study, we investigated the processing sites important for the maturation of LmjMCA catalytic domain, the cellular localization of LmjMCA polypeptides, and the functional role of the catalytic domain in the cell death pathway of Leishmania parasites. Although LmjMCA polypeptide precursor form harbours a functional mitochondrial localization signal (MLS), we determined that LmjMCA polypeptides are mainly localized in the cytoplasm. In stress conditions, LmjMCA precursor forms were extensively processed into soluble forms containing the catalytic domain. This domain was sufficient to enhance sensitivity of parasites to hydrogen peroxide by impairing the mitochondrion. These data provide experimental evidences of the importance of LmjMCA processing into an active catalytic domain and of its role in disrupting mitochondria, which could be relevant in the design of new drugs to fight leishmaniasis and likely other protozoan parasitic diseases.

The global burdens of trypanosomiasis, malaria and leishmaniasis have continued to impoverish the developing countries. These protozoan parasitic diseases are still endemic in sub-Saharan Africa; and drug resistance and toxicities have further aggravated this situation. The aim of the study is to validate some folkloric claims on the uses of the selected plants in ethnomedicine in Nigeria. The study selected eight plants based on their use in the management of parasitic protozoan diseases and evaluated their antiprotozoal as well as cytotoxic activities. The methanol extracts of the plants were tested for in-vitro activities against Trypanosoma brucei rhodesiense (Tbr), Trypanosoma cruzi (Tcr), Leishmania donovani (Ldon) and Plasmodium falciparium as well as mammalian skeletal L6 myoblast for cytotoxicity. The results showed moderate to low in-vitro antiprotozoal and cytotoxic activities. Aspilia africana (IC50 8.15 ?g/mL) and Caesalpinia pulcherrima (IC50, 3.98 ?g/mL) showed significant in-vitro anti-Tbr activity with selectivity indices of 6 and 9.7 respectively. C. pulcherrima (IC50: 12.14 ?g/mL, Ldon; 14.0, Pfc), Dissotis rontundifolia (IC50: 18.45 ?g/mL, Tbr), Ficus glumosa flower (IC50: 16.05 ?g/mL, Tbr), Morinda morindiodes (IC50: 13.46 ?g/mL, Tbr), Senna alata (IC50: 10.51 ?g/mL, Tbr; 18.07 ?g/mL, Ldon) and Sphenocentrum jollyannum (IC50: 11.53 ?gmL, Tbr; 18.30 ?g/mL, Ldon; 13.26 ?g/mL, Pfc) showed moderate activities. Further separation of C. pulcherrima extract resulted in improved antileishmanial (IC50, SI: 4.57 ?g/mL, 4.6) and antiplasmodial (IC50, SI: 3.80 ?g/mL, 5.6) activities. This study has shown that some plants used in folk medicine in Nigeria could be potential sources of lead compounds for parasitic infection.

The diverse roles of monocytes in inflammation caused by protozoan parasitic diseases

Corrigendum to: The diverse roles of monocytes in inflammation caused by protozoan parasitic diseases

Drug repurposing for parasitic protozoan diseases.

Parasitic infection is a major healthcare problem that affects millions of the world’s population. Immigration and global warming have changed the natural distribution of parasitic diseases far removed from endemic areas. The respiratory system can be affected by a broad spectrum of helminthic and protozoal parasitic diseases. The diagnosis of parasitic infection of the respiratory system may be delayed due to myriad clinical and radiographic presentations of parasitic diseases which make the diagnosis of these entities challenging. Pulmonologists need to be familiar with the epidemiology, clinical presentation, pathophysiology, and bronchoscopic findings of parasitic lung diseases, in order to provide proper management in a timely fashion. This review provides a comprehensive view of both helminthic and protozoal parasitic diseases that affect the respiratory system, especially the central airways.