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Sarcocystis spp. infects water buffaloes (Bubalus bubalis) causing sarcocystosis. In the present study, Sarcocystis fusiformis was recognized in Egyptian water buffaloes based on histological observation and molecular analysis of internal transcribed spacer 1 (ITS1), 18S ribosomal RNA (18S rRNA) and cytochrome c oxidase subunit I (COX-1) gene fragments. Chemotherapy and vaccines against Sarcocystis spp. could potentially target proteases because they may play a crucial role in the infection. Cysteine proteases are multifunctional enzymes involved in vital metabolic processes. However, the involvement of proteases in S. fusiform infection has not yet been characterized. Here, the purification and study on some biochemical properties of protease isolated from cysts of S. fusiform were carried out. Protease with a molecular weight of 100 kDa was purified. LC–MS/MS analyzed the protein sequence of purified protease and the data suggested that the enzyme might be related to the cysteine protease. The purified protease exhibited maximum activity at pH 6 and a temperature of 50 °C. The Michaelis–Menten constant (Km), the maximum velocity (Vmax), and the turnover number (Kcat) were determined. The complete inhibition effect of cysteine inhibitors indicated that the purified enzyme is a cysteine protease. The results suggested that S. fusiform proteolytic enzyme may be necessary for parasite survival in water buffaloes by digesting host tissues. Therefore, cysteine protease could be a suitable target for vaccinations. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the prevalence and molecular detection of Cryptosporidium spp. in catfish (Clarias gariepinus). Methods: A total of 300 Carias gariepinus fish were collected from two freshwater sources: the Nile River (180) and drainage canals (120). The stomach and intestine epithelium of each individual fish sample were screened by modified Ziehl–Neelsen (mZN) staining technique for the detection of Cryptosporidium oocysts followed by the serological survey for detection of Cryptosporidium antibodies using Enzyme-Linked Immunosorbent Assay (ELISA) and molecular characterization using complemented DNA polymerase chain reaction (cPCR). Results: ELISA showed higher prevalence of 69.3% than that prevalence obtained by mZN, 64% for the total examined Clarias gariepinus fish. Also, higher prevalence of Cryptosporidium infection 65.5% and 75.8% obtained by ELISA than 61.1% and 68.3% by mZN, in both fish groups from Nile River and Drainage canal, respectively. PCR analysis revealed the expected positive bands at 1056 bp. DNA sequencing and phylogenetic analysis proved that the positive-PCR Cryptosporidium isolate identified in the present study was Cryptosporidium molnari. Conclusion: Freshwater fishes (Clarias gariepinus) are subjected to a high infection rate with Cryptosporidium spp.; the drainage canals obtained fishes showed higher prevalence than that collected from Nile River which indicates an important public health problem and a potential risk of drainage canals in Egypt. ELISA showed higher prevalence of cryptosporidiosis than mZN, for the total examined Clarias gariepinus fish and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium molnari. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii (T. gondii) is a worldwide distribution infects a wide variety of mammals, including humans. The present study aimed to detect the efficacy of soluble and whole T. gondii antigens propagated in specific pathogen-free of embryonated chicken egg (SPF-ECE) used to improve the potency of serological assays for diagnosis of toxoplasmosis in equids and human. Total of 220 serum samples from 170 equids (90 donkeys and 55 horses and 25 mules) and 50 humans were collected from different governorates in Egypt during the period from October 2017 to March 2018. Crude T. gondii tachyzoites antigens from low or high passages propagated in mice or SPF-ECE was used for modifying some serological tests. The experiment showed that the mortality rate of T. gondii for 103 and 104 low passages were 6/8 (75%) and 7/8 (88%) dead embryos but, lower mortality rate in high passage T. gondii were 4/8 (50%) and 5/8 (63%) dead embryos, respectively. No mortality or inflammatory signs were observed in control of negative groups. In equids sera were examined by S-ELISA using soluble T. gondii antigen propagated in SPF-ECE showed the highest positive results 26 (28.8%), followed by LAT 37 (22%) and MAGPT 36 (21.17%). While, W-ELISA and IFAT used whole T. gondii antigen prepared in SPF-ECE were 35 (20.58%) and 28 (19.41%) showed highly positive results than the same test used the whole antigen prepared in mice. The highest seroprevalence of T. gondii in human and donkeys were 19/50 (38%). and 26/90 (28.88%), more than mules were 6/25 (24%) and horses were 9/55 (16.3%) examined by S-ELISA respectively. SPF-ECE is considered an appropriate experimental model for isolation and propagation of T. gondii tachyzoites, and their soluble antigens used in serological tests (S-ELISA, LAT, and MAGPT) have sensitivity and specificity more than the whole antigen and provided reliable diagnostic tools for detection of toxoplasmosis in human and equids. [ABSTRACT FROM AUTHOR]

Electron microscopy (EM) is a very good tool in the biological researches. It is mainly used in the morphological description of adult and immature stages of ticks. In this review, different applications of EM in identification of ticks were discussed. In general, the applications of EM have been presented in four topics: morphological descriptions, comparative taxonomy, detection of pathogens in tick organs, and drug efficacy on ticks. EM was used in the description of a new tick or description of a tick which was described before to clarify additional characters that were not observed before by light microscope (LM). It is obvious that the EM provides all the morphological characters clearly in details. However, ticks have ornamented characters on their scutum, so it is necessary to use LM as well as molecular biology to confirm the morphological characters. EM is also used in detection of ultrastructure of pathogenic organisms in the cell lines or tissues of tick vectors that infected experimentally or naturally by pathogen. EM also helps to know the effect of new drugs or its mode of action by photography of the alterations which may occur on the integument or other tick organs such as the digestive system. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is an obligate intracellular zoonotic protozoan. Pulmonary involvement is common in immunocompromised hosts but rarely occurs in immunocompetent ones. Rat pulmonary involvement could be considered as a good representative model for study of human toxoplasmosis infection to either acute toxoplasmosis, chronic toxoplasmosis, or disseminated toxoplasmosis in human immunodeficiency virus (HIV) patients. Forty Swiss-Webster rats were divided into four groups each ten rats: group 1, non-infected and untreated (normal); group 2, acute infected non-treated; and groups 3 and 4, chronic infected non-treated and corticosteroid treated respectively. Lung tissue and blood samples were taken during acute and chronic stages for parasitological and histopathological study and serological assay. Acute and chronic states revealed the presence of viable toxoplasma tachyzoites and bradyzoites in lung tissue respectively. Serological assay showed different results in acute and chronic infections. The histopathological changes in acute rat group showed that per alveolar septa has been swollen due to swelling of the pneumocystis type I and II and the lining cells of the alveoli became low cuboidal in shape. The histopathological changes in chronic untreated rat group showed that the majority of alveolar walls were thickened due to swelling of the alveolar epithelial cells and mononuclear inflammatory cells and the bronchioles due to hyperplasia of its lining epithelium. Some of the blood vessel wall contained large number of chronic Toxoplasma cysts and surrounded by mononuclear cells. While chronic corticosteroid-treated rat group showed perivascular and alveolar edema with congested per alveolar blood capillaries and alveolar edema with compensatory emphysema of some others. The study concluded that toxoplasmosis is a great of interest, serious, and often a life-threatening disease in immune-deficient patients and sometimes in immunocompetent ones. Pulmonary toxoplasmosis should be considered in the differential diagnosis in potentially HIV-infected patients with respiratory symptoms and bilateral pulmonary infiltrates. Early diagnosis and initiating specific good therapy is essential. [ABSTRACT FROM AUTHOR]