There has been an explosion of descriptions of new species of Cryptosporidium during the last two decades This has been accompanied by confusion regarding the criteria for species designation, largely because of the lack of distinct morphologic differences and strict host specificity among Cryptosporidium spp A review of the biologic species concept, the International Code of Zoological Nomenclature (ICZN), and current practices for Cryptosporidium species designation calls for the establishment of guidelines for naming Cryptosporidium species All reports of new Cryptosporidium species should include at least four basic components: oocyst morphology, natural host specificity, genetic characterizations, and compliance with the ICZN Altogether, 13 Cryptosporidium spp are currently recognized: C muris, C andersoni, C parvum, C hominis, C wrairi, C felis; and C cannis in mammals; C baileyi, C meleagridis, and C galli in birds; C serpentis and C saurophilum in reptiles; and C molnari in fish With the establishment of a framework for naming Cryptosporidium species and the availability of new taxonomic tools, there should be less confusion associated with the taxonomy of the genus Cryptosporidium The clarification of Cryptosporidium taxonomy is also useful for understanding the biology of Cryptosporidium spp, assessing the public health significance of Cryptosporidium spp in animals and the environment, characterizing transmission dynamics, and tracking infection and contamination sources

Cryptosporidium Taxonomy: Recent Advances and Implications for Public Health (Review)

Purpose of Review: Microsporidia have emerged as causes of opportunistic infections associated with diarrhea and wasting in AIDS patients. This review describes recent reports of microsporidiosis in HIV-infected individuals and the growing awareness of microsporidiosis in non-HIV-infected populations. Recent Findings: Microsporidia were only rarely recognized as causes of disease in humans until the AIDS pandemic. Implementation of combination antiretroviral therapy (cART) to curtail HIV replication and restore immune status drastically reduced the occurrence of opportunistic infections including those due to microsporidia in HIV-infected individuals. In developing countries where cART is not always accessible microsporidiosis continues to be problematic. Improvement of diagnostic methods over the previous 25 years led to identification of several new species of microsporidia many of which disseminate from enteric to systemic sites of infection and contribute to some unexpected lesions. Among non-HIV-infected but immune-suppressed individuals microsporidia have infected organ transplant recipients children the elderly and patients with malignant disease and diabetes. In otherwise healthy immune-competent HIV seronegative populations self-limiting diarrhea occurred in travelers and as a result of a foodborne outbreak associated with contaminated cucumbers. Keratitis due to microsporidiosis has become problematic and a recent longitudinal evaluation demonstrated that non-HIV-infected individuals seropositive for microsporidia who had no clinical signs continued to intermittently shed organisms in feces and urine. Summary: Greater awareness and implementation of better diagnostic methods are demonstrating that microsporidia contribute to a wide range of clinical syndromes in HIV-infected and non-HIV-infected people. As such microsporidia should be considered in differential diagnoses if no other cause can be defined.

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Microsporidiosis: Not just in AIDS patients

Identification of endophytic Bacillus velezensis ZSY-1 strain and antifungal activity of its volatile compounds against Alternaria solani and Botrytis cinerea

https://digital.csic.es/bitstream/10261/212834/4/1-s2.0-S2405676618300441-main.pdf

Toxoplasma gondii infection and toxoplasmosis in farm animals: Risk factors and economic impact.

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving “One Health” initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

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Cryptosporidium and Giardia in Africa: current and future challenges

Antileishmanial and cytotoxic potential of essential oils from medicinal plants in Northern Tunisia

The present study was conducted to investigate the serological survey of Toxoplasma antibodies in local.horses from three major regions: a neighbourhood of a city in the North (Sidi Thabet), a neighbourhood of a city on the coast (Monastir) and a neighbourhood of a city in the middle (Battan) of Tunisia (North of Africa). A total of 158 serum samples were obtained from clinically healthy horses which consisted of 111 (32 female, 79 male) 2-10 years old and 47 (11 female, 36 male) older than 10 years. All of the horses were tested for antibodies to T. gondii using the Modified Agglutination Test (MAT). According to MAT results, antibodies to T. gondii were found in 28 (17.7%) of 158 sera with the titers of 1:20 in 20 horses, 1:40 in 1 horse, 1:80 in 2 horses, 1:160 in 2 horses, 1:320 in 1 horse and ≥1:640 in 2 horses. Anti-T. gondii antibodies were found in 18 (16.2%) of 111 horses (2-10 years old) and 10 (21.2%) of 47 horses (older than 10 years old). Six (13.9%) out of 43 female had anti-toxoplasma antibodies and 22 (19.1%) from 115 males remained positive. Statistically significant differences in age groups and genders were observed between the seropositive and seronegative horses using the Chi square X(2) test. Other statistical correlation was also reported concerning horse breed.

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Seroprevalence of Toxoplasma gondii infection among horses in Tunisia.

The present study aimed to investigate the anti-Candida activity of ten essential oils (EOs) and to evaluate their potential synergism with conventional drugs. The effect on secreted aspartic protease (SAP) activity and the mechanism of action were also explored. The antifungal properties of essential oils were investigated using standard micro-broth dilution assay. Only Cinnamomum verum, Thymus capitatus, Syzygium aromaticum, and Pelargonium graveolens exhibited a broad spectrum of activity against a variety of pathogenic Candida strains. Chemical composition of active essential oils was performed by gas chromatography-mass spectrometry (GC-MS). Synergistic effect was observed with the combinations C. verum/fluconazole and P. graveolens/fluconazole, with FIC value 0.37. Investigation of the mechanism of action revealed that C. verum EO reduced the quantity of ergosterol to 83%. A total inhibition was observed for the combination C. verum/fluconazole. However, P. graveolens EO may disturb the permeability barrier of the fungal cell wall. An increase of MIC values of P. graveolens EO and the combination with fluconazole was observed with osmoprotectants (sorbitol and PEG6000). Furthermore, the combination with fluconazole may affect ergosterol biosynthesis and disturb fatty acid homeostasis in C. albicans cells as the quantity of ergosterol and oleic acid was reduced to 52.33 and 72%, respectively. The combination of P. graveolens and C. verum EOs with fluconazole inhibited 78.31 and 64.72% SAP activity, respectively. To our knowledge, this is the first report underlying the mechanism of action and the inhibitory effect of SAP activity of essential oils in synergy with fluconazole. Naturally occurring phytochemicals C. verum and P. graveolens could be effective candidate to enhance the efficacy of fluconazole-based therapy of C. albicans infections.

Antifungal mechanism of the combination of Cinnamomum verum and Pelargonium graveolens essential oils with fluconazole against pathogenic Candida strains

Prevalence and species distribution of Cryptosporidium spp. were determined among 633 immunocompetent children less than five years of age and 75 patients hospitalized for immunodeficiency who lived in northern Tunisia. Microscopy was used for initial screening to detect positive samples and a nested polymerase chain reaction and restriction fragment length polymorphism analysis was used to determine the species. Cryptosporidium spp. was identified in 2.7% of cases (19 stool samples), and there was a significant difference between samples collected from immunocompromised patients and those collected from healthy children (10.7% versus 1.7%). Prevalence was also significantly higher in diarrheal specimens than in formed specimens (6.3% versus 1.6%). Cryptosporidium hominis and C. parvum were responsible for most Cryptosporidium spp. infections (78.9%). Cryptosporidium hominis was more prevalent in children from urban areas than in those from rural areas, and C. parvum was found with similar prevalence rates in the two populations. Cryptosporidium meleagridis was identified in four children on farms.

Identification of cryptosporidium species infecting humans in Tunisia.

Several volatile organic compounds (VOCs) producing endophyte bacteria were isolated from the leaves of olive trees and tested for their antifungal activity against several pathogenic fungi. An antagonistic strain called P2 showed 97 % of homology with Pseudomonas sp. strains on the basis of its 16S rDNA sequence and biochemical properties. P2 strain drastically inhibited the growth of Rhizoctonia solani mycelia (86 %) at 5 day-post-confrontation (dpc) and strongly reduced fungi infection on potato slices at 107 bacteria ml−1 for 3 and 7 dpc. P2 strain was also positive for protease activity as well as siderophore production. Light microscopy analysis showed that treatment of R. solani mycelia with P2 strain induced thickening of the cell-wall, vesiculation of protoplasm and blockage of fungal hyphae branching. VOCs analysis using GC–MS allowed the detection of two major products with m/z of 93.9910 and 125.9630 corresponding to dimethyl disulfide and dimethyl trisulfide respectively. VOCs-producing P2 strain could be a promising agent in the protection of tuber crops against fungal diseases.

Rym Essid

Papers

Antileishmanial and cytotoxic potential of essential oils from medicinal plants in Northern Tunisia

Seroprevalence of Toxoplasma gondii infection among horses in Tunisia.

Antifungal mechanism of the combination of Cinnamomum verum and Pelargonium graveolens essential oils with fluconazole against pathogenic Candida strains

Identification of cryptosporidium species infecting humans in Tunisia.

Antifungal activity of volatile compounds-producing Pseudomonas P2 strain against Rhizoctonia solani