Integrated cryptosporidium assay to determine oocyst density, infectivity, and genotype for risk assessment of source and reuse water.

Cryptosporidium continues to be problematic for the water industry, with risk assessments often indicating that treatment barriers may fail under extreme conditions. However, risk analyses have historically used oocyst densities and not considered either oocyst infectivity or species/genotype, which can result in an overestimation of risk if the oocysts are not human infective. We describe an integrated assay for determining oocyst density, infectivity, and genotype from a single-sample concentrate, an important advance that overcomes the need for processing multiple-grab samples or splitting sample concentrates for separate analyses. The assay incorporates an oocyst recovery control and is compatible with standard primary concentration techniques. Oocysts were purified from primary concentrates using immunomagnetic separation prior to processing by an infectivity assay. Plate-based cell culture was used to detect infectious foci, with a monolayer washing protocol developed to allow recovery and enumeration of oocysts. A simple DNA extraction protocol was developed to allow typing of any wells containing infectious Cryptosporidium. Water samples from a variety of source water and wastewater matrices, including a semirural catchment, wastewater, an aquifer recharge site, and storm water, were analyzed using the assay. Results demonstrate that the assay can reliably determine oocyst densities, infectivity, and genotype from single-grab samples for a variety of water matrices and emphasize the varying nature of Cryptosporidium risk extant throughout source waters and wastewaters. This assay should therefore enable a more comprehensive understanding of Cryptosporidium risk for different water sources, assisting in the selection of appropriate risk mitigation measures.

Multiplex PCR for the detection and quantification of zoonotic taxa of Giardia, Cryptosporidium and Toxoplasma in wastewater and mussels.

Giardia duodenalis, Cryptosporidium parvum and Toxoplasma gondii are important parasitic protists linked to water- and food-borne diseases. The accurate detection of these pathogens is central to the diagnosis, tracking, monitoring and surveillance of these protists in humans, animals and the environment. In this study, we established a multiplex real-time PCR (qPCR), coupled to high resolution melting (HRM) analysis, for the specific detection and quantification of each G. duodenalis (assemblage A), C. parvum and T. gondii (Type I). Once optimised, this assay was applied to the testing of samples (n = 232) of treated wastewater and mussels (Mytilus galloprovincialis). Of 119 water samples, 28.6% were test-positive for G. duodenalis, C. parvum and/or both pathogens; of 113 mussel samples, 66.6% were test-positive for G. duodenalis, C. parvum and/or both pathogens, and 13.2% were test-positive for only T. gondii. The specificity of all amplicons produced was verified by direct sequencing. The oo/cysts numbers (per 5 µl of DNA sample) ranged from 10 to 64. The present multiplex assay achieved an efficiency of 100% and a R(2) value of >0.99. Current evidence indicates that this assay provides a promising tool for the simultaneous detection and quantitation of three key protist taxa.

Cloning and Iron Transportation of Nucleotide Binding Domain of Cryptosporidium andersoni ATP-Binding Cassette (CaABC) Gene.

Cryptosporidium andersoni ATP-binding cassette (CaABC) is an important membrane protein involved in substrate transport across the membrane. In this research, the nucleotide binding domain (NBD) of CaABC gene was amplified by PCR, and the eukaryotic expression vector of pEGFP-C1-CaNBD was reconstructed. Then, the recombinant plasmid of pEGFP-C1-CaNBD was transformed into the mouse intestinal epithelial cells (IECs) to study the iron transportation function of CaABC. The results indicated that NBD region of CaABC gene can significantly elevate the transport efficiency of Ca(2+), Mg(2+), K(+), and HCO3 (-) in IECs (P<0.05). The significance of this study is to find the ATPase inhibitors for NBD region of CaABC gene and to inhibit ATP binding and nutrient transport of CaABC transporter. Thus, C. andersoni will be killed by inhibition of nutrient uptake. This will open up a new way for treatment of cryptosporidiosis.

Simultaneous detection of Entamoeba histolytica/dispar, Giardia duodenalis and cryptosporidia by immunochromatographic assay in stool samples from patients living in the Greater Cairo Region, Egypt.

Gastrointestinal infection due to intestinal parasites is an enormous health problem in developing countries and its reliable diagnosis is demanding. Therefore, this study aimed at evaluating a commercially available immunochromatographic assay (ICA) for the detection of cryptosporidia, Giardia duodenalis, and Entamoeba histolytica/dispar for its usefulness in the Greater Cairo Region, Egypt. Stool samples of 104 patients who presented between October 2012 and March 2013 with gastrointestinal symptoms or for the exclusion of parasites at Kasr-Al-Ainy University Medical School were examined by light microscopy of wet mounts and the triple ICA. Microscopy revealed in 20% of the patients [95% confidence interval (CI), 13.5-29.0%] parasites with Hymenolepis nana, E. histolytica/dispar and Blastocystis hominis being the most frequent ones, but was not able to detect G. duodenalis and cryptosporidia, whereas ICA was positive in 21% (95% CI, 14.3-30.0%) and detected E. histolytica/dispar in 12.5% (95% CI, 7.3-20.4%), cryptosporidia in 6.7% (95% CI, 3.1-13.5%) and G. duodenalis in 15.4% (95% CI, 9.6-23.6%) of the patients. Detection of one or more pathogens was associated with access to water retrieved from a well or pump (p = 0.01). Patients between 20 and 29 years of age (p = 0.08) and patients with symptoms of 5 days or longer (p = 0.07) tended to have a higher risk to be infected than patients of other age groups or with shorter-lasting symptoms. In conclusion, the ICA was easy to perform and timesaving. Importantly, it enabled the detection of cryptosporidia, which cannot be found microscopically in unstained smears, demonstrated a higher sensitivity for the detection of G. duodenalis than microscopy, and was more specific for distinguishing E. histolytica/dispar from apathogenic amoeba.

A small Tim homohexamer in the relict mitochondrion of Cryptosporidium.

The apicomplexan parasite Cryptosporidium parvum possesses a mitosome, a relict mitochondrion with a greatly reduced metabolic capability. This mitosome houses a mitochondrial-type protein import apparatus, but elements of the protein import pathway have been reduced, and even lost, through evolution. The small Tim protein family is a case in point. The genomes of C. parvum and related species of Cryptosporidium each encode just one small Tim protein, CpTimS. This observation challenged the tenet that small Tim proteins are always found in pairs as α3ß3 hexamers. We show that the atypical CpTimS exists as a relatively unstable homohexamer, shedding light both on the early evolution of the small Tim protein family and on small Tim hexamer formation in contemporary eukaryotes.

ImmunoCard STAT! cartridge antigen detection assay compared to microplate enzyme immunoassay and modified Kinyoun's acid-fast staining technique for detection of Cryptosporidium in fecal specimens.

Cryptosporidium species infect humans and a wide range of animals worldwide; outbreaks of cryptosporidiosis have been reported in several countries. Routine diagnostic methods may be insufficient to demonstrate the presence of these organisms. The study assessed the diagnostic accuracy of the antigen detection immuno-cartridge test, ImmunoCard STAT! (Meridian Bioscience Inc., Cincinnati, OH, USA), compared to the combined gold standard: modified Kinyoun's acid-fast technique confirmed with the microplate enzyme immunoassay (EIA) for the detection of Cryptosporidium in fecal specimens. Three hundred fifteen formalin-fixed stool specimens were submitted for testing. The Kinyoun's acid-fast-stained smear revealed 24 positive samples for Cryptosporidium (of which 23 specimens were confirmed by the EIA) and 291 negative samples (of which 289 were negative by EIA). Agreement between the three used tests was shown in 22 positive and 288 negative samples for Cryptosporidium. Kappa score of agreement between the immuno-cartridge test and EIA was 0.957, p = 0.000. The sensitivity of the immuno-cartridge test was 96% (95% confidence interval (CI), 87% to 104%) and the total accuracy of the test was 97% (95% CI, 93-103). The ImmunoCard STAT! Cryptosporidium cartridge assay is easy to use and does not require specialized training or equipment and is useful in routine diagnosis and screening for Cryptosporidium especially where rapid, point of care testing is needed or where other reliable tests are unfeasible with a performance comparable to the EIA and acid-fast technique.

Multi-locus analysis of human infective Cryptosporidium species and subtypes using ten novel genetic loci.

BACKGROUND: Cryptosporidium is a protozoan parasite that causes diarrheal illness in a wide range of hosts including humans. Two species, C. parvum and C. hominis are of primary public health relevance. Genome sequences of these two species are available and show only 3-5% sequence divergence. We investigated this sequence variability, which could correspond either to sequence gaps in the published genome sequences or to the presence of species-specific genes. Comparative genomic tools were used to identify putative species-specific genes and a subset of these genes was tested by PCR in a collection of Cryptosporidium clinical isolates and reference strains. RESULTS: The majority of the putative species-specific genes examined were in fact common to C. parvum and C. hominis. PCR product sequence analysis revealed interesting SNPs, the majority of which were species-specific. These genetic loci allowed us to construct a robust and multi-locus analysis. The Neighbour-Joining phylogenetic tree constructed clearly discriminated the previously described lineages of Cryptosporidium species and subtypes. CONCLUSIONS: Most of the genes identified as being species specific during bioinformatics in Cryptosporidium sp. are in fact present in multiple species and only appear species specific because of gaps in published genome sequences. Nevertheless SNPs may offer a promising approach to studying the taxonomy of closely related species of Cryptosporidia.

90-kilodalton heat shock protein, Hsp90, as a target for genotyping Cryptosporidium spp. known to infect humans.

Small-subunit (SSU) rRNA-based methods have been commonly used in the differentiation of Cryptosporidium species or genotypes. In order to develop a new tool for confirming the genotypes of Cryptosporidium species, parts of the 90-kDa heat shock protein (Hsp90) genes of seven Cryptosporidium species and genotypes known to infect humans (C. hominis, C. parvum, C. meleagridis, C. canis, C. muris, C. suis, and the cervine genotype), together with one from cattle (C. andersoni), were sequenced and analyzed. With the exception of C. felis from cats and C. baileyi from birds, the Hsp90 genes of all tested Cryptosporidium species were amplified. Phylogenetic analysis of the hsp90 sequences from all these species is congruent with previous studies in which the SSU rRNA, 70-kDa heat shock protein, oocyst wall protein, and actin genes were analyzed and showed that gastric and intestinal parasites segregate into two distinct clades. In this study, the secondary products of hsp90 produced after PCR-restriction fragment length digestion with StyI and HphI or with BbsI showed that parasites within the intestinal or gastric clade could be differentiated from each other. These data confirm the utility of the Hsp90 gene as a sensitive, specific, and robust molecular tool for differentiating species and/or genotypes of Cryptosporidium in clinical specimens.

Comparative analyses and structural insights of new class glutathione transferases in Cryptosporidium species.

Cryptosporidiosis, caused by protozoan parasites of the genus Cryptosporidium, is estimated to rank as a leading cause in the global burden of neglected zoonotic parasitic diseases. This diarrheal disease is the second leading cause of death in children under 5 years of age. Based on the C. parvum transcriptome data, glutathione transferase (GST) has been suggested as a drug target against this pathogen. GSTs are diverse multifunctional proteins involved in cellular defense and detoxification in organisms and help pathogens to alleviate chemical and environmental stress. In this study, we performed genome-wide data mining, identification, classification and in silico structural analysis of GSTs in fifteen Cryptosporidium species. The study revealed the presence three GSTs in each of the Cryptosporidium species analyzed in the study. Based on the percentage identity and comprehensive comparative phylogenetic analysis, we assigned Cryptosporidium species GSTs to three new GST classes, named Vega (ϑ), Gamma (γ) and Psi (ψ). The study also revealed an atypical thioredoxin-like fold in the C. parvum GST1 of the Vega class, whereas C. parvum GST2 of the Gamma class and C. melagridis GST3 of the Psi class has a typical thioredoxin-like fold in the N-terminal region. This study reports the first comparative analysis of GSTs in Cryptosporidium species.

Microneme proteins in apicomplexans.

Microneme secretion supports several key cellular processes including gliding motility, active cell invasion and migration through cells, biological barriers, and tissues. The modular design of microneme proteins enables these molecules to assist each other in folding and passage through the quality control system, accurately target to the micronemes, oligimerizing with other parasite proteins, and engaging a variety of host receptors for migration and cell invasion. Structural and biochemical analyses of MIC domains is providing new perspectives on how adhesion is regulated and the potentially distinct roles MICs might play in long or short range interactions during parasite attachment and entry. New access to complete genome sequences and ongoing advances in genetic manipulation should provide fertile ground for refining current models and defining exciting new roles for MICs in apicomplexan biology.

[Real-time PCR in analyzing DNA extraction from Cryptosporidium oocysts].

OBJECTIVE: To compare the quality and quantity of DNA extracted from Cryptosporidium oocysts by different methods. METHODS: Cryptosporidium oocysts were treated with different kinds of lysis buffers from USA Promega (Promega) and Shanghai Generay (Generay) commercial DNA extraction kits, 2% Triton X-100 and 5% guanidine thiocyanate. The oocysts were then broken down by freeze-thawing, proteinase K and sonication. Genomic DNA was purified using the commercial kits or Chelex-100. Real-time PCR technique was used to determine the copies of Cryptosporidium oocyst wall protein (COWP) gene. The Promega commercial DNA extraction kit was used as control. RESULTS: The Promega kit resulted in a higher copy number of COWP gene [(6.45-9.86) x 10(6)] than that of Generay commercial DNA kit [(2.38-3.69) x 10(6)], 5% guanidine thiocyanate [(1.27-21.29) x 10(5)] or 2% Triton X-100 [(2.06-866.70) x 10(3)] , respectively. The method of freeze-thawing plus proteinase K plus sonication provided the highest copy number of COWP gene. CONCLUSION: The method of freeze-thawing + proteinase K + sonication is most effective. The effect of DNA extraction by Generay kit and 5% guanidine thiocyanate is similar to that of Promega kit.

Functionalized polystyrene microspheres as Cryptosporidium surrogates.

Cryptosporidium, a waterborne protozoan pathogen that can cause gastrointestinal illness, is often found in surface waters that are used to supply drinking water. Filtration is a major process to remove Cryptosporidium in drinking water treatment. However, interactions between oocysts and filter media are still unclear and no satisfactory surrogates have been identified for quantifying their filtration removal in porous media. In the present study, polystyrene microsphere with a size, density, and shape similar to Cryptosporidium was modified with glycoprotein or synthesized biomolecules to mimic the surface properties of live Cryptosporidium oocyst. Deposition kinetics between live Cryptosporidium/modified microspheres and filter media were studied at the molecular scale using a quartz crystal microbalance with dissipation monitoring (QCM-D) and at the laboratory-scale using sand-packed columns. Both QCM-D and column experiments underlined the importance of Cryptosporidium surface charge and hydrophobicity on their attenuation and transport in porous media. As compared to live Cryptosporidium, glycopolymer and zwitterionic polymer co- odified polystyrene microspheres (later called copolymers-modified microspheres) represent comparable surface properties, adsorption kinetics on filter surfaces, and transport and deposition behaviors in filter columns; hence were selected as appropriate Cryptosporidium surrogates. This study improves our understanding on how surface characteristics impact Cryptosporidium transport behaviors in porous media and contributes to our capacity to evaluate the attenuation of Cryptosporidium in natural and engineered aquatic environments.

Towards in silico lead optimization: scores from ensembles of protein/ligand conformations reliably correlate with biological activity.

Accurately ranking protein/ligand interactions and distinguishing subtle differences between homologous compounds in a virtual focused library in silico is essential in a structure-based drug discovery program. In order to establish a predictive model to design novel inhibitors of dihydrofolate reductase (DHFR) from the parasitic protozoa, Cryptosporidium hominis, we docked a series of 30 DHFR inhibitors with measured inhibition constants against the crystal structure of the protein. By including protein flexibility and averaging the energies of the 25 lowest protein/ligand conformers we obtained more accurate total nonbonded energies from which we calculated a predicted biological activity. The calculated and measured biological activities showed reliable correlations of 72.9%. Additionally, visual analysis of the ensemble of protein/ligand conformations revealed alternative ligand binding pockets in the active site. Using the same principles we then created a homology model of DHFR from Toxoplasma gondii and docked 11 inhibitors. A correlation of 50.2% between docking score and activity validates both the method and the model. The correlations presented here are particularly compelling considering the high structural similarity of the ligands and the fact that we have used structures derived from crystallographic data and homology modeling. These docking principles may be useful in any lead optimization study where accurate ranking of similar compounds is desired.

Evaluation of recombinant Cryptosporidium hominis GP60 protein and anti-GP60 chicken polyclonal IgY for research and diagnostic purposes.

In this study, a method for expressing Cryptosporidium hominis GP60 glycoprotein in Escherichia coli for production of polyclonal anti-GP60 IgY in chickens was developed aiming future studies concerning the diagnosis, prevention and treatment of cryptosporidiosis. The full-length nucleotide sequence of the C. hominis gp60 gene was codon-optimized for expression in E. coli and was synthesized in pET28-a vector. Subcloning was performed on several different strains of BL21 E. coli. Temperature, time and inducer IPTG concentration assays were also performed and analyzed using SDS-PAGE. The optimal conditions were observed at a temperature of 37 °C, with overnight incubation and 1 mM of IPTG. Purification was performed by means of affinity chromatography using the AKTA Pure chromatography system and the Hi-Trap™ HP column (GE Healthcare). The recombinant protein GP60 (rGP60) thus generated was used to immunize laying hens owing the production of polyclonal IgY. Western blot and indirect immunofluorescence showed that the polyclonal antibody was capable of binding to rGP60 and to Cryptosporidium parvum sporozoites, respectively. The rGP60 and the IgY anti-rGP60 generated in this study may be used as templates for research and for the development of diagnostic methods for cryptosporidiosis.

Hollow silica microspheres for buoyancy-assisted separation of infectious pathogens from stool.

Separation of cells and microorganisms from complex biological mixtures is a critical first step in many analytical applications ranging from clinical diagnostics to environmental monitoring for food and waterborne contaminants. Yet, existing techniques for cell separation are plagued by high reagent and/or instrumentation costs that limit their use in many remote or resource-poor settings, such as field clinics or developing countries. We developed an innovative approach to isolate infectious pathogens from biological fluids using buoyant hollow silica microspheres that function as "molecular buoys" for affinity-based target capture and separation by floatation. In this process, antibody functionalized glass microspheres are mixed with a complex biological sample, such as stool. When mixing is stopped, the target-bound, low-density microspheres float to the air/liquid surface, which simultaneously isolates and concentrates the target analytes from the sample matrix. The microspheres are highly tunable in terms of size, density, and surface functionality for targeting diverse analytes with separation times of ≤2min in viscous solutions. We have applied the molecular buoy technique for isolation of a protozoan parasite that causes diarrheal illness, Cryptosporidium, directly from stool with separation efficiencies over 90% and low non-specific binding. This low-cost method for phenotypic cell/pathogen separation from complex mixtures is expected to have widespread use in clinical diagnostics as well as basic research.

Structure of Cryptosporidium IMP dehydrogenase bound to an inhibitor with in vivo antiparasitic activity.

Inosine 5'-monophosphate dehydrogenase (IMPDH) is a promising target for the treatment of Cryptosporidium infections. Here, the structure of C. parvum IMPDH (CpIMPDH) in complex with inosine 5'-monophosphate (IMP) and P131, an inhibitor with in vivo anticryptosporidial activity, is reported. P131 contains two aromatic groups, one of which interacts with the hypoxanthine ring of IMP, while the second interacts with the aromatic ring of a tyrosine in the adjacent subunit. In addition, the amine and NO2 moieties bind in hydrated cavities, forming water-mediated hydrogen bonds to the protein. The design of compounds to replace these water molecules is a new strategy for the further optimization of C. parvum inhibitors for both antiparasitic and antibacterial applications.

A novel stereo bioactive metabolite isolated from an endophytic fungus induces caspase dependent apoptosis and STAT-3 inhibition in human leukemia cells.

The present study describes the anti-leukemic potential of a novel stereo bioactive secondary metabolite, (R)-5-hydroxy-2-methylchroman-4-one (HMC) isolated from a novel endophytic fungus source (Cryptosporiopsis sp. H2-1, NFCCI-2856), associated with Clidemia hirta. HMC inhibited cell proliferation of different cancer cell lines with IC50 values in the range of 8-55 µg/ml. The cytotoxicity window of HMC was 6-12 times lower in normal cells as compared to susceptible leukemic HL-60, MOLT-4 and K-562 cells. It persuades apoptosis through both intrinsic and extrinsic pathways in above leukemic cell lines, which was evident through Hoechst staining, Annexin-V binding, cell cycle analysis, loss of mitochondrial membrane potential (Δψm), release of cytochrome c, Bax, Bid, over-expression of apical death receptors, activation of caspase-3,-8,-9 and PARP (poly ADP ribose polymerase) cleavage. HMC induced caspase dependent apoptosis and robustly attenuate transcription factor, p-STAT-3 in myeloid and lymphoid leukemia cells. The mechanism of HMC arbitrated inhibition of p-STAT-3 was due to the activation of ubiquitin dependent degradation of p-STAT-3. Therefore, our study not only describes the anti-leukemic potential of HMC but also provides insights into how endophytes can be useful in discovery and development of novel anticancer therapeutics.

Immunodetection of the microvillous cytoskeleton molecules villin and ezrin in the parasitophorous vacuole wall of Cryptosporidium parvum (Protozoa: Apicomplexa).

Microvilli - actin - villin - ezrin - Cryptosporidium parvum The sporozoites and merozoites of the Apicomplexan protozoan Cryptosporidium parvum (C. parvum) invade the apical side of enterocytes and induce the formation of a parasitophorous vacuole which stays in the brush border area and disturbs the distribution of microvilli. The vacuole is separated from the apical cytoplasm of the cell by an electron-dense layer of undetermined composition. In order to characterize the enterocyte cytoskeleton changes that occur during C. parvum invasion and development, we used both confocal immunofluorescence and immunoelectron microscopy to examine at the C.parvum-enterocyte interface the distribution of three components of the microvillous skeleton, actin, villin and ezrin. In infected cells, rhodamine-phalloidin and anti-villin and anti-ezrin antibodies recognized ring-like structures surrounding the developing parasites. By immunoelectron microscopy, both villin and ezrin were detected in the parasitophorous vacuole wall surrounding the luminal and lateral sides of the intracellular parasite. In contrast, anti-beta and anti-gamma actin antibodies showed no significant labelling of the vacuolar wall. These observations indicate that the parasitophorous vacuole wall contains at least two microvillus-derived components, villin and ezrin, as well as a low amount of F-actin. These data suggest that C.parvum infection induces a rearrangement of cytoskeleton molecules at the apical pole of the host cell that are used to build the parasitophorous vacuole.

Short report: possible Cryptosporidium muris infection in humans.

Oocysts of cryptosporidia whose morphology resembled that of Cryptosporidium muris were found in the stool of 2 healthy girls in Surabaya, Indonesia. The oocysts were predominantly oval and measured 7.75+/-0.17 x 5.55+/-0.13 microm (mean+/-SD). The number of oocysts excreted were more than 10(5) per gram of stool. The oocysts were well stained with fluorescein-conjugated monoclonal antibody to Cryptosporidium. The specimens from both girls containing the oocysts showed a positive result by the polymerase chain reaction (PCR) using primers specific for the genus Cryptosporidium, but a negative result by the PCR using primers specific for C. parvum. The 2 girls passed oocysts for 5 and 6 days, respectively. They did not complain of any symptoms during the passage of oocysts.

Some gastro-intestinal parasites of zoonotic (public health) importance commonly observed in old world non-human primates in Kenya.

A study was undertaken to categorise some gastro-intestinal (GIT) parasites commonly observed in Kenyan non-human primates (NHPs) on the basis of their health implications for humans. Six species of locally available non-human primates, namely olive baboons (Papio cyanocephalus anubis), Vervet monkey (Cercopithecus aethiops), Sykes monkey (Cercopithecus mitis), Black and white colobus (Colobus abyssinicus), Debrazzas monkey (Cercopithecus neglectus) and Grey and Black mangabeys (Cercocebus torquatus and Cercocebus albigena) which were imported from Zaire (Democratic Republic of Congo) were sampled. Simple laboratory methods involving microscopic examination of stained faecal smears were used. Wet faecal smears stained with iodine and unstained controls were used for conventional parasites while acid fast staining was employed to detect Cryptosporidium oocysts. Both helminths and protozoan parasites were detected in varying rates in all primate species. Trichuris sp. was the most frequent helminth followed by Strongyloides fulleborni, Strongyles sp. and Schistosoma mansoni in that order. Entamoeba coli was the most common protozoan followed, respectively, by Balantidiun coli and Entamoeba histolytica. All primate species examined were infected with all the parasites listed except the black and white colobus. Cryptosporidium was found in both clinically normal and diarrhoeic baboons and vervets. Most taxa of parasites observed could prejudice human welfare directly through infection and causation of illness and indirectly through increased cost of livestock production and decreased availability of animal proteins. The potential of some of the agents to cause opportunistic infections in immuno-compromised persons was suggested as a likely threat to man's well-being. This would warrant such person's exemption from high risk operations at primate and other animal facilities in developing countries. Further, specific studies are needed to provide data on the epidemiology, socio-economic impact and pathogenicity of the primate parasites to other species of animals and man.