Zebra mussels (Dreissena polymorpha) are effective sentinels of water quality irrespective of their size

Zebra mussels (Dreissena polymorpha) are recognised biomonitors in determining the presence and viability of the human\ud waterborne pathogens Cryptosporidium parvum, C. hominis, Giardia intestinalis and microsporidia in surface waters. This study\ud investigated whether the size of zebra mussels is a significant factor in the concentration of protozoan Cryptosporidium oocysts,\ud Giardia cysts and microsporidian spores. Zebra mussels were collected in Lough Arrow, a small Irish lake, which is utilized for\ud drinking water abstraction and is subject to agricultural and human wastewater pollution drivers, both recognised risk factors for\ud human waterborne pathogens. Zebra mussels were cleaned, divided into size (5 mm) interval classes based on their shell length\ud and made up to 150 g samples (wet weight with shell). Combined fluorescence in situ hybridization (FISH) and\ud immunofluorescent antibody (IFA) techniques were utilized as biomolecular techniques to assess the presence and concentration\ud of the pathogens. PCR analysis provided source-tracking information on human and animal pollution sources. There was no\ud significant relationship between the size of D. polymorpha and pathogen loads in similar sized samples, indicating that different\ud sites in the same or different waterbody can be compared in terms of relative concentrations of human waterborne parasites\ud irrespective of the zebra mussels’ size. Cryptosporidium was the most abundant species, with lower counts of Giardia and the\ud microsporidian Encephalitozoon hellem, respectively. Cryptosporidium oocysts and Giardia cysts were detected in zebra mussel\ud samples at all three lake water abstraction points. A lake transect showed a decline in Cryptosporidium with increasing distance\ud from a stream discharging sewage. Samples from agricultural sites indicated faecal inputs contaminated with these pathogens.\ud Species identification implicated both human and animal faecal inputs to the lake from treated effluent, septic tanks, and\ud agriculture. The research demonstrates the efficacy of zebra mussels as sentinels of water quality irrespective of their size

Novel and promising compounds to treat Cryptosporidium parvum infections

No fully effective approved drug therapy exists for Cryptosporidium infections of immunocompetent and immunocompromised patients. Here, we investigated 11 benzimidazole derivatives carrying substituted thioalkyl and thiobenzyl groups at position 2 of benzimidazole nucleus and additional substituents at the benzene part of benzimidazole for inhibition of the in vitro growth of the intestinal protozoan parasite, Cryptosporidium parvum. Three of them, i.e., 5-carboxy-2-(4-nitrobenzylthio)-1H-benzimidazole, 5,6-dichloro-2-(4-nitrobenzylthio)-1H-benzimidazole, and 4,6-dichloro-2-(4-nitrobenzylthio)-1H-benzimidazole, (compounds 5, 7, and 8) were the most active (IC50 28–31 μM). The concentration of compounds 5, 7, and 8 that caused 50% growth inhibition in human enterocytic HCT-8 cells by a quantitative alkaline phosphatase immunoassay was comparable with those obtained for paromomycin

Novel and promising compounds to treat Cryptosporidium parvum infections

No fully effective approved drug therapy exists for Cryptosporidium infections of immunocompetent and immunocompromised patients. Here, we investigated 11 benzimidazole derivatives carrying substituted thioalkyl and thiobenzyl groups at position 2 of benzimidazole nucleus and additional substituents at the benzene part of benzimidazole for inhibition of the in vitro growth of the intestinal protozoan parasite, Cryptosporidium parvum. Three of them, i.e., 5-carboxy-2-(4-nitrobenzylthio)-1H-benzimidazole, 5,6-dichloro-2-(4-nitrobenzylthio)-1H-benzimidazole, and 4,6-dichloro-2-(4-nitrobenzylthio)-1H-benzimidazole, (compounds 5, 7, and 8) were the most active (IC50 28–31 μM). The concentration of compounds 5, 7, and 8 that caused 50% growth inhibition in human enterocytic HCT-8 cells by a quantitative alkaline phosphatase immunoassay was comparable with those obtained for paromomycin

Detection of Avian Malaria Infections in Wild and Captive Penguins

Forster, 1781) were tested by enzyme-linked immunosorbent assays for the presence of avian malaria antibodies (Ab). Plasmodiurn falciparum sporozoite (R32tet32) and gametocyte (P.F.R27) antigens were used. Specificity of anti-5". demersus, anti-duck, anti-chicken, and anti-turkey IgG labeled with alkaline phosphatase was determined for homologous and heterologous sera of 8 avian species (including 6 penguin species). The penguin conjugate was the most specific for the various penguin species immunoglobulins. It was possible to detect penguin immunoglobulins at a dilution of 10~4•". The relative binding of anti-S. demersus IgG was equal to relative binding of commercial conjugates. Kinetic profiles and overall magnitudes of malarial Ab detected by the 2 antigens were not significantly different. Antarctic P. adeliae were negative for malarial Ab, all New Zealand M. antipodes were positive, and the positivity prevalence of the remaining penguins ranged from 33 to 92%. Antibody titers and the prevalence of infection of wild S. demersus were significantly lower than those reported for captive North American S. demersus

Maximizing Recovery and Detection of Cryptosporidium parvum Oocysts from Spiked Eastern Oyster (Crassostrea virginica) Tissue Samples▿

Numerous studies have documented the presence of Cryptosporidium parvum, an anthropozoonotic enteric parasite, in molluscan shellfish harvested for commercial purposes. Getting accurate estimates of Cryptosporidium contamination levels in molluscan shellfish is difficult because recovery efficiencies are dependent on the isolation method used. Such estimates are important for determining the human health risks posed by consumption of contaminated shellfish. In the present study, oocyst recovery was compared for multiple methods used to isolate Cryptosporidium parvum oocysts from oysters (Crassostrea virginica) after exposure to contaminated water for 24 h. The immunomagnetic separation (IMS) and immunofluorescent antibody procedures from Environmental Protection Agency method 1623 were adapted for these purposes. Recovery efficiencies for the different methods were also determined using oyster tissue homogenate and hemolymph spiked with oocysts. There were significant differences in recovery efficiency among the different treatment groups (P < 0.05). We observed the highest recovery efficiency (i.e., 51%) from spiked samples when hemolymph was kept separate during the homogenization of the whole oyster meat but was then added to the pellet following diethyl ether extraction of the homogenate, prior to IMS. Using this processing method, as few as 10 oocysts could be detected in a spiked homogenate sample by nested PCR. In the absence of water quality indicators that correlate with Cryptosporidium contamination levels, assessment of shellfish safety may rely on accurate quantification of oocyst loads, necessitating the use of processing methods that maximize oocyst recovery. The results from this study have important implications for regulatory agencies charged with determining the safety of molluscan shellfish for human consumption