Elution and reconcentration of polioviruses adsorbed on coal from water samples.

Viruses adsorbed on coal particles in the form of coal bed could efficiently be recovered with elution of 6% beef extract solution in Mcllvaine buffer at pH 7.1. Significant reduction in large volume of eluate could be achieved by employing modified organic flocculation technique to obtain virus concentrate. Modified organic flocculation technique involves addition of 0.02% bovine albumin in eluate. Enteroviruses were adsorbed to flocs which were formed at pH 3.5 and were recovered by centrifugation followed by solublization of flocs in a small volume of 0.15 M disodium hydrogen phosphate solution at pH 9.5. The recovery of viruses ranged from 87.9% to 97.3% with an average of 92.2%.

Use of bituminous coal for concentration of enteroviruses from sewage and effluent.

A method has been developed for concentration of enteroviruses from untreated and treated domestic wastewater using bituminous coal bed as a virus adsorbent. A bed made from 1.5 g of 120 mesh coal powder was used for concentrating enteroviruses from 100 ml of clarified sewage at different pH values with and without addition of AlCl3. To enhance the adsorption of viruses, requisite quantities of aluminium chloride were added so that a final concentration of 0.0005 M could be achieved. At pH 3.0 maximum adsorption (82.8%) of poliovirus type 1 from artificially contaminated clarified sewage was observed without addition of AlCl3. However, at pH 5.0 maximum virus adsorption of 98.7% was achieved after addition of aluminium chloride. An average recovery of 86.9% of adsorbed viruses at pH 5.0 was achieved from coal bed with 3% flocculating beef extract at pH 9.5. This method for concentration of enteroviruses incorporating use of coal was compared with that of Millipore membrane filter method applied to raw sewage and clarified sewage. The results obtained from the methodology using coal as adsorbent was subjected to Student's "t" test and it was observed that its efficiency is confirmed for recovery of enteroviruses from raw and nonclarified sewage. These results are also comparable with that obtained with MF method. The results presented in this paper are indicative of the potential of this method for both treated and raw sewage.

Methodology for recovery of indigenous viruses from primary sludge.

Freon extraction method for recovery of viruses from primary sludge has been studied with sonication and the beef extract eluation methods. Several variables within the freon extraction method were worked out and it was observed that equal volume of 10% buffered beef extract (pH 7.0), as that of the sludge sample, was required for optimum virus elution. Eluate decontamination with antibiotics, dilution and plaquing over BGM cell cultures using the overlay medium without phenol red, fortified with 1.7% milk powder resulted in best recoveries without any cytotoxicity to the cell cultures. A sample volume of 20 ml primary sludge was sufficient for quantification of viruses.

Incidence of cataracts in the mobile eye hospitals of Nepal.

The incidence of cataract in Nepal was determined from data collected in 14 mobile eye hospitals (called 'eye camps'). Of a total of 12,217 patients examined in the out-patient department (OPD), cataract surgery was performed on 2,163. The percentage of cataract patients in the OPD was less in the mountains (13.8%) than in the Tarai plains (19.8%). In the inhabitants of the mountains, the majority of whom belong to the Tibeto-Birman race, cataracts appeared at a significantly later age in both males and females compared to the people of the plains, who are mostly Indo-Aryan. Cataracts were discovered in both groups at a younger age in women than in men.

Detection of viruses in drinking water by concentration on magnetic iron oxide.

Discharge of raw domestic wastes containing human enteric viruses into water courses, consumption of untreated water from canals, streams, and shallow wells in villages, and cross-contamination of water in the distribution system because of intermittent water supply in urban areas continue to cause widespread outbreaks of infectious hepatitis in India. To detect a low number of viruses in 50- to 100-liter samples of water, a method was developed with magnetic iron oxide as the virus adsorbent. Poliovirus-seeded dechlorinated tap water, adjusted to pH 3.0 and 0.0005 M AlCl3, was filtered through a 10-g bed of iron oxide sandwiched between two AP20 prefilter pads held in a 142-mm-diameter, stainless-steel holder. Virus was eluted from iron oxide by recirculating three times a 100-ml volume of 3% beef extract, pH 9.0. The eluate was reconcentrated to 5 ml by adjusting to pH 3, adding 1 g of iron oxide, stirring for 30 min, and eluting the readsorbed virus with 5 ml of beef extract, pH 9.0. Virus recovery varied from 60 to 80%. Using the above method, we took a survey of drinking water at three locations in Nagpur during 1976 and found the presence of virus in 7 of 50 samples. The quantity of virus recovered ranged from 1 to 7 plaque-forming units per 30 to 60 liters. Virus was detected in some samples even with residual chlorine. No coliforms were detected in the virus-positive samples.