Helminth Ova Research Articles

Comparison of the quantity and quality of the microbiological content of sludge in countries with low and high content of pathogens

The parasites present in the residual sludge generate by the diverse treatment processes of residual water vary, depending on the socioeconomic and epidemiological conditions of different communities. And although data exist at the global level regarding the microbiological quality of sludge, these data are practically nonexistent in developing countries. Therefore, this project compares the content of the four principal groups of parasites in residual sludge from the United States and Mexico. The marked differences between the orders of magnitude found in the two countries (coliphages 10(3)-10(6) and 1.3 x 10(5) PFU/gTS, fecal coliforms 10(7)-10(10) and 10(7), Salmonella typhi 10(6)-10(8) and 10(3) MPN/gTS, Giardia lamblia 10(2)-10(4) and 10(2) cysts/gTS and helminth ova from 73-177 and <1 to 10 viable HO/gTS, respectively) will permit proposing real, effective and economical stabilization processes (undoubtedly different from those of industrialized countries), and will thus take advantage of the benefits represented by the reuse and disposal of sludge, in addition to developing regulations in agreement with the conditions of each region.

Changing mesophilic wastewater sludge digestion into thermophilic operation at Terminal Island Treatment Plant.

This paper describes the progress up to June 2000 for thermophilic digestion of wastewater sludge at the Los Angeles, California, Bureau of Sanitation's Terminal Island Treatment Plant. The development of the microorganism culture has followed a course similar to that seen at other successful plants for establishment of a stable, well-balanced thermophilic culture in a large digester, but at an accelerated pace. This study began with rapid heating, increasing the temperature of the 4500 m3 (1.2 mil. gal) digester to the target temperature of 55 degrees C at approximately 3 degrees C/d. A method of feeding to maximize the rate of culture development was used as feeding accelerated to approximately 400 m3/d (0.1 mgd). An initial rise of acid concentration (primarily acetate) was seen. Within two weeks, acid concentration declined and stabilized, indicating that acidogenic and methanogenic microbial communities came into balance. Coliform data indicate that digester disinfection was stably effective from the middle of April. The salmonella tests done to date satisfy the U.S. Environmental Protection Agency (U.S. EPA) class A specification. Testing with helminth ova and enteric viruses before and after the digester shows satisfaction of class A standard for those organisms. The present combination of low volatile fatty acids and low hydrogen sulfide is good news for odor control. The data show increases in volatile solids destruction and estimated gas production, compared with the previous mesophilic operation; however, large uncertainties have been calculated from the data. As the digester is now operating successfully at the current feed rate, there seems to be no barriers to processing the entire sludge production of the plant. Other results indicate that the U.S. EPA requirements for exceptional quality class A biosolids are likely to be achieved.

Growth of faecal coliforms and Salmonella spp. in physicochemical sludge treated with acetic acid

The use of advanced primary treatment (APT) to remove helminth ova from wastewater has raised the issue of treating the generated sludge to allow its reuse or disposal. Several studies have been performed in Mexico in order to treat the sludge with the main goal of destroying helminth ova and bacteria, one of them analysing the acid treatment. Previous research has demonstrated the feasibility of applying such a process using acetic acid to disinfect the sludge, but the potential for bacterial growth was still to be proved. The results of a growth study of faecal coliforms and Salmonella spp. in sludge treated with acetic acid are presented in this paper. Physicochemical sludge generated in a semi-rural area of Mexico City was treated using acetic acid in 6 different doses ranging from 3,700 to 22,000 ppm (w/w) and the concentrations of faecal coliforms, Salmonella spp., and total and volatile solids, were monitored after 30 minutes, and 8, 21 and 35 days. Average initial concentrations in sludge were 1.1 x 10(8) MPN/g TS and 1.5 x 10(5) MPN/g TS for faecal coliforms and Salmonella spp., while pH, total and volatile solids were 5.4, 5.0% and 73% respectively. Apparently, some acidified samples presented anaerobic activity, observed as a change in sludge coloration, as well as bacterial growth. pH of the treated samples with less than 18,400 ppm raised from the initial value of approximately 4.0 up to 5.9 units, while samples with 18,400 and 22,000 ppm maintained the pH close to 4. Total and volatile solids did not present important changes except in the untreated sample where they were reduced by 0.3 and 3.4% respectively. Samples treated with more than 14,700 ppm of acetic acid did not present any increase in bacterial density. Additionally, concentrations of faecal coliforms and Salmonella spp. in untreated sludge were reduced throughout the time, in contrast to samples treated with doses lower than 14,700 ppm that showed some growth, which suggests that the use of acetic acid in doses lower than 15,000 ppm stimulates in some way the growth of these bacteria.

Removal of microorganisms in different stages of wastewater treatment for Mexico City

In this study the removal of a diversity of microorganisms during different stages of treatment was evaluated. The process scheme consisted of Advanced Primary Treatment (APT), sand filtration, and chlorine disinfection. During the first 2 stages, fecal coliforms were reduced from 1.24 x 10(9) to 1.2 x 10(8) MPN/100 mL and helminth ova were reduced to less than 1 ova/L. Nevertheless, to obtain an effluent water quality that meets the microbiological standards recommended by the World Health Organization (1989) and the Mexican norm for water destined for agricultural reuse it was necessary to disinfect the effluent with a chlorine dose of 12 mg/L for a 3 hour contact time. Under these conditions, fecal coliforms were reduced from 1.2 x 10(9) to 5.8 x 10(1) MPN/100 mL, Salmonella spp. from 5.0 x 10(8) MPN/100 mL to below the detection limit, Pseudomonas aeruginosa from 2.0 x 10(5) MPN/100 mL to below the detection limit, and protozoan cysts from 1052 to 31 cysts/L. Regrowth of bacteria was never observed during the 48 hours period following disinfection. The active chlorine was primarily in the form of chloramines thus reducing the formation of other potentially carcinogenic disinfection byproducts.

The Effectiveness of Vermiculture in Human Pathogen Reduction for USEPA Biosolids Stabilization

A field experiment tested the feasibility of vermicomposting as a method for eliminating human pathogens to obtain United States Environmental Protection Agency (USEPA) Class A stabilization in domestic wastewater residuals (biosolids). The experimental site was at the City of Ocoee's Wastewater Treatment Facility in Ocoee, Florida, and Class B biosolids were used as the earthworm substrate. Two windrows of biosolids 6 m long were heavily inoculated with four human-pathogen indicators, fecal coliforms, Salmonella spp., enteric viruses and helminth ova. The test row was seeded with earthworms, Eisenia fetida. The quantity of E. fetida was calculated at a 1:1.5 wet weight earthworm biomass to biosolids ratio and the earthworms allowed time to consume the biosolids and stabilize the biosolids. The test indicated that all of the pathogen indicators in the test row were decreased more than in the control row within 144 hours. The test row samples showed a 6.4-log reduction in fecal coliforms compared with the control row, which only had a 1.6-log reduction. The test row samples showed an 8.6-log reduction in Salmonella spp., while the control row had a 4.9-log reduction. The test row samples showed a 4.6-log reduction in enteric viruses while the control only had a 1.8-log reduction. The test row samples had a 1.9-log reduction in helminth ova while the control row only had a 0.6-log reduction. Dr. Jim Smith, Senior Environmental Engineer and Pathogen Equivalency Commission (PEC) Chair, for the USEPA, indicated by personal communications, that a three- to four-fold reduction in indicator organisms would be sufficient to warrant serious consideration of vermicomposting as an effective stabilization methodology (Smith 1997). These results in conjunction with pilot project results strongly indicate that vermicomposting could be used as an alternative method for Class A biosolids stabilization. This was obtained statistically by vermicomposting.

Intestinal parasitic infections, with a special emphasis on cryptosporidiosis, in Amerindians from western Venezuela.

The prevalences of intestinal parasites and intensities of helminth infections were studied in two Amerindian villages in Venezuela. Single stool specimens were collected from 303 individuals from Saimadoyi and 130 from Campo Rosario. Wet mounts, iron-hematoxylin-stained smears, and formalin-ether concentrates were examined for the presence of parasites; modified Ziehl-Neelsen carbol-fuchsin staining of 10% formalin-preserved stool was used to identify Cryptosporidium parvum. Helminth ova counts were made using the standard smear egg count technique. Mixed infections (Campo Rosario = 69.9%, Saimadoyi = 71.6%) were frequent. Overall infection rates with one or more species (Campo Rosario = 79.2%, Saimadoyi = 95.4%; P < 0.01) and with any protozoans (Campo Rosario = 60.8%, Saimadoyi = 72.3%; P < 0.05) were high and predominant (P < 0.05) in Saimadoyi. Cryptosporidiosis was identified in 38 subjects (8.8%) in both villages; 60.6% were asymptomatic carriers. The mean egg counts of helminths were heavier in Campo Rosario (P < 0.05), which was probably due to the drastic reduction of their lands along with their low standard of living. This study documents the change of intestinal parasitism pattern and deterioration of the health of Amerindians by the process of acculturation.

Evaluation of lacto-phenol cotton blue for wet mount preparation of feces

The use of lacto-phenol cotton blue (LPCB) stain for wet mount preparation of stools to demonstrate intestinal parasites by routine microscopy was evaluated in this study. LPCB-stained trophozoites and cysts and helminthic ova could easily be detected and identified in LPCB wet mounts of stools. The stain is recommended for routine use in the wet mount preparation of stools in a parasitology laboratory.

In vitro response of Haemonchus contortus larvae harvested during different times of the patent period to anthelmintics

Three commercially available ruminant anthelmintics and an investigational drug were evaluated for effects on the motor function/motility of third stage (ensheathed) Haemonchus contortus. Helminth ova were collected at one, five, nine and 13 weeks during the patent period, cultured to the third larval stage and assayed for sensitivity to four different drugs. All four drugs (100 and 10 micrograms ml-1) significantly affected the motility of third stage H contortus larvae cultured from eggs passed at each of the times examined. However, the investigational drug (p-toluoyl chloride phenylhydrazone, 10 micrograms ml-1) had a significantly greater effect on the motility of larvae harvested at 13 weeks than those cultured at nine weeks (32 per cent difference). No other significant differences in the motility response during the patent period were observed.

Gastrointestinal parasites of the eastern cottontail (Sylvilagus floridanus) in central Pennsylvania.

During a 3 year period, 186 eastern cottontails (Sylvilagus floridanus) were trapped from two areas and examined for helminth and protozoan parasites. Fecal samples from 139 were evaluated for coccidia and helminth ova. Nine species of coccictia were identified: Eimera audubonii, E. azul, E. environ, E. honessi, E. maior, E.minima, E. neoirresidua, E. neoleporis, and E. sylvilagi. Ova from 5 helminth species were found: Cittotaenia sp., Hastilesia tricolor, Passalurus sp., a trichostrongyle-type nematode species, and Trichuris sp. Five helminths were recovered from stomachs and small intestines: Cittotaenia sp. H. tricolor, Obeliscoides cuniculi,, Passalurus ambiguus, and Trichostrongylus calcaratus.

The destruction of pig helminth ova and larvae in a slurry treatment process.

It was established that a thermophilic system for the treatment of pig slurry at 55 degrees C rapidly killed the free living stages of three common pig parasites. This treatment could be beneficially incorporated in any pig slurry recycling process, whether to land or to animals.

Infectious Disease Hazards of Landspreading Sewage Wastes

AbstractMajor increases are currently taking place in the United States in the application of sewage wastes to agricultural land. This paper reviews literature relating to the question of whether such applications involve hazard from human disease organisms. Evidence on the matter is still inadequate. Processed sewage wastes often contain residual pathogenic viruses, bacteria, cysts of protozoa, and ova of helminths, but most sewage‐related disease outbreaks have been attributed to use of raw sewage waste water, raw sludges, or night soils on food crops consumed raw, to contamination of drinking water from septic tanks, or to consumption of raw shellfish from sewage‐polluted waters. Although subject to relatively high levels of exposure to pathogens in aerosols, waste water treatment plant workers appear to be unaffected, but data on this are limited. Percolation of waste water at a moderate rate through soils of medium to fine texture removes most bacteria and viruses; pathogen movement in surface runoff water may present a greater hazard for spreading disease. Techniques that completely disinfect sludges may fail to stabilize them so that putrefaction is a problem. Properly conducted composting stabilizes raw sludge and destroys most pathogens. Certain fungi and actinomycetes generated during composting may have allergenic potentialities of import for workers at sludge composting sites.

Helminthiasis in selected children seen at the University of Benin Teaching Hospital (UBTH), Benin City, Nigeria

Illiteracy, poverty with associated poor environmental sanitation practices have been implicated in the heavy burden of helminthiasis among children. The objective of this cross-sectional survey is to determine the impact of parents' level of education on the intestinal helminthic status of children. All patients, 0-15 years totaling 1030 who visited the communicable disease clinic of the University of Benin Teaching Hospital, Benin City, from October, 2001 to March 2002 were included in this study. However, only 207 of the enlisted patients submitted faecal samples for examination and constituted the study population. Tool for data collection was structured questionnaire that was researcher administered to mother/caregivers after informed consent was obtained. Information sought in the questionnaire included sex and age of the subjects and level of education of their parents. Formol ether concentration method was used for stool examination while intensity was estimated using McMaster counting chamber technique. Of the 207 faecal samples examined 46(22.2% ) had ova of helminths while 161(77.85% ) had none. More school children, 40(19.3% ), than pre-school children, 6(2.9% ) had helminth ova in their faecal samples and the difference was found to be statistically significant (P < 0.05). More females, 28(13.5% ) than males, 18(8.7% ) were infected but the difference was however not statistically significant (P > 0.05). Intestinal helminth ova seen in order of prevalence include A. lumbricoides, 23(11.1% ); hookworm, 12(5.8% ); T. trichiuria, 8(3.8% ); Schistosoma mansoni, 2(1.0% ); Strongyloides stercoralis, 1(0.5% ) while multiple infection was recorded in 11(5.3% ) patients. Intensity of infection was low. The difference between the means for A. lumbricoides, T. trichiuria and multiple infection by age were found to be statistically significant P < 0.001; P < 0.05; P < 0.001, respectively. Mother's level of education more than father's level of education seemed to influence the pattern of intestinal helminthiasis among the children but the association was not found to be statistically significant (P > 0.05). Prevalence and intensity of infection was low probably due to periodic antihelminthic treatment offered by the health authorities. Improvement in mother's level of education brought about decrease in prevalence of intestinal helminthiasis among the children. Therefore, improvement in female education should be encouraged to reduce the incidence of communicable disease in the family.

An Evaluation Of Cellophane Thick Smear Technique For Mass Stool Examination.

To evaluate the Kato's cellophane thick smear techcique in detection ability of various helminth ova, authors examined 1,843 nationwidely collected stool specimens by the two methods, formalin-ether technique and cellophane thick smear technique. And the results were analyzed. 1. The positive rates of following helminth ova were superior in cellophane thick smear technique to those of formalin-ether technique: Ascaris lumbricoides(62.3% : 51.1%), Taenia species (1.5% : 0.9%). The difference in A. lumbricoides ova detection is highly significant one. The overall positive rate for helminths ova was also higher in Kato's method (92.3% : 90.0%). 2. The positive fates of following helminth ova were infrior in cellophane thick smear technique to those of formalin-ether technique: Hookworm (5.8% : 14.6%), Trichostrongylus orientalis(3.2% : 17.8%), Clonorchis sinensis(8.3% : 11.0%), Metagonimus yokogawai (0.6% : 1.7%) and Hymenolepis nana(0.05% : 0.3%). The positive rate for the ova of Trichocephalus trichiurus by the two methods was incidentally same, 74.1%. 3. The causes of inferior positive rates in some helminth ova by cellophane thick smear technique were shortly discussed and suggests some opinions in improvement of detection ability.

A comparison of Kato thick smear technique with zinc sulphate flotation method, for the detection of helminth ova in faeces.

A comparison of Kato thick smear technique with zinc sulphate flotation method, for the detection of helminth ova in faeces.

GRAZING SYSTEMS FOR EWES AND LAMBS

Two experiments were conducted to compare forward creep grazing of lambs with other grazing management systems for ewes and lambs. In the first experiment, forward creep grazing with and without creep feeding of concentrates was compared with rotational grazing, using 7 ewes with single lambs per plot of [Formula: see text] acres. The first lambs reached market weight by the 57th day of the experiment, at which time the average lamb gains were higher on the creep grazed-creep fed groups, but there was no difference in the gains on the other two systems. The experiment was continued for 35 days and during this period the lamb gains on the creep grazed plots were higher than on the rotationally grazed areas. This later period coincided with a period of reduced herbage growth due to below normal precipitation. The average daily gains for the entire experimental period were.45,.51 and.57 pounds for rotational, creep, and creep fed-creep grazed systems respectively.In the second experiment, forward creep grazing was compared with rotational grazing and free range grazing, using a higher stocking rate of 8 ewes and 10 lambs per plot. The average daily gains for the experiment were.38,.40 and.34 pounds for rotational, creep grazed, and free range systems respectively. The differences between grazing systems were not statistically significant at P = 0.05. Both the ewe and lamb gains were lower on the free-range system than on the other systems. The ewe gains were higher on the rotationally grazed areas than the forward creep grazed areas in both experiments. This indicates that forward creep grazing of lambs can be advantageous under conditions where herbage is abundant.Evidence obtained from helminth ova counts on fecal samples, and examination of representative digestive tracts of the lambs marketed, indicated that the forward creep grazing of lambs reduced but did not prevent a build-up of internal parasites.

The merthiolate iodine formaldehyde concentration technique for the detection of parasitic material in faecal samples.

The results of the examination of 543 faecal specimens by the Merthiolate Iodine Formaldehyde Concentration (M.I.F.C.) technique, Willis's salt flotation method and by direct saline smear are given.The appearances of helminth ova and protozoan parasites in M.I.F.C. preparation are described.The M.I.F.C. method showed a much greater efficiency for the detection of helminth ova over the other two methods. It did not prove as satisfactory for the detection of protozoan parasites. Effective concentration of trophozoite forms was not observed. The possible reasons for this are discussed.It is proposed to adopt this method in combination with the direct saline smear for routine use in this laboratory.

The Effect of Diet on the Length of Third Stage Larvae Produced by Adult Haemonchus contortus Harbored by Lambs

designated a control animal and the feces of these animals were examined frequently for helminth ova. They were consistently found to be free of ova except for a few Strongyloides sp. Twenty-seven to 30 days following the administration of the larvae, feces were collected from all of the lambs. The feces of each of the control lambs was crushed by hand, mixed with charcoal and placed, several millimeters thick, on two thicknesses of moistened filter paper in Petri dishes. The feces from each of the infected lambs were crushed and placed in saturated sodium chloride solution in large centrifuge tubes. With the aid of centrifugation the eggs were separated from the fecal material and were gathered from the surface of the solution. The eggs were then washed once with 0.9 percent sodium chloride solution and three times with tap water. Aliquots of the resulting samples were removed and the number of eggs counted. Approximately 8,000 fertilized eggs were placed on each control lamb's feces in the Petri dishes. The scheme for culturing was as follows:

Amebiasis: controlled linear studies on nondysenteric and mild hepatic forms in Egyptians.

Excerpt Since the early part of this century many experienced observers—Osler,1Councilman,2Musgrave,3Craig,4to mention only a few—have noted the absence of a history of appreciable diarrhea or any ...

A New Modification of the McMaster Slide for Use in Potato-root Eelworm Investigations

The original McMaster slide (Gordon and Whitlock, 1939) has been extensively used for investigations involving dilution counts on helminth ova in faeces. In view of the simplicity inherent in its design and use, attempts have been made to utilize it for obtaining estimates of the viable egg contents of cysts of Heierodera rostochiensis, the use of a modified McMaster slide for this purpose being described by Fenwick (1942). Fenwick's slide differed from the original in that the counting area was marked on the floor of the counting chamber instead of its roof; this modification resulted from the use of water as a diluent instead of semi-saturated brine as used in faecal examinations. The capacity of the original McMaster slide (0·15 ml.) was, however, found to be too small to give a reasonably large count from a batch of 100 cysts unless the degree of dilution was so small that efficient agitation before the withdrawal of a sample for counting was difficult.

A Modification of the Zinc Sulphate Centrifugal Flotation Technique for the Concentration of Helminth Ova and Protozoan Cysts in Faeces

(1947). A Modification of the Zinc Sulphate Centrifugal Flotation Technique for the Concentration of Helminth Ova and Protozoan Cysts in Faeces. Annals of Tropical Medicine & Parasitology: Vol. 41, No. 1, pp. 43-45.