Ascaris Ova Research Articles

Bio-purification of Ascaris lumbricoides ova in a transformed Echinochloa pyramidalis wastewater treatment filter plant in the city of Yaounde (Cameroon)

The reuse of wastewater is widespread across the globe, especially in regions with water scarcity. Recycled water can be utilized in irrigation but if not treated effectively can pose risk for public health owing to the pathogens present in the recycled water used for irrigation Ascaris lumbricoides is a major soil-transmitted helminth that is highly infective to humans. The ova of A. lumbricoides are able to survive wastewater treatment, thus making it an indicator organism for effective water treatment and sanitation. Hence, Ascaris ova must be removed from wastewater matrices for the safe use of recycled water. The results of the observations of Ascaris lumbricoides eggs indicate a general density of 88 ± 72 ova.l-1. The highest density was 338 ova.l-1 obtained in fat and oil removal basin during the LRS. Although a density of 24 larvae/L was detected at the outlet. Overall, larvae decreased at the secondary treatment level with a general purification yield of 85%.

Contamination of Soils with Helminthic Eggs in Some Districts of Duhok Governorate / Kurdistan Region-iraq

Duhok Governorate, Kurdistan Region consists of many districts, where there is a high distribution of animals, presences of public parks and pastures. The present study was conducted in some of districts (Duhok center, Semel, Amadyia and Sharya) of Duhok Governorate, Kurdistan Region. The current study amid to determine the contamination of soils with helminthic ova and their correlation with the district residents, type of soil and presence of animals (Mainly stray Dogs and Cats). During this study, 533 soil samples were collected randomly from October 2021 to May 2022.  The samples were collected from different places such as dog shelters, general parks, groves, Hospital parks, near pastures, near sewage, private gardens, school parks, and near slaughter houses.  The collected samples were tested by flotation technique using saturated zinc sulphate (specific gravity 1.2).    The total rate of soil contamination with helminthic ova in all examined samples was 23.45% (125 / 533). The highest contamination rate with these ova was reported in soil samples examined from Sharya Camp 53.57% (30/56), while the lowest contamination rate was from Semel district 19.22% (49/255). The rates of ova in soils collected from Amadyia and Duhok center were 23.61% (34/144) and 15.38% (12/78), respectively. Regarding to the locations, soil samples examined from rural areas revealed high rate of contamination 29.33% (107/366) as compared with urban areas, in which the rate was 10.78% (18/167). The contamination rates with helminthic ova according to the type of soil, in clay soil was 26.54%, while in silty and sandy soils were 24.39% and 14.96%, respectively. The contamination rate of soils with these ova was higher in areas populated with animals mainly dogs and cats which was 26.44% (78/295) as compared to areas free from animals 19.75% (47/238) (19. Regarding to different places, the results showed that soils in places close to the sewage were highly contaminated with ova 50.00% (3/6), followed by those near pasture 37.50% (15/40), groves 35.56% (16/35), dog shelters 32.18% (28/87), school Parks 29.41% (10/34), near slaughter houses 27.50% (11/40), public places 21.05% (32/152). On the other hand, the lowest contamination of the soil with these ova was recorded in private gardens 8.26% (10/121), while the soil samples from hospital parks were free from parasitic ova. According to the type of helminths, ova of 6 helminthic genera were reported in all (533) examined soil samples, with Toxocara ova being the most prevalent helminths detected in 34 (6.38%), samples, then ova of Hymenolepis nana in 32 (6.00%), Taeniid ova in 26 (4.88%), Ancylostoma ova in 15 (2.81%), Ascaris ova in 12 (2.25%), and Trichuris ova in 6 (1.13%).  In conclusion, the soils of some districts were contaminated with different types of helminthic eggs. Therefore, the people of these districts will be at a high risk of acquiring infection with different species of these parasites when they get contacts with the soil

Potentials and challenges in the isolation and detection of ascarid eggs in complex environmental matrices

Ascarid infections constitute a major concern for both human and animal health risk assessment. Although being effectively transmitted by soil, water and contaminated food, reliable detection of ascarid eggs in environmental media often remains challenging. However, contamination of the environment with ascarid ova has gained more attention as a decisive part of proper risk assessment in recent years. Due to various factors, such as sample matrices, dissociation detergents and flotation solutions, defined and standardised protocols for the isolation of eggs from complex environmental matrices are difficult to establish and therefore limited. Thus, this study reviews common techniques used for the recovery of ascarid eggs from environmental media with special emphasis on sampling strategies, purification procedures and microscopic as well as molecular detection of egg contamination. Despite various advancements, mainly in the field of molecular methods leading to more reliable and sensitive detection, it can be concluded that there is still a need for unified guidelines for sampling and recovery of ascarid eggs derived from complex environmental matrices.

Diagnosis and therapeutic management of gastrointestinal parasitism among the captive population of Indian star tortoise (Geochelone elegans Schoepff, 1795) at Zoological Garden, Thiruvananthapuram, Kerala, India

Indian star tortoise (Geochelone elegans Schoepff, 1795) is a terrestrial herbivorous reptile that is classified under the vulnerable species of IUCN-Red List. The present communication reports the successful management of gastrointestinal parasitism due to co-infection with oxyurids and ascarid nematodes in the captive population of Indian star tortoise maintained at Zoological Garden, Thiruvananthapuram, Kerala, India. The diseased tortoise exhibited clinical signs like diarrhea, anorexia, and weight loss. Direct microscopic examination of pooled fecal sample identified the presence of oxyurid and ascarid ova. Therapeutic management involved a two-dose regimen of pyrantel pamoate given in a 2week interval at a dose rate of 5mg/kg body weight per orally. Complete parasitological clearance was observed 2weeks after initiating the therapy without any recurrence. The two-dose pyrantel pamoate protocol was found to be effective in controlling the parasitic burden of captive Indian star tortoise. Chemotherapy can be combined with managemental changes to nullify the possibility of re-infection.

Demographics of paediatric patients presenting with acute appendicitis: A 5-year retrospective review of hospitals served by the Department of Paediatric Surgery at the University of the Witwatersrand

Background. There are no recently published data on the incidence and demographics or perforation rates of paediatric patients from our local population presenting with acute appendicitis. Objective. To show the age and gender distribution of paediatric patients presenting with acute appendicitis within our communities, as well as demonstrating the incidence of perforated acute appendicitis in our paediatric population. Method. The study is a retrospective record review of all paediatric patients who presented with acute appendicitis to the Department of Paediatric Surgery at both Charlotte Maxeke Johannesburg Academic Hospital (CMJAH), and Chris Hani Baragwanath Academic Hospital (CHBAH) from June 2010 to September 2015. Data collected included all demographic data as well as histology results of patients who underwent appendectomies. Results. The total numbers of patients included in the study were 544; 234 at CHBAH, and 311 at CMJAH. The male-to-female ratio was 1.58:1. The mean age for presentation at both hospitals combined was 8.76 years. We found that 13.41% of paediatric patients with acute appendicitis in this cohort were under the age of 6 years. A histological review showed that 50.1% of patients in our cohort presented with complicated appendicitis, and we had a negative appendectomy rate of 8.4%. Histological results of patients under the age of 6 years revealed a higher negative appendicectomy rate of 11.4%. However, the incidence of complicated appendicitis in this age group was only 45.7%, which is lower than that reported in the literature. Three patients were found to have Enterobius vermicularis in the lumen of the appendix, and Ascaris ova were identified in one patient. Histology revealed a low-grade mucinous neoplasm in one patient. Conclusion. Acute appendicitis occurred at a median age of 8.76 years in our study population, with a male-to-female ratio of 1.58:1. We found that acute appendicitis occurred relatively more frequently in our patients under the age of 6 years compared with the incidence of acute appendicitis in this age group published elsewhere. Complicated appendicitis occurred in 50.1% of our patient population, with an increased frequency of perforated appendicitis occurring in our male population. However, complicated appendicitis occurred in only 44.7% of our patients below the age of 6 years, which is in stark contrast to published literature. Helminthic infections were rare associated pathogens in our study, and an unlikely underlying pathogen of acute appendicitis in our population.

Giardia and Cryptosporidium in children with diarrhea, Kufra, Libya, a North African migration route city.

Giardia and Cryptosporidium are common parasitic diarrhea agents of children contributing to childhood morbidity and mortality in developing countries. Major risk factors, based on the international literature, are expected to include domestic animals, fresh vegetables and drinking water and foodstuffs purchased from street vendors. These factors and sub Saharan migrants are common in the study area. Reports elsewhere indicate that person-to-person transmission is also important. To assess the prevalence Cryptosporidium and Giardia in children with diarrhea in the Kufra City hospital and to assess risk factors for cryptosporidiosis and giardiasis. A 10-month study, September 2013-June 2014 provided a fecal sample from 505 patients with diarrhea aged from 2 to 17 attending the outpatient clinics of local Kufra hospital, plus100 non symptomatic controls. Specimens were assayed for parasitic infection and for bacterial pathogens. Demographic information was obtained by questionnaire. Giardia was found in nearly 1/3 of the symptomatic population but few had Cryptosporidium. Mixed parasite infections were found in 1/7th of samples including: Shigella, Salmonella, Ascaris ova, E. coli, and E. histolytica. Infection frequency was age related, and risk factors included: domestic animals, foreign workers from Africa, contaminated fresh vegetables and drinking water. Cryptosporidium and Giardia were frequently associated with diarrhea in children in a remote desert agricultural community with many opportunities for infection. Contact with animals, foreign workers from Africa, fresh vegetables and drinking water sources contaminated with sewage materials are the likely modes of transmission of both organisms.

A modified approach to recover and enumerate Ascaris ova in wastewater and sludge.

A modified approach to recover and enumerate Ascaris ova in wastewater and sludge.

Aetio-pathological studies of digestive and respiratory affections in cattle calves

Aetio-pathological studies of digestive and respiratory affections was undertaken in cattle calves received for post mortem examination during a period of seven months (September, 2015 to March, 2016). Maximum age-wise mortality was noticed in age group of 1 to 3 months. Sex-wise mortality in cattle calves was more in females as compared to males. System-wise causes of death/mortality were highest due to combined involvement of both the digestive and respiratory systems. Pneumo-enteritis was the main affection noticed when there was combined involvement of both digestive and respiratory systems. Bacteriological studies of different samples collected from carcasses of cattle calves revealed that maximum bacterial species isolated was E. coli followed by Proteus spp., Klebsiella spp. and Staphyloccocus spp. Maximum number of bacteria species were isolated from intestine followed by lungs, heart blood and tracheal swab. The results of in-vitro drug sensitivity revealed that most of bacterial strains were sensitive to gentamycin and resistant to tetracycline. Examination of faecal samples of diarrhoeic/diseased and dead cattle calves revealed that Ascaris ova and Eimeria spp. was the major infection.

Study of opportunistic intestinal parasitic infections in people living with HIVand their relationship with immune status

Introduction: Diarrhea is one of the most common complaintspeople living with HIV(PLHIV), occurring in almost 90% of them. Intestinal parasites are one of the main causes of diarrhea in developing countries. Objective: The present study was undertaken to detect enteric parasites in PLHIV with different levels of immune status (CD 4+ Counts). Materials and Methods: The study included a total of 209 HIV seropositive subjects. Stool samples from each subject was examined microscopically for the presence of ova and cysts using wet mount preparations and stained smears (modified ZN stain). Results: Enteric pathogens were detected in 57 (27.27%) of the 209 patients. The parasites identified were Cryptosporidium (25), Isospora belli (3), Strongoloides larvae (2), Ascaris ova (1).In our study it was observed that the prevalence of cryptosporidium in HIV sero-positive subjects was 49.01%, 33.33%, 17.6% in those having CD4 500 cells/μl respectively. Conclusion: Intestinal opportunistic parasitic infections were detected in 27.27 % among HIV-seropositive patients. Cryptosporidiumis an important emerging pathogen in HIV-seropositive individuals with or without symptoms.Early detection of opportunistic intestinal parasitic infections using simple techniques like wet mount and modified ZN staining will help in the timely management and will improve the quality of life of HIV infected individuals.

Hookworm Infestation amongst Primary School Children in Enugu

Hookworm infestation was investigated amongst 273 primary school children from some random selected primary schools and a farming community, all in Enugu, Enugu State, South-East of Nigeria, between May and August 2008. The subjects were made up 110 (40.29%) males and 163 (59.71%) females. Stool samples 11 were collected from each subjects and examined macroscopically and microscopically for parasites using standard parasitological techniques. Out of 273 samples examined parasite 22 (8.06%) were positive for helminthic parasite and of this numbers of positives, ova of ascaris was 11 (50%), ova of hookworm 9 (40.9%), while mixed Infection with ova of ascaris/hookworm was 2 (9.1%). The age group 5-gyears had the highest number of parasites in the population studied 11 (50%). Females recorded a higher incidence rate of 17 (77.27%) than males 75 (22.72%). The age groups and sex distribution of positives showed statistical significance difference (p<0.05). Hookworm had a prevalence rate of 11 (4.0%) for single and mixed infection altogether. The age group 5-6 years had higher number of positives for hookworm, while females had the highest incidence rate for hookworm 9 (40.91%) than males 3 (13.64%). The difference in distribution of positive cases for hookworm between various age groups and sexes was statistically significant (P<0.05). The present work has established the presence of hookworm infestation amongst primary school children in Enugu. The need for enlightenment of these primary school children on the importance of personal and environmental hygiene and practice is hereby stressed.

Spatial patterns of soil-transmitted helminths in soil environment around Ibadan, an endemic area in south-west Nigeria

The dominant species and variation in prevalence pattern of Soil Transmitted Helminths (STHs) eggs and/or larva in soil around Ibadan metropolis south-west Nigeria were determined in order to project the monthly spread in relation to geographic location. A total of 720 soil samples collected between July 2014 and June 2015 from 3 locations within each of 5 selected Local Government Areas were examined for the presence of parasites using standard culture and concentration techniques. Mapping protocol was used for predictive risk prevalence of parasites. A total of 483 (67.1%) out of the soil samples examined had parasites. Ova of Ascaris and Trichuris species, adults and larva of Strongyloides and larva of hookworm species were encountered. The variation in distribution is statistically significant (x2=65.245; p&lt;0.05) in relation to months. November had the highest proportion (90.0%) of contaminated soil samples followed by February (78.3%) and the least proportion (50.0%) was observed in the month of September. Akinyele Local Government consistently had between very high and high rates of contaminated soil samples. Other local government areas had prevalence varying from high to low contaminated soil samples. The predictive patterns showed that Akinyele area in the northern suburb was the highest risk zone of STHs transmission. The high prevalence of parasites (67.1%) in soil samples examined showed a high risk of exposure to STH and explains the need for interventions to protect the population at risk of STH infections.Keywords: Endemic area; patterns, Ibadan; soil-transmitted helminthes; sanitation; Akinyele

Intrahepatic Duct Stones Harboring Ascariasis Ova: A Case Report.

Ascariasis lumbricoides is one of the most common helminthic infestations in humans. Despite the fact that the prevalence of ascariasis in developed countries has been decreasing, biliary ascariasis can cause serious complications, such as acute cholangitis, pancreatitis, and liver abscess. Here we presented a rare ascariasis-related complication—hepatolithiasis.A 60-year-old female patient had symptoms of recurrent cholangitis. Abdominal computed tomography scan revealed left intrahepatic duct stones with left liver lobe atrophy. Endoscopic retrograde cholangiopancreatography was performed, but the stones could not be removed due to left main intrahepatic duct stenosis. The patient was treated with left hemi-hepatectomy. Unexpectedly, Ascaris ova were found on the histopathological examination. She received antihelminthic therapy orally and was on regular follow-up without any complications.Our study indicates that clinicians should be aware of biliary ascariasis in patients with hepatolithiasis, though not living in endemic areas.

Prevalence and Determinants of Anaemia among Adolescent Girls in Secondary Schools in Yala Division Siaya District, Kenya

Approximately half of adolescent girls living in Sub-Saharan Africa are anemic. Anaemia is associated with lower physical work capacity, impaired cognitive functioning and lower school achievement among adolescents. This study was done to determine factors associated with the prevalence of anaemia among adolescent girls aged 14-18 years old within Yala division, Siaya District, Kenya. A mixed method multistage sampling was used to select 230 female students. Blood and stool samples were analysed for anaemia, malaria and worm infestation respectively. Questionnaires were used to assess intake of dietary iron. Results showed 26.5% , 41.3%, 7.4% prevalence anaemia (Hb <12.0 g/dl), malaria and ova of ascaris respectively. Factors that were significantly(P≤0.05) associated with anaemia were: the respondent’s age (OR 3.38 ), educational status of the fathers’, primary (OR=0.313) post-secondary (OR=0.343) inadequate daily dietary iron intake (OR=8.87), presence of malaria parasites (OR=3.68) and ova of ascaris (OR=11.94). The study concluded that anaemia is a public health problem among adolescents in this area. Interventions and strategies aimed at addressing effectively anemia in this population should therefore be targeted at the associated factors including parents especially fathers who should provide more bio available iron for the respondents in the diet.

Pathogens and Indicators in United States Class B Biosolids: National and Historic Distributions

This paper reports on a major study of the incidence of indicator organisms and pathogens found within Class B biosolids within 21 samplings from 18 wastewater treatment plants across the United States. This is the first major study of its kind since the promulgation of the USEPA Part 503 Rule in 1993, and includes samples before and after the Part 503 Rule was promulgated. National distributions collected between 2005 and 2008 show that the incidence of bacterial and viral pathogens in Class B mesophilic, anaerobically digested biosolids were generally low with the exception of adenoviruses, which were more prevalent than enteric viruses. No Ascaris ova were detected in any sample. In contrast, indicator organism numbers were uniformly high, regardless of whether they were bacteria (fecal coliforms) or viruses (phage). Indicators were not correlated with pathogen loads. Historic distributions were collected between 1988 and 2006 at one location in Tucson, AZ. By comparing data collected before and after 1993, the influence of the USEPA Part 503 Rule on indicator and pathogen levels within Class B biosolids can be inferred. In general, the bacterial indicators total and fecal coliforms decreased from the 1980s to present. Enteric virus concentrations after 1993 are much lower than those reported in other studies in the 1980s, although our values from 1988 to 1993 are not significantly different from our values obtained from 1994 to 2006. Presumably this is due to better and more consistent treatment of the wastewater, illustrating that the Part 503 Rule has been effective in reducing public exposure to pathogens relative to 17 yr ago. The percent reduction of both indicators and pathogens during anaerobic mesophilic digestion was between 94 and 99% for all organisms, illustrating that such treatment is effective in reducing pathogen loads.

An Unusual Cause of Iron Deficiency Anemia

Purpose: A 55-year-old black man originally from Caribbean Islands was referred to gastroenterology clinic for investigation of the cause of a newly diagnosed iron deficiency anemia found in the routine laboratory tests. His hemoglobin was 11.2 g/dL, MCV of 71 and concomitant ferritin of 18. Patient's medical history was remarkable for essential hypertension been treated by a thiazide diuretic, otherwise he was asymptomatic. He had no history of recent or past gastrointestinal bleeding or peptic ulcer disease. He denied abdominal pain, diarrhea, constipation, weight loss. He never had colorectal cancer screening nor had a family history of gastrointestinal cancers. His physical examination was unremarkable, including digital rectal examination with negative fecal occult blood. His laboratory data apart from the CBC and iron studies were within normal limits. A colonoscopy was scheduled which only showed scattered sigmoid colon diverticulosis. Subsequently an esophagogastroduodenoscopy with small bowel biopsy was scheduled which was unremarkable. Furthermore a small bowel capsule endoscopy was performed which demonstrated multiple “tubular shape structures consistent with Ascaris lumbricoides” in jejunum. Three stool samples for ova and parasites were sent and then a three-day regimen of mebendazole administered. Ascaris ova were seen in the stool samples, which were then became negative after anti-parasitic treatment. Patient received a course of iron supplementation and his hemoglobin as well as ferritin responded to treatment and remained normal after three months of follow up. Intestinal parasitic infections most commonly associated with iron deficiency anemia are: hookworms, schistosomiasis, and trichuris trichura infection. In contrast to other helminthes, A. lumbricoides does not feed on blood and does not cause mucosal damage severe enough to result in significant GI blood loss. However rare cases reported in the literature that recognized A. lumbricoides as an independent causative agent for iron deficiency anemia. A study in school children in Zanzibar identified the presence of A. lumbricoides as an independent explanatory factor of iron deficiency anemia in a multivariate analysis. Therefore our patient is one of the rare cases of A. lumbricoides causing iron deficiency anemia.

This Month in Gastroenterology

This Month in Gastroenterology

Class B Alkaline Stabilization to Achieve Pathogen Inactivation

Liming is a cost-effective treatment currently employed in many Class B biosolids production plants in the United States. A bench scale model of lime stabilization was designed to evaluate the persistence of viral, bacterial and parasitic pathogens. The survival of fecal coliforms, Salmonella, adenovirus type 5, rotavirus Wa, bacteriophage MS-2, Cryptosporidium parvum oocysts, Giardia lamblia cysts, and Ascaris lumbricoides ova was evaluated under lime stabilization conditions in a water matrix. Fecal coliforms and Salmonella were undetectable following 2 hours of lime stabilization, demonstrating a 7-log reduction. Adenovirus, MS-2 and rotavirus were below detectable levels following 2 h of liming, demonstrating a 4-log reduction. G. lamblia cysts were also inactivated. A. lumbricoides ova remained viable following 72 hours of liming as did C. parvum oocysts. While this study confirmed that Ascaris ova are resistant to liming, their scarcity in sludge and low recovery efficiencies limit their use as indicator. The persistence of C. parvum oocysts after exposure to lime, suggests that this parasite would be a better choice as indicator for evaluating biosolids intended for land application. The studies done with adenovirus Type 5, rotavirus Wa and male specific bacteriophage provided preliminary data demonstrating similar inactivation rates. Monitoring anthropogenic viruses is a time consuming, labor intensive and expensive process. If further studies could demonstrate that phage could be used as an indicator of other enteric viruses, enhanced monitoring could result in greater acceptance of land application of biosolids while demonstrating no increased public health threat.

Endoscopic ultrasonography in the evaluation of dilated common bile duct.

Abdominal ultrasonography (US) is the procedure of first choice in the evaluation of a dilated common bile duct (CBD). Dilated bile ducts and the level of obstruction can be reliably demonstrated with US, but the cause can be determined in only two thirds of patients. The aim of this prospective study was to assess the value of endoscopic ultrasonography (EUS) in detecting the cause of CBD dilatation in patients in whom US could not demonstrate the cause of dilation or in whom US revealed equivocal results. This 13-month study included the evaluation of 985 patients. Ninety consecutive patients found to have an enlarged CBD (diameter, > or =7 mm) of unexplained origin during US examination were included in this study. All patients were evaluated by EUS. Final diagnosis was determined by endoscopic retrograde cholangiopancreatography with or without sphincterotomy ( n = 72) and surgical exploration ( n = 17). The following diagnoses were made by EUS: choledocholithiasis in 40 patients, benign distal stricture in 8, choledochal cyst in 2, and ova of Ascaris in 1. The dilatation of CBD was found by EUS examination to be caused by a tumor in 13 cases. These included tumor of the papilla of the Vater in six patients, distal cholangiocarcinoma in five, and pancreatic head cancer in two. Endoscopic ultrasonography provided an accurate explanation for CBD dilatation in 70 of the 76 patients (92%). We conclude that the diagnostic strategy for cholestasis should include US as a first choice. When the diagnosis of biliary obstruction remains probable, EUS should be carried out. Endoscopic retrograde cholangiopancreatography with sphincterotomy should be reserved for therapeutic use rather than diagnostic.

Monitoring of a Municipal Sludge Entrenchment Site

AbstractRaw, highly limed, filter‐cake sludge (22% solid) was entrenched 18 ha of well‐drained, silt loam soil of the Manor (Typic Dystrochrept) and Glenelg (Typic Hapludalf) soil series in 1975 at a rate 2,200 wet metric tons/ha. As part of the overall evaluation of the environmental effects of sludge entrenchment, the USDA‐ARS, in cooperation with the Maryland Environmental Service, began to monitor the site in 1977 to determine the mineralization and movement of N, movement of heavy metals, and die‐off rate and movement of salmonellae, ascaris ova, and fecal indicators in the entrenched sludge and soil profile. Total N, NH4‐N, and Cl levels decreased in the entrenched sludge with time, and leached through the soil profile past the lowest sampling point, which was 100 cm below the trench bottom. Nitrate‐N was formed and migrated to the deepest sampling point, and direct evidence that denitrification occurred was lacking. Heavy metal losses from the entrenched sludge were negligible probably because the pH of the sludge after 45 months was above 7.0. A predictive equation based on decreases in sludge total N was developed for use as a tool for determining the age when the entrenched sludge was stablized. Fecal coliform concentrations were very low. Ascaris ova were not detected in the sludge prior to entrenchment or in samples taken during the monitoring period which, in part, may have been due to analytical limitations. Pathogen hazard associated with the entrenched, limed sludge appeared to be minimal. The major environmental effect of sludge entrenchment is possible contamination of ground water by N leached from the sludge.

The inactivation of faecal coliforms and Ascaris ova in faeces by lime

The inactivation effects of lime, when applied to faeces on faecal coliform bacteria and Ascaris lumbricoides ova, were investigated in the laboratory. A faecal coliform inactivation of about 5 orders of magnitude could be achieved at 19 g CaO l −1 (or initial sample pH of 12) and contact times over a 3 h period, while negligible reduction of faecal coliform bacteria was obtained at 5.7 g CaO l −1 (or initial sample pH of 9) with contact times from 3 to 48 h. However, only a 26.5% reduction of Ascaris ova was observed with 19 g CaO l −1 and a contact time of 48 h. Microscopic examination of the treated samples suggested the ovicidal effects of lime upon the Ascaris ova was of a low efficiency.