Duodenalis Infection Research Articles

Giardia and Cryptosporidium in water buffaloes (Bubalus bubalis)

A cross-sectional survey of Giardia duodenalis and Cryptosporidium parvum infection in the water buffalo (Bubalus bubalis) was carried out in central Italy. A geographical information system (GIS) was constructed utilizing as data-layers the topographic base map and the digital aerial photographs of the study area, as well as the geo-referenced points of all the buffalo farms. The survey was conducted on a sample of 90 farms, selected using a grid approach followed by proportional allocation. For this purpose, a grid representing quadrants of 5 x 5 km was overlaid on the study area within the GIS. As a result, the study area was divided in equal quadrants, and the number of farms sampled in each quadrant was proportional to the total number of study population in that quadrant. On each farm, faecal samples were collected per rectum from three to five asymptomatic buffalo calves, aged from 1 to 9 weeks. The total number of faecal samples collected was 347. Each faecal sample was tested for the presence of copro-antigens of G. duodenalis and of C. parvum using two commercially available enzyme-linked immunosorbent assays. Out of the 90 farms, 27 (30.0%) resulted positive for G. duodenalis and 22 (24.4%) for C. parvum. Co-infection was found in ten (11.1%) farms. With respect to animals, out of the 347 faecal samples, 63 (18.1%) were found to have antigens of G. duodenalis and 51 (14.7%) of C. parvum. Co-infection was found in ten buffalo calves (2.9%). The results of the logistic regression models showed a positive association between the positivity to G. duodenalis and the presence of sheep on farm and between the positivity to C. parvum and the high number of buffaloes on farms. No significant co-infection between the two protozoa was found. In conclusion, the findings of the present study, derived from a systematic territorial survey planned with GIS, are noteworthy because they provided additional data on C. parvum and the first evidence of G. duodenalis infection in water buffaloes.

First studies on Giardia duodenalis in the water buffalo

A cross-sectional survey of Giardia duodenalis infection in the water buffalo was carried out in Central Italy. The survey was conducted on a sample of 90 farms, selected using a grid approach within a Geographical Information System, followed by proportional allocation. On each farm, faecal samples were collected from three to five asymptomatic buffalo calves, aged from 1 to 9 weeks (total number = 347). Each faecal sample was tested for the presence of copro-antigens of G. duodenalis using a commercially available ELISA. Out of the 90 farms, 27 (30.0%) resulted positive. With respect to animals, out of the 347 faecal samples, 63 (18.1%) were found to have antigens of G. duodenalis. The results of the logistic regression model showed a positive association between the positivity to G. duodenalis and the presence of sheep on farm.

Giardia duodenalis and Cryptosporidium spp. in a veterinary college bovine teaching herd

In a preliminary study, we commonly identified Giardia duodenalis in adult dairy cattle from a veterinary college teaching herd. Therefore, the present study was carried out in order to better understand the potential of adult cattle to act as a source for G. duodenalis infections for students and staff at the veterinary college. Fecal samples were collected bi-weekly from this herd of adult cattle ( n = 30) over an 8-month period to determine the prevalence of G. duodenalis and Cryptosporidium spp. within the herd. Nested PCR followed by DNA sequencing was then performed on a subset of positive samples in order to better understand the zoonotic potential of these infections. Every cow was sampled between 11 and 18 times, depending on the date the animal joined the teaching herd. In total, 507 fecal samples were collected from 30 different cows and examined for cysts and oocysts using epifluorescence microscopy. G. duodenalis prevalence during the course of the study ranged from 37% (11/30) to 64% (18/28), with a mean of 49%. Cumulative G. duodenalis prevalence was 73% (22/30). Zoonotic G. duodenalis assemblage A genotype was identified in 43% (6/14) of the G. duodenalis-positive samples on which PCR and genetic sequencing were successfully performed. G. duodenalis assemblage E was identified in 57% (8/14) of these samples. Cryptosporidium spp. oocysts were not detected in the feces of any cows during the study period. The presence of the zoonotic G. duodenalis assemblage A in 43% of the sequenced samples indicates that there is a potential risk of infection for students and staff at this research and teaching facility, although the roles of cows as sources of giardiasis in humans remain uncertain. Furthermore, due to the large amount of feces they produce, adult cattle may serve as important sources for G. duodenalis infections in young cattle, or other animals in the facility, despite relatively low numbers of cysts excreted per gram of feces. In contrast, the results of this study indicate that this herd posed a negligible risk of transmitting Cryptosporidium parvum infections to humans.

Giardia duodenalis infection and wastewater irrigation in Pakistan

The risk of Giardia duodenalis (Giardia) infection in farmers using untreated wastewater in agriculture was investigated in the city of Faisalabad, Pakistan, through a cross-sectional study. The study found a significantly increased risk of (asymptomatic) Giardia infection in wastewater farming households when compared with farming households using regular (non-wastewater) irrigation water (OR 3.3, 95% CI 2.5-4.4). Textile labourers who were employed in the city of Faisalabad but who lived in the same village as the wastewater farmers showed a risk of Giardia infection in between that of wastewater and non-wastewater farming households (OR 2.4, 95% CI 1.9-3.1). This study suggests that exposure to wastewater with high Giardia concentrations carries an increased risk for (asymptomatic) Giardia infection.

Giardia duodenalis and Cryptosporidium parvum infections in adult goats and their implications for neonatal kids

During the kidding season between January and April 2003, 10 farms were selected and divided into two groups of five. The farms in group A had had serious diarrhoeal illness...

Estimation of diagnostic test characteristics and prevalence of Giardia duodenalis in dairy calves in Belgium using a Bayesian approach

A Bayesian approach was used to determine both the test properties of three diagnostic test procedures and the prevalence of Giardia duodenalis in dairy calves in Belgium. A cross-sectional survey was conducted in the province of East Flanders, Belgium. Between September 2001 and December 2003, a total of 100 farms were visited and faecal samples were obtained rectally from 499 calves aged from newborn to 70 days. Because there is no gold standard for the diagnosis of a G. duodenalis infection in dairy calves, a subset of 235 samples obtained on the first 50 farms, was examined using three different assays: microscopical examination, an immunofluorescence assay (IFA) and an antigen detecting Elisa (ELISA). Based on the results of these three tests, Bayesian analysis indicated that the prevalence of G. duodenalis in dairy calves was 0.19 (95% Confidence Interval: 0.11–0.28) and that ELISA (Sensitivity (Se) 0.89 and Specificity (Sp): 0.90) and IFA (Se: 0.77 and Sp: 0.95) were both sensitive and specific diagnostic techniques, whereas microscopical examination was less sensitive (Se: 0.56 and Sp: 0.87). The proportion of positive farms was estimated as 0.42 (0.24–0.62). The prevalence and the cyst excretion in calves from different age categories were based on data obtained by IFA on all 499 samples. The prevalence was highest among four to five week old calves and remained high among older calves up to 10 weeks, but was lower among calves before the age of two weeks. The number of excreted cysts was estimated by IFA and ranged from 100 to 1,040,000 cysts per gram faeces, with a mean of 3516 cysts per gram faeces. The intensity of excretion peaked among four-week-old calves and remained high among calves up to the age of eight weeks. This is the first known study to use Bayesian analysis to estimate the prevalence of G. duodenalis in the faeces of dairy calves and to estimate test characteristics of diagnostic assays used for the detection of G. duodenalis.

Identificación de antígenos de aislamientos colombianos de Giardia duodenalis reconocidos por IgG total y subclases.

Antigen profiles were described for Giardia duodenalis cysts and trophozoites that are recognized by IgG and its anti-G. dudodenalis subclasses (IgG1, IgG2, IgG3, IgG4). Antigens were identified by Western blot from G. duodenalis cyst and trophozoite isolates. Cysts and trophozoites were each subjected to protein separation by SDS-PAGE. The proteins were then transferred to nitrocellulose membranes by electroimmunoblot, and their antigenicity was determined by exposing them to sera from patients with confirmed diagnosis of G. duodenalis infection. The antigen-antibody reaction was revealed by specific alkaline phosphatase antibody conjugates against IgG, IgG2, IgG3, IgG4: bands were visualized by addition of the substrate 5-bromo-4-chloro-3-indolyl-phosphate and the stain nitro blue tetrazolium. The bands were read and analyzed by linear regression using Quantity One software. Thirty two antigens were simultaneously recognized by total IgG anti-G. duodenalis in the cyst and trophozoite stages. The antigens varied in molecular weight from 22 to 185 kDa. Nineteen antigens were identified by both IgG, and IgG3 anti-G duodenalis, with molecular weights ranging from 42 to 180 kDa. IgG2 and IgG4 did not identify any antigen in either stage. The antigens of molecular weights 27, 30, 31, 33, 45, 49, 57, 78, 89 and 170 kDa are shared with G. duodenalis isolates from other geographical regions of Colombia. The recognition of cyst and trophozoite antigens of Colombian G. duodenalis isolates by IgG, IgG1 and IgG3 anti-G. duodenalis suggested that they are involved in the induction of the host immune response.

Identificación de antígenos de quistes y trofozoítos de aislamientos colombianos de Giardia duodenalis reconocidos por IgA.

Little is known about the role of IgA in the immune response against Giardia duodenalis infection. The current study identified the antigens of Colombian G. duodenalis isolates which stimulate the production of IgA anti-G. dudoenalis. Cyst and trophozoite stage proteins were separated by SDS-PAGE and their antigenicity was determined by Western blot. Without 2-mercapto ethanol (2-ME), the protein profile of the cyst stage showed 24 proteins within a molecular weight range of 23-270 kDa; with 2-ME, 35 polypeptides ranging from 22 to 241 kDa were distinguished. The trophozoite stage protein profile without 2-ME was formed by 16 proteins within the range of 24-270 kDa; with 2-ME, 45 proteins were present between 18 and 241 kDa. The identification of 20 and 29 antigens from the cyst and trophozoite stage, respectively, suggested that G. duodenalis stimulates a specific humoral immune response in the human host. The antigens of 31, 57, 110, 133, and 170 kDa recognized by anti-G duodenalis IgA in both cysts and trophozoites corresponded with G. duodenalis isolates from other geographic regions, whereas those of 35, 38, 43, 45, 49, 52, 60, 62, 65, 72, 82, 99, 145, 155, and 185 kDa seemed specific to Colombian isolates. This indicated that antigens of 57, 65, 145, and 170 kDa, recognized by anti-G. duodenalis IgA antibodies in cysts (with frequencies between 82% and 96%) and trophozoites (with frequencies between 86% and 97%) can be considered identification markers for G. duodenalis infections.

Passive immunity and serological immune response in dairy calves associated with natural Giardia duodenalis infections

In a previous study, Giardia infection patterns were studied in newborn dairy calves over a 4-month period. Chronic Giardia infections were observed in all calves with initial cyst excretion occurring at approximately 1 month of age. In the work presented here, the passive immunity and serological immune response associated with these Giardia infections were examined. Colostrum and milk samples were collected from the dams of these calves, and monthly serum samples were collected from each calf. The colostrum, milk and sera samples were analyzed by ELISA and Western blot for the presence of anti- Giardia IgG antibodies. In addition, the in vitro anti- Giardia activity of milk and colostrum was examined using a miniculture adherence assay. When examined by ELISA, mean anti- Giardia antibody titres were found to be significantly higher in colostrum compared to milk. The monthly mean serum antibody titres in the calves were not found to differ significantly at any time point during the study. Western blot analysis revealed that colostrum from the dams reacted strongly with many different Giardia antigens between 205 and 7.5 kDa, while milk reacted with few antigens in the same size range. Sera collected from the calves when 30 and 60 days of age reacted with few Giardia antigens, but as the calves aged, IgG antibodies in their sera began to react with antigens of 21, 50, 65, 73 and 79 kDa. The miniculture adherence assay demonstrated that colostrum had significantly more anti- Giardia activity in vitro compared to milk. These results suggest that the calves in this dairy did not mount a significant humoral immune response against Giardia following infection. However, colostrum contained a high level of anti- Giardia antibodies and exhibited anti- Giardia activity in vitro. Therefore, colostrum may have the potential to provide initial protection against Giardia infections in calves, but the lack of a strong, specific humoral immune response by these calves could account for the high prevalence and chronic duration of the infections.

Serodiagnóstico de giardiosis: identificación de inmunoglobulina G anti-Giardia duodenalis en suero mediante ELISA

Diagnosis of Giardia duodenalis infections is based upon identification of cysts or trophozoites in fecal samples. However, sensitivity of parasitological methods reaches a maximum of 85% in multiple samples, due to intermittent excretion of cysts. Presence of antibodies does not distinguish between a recent or a past infection, but they can aid in differential diagnosis. The aim of this study was to standardize and evaluate an immunoenzymatic assay (ELISA) for the detection of anti-Giardia duodenalis IgG antibodies in sera from infected patients. Antigen was prepared from cultured trophozoites initially obtained from the small intestine of gerbils (Meriones unguiculatus) that had been previously infected with cysts purified from positive human fecal samples. Sixty sera from patients with parasitologically demonstrated Giardia infection (positive samples) and 47 sera from umbilical cords (negative samples) were used to standardize and evaluate the test. Anti human IgG linked to alkaline phosphatase was used as conjugate. The optimum concentration of G. duodenalis trophozoite antigen was 15 ug/ml and the optimum dilutions of sera and conjugate were 1 :25 and 1 :400, respectively The cut-off value (absorbance) was 0.300. The pararneters of the test were: sensitivity, 98.3% (95% confidence interval (95%Cl): 89.9%-99.9%); specificity, 95.7% (95% CI: 84.3%-99.3%); positive predictive value, 96.7% (95% CI: 87.6% - 99.4%), and negative predictive value: 97.8% (95% GI: 87.0%-99.9%). The ELlSA test will improve the diagnosis of giardiasis and will be useful for epidemiological studies of seroprevalence.

Human giardiasis: genotype linked differences in clinical symptomatology

Giardia duodenalis infection in humans can cause a variety of clinical symptoms. The relation between clinical symptomatology and the Giardia isolate genotype was studied in 18 Dutch patients infected with G. duodenalis who visited their general practitioner. Contrary to earlier studies, a 100% correlation between severity of diarrhoeal complaints and genotype was found: assemblage A isolates were solely detected in patients with intermittent diarrhoeal complaints, while assemblage B isolates were present in patients with persistent diarrhoeal complaints. These results are significant because they show for the first time that genetically linked features of G. duodenalis are major determinants in the severity of infection in human giardiasis.

Prevalence and genotypic characterisation of Giardia in dairy calves from Western Australia and Western Canada

In this study, the prevalence of Giardia duodenalis infections was determined in Western Canadian and Western Australian dairy calves. Faecal samples were collected from Holstein calves located on a commercial dairy near Lethbridge, Alta., Canada ( N=28) and from calves located on two commercial dairies located near Perth, WA, Australia ( N=36). Faecal samples were examined for the presence of Giardia cysts using sucrose gradient centrifugation, followed by immunofluoresence microscopy. DNA was then extracted from Giardia isolates obtained from positive samples. A PCR based method was employed to amplify and sequence a 292 bp region of the 16S-rRNA gene. Genetic sequences obtained from Giardia isolates were compared to each other and to previously sequenced isolates. Following a single faecal sample, 58% of Western Australian calves and 57% of Western Canadian calves were positive for Giardia. Geometric mean cyst counts/g of faeces were 839 for Western Australian calves and 3475 for Western Canadian calves, but these values did not differ significantly. Genetic sequences were obtained from 10 calves from Western Canada, while six sequences were obtained from Western Australian calves. Of the Western Canadian isolates, eight aligned with the proposed ‘Hoofed livestock’ genotype. Of the five isolates obtained from Western Australian calves, four sequences were identical to the ‘Hoofed livestock’ genotype. Two isolates from the Western Canadian calves and one isolate from the Western Australian calves had the identical genetic sequence to the Genotype (Assemblage) A sequence, a common human genotype. The results of this study demonstrate, for the first time, that Giardia infections occur in Western Australian calves. Also, calves from different geographical locations appear to be primarily infected with a Giardia genotype unique to hoofed livestock. However, calves can shed Giardia cysts potentially infective for humans. Thus, Giardia infections should be considered important to Australian dairy producers, and infections in calves may pose a risk to public health regardless of geographical location.

Duration of naturally acquired giardiosis and cryptosporidiosis in dairy calves and their association with diarrhea

Objective To determine duration of infection and association of infection with diarrhea for dairy calves with naturally acquired cryptosporidiosis and giardiosis. Design Cohort study. Animals 20 Holstein calves on a single dairy farm. Procedure Fecal samples were collected 3 times/wk for the first 45 days after birth, then weekly until calves were 120 days old and examined for Giardia duodenalis cysts and Cryptosporidium parvum oocysts. Calves were monitored for diarrhea during the first 45 days after birth; during each episode of diarrhea, fecal samples were examined for parasitic, bacterial, and viral pathogens. Results All 20 calves shed Giardia cysts and Cryptosporidium oocysts at some time during the study. Mean ages at which Giardia cysts and Cryptosporidium oocysts were first detected were 31.5 and 16.3 days, respectively. Mean number of Giardia cysts in feces remained high throughout the study, whereas Cryptosporidium oocysts decreased to low or undetectable numbers 2 weeks after infection. Eighteen calves had a total of 38 episodes of diarrhea during the first 45 days after birth. Giardia duodenalis was the only pathogen identified during 6 (16%) episodes, C parvum was the only pathogen identified during 9 (24%) episodes, and G duodenalis and C parvum were identified together during 10 (26%) episodes. Conclusions Prevalences of giardiosis and cryptosporidiosis were high in these calves, and both parasites were associated with development of diarrhea. Cryptosporidium parvum was an important pathogen when calves were < 1 month old, but G duodenalis was more important when calves were older. Calves cleared C parvum infections within 2 weeks; however, G duodenalis infections became chronic in these calves. (J Am Vet Med Assoc 1999;214:391–396)

Giardiasis and cryptosporidiosis in day-care centers in the municipality Campinas SP

The prevalence of the Giardia duodenalis and Cryptosporidium parvum infections were studied in children 2-60 months old (n = 310) grouped to sex and age, enrolled in 8 day-care centers. Giardiasis was found in 42 (13.5%) of the children and, was most frequent in the age group corresponding to 19-24 months old although children at the first six months of life also presented positive faecal samples. Statistical analysis indicated no association between sex (p > 0.05) and prevalence for Giardia infection. C. parvum was detected in 20 (6.4%) of the children. Children seven to twelve months old showed the greatest prevalence of this parasite. There were not oocysts in the stools from the children 25-30 months and from those older than 36 months. Oocytes were detected in 4 children from the 0-6 months old group. There was no significative difference on sex (p = 0.09) and day-care-facility (p = 0.068) for C. parvum infection while age was associated with infection (p = 0.004). Epidemiological aspects were studied by familiar inquiry, by parasitological examinations of stools from the contact-members of each case and from animals present at the residence. Prevalence for C. parvum was higher when at least one of the parents was a professional in the Human Health Centers (73.6% positives), when there was report of concomitant disease (52.6% positives) and when diarrhoea was the main symptom at the collection of the faecal specimens (78.9% positives). Faecal examinations of the domestic animals were negatives for these two parasites.

An Increase in Giardia duodenalis Infection among Children Receiving Periodic Anthelmintic Treatment in Bangladesh

During a deworming study in northern Bangladesh, the prevalence of Giardia duodenalis increased significantly among three groups of children receiving periodic treatment with mebendazole. This was first observed in the treatment group (Group A) of a 12-month study. Giardia increased from 5 to 31 per cent in Group A (n = 49 chi 2 = 10.42, P < 0.005), but did not increase significantly in the placebo group (Group B) (11 to 18 per cent; chi 2 = 0.4, P = NS). The prevalence of Giardia in the treatment and placebo groups was not significantly different at the beginning of the study (n = 89, chi 2 = 0.8, P = NS). During a 6-month follow-up study, children in Groups A and B received 2-monthly treatment with mebendazole. Within 6 months the prevalence of Giardia increased significantly in Group B from 18 to 44 per cent (chi 2(1) = 6.14, P < 0.05). The prevalence of Giardia was also examined in 265 children at the end of an 18-month deworming study in the same area and found to be significantly higher among the treatment group (Group C) compared with the placebo group (Group D) (38 v. 21 per cent, chi 2 = 8.87, P < 0.005). Finally, the prevalence of Giardia was significantly higher in Group B after being treated than in Group D which had not been treated (44 and 21 per cent, respectively, chi 2 = 9.08, P < 0.005). These children were from the same villages and measured during the same month of the monsoon season.(ABSTRACT TRUNCATED AT 250 WORDS)

A Comparison of Methods for Extracting Amplifiable Giardia DNA from Various Environmental Samples

Human gastrointestinal illness due to Giardia duodenalis infection continues to be a public health problem. The ability to detect Giardia cysts is important in assessing the public health risk associated with environmental contamination. The low concentration of cysts in natural waters makes the use of the polymerase chain reaction (PCR) desirable in DNA probe-based detection methods. To date, amplification of DNA in environmental samples has been difficult to achieve. Humic compounds and/or other PCR inhibitors co-extract with nucleic acids, interfering with the polymerase reaction and lowering sensitivity. All of our attempts to separate humic compounds from DNA were unsuccessful. A substantial increase in the magnesium concentration in the reaction alleviated some of the inhibition, indicating that humics interfere by chelation of magnesium. PCR inhibition with environmental samples is most likely caused by a variety of contaminants.

Growth, activities of enzymes in the small intestine, and ultrastructure of microvillous border in gerbils infected withGiardia duodenalis

The aim of this study was to assess and correlate changes in weight gain, food intake, small intestinal disaccharidase activities and microvillous border surface area over the course of a primary Giardia duodenalis infection in weanling Mongolian gerbils (Meriones unguiculatus). Weight gain in infected animals was significantly impaired between days 8 and 20 postinoculation when compared to age- and weight-matched controls. No difference in food intake was observed between groups. Trophozoite population in the small intestine was maximal on day 4 and 6 of infection, and colonization persisted in the duodenum throughout the experiment (30 days). In infected gerbils, mucosal sucrase and maltase activities were significantly depressed in the duodenum and jejunum on day 4 and in all areas of the small intestine by day 6. Eight and 25 days postinoculation, disaccharidase activities had recovered in the jejunum and distal small intestine but remained depressed in the duodenum, the area where trophozoite colonization persisted. Diffuse loss of microvillous border surface area was observed in the duodenum and jejunum after 6 days of infection. Eight days postinoculation, microvillus surface area had returned to normal in the jejunum, but not in the duodenum. Our findings demonstrate that acute giardiasis in weanling gerbils impairs weight gain, depresses disaccharidase activities, and diffusely reduces mucosal microvillous border surface area.(ABSTRACT TRUNCATED AT 250 WORDS)

Ovarian Tumors with Endocrine Activity and Related Problems

Human infection with the protozoan parasite Giardia duodenalis is one the most common parasitic diseases worldwide. Higher incidence rates of giardiasis have been reported from human subjects with multiple debilitating chronic conditions, including hypogammaglobulinemia and common variable immunodeficiency (CVID). In the current study, stool specimens were collected from 199 individuals diagnosed with HIV or cancer and immunocompetent subjects. The sensitivity of microscopy-based detection on fresh stool preparations, trichrome staining and stool antigen immunodetection for the diagnosis of G. duodenalis were 36%, 45.5% and 100%, respectively when compared with a highly sensitive stool-based PCR method as the gold standard. Further multilocus molecular analyses using glutamate dehydrogenase (gdh) and triose phosphate isomerase (tpi) loci demonstrated that the AI genotype of G. duodenalis was the most prevalent, followed by the AII genotype and mixed (AI + B) infections. We concluded that stool antigen immunodetection-based immunoassays and stool-based PCR amplification had comparable sensitivity and specificity for the diagnosis of G. duodenalis infections in these populations. Stool antigen detection-based diagnostic modalities are rapid and accurate and may offer alternatives to conventional microscopy and PCR-based diagnostic methods for the diagnosis of G. duodenalis in human subjects living with HIV or cancer.