PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “GIARDIA”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1993

Comparison of Giardia lamblia and Giardia muris cyst inactivation by ozone.

Inactivation of Giardia lamblia and Giardia muris cysts was compared by using an ozone demand-free 0.05 M phosphate buffer in bench-scale batch reactors at 22 degrees C. Ozone was added to each trial from a concentrated stock solution for contact times of 2 and 5 min. The viability of the control and treated cysts was evaluated by using the C3H/HeN mouse and Mongolian gerbil models for G. muris and G. lamblia, respectively. The resistance of G. lamblia to ozone was not significantly different from that of G. muris under the study conditions, contrary to previously reported data that suggested G. lamblia was significantly more sensitive to ozone than G. muris was. The simple Ct value for 2 log unit inactivation of G. lamblia was 2.4 times higher than the Ct value recommended by the Surface Water Treatment Rule.

Animals↗
PubMed2004

Dietary lipids containing gangliosides reduce Giardia muris infection in vivo and survival of Giardia lamblia trophozoites in vitro.

We examined whether a ganglioside supplemented diet affected the course of Giardia muris infection in mice and survival of Giardia lamblia trophozoites in vitro. Female CD-1 mice were fed 1 of 5 experimental diets: standard lab chow as a control diet; semi-synthetic diets containing 20% (w/w) triglyceride based on the fat composition of a conventional infant formula; triglyceride diet; triglyceride diet containing a low level of ganglioside (0.1% w/w); and triglyceride diet containing a high level of ganglioside (1.0% w/w of diet). After 2 weeks of feeding, mice were inoculated with G. muris by gastric intubation and fed the experimental diets during the course of the infection. Cysts released in the faeces and trophozoites present in the small intestine were enumerated at various times post-infection. The average cyst output and the number of trophozoites during the course of the infection in mice fed ganglioside-containing diet were found to be significantly lower (3-log10 reduction) compared to animals fed control diets. The results of in vitro growth studies indicated that gangliosides may be directly toxic to the parasites. Thus, gangliosides have a protective effect against G. muris infection in vivo and affect the survival of G. lamblia trophozoites in vitro.

Animals↗
PubMed1988

Inactivation of Giardia lamblia and Giardia canis cysts by combined and free chlorine.

Free chlorine and a combined organic N-chloramine (3-chloro-4,4-dimethyl-2-oxazolidinone, compound 1) were compared for efficacy as disinfectants against an admixture of cysts of Giardia lamblia and Giardia canis in water solution under a variety of test conditions; variables were pH, temperature, and water quality. In general, compound 1 was found to reduce the giardial excystation in the solutions at lower concentration or shorter contact time at a given total chlorine concentration than did free chlorine.

Analysis of Variance↗
PubMed1985

Changes in intestinal fluid and mucosal immune responses to cholera toxin in Giardia muris infection and binding of cholera toxin to Giardia muris trophozoites.

The effect of Giardia muris infection on the diarrheal response and gut mucosal antibody response to cholera toxin was examined in mice. The results obtained showed that the fluid accumulation in intestinal loops exposed to cholera toxin was increased in mice infected with a low number (5 X 10(4) ) of G. muris cysts compared with the response in noninfected mice. This effect was associated with a marked reduction in absorption of oral rehydration fluid from the intestine. In contrast, mice infected with a high dose (2 X 10(5) ) of cysts showed a marked decrease in fluid accumulation in response to the toxin. This decrease might be related to the finding that both G. muris and Giardia lamblia trophozoites can bind significant amounts of cholera toxin. Evidence is presented which suggests that the gut mucosal antibody response, mainly immunoglobulin A but also immunoglobulin G, to an immunization course with perorally administered cholera toxin was depressed in mice infected with G. muris. The reduction in antibody levels was particularly evident when the primary immunization was made very early after infection. The serum antitoxin antibodies to the oral immunization with cholera toxin were, however, not affected. Likewise, the delayed-type hypersensitivity response against sheep erythrocytes in animals primed subcutaneously with sheep erythrocytes was not modified during the course of G. muris infection.

Animals↗
PubMed1981

Protection against infection with Giardia muris by milk containing antibody to Giardia.

Mice ingesting milk from immune mothers are protected against infection with Giardia muris. In order to be protected, the infant mice must be suckling immune milk at the time of challenge with the parasite and must continue to do so for at least three to five days thereafter. Suckling immune milk does not induce sustained immunity; infants become susceptible to infection after weaning begins at 14 days of age. Immune milk contains specific IgA and IgG antibody to Giardia, which may be the mediators of the demonstrated protection. The properties of this protection are similar to those described for protection against other enteric infections by milk.

Animal Population Groups↗
PubMed2002

PCR-RFLP analysis of Giardia intestinalis using a Giardia-specific gene, GLORF-C4.

A cDNA clone encoding GLORF-C4 was isolated from the WB strain, an assemblage A Giardia intestinalis. Interestingly, GLORF-C4 has been previously reported as an assemblage B-specific gene. Using two primers based on GLORF-C4 of the GS strain, a prototype assemblage B, GLORF-C4 gene was amplified from all the groups of G. intestinalis, and applied to detect the presence of cysts of G. intestinalis from faecal samples of cyst-passers. RFLP analysis of this PCR product successfully classified G. intestinalis into two distinct groups, assemblages A and B.

Animals↗
PubMed1989

A single-stranded RNA copy of the Giardia lamblia virus double-stranded RNA genome is present in the infected Giardia lamblia.

An isolate of Giardia lamblia infected with the double-stranded RNA virus (GLV) has two major species of RNA that are not present in an uninfected isolate. One of these species is the previously characterized double-stranded RNA genome of GLV (1). The second species of RNA appears to be a full length copy of one strand of the double-stranded RNA genome. This full length single-stranded RNA is not present in viral particles isolated from the growth medium. The cellular concentration of the single-stranded RNA changes during exponential and stationary phases of cell growth in a fashion consistent with a viral replicative intermediate or mRNA. The single-stranded species does not appear to be polyadenylated.

Animals↗
PubMed1987

Localization of acid phosphatase activity in Giardia lamblia and Giardia muris trophozoites.

Numerous membrane-bounded vacuoles are found adjacent to the plasma membrane of the pathogenic protozoan Giardia lamblia. The function of these vacuoles has been discussed by several authors. Approximately 100-400 nm in diameter with a core of low electron density, they have been suggested to be mitochondria, mucocysts, lysosomes, and endocytotic vacuoles. Enzyme cytochemical localization for acid phosphatase activity using cerium as a capturing agent demonstrates reaction product in these vacuoles as well as in the endoplasmic reticulum and nuclear envelope cisternae. The distribution of reaction product suggests the vacuoles are lysosome-like; however, their function and development remain in question.

Acid Phosphatase↗
PubMed1995

Comparison of conventional stool concentration and preserved-smear methods with Merifluor Cryptosporidium/Giardia Direct Immunofluorescence Assay and ProSpecT Giardia EZ Microplate Assay for detection of Giardia lamblia.

Giardiasis is the most common parasitic infection in the United States. Variation in the numbers of cysts and/or trophozoites that are present along with the need for a skilled microscopist offer challenges in diagnosis. We compared the sediment wet preparation and permanent stained smear results (concentration in formalin-ethyl acetate and preparation of a smear prepared from a polyvinyl alcohol-preserved specimen) from 512 consecutive specimens with the results obtained by using the Merifluor Cryptosporidium/Giardia Direct Immunofluorescence Assay (DFA; Meridian Diagnostics, Inc., Cincinnati, Ohio) and the ProSpecT Giardia EZ Microplate Assay (EIA; Alexon, Inc., Sunnyvale, Calif.). The Merifluor DFA detected 33 of 33 positive specimens, and the ProSpecT EIA detected 32 of 33 positive specimens. The diagnostic sensitivities of the Merifluor DFA and the ProSpecT EIA were 100 and 97%, respectively. The specificities of the assays were 99.8%. The Merifluor DFA and the ProSpecT EIA appear to be equally sensitive, and both are more sensitive than conventional microscopy.

Animals↗
PubMed1990

Transfection of the Giardia lamblia double-stranded RNA virus into giardia lamblia by electroporation of a single-stranded RNA copy of the viral genome.

The development of a genetic vector for protozoan parasites is a major hurdle yet to be crossed in the study of the molecular and cellular biology of these parasites. We have identified and isolated a double-stranded RNA virus (G. lamblia virus [GLV]) from certain strains of the intestinal parasitic protozoan Giardia lamblia (A. L. Wang and C. C. Wang, Mol. Biochem. Parasitol. 21:269-276, 1986), which is capable of infecting other virus-free strains of G. lamblia (R. L. Miller, A. L. Wang, and C. C. Wang, Exp. Parasitol. 66:118-123, 1988). Here we demonstrate that G. lamblia can be infected with GLV by electroporating uninfected cells with purified single-stranded RNA (E. S. Furfine, T. C. White, A. L. Wang, and C. C. Wang, Nucleic Acids Res. 17:7453-7467, 1989) representing a full-length copy of one strand of the GLV double-stranded RNA genome. To the best of our knowledge, this is the first demonstration in vivo that a single-stranded RNA is a competent replicative intermediate for this class of double-stranded RNA virus. In addition, this result represents the first long-term transfection of a protozoan by a single species of RNA and will hopefully expedite the development of GLV as a genetic transfecting vector.

Animals↗
PubMed2006

[Establishment of in vitro cultivation of Giardia canis trophozoites infected with Giardia canis virus].

OBJECTIVE: To cultivate a Giardia canis isolate with G. canis virus (GCV). METHODS: Five-day-old Meriones unguiculatus was infected with the cysts of G. canis isolated from dogs in Changchun and purified by sucrose density gradient centrifugation-G1 acid funnel filtration method. Trophozoites were isolated aseptically from the duodenum of the infected rodent after 8 days, then transferred to modified TYI-S-33 medium and cultivated at 37 degrees C. The trophozoites were centrifuged with 3,000 x g, 15 min after liquid nitrogen freeze-thawing three times and the supernatant stained negatively by phosphotungstic acid was observed with transmission electron microscope. RESULTS: G. canis trophozoites which adapted gradually to the environment and grew a cellular monolayer after 14 days were examined by freezing and thawing experiment, purity quotient, stability, biology characteristics and microbial contamination detection. The results demonstrated that a stable G. canis trophozoite cell isolate was established. G. canis virus with icosahedron spherical shape and 36 nm in diameter was observed by electron microscope. CONCLUSION: In vitro cultivation of G. canis trophozoites with GCV is established.

Animals↗
PubMed2003

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 7.5kDa, 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 79kDa. 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.

Animals↗
PubMed1987

Infectivity of Swiss Giardia isolates to jirds and mice, and in vitro cultivation of trophozoites originating from sheep.

The susceptibility of Giardia-free jirds (Meriones unguiculatus) and AJ-strain mice to oral inoculation with cysts from Swiss Giardia isolates was assessed. Giardia cysts of human, dog, cat, and sheep origin produced infections in jirds (4-10 weeks old). AJ-strain mice (6 weeks old) were insusceptible to Giardia from man, dog, and cat. The number of Giardia cysts inoculated per rodent ranged from 5000 to 12,600. The course of infection was studied in jirds experimentally infected with a Giardia isolate of cat origin. After administration of 6300 cysts to each of 16 jirds, 5 (31%) started to excrete cysts 4-5 days post inoculation (p.i.). Cyst excretion patterns were mostly intermittent, patency periods lasted 5-28 days, and average cyst numbers per g feces of individual jirds varied between 118,500 and 835,200 (maximal number: 3216700). The parasites were eliminated spontaneously in all 5 jirds. The Giardia isolate of cat origin was passaged 4 times in the jird. A Giardia isolate obtained from sheep was transferred in the cyst stage to jirds. Giardia trophozoites isolated from one of these jirds have been axenically cultivated in vitro in a modified, filter-sterilized TYI-S-33 culture medium and successfully cryopreserved. To our knowledge, this is the first report on axenic cultivation of Giardia of sheep origin. Giardia from cats could not be cultivated in vitro under the same conditions. The fact that Swiss Giardia isolates from humans and various domestic animals are not strictly host-specific is in agreement with similar findings from other areas and suggests a zoonotic character for giardiasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Secretory anti-Giardia lamblia antibodies in human milk: protective effect against diarrhea.

OBJECTIVE: To determine whether anti-Giardia lamblia secretory IgA (sIgA) antibodies in human milk protect infants from acquisition of or symptoms associated with Giardia infection. METHODS: One hundred ninety-seven Mexican mother/infant pairs were followed weekly from birth for diarrheal disease and feeding status. Infant stool specimens were collected weekly and were cultured for bacterial pathogens and tested for Giardia and rotavirus by enzyme-linked immunosorbent assay. Maternal milk samples were collected weekly for 1 month postpartum and monthly thereafter. To determine the protective effect of anti-Giardia sIgA in milk against infection and against diarrhea due to Giardia, milk samples from mothers of infected infants and appropriately matched controls were assayed for anti-Giardia sIgA by enzyme-linked immunosorbent assay. RESULTS: Asymptomatic, infected infants ingested significantly (P = .046) higher amounts of milk anti-Giardia sIgA compared with symptomatic, infected infants. However, milk anti-Giardia sIgA concentrations did not differ between Giardia-infected and noninfected infants. CONCLUSION: The amount of anti-Giardia sIgA in human milk was associated with prevention of symptoms of diarrhea due to Giardia, but not with acquisition of the organism.

Animals↗