[Knowledge, perceptions and practice of dermatologists with respect to Giardia lamblia infection]

OBJECTIVE

to ascertain the level of knowledge, the perceptions and practice of dermatologists in the City of Havana with respect to Giardia lamblia infection.

METHODS

with prior informed consent given by the dermatologists from the City of Havana, 50 dermatologists- a number very close to the universe of these experts in the province- were administered a survey of their knowledge, perceptions and practice about this parasitosis. The survey was prepared in 4 phases; that is, interviews to physicians on diagnosis, treatment and control of giardiasis; drafting of a preliminary questionnaire based on the interview results; submission of this instruments to the experts, and finally its validation through its application to a small group of physicians.

RESULTS

it was evinced that the dermatologists in the City of Havana had poor knowledge about giardiasis, particularly its cutaneous manifestations (out of 19 questions on cognitive aspects, the correct answer mean was 10,18), inadequate perceptions on this disease and practice was not good.

CONCLUSIONS

with the aim of mitigating these difficulties, some academic intervention is needed to make emphasis on the formative aspects related to parasitic diseases in general and giardiasis in particular

Evaluation of a real-time polymerase chain reaction assay for the laboratory diagnosis of giardiasis

A real-time polymerase chain reaction (PCR) assay was evaluated in comparison with the combination of conventional methods (microscopic examination and antigen detection assay) during the period 2006 to 2008 on 771 fecal samples belonging to 386 patients to assess its usefulness for an accurate laboratory diagnosis of giardiasis. The real-time PCR assay detected Giardia intestinalis DNA in 195 samples (106 patients), including 26 samples (21 patients) negative by the conventional assays. Among the 21 patients, in 8 cases, giardiasis was previously diagnosed also by conventional methods in additional samples of the same patients, whereas in 13, it would have been undiagnosed if real-time PCR assay was not used. The real-time PCR assay demonstrated a detection limit of 2 cysts per reaction and 100% specificity and sensitivity compared to conventional methods. A genotype analysis targeting the beta-giardin gene allowed to identify 53 samples (23 patients) containing genotype A and 59 samples (45 patients) containing genotype B.

The comparison of the efficacy of various fixatives on diverse staining methods of Giardia lamblia cyst

The definite and exact diagnosis of protozoa is possible using high magnification objective lenses, provided that suitable stained smears are prepared. Therefore, the appropriateness of both fixative and staining methods to the species of parasite, which is the main objective of this study, is important. In this study, five various fixatives including (Merthiolate iodine formalin) MIF, (Sodium acetate-acetic acid formalin) SAF, (Polyvinyl alcohol) PVA, formalin and schaudinn and four types of stains including Hematoxylin I, Hematoxylin II, Trichrome and Carbol-fuchsin were prepared using standard procedures. After the smears of stool samples containing Giadria lamblia cyst were prepared and kept for 24 h in various fixatives, the study was carried out using the four above-mentioned stains by changing the ingredients and time as well as by repeating the experiments. After fixing and staining all the smears in identical conditions along with the implementing interferences in the staining process, the following results were eventually obtained considering the morphologic indexes and negative and positive scores (from 1 to 20): formalin with 17 scores in hematoxylin I staining, formalin and SAF with 15 and 14 scores, respectively in Hematoxylin II staining, MIF with 13 scores in Trichrome staining and SAF, PVA, MIF with 11.5, 11.5 and 11 scores, respectively in carbol-fuchsin staining were found to be the best fixatives. Hematoxylin I staining using formalin fixative with 17 scores showed the best result while the maximum score for Carbol-fuchsin staining was 11.5 showing a necessity for more expenditure, time and expert cooperation to reach ideal results.

Copro-antigen detection versus direct methods for the diagnosis of Giardia lamblia in patients from the National Liver Institute

In this study a commercially available immunoenzymatic assay to detect G. lamblia specific copro-antigen was evaluated. A total of 90 stool samples were tested. Diagnosis of giardiasis by ELISA for copro-Ag detection was positive in 46 (51.1%) patients whereas by direct stool analysis after formol ether concentration G. lamblia was detected in 38 (42.2%) patients only. ELISA technique for detection of Giardia copro-antigen had a sensitivity of 97.3% and a specificity of 82.6% with PPV of 80.4% and a NPV of 97.7%.

Transmission cycles of Giardia duodenalis in dogs and humans in Temple communities in Bangkok--a critical evaluation of its prevalence using three diagnostic tests in the field in the absence of a gold standard

The prevalence and associated risk factors for Giardia duodenalis in canine and human populations in Temple communities of Bangkok, Thailand were determined by evaluating three common diagnostic methods utilised to detect Giardia, namely zinc sulphate flotation and microscopy, an immunofluoresence antibody test and nested polymerase chain reaction (PCR) based on the SSU-rDNA gene. The diagnostic sensitivity and specificity together with the negative and positive predictive values of each test were evaluated in the absence of a gold standard using a Bayesian approach. The median estimates of the prevalence of infection with G. duodenalis in dogs and humans in Thailand were 56.8% (95% PCI, 30.4%, 77.7%) and 20.3% (95% PCI, 7.3%, 46.3%) respectively. PCR and immunofluorescence antibody tests (IFAT) were the most accurate tests overall with diagnostic sensitivity and specificity of 97.4% (95% PCI, 88.5%, 99.9%) and 56.2% (95% PCI, 40.4%, 82.9%) for the PCR and 61.8% (95% PCI, 40.8%, 99.1%) and 94.7% (95% PCI, 87.4%, 99.1%) for IFAT respectively Three cycles, anthroponotic, zoonotic and dog-specific cycles of G. duodenalis were shown to be operating among the human and canine populations in these Temple communities in Bangkok, supporting the role of the dog as a potential reservoir for Giardia infections in humans.

[Giardiasis as a rare disorder in differential diagnosis of abdominal pain]

The author is submitting a casuistry of the boy with nonspecific tummy ache.The cause of this illness was diagnosed as a paratrophic infection Giardia intestinalis. The author point sout it is necessary to have this seldom occurred children illness in consideration mainly in cases, when the doctor has a patient with nonspecific tummy ache and when these aches do not abate usual therapy or if there is a complication blond all understanding. As far as our patient is concerned it was cholecystitis discovered by ultrasound checkup which was done for nonspecific tummy ache. That is why it is necessary to have this illness in mind and mainly when there is a patient with nonspecific tummy ache and when the usual therapy does not work. In these cases the author recommends ultrasound tummy checkup and stercus checkup for parasites. The diagnostics consist in demonstratio of trophozoits or cystis in stercus. These days imunochromatografic test using ELISA method on the principles of detection with the help of monoclonal antibodies is preferred. The test is high sensitive and specific. The first choice medicine is metronidazol.

[Antigen detection methods in diagnosis of amebiasis, giardiasis and cryptosporidiosis]

Amebiasis is a significant health problem in developing countries. Humans are infected by two morphologically identical species of Entamoeba. Entamoeba histolytica causes amebic colitis and liver abscess, and Entamoeba dispar is noninvasive. Giardia intestinalis infection is seen worldwide and in all age groups. But giardiasis is especially prevalent in countries with poor sanitation and unsafe water, where it's responsible for most cases of childhood diarrhea. Cryptosporidium parvum, a protozoon, is an obligate intracellular parasite which can cause fatal diarrheal disease in immunocompromised individuals. Generally, the diagnosis of human intestinal protozoa depends on microscopic detection. Microscopic detection is inexpensive, but it is very labor-intensive and requires a skilled microscopist. Antigen detection methods (direct fluorescent antibody, enzyme immunoassay, and rapid, dipstick-like tests) can be performed quickly and do not require an experienced and skilled microscopist. Recently, commercially available diagnostic kits for the intestinal parasites E. histolytica, G.intestinalis and Cryptosporidium spp. use the laboratory diagnosis. In this review, we aimed to discuss the diagnosis of these three intestinal parasites using the antigen tests.

Giardia duodenalis assemblages associated with diarrhea in children in South India identified by PCR-RFLP

Giardial diarrhea in a birth cohort of 452 children in an urban slum in South India was characterized. Of the 155 episodes that occurred in 99 children, 73% were acute diarrhea. Children with better educated mothers and a toilet at home had lower odds of acquiring giardial diarrhea, whereas low socioeconomic status and drinking municipal water were associated with greater risk. Children with co-infections tended to have a slightly longer duration of diarrhea (P = 0.061) and showed significantly more wasting after an episode than children with diarrhea resulting from Giardia alone (P = 0.032). Among the 99 cases, 50 diarrheal and 51 asymptomatic Giardia positive samples were genotyped by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) at the triose phosphate isomerase gene. Assemblage B was predominant both in giardial diarrhea (80%) and asymptomatic giardiasis (94%). Children with Assemblage A subgroup-II alone or dual infections with both assemblage A and B had diarrhea more frequently (P = 0.07).

A single-step immunochromatographic lateral-flow assay for detection of Giardia lamblia and Cryptosporidium parvum antigens in human fecal samples

RIDA Quick immunochromatographic lateral-flow assay was evaluated for diagnosis of giardiasis and cryptosporidiosis as compared to the "gold standard" stool examination. Of the 300 specimens were examined by microscopy of direct wet films, concentrated sediments, modified trichrome and modified Ziehl-Neelsen stained slides, 35 samples of Giardia, ten Cryptosporidium, 35 of other parasites, and 20 negative controls were selected for RIDA Quick test examination. All the samples that gave discrepancy results were retested by the centrifugation prior to preparation for the permanent stained smear. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of RIDA quick test for Giardia were 91.6%, 98.4%, 97% & 95.4% respectively, while that of the microscopic stool examination were 94.5%, 100%, 100% & 96.9%. The sensitivity, specificity, PPV and NPV of RIDA quick test for Cryptosporidium was 91.6%, 100%, 100% & 98.8% respectively, while that of the microscopic stool examination were 83.3%, 100%, 100% & 97.7%.

[Investigation of the Giardia lamblia infection rate using whole gut lavage fluid]

BACKGROUND

Approximately 100 cases of giardiasis incidence are reported each year in Japan. The actual infection rate, however, is suspected to be higher since giardiasis is often overlooked due to the mildness of its symptoms. We investigated the presence of trophozoites of Giardia lamblia microscopically in sediment of whole gut lavage fluid obtained from patients undergoing colonoscopy.

METHODS

Whole gut lavage fluid was collected from all 3035 cases (2355 persons) undergoing colonoscopy at Osaka Medical Center for Cancer and Cardiovascular Diseases from 1993 to 1997. After Papanicolaou staining, sediment specimens of the lavage fluid were microscopically observed.

RESULTS

Giardia lamblia were identified in 15 cases (12 persons: 0.51%). Among them, four patients had diarrhea and/or abdominal pain. Subsequently, three of them were treated with metronidazole.

CONCLUSION

Giardiasis is not a rare infectious disease among the Japanese; therefore it should be taken into consideration in evaluating enteritis.

[Informative value of methods for laboratory diagnosis of Giardia infection]

The author assesses the informative value of two methods of laboratory diagnosis of L. intestinalis: serological assay using indirect immunofluorescence versus fecal Giardia antigen test using the immunochromatographic RIDA Quick Giardia test system. The results of these procedures were compared with those of fecal microscopy. The serological approach to diagnosing Giardia infection was found to be of low informative value. There is evidence suggesting the high specificity and sensitivity of detection of Giardia antibody in the feces, which allows it to be recommended in parasitological laboratory. It has been established that fecal prestorage in the Turdyev preservative can reduce the sensitivity of the RIDA Quick Giardia test system at the low concentration of parasitic cysts in the material being examined.

Use of a non-mercury containing fixative for diagnosis of giardiasis

In the present study, methanol was used instead of Schaudinn's fluid for preparation of permanently stained faecal smears. The efficacy of this method to detect Giardia lamblia trophozoites and cysts were compared to merthiolate iodine formalin (MIF) direct smear method and MIF concentration (MIFC) technique. Fresh faecal samples were collected from school students with gastrointestinal symptoms. In 50 Giardia positive faecal samples, trophozoites were detected alone in 9 samples and in association with cysts in 24 ones. A paired comparison of the frequency of detection of trophozoites and cysts by various methods was performed using McNemar statistical test. The results revealed that trichrome staining of methanol fixed smears was the most sensitive technique for trophozoite detection followed by MIF direct smear method (p < 0.05). For cysts, trichrome staining and MIFC had nearly equal sensitivity and were more sensitive than MIF direct smear method but with no statistically significant difference.

Prevalence and risk factors for giardiasis among primary school children in Damascus, Syria

OBJECTIVE

To evaluate the prevalence of giardiasis in primary school children in Damascus city and the countryside, and to investigate the possible risk factors for giardiasis infection.

METHODS

A cross-sectional study was carried out on school children from 23 primary schools in Damascus, between March and June 2006. Data were collected from 1469 children of both genders from urban and rural regions using structured questionnaires, anthropometric measurements, and laboratory analysis of fecal samples. The parasites were detected using a single-stool sample by direct wet examination under light microscope.

RESULTS

Two hundred and six (14%) of 1469 children were infected with Giardia lamblia, while 119 (8.1%) were found infected with other sorts of intestinal parasites. No correlation was found between giardiasis and age, gender, residence in urban or rural areas, availability of piped water or sewage system. In contrast, both mother's (p=0.003) and father's (p=0.018) levels of education, and the number of siblings in-home (p=0.014) were found significant predictors of giardiasis. As for children's nutritional status, 6.6% were found to have significant stunting, 1.8% had underweight, and 4.7% had wasting. Giardiasis, however, was not found a predictor of these conditions.

CONCLUSION

The Damascus region could be classified as medium-prevalence area for Giardia infections. Thus, the local administrators need to pay more attention to the prevention of parasitic infections along with improvement in education, environmental, and sanitary conditions.

Disease outbreak detection through clique covering on a weighted ICPC-coded graph

Even after a decade of increased research into the problem of detecting disease outbreaks, we lack a system that can limit the number of patients affected by a potential epidemic by recognising its existence at an early stage. In this paper we suggest the use of a weighted graph representing symptoms with an exceptionally high prevalence. Cliques with high weighted edges in such a graph will represent groups of symptoms that occur together more often than usual. As a result each clique will represent the main symptoms of a disease with a high incidence rate. This will make it easier to diagnose the nature of an outbreak, to reach the affected patients at an early stage and to distinguish between outbreaks occurring simultaneously.

Association of Helicobacter pylori and giardiasis in children with recurrent abdominal pain

The aim of this study was to examine the frequency and the relationship of H. pylori infection and giardiasis in children with recurrent abdominal pain. The study group included 98 patients and 88 healthy controls. Patients' sera were examined for anti-H. pylori specific IgG antibodies using H. pylori IgG ELISA. Analysis of stool samples was carried out by the H. pylori stool antigen (HpSA) enzyme immunoassay. For the diagnosis of giardiasis, all stool samples were examined by saline-Lugol and formalin-ethyl-acetate sedimentation methods. H. pylori was detected in 40 (49.0%) patients and 40 (45.5%) controls. G. intestinalis was detected in 30 (30.6%) patients and 18 (20.4%) controls. There was no significant difference in frequency between the groups in the distribution of H. pylori (p=0.6) and giardiasis (p=0.4). The frequency of the combination of H. pylori infection and giardiasis in the patient groups was 22.4% compared to 6.8% in the control groups and this result was statistically significant (p=0.002). It seems that the relationship of H. pylori infection and giardiasis represent an important ethiologic factor in children with recurrent abdominal pain.

Prevalence and associated risk factors for Giardia lamblia infection among children hospitalized for diarrhea in Goiânia, Goiás State, Brazil

The objective of this study was to determine the prevalence and to identify risk factors associated with Giardia lamblia infection in diarrheic children hospitalized for diarrhea in Goiânia, State of Goiás, Brazil. A cross-sectional study was conducted and a comprehensive questionnaire was administered to the child's primary custodian. Fixed effects logistic regression was used to determine the association between infection status for G. lamblia and host, sociodemographic, environmental and zoonotic risk factors. A total of 445 fecal samples were collected and processed by the DFA methodology, and G. lamblia cysts were present in the feces of 44 diarrheic children (9.9%). A variety of factors were found to be associated with giardiasis in these population: age of children (OR, 1.18; 90% CI, 1.0 - 1.36; p = 0.052), number of children in the household (OR 1.45; 90% CI, 1.13 - 1.86; p = 0.015), number of cats in the household (OR, 1.26; 90% CI, 1.03 -1.53; p = 0.059), food hygiene (OR, 2.9; 90% CI, 1.34 - 6.43; p = 0.024), day-care centers attendance (OR, 2.3; 90% CI, 1.20 - 4.36; p = 0.034), living on a rural farm within the past six months prior hospitalization (OR, 5.4; CI 90%, 1.5 - 20.1; p = 0.03) and the number of household adults (OR, 0.59; 90% CI, 0.42 - 0.83; p = 0.012). Such factors appropriately managed may help to reduce the annual incidence of this protozoal infection in the studied population.

Giardia lamblia and other intestinal parasitic infections and their relationships with nutritional status in children in Brazilian Amazon

The objective of this survey was to assess the relationships between intestinal parasitism, nutritional status and hemoglobin level in children with Indian ascendancy living in an urban area in Brazilian Amazon. We carried out a cross-sectional survey obtaining anthropometric, parasitological and socioeconomic data, and hemoglobin measurements of children aged six to 84 months. Anthropometric data were expressed as z-scores for weight for age (WAZ), height for age (HAZ), weight for height (WHZ) and mid upper circumference for age (MUACZ) parameters. Parasitological examinations were performed through Ritchie (n = 307), Kato-Katz (n = 278), Baermann-Moraes (n = 238) and Safranin-methylene blue methods (n = 307). Hemoglobin measurements were obtained with a Hemocue photometer (n = 282). Socioeconomic data were used in order to classify children in three family income strata (n = 242). Multiple linear regression analysis showed independent interactions between Giardia lamblia and WAZ (beta = -0.195, SE = 0.138, p = 0.003), WHZ (beta = -0.161, SE = 0.133, p = 0.018) and MUACZ (beta = -0.197, SE = 0.143, p = 0.011), controlling for age, sex, family income, Ascaris lumbricoides, and hookworm infection. Also, the multivariate model showed that the only variable associated with hemoglobin levels was age. Intestinal parasitism control should increase children's possibilities of full development in the studied area.