Duodenalis Infection Research Articles

Prevalence and risk factors of Giardia duodenalis in domestic rabbbits (Oryctolagus cuniculus) in Jilin and Liaoning province, northeastern China.

Giardia duodenalis is one of the most important intestinal parasites that can infect virtually all animals, including rabbits and humans. However, there is little information regarding the prevalence and genotypes of G. duodenalis in domestic rabbits in China. A total of 426 rabbit fecal samples (136 from Shenyang City, 174 from Changchun City, and 116 from Jilin City) were examined by Lugol's iodine staining with microscopy analysis, and the positive samples were genotyped at the triosephosphate isomerase (tpi) and the beta giardin (bg) gene loci using nested PCR. Forty-two (9.86%) out of 426 rabbit fecal samples were G. duodenalis-positive under microscopy analysis, and the highest G. duodenalis infection rate was 23.08% on farm 6. The prevalence of G. duodenalis in rabbits from different cities ranged from 1.47% to 14.37%. Among different age groups, G. duodenalis prevalence in rabbits ranged from 5.41% to 12.58%. The prevalence of G. duodenalis in outdoor rabbits and indoor rabbits was 14.29% and 6.77%, respectively. In the present study, region and farming mode were highly correlated with G. duodenalis infection in rabbits. All 42 G. duodenalis isolates were successfully amplified and sequenced at the tpi and bg loci, and only G. duodenalis assemblage B were identified. This study not only further confirmed the dominance of G. duodenalis assemblage B in rabbits, but also further improved the foundation data concerning the distribution of G. duodenalis assemblages in China.

Molecular genotyping of Giardia duodenalis in children from Behbahan, southwestern Iran.

Giardia duodenalis is an intestinal flagellated protozoan that infects humans and several animal species. Giardiasis causing more than 200 million symptomatic infections globally is one of the most common causes of diarrhea in developing countries. Based on molecular studies mainly targeting the small-subunit (SSU) rRNA gene locus of the parasite, eight assemblages (A to H) have been identified in humans and other animal species. The aim of the current study was to evaluate the frequency and molecular diversity of G. duodenalis in children from rural and urban day care centers from Behbahan, southwestern Iran. This cross-sectional study was based on a concentration method for the microscopic detection of G. duodenalis in stool samples of 450 children, aged 1-7years, in Behbahan, southwestern Iran. The survey was conducted from December 2015 to May 2016. PCR methods targeting the SSU rRNA and triose phosphate isomerase (TPI) genes of G. duodenalis were used for the identification and genotyping of the parasite isolates. Based on sucrose flotation and microscopy techniques, 2.7% (12/450) of children were infected with G. duodenalis, of which six (50.0%) were males and the other six (50.0%) were females. Overall, 91.7% (11/12) of the infections were detected in children from rural areas. The SSU rRNA and TPI genes were amplified successfully in nine and eight, respectively, of the Giardia-positive samples at microscopy. Among the eight TPI sequences, assemblage A, sub-assemblage AII, was identified in five of the isolates. The sequences of the three remaining samples were untypable. Although no significantly statistical difference between genotype and clinical symptoms was found, five out of the eight isolates identified as assemblage A were obtained in asymptomatic children. Giardia duodenalis infections were more prevalent in children from rural day care schools, and the predominant assemblage was A, sub-assemblage AII. The higher prevalence of giardiasis in rural areas might be related to differences in personal hygiene habits, parents' education level, source of drinking water, and inadequate hygienic toilet facilities in rural areas.

Prevalence and multi-locus genotyping of Giardia duodenalis from goats in Shaanxi province, northwestern China

Giardia duodenalis (syn. Giardia lamblia, Giardia intestinalis) is an important zoonotic parasite that parasitizes the gastro-intestines of humans and animals, with diarrhea as the most common clinical symptom. The goat has been indicated as one of the most important reservoirs of G. duodenalis for humans. In the present study, we investigated the prevalence and genetic diversity of G. duodenalis in goats in Shaanxi province, northwestern China. A total of 1311 faecal specimens were examined, and the overall prevalence was 7.1% (93/1311). Although all the meat, cashmere and dairy goats were positive for infection, the highest prevalence was found in cashmere goats (10.2%), followed by dairy (9.4%) and meat goats (2.0%). Negative correlation between age and prevalence was also observed, and the highest prevalence was detected in 0–2-month goats. Genetic analysis showed the presence of three assemblages, including two zoonotic (A and B) and one animal-adapted assemblage E, with E as the prevalent assemblage found in all breeds of positive goats. The zoonotic assemblage A was found in Guanzhong dairy and Shanbei cashmere goats, but B was only detected in Boar goats. Additionally, mixed assemblages E and A were also identified in two cashmere goats. Multi-locus genotyping (MLST) using the gene loci of the triosephosphate isomerase (tpi), b-giardin (bg) and glutamate dehydrogenase (gdh) identified four novel multi-locus genotypes (MLGs), including two assemblage E MLGs and two assemblage A MLGs. These results suggested that Boar, Guanzhong dairy and Shanbei cashmere goats in Shaanxi province would be potential reservoirs for human infections in this area, and this study also provided basic data for controlling G. duodenalis infection in goats as well as other hosts.

Molecular epidemiology of Giardia duodenalis infection in humans in Southern Ethiopia: a triosephosphate isomerase gene-targeted analysis

BackgroundGiardia duodenalis is a species complex consisting of multiple genetically distinct assemblages. The species imposes a major public health crisis on developing countries. However, the molecular diversity, transmission dynamics and risk factors of the species in these countries are indeterminate. This study was conducted to determine the molecular epidemiology of G. duodenalis infection in asymptomatic individuals in Southern Ethiopia.MethodsFrom March to June 2014, fresh stool samples were collected from 590 randomly selected individuals. Socio-demographic data were gathered using a pre-tested structured questionnaire. The genotyping was done using triosephosphate isomerase gene-based nested polymerase chain reaction and DNA sequencing. The genetic identity and relatedness of isolates were determined using the basic local alignment search tool and phylogenetic analysis. Risk factors associated with G. duodenalis infection were analysed using binary and multinomial logistic regression models.ResultsThe results showed that 18.1% (92/509) of the study subjects were infected by G. duodenalis. Among the isolates, 35.9% (33/92) and 21.7% (20/92) were sub-typed into assemblages A and B, respectively, whereas 42.4% (39/92) showed mixed infections of A and B. Most of the assemblage A isolates (94%,31/33) were 100% identical to sequences registered in GenBank, of which the majority belonged to sub-assemblage AII. However, the high genetic variability and frequency of double peaks made sub-genotyping of assemblage B more problematic and only 20% (4/20) of the isolates matched 100% with the sequences. The risk factors of age (P = 0.032) and type of drinking water source (P = 0.003) both showed a significant association with the occurrence G. duodenalis infection.ConclusionsThis study established the endemicity of G. duodenalis in Southern Ethiopia. Infection with assemblage A was more frequent than with assemblage B, and the rate of infection was higher in children and in municipal/tap and open spring water consumers than the other groups. Sub-typing of assemblage B and determining the origin of double peaks were challenging. The present study confirms the need for further inclusive studies to be conducted focusing on sub-types of assemblage B and the origin of heterogeneity.

Bile Salt Hydrolase Activities: A Novel Target to Screen Anti-Giardia Lactobacilli?

Giardia duodenalis is a protozoan parasite responsible for giardiasis, a disease characterized by intestinal malabsorption, diarrhea and abdominal pain in a large number of mammal species. Giardiasis is one of the most common intestinal parasitic diseases in the world and thus a high veterinary, and public health concern. It is well-established that some probiotic bacteria may confer protection against this parasite in vitro and in vivo and we recently documented the implication of bile-salt hydrolase (BSH)-like activities from strain La1 of Lactobacillus johnsonii as mediators of these effects in vitro. We showed that these activities were able to generate deconjugated bile salts that were toxic to the parasite. In the present study, a wide collection of lactobacilli strains from different ecological origins was screened to assay their anti-giardial effects. Our results revealed that the anti-parasitic effects of some of the strains tested were well-correlated with the expression of BSH-like activities. The two most active strains in vitro, La1 and Lactobacillus gasseri CNCM I-4884, were then tested for their capacity to influence G. duodenalis infection in a suckling mice model. Strikingly, only L. gasseri CNCM I-4884 strain was able to significantly antagonize parasite growth with a dramatic reduction of the trophozoites load in the small intestine. Moreover, this strain also significantly reduced the fecal excretion of Giardia cysts after 5 days of treatment, which could contribute to blocking the transmission of the parasite, in contrast of La1 where no effect was observed. This study represents a step toward the development of new prophylactic strategies to combat G. duodenalis infection in both humans and animals.

Bile-Salt-Hydrolases from the Probiotic Strain Lactobacillus johnsonii La1 Mediate Anti-giardial Activity in Vitro and in Vivo

Giardia duodenalis (syn. G. lamblia, G. intestinalis) is the protozoan parasite responsible for giardiasis, the most common and widely spread intestinal parasitic disease worldwide, affecting both humans and animals. After cysts ingestion (through either contaminated food or water), Giardia excysts in the upper intestinal tract to release replicating trophozoites that are responsible for the production of symptoms. In the gut, Giardia cohabits with the host's microbiota, and several studies have revealed the importance of this gut ecosystem and/or some probiotic bacteria in providing protection against G. duodenalis infection through mechanisms that remain incompletely understood. Recent findings suggest that Bile-Salt-Hydrolase (BSH)-like activities from the probiotic strain of Lactobacillus johnsonii La1 may contribute to the anti-giardial activity displayed by this strain. Here, we cloned and expressed each of the three bsh genes present in the L. johnsonii La1 genome to study their enzymatic and biological properties. While BSH47 and BSH56 were expressed as recombinant active enzymes, no significant enzymatic activity was detected with BSH12. In vitro assays allowed determining the substrate specificities of both BSH47 and BSH56, which were different. Modeling of these BSHs indicated a strong conservation of their 3-D structures despite low conservation of their primary structures. Both recombinant enzymes were able to mediate anti-giardial biological activity against Giardia trophozoites in vitro. Moreover, BSH47 exerted significant anti-giardial effects when tested in a murine model of giardiasis. These results shed new light on the mechanism, whereby active BSH derived from the probiotic strain Lactobacillus johnsonii La1 may yield anti-giardial effects in vitro and in vivo. These findings pave the way toward novel approaches for the treatment of this widely spread but neglected infectious disease, both in human and in veterinary medicine.

Occurrence and molecular epidemiology of Giardia duodenalis infection in dog populations in eastern Spain

BackgroundGiardia duodenalis is one of the most common enteric parasites in domestic animals including dogs. Young animals are more prone to the infection, with clinical manifestations ranging from asymptomatic to acute or chronic diarrhoea. Dogs are primarily infected by canine-specific (C-D) assemblages of G. duodenalis. However, zoonotic assemblages A and B have been increasingly documented in canine isolates, raising the question of whether and to which extent dogs can act as natural reservoirs of human giardiosis.MethodsIn this cross-sectional epidemiological survey we assessed the molecular diversity of G. duodenalis in dogs in the province of Castellón, Eastern Spain. A total of 348 individual faecal samples from sheltered (n = 218), breeding (n = 24), hunting (n = 68), shepherd (n = 24), and pet (n = 14) dogs were collected between 2014 and 2016. Detection of G. duodenalis cysts in faecal material was carried out by direct fluorescence microscopy as a screening test, whereas a qPCR targeting the small subunit ribosomal RNA gene of the parasite was subsequently used as a confirmatory method.ResultsGiardia duodenalis was detected in 36.5% (95% CI: 31.6–41.7%) of dogs. No significant differences in prevalence rates could be demonstrated among dogs according to their sex and geographical origin, but breeding (45.8%; 95% CI: 27.9–64.9%) and sheltered (40.4%; 95% CI: 34.1–47.0%) dogs harboured significantly higher proportions of G. duodenalis. Multi-locus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of G. duodenalis allowed the characterization of 35 canine isolates that were unambiguously assigned to assemblages A (14.3%), B (22.9%), C (5.7%), and D (37.1%). A number of inter-assemblage mixed infections including A + B (11.4%), A + D (2.9%), and A + B + D (5.7%) were also identified.ConclusionsData presented here are strongly indicative of high infection pressures in kennelled animals. Zoonotic sub-assemblages AII, BIII, and BIV were responsible for a considerable proportion of the G. duodenalis infections detected, but very few of the genotypes identified have been previously documented in Spanish human populations. Although possible, zoonotic transmission between dogs and humans seems an infrequent event in this Spanish region.

Prevalence and risk factors associated with Giardia duodenalis infection in dairy cattle of Chitwan, Nepal

Livestock farming has been an integral part of Nepalese agriculture systems since time immemorial. Giardia duodenalis is a cosmopolitan intestinal parasite present in a wide range of hosts. Very little or no information is reported on the prevalence of giardiasis in livestock of Nepal. This study was done during Jan 18 to July 19, 2014 to determine the prevalence and associated risk factors of Giardia duodenalis infection in dairy cattle of Chitwan, Nepal. A total of 96 fresh fecal samples were collected from various dairy pocket areas and were transferred to collection bottles with 10% formalin. Wet smears of the samples were prepared, stained with lugol's iodine and then viewed under microscope at 400× magnification. The overall prevalence was found to be 44.79% (43/96). Based on the risk factors assessment survey, age was found to be significantly associated with the prevalence of Giardia duodenalis. The prevalence was found significantly (P<0.05) higher in 1-6 months age group compared to>3 years. Similarly, higher prevalence was found in diarrheic animals compared to their counterparts (P<0.05). Though higher prevalence was recorded in unhygienically housed animals, it was statistically non-significant (P<0.05). Giardiasis should be considered as an important cause of diarrhea and further advanced diagnostic approaches should be employed for the confirmation of giardiasis in dairy cattle.

Effectiveness and Tolerability of 3-Day Mebendazole Treatment of Giardia duodenalis Infection in Adults and Children: Two Prospective, Open-Label Phase IV Trials

BackgroundGiardia duodenalis is the most common intestinal pathogenic protozoan infection reported in humans. Both in vitro studies and 4 separate, sequential, comparative clinical trials conducted by our group in Cuba demonstrated mebendazole activity against G. duodenalis infection in both children and adults.ObjectiveThe 2 additional, prospective, open-label, Phase IV follow-up studies reported here were performed to further assess the effectiveness and safety profile of mebendazole in the outpatient treatment of G. duodenalis infection.MethodsAssenting children (n = 522) whose guardians gave permission and consenting adults (n = 423) diagnosed with G. duodenalis infection were given mebendazole (200 mg 3 times daily for 3 days). Medical histories and stool samples were obtained and physical/laboratory examinations were performed pretreatment then repeated on days 3, 5, and 7 after treatment completion. The evaluation of efficacy (ie, cure) was based on parasitologic response to therapy. Participants were considered cured, if no Giardia trophozoites or cysts were found in any of the 3 posttreatment fecal specimens evaluated by direct wet mounts and/or after Ritchie concentration techniques.ResultsNo participant refused to be enrolled and all returned for follow-up examinations. At the end of the treatment, stool samples were negative in 450 out of 522 children (86.2%) and 392 of 423 adults (92.7%). Treatment was well tolerated. In adults, the only adverse effect reported was abdominal pain (6.2%). Side effects reported in children included abdominal pain (5.6%), nausea (2.9%), and vomiting (2.3%). Reported side effects were all mild, transient, and self-limited and did not require discontinuation of treatment or additional medication.ConclusionsMebendazole may be an effective alternative treatment of G. duodenalis infections in both children and adults.

Prevalence and Molecular Characterization of Giardia duodenalis in Calves in Turkey

Background: Giardia duodenalis (G. duodenalis) is an ubiquitous, flagellated intestinal protozoan with major public health significance worldwide. Limited data are available on the epidemiology of G. duodenalis in dairy cattle from Turkey. Determining the zoonotic potential of the Giardia infection requires molecular characterization. The aim of the present study was to investigate the prevalence and to molecularly characterize G. duodenalis in calves less than three months of age in Aydin, Aegean region of Turkey.Materials, Methods &amp; Results: The study was conducted on different dairy farms in the south-western part of the Turkey, Aegean Region, Aydin. A total of 198 Holstein Friesian calves less than three months of age, of both sexes were enrolled into the study. Faecal samples from each calf were collected manually from the rectum using a disposable latex glove. The consistency of collected samples was recorded as diarrhoeic or non-diarrhoeic. Diagnosis of G. duodenalis infection was made microscopically by detection of cysts in the faecal samples. One hundred and sixteen (58.5%) of the 198 faecal samples were diarrheic. Giardia cysts were found in 27 (23.28%) of the diarrheic samples and in 8 (9.76%) of nondiarrheic samples (P &lt; 0.05). The overall prevalence of giardiosis in calves was determined as 17.67%. The prevalence of Giardia genotypes was identified by DNA sequence analysis of the beta-giardin gene for every PCR positive sample. The beta-giardin nested PCR assay was revealed assemblage A and sub-genotype A3 was detected in all of 35 samples (100%).Discussion: The highest prevalence of Giardia infection in calves is reported at the age between 1 and 6 months, and the prevalence shows decreased rate from the age of 6 months. The present study was conducted in Aydin, a province of south-western Turkey in the Aegean Region, and the overall prevalence from a total of 198 dairy calves was 17.67%. The prevalence rate in calves with diarrhoea was higher and reached up to 23.28%, whereas it was 9.76% in non-diarrhoeic calves. A prevalence study with molecular characterization of G. duodenalis isolates in cattle has not yet been reported from Turkey. Molecular studies have shown that mostly assemblage E predominates in cattle, but recent studies denoted that assemblage A is increasingly being detected and might be more widespread than expected before. In the present study, Giardia positive samples identified with a beta-giardin nested PCR assay. The sub-genotype A3 was identified in all samples. The same sub-genotype was identified in human and dog samples from different countries. Furthermore, sub-genotype A3 was found in humans and dogs from Turkey. In this context, results of the present study suggested an important role of calves as potential reservoirs of human infections in Turkey. In conclusion, epidemiological data revealed that G. duodenalis infection is frequent in calves with diarrhoea in Aydin, Turkey. The presence of the potentially zoonotic sub-genotype A3 and high prevalence of Giardia infection in diarrheic calves indicated the importance of treatment and necessary preventative measures. Further studies in human and animal populations living in this region are warranted regarding the zoonotic epidemiology of Giardia duodenalis.

Prevalence and molecular characterization of Giardia duodenalis in cattle and sheep from the Qinghai-Tibetan Plateau Area (QTPA), northwestern China

Giardia duodenalis is an important intestinal protozoan parasite with a wide range of hosts, including humans, livestock and wildlife. The purpose of this study was to determine the prevalence of G. duodenalis infections among cattle and sheep in the Qinghai-Tibetan Plateau Area (QTPA) and to assess the potential risk of the zoonotic transmission of this pathogen. A total of 454 stool specimens were collected and examined using the nested PCR method based on the G. duodenalis SSUrRNA gene fragment. Thirty-nine out of 389 cattle specimens examined were positive (10%) for the G. duodenalis infection. After the sequence analysis of the SSUrRNA gene, all detected G. duodenalis belong to assemblage E. No G. duodenalis infections were found in the 65 investigated samples from sheep. Our data therefore indicates that G. duodenalis is a common parasite in cattle in the QTPA, China and that cattle appear to be a reservoir of G. duodenalis for other animals and the environmental water supplies in the area.

Prevalence and associated risk factors of Giardia duodenalis infection among school-going children in Nepal.

This study aimed to determine the prevalence of intestinal parasites and its associated risk factors among school-going children in Kathmandu, Nepal. Between August and September 2016, a total of 333 stool samples were collected from children at five public schools. The collected samples were subjected to formol-ether concentration, followed by conventional microscopic examination for intestinal parasites. The overall prevalence of intestinal parasites was 24.3% (81/333), with Giardia spp. showing the highest prevalence of 18.9% (63/333). Samples positive for Giardia spp. by microscopy were further subjected to quantitative polymerase chain reaction (qPCR) for G. duodenalis, resulting in a positive ratio of 100%. The positive ratio of Giardia spp. was considerably high among children consuming tanker water (27.3%), jar water (21.0%), andtap water (17.5%). Our results demonstrated that G. duodenalis remains predominant in school-going children in Nepal.

Prevalence, genotyping and risk factors of Giardia duodenalis from dogs in Vietnam.

This study was carried out to determine the prevalence, genotypes/assemblages and possible risk factors associated with Giardia duodenalis infection in dogs in central Vietnam. A total of 209 dog fecal samples, randomly collected from private owned dogs (n=105) and dogs from stores (n=104), were examined for Giardia cysts by microscopy. Positive samples were genotyped by PCR-sequence analysis of β-giardin and triosephosphate isomerase genes markers. Risk factors were studied using a structured questionnaire and collected data were analyzed by univariate and multivariate logistic regression analyses. Results indicated that the overall infection rate was 8.6% (18/209) with the detected parasites were belonging to the non-zoonotic assemblages C and D. Age, gender and origin of animals were the main risk factors associated with G. duodenalis infection in dogs under study. Occurrence of infection was more likely in young animals compared to old ones and in females compared to males. Dogs originated from stores were more prone to Giardia infection compared to private owned counterparts.

Prevalence and multilocus genotyping of Giardia duodenalis in pigs of Shaanxi Province, northwestern China

BackgroundGiardiasis, caused by Giardia duodenalis (syn. Giardia intestinalis, Giardia lamblia), is a significant zoonotic parasitic disease of animals and humans worldwide. Accurate genotyping of G. duodenalis is essential for efficient control and management of giardiasis. The objectives of the present study were to investigate the prevalence and assemblages of giardiasis in pigs in Shaanxi Province, northwestern China, and for the first time study multilocus genotypes (MLGs) in pigs using multilocus genotyping technology in this region.ResultsOf 560 faecal samples collected from five farms in Shaanxi Province, 45 were positive for G. duodenalis and significant differences in prevalence were observed among different locations. Differences in prevalence were also detected in pigs of different age groups, with the highest prevalence in sows and the lowest in boars. Two assemblages, A and E, were identified, and a mixed infection of both A and E was identified in one faecal sample. Assemblage E was predominant and widely distributed in all investigated areas and age groups. Genetic viability was detected for both assemblages, and four different multi-locus genotypes (MLGs) within assemblage E were found, MLGE1-MLGE4.ConclusionsGiardia duodenalis was detected in pigs from Shaanxi Province, northwestern China, and genetic diversity was observed in these infections. Both assemblages A and E were detected, and four distinct MLGs within assemblage E were identified. These findings provide new data for controlling G. duodenalis infection in pigs.

Giardia duodenalis infection among rural communities in Yemen: A community-based assessment of the prevalence and associated risk factors

To investigate the prevalence and risk factors of Giardia infection among rural communities among rural communities in Yemen. In this cross-sectional study, a total of 605 stool samples were collected and screened for the presence of Giardia duodenalis (G.duodenalis) cysts and/or trophozoites by using three different diagnostic methods: direct smear, formalin-ether sedimentation, and trichrome staining. A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, behavioural and environmental characteristics of the participants. Overall, 28.1% (170/605) of the participants were infected by G.duodenalis. The prevalence was significantly higher among male participants compared to female (P=0.034); however, it was not significant among different age groups (P>0.05). Univariate and multivariate analyses identified four variables as the significant key risk factors of Giardia infection among the sampled communities. These are, in addition to being of the male gender, using unsafe water sources for drinking water, not washing hands after defecation, presence of other family members infected with Giardia, and close contact with domestic animals. The study reveals that Giardia infection is still prevalent among rural communities in Yemen. The provision of clean and safe drinking water, proper sanitation, and health education regarding personal hygiene practices, particularly handwashing, as well as identifying and treating infected family members is imperative and these interventions should be considered in a strategy to control intestinal parasites among these communities in order to curtail the transmission and morbidity caused by G.duodenalis.

Are species-specific antigen detection tests needed in the diagnosis of Giardia duodenalis infection?

Are species-specific antigen detection tests needed in the diagnosis of Giardia duodenalis infection?

Stool antigen immunodetection for diagnosis of Giardia duodenalis infection in human subjects with HIV and cancer

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.

Intestinal parasitic infections: Current status and associated risk factors among school aged children in an archetypal African urban slum in Nigeria.

Intestinal parasitic infections (IPIs) among school aged children (SAC) in Nigeria remains endemic, hence the need for regular surveillance to attract the attention of policy makers. This cross-sectional study investigated the current prevalence and factors associated with intestinal parasitic infections among school aged children in an urban slum of Lagos City, Nigeria. Single stool samples from 384 school aged children (188 boys and 196 girls) wereexamined by employing Merthiolate-iodine-formaldehyde concentration (MIFC) and Kato-Katz methods. Demographic characteristics and risk factors were obtained by questionnaires investigation. The overall prevalence was 86.2% in school children, out of them 39.1% had polyparasitism. IPIs showed the highest to the lowest prevalence of 62% (238/384), 25% (97/384), 12.3% (47/384), 11.8% (45/384), 9.9% (38/384), 8.4% (32/384), 3.4% (13/384), and 0.5% (2/384) found in Ascaris lumbricoides, Entamoeba histolytica/dispar, Giardia duodenalis, Endolimax nana, Entamoeba coli, Trichuris trichiura, Blastocystis hominis, and hookworm infections, respectively. MIFC technique showed superiority to Kato-Katz technique in the detection of IPIs (p<0.0001). Drinking untreated water was a significant risk factor for these school aged children in acquiring protozoan infections after multivariate adjustment (OR=1.86, 95% CI=1.08-3.20, p=0.02). Intestinal parasitic infections are very severe among school aged children in the urban slums, thus regular mass de-worming programs, health education, and the provision of safe drinking water is recommended to combat IPIs among the school aged children.

Molecular diversity and frequency of the diarrheagenic enteric protozoan Giardia duodenalis and Cryptosporidium spp. in a hospital setting in Northern Spain.

BackgroundHuman giardiosis and cryptosporidiosis are caused by the enteric protozoan parasites Giardia duodenalis and Cryptosporidium spp. Both pathogens are major contributors to the global burden of diarrhoeal disease, affecting primarily children and immunodebilitated individuals in resource-poor settings. Giardiosis and cryptosporidiosis also represent an important, often underestimate, public health threat in developed countries. In Spain only limited information is currently available on the epidemiology of these infections. Molecular data on the diversity, frequency, geographical distribution, and seasonality of G. duodenalis assemblages/sub-assemblages and Cryptosporidium species/sub-genotypes are particularly scarce.MethodsA longitudinal molecular epidemiological survey was conducted between July 2015 to September 2016 in patients referred to or attended at the Hospital San Pedro (La Rioja, Northern Spain) that tested positive for G. duodenalis (N = 106) or Cryptosporidium spp. (N = 103) by direct microscopy and/or a rapid lateral flow immunochromatographic assay. G. duodenalis infections were subsequently confirmed by real-time PCR and positive isolates assessed by multi-locus sequence genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Cryptosporidium species and sub-genotypes were investigated at the 60 kDa glycoprotein or the small subunit ribosomal RNA genes of the parasite. Sociodemographic and clinical parameters of infected patients were also gathered and analysed.Principal findingsOut of 90 G. duodenalis-positive isolates by real-time PCR a total of 16 isolates were successfully typed. AII (44%, 7/16) was the most prevalent sub-assemblage found, followed by BIV (31%, 5/16) and BIII (19%, 3/16). A discordant genotype result AII/AIII was identified in an additional (6%, 1/16) isolate. No mixed infections A+B were detected. Similarly, a total of 81 Cryptosporidium spp. isolates were successfully typed, revealing the presence of C. hominis (81%, 66/81) and C. parvum (19%, 15/81). Obtained GP60 sequences were assigned to sub-type families Ib (73%, 59/81) within C. hominis, and IIa (7%, 6/81) and IId (2%, 2/81) within C. parvum. A marked inter-annual variation in Cryptosporidium cases was observed.ConclusionsHuman giardiasis and cryptosporidiosis are commonly identified in patients seeking medical care in Northern Spain and represent a more important health concern than initially thought. Assemblage A within G. duodenalis and sub-genotype IbA10G2 within C. hominis were the genetic variants of these parasite species more frequently found circulating in the population under study. Molecular data presented here seem to suggest that G. duodenalis and Cryptosporidium infections arise through anthroponotic rather than zoonotic transmission in this Spanish region.

Molecular analysis of Giardia duodenalis isolates from symptomatic and asymptomatic children from La Habana, Cuba

Giardiasis is considered the most common intestinal parasitic disease in humans worldwide. In Cuba, this infection has particularly a strong clinical impact on the child population. Giardia duodenalis is a highly diverse protozoan, which comprises a complex of eight morphologically identical genetic assemblages, further divided into sub-assemblages. The present study used triose phosphate isomerase (tpi) and small-subunit ribosomal RNA (SSU rRNA) genes as genetic markers for the identification of G. duodenalis assemblages and sub-assemblages in correlation with clinical and epidemiological data in children attended at the Paediatric Hospital “William Soler” and at Pedro Kouri Institute, between 2015 and 2016. A prevalence of 8% of G. duodenalis infection was recorded in stool samples after concentration techniques from 68 children out of 847 analysed. A 100% detection of Giardia DNA was achieved by a SSU-rRNA PCR, whereas DNA from 63 of 68 (92.6%) was successfully amplified by tpi-PCR. By this assemblage-specific tpi-PCR 32 (50.8%) assemblage B, 17 (27.0%) assemblage A and 14 (22.2%) mixed infection (A+B) were identified. Assemblage B was significantly (P<0.02) more frequently found in children with diarrhoea. Sequence analysis of the tpi gene of Giardia isolates from symptomatic children showed that assemblage A belonged to the sub-assemblage AII, and 4 sub assemblages BIV and 1 sub assemblage BIII were also recorded. Only 2 discordant genotyping results were observed by phylogenetic comparison of SSU-rRNA and tpi sequences. Further studies with novel molecular tools for a better discrimination at the sub-assemblage level are needed to identify the dynamics of spread of giardiasis and to verify possible correlations between Giardia genetic diversity and clinical manifestation.