Real-time PCR/RFLP assay to detect Giardia intestinalis genotypes in human isolates with diarrhea in Egypt

Molecular epidemiology and multilocus genotyping of Giardia duodenalis in individuals attending major public hospitals in Shiraz, southwestern Iran: A public health concern

Giardia duodenalis is one of the most common causes of waterborne disease worldwide, and is often associated with outbreaks of diarrhea in areas with poor sanitation and hygiene. This study aimed to assess the prevalence and genetic diversity of G. duodenalis assemblages in individuals attending major public hospitals in Shiraz, southwestern Iran. From August 2022 to May 2023, a total of 614 stool samples from individuals were collected and initially examined for G. duodenalis cysts using parasitological techniques, sucrose flotation, and microscopy. Microscopy-positive samples were validated by SSU-PCR amplification of the parasite DNA. A multilocus genotyping (MLG) scheme, which focused on the triose phosphate isomerase (tpi) and the glutamate dehydrogenase (gdh) genes, was employed for genotyping purposes. G. duodenalis cysts were found in 7.5% (46/614) and 8.5% (52/614) of samples through microscopy and SSU-PCR, respectively. Successful amplification and sequencing results were obtained for 77.3% (17/22) and 45.5% (10/22) of the infected samples at the tpi and gdh loci, respectively. MLG data for the two loci were available for only five samples. Out of the 22 samples genotyped at any loci, 54.5% (12/22) were identified as assemblage A, while 45.5% (10/22) were identified as assemblage B. AII was the most predominant sub-assemblage identified [54.5% (12/22)], followed by BIII [27% (6/22)], discordant BIII/BIV [13.6% (3/22)], and BIV [4.5% (1/22)]. In the present study, no assemblages suited for non-human animal hosts (e.g., C-F) were detected. This suggests that the transmission of human giardiasis in Shiraz is primarily anthroponotic. Further molecular-based analyses are necessary to confirm and expand upon these findings. These analyses will also help determine the presence and public health importance of the parasite in environmental samples, such as drinking water.

Microscopy detection and molecular characterisation of Giardia duodenalis infection in outpatients seeking medical care in Egypt

Introduction

Giardiosis remains one of the most prevalent enteric parasitic infections globally. Earlier molecular-based studies conducted in Egypt have primarily focused on paediatric clinical populations and most were based on single genotyping markers. As a result, there is limited information on the frequency and genetic diversity of G. duodenalis infections in individuals of all age groups.

Methods

Individual stool samples (n = 460) from outpatients seeking medical care were collected during January-December 2021 in Kafr El-Sheikh governorate, northern Egypt. Initial screening for the presence of G. duodenalis was conducted by coprological examination. Microscopy-positive samples were further confirmed by real-time PCR. A multilocus sequence typing approach targeted amplification of the glutamate dehydrogenase (gdh), beta-giardin (bg), and triose phosphate isomerase (tpi) genes was used for genotyping purposes. A standardised epidemiological questionnaire was used to gather basic sociodemographic and clinical features of the recruited patients.

Results

Giardia duodenalis cysts were observed in 5.4% (25/460, 95% CI: 3.6-7.9) of the stool samples examined by conventional microscopy. The infection was more frequent in children under the age of 10 years and in individuals presenting with diarrhoea but without reaching statistical significance. Stool samples collected during the winter period were more likely to harbour G. duodenalis. All 25 microscopy-positive samples were confirmed by real-time PCR, but genotyping data was only available for 56.0% (14/25) of the isolates. Sequence analyses revealed the presence of assemblages A (78.6%, 11/14) and B (21.4%, 3/14). All assemblage A isolates were identified as sub-assemblage AII, whereas the three assemblage B sequences belonged to the sub-assemblage BIII. Patients with giardiosis presenting with diarrhoea were more frequently infected by the assemblage A of the parasite.

Conclusion

This is one of the largest epidemiological studies evaluating G. duodenalis infection in individuals of all age groups in Egypt. Our molecular data suggest that G. duodenalis infections in the surveyed population are primarily of anthropic origin. However, because assemblages A and B are zoonotic, some of the infections identified can have an animal origin. Additional investigations targeting animal (domestic and free-living) and environmental (water) samples are warranted to better understand the epidemiology of giardiosis in Egypt.

Assemblage characterization of Giardia duodenalis in South Khorasan province, eastern Iran, using HRM real-time PCR method

BACKGROUND

Giardia duodenalis is a common parasitic protozoan causing gastrointestinal illness in humans worldwide. The genetic diversity of G. duodenalis is reflected through the identification of different assemblages. In this study, we aimed to determine the assemblages of G. duodenalis in eastern Iran using nested-PCR and high-resolution melting (HRM) real-time PCR methods.

METHODS

A total of 58 positive G. duodenalis, which were isolated from 1800 subjects, referred to medical center laboratories in South Khorasan province, eastern Iran, from April 2020 to March 2022, were included in this study. DNA was extracted and HRM real-time PCR was performed for assemblage characterization.

RESULTS

HRM real-time PCR successfully characterized all samples. Accordingly, out of 58 positive samples, 53 (91.36%) and 5 (8.62%) were identified as assemblage A and B, respectively.

CONCLUSIONS

Our findings showed that HRM real-time PCR was able to characterize the assemblages of G. duodenalis. In addition, our results suggest high prevalence of assemblage A in eastern region of Iran.

Prevalence and molecular characterization of Giardia intestinalis isolated from children and calves in Babylon province, Iraq

Background and Aim

Giardia intestinalis is one of the most prevalent intestinal parasites in humans and animals, and children in close contact with livestock are particularly at risk of infection. This study aimed to detect assemblages of G. intestinalis and determine the origin of zoonotic transmission of Giardia in children and calves in different parts of Babylon province, Iraq.

Materials and Methods

One hundred stool samples from children (68 boys and 32 girls) and 100 fecal samples from calves (46 males and 54 females) of different ages were randomly collected. Molecular techniques were used to estimate the prevalence of G. intestinalis in children and calves. A nested polymerase chain reaction (PCR) was performed by targeting the triose phosphate isomerase gene in the samples to detect G. intestinalis assemblages.

Results

The overall rates of infection with G. intestinalis in children and calves were 21% and 34%, respectively, using the conventional microscopic method. The results illustrated that 61.90% (13/21) and 38.09% (8/21) of positive samples from children were allocated to assemblages A and B, respectively (p > 0.05). In calves, assemblages A and B were detecte in 82.35% (28/34) and 17.64% (6/34) of positive samples from calves, respectively (p ≤ 0.001). Ten PCR products were sequenced and submitted to the GenBank database. Phylogenetic analysis detected five human sequences each belonging to G. intestinalis assemblages A (OM850335-OM850339) and B (OM850340-OM850344). Similarly, five calf sequences each belonged to G. intestinalis assemblages A (ON75756-ON757660) and B (ON757661-ON757665).

Conclusion

The detection of large numbers of G. intestinalis assemblage A in both humans and cattle indicated that cattle could be a main source of zoonotic G. intestinalis infection in children in Babylon province, Iraq.

Gastrointestinal parasites in Africa: A review

Data on human gastrointestinal parasites (GIP) infections in the african sub-regions and countries are mainly lacking in terms of prevalence and population stratification by afflicted age group, symptomatology, multi-parasitism, and diagnostic methods. This study aims to describe the GIP reported in african countries and discuss the extent of the burden in the african context. Only 68.42% (39/57) of african countries reported human cases of GIP with helminths (45%, CI: 40-50%, I²: 99.79%) as the predominant parasitic group infecting the african population. On a regional scale, Central Africa had the highest pooled prevalence for GIP (43%, CI: 32-54%, I²: 99.74%), while the Central African Republic led all countries with a pooled prevalence of 90% (CI: 89-92%, I²: 99.96%). The vulnerable population (patients who are minorities, children, old, poor, underfunded, or have particular medical conditions) was the most affected (50%, CI: 37-62%, I²: 99.33%), with the predominance of GIP in the 6 to <20 years age group (48%, CI: 43-54%, I²: 99.68%). Reports on multi-parasitism (44%, CI: 40-48%, I²: 99.73%) were almost double the reports of single infections (43%, CI: 27-59%, I²: 99.77%) with combined molecular and non-molecular techniques demonstrating the best performance for GIP identification. The current review spans more than 40 years of GIP reports from the african continent. Geographical characteristics, environmental factors, habits of its inhabitants, and their health status play a crucial role in GIP modulation and behaviour in its captive hosts. Strategies for regular and enhanced surveillance, policy formation, and high-level community awareness are necessary to identify the true incidence in Africa and the transmission of the pathogens via water and food.

Multilocus sequence typing of Giardia duodenalis genotypes circulating in humans in a major metropolitan area

Giardia duodenalis is an intestinal protozoan parasite of humans and animal hosts and comprises eight microscopically indistinguishable molecularly-diverse lineages designated as assemblages A-H. Assemblages A and B are the primary sources of infections in humans and a wide range of mammals. Here, we identified assemblages, and inter-/intra-assemblage genetic diversity of human G. duodenalis isolates based on the multilocus sequence typing of the triosephosphate isomerase (tpi), β -giardin (bg), and glutamate dehydrogenase (gdh) loci. Multilocus sequence analysis of 62 microscopically-positive G. duodenalis fecal samples identified 26 (41.9%), 27 (43.5%), and nine (14.5%) isolates belonging to assemblages A, B, and discordant assemblages, respectively. The tpi locus assemblage-specific primers identified dual infections with A and B assemblages (45.2%). The sequence analysis of multiple alignments and phylogenetic analysis showed low genetic polymorphism in assemblage A isolates, classified as sub-assemblage AII at three loci, subtype A2 at tpi and gdh loci, and subtype A2 or A3 at bg locus. High genetic variations were found in assemblage B isolates with 14, 15, and 23 nucleotide patterns at tpi, bg, and gdh loci, respectively. Further concatenated sequence analysis revealed four multilocus genotypes (MLG) in 24 assemblages A isolates, two previously-identified (AII-1 and AII-5), with one novel multilocus genotype. However, the high genetic variations observed in assemblage B isolates among and within the three genetic loci prevented the definitive designation of specific MLGs for these isolates. Multilocus sequence typing may provide new insight into the genetic diversity of G. duodenalis isolates in Tehran, suggesting that humans are likely a potential source of G. duodenalis infection. Further host-specific experimental transmission studies are warranted to elucidate the modes of transmission within multiple host populations.

A review of the molecular epidemiology of Cryptosporidium spp. and Giardia duodenalis in the Middle East and North Africa (MENA) region

Cryptosporidium spp. and Giardia duodenalis are important protozoan parasites which are associated with diarrheal diseases in humans and animals worldwide. Relatively little is known about the molecular epidemiology of Cryptosporidium spp. and Giardia duodenalis in the Middle East Countries and North Africa (MENA region). Therefore, this review aimed to inspect published genotyping and subtyping studies on Cryptosporidium spp. and Giardia duodenalis in the MENA region. These studies indicate that both anthroponotic and zoonotic transmission of Cryptosporidium occurs with the predominance of zoonotic transmission in most countries. Seven Cryptosporidium species were identified in humans (C. parvum, C. hominis, Cryptosporidium meleagridis, C. felis, Cryptosporidium muris, C. canis and C. bovis), with C. parvum by far being the most prevalent species (reported in 95.4% of the retrieved studies). Among C. parvum gp60 subtype families, IIa and IId predominated, suggesting potential zoonotic transmission. However, in four MENA countries (Lebanon, Israel, Egypt and Tunisia), C. hominis was the predominant species with five subtype families reported including Ia, Ib, Id, If and Ie, all of which are usually anthroponotically transmitted between humans. In animals, the majority of studies were conducted mainly on livestock and poultry, 15 species were identified (C. parvum, C. hominis, C. muris, Cryptosporidium cuniculus, C. andersoni, C. bovis, C. meleagridis, C. baileyi, C. erinacei, C. ryanae, C. felis, C. suis, Cryptosporidium galli, C. xiaoi and C. ubiquitum) with C. parvum (IIa and IId subtypes) the dominant species in livestock and C. meleagridis and C. baileyi the dominant species in poultry. With G. duodenalis, five assemblages (A, B, C, E and F) were identified in humans and six (A, B, C, E, D and F) in animals in MENA countries with assemblages A and B commonly reported in humans, and assemblages A and E dominant in livestock. This review also identified a major knowledge gap in the lack of Cryptosporidium spp. and Giardia duodenalis typing studies in water and food sources in the MENA region. Of the few studies conducted on water sources (including drinking and tap water), ten Cryptosporidium species and four genotypes were identified, highlighting the potential role of water as the major route of Cryptosporidium spp. transmission in the region. In addition, three G. duodenalis assemblages (A, B and E) were detected in different water sources with AI, AII and BIV being the main sub-assemblages reported. More research is required in order to better understand the molecular diversity and transmission dynamics of Cryptsporidum spp. and Giardia duodenalis in humans, animals, water and food sources in MENA region.

Detection of Giardia intestinalis assemblages A and B among children from three villages in the West Delta region, Egypt using assemblage specific primers

Giardia intestinalis is a common diarrheagenic parasite infecting children globally. It has been classified into eight morphologically identical but genetically distinct genotypes. Human infection is mainly associated with A and B assemblages with variable geographical distribution. The present work aimed to study the epidemiology of assemblages A and B in children inhabiting different areas in Lower Egypt. Stool samples were collected from 315 children and examined microscopically for parasitic infections. Giardia positive samples were genotyped using tpi assemblage specific primers. The prevalence of Giardia was 18.1% among the examined children. Mixed assemblages A and B was more common (47.4%) than single assemblage B (36.8%) or A (15.8%). The distribution of different genotypes was significantly associated with the residence area, animal contact, and handwashing habits. A non-significant association was observed between Giardia assemblages and the clinical manifestations. Assemblage B is the predominant genotype among Egyptian children. The distribution of different Giardia assemblages is strongly associated with the studied area and the habits of its people.

Giardiasis in symptomatic children from Sharkia, Egypt: genetic assemblages and associated risk factors

Giardia intestinalis (G. intestinalis) is a common enteric protozoan parasite worldwide and in Egypt. Identification of true prevailing Giardia assemblages helps in identification of the sources of infection. The study's aim was to determine the true prevalence of Giardia assemblages in Egyptian children from Sharkia governorate presenting with gastrointestinal symptoms and to investigate their association with molecularly detected Giardia. A total of 617 stool specimens were collected from children presenting with gastrointestinal symptoms in Alquraeen, Sharkia governorate, Egypt for 17 months. All stool specimens were microscopically examined by wet mount smear before and after stool concentration to recover parasitic stages. Giardia copro-DNA was amplified from microscopically detected stool specimens using Copro-nPCR targeting the tpi gene for Giardia, followed by sequencing products of nPCR. The molecular prevalence of Giardia among symptomatic children was 9.88%, 83% of which were assemblage B and 17% were assemblages A. Giardia affected both sexes and all ages and was most prevalent in preschool children. Abdominal pain was the most common GIT symptom followed by diarrhoea. However, none of the patients' demographic variables (sex, age, weight and height) nor clinical symptoms showed significant association with molecular detection of Giardia. Giardia was common among symptomatic children from Sharkia, Egypt, with the predominance of assemblage B, which suggests the possibility of sharing common transmission source and route. Giardia had age, sex and clinical symptom distributions without statistical significance. The results necessitate further genomic studies targeting multiple gene targets for a better understanding of the ecology, dynamics of transmission, pathogenicity and clinical impact of Giardia infection, to improve its management and strategic control.

Genotyping of Giardia duodenalis in children in upper Egypt using assemblage- specific PCR technique

Giardia duodenalis is a common gastrointestinal protozoan parasite, causing diarrheal illness in humans worldwide. Yet, the distribution of G. duodenalis genotypes among human patients and their clinical relevance remains controversial. This study aimed to detect G. duodenalis in children in Upper Egypt and identify causative genotypes and elucidate a possible correlation between genotype and clinical presentation. One hundred sixty-five children, regardless of symptoms, were tested for giardiasis. Giardia positive stool samples (40/165) were subjected to PCR amplification targeting the tpi gene with positive PCR results in only 35 cases (87.5%). Assemblage-specific amplification of genotypes (A, B, and the zoonotic E strains) revealed predominantly G. duodenalis Assemblage A (45.7%). Assemblage B and mixed A and B infections were detected in 31.4% and 22.8% of children, respectively. Assemblage E was not detected. G. duodenalis assemblage A was dominant in children who complained of diarrhea and abdominal cramps. In contrast, asymptomatic children with positive stool samples display a higher frequency of assemblage B and mixed infections. The study highlights the predominance of Giardia Assemblage A in our study locality. This study is the first for this endemic area to use the copro-PCR technique for diagnosis and genotyping of giardiasis. Study results show the value of simple species-specific primers for genotyping in communities with little access to laboratory resources. Further genetic studies are needed to clarify the association between parasite genetic diversity and patient symptomatology.

Molecular Characterization of Giardia intestinalis Detected in Humans and Water Samples in Egypt

BACKGROUND

Giardia intestinalis is a common cause of gastrointestinal illness especially in children of developing countries. Giardia assemblages A and B are the major human infective genotypes.

OBJECTIVE

The present study aimed to investigate the role of water supply in the epidemiology of giardiasis via genotyping G. intestinalis detected in diarrheic children and in water samples in Egyptian rural areas.

METHODS

Stool samples of 100 diarrheic children, 40 drinking water samples and 10 raw water samples of canals were examined microscopically for Giardia. DNA was extracted from microscopically positive faecal samples and from all of the collected water samples. Amplification of Giardia tpi gene was performed by a nested PCR using assemblage A- and assemblage B-specific primers. Giardia gdh gene was amplified by a heminested PCR. Giardia genotypes were determined by restriction fragment polymorphism (RFLP) analysis of the amplified products. Sequencing of the amplified products was performed in two faecal and two water samples RESULTS: Giardia intestinalis was detected in 24 children, in none of the drinking water samples and in all canal water samples. Giardia sub-assemblage AII was identified in all stool and raw water samples. The RFLP pattern was confirmed in sequenced samples.

CONCLUSION

The presence of the same Giardia sub-assemblage in diarrheic children and in raw water samples shows by molecular evidence the potential for waterborne dissemination of Giardia in Egypt. Further studies are needed to monitor cyst levels and infectivity of the genotype detected in water for risk assessment and management.

Molecular and epidemiological characterization of Giardia Intestinalis assemblages detected in Djelfa, Algeria

Giardia intestinalis is a flagellated protozoan that lives and proliferates in the small intestine of the host causing giardiasis. The route of transmission is the fecal-oral route, either directly or indirectly. Limited genetic information on G. intestinalis is known in Algeria. This study aimed to estimate the prevalence of G. intestinalis assemblages in the city of Djelfa. A total of 355 fecal samples were collected from symptomatic and asymptomatic school children aged ranged between 6 and 11 years old. Genotyping was done to the Giardia positive samples (n = 30) targeting the beta-giardin gene by applying PCR/RFLP assay. Our data showed that most of the cases were asymptomatic (56.7%). Co-infection with other intestinal parasites was found in 16.6% of cases. We obtained 28/30 positive PCR products while two samples only showed false-negative results, and only 20 samples have shown strong PCR products suitable for RFLP analysis. Assemblage A (70%) was more prevalent than assemblage B (30%) and was more expressed by signs than assemblage B. Moreover, only assemblage A was associated with close contacts with domestic animals and birds. In conclusion, this study gave the first molecular data on G. intestinalis isolates in the city of Djelfa. Further expanded studies using more genes and covering other cities in Algeria are mostly needed.

Giardia lamblia assemblages A and B isolated from symptomatic and asymptomatic persons in Hamadan, west of Iran

Giardia is a very abundant organism bringing about diarrhoea in human beings. The focus of this analysis was the detection of Giardia lamblia assemblages in human stool specimens in Hamadan, west of Iran, as well as the association between obtained assemblages and clinical symptoms. Faecal samples of 4066 individuals admitted to the medical and health care facilities in Hamadan were inspected microscopically for the existence of Giardia cysts/trophozoites, and the clinical symptoms of the patients were recorded. The DNA of positive samples was isolated from and the nucleotide sequences of both glutamate dehydrogenase (gdh) (n = 15) and triose phosphate isomerase (tpi) (n = 8) genes were analyzed. In direct microscopy, a total of sixty-four samples (1.6%), were considered as positive for G. lamblia cysts or trophozoites. The sequence analysis showed that 18 out of 23 sequenced isolates (78.2%) were assemblage A and 5 (21.7%) were assemblage B. Clinical symptoms were observed in 44.4% and 40% of patients with assemblages A and B, respectively. Overall, the predominant assemblage A detected in the tested samples along with bioinformatics analysis suggest a potential zoonotic transmission in the region of the study. Although advanced analyses are necessary to understand the foundation and path of the infection, it seems that more sanitary regulations regarding contact with livestock and pet animals are essential.

A modified PCR-RFLP method to determine genetic diversity of Giardia lamblia human isolates based on triosephosphate isomerase (TPI) gene

An infection of digestive system, Giardiasis, caused by tiny parasites called Giardia lamblia (also known Giardia intestinalis or Giardia duodenalis). Giardia sp. is the most common intestinal parasite of humans and other animals throughout the world. Isolates of G. lamblia are classified into eight assemblages based on isoenzyme and DNA analyses. Assemblages A and B infect humans and a broad range of other hosts. The purpose of this study was to genotype human isolates of G. lamblia by PCR-RFLP in Karaj city. 60 positive fecal samples of G. lamblia were collected. DNA extraction and amplification of TPI gene were successfully conducted by nested-PCR. Subsequently, all samples were positive. Sequencing on 5 samples was conducted to determine genetic differences. The presence of 2 genotypes of G. lamblia (A and B) was revealed by the alignment of the TPI sequences obtained with reference sequences. The results of RFLP technique show that 35 of 60 (58.3%) isolates belonged to assemblage A, and 17 of 60 (28.3%) belonged to assemblage B but 1(1.7%) sample was not determined. Whereas, 7 (11.6%) specimens were detected as mixed infections. The latter RFLP was carried out to identify subtypes.The final results were 100% (35/35) AII, 82.3% (14/17) BIII, and 17.7% (3/17) BIV. This study suggests that the modified RFLP method is favorably time saving and easily achievable and highly economical. Hence, the sub-assemblage AII might be dominant in Karaj city.

First report on Giardia duodenalis assemblage F in Slovakian children living in poor environmental conditions

BACKGROUND

Giardiasis is one of the most common gastrointestinal infections of humans and animals attributable to complex of eight morphologically identical genetic assemblages, further divided into sub-assemblages. Disease is common for a wide range of hosts and genetic characterization is needed for better understanding of multifaceted epidemiology for this protozoan parasite. The aim of this study was to identify genetic heterogeneity in assemblages and sub-assemblages of Giardiaduodenalis circulating among the children population living in deprived socioeconomic conditions.

METHODS

A total of 333 stool samples from children in eastern Slovakia were collected during the period of 2015-2016 and analysed by molecular methods. Molecular characterization of G. duodenalis was performed by sequence analysis of triose phosphate isomerase gene (tpi) and glutamate dehydrogenase gene (gdh).

RESULTS

G. duodenalis DNA was detected in 21 samples (6.3%), out of which 14 isolates (66.7%) belonged to assemblage B, 4 isolates (19.0%) to sub-assemblage AII and 3 isolates (14.3%) corresponded to assemblage F. As regards the determination of sub-assemblages of assemblage B, 4 isolates were characterized as sub-assemblage BIII and 6 isolates as sub-assemblage BIV.

CONCLUSION

This study is the first finding of cat specific assemblage F in man not only in Slovakia, but also in Europe. The absence of molecular data about G. duodenalis in companion animals in Slovakia establishes a strong need for further investigation for potential sources of giardiasis and understanding the epidemiology will help to improve the preventive strategies in eradication of infection in this population.

Prevalence and molecular characterization of Strongyloides stercoralis, Giardia duodenalis, Cryptosporidium spp., and Blastocystis spp. isolates in school children in Cubal, Western Angola

BACKGROUND

Human infections by the gastrointestinal helminth Strongyloides stercoralis and the enteric protozoans Giardia duodenalis, Cryptosporidium spp. and Blastocystis spp. are not formally included in the list of 20 neglected tropical diseases prioritised by the World Health Organization. Although largely underdiagnosed and considered of lower public health relevance, these infections have been increasingly demonstrated to cause significant morbidity and even mortality globally, particularly among children living in resource-poor settings.

METHODS

In this cross-sectional survey the prevalence, frequency and molecular diversity of S. stercoralis, G. duodenalis, Cryptosporidium spp. and Blastocystis spp. were investigated in a school children population in the province of Benguela (Angola). A total of 351 stool samples were collected during January to June 2015. The presence of S. stercoralis and G. duodenalis was confirmed by qPCR methods. Giardia duodenalis assemblages and sub-assemblages were determined by multilocus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Detection and identification of Cryptosporidium and Blastocystis species and subtypes was carried out by amplification and sequencing of a partial fragment of the small-subunit ribosomal RNA gene of both protozoan. Analyses of risk factors potentially associated with the transmission of these pathogens were also conducted.

RESULTS

Prevalences of S. stercoralis, G. duodenalis, Cryptosporidium spp., and Blastocystis spp. were estimated at 21.4% (95% CI: 17.1-25.7%), 37.9% (95% CI: 32.8-43.0%), 2.9% (95% CI: 1.1-4.5%) and 25.6% (95% CI: 21.18-30.2%), respectively. Overall, 64.1% (225/351) of the children were infected by at least one of the pathogens investigated. Sequence analyses of the 28 G. duodenalis isolates that were successfully genotyped allowed the identification of sub-assemblages AI (14.3%), AII (14.3%), BIII (7.1%) and BIV (25.0%). Discordant typing results AII/AIII and BIII/BIV were identified in 7.1% and 14.3% of the isolates, respectively. A total of five additional isolates (17.9%) were identified as assemblage B. Three Cryptosporidium species including C. hominis (70%), C. parvum (20%) and C. canis (10%) were found circulating in the children population under study. A total of 75 Blastocystis isolates were assigned to the subtypes ST1 (30.7%), ST2 (30.7%), ST3 (36.0%), ST5 (1.3%) and ST7 (1.3%), respectively. Children younger than seven years of age had significantly higher risk of infections by protozoan enteropathogens (PRR: 1.35, P < 0.01), whereas being underweight seemed to have a protective effect against these infections (PRR: 0.74, P = 0.005).

CONCLUSIONS

The burden of disease attributable to human strongyloidiasis, giardiosis, cryptosporidiosis and blastocystosis in Angola is considerably higher than initially estimated in previous surveys. Surveillance and control of these infections should be jointly tackled with formally considered neglected tropical diseases in order to maximize effort and available resources. Our data also demonstrate the added value of using molecular diagnostic methods in high transmission areas.

A Comprehensive Review of Common Bacterial, Parasitic and Viral Zoonoses at the Human-Animal Interface in Egypt

Egypt has a unique geographical location connecting the three old-world continents Africa, Asia and Europe. It is the country with the highest population density in the Middle East, Northern Africa and the Mediterranean basin. This review summarizes the prevalence, reservoirs, sources of human infection and control regimes of common bacterial, parasitic and viral zoonoses in animals and humans in Egypt. There is a gap of knowledge conerning the epidemiology of zoonotic diseases at the human-animal interface in different localities in Egypt. Some zoonotic agents are “exotic” for Egypt (e.g., MERS-CoV and Crimean-Congo hemorrhagic fever virus), others are endemic (e.g., Brucellosis, Schistosomiasis and Avian influenza). Transboundary transmission of emerging pathogens from and to Egypt occurred via different routes, mainly importation/exportation of apparently healthy animals or migratory birds. Control of the infectious agents and multidrug resistant bacteria in the veterinary sector is on the frontline for infection control in humans. The implementation of control programs significantly decreased the prevalence of some zoonoses, such as schistosomiasis and fascioliasis, in some localities within the country. Sustainable awareness, education and training targeting groups at high risk (veterinarians, farmers, abattoir workers, nurses, etc.) are important to lessen the burden of zoonotic diseases among Egyptians. There is an urgent need for collaborative surveillance and intervention plans for the control of these diseases in Egypt.

Cryptosporidium and Giardia in Africa: current and future challenges

Cryptosporidium and Giardia are important causes of diarrhoeal illness. Adequate knowledge of the molecular diversity and geographical distribution of these parasites and the environmental and climatic variables that influence their prevalence is important for effective control of infection in at-risk populations, yet relatively little is known about the epidemiology of these parasites in Africa. Cryptosporidium is associated with moderate to severe diarrhoea and increased mortality in African countries and both parasites negatively affect child growth and development. Malnutrition and HIV status are also important contributors to the prevalence of Cryptosporidium and Giardia in African countries. Molecular typing of both parasites in humans, domestic animals and wildlife to date indicates a complex picture of both anthroponotic, zoonotic and spill-back transmission cycles that requires further investigation. For Cryptosporidium, the only available drug (nitazoxanide) is ineffective in HIV and malnourished individuals and therefore more effective drugs are a high priority. Several classes of drugs with good efficacy exist for Giardia, but dosing regimens are suboptimal and emerging resistance threatens clinical utility. Climate change and population growth are also predicted to increase both malnutrition and the prevalence of these parasites in water sources. Dedicated and co-ordinated commitments from African governments involving "One Health" initiatives with multidisciplinary teams of veterinarians, medical workers, relevant government authorities, and public health specialists working together are essential to control and prevent the burden of disease caused by these parasites.

Molecular Epidemiology of Giardia, Blastocystis and Cryptosporidium among Indigenous Children from the Colombian Amazon Basin

The incidence and prevalence of intestinal parasites in children is most likely due to lack of natural or acquired resistance and differences in behavior and habits closely related to environmental and socioeconomic determinants. The most important protozoa that parasitize humans are Giardia, Entamoeba, Blastocystis, and Cryptosporidium. These parasites present wide intraspecific genetic diversity and subsequently classified into assemblages and subtypes. The Amazon basin is the largest in the world and is the fifth freshwater reserve on the planet. Contradictorily, people living in these areas (Indigenous populations) have poor quality of life, which favors the infection of diseases of fecal-oral transmission. The aim of this work was to unravel the molecular epidemiology of Giardia, Blastocystis and Cryptosporidium across four communities (Puerto Nariño, San Juan del Soco, Villa Andrea and Nuevo Paraíso). We obtained 284 fecal samples from children under 15 years old that were analyzed by direct microscopy (261 samples) and Real Time PCR (qPCR) (284 samples). The positive samples for these protozoa were further characterized by several molecular markers to depict assemblages and subtypes. We observed a frequency of Giardia infection by microscopy of 23.7% (62 samples) and by qPCR of 64.8% (184 samples); for Blastocystis by microscopy of 35.2% (92 samples) and by qPCR of 88.7% (252 samples) and for Cryptosporidium only 1.9% (5 samples) were positive by microscopy and qPCR 1.8% (5 samples). Regarding the Giardia assemblages, using the glutamate dehydrogenase (gdh) marker we observed AI, BIII and BIV assemblages and when using triose phosphate isomerase (tpi) we observed assemblages AI, AII, BIII and BIV. In contrast, Blastocystis STs detected were 1, 2, 3, 4, and 6. Lastly, the species C. viatorum, C. hominis (with the subtypes IdA19 and IaA12R8) and C. parvum (with the subtype IIcA5G3c) were identified. We observed a high profile of zoonotic transmission regarding the Giardia assemblages and Blastocystis STs/alleles. Also, we highlight the elevated frequency of infection by these two protozoans suggesting an active transmission in the area. Our findings reinforces the need to deploy better epidemiological surveillance systems for enteric pathogens in the area.

Nested PCR targeting intergenic spacer (IGS) in genotyping of Giardia duodenalis isolated from symptomatic and asymptomatic infected Egyptian school children

Distinct sequences of Giardia duodenalis assemblages raised the hypothesis that certain assemblages may contribute to its clinical outcome. However, sequences analysis is time consuming, expensive, and needs many manual operations. Nested PCR targeting intergenic spacer (IGS) region was applied successfully to genotype G. duodenalis. This study aimed to identify the prevalence of G. duodenalis assemblages among giardiasis school children and its relation to the presence of symptoms using nested IGS/PCR. Of 65 microscopically confirmed Giardia-positive samples, 65 samples were genotyped proving high sensitivity (92.3%) of IGS/PCR. Negative IGS/PCR samples were also negative for β-giardin gene. Subassemblage AI was the commonest with 66.6% (20/30) among asymptomatic children compared to 53.3% (16/30) of symptomatic, while assemblage B was found in 40% (12/30) of symptomatic compared to 20% (6/30) of asymptomatic. The difference was significant. AII was only found in asymptomatic with 13.4% (4/30), while mixed infections (AI&B) were recorded only in 6.6% (2/30) of symptomatic group. A significant relation was found between younger children susceptibility for AI and B infections as presented in 77.7 (12/16) and 83.3% (10/12) of symptomatic, respectively, and 80 (16/80) and 33.4% (2/4) of asymptomatic, respectively. Significant relations were found between AI with intermittent diarrhea and B with chronic. A significant relation was found between assemblage distributions and heavy infection intensity. In conclusion, higher incidence of assemblage B among symptomatic children compared to asymptomatic could denote its possible pathogenic potential.

Prevalence of Giardia duodenalis assemblages and sub-assemblages in symptomatic patients from Damascus city and its suburbs

Giardia duodenalis is one of the most important human enteric parasites worldwide and is endemic throughout the world with a vast range of mammalian hosts. However, there is limited information on the prevalent genetic variability of G. duodenalis in Syria. This study aimed to evaluate the predominance of G. duodenalis assemblages/sub-assemblages causing humans infection in the city of Damascus and its suburbs. 40 symptomatic giardiasis patients were recruited in this study. Fecal samples were genotyped using PCR/RFLP assay targeting the β-giardin and glutamate dehydrogenase (gdh) genes. HaeIII, BspL1 and RsaI restriction enzymes were used to differentiate between G. duodenalis assemblages/sub-assemblages. Our data showed that 65% of isolates were of assemblage A; 45% belonged to sub-assemblage AII and 20% to sub-assemblage AI. Assemblage B was detected in 27.5% of isolates; 12.5% fit in sub-assemblage BIV, 5% fit in sub-assemblage BIII and 10.5% fit in Discordant genotype BIII/BIV. Mixed genotypes (AII+BIII and AI+BIV) were identified in 3 isolates (7.5%). Significant correlation was found between Giardia AII sub-assemblage and weight loss symptom (P-value=0.05) as well as between contact with domestic animals (cats, P-value=0.027). Moreover, a significant correlation was found between sub-assemblage AI and livestock breeding (P-value=0.000). In conclusion genotyping of human Giardia duodenalis isolates suggests anthroponotic transmission for the route of infection in Damascus and its suburbs. Further studies are needed to screen a wide geographic areas in Syria and to estimate the prevalence of G. duodenalis infection in our population.

Multilocus sequence analysis of Giardia spp. isolated from patients with diarrhea in Austria

Giardia duodenalis is a protozoan parasite causing intestinal infections in a wide range of mammals. Two distinct assemblages, A and B, infect humans predominantly; however, both are believed to be generally zoonotic. Giardia strains associated with infections in Austria have not been investigated at the molecular level. In this study, 65 human stool samples microscopically positive for Giardia spp. were subjected to DNA isolation and nested PCR targeting fragments of the glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi), and beta-gardin (bg) genes. A total of 52 samples were successfully analyzed using PCR and DNA sequencing. Assemblage B was detected most frequently and accounted for 65.4% (34/52) of infections, while Assemblage A accounted for 34.6% (18/52). There was a high level of genetic diversity among the isolates with 46.2% designated as sub-assemblage BIV (24/52), 25% sub-assemblage AII (13/52), 19.2% sub-assemblage BIII (10/52), and 9.6% sub-assemblage AI (5/52). No mixed infections were detected. The results suggest that the majority of infections were imported and that endemic anthroponotic transmission plays a minor role in Austria.

Frequency, diagnostic performance of coproantigen detection and genotyping of the Giardia among patients referred to a multi-level teaching hospital in northern India

Giardiasis, a common gastrointestinal parasitic infection in tropics, is diagnosed on stool microscopy (gold standard); however, its sensitivity is low due to intermittent fecal shedding. Coproantigen detection (ELISA) is useful but requires further evaluation. We aimed to study: (a) detection of Giardia by stool microscopy and/or coproantigen, (b) diagnostic performance of fecal antigen detection and microscopy, and c) genotypic characterization of G. lamblia using PCR specific for triose phosphate isomerase (tpi) gene. Stool samples from 2992 patients were examined by microscopy from March 2013 to March 2015 in a multi level teaching hospital in northern India. Giardia coproantigen detection was performed by ELISA in a subset of patients. Genetic characterization of G. lamblia was performed by PCR targeting tpi gene in a subset of microscopy positive stool samples. Of 2992 patients, 132 (4.4%) had Giardia by microscopy (cyst/trophozoite) and/or ELISA. ELISA was performed in 264 patients; of them, 127 were positive by microscopy. Sensitivity, specificity, positive and negative predictive values of ELISA were 91, 91, 94, and 91%, respectively, using microscopy as a gold standard. PCR was performed in 116 randomly selected samples having Giardia using tpi gene. Assemblages A and B were found among 44 (38%) and 72 (62%) patients, respectively. Assemblage B was more often associated with malnutrition and loss of appetite than A (48/72 [67%] vs. 21/44 [48%], P = 0.044 and 17/72 [24%] vs. 14/44 [32%], P = 0.019). We conclude that 4.4% of studied population had giardiasis. Fecal antigen is a useful method for diagnosis and assemblage B is the most common genotype.

Multilocus genotyping of Giardia duodenalis isolates from children in Oromia Special Zone, central Ethiopia

BACKGROUND

Giardia duodenalis is the etiologic agent of giardiasis in humans and other mammals worldwide. The burden of disease is high among children in developing countries where sanitation is inadequate. However, the epidemiology and genetic diversity of this parasite is poorly understood in Ethiopia. This study aimed to determine the prevalence and genetic diversity of G. duodenalis in asymptomatic children in Oromia Special Zone, central Ethiopia.

RESULTS

A total of 286 fresh fecal specimens were collected from children and screened using microscopy and PCR. The prevalence of Giardia duodenalis was 10.8 % (31/286) and 16.8 % (48/286) as detected by microscopy and nested PCR, respectively. The infection rate by the study area, sex and age group difference was not significant (P > 0.05). Genotyping results showed that 22.9 % (11/48) of the isolates belonged to assemblage A while 77.1 % (37/48) belonged to assemblage B. Although double peaks were observed at the chromatogram level, no mixed assemblage or sub-assemblage infections were demonstrated. Isolates of assemblage A mostly belonged to the sub-assemblage AII and showed similarity with previously described isolates. However, there was great genetic variability within assemblage B that showed heterogeneous nucleotide positions. Fifteen of them were new genotypes: 5 at the triose phosphate isomerase (tpi), 2 at the β-giardin (bg), and 8 at the glutamate dehydrogenase (gdh) genes.

CONCLUSIONS

Giardia duodenalis mainly assemblage B infection was predominant among the asymptomatic children in the study area. The high polymorphism found in isolates of assemblage B warrants a more defining tool to discriminate assemblage B at the sub-assemblage level. The findings of the present study indicate that there is a need to carry out national screening programs aiming to detect asymptomatic infections to minimize the reservoir of the disease.

First genetic characterisation of Giardia in human isolates from Jordan

Little is known about the epidemiology of Giardia in Jordan and to date, no genotyping studies have been conducted on Giardia isolates from Jordanians. In the present study, a total of 49 microscopy-positive faecal samples from Jordanian patients suffering from giardiasis were analysed at two loci: the triose phosphate isomerase (tpi) gene and the glutamate dehydrogenase (gdh) gene. At the tpi locus, a total of 28 samples amplified and assemblage A was identified in 46.4 % (13/28) samples, while assemblage B was identified in 50 % (14/28) samples and a mixed assemblage A and B was identified in one sample (3.6 %) (Table 1). At the gdh locus 48 isolates amplified and of these assemblages A was identified in 43.7 % (21/48) of isolates and assemblage B in 56.3 % (27/48) of isolates. No mixed infections were detected at the gdh locus. Subtyping at the gdh locus identified sub-assemblage AII in 43.7 % (21/48) of isolates and sub-assemblages BIII and BIV in 25 % (12/48) and 31.2 % (15/48) of isolates, respectively, with more genetic diversity in AII isolates than BIII or BIV isolates. Novel sub-types within each sub-assemblage were identified suggesting unique endemicity and anthroponotic transmission of Giardia in Jordanian patients suffering from giardiasis. Further studies are required to better understand the epidemiology and transmission of Giardia in Jordan.

Giardia duodenalis in Damascus, Syria: Identification of Giardia genotypes in a sample of human fecal isolates using polymerase chain reaction and restriction fragment length polymorphism analyzing method

Giardia duodenalis is a common gastrointestinal parasite that infects humans and many other mammals. It is most prevalent in many developing and industrialized countries. G. duodenalis is considered to be a complex species. While no morphological distinction among different assemblages exist, it can be genetically differentiated into eight major assemblages: A to H. The aim of this study was to determine the genetic heterogeneity of G. duodenalis in human isolates (a study conducted for the first time in Syria). 40 fecal samples were collected from three different hospitals during the hot summer season of 2014. Extraction of genomic DNA from all Giardia positive samples (based on a microscopic examination) was performed using QIAamp DNA Stool Mini Kit. β-giardin gene was used to differentiate between different Giardia assemblages. The 514 bp fragment was amplified using the Polymerase Chain Reaction method, followed by digestion in HaeIII restriction enzyme. Our result showed that genotype A was more frequent than genotype B, 27/40 (67.5%); 4/40 (10%) respectively. A mixed genotype of A+B was only detected in 9 isolates (22.5%). This is the first molecular study performed on G. duodenalis isolates in Syria in order to discriminate among the different genotypes. Further expanded studies using more genes are needed to detect and identify the Giardia parasite at the level of assemblage and sub-assemblage.

Predominance of Giardia lamblia assemblage A among iron deficiency anaemic pre-school Egyptian children

Intestinal parasites and nutritional deficiency can coexist and influence each other. This study aimed to clarify the association between Giardia genotypes and presence of iron deficiency anaemia (IDA) among pre-school Egyptian children. Two groups (IDA and non-anaemic) of giardiasis children (44/group) were selected according to their recovery response after treatment of giardiasis. Each group included 24 and 20 gastrointestinal symptomatic and asymptomatic, respectively. Giardia human genotypes were performed by intergenic spacer (IGS) gene based polymerase chain reaction (PCR) with high-resolution melting curve (HRM). PCR/HRM proved that Tms of assemblage A and B ranged from 79.31 ± 0.29 to 84.77 ± 0.31. In IDA patients, assemblages A and B were found among 40/44 (90.9 %) and 4/44 (9.1 %), respectively, while in non-anaemic patients, assemblages A and B were found in 10/44 (22.7 %) and 32/44 (72.7 %), respectively, beside two (4.6 %) cases had mixed infection. The difference was statistically significant. No significant relation was found between symptomatic or asymptomatic assemblages and IDA as assemblage A was found in 21/24 (87.5 %) and 19/20 (95 %) of symptomatic and asymptomatic, respectively, while 3/24 (12.5 %) and 1/20 (5 %) of assemblage B were symptomatic was asymptomatic, respectively. A significant relation was found between assemblage A subtypes distribution among IDA patients as AI and AII were detected on 23 (52.3 %) and 16 (36.4 %) of patients, respectively, while one case (2.3 %) had mixed infection. In conclusion, assemblage A is predominant among IDA giardiasis children suggesting its role in enhancing the occurrence of IDA while B has a protective role.

Risk Factors Associated with Parasitic Infection Among Municipality Solid-Waste Workers in an Egyptian Community

Solid-waste management is associated with several health hazards, particularly parasitic infection. The objective of the study was to determine the association between risk factors and the occurrence of intestinal parasitic infections (potentially pathogenic) among municipal waste collectors in Alexandria, Egypt. A cross-sectional survey was conducted in the main municipality company in Alexandria. A total of 346 municipality solid-waste workers (MSWWs) was interviewed using an in-depth questionnaire. The type of parasitic infections among waste handlers was determined using formol-ether concentration and modified Ziehl-Neelsen technique. About half of the workers were infected with parasites. The profile of parasitic infection revealed 12 parasitic species. These were comprised of the following helminths: Schistosoma mansoni (13.3%), Enterobius vermicularis (1.7%), Ascaris lumbricoides (1.4%), and Hymenolepis nana ova (0.6%). Among protozoa were pathogenic Entamoeba histolytica (3.2%), Giardia intestinalis (2.9%), nonpathogenic protozoa such as Entamoeba coli (1.7%), and potentially pathogenic or opportunistic ones as Cryptosporidium (23.4%), Microsporidia (20.25%), Cyclospora (2.0%), Blastocystis hominis (1.7%), and Cystoisospora belli (1.2%). About 1.4% of MSWWs have pediculosis and phthiriasis in their scalp and eyelashes respectively. Risk factors for infection were associated with direct exposure to solid fecal waste (odds ratio [OR] = 1.8, confidence interval [CI] = 1.1-3.0) and occupational activities that allowed for direct exposure to solid fecal waste (OR = 2.3, CI = 1.4-4.0). Logistic regression model has revealed that educational level and residence were the factors that contribute to parasitic infection among MSWWs (P < 0.05). MSWWs are at high risk of acquiring parasitic infections. Data of the present study highlighted the need for greater biomonitoring of MSWWs and the improvement of environmental conditions and health care in such marginalized communities to prevent parasitic infection and associated morbidities.

Molecular detection of giardiasis among children at Cairo University Pediatrics Hospitals

Giardiasis is a prevailing intestinal disease in children. This study aimed to determine molecular prevalence of Giardia intestinalis in children attending Cairo University Pediatrics Hospitals, using copro-PCR assays, conventional methods and to evaluate diagnostic effectiveness of used tests. 229 fecal samples were collected from children suffering from gastrointestinal symptoms and examined for Giardia by microscopy, Immuno-chromatographic test (ICT), copro-DNA using two PCR assays targeting tpi [nested-PCR (nPCR)] and 18S [conventional-PCR (cPCR)] genes. Out of 229 samples assessed, Giardia was diagnosed in 13.9, 17, 17.9, 4.8 % of cases using microscopy, ICT, nPCR (tpi) and cPCR (18S), respectively. Nominating both PCR assays as composite reference standard, microscopy and ICT were of reliable specificity (100 and 96.9 %) and accuracy (95.6 and 93.6 %) but of limited sensitivity (78.6 and 76.2 %). Kappa agreement showed, there was substantial agreement of ICT (0.776) and almost perfect agreement of microscopy (0.839) with PCR assays. Giardia showed a molecular prevalence of 18.3 % (42/229). ICT assay for Giardia surpassed microscopy but both couldn't be used as a consistent single detection method due to their lowered sensitivities. nPCR targeting tpi is a reliable diagnostic test aiding to determine true prevalence of Giardia.

Giardia duodenalis assemblages in Egyptian children with diarrhea

Giardia duodenalis is considered the most common cause of parasitic diarrhea worldwide. Genetic studies revealed that at least eight assemblages (A-H) exist. Of these assemblages, A and B are found primarily in human beings and occasionally in animals. The association between clinical symptoms and G. duodenalis assemblages is controversial. The aim of the present study was to determine the assemblages of G. duodenalis prevalent among Egyptian children with diarrhea. Therefore, 96 positive stool samples for Giardia by light microscopy were subjected to multilocus genotyping targeting the triose phosphate isomerase (tpi), β-giardin (bg), and glutamate dehydrogenase (gdh) genes. Amplified polymerase chain reaction (PCR) products were then purified, sequenced, and aligned with reference strains to determine the assemblages of the Giardia isolates. Out of the 96 microscopically positive stool samples for Giardia, 77 (80 %) were successfully amplified and sequenced at least at one locus. Of these, 21 (27.3 %) were shown to be assemblage A, 54 (70.1 %) assemblage B, while discordant sequence typing results were observed in 2 (2.6 %) samples. AII was the predominant subassemblage of assemblage A, while it was generally difficult to further classify assemblage B. It was concluded that infection with assemblage B was more common than that with assemblage A. No associations between epidemiological information and assemblage were detected, except with age. Although infections with assemblage B were more frequently associated with abdominal pain and acute diarrhea than with assemblage A, the difference was not statistically significant.

Prevalence of Intestinal Parasitic Infection Among Inhabitants and Tribes of Chelgerd, Iran, 2008-2009

INTRODUCTION

Although a notable development in treating and controlling of parasitic infections in recent years has occurred but, these infections are still counted as important problems in many countries.

AIM

The aim of this study is to determine the prevalence of intestinal parasitic infections in the inhabitant and tribe populations who were referred to central health care of Chelgerd, Iran.

MATERIALS AND METHODS

This descriptive cross-sectional study was carried out from April 2008 to October 2009 in Chelgerd, Iran. A total of 655 samples of feces from inhabitants and tribes were collected and each sample was examined by Direct smear, formol- ethyl acetate concentration and Trichorom staining.

RESULTS

Out of 655 stool samples, 367(56%) patients revealed at least one intestinal parasite (pathogenic /non-pathogenic protozoa/helminth), 233(67.7%) in tribes and 134(43%) in inhabitants. There was significant difference between infected inhabitants and infected tribes (p=0.001). Although the intestinal parasitic infections were more in female than male it was not statistically significant (p=0.52). There was no significant difference in various age groups. Common intestinal parasitic infections which were detected in both the populations were Giardia intestinalis (28.2%) and Blastocystis hominis (27.5%).

CONCLUSIONS

We found that the prevalence of intestinal parasitic infections was higher in the tribe than inhabitant populations. Prevalence of intestinal protozoa infections was much higher than the helminthic infections. These findings reflect poor sanitary conditions in this region. They should be educated and provided better facilities to get rid of intestinal parasitic infections.

Molecular diagnosis and genotype analysis of Giardia duodenalis in asymptomatic children from a rural area in central Colombia

Giardiasis is a parasitic infection that affects around 200 million people worldwide. This parasite presents a remarkable genetic variability observed in 8 genetic clusters named as 'assemblages' (A-H). These assemblages are host restricted and could be zoonotic where A and B infect humans and animals around the globe. The knowledge of the molecular epidemiology of human giardiasis in South-America is scarce and also the usefulness of PCR to detect this pathogen in fecal samples remains controversial. The aim of this study was to conduct a cross-sectional study to compare the molecular targets employed for the molecular diagnosis of Giardia DNA and to discriminate the parasite assemblages circulating in the studied population. We analyzed 181 fecal samples from Children at La Virgen, Cundinamarca, Colombia that were DNA-extracted and analyzed by SSU rDNA, tpi and gdh loci. We observed positivity by microscopy of 13% and by PCR around 76-80% depending on the molecular marker. Additionally, a lack of statistical concordance between microscopy and PCR was detected. Regarding the genetic assemblages, we detected assemblage A (3%), assemblage B (90%) and mixed infections assemblages A+B (7%). Hence, the sub-assemblages were typed as AI, AII, BIII and BIV across the population. This study represents a reliable attempt to understand the molecular epidemiology of giardiasis in Colombia and the use of PCR to detect cryptic infections. The epidemiological implications are herein discussed.

Epidemiology of Giardia duodenalis infection in ruminant livestock and children in the Ismailia province of Egypt: insights by genetic characterization

Background

Giardia duodenalis is a common flagellated protozoan parasite that infects the small intestine of a wide range of vertebrate hosts. This study aimed to determine whether tracing of G. duodenalis isolates by current genetic typing tools is possible using an exemplary set of samples from infected cattle, buffalo and children from the Ismailia province, Egypt.

Method

A total of 804 fecal samples from ruminant animals was collected from 191 herds and 165 samples from diarrheal children below the age of 10 years. Parasites were detected in these samples using the copro-antigen RIDA^®QUICK test and by real-time PCR. Samples were then genetically characterized based on the triosephosphate isomerase, glutamate dehydrogenase and β-giardin genes.

Results

The prevalence of G. duodenalis was 53% in ruminants and 21% in symptomatic children and infection was not positively correlated with diarrheal symptoms. Sequence typing analysis confirmed predominance of B-type sequences (>67%) in humans and E-type sequences (>81%) in ruminants over A-type sequences. For 39 samples the complete sequence information of the three marker gene fragments could be derived. Integration of the concatenated sequence information of the three marker gene fragments with the spatial data of the respective sample revealed that identical or near identical (only up to 1 out of 1358 bp different) concatenated sequencing types were spatially related in 4 out of 5 cases.

Conclusion

The risk of zoonotic infection emanating from ruminants even in high prevalence areas is negligible. Genetic characterization indicated a predominant anthropogenic cycle of infection within the pediatric population studied. Integration of sequence typing data with information on geographic origins of samples allows parasite sub-population tracing using current typing tools.

Detection and molecular characterisation of Giardia lamblia genotypes in Sharjah, United Arab Emirates

BACKGROUND

No data are available on Giardia lamblia genotypes in the United Arab Emirates (UAE). This study aimed to identify G. lamblia from DNA extracted from human stool samples to gain information on its prevalence and to perform molecular analysis on isolates collected from expatriates from different localities residing in Sharjah, UAE.

METHODS

In total, 111 healthy expatriates residing in Sharjah were screened for G. lamblia using nested PCR amplification of the small subunit ribosomal RNA (ssu-rRNA) gene. Positive samples were genotyped using a nested PCR amplifying the triosephosphate isomerase (tpi) gene to differentiate between the two human assemblages (A and B). A subset of the PCR products (n=23) were sequenced and their phylogenetic relationships were determined.

RESULTS

Of the 111 participants, 67 (60.4%) were identified as positive for the ssu-rRNA gene. When genotyped for the tpi gene, 18.9% (21/111) were of assemblage A, 17.1% (19/111) belonged to assemblage B and 5.4% (6/111) showed patterns compatible with mixed infections. A strong correlation between the presence of diarrhoea and assemblage B was observed (χ(2)=10.553; p=0.001). Moreover, an association was also observed between mixed infections (A+B) and diarrhoea (χ(2)=8.899; p=0.003). No correlation between age, gender and geographic origin of the infected individual was noted. Phylogenetic analysis showed three clusters for the tpi gene. No relationship between the clusters and the origin of samples was noted.

CONCLUSION

This study is the first to determine the infection rate and genotypic composition of Giardia in Sharjah, UAE.

Review of parasitic zoonoses in egypt

This review presents a comprehensive picture of the zoonotic parasitic diseases in Egypt, with particular reference to their relative prevalence among humans, animal reservoirs of infection, and sources of human infection. A review of the available literature indicates that many parasitic zoonoses are endemic in Egypt. Intestinal infections of parasitic zoonoses are widespread and are the leading cause of diarrhea, particularly among children and residents of rural areas. Some parasitic zoonoses are confined to specific geographic areas in Egypt, such as cutaneous leishmaniasis and zoonotic babesiosis in the Sinai. Other areas have a past history of a certain parasitic zoonoses, such as visceral leishmaniasis in the El-Agamy area in Alexandria. As a result of the implementation of control programs, a marked decrease in the prevalence of other zoonoses, such as schistosomiasis and fascioliasis has been observed. Animal reservoirs of parasitic zoonoses have been identified in Egypt, especially in rodents, stray dogs and cats, as well as vectors, typically mosquitoes and ticks, which constitute potential risks for disease transmission. Prevention and control programs against sources and reservoirs of zoonoses should be planned by public health and veterinary officers based on reliable information from systematic surveillance.

Molecular epidemiology of giardiasis among Orang Asli in Malaysia: application of the triosephosphate isomerase gene

BACKGROUND

Giardia duodenalis is a flagellate parasite which has been considered the most common protozoa infecting human worldwide. Molecular characterization of G. duodenalis isolates have revealed the existence of eight groups (Assemblage A to H) which differ in their host distribution. Assemblages A and B are found in humans and in many other mammals.

METHODS

This cross-sectional study was conducted to identify assemblage's related risk factors of G. duodenalis among Orang Asli in Malaysia. Stool samples were collected from 611 individuals aged between 2 and 74 years old of whom 266 were males and 345 were females. Socioeconomic data were collected through a pre-tested questionnaire. All stool samples were processed with formalin-ether sedimentation and Wheatley's trichrome staining techniques for the primary identification of G. duodenalis. Molecular identification was carried out by the amplification of a triosephosphate isomerase gene using nested-PCR assay.

RESULTS

Sixty-two samples (10.2%) were identified as assemblage A and 36 (5.9%) were assemblage B. Risk analysis based on the detected assemblages using univariate and logistic regression analyses identified subjects who have close contact with household pets i.e. dogs and cats (OR = 2.60; 95% CI = 1.42, 4.78; P = 0.002) was found to be significant predictor for assemblage A. On the other hand, there were three significant risk factors caused by assemblage B: (i) children ≤15 years old (OR = 2.33; 95% CI = 1.11, 4.87; P = 0.025), (ii) consuming raw vegetables (OR = 2.82; 95% CI = 1.27, 6.26; P = 0.011) and (iii) the presence of other family members infected with giardiasis (OR = 6.31; 95% CI = 2.99, 13.31; P < 0.001).

CONCLUSIONS

The present study highlighted that G. duodenalis infection among Orang Asli was caused by both assemblages with significant high prevalence of assemblage A. Therefore, taking precaution after having contact with household pets and their stool, screening and treating infected individuals, awareness on the importance of good health practices and washing vegetables are the practical intervention ways in preventing giardiasis in Orang Asli community.

Diagnostic testing for Giardia infections

The traditional method for diagnosing Giardia infections involves microscopic examination of faecal specimens for Giardia cysts. This method is subjective and relies on observer experience. From the 1980s onwards, objective techniques have been developed for diagnosing Giardia infections, and are superseding diagnostic techniques reliant on microscopy. Detection of Giardia antigen(s) by immunoassay is the basis of commercially available diagnostic kits. Various nucleic acid amplification techniques (NAATs) can demonstrate DNA of Giardia intestinalis, and have the potential to become standard approaches for diagnosing Giardia infections. Of such techniques, methods involving either fluorescent microspheres (Luminex) or isothermal amplification of DNA (loop-mediated isothermal amplification; LAMP) are especially promising.

Genetic characterization of Giardia duodenalis by sequence analysis in humans and animals in Pemba Island, Tanzania

Giardia duodenalis represents one of the most widespread human enteric parasites: about 200million people in Asia, Africa and Latin America are infected. Giardia exerts a deep impact on public health because of high prevalence and possible effects on growth and cognitive functions in infected children. The major aim of this study was to detect and genetically characterize G. duodenalis in both human and animal fecal samples collected in Pemba Island, in the archipelago of Zanzibar (Tanzania), in order to deepen the knowledge of genotypes of Giardia in this area. Between October 2009 and October 2010, we collected 45 human fecal samples from children from 2 primary schools and 60 animal fecal samples: 19 from zebus (Bos primigenius indicus) and 41 from goats (Capra hircus). Detection and genetic identification were performed by multilocus analysis of ssu-rDNA and gdh genes. In humans we found a higher prevalence of assemblage B (sub-assemblage BIV), in goats of assemblage E and in zebus of assemblage A. Our study represents an important contribution to the epidemiological knowledge of G. duodenalis in this area of Tanzania.

Molecular characterization of Giardia duodenalis in Yemen

Giardia duodenalis is an important intestinal protozoan in Yemen with infection rates ranging from 18% to 27%. To date, there has been no genotyping study to provide a better understanding of the transmission dynamic. This study was conducted to genotype and subtype G. duodenalis in Yemen. Stool samples were collected from 503 Yemeni outpatients between 1 and 80 years old, including 219 males and 284 females. Giardia cysts were detected via microscopy after the formal-ether concentration. Genotyping of Giardia was carried out using PCR and sequence analysis of the 16s rRNA and b-giardin genes. Of the 89 microscopy-positive Giardia samples, 65 were successfully sequenced, of which 66% (43 of 65) were identified as G. duodenalis assemblage A and 34% (22 of 65) as assemblage B. Further subtyping analysis based on b-giardin gene identified the presence of subtypes A2 and A3, which belong to the anthroponotic sub-assemblage AII. Data of the study suggest that anthroponotic transmission played a potential role in the transmission of giardiasis in the community. However, further genotyping and subtyping studies of specimens from humans and animals living in the same households are needed for a more definitive understanding of giardiasis transmission in Yemen.

Identification of genotypes of Giardia duodenalis human isolates in Isfahan, Iran, using polymerase chain reaction - Restriction Fragment Length polymorphism

BACKGROUND

Giardia duodenalis is one of the most prevalent intestinal parasites of human. It also infects a wide range of mammals. Two genotype of G.duodenalis (A and B) were commonly reported among humans with different frequency of distribution in different geographical locations. This work was conducted to discriminate genotypes of Giardia duodenalis human isolates in Isfahan city using PCR- RFLP. This is the first molecular study on human isolates of G.duodenalis in the area.

METHODS

Samples were collected from different health centers of Isfahan city during June 2011 and February 2012. From 175 Giardia positive stool samples 67 specimens were selected randomly. Cysts of Giardia positive samples were concentrated by flotation sucrose. Extraction of genomic DNA from trophozoite and cysts was performed using QIAamp Stool Mini kit with a modified protocol. PCR- RFLP method was used to amplify a fragment of 458bp at the glutamate dehydrogenase locus, and restriction enzymes BspLI and RsaI differentiated human genotypes A and B and their subgroups.

RESULTS

PCR - RFLP assay of 67 isolates showed 40(59.7%) isolates as Genotype A group II, 23(34.32%) samples as Genotype B Group III and two (2.98%) sample as Genotype B group IV. Mixed genotype of (AII and B) was detected only in two isolates (2.98%).

CONCLUSIONS

PCR - RFLP assay targeting gdh locus is a sensitive tool and discriminates genotypes, sub genotypes and mixed type of G.duodenalis. Results of our study suggest both anthroponotic and zoonotic origins for the infections respectively.

Giardia duodenalis genotypes and Cryptosporidium species in humans and domestic animals in Côte d'Ivoire: occurrence and evidence for environmental contamination

Giardia duodenalis genotypes and Cryptosporidium species were studied in humans and free-ranging animals living in closed enclaves in Côte d'Ivoire. Three hundred and seven stool samples were tested from humans, and 47 from freely roaming domestic animals (dogs, goats, ducks, chickens). Molecular characterization of the isolates was performed by sequence analysis of a portion of the SSU-rDNA for Giardia and the COWP gene for Cryptosporidium, and a β-giardin SYBR-green real-time PCR was also used to confirm the assignment of Giardia isolates to Assemblages. In humans, genotyping of Giardia assigned many of the sequences (43/56 by the SSU-rDNA gene, and 36/61 by the β-giardin gene) to Assemblage B. The animal species harboured only zoonotic Assemblages A and B, except for dogs, in which host specific Assemblages C and D were also detected. Cryptosporidium meleagridis, C. parvum and C. hominis were detected in humans, while among the animals only chickens were found positive for oocysts, identified as C. meleagridis and C. parvum. The results provide further evidence about the role of free-ranging domestic animals living closely with humans in the environmental dissemination and potential transmission of these anthropozoonotic pathogens to humans.

Giardiasis: a review on assemblage distribution and epidemiology in India

Giardiasis is a significant cause of diarrheal disease and associated morbidity in children and adults worldwide. In addition to diarrhea, it can also lead to malnutrition and cognitive deficits in children from developing countries. Giardia duodenalis is considered to be a species complex of several assemblages, of which assemblage A and B are predominantly associated with human infections. Assemblage type has been associated with risk of occurrence of symptoms and duration of illness. Hence genotyping of giardial isolates may help understand better the epidemiology and transmission ecology of the disease in a particular setting or area. In India, prevalence rates of Giardia infection in patients with diarrhea range from 0.4% to 70%, and asymptomatic cyst passage has been found to be as high as 50% in rural southern India. In this review, the global distribution of giardial assemblage, zoonotic transmission and the association of assemblage with disease have been discussed, followed by epidemiology of giardiasis in India.

Identification of a novel Assemblage B subgenotype and a zoonotic Assemblage C in human isolates of Giardia intestinalis in Egypt

Giardia intestinalis (G. intestinalis) is a flagellate parasite which has been considered the most common protozoan infecting human. Molecular techniques are of great value in studying the taxonomy, the zoonotic potential of animal isolates and the correlation between the genetic variability of the parasite and the range of clinical symptoms observed in humans. The present work aims at genotyping G. intestinalis isolates from Egypt using molecular techniques. PCR targeting the β-giardin locus, RFLP and sequencing were applied to 12 microscopically positive and 3 microscopically negative samples (which were positive by real time PCR targeting SSUr DNA). Two other loci, triose phosphate isomerase (TPI) gene and glutamate dehydrogenase (GDH) gene PCR and RFLP were also applied to all study isolates. The most frequent genotype was Assemblage B (13 out of 15), while Assemblage A and C were present in one sample each. This is the first report on zoonotic transmission of Assemblage C (dog genotype) to human in Egypt. Sequencing of the Assemblage B isolates revealed new subgenotypes with consistent mutations at specific positions, some of which were not characterized previously. The results shed light on the possibility that G. intestinalis can infect humans through a zoonotic route and open the door to wider investigations using different genetic loci to genotype Giardia isolates.

Detection and species identification of microsporidial infections using SYBR Green real-time PCR

Diagnosis of microsporidial infections is routinely performed by light microscopy, with unequivocal non-molecular species identification achievable only through electron microscopy. This study describes a single SYBR Green real-time PCR assay for the simultaneous detection and species identification of such infections. This assay was highly sensitive, routinely detecting infections containing 400 parasites (g stool sample)(-1), whilst species identification was achieved by differential melt curves on a Corbett Life Science Rotor-Gene 3000. A modification of the QIAamp DNA tissue extraction protocol allowed the semi-automated extraction of DNA from stools for the routine diagnosis of microsporidial infection by real-time PCR. Of 168 stool samples routinely analysed for microsporidian spores, only five were positive by microscopy. By comparison, 17 were positive for microsporidial DNA by real-time analysis, comprising 14 Enterocytozoon bieneusi, one Encephalitozoon cuniculi and two separate Pleistophora species infections.

Genotypes of Giardia intestinalis clinical isolates of gastrointestinal symptomatic and asymptomatic Saudi children

Giardiasis is the most worldwide parasitic disease with the major clinical impact on infant and children. Two genotypes were reported commonly among humans (assemblage A and B). In this study, genotypes of Giardia intestinalis clinical isolates obtaining from 24 gastrointestinal symptomatic Saudi primary school children and 16 asymptomatic ones were explored by real-time polymerase chain reaction using the high resolution melting curve analysis targeting intergenic spacer (IGS) region rDNA of G. intestinalis. Children having acute, intermittent, and chronic diarrhea were 14, 5, and 5, respectively. Among all the giardiasis subjects, assemblage B was 37.5% followed by both of assemblages AI and AII with 30% and 27.5%, respectively. Mixed infection with the three previous assemblages was present in 5% of cases. Among symptomatic children, the prevalence of assemblage B was 62.5% then followed by assemblage AI (16.7%) and assemblage AII with 12.5%. All of the children who harbored G. intestinalis assemblages B were symptomatic, while asymptomatic ones had only assemblage AI and AII with 50% each. The difference was statistically highly significant. In symptomatic patients having acute diarrhea, assemblage B was present in 71.5%, while assemblage AI and AII were equal with 7.1%. All of the patients (14.3%) with mixed infection had acute diarrhea. In intermittent diarrhea, assemblage AI and B were equally distributed with 40% each. In chronic diarrhea, assemblage AI and AII were equal with 20% each, while assemblage B was found in 60%. The difference was statistically not significant. In conclusion, assemblage B is the commonest, while assemblage A is a predominant in symptomatic and asymptomatic giardiasis Saudi children, respectively. So human transmission is the common risk factor among symptomatic, while zoonotic transmission is a common risk factor in asymptomatic ones. On the other hand, a strong correlation between assemblage B and symptoms and no relation between genotypes and types of diarrhea are found. Also, PCR with HRM in one-step closed-tube methods is able to genotype G. intestinalis IGS rDNA without using the sequencing methods or the electrophoresis.