Intestinal Protozoan Parasite Research Articles

Conjugated linoleic acid enhances intestinal mucosal innate immunity against parasite Giardia lamblia in a murine model

Introduction: Giardia lamblia, a protozoan intestinal parasite is able to evade or suppress defense mechanisms, such as innate response. Antigen presenting cells (APC) like dendritic cells may orchestrate an immune response and support a more effective adaptive defense. Conjugated linoleic acid (CLA), a dietary lipid, has shown biological activity on APC. The aim was to evaluate the effect of CLA in intestinal innate response measuring the frequency of mucosal APC populations in Giardia lamblia murine infection.Method: The giardiasis infection model was established in C3H/HeN mice (n=32), and parasite load was followed at 0, 2, 6 and 8 days post infection (dpi). APC obtained from small intestine by enzymatic digestion were assessed by flow cytometry. Oral supplementation with CLA (50:50 of cis-9, trans-11-CLA and trans-10, cis-12-CLA isomers) and placebo control begun three days before infection and continued during first week post infection.Results: Infection kinetics showed a peak of trophozoites at 6 dpi in acute phase. Parasite load was lower in CLA group in comparison with control infected group (p<0.05). Conjugated linoleic acid stimulates innate immune response, percentage of intestinal CD11chiMHC-IIhi increases after 2 dpi, meanwhile CD11chiMHC-IIhiCD103+ APC was higher after three days of CLA supplementation than control (p<0.05). Also, the CD11c+ F4/80+ population shown a percentage increases after 6 and 8 dpi by the effect of treatment and time of infection (p<0.05).Conclusion: In conclusion CLA increased percentages of small intestine APC phenotypes CD11chiMHCIIhi, CD11chiMHCIIhiCD103+ and CD11c+ F4/80+, and reduced G. lamblia parasitic load. Further studies are needed to elucidate potential mechanisms involved in CLA immunomodulatory effect and its contribution in adaptive immune response.

Prevalence of intestinal parasites among food handlers in Kashan, central Iran, 2017-2018.

The most important transmission path of intestinal parasites is the consumption of contaminated water and food. This survey was conducted to determine the prevalence of intestinal parasites among food handlers in Kashan, central Iran. This cross-sectional study was carried on 1018 food handlers who referred to the health centers in order to receive health certificate in 2017-2018. Stool samples of food handlers were collected and examined using direct and formalin-ethyl acetate methods. Results were recorded in information form along with some demographic data such as sex, age. The data were analyzed based on the tests of descriptive statistics by SPSS 16. Of the 1018 individuals examined 851 (83.6%) were men and 167 (16.4%) were female. Infection rate was 10.2% among the population and 9 types of parasites were diagnosed totally. Rate of infection to protozoan intestinal parasites were: Blastocystis sp. 7.17%, Giardia duodenalis 1.2%, Entamoeba coli 1.27%, Endolimax nana 1.08%, Dientamoeba fragilis 0.3%, Iodamoeba butschlii 0.3%, Entamoeba histolytica/E. dispar 0.2%, Chilomastix mesnili 0.1%. Hymenolepis nana (0.1%) was the only intestinal worm that observed. In this investigation, 8.9% of the individual were infected by one parasite, 1.08% by two and 0.2% by 3 or more parasites. This study showed that infection to intestinal helminthic is rare among food handlers in Kashan but the prevalence of protozoan intestinal parasites is high that similar to other regions of Iran. To reduce the rate of parasitic infections and inhibition of their transmission, continuing the process of promoting the health level is recommended.

Molecular detection of Cryptosporidium species in street-sampled dog faeces in Ibadan, Nigeria.

Cryptosporidium, an intestinal protozoan parasite that infects a wide range of animals, is shed to the environment through the faeces of infected hosts that include humans and companion animals. Environmental contamination with infective oocysts increases the risk of transmission of this zoonotic pathogen to other susceptible host. In this study, Cryptosporidium was detected by polymerase chain reaction amplification of the 18S rRNA gene in 2.5% (5/203) of dog faecal samples randomly collected from 23 streets of Ibadan, southwestern Nigeria. Nucleotide sequencing of the 18S rRNA gene yielded two genotypes, C. parvum and C. muris in three and two samples, respectively. Further amplification of the gp60 gene-coding 60-kDa glycoprotein for subtype determination detected two isolates as C. parvum subtype IIc family. C. parvum subtype IIc is a human-derived pathogen while C. muris has been reported to infect rodents and even humans. The findings of this study suggest that free-ranging urban dogs could act as reservoirs and potential sources of environmental contamination with Cryptosporidium species of public health importance.

Occurrence and genetic diversity of Blastocystis in Korean cattle

Blastocystis is one of the most commonly detected intestinal protozoan parasites worldwide and has been found in humans and other animals. Therefore, many countries have actively researched this parasite. However, to our knowledge, no study of Blastocystis has been conducted in Korea. Therefore, we conducted a study of the current status of Blastocystis infection in domestic cattle, the various genotypes involved, and its zoonotic potential through a phylogenetic comparison with subtypes found in other studies. The feces of cattle were randomly collected throughout Korea; basic information, including collection date, sex, and cattle type was recorded, and DNA extraction, PCR, and phylogenetic analyses were performed. A total of 1,512 fecal samples were tested. The 101 Blastocystis-positive samples were obtained, yielding an approximate infection rate of 6.7%. Differences in age, cattle type, fecal type, and season were statistically significant between Blastocystis-positive and -negative cattle. In this study, four subtypes of Blastocystis (ST1, ST5, ST10, and ST14) were confirmed by phylogenetic analysis. ST1 and ST5 are potential zoonotic subtypes, therefore the possibility of zoonotic transmission cannot be ignored. Further research and clarification of the infection and transmission patterns of Blastocystis are warranted.

Prevalence of intestinal parasitic protozoan infections among female HIV/Aids patients attending Aminu Kano Teaching Hospital, Kano, Kano State, Nigeria

Intestinal protozoan parasites are the major cause of morbidity and mortality killing millions of patients with HIV/AIDS each year; causing diarrhea especially in infants and immunocompromised people worldwide. HIV infection has been modifying both the epidemiology and outcome of parasitic infections. The aim of this study was to determine the prevalence of intestinal parasitic protozoan infections among women patients with HIV/AIDS attending Aminu Kano Teaching Hospital (AKTH), Kano from October - December, 2016. Stool samples from 82 HIV/AIDS women patients were analyzed for protozoan parasite using direct wet mount, formol-ether concentration techniques and modified Ziehl-Neelson staining techniques whereas the blood samples collected were analyzed for CD4+ T-cell estimation using flow cytometry. Sociodemographic variables were collected by using questionnaire. Chi-square test was used to test the associations between CD4+ T-cell count and protozoan infections. A total of three (3) protozoan parasites were encountered among the HIV- positive individuals. These include Giardia intestinalis (33.4%), Entamoeba histolytica (27.8%) and E. coli (22.2%). The result indicated that the parasitic infection with Giardiaintestinalis was significantly higher among HIV-positive women (P>0.05). The age group with the highest prevalence was that of 40-49 years (29.2%). There was no significant difference in the prevalence of intestinal parasitic protozoan infection with regard to age, CD4+ count, job type of the patients (P>0.05) but there was a significant association between the residence area, pregnancy status and intestinal parasitic protozoan infection (P<0.05). Prevalence was also significantly higher in the rural areas (39.1%) than in the urban areas (11.4%). Routine screening for intestinal parasites in HIV-positive patients among others are advocated in the study area. Keywords: AKTH; CD4+ count; HIV/AIDS; Immunocompromised; Intestinal Protozoa; Prevalence

Modulation of human dendritic cell activity by Giardia and helminth antigens.

Giardia duodenalis is a common intestinal protozoan parasite known to modulate host immune responses, including dendritic cell (DC) function. Coinfections of intestinal pathogens are common, and thus, DCs may be concurrently exposed to antigens from multiple parasites. Here, we investigated the effects of G.duodenalis products on human monocyte-derived DC function independently and in combination with helminth antigens (Ascaris suum and Trichuris suis). All antigens individually induced an anti-inflammatory phenotype in DCs, reducing lipopolysaccharide (LPS)-induced interleukin (IL)-6, IL-12p70 and tumour necrosis factor (TNF)-α secretion. G.duodenalis and T.suis products also consistently upregulated IL-10 production. Despite a similar modulation of cytokine secretion, additive effects between Giardia and helminth products were not observed, indicating a dominant effect of a single parasite stimulus and limited interactive effects on DC function. G.duodenalis trophozoites induced rapid apoptosis in DCs, which was not observed with the helminth antigens suggesting that the modulatory effects of G.duodenalis may override that of A.suum and T.suis. Thus, G.duodenalis modulates DC activity by modulating cytokine secretion and/or inducing apoptosis, which may be a parasite-driven mechanism to dampen host immunity and establish chronic infections. The differential mechanisms of DC modulation by intestinal parasites warrant further attention.

A 63-year-old man with invasive amoebiasis mimicking pulmonary tuberculosis

Entamoeba histolytica is an intestinal protozoan parasite transmitted through the faecal–oral route. Up to 90% of E. histolytica infections are asymptomatic or associated with mild symptoms. Most cases in Canada are from residents of or travellers from areas of high endemicity, although autochthonous cases have been reported among men who have sex with men (MSM) and Canadian Indigenous populations. We present an uncommon case of amoebic liver abscess with diaphragmatic perforation and intrapulmonary extension mimicking active pulmonary tuberculosis. Amoebic liver abscesses are infrequently seen outside of endemic areas, rarely extend outside the liver, and should be suspected in cases of unexplained fever even in the absence of signs, symptoms, or basic blood tests suggestive of liver pathology.

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.

In vitro and in vivo thermal stress induces proliferation of Blastocystis sp.

Blastocystis sp. is known to be the most commonly found intestinal protozoan parasite in human fecal surveys and has been incriminated to cause diarrhea and abdominal bloating. Binary fission has been widely accepted as the plausible mode of reproduction for this parasite. The present study demonstrates that subjecting the parasites in vitro to higher temperature shows the proliferation of parasite numbers in cultures. Transmission electron microscopy was used to compare the morphology of Blastocystis sp. subtype 3 isolated from a dengue patient having high fever (in vivo thermal stress) and Blastocystis sp. 3 maintained at 41°C (in vitro thermal stress) and 37°C (control). Fluorescence stains like acridine orange (AO) and 4',6'-diamino-2-phenylindole (DAPI) were used to demonstrate the viability and nuclear content of the parasite for both the in vitro and in vivo thermal stress groups of parasites. Blastocystis sp. at 37°C was found to be mostly vacuolar whereas the in vitro thermal stressed isolates at 41°C were granular with electron dense material seen to protect the granules within the central body. Parasites of the in vivo thermal stressed group showed similar ultrastructure as the in vitro ones. AO and DAPI staining provided evidence that these granules are viable which develop into progenies of Blastocystis sp. These granular forms were then observed to rupture and release progenies from the mother cells whilst the peripheral cytoplasmic walls were seen to degrade. Upon exposure to high temperature both in vitro and in vivo, Blastocystis sp. in cultures show higher number of granular forms seen to be protected by the electron dense material within the central body possibly acting as a protective mechanism. This is possibly to ensure the ability to survive for the granules to be developed as viable progenies for release into the host system.

Giardia duodenalis Infections in Humans and Other Animals in China.

Giardia duodenalis is an important zoonotic pathogen in both public and veterinary health, and has been genotyped into at least eight assemblages (A–H), each with a distinct host range. In recent years, this intestinal protozoan parasite has been identified widely in humans and various other animals, and has even been recorded in environmental contaminants. Along with whole genome sequencing of G. duodenalis, multilocus sequence typing is increasingly being used to characterize G. duodenalis isolates. Here, we review the epidemiology, genotyping, and subtyping of G. duodenalis from humans and a wide range of other animals, as well as from wastewater, in China.

Giardia co-infection promotes the secretion of antimicrobial peptides beta-defensin 2 and trefoil factor 3 and attenuates attaching and effacing bacteria-induced intestinal disease.

Our understanding of polymicrobial gastrointestinal infections and their effects on host biology remains incompletely understood. Giardia duodenalis is an ubiquitous intestinal protozoan parasite infecting animals and humans. Concomitant infections with Giardia and other gastrointestinal pathogens commonly occur. In countries with poor sanitation, Giardia infection has been associated with decreased incidence of diarrheal disease and fever, and reduced serum inflammatory markers release, via mechanisms that remain obscure. This study analyzed Giardia spp. co-infections with attaching and effacing (A/E) pathogens, and assessed whether and how the presence of Giardia modulates host responses to A/E enteropathogens, and alters intestinal disease outcome. In mice infected with the A/E pathogen Citrobacter rodentium, co-infection with Giardia muris significantly attenuated weight loss, macro- and microscopic signs of colitis, bacterial colonization and translocation, while concurrently enhancing the production and secretion of antimicrobial peptides (AMPs) mouse β-defensin 3 and trefoil factor 3 (TFF3). Co-infection of human intestinal epithelial cells (Caco-2) monolayers with G. duodenalis trophozoites and enteropathogenic Escherichia coli (EPEC) enhanced the production of the AMPs human β-defensin 2 (HBD-2) and TFF3; this effect was inhibited with treatment of G. duodenalis with cysteine protease inhibitors. Collectively, these results suggest that Giardia infections are capable of reducing enteropathogen-induced colitis while increasing production of host AMPs. Additional studies also demonstrated that Giardia was able to directly inhibit the growth of pathogenic bacteria. These results reveal novel mechanisms whereby Giardia may protect against gastrointestinal disease induced by a co-infecting A/E enteropathogen. Our findings shed new light on how microbial-microbial interactions in the gut may protect a host during concomitant infections.

The prevalence of Giardia lamblia and Entamoeba histolytica/dispar among Iraqi provinces

Giardia lamblia and Entamoeba histolytica are intestinal protozoan parasites, widely prevalent, causing serious public health issues in developing countries. The aim of this study was to determine the prevalence of G. lamblia and E. histolytica/dispar, and also to quantify age, gender, and region related prevalence among a population from the eighteen provinces of Iraq, using the available surveillance database taken from the Ministry of Health, from January 2013 to December 2013. Prevalence of E. histolytica/dispar was significantly higher than G. lamblia. Both were found in varying prevalence in relation to sex (higher in males), age groups (higher in age group 15–44) and regions (higher in Middle Euphrates region). In this study, lower prevalence rates were observed in comparison with the similar studies conducted in Iraq, which may be as a result of the sample size, seasonal diversity, improved personal hygiene and public health services.

Prevalence, genetic diversity and potential clinical impact of blood-borne and enteric protozoan parasites in native mammals from northern Australia

A molecular survey was conducted to provide baseline information on the prevalence, genetic diversity and potential clinical impacts of blood-borne and enteric protozoans in native wild mammals from the Northern Territory (NT). A total of 209 blood and 167 faecal samples were collected from four target species; the northern brown bandicoot (Isoodon macrourus), common brushtail possum (Trichosurus vulpecula), northern quoll (Dasyurus hallucatus) and brush-tailed rabbit-rat (Conilurus penicillatus). Blood samples were screened by PCR at the 18S rRNA gene for trypanosomes, piroplasms and haemogregarines, with faecal samples tested for Cryptosporidium spp. at the 18S rRNA locus, and for Giardia spp. at the glutamate dehydrogenase (gdh) and 18S rRNA loci. The potential clinical impact was investigated by associating clinical, haematological and biochemical parameters with presence or absence of infection. Overall, 22.5% (95% CI: 17.0–28.8%) of the animals tested were positive for haemoprotozoans. Trypanosomes were found in 26.6% (95% CI: 18.7–35.7%) of the bandicoots and were identified as Trypanosoma vegrandis G6, except for one unique genotype, most similar to T. vegrandis G3 (genetic distance=7%). The prevalence of trypanosomes in possums was 23.7% (95% CI: 11.4–40.2%), and the genotypes identified clustered within the T. noyesi clade. The presence of Babesia sp. and Hepatozoon sp. was confirmed in bandicoots only, both at a prevalence of 9.7% (95% CI: 2.7–9.2%). The total prevalence of intestinal protozoan parasites observed was relatively low (3%; 95% CI: 1.0–6.9%). No evidence of clinical disease associated with protozoan parasitic infection was observed, however bandicoots positive for Trypanosoma exhibited a significantly lower packed cell volume (PCV) compared to negative bandicoots (p=0.046). To the authors’ knowledge, this is the first research conducted in the NT to characterise protozoan parasites in threatened native mammals using both molecular and morphological tools; and to assess the potential clinical impacts of these agents. The absence of clear signs of major morbidity in infected animals seems to exclude a direct association between infections with these agents and possible population decline events in northern Australian native mammals. However until the cause(s) of population decline are ascertained for each individual mammal species, further studies are required. The outcome of the present investigation may be used to inform wildlife conservation and zoonotic disease programs.

Occurrence and molecular genotyping of Giardia duodenalis and Cryptosporidium spp. in wild mesocarnivores in Spain

There is a surprisingly scarce amount of epidemiological and molecular data on the prevalence, frequency, and diversity of the intestinal protozoan parasites Giardia duodenalis and Cryptosporidium spp. in wildlife in general and mesocarnivore species in particular. Consequently, the extent of the cyst/oocyst environmental contamination attributable to these wild host species and their potential implications for public veterinary health remain largely unknown. In this molecular epidemiological survey a total of 193 individual faecal samples from badgers (Meles meles, n=70), ferrets (Mustela putorius furo, n=2), genets (Genetta genetta, n=6), Iberian lynxes (Lynx pardinus, n=6), beech martens (Martes foina, n=8), mongooses (Herpestes ichneumon, n=2), otters (Lutra lutra, n=2), polecats (Mustela putorius, n=2), red foxes (Vulpes vulpes, n=87), wildcats (Felis silvestris, n=2), and wolves (Canis lupus, n=6) were obtained from road-killed, hunted, and accidentally found carcasses, and from camera-trap surveys or animals entering rescue shelters, during the period December 2003–April 2016. Investigated specimens were collected in five Spanish autonomous regions including Andalusia (n=1), Asturias (n=69), Basque Country (n=49), Castile-La Mancha (n=38), and Extremadura (n=36). The presence of cysts/oocysts was confirmed by PCR-based methods targeting the small subunit (ssu) ribosomal RNA gene of these parasite species. Genotyping of the obtained isolates were attempted at appropriate markers including the glutamate dehydrogenase (G. duodenalis) and the 60-kDa glycoprotein (C. parvum and C. ubiquitum) loci. Overall, G. duodenalis was detected in 8% (7/87) of red foxes, a single beech marten, and a single wolf, respectively. Cryptosporidium was identified in 3% (2/70) of badgers, 8% (7/87) of red foxes, a single genet, and a single mongoose, respectively. None of the nine G. duodenalis isolates generated could be genotyped at the assemblage/sub-assemblage level. Out of the nine Cryptosporidium isolates successfully characterized, three were identified as C. canis (one in a mongoose and two in red foxes), and three as C. parvum (one in a badger and three in red foxes). The remaining three isolates were assigned to C. felis (in a red fox), C. hominis (in a badger), and C. ubiquitum (in a red fox), respectively. Two additional Cryptosporidium isolates infecting a badger and a genet, respectively, were untypable. The red fox was confirmed as a suitable host of potentially zoonotic Cryptosporidium species, mainly C. parvum and C. ubiquitum. The high mobility and wide home range of red foxes, together with their increasing presence in urban and peri-urban settings, may led to the overlapping of sylvatic and domestic cycles of the parasite, and consequently, to an increased risk of cryptosporidiosis in production animals and humans. The detection of C. hominis oocysts in a badger raises the question of whether this finding represents a true infection or a sporadic event of mechanical passage of C. hominis oocyst of anthroponotic origin.

Pattern of intestinal parasites among hospital patients at Tripoli Central Hospital, Libya

Background and Aim: Diagnosis of intestinal parasites is confirmed by the recovery of protozoan trophozoites and cysts, helminthes eggs, and larvae in stool samples in the clinical parasitological laboratory. In this study, we look at the prevalence of intestinal parasitic infections (IPIs) in outpatient department and hospitalized patients from different age groups in Tripoli Central Hospital obtained from 2007 to 2009. Materials and Methods: We have used the traditional microscopic technique to diagnose IPIs in all received stool samples during the study period. Results: In total, 18,000 stool samples were examined and it was found that 15.7% of them had at least one parasite. The overall prevalence of intestinal protozoan parasites was as follows: Entamoeba histolytica/Entamoeba dispar 5.1%, Entamoeba coli 10%, Giardia lamblia 8.1%, and Cryptosporidium parvum 1%, while the prevalence of intestinal helminthic parasites in this study was as follows: Enterobius vermicularis 5%, Ascaris lumbricoides 0.5%, and Strongyloides stercoralis 0.01%. Other species of intestinal helminthes are not widely prevalent in Libya. We have found a high prevalence of intestinal parasites, especially the intestinal protozoan parasites. The nonpathogenic protozoan, E. coli, had the highest prevalence rate (10.0%). Conclusion: We conducted the stool sample testing by routine ova and parasite methods, and a concentration technique increases the validity of the estimates.

Prevalence of Zoonotic and Other Intestinal Protozoan Parasites in Stray Cats (Felis domesticus) of Kerman, South-East of Iran

Intestinal protozoan parasites constitute a major source of diseases for stray cats and have been recognized as important public health problems in several parts of the world. Considering the potential risk of stray cats for public health, present cross-sectional study was carried out to determine the type and frequency of protozoan parasites by faecal examination. A total of 100 stray cats were examined in Kerman city, Iran, Overall 67 cats ( 67 %) were infected with at least one protozoan parasite. The following parasites, with their respective prevalence, were found; Isospora felis 38%, Isospora rivolta 25% , Toxoplasma gondii 16%, Sarcocystis spp. 8%, Cryptosporidium spp. 7%, and Giardia sp. 5%. Based on our data, the sex of stray cats was not significantly associated with the prevalence of gastrointestinal protozoan parasites. The high infection rate of zoonotic intestinal protozoan parasites in stray cats is considered to be critical from the viewpoint of public health importance.

Identification of Zoonotic Parasites isolated from Stray Dogs in Bojnurd County Located in North-East of Iran

Dog can represent as an important source of zoonotic disease and important health problem for human. They can carry dangerous parasitic diseases such as hydatidosis, toxocariasis and Coenurus cerebralis to humans and animals. This study was performed in order to determine the prevalence and intensity of zoonotic parasites among stray dogs from Bojnurd, the capital city of North Khorasan province in North West of Iran. During a program performing by Bojnurd municipal on the slow killing of stray dogs, 32 dogs from Jun 2013 till March 2015 were selected. At necropsy their alimentary canals were removed and to identify the species of helminthes, the nematodes were cleared in lactophenol and cestodes were stained using carmine acid. Intestinal protozoan parasites were detected with parasitological methods. 28 (87.5%) of 32 stray dogs infected at least with one helminth. Seven species of cestodes were isolated from examined dogs and three species of nematode were detected. Giardia sp. and Cryptosporidium sp. detected from fecal samples. This is the first study of the prevalence of intestinal zoonotic parasites in dogs in this area. It seems control of bearing stray dogs can help human health and reduction economic losses caused by stray dog’s zoonotic parasites.

Deconjugated Bile Salts Produced by Extracellular Bile-Salt Hydrolase-Like Activities from the Probiotic Lactobacillus johnsonii La1 Inhibit Giardia duodenalis In vitro Growth.

Giardiasis, currently considered a neglected disease, is caused by the intestinal protozoan parasite Giardia duodenalis and is widely spread in human as well as domestic and wild animals. The lack of appropriate medications and the spread of resistant parasite strains urgently call for the development of novel therapeutic strategies. Host microbiota or certain probiotic strains have the capacity to provide some protection against giardiasis. By combining biological and biochemical approaches, we have been able to decipher a molecular mechanism used by the probiotic strain Lactobacillus johnsonii La1 to prevent Giardia growth in vitro. We provide evidence that the supernatant of this strain contains active principle(s) not directly toxic to Giardia but able to convert non-toxic components of bile into components highly toxic to Giardia. By using bile acid profiling, these components were identified as deconjugated bile-salts. A bacterial bile-salt-hydrolase of commercial origin was able to mimic the properties of the supernatant. Mass spectrometric analysis of the bacterial supernatant identified two of the three bile-salt-hydrolases encoded in the genome of this probiotic strain. These observations document a possible mechanism by which L. johnsonii La1, by secreting, or releasing BSH-like activity(ies) in the vicinity of replicating Giardia in an environment where bile is present and abundant, can fight this parasite. This discovery has both fundamental and applied outcomes to fight giardiasis, based on local delivery of deconjugated bile salts, enzyme deconjugation of bile components, or natural or recombinant probiotic strains that secrete or release such deconjugating activities in a compartment where both bile salts and Giardia are present.

Prevalence and genotyping of Giardia duodenalis among Arabian horses in Ahvaz, southwest of Iran

Giardia duodenalis is globally recognized as an important zoonotic intestinal protozoan parasite. So far, eight assemblages of G. duodenalis (A-H) have been identified. Substantial evidence suggests the zoonotic potential of assemblages A, B, and E in livestock. In this study, the genotype of Giardia duodenalis isolates was genetically identified by determining the sequence of ssu-rRNA gene and performing polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on glutamate dehydrogenase gene of the parasite in Arabian horses from Ahvaz, located in southwest of Iran. The results revealed that assemblages AI and E (livestock-associated G. duodenalis) were present in horse isolates. Also, based on the findings, prevalence of G. duodenalis infection among horses was estimated at 35.7%. The results indicated that G. duodenalis is highly prevalent among Arabian horses, posing a zoonotic risk for giardiasis in Ahvaz, Iran.

Intestinal parasitic infestation among paediatric diarrhoea patients attending hospitals in Port Blair, Andaman and Nicobar Islands.

Acute childhood diarrhoea remains one of the leading causes of childhood morbidity and mortality in developing countries. The present study was conducted to estimate the prevalence of various intestinal parasitic infestation among children aged 5years and less suffering from acute diarrhoea disease attending hospitals in Andaman Islands. During the period from January 2012 to December 2013, a total of 675 acute diarrhoea patients were included in the study. Among these samples, 476 (70.5, 95% CI 66.9, 73.9) harboured ova/cyst of one or more intestinal parasites. Ova/cyst and trophozite of intestinal protozoan parasite was present in the stool samples of 390 (57.8, 95% CI 54.0, 61.5) children whereas ova of helminth parasite was observed in the stool samples of 105 (15.6, 95% CI 12.9, 18.5) children. Among all the parasites, Giardia lamblia trophozite had the highest prevalence of 30.5% followed by Entamoeba histolitica cyst (21.0%). The high prevalence of intestinal protozoan parasites is an indicator of a probably high carrier rate of these parasites in the community. The study is two issues that are important from public health points of view. Protozoan infestations could be the cause of diarrhoea, particularly watery diarrhoea, in a substantial proportion of the childhood diarrhoea patients attending the hospitals and anti-protozoan therapy needs to be part of the treatment regimen for watery diarrhoea among childhood diarrhoea patients. The second is the need for instituting a community based programme for controlling intestinal protozoan carriage in children as well as in adults as a step towards diarrhoea control.