Identification and molecular characterization of Cryptosporidium and Giardia in children and cattle populations from the province of Álava, North of Spain

Molecular characterisation of Giardia duodenalis from human and companion animal sources in the United Kingdom using an improved triosephosphate isomerase molecular marker

Giardia duodenalis is a protozoan parasite known for its ability to cause gastrointestinal disease in human and non-human mammals. In the UK, the full impact of this parasite has yet to be fully explored, due to the limited testing which has been undertaken in humans and the low-resolution assemblage-typing methods currently available. Rather than being primarily a travel-associated condition, a recent study has highlighted that an endemic Giardia cycle is present in the UK, although the source of human disease is unclear in the majority of cases. This study focussed on the improvement of one of the commonly used assemblage-typing assays, a nested topoisomerase phosphate (tpi) PCR, to increase the amplification success rate across both human and companion animal samples. After comparing published primers to full Giardia reference genomes, this marker protocol was optimised and then deployed to test a substantial number of human (n ​= ​79) and companion animal (n ​= ​174) samples to gain an insight into the molecular epidemiology of Giardia in the UK. One assemblage A1 and eleven assemblage A2 genotypes were detected in humans, along with and 25 assemblage B genotypes. Assemblage A1 genotypes, known to be human-infective, were found in three feline and one canine sample, while one feline sample contained assemblage A2. Additionally, four feline samples contained assemblage B, which is recognised as potentially human-infective. This study demonstrates the presence of potentially human-infective Giardia genotypes circulating in the companion animal population, notably with 17.4% (8/46) of feline-derived Giardia strains being potentially zoonotic. Using a modified tpi-based genotyping assay, this work highlights the potential for domestic pets to be involved in the endemic transmission of giardiasis in the UK and underlines the need for appropriate hygiene measures to be observed when interacting with both symptomatic and asymptomatic animals. It also serves to underline the requirement for further studies to assess the zoonotic risk of Giardia associated with companion animals in high-income countries.

A scoping review of risk factors and transmission routes associated with human giardiasis outbreaks in high-income settings

The flagellated pathogen Giardia duodenalis is one of the leading causes of parasitic gastrointestinal illness worldwide. In many higher income countries, such as the United Kingdom, the disease is often perceived as being travel-related, likely leading to the under-reporting of sporadic cases and outbreaks. A summary of the literature describing outbreaks and risk factors in higher income countries is necessary to improve our understanding of this pathogen and identify existing knowledge gaps. Initial literature searches were carried out in September 2016 and updated at regular intervals until November 2021, using appropriate search terms in Medline, Embase and PubMed databases. A total of 75 papers met the inclusion criteria, revealing that the consumption of contaminated water and contact with young children of diaper-wearing age were the most common transmission routes leading to outbreaks of giardiasis. Of the ten studies where food was primarily associated with outbreaks, food handlers accounted for eight of these. Another reported transmission route was direct contact with fecal material, which was reported in six studies as the primary transmission route. Travel-associated giardiasis was considered the sole transmission route in two studies, whereas multiple transmission routes contributed to giardiasis outbreaks in eleven studies. The evidence around zoonotic transmission was less clear and hampered by the lack of robust and regularly applied parasite molecular typing techniques. This literature review summarizes the findings of Giardia outbreak investigations and epidemiological studies in high-income countries. Transmission routes are identified and discussed to highlight the associated risk factors. These data also indicate gaps in our current knowledge that include the need for robust, in-depth molecular studies and have underscored the importance of water as a transmission route for Giardia cysts. These future molecular studies will improve our understanding of Giardia epidemiology and transmission pathways in higher income countries to prevent spread of this significantly under-reported pathogen.

GIARDIA DUODENALIS GENOTYPING NOT LINKED TO CLINICAL SYMPTOMATOLOGY AND NUTRITIONAL STATUS OF SCHOOL-AGED CHILDREN OF SOLEDAD AND GALAPA MUNICIPALITY SCHOOLS, ATLÁNTICO, COLOMBIA

Giardia duodenalis genotypes A and B have been reported in Colombia. The population consisted of 235 schoolchildren whose ages ranged from 2 to 10 yr of age from the municipalities of Soledad and Galapa in the department of Atlántico, Colombia. Fecal samples were obtained and then analyzed in triplicate using the sedimentation in formalin-ether (Ritchie's method) and direct examination techniques. Of the 235 fecal samples, 35 samples were positive for G. duodenalis; positive samples were concentrated in a sucrose gradient and sonicated for 3 cycles of 20 sec. DNA extraction was performed, and the parasites were genotyped by conventional PCR amplifying a region of the β-giardin gene. A general prevalence of G. duodenalis of 13.2% was found, and of these genotyped samples, 13 (56.7%) and 7 (20%) corresponded to genotype A, 1 (4.3%), and 3 (25%) corresponded to genotype B, and 9 (39.1%) and 2 (16.7%) were not defined, in the municipalities Soledad and Galapa, respectively. Additionally, 23 children were diagnosed with symptomatologic giardiasis, and 12 were asymptomatic; the most relevant symptoms were abdominal pain (7, 20%) and diarrhea (13, 56.7%). The nutritional status of children with Giardia genotypes A and B were as follows: 3 in a state of malnutrition (10%), 10 normal (33.3%), and 6 overweight and obese (20%) with genotype A, and 1 in a state of malnutrition (3.3%) and 3 normal (10%) with genotype B. The genotypes found in G. duodenalis did not show an association with nutritional status or with the clinical manifestations evaluated in schoolchildren.

Occurrence and Genetic Diversity of Protist Parasites in Captive Non-Human Primates, Zookeepers, and Free-Living Sympatric Rats in the Córdoba Zoo Conservation Centre, Southern Spain

Little information is currently available on the epidemiology of parasitic and commensal protist species in captive non-human primates (NHP) and their zoonotic potential. This study investigates the occurrence, molecular diversity, and potential transmission dynamics of parasitic and commensal protist species in a zoological garden in southern Spain. The prevalence and genotypes of the main enteric protist species were investigated in faecal samples from NHP (n = 51), zookeepers (n = 19) and free-living rats (n = 64) by molecular (PCR and sequencing) methods between 2018 and 2019. The presence of Leishmania spp. was also investigated in tissues from sympatric rats using PCR. Blastocystis sp. (45.1%), Entamoeba dispar (27.5%), Giardia duodenalis (21.6%), Balantioides coli (3.9%), and Enterocytozoon bieneusi (2.0%) (but not Troglodytella spp.) were detected in NHP. Giardia duodenalis (10.5%) and Blastocystis sp. (10.5%) were identified in zookeepers, while Cryptosporidium spp. (45.3%), G. duodenalis (14.1%), and Blastocystis sp. (6.25%) (but not Leishmania spp.) were detected in rats. Blastocystis ST1, ST3, and ST8 and G. duodenalis sub-assemblage AII were identified in NHP, and Blastocystis ST1 in zookeepers. Giardia duodenalis isolates failed to be genotyped in human samples. In rats, four Cryptosporidium (C. muris, C. ratti, and rat genotypes IV and V), one G. duodenalis (assemblage G), and three Blastocystis (ST4) genetic variants were detected. Our results indicate high exposure of NHP to zoonotic protist species. Zoonotic transmission of Blastocysts ST1 was highly suspected between captive NHP and zookeepers.

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.

[Giardiasis in a paediatric population of the province of castellon. Clinical details and impact]

INTRODUCTION

Giardiasis is a gastrointestinal parasitosis that has a great public health impact.

PATIENTS AND METHODS

Observational case study - in children under 15 years old in the Health Department 3 of the Province of Castellon (Spain), during the period 2012-2019.

RESULTS

A total of 190 cases of giardiasis were recorded in children under 15 years old. The number of cases varied significantly according to age group and month of the year. There were 115 males. The most frequent symptoms were diarrhea and abdominal pain. The most commonly used treatment was standard metronidazole (80% of patients). Co-infection occurred in 13% of cases, and comorbidities in 36%, especially atopic dermatitis and lactose/fructose intolerance. Relapses and/or re-infections were recorded in 8%. All cases were diagnosed by conventional parasitological stool tests and complementary immunochromatography (63 cases). Thirty-five samples were positive for Giardia duodenalis by qPCR. The direct health cost per patient was 117€. A disease notification bias was detected between 2012-2016 at a national scale.

CONCLUSIONS

Giardiasis is a current disease in Castellon, and should be considered as a probable diagnosis of gastrointestinal disease in a child under 4 years-old with diarrhea and abdominal pain. Its correct clinical and therapeutic management could reduce the possibility of worsening of the patient's condition and, additionally, would reduce the economic impact of the disease in terms of direct health costs.

Molecular Diversity of Giardia duodenalis, Cryptosporidium spp. and Blastocystis sp. in Asymptomatic School Children in Leganés, Madrid (Spain)

Enteric parasites including Giardia duodenalis, Cryptosporidium spp., and to a lesser extent, Blastocystis sp. and Enterocytozoon bieneusi, are major worldwide contributors to diarrhoeal disease. Assessing their molecular frequency and diversity is important to ascertain the sources of infection, transmission dynamics, and zoonotic potential. Little molecular information is available on the genotypes of these pathogens circulating in apparently healthy children. Here, we show that asymptomatic carriage of G. duodenalis (17.4%, 95% CI: 15.5‒19.4%), Blastocystis sp. (13.0%, 95% CI: 11.4‒14.8%), and Cryptosporidium spp. (0.9%, 95% CI: 0.5‒1.5%) is common in children (1‒16 years; n = 1512) from Madrid, Spain. Our genotyping data indicate that; (i) the observed frequency and diversity of parasite genetic variants are very similar to those previously identified in Spanish clinical samples, so that the genotype alone does not predict the clinical outcome of the infection, (ii) anthroponotic transmission accounts for a large proportion of the detected cases, highlighting that good personal hygiene practices are important to minimizing the risk of infection, (iii) Blastocystis ST4 may represent a subtype of the parasite with higher pathogenic potential, and (iv) Enterocytozoon bieneusi does not represent a public health concern in healthy children.

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.

Epidemiological distribution of genotypes of Giardia duodenalis in humans in Spain

BACKGROUND

Although the distribution of Giardia duodenalis genotypes in humans has been increasingly reported in recent years, data on possible differences in pathogen transmission between age groups and virulence between genotypes are scarce. The purpose of this study is to investigate the genetic diversity of G. duodenalis in humans in Spain and compare the distribution of G. duodenalis assemblages A and B between children and adults and clinical presentations between the two genotypes.

METHODS

In the present study, 125 microscopy-positive fecal samples were collected from humans in Spain over a 7-year period. PCR and sequence analyses of the triosephosphate isomerase, β-giardin and glutamate dehydrogenase genes were used to identify the multilocus genotypes of G. duodenalis.

RESULTS

Sequence analysis of three genetic loci identified both G. duodenalis assemblages A (29) and B (66), with co-infections of the two in two patients. Among the sequences obtained in this study, four multilocus genotypes (MLGs) of the sub-assemblage AII were observed within assemblage A. In contrast, 19 MLGs were detected within assemblage B due to the high sequence diversity at each locus. One MLG, however, was found in 51.9% (27/52) of assemblage B samples. Children were more commonly infected by assemblage B (44/53 or 83%) than adults (22/42 or 52.4%; χ2 = 10.371, df = 1, P = 0.001). Asymptomatic infection was more common in patients with assemblage A (4/29 or 13.8%) than in those with assemblage B (1/66 or 1.5%; χ2 = 6.091, df = 1, P = 0.029), and the frequency of abdominal pain occurrence was higher in assemblage B patients (65/66 or 98.5%) than assemblage A patients (25/29 or 86.2%; χ2 = 6.091, df = 1, P = 0.029).

CONCLUSIONS

These results illustrate the existence of differences in genotype distribution between children and adults and clinical presentations between G. duodenalis genotypes. They are useful in understanding the transmission of G. duodenalis in humans in Spain.

Molecular Genotyping of Giardia duodenalis in Humans in the Andimeshk County, Southwestern Iran

INTRODUCTION

Giardia duodenalis, one of the most common intestinal protozoa, infects a wide range of vertebrates, including humans and animals.

MATERIALS AND METHODS

In this study, 84 Giardia duodenalis positive stool samples were collected from 3580 patients attending the Imam Ali Hospital and two public health centers in Andimeshk County, southwestern Iran. Stool samples were examined initially by microscopy, and then G. duodenalis was confirmed by SSU rRNA gene and genotypes were determined by amplification of the gdh and β-giardin genes.

RESULTS

The SSU rRNA, gdh, and β-giardin genes were successfully amplified in 89.3%, 58.3%, and 51.2% samples, respectively. Of the positive samples for gdh and β-giardin, 40 isolates were successfully sequenced. Twenty-three isolates belonged to assemblage A, sub-assemblage AII, and 17 belonged to assemblage B. Of the 24 successfully amplified asymptomatic cases, 12 belonged to assemblage A and 12 belonged to assemblage B.

CONCLUSION

The current study found that 64.3% of the patients were asymptomatic. From an epidemiological point of view, the high percentage of asymptomatic patients is important because of their role in the transmission of Giardia. The predominant assemblage was assemblage A, sub-assemblage AII. In general, therefore, it seems that most infections are probably transmitted by anthroponotic pathways in the region.

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

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

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

Background

Giardia duodenalis is one of the most common enteric parasites in domestic animals including dogs. Young animals are more prone to the infection, with clinical manifestations ranging from asymptomatic to acute or chronic diarrhoea. Dogs are primarily infected by canine-specific (C-D) assemblages of G. duodenalis. However, zoonotic assemblages A and B have been increasingly documented in canine isolates, raising the question of whether and to which extent dogs can act as natural reservoirs of human giardiosis.

Methods

In this cross-sectional epidemiological survey we assessed the molecular diversity of G. duodenalis in dogs in the province of Castellón, Eastern Spain. A total of 348 individual faecal samples from sheltered (n = 218), breeding (n = 24), hunting (n = 68), shepherd (n = 24), and pet (n = 14) dogs were collected between 2014 and 2016. Detection of G. duodenalis cysts in faecal material was carried out by direct fluorescence microscopy as a screening test, whereas a qPCR targeting the small subunit ribosomal RNA gene of the parasite was subsequently used as a confirmatory method.

Results

Giardia duodenalis was detected in 36.5% (95% CI: 31.6–41.7%) of dogs. No significant differences in prevalence rates could be demonstrated among dogs according to their sex and geographical origin, but breeding (45.8%; 95% CI: 27.9–64.9%) and sheltered (40.4%; 95% CI: 34.1–47.0%) dogs harboured significantly higher proportions of G. duodenalis. Multi-locus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of G. duodenalis allowed the characterization of 35 canine isolates that were unambiguously assigned to assemblages A (14.3%), B (22.9%), C (5.7%), and D (37.1%). A number of inter-assemblage mixed infections including A + B (11.4%), A + D (2.9%), and A + B + D (5.7%) were also identified.

Conclusions

Data presented here are strongly indicative of high infection pressures in kennelled animals. Zoonotic sub-assemblages AII, BIII, and BIV were responsible for a considerable proportion of the G. duodenalis infections detected, but very few of the genotypes identified have been previously documented in Spanish human populations. Although possible, zoonotic transmission between dogs and humans seems an infrequent event in this Spanish region.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1353-z) contains supplementary material, which is available to authorized users.

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

Background

Human giardiosis and cryptosporidiosis are caused by the enteric protozoan parasites Giardia duodenalis and Cryptosporidium spp. Both pathogens are major contributors to the global burden of diarrhoeal disease, affecting primarily children and immunodebilitated individuals in resource-poor settings. Giardiosis and cryptosporidiosis also represent an important, often underestimate, public health threat in developed countries. In Spain only limited information is currently available on the epidemiology of these infections. Molecular data on the diversity, frequency, geographical distribution, and seasonality of G. duodenalis assemblages/sub-assemblages and Cryptosporidium species/sub-genotypes are particularly scarce.

Methods

A longitudinal molecular epidemiological survey was conducted between July 2015 to September 2016 in patients referred to or attended at the Hospital San Pedro (La Rioja, Northern Spain) that tested positive for G. duodenalis (N = 106) or Cryptosporidium spp. (N = 103) by direct microscopy and/or a rapid lateral flow immunochromatographic assay. G. duodenalis infections were subsequently confirmed by real-time PCR and positive isolates assessed by multi-locus sequence genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Cryptosporidium species and sub-genotypes were investigated at the 60 kDa glycoprotein or the small subunit ribosomal RNA genes of the parasite. Sociodemographic and clinical parameters of infected patients were also gathered and analysed.

Principal findings

Out of 90 G. duodenalis-positive isolates by real-time PCR a total of 16 isolates were successfully typed. AII (44%, 7/16) was the most prevalent sub-assemblage found, followed by BIV (31%, 5/16) and BIII (19%, 3/16). A discordant genotype result AII/AIII was identified in an additional (6%, 1/16) isolate. No mixed infections A+B were detected. Similarly, a total of 81 Cryptosporidium spp. isolates were successfully typed, revealing the presence of C. hominis (81%, 66/81) and C. parvum (19%, 15/81). Obtained GP60 sequences were assigned to sub-type families Ib (73%, 59/81) within C. hominis, and IIa (7%, 6/81) and IId (2%, 2/81) within C. parvum. A marked inter-annual variation in Cryptosporidium cases was observed.

Conclusions

Human giardiasis and cryptosporidiosis are commonly identified in patients seeking medical care in Northern Spain and represent a more important health concern than initially thought. Assemblage A within G. duodenalis and sub-genotype IbA10G2 within C. hominis were the genetic variants of these parasite species more frequently found circulating in the population under study. Molecular data presented here seem to suggest that G. duodenalis and Cryptosporidium infections arise through anthroponotic rather than zoonotic transmission in this Spanish region.

No molecular epidemiological evidence supporting household transmission of zoonotic Giardia duodenalis and Cryptosporidium spp. from pet dogs and cats in the province of Álava, Northern Spain

The role of pet dogs and cats as suitable source of human infections by the diarrheagenic protozoan parasites Giardia duodenalis and Cryptosporidium spp. has been a topic of intense debate for long time and still remains a largely unsolved problem. In this cross-sectional molecular epidemiological survey we attempted to investigate whether zoonotic (or zooanthroponotic) disease transmission was occurring among humans and domestic dogs and cats sharing the same spatial and temporal setting in both rural and urban areas of the province of Álava, Northern Spain. A total of 268 (including 179 human, 55 canine, and 34 feline) individual faecal specimens were obtained from 63 family households during February-March and November-December 2014. Detection of G. duodenalis cysts and Cryptosporidium spp. oocysts was achieved by direct fluorescence microscopy (DFAT) and PCR-based methods targeting the small subunit (SSU) ribosomal RNA gene of the parasites. Giardia-positive isolates were subsequently sub-genotyped at the glutamate dehydrogenase (GDH) and β-giardin (BG) genes. Overall, G. duodenalis infections were identified in 3.4% (6/179) of humans, 29% (16/55) of dogs, and 5.9% (2/34) of cats, respectively. Cryptosporidium spp. infections were detected in 1.1% (2/179) of humans, 5.5% (3/55) of dogs, and 8.8% (3/34) of cats, respectively. Simultaneous infections in human and canine/feline hosts by G. duodenalis or Cryptosporidium spp. were only demonstrated in a single household in which a cat and its owner tested positive for Cryptosporidium by DFAT, but this result could not be confirmed by SSU-PCR. Infections were homogeneously distributed among the studied human or animal populations irrespectively of their sex, age group, or geographical region of origin. Inadequate washing of raw vegetables and fruits was the only risk factor significantly associated to a higher likelihood of having human giardiosis/cryptosporidiosis. Molecular characterization of G. duodenalis isolates revealed the presence of sub-assemblage BIV in a single human isolate. All dog (n=3) and cat (n=2) isolates successfully genotyped were assigned to canine- and feline-specific assemblages C and F, respectively. No mixed assemblage or sub-assemblage infections could be demonstrated. Regarding Cryptosporidium, C. canis was found infecting dogs (n=2), and C. felis a single cat. Attempts to amplify and characterize Cryptosporidium human isolates failed repeatedly. Our results suggest that pet dogs and cats do not seem to play a significant role as suitable reservoirs of human giardiosis or cryptosporidiosis in the province of Álava. We conclude, therefore, that zoonotic transmission of giardiosis or cryptosporidiosis among pet dogs and cats and their owners in this geographical region is very likely a rare event.

Prevalence and risk factors for cryptosporidiosis: a global, emerging, neglected zoonosis

Background

Cryptosporidiosis is a zoonotic disease caused by the important parasitic diarrheal agent Cryptosporidium spp. Cryptosporidiosis occurs in all classes of animals and man with a rapidly expanding host range and increased importance since the occurrence of human immunodeficiency virus/acquired immunodeficiency syndrome in man.

Objectives

To review the global picture of cryptosporidiosis in man and animals with emphasis on prevalence and risk factors.

Methods

Current relevant literature on cryptosporidiosis was reviewed.

Results

Cryptosporidiosis is widely distributed and the risk factors vary from one region to another with hygiene and immune status as important risk factors.

Conclusions

Cryptosporidium spp. associated mortality has not only been reported in immune-compromised patients, but also in immune-competent patients. Yet in many countries not much attention is paid to the control and prevention of this infection in animals and man. The neglect of this disease despite the serious threat it poses to animals, their husbandry, and humans, has led the World Health Organization to list it among globally neglected diseases. To control and prevent this infection more effort needs to be directed at controlling the risk factors of the infection in man and animals.

Human cryptosporidiosis in Iran: a systematic review and meta-analysis

Cryptosporidiosis caused by Cryptosporidium spp. is an important parasitic disease that can be life-threatening for children and immunocompromised patients. This systematic review and meta-analysis was designed to determine the prevalence rate of Cryptosporidium infection and related risk factors among the Iranian general population. We searched electronic databases including Google Scholar, PubMed, Science Direct, Scopus and Proquest for articles in English and SID, Magiran, IranMedex, and IranDoc for articles in Persian. Out of 4816 studies identified in the electronic search, 94 articles were eligible for inclusion in the systematic review and meta-analysis. The prevalence rate of cryptosporidiosis by using the random effect model among children, healthy people, and gastroenteritis and immunocompromised patients in Iran was estimated as 3.65, 2.94, 1.29, and 4.54%, respectively. Findings of a phylogenetic analysis inferred by gp60 and 18S ribosomal RNA markers indicated that most of the infection rate belonged to C. parvum (particularly subtype IIaA15G2R1) and C. hominis among understudied groups. The present study is the first systematic review and meta-analysis providing a comprehensive view of the prevalence of human cryptosporidiosis and its related risk factors in Iran. It seems that the awareness of Cryptosporidium prevalence, risk factors, and disease complications may be required for developing effective strategies to prevent infection.

One Health: parasites and beyond

The field of parasitism is broad, encompassing relationships between organisms where one benefits at the expense of another. Traditionally the discipline focuses on eukaryotes, with the study of bacteria and viruses complementary but distinct. Nonetheless, parasites vary in size and complexity from single celled protozoa, to enormous plants like those in the genus Rafflesia. Lifecycles range from obligate intracellular to extensive exoparasitism. Examples of parasites include high-profile medical and zoonotic pathogens such as Plasmodium, veterinary pathogens of wild and captive animals and many of the agents which cause neglected tropical diseases, stretching to parasites which infect plants and other parasites (e.g. Kikuchi et al. 2011; Hotez et al. 2014; Blake et al. 2015; Hemingway, 2015; Meekums et al. 2015; Sandlund et al. 2015). The breadth of parasitology has been matched by the variety of ways in which parasites are studied, drawing upon biological, chemical, molecular, epidemiological and other expertise. Despite such breadth bridging between disciplines has commonly been problematic, regardless of extensive encouragement from government agencies, peer audiences and funding bodies promoting multidisciplinary research. Now, progress in understanding and collaboration can benefit from establishment of the One Health concept (Zinsstag et al. 2012; Stark et al. 2015). One Health draws upon biological, environmental, medical, veterinary and social science disciplines in order to improve human, animal and environmental health, although it remains tantalizingly difficult to engage many relevant parties. For infectious diseases traditional divides have been exacerbated as the importance of wildlife reservoirs, climate change, food production systems and socio-economic diversity have been recognized but often not addressed in a multidisciplinary manner. In response the 2015 Autumn Symposium organized by the British Society for Parasitology (BSP; https://www.bsp.uk.net/home/) was focused on One Health, running under the title 'One Health: parasites and beyond…'. The meeting, held at the Royal Veterinary College (RVC) in Camden, London from September 14th to 15th, drew upon a blend of specialist parasitology reinforced with additional complementary expertise. Scientists, advocates, policy makers and industry representatives were invited to present at the meeting, promoting and developing One Health understanding with relevance to parasitology. The decision to widen the scope of the meeting to non-parasitological, but informative topics, is reflected in the diversity of the articles included in this special issue. A key feature of the meeting was encouragement of early career scientists, with more than 35% of the delegates registered as students and 25 posters.

Identification and genotyping of Giardia spp. and Cryptosporidium spp. isolates in aquatic birds in the Salburua wetlands, Álava, Northern Spain

Aquatic birds are known to be suitable hosts for a number of avian-specific species and genotypes of the enteric protozoan parasites Giardia and Cryptosporidium. Waterbirds have also been reported as sporadic carriers of species of both pathogens from human or domestic animal origin via environmental contamination. Because aquatic birds can shed substantial amounts of infective Giardia and Cryptosporidium (oo)cysts to the environment including surface waters intended for human consumption, this situation may pose a potential risk of waterborne zoonotic disease. A total of 265 waterbird faecal samples were collected from May 2014 to June 2015 at Salburua (Álava), one of the most valued continental wetlands in northern Spain. The detection of Giardia oocyst and Cryptosporidium oocysts was carried out by direct fluorescence microscopy and molecular (PCR and sequence analysis) methods targeting the small subunit ribosomal RNA gene of the parasites. Typing of Giardia duodenalis isolates at the sub-assemblage level was based on the specific amplification and sequencing of a partial fragment of the glutamate dehydrogenase gene. Overall, Giardia cysts and Cryptosporidium oocysts were detected in 22 (8.3%) and 6 (2.3%), respectively, of the 265 faecal samples analysed. The two only Giardia isolates characterized (one novel, one known) were assigned to the sub-assemblage BIV of G. duodenalis, none of them previously reported in Spanish human isolates. This finding raises doubts about the actual origin of the infection and whether waterbirds may serve as potential source of infective Giardia cysts to humans via waterborne transmission or through direct contact. The six Cryptosporidium isolates obtained were characterized as avian genotype III (n=4), duck genotype b (n=1), and goose genotype Id (n=1), all considered avian-specific and therefore of negligible risk of zoonotic infection.

Prevalence and Risk Factors for Intestinal Protozoan Infections with Cryptosporidium, Giardia, Blastocystis and Dientamoeba among Schoolchildren in Tripoli, Lebanon

BACKGROUND

Intestinal protozoan infections are confirmed as major causes of diarrhea, particularly in children, and represent a significant, but often neglected, threat to public health. No recent data were available in Lebanon concerning the molecular epidemiology of protozoan infections in children, a vulnerable population at high risk of infection.

METHODOLOGY AND PRINCIPAL FINDINGS

In order to improve our understanding of the epidemiology of intestinal pathogenic protozoa, a cross-sectional study was conducted in a general pediatric population including both symptomatic and asymptomatic subjects. After obtaining informed consent from the parents or legal guardians, stool samples were collected in January 2013 from 249 children in 2 schools in Tripoli, Lebanon. Information obtained from a standard questionnaire included demographic characteristics, current symptoms, socioeconomic status, source of drinking water, and personal hygiene habits. After fecal examination by both microscopy and molecular tools, the overall prevalence of parasitic infections was recorded as 85%. Blastocystis spp. presented the highest infection rate (63%), followed by Dientamoeba fragilis (60.6%), Giardia duodenalis (28.5%) and Cryptosporidium spp. (10.4%). PCR was also performed to identify species and genotypes of Cryptosporidium, subtypes of Blastocystis, and assemblages of Giardia. Statistical analysis using a logistic regression model showed that contact with family members presenting gastrointestinal disorders was the primary risk factor for transmission of these protozoa.

CONCLUSIONS

This is the first study performed in Lebanon reporting the prevalence and the clinical and molecular epidemiological data associated with intestinal protozoan infections among schoolchildren in Tripoli. A high prevalence of protozoan parasites was found, with Blastocystis spp. being the most predominant protozoans. Although only 50% of children reported digestive symptoms, asymptomatic infection was observed, and these children may act as unidentified carriers. This survey provides necessary information for designing prevention and control strategies to reduce the burden of these protozoan infections, especially in children.

Molecular Genotyping of Giardia duodenalis Isolates from Symptomatic Individuals Attending Two Major Public Hospitals in Madrid, Spain

BACKGROUND

The flagellate protozoan Giardia duodenalis is an enteric parasite causing human giardiasis, a major gastrointestinal disease of global distribution affecting both developing and industrialised countries. In Spain, sporadic cases of giardiasis have been regularly identified, particularly in pediatric and immigrant populations. However, there is limited information on the genetic variability of circulating G. duodenalis isolates in the country.

METHODS

In this longitudinal molecular epidemiological study we report the diversity and frequency of the G. duodenalis assemblages and sub-assemblages identified in 199 stool samples collected from 184 individual with symptoms compatible with giardiasis presenting to two major public hospitals in Madrid for the period December 2013-January 2015. G. duodenalis cysts were initially detected by conventional microscopy and/or immunochomatography on stool samples. Confirmation of the infection was performed by direct immunofluorescence and real-time PCR methods. G. duodenalis assemblages and sub-assemblages were determined by multi-locus genotyping of the glutamate dehydrogenase (GDH) and β-giardin (BG) genes of the parasite. Sociodemographic and clinical features of patients infected with G. duodenalis were also analysed.

PRINCIPAL FINDINGS

Of 188 confirmed positive samples from 178 giardiasis cases a total of 124 G. duodenalis isolates were successfully typed at the GDH and/or the BG loci, revealing the presence of sub-assemblages BIV (62.1%), AII (15.3%), BIII (4.0%), AI (0.8%), and AIII (0.8%). Additionally, 6.5% of the isolates were only characterised at the assemblage level, being all of them assigned to assemblage B. Discordant genotype results AII/AIII or BIII/BIV were also observed in 10.5% of DNA isolates. A large number of multi-locus genotypes were identified in G. duodenalis assemblage B, but not assemblage A, isolates at both the GDH and BG loci, confirming the high degree of genetic variability observed in other molecular surveys. BIV was the most prevalent genetic variant of G. duodenalis found in individuals with symptomatic giardiasis in the population under study.

CONCLUSIONS

Human giardiasis is an ongoing public health problem in Spain affecting primarily young children under four years of age but also individuals of all age groups. Our typing and sub-typing results demonstrate that assemblage B is the most prevalent G. duodenalis assemblage circulating in patients with clinical giardiasis in Central Spain. Our analyses also revealed a large genetic variability in assemblage B (but not assemblage A) isolates of the parasite, corroborating the information obtained in similar studies in other geographical regions. We believe that molecular data presented here provide epidemiological evidence at the population level in support of the existence of genetic exchange within assemblages of G. duodenalis.

Molecular genotyping and sub-genotyping of Cryptosporidium spp. isolates from symptomatic individuals attending two major public hospitals in Madrid, Spain

Infections by members of the protozoan genus Cryptosporidium are among the most common causes of human gastrointestinal illness worldwide. In Spain cryptosporidiosis is not a compulsory notifiable disease, so the actual burden of the infection in both clinical and general populations remains largely unknown. We present here data on the diversity and frequency of the Cryptosporidium species and sub-genotypes identified in symptomatic individuals seeking medical care in two major hospitals in Madrid, Spain, between December 2013 and January 2015. Initial detection of the parasite was conducted on a total of 122 stool samples collected from 120 patients by microscopy with modified Ziehl-Neelsen and/or immunochromatographic tests. We used immunofluorescence, PCR-based methods and sequence analyses of the 60-kDa (GP60) glycoprotein and the small subunit ribosomal RNA (SSU rRNA) genes for confirmatory purposes and to characterize Cryptosporidium isolates. A total of 110 patients were confirmed with cryptosporidiosis. Overall, 101 isolates were successfully sub-genotyped at the GP60 locus, and an additional seven at the SSU rRNA locus. The analyses of all amplicons defined 10 distinct sequence types representing the GP60 family sub-genotypes IbA10G2 (78.7%), IeA11G3T3 (3.7%) of C. hominis, and the GP60 family sub-types IIaA15G2R1 (5.6%), IIaA18G6R1 (0.9%), IIcA5G3a (0.9%), IIdA18G1 (0.9%), IIdA19G1 (0.9%), IIdA21G1 (0.9%), and IIdA22G1 (0.9%) of C. parvum. A single isolate was assigned to C. felis (0.9%), two C. parvum isolates (1.9%) could not be characterized at the sub-genotype level and an additional four isolates (3.7%) were not typable. These results strongly suggest that transmission of cryptosporidiosis is mostly anthroponotic in origin in the clinical sample under study. We expect that our molecular epidemiological data will make a significant contribution to unravel the actual epidemiological situation of cryptosporidiosis in Spain, providing health care and policy makers with solid baseline information to unavoidably improve the national surveillance system and allocate additional resources to research, diagnosis, and treatment of cryptosporidiosis.

Cryptosporidiosis outbreak in a child day-care center caused by an unusual Cryptosporidium hominis subtype

INTRODUCTION

This work describes the genetic characterization of Cryptosporidium and Giardia involved in an outbreak in a nursery school in Granada, Spain, that affected seven children under the age of 4.

METHODS

Nucleic acids were extracted from the seven stool samples positive to Cryptosporidium or Giardia by microscopy and/or immunochromatography. The species and subtypes of Cryptosporidium were identified by PCR-RFLP and PCR of the SSUrRNA and gp60 genes, respectively. The assemblages of Giardia duodenalis isolates were characterized by PCR of the tpi gene. PCR products were sequenced and analyzed.

RESULTS

All of the isolates were positive for Cryptosporidium hominis. Five of them belonged to subtype IaA11R2, one to subtype IbA10G2R2, and the other could not be identified. Three of these samples were positive for G. duodenalis by PCR, two belonging to the assemblage A, and the other one to assemblage B.

DISCUSSION

This is the first report of Cryptosporidium hominis subtype IaA11R2 as a cause of an outbreak in Europe where subtype IbA10G2R2 is the most frequently identified. In the case of Giardia, an outbreak could not be confirmed because of the low number of positive samples and the low genetic variability of the amplified fragments for assemblage A of tpi gene.

CONCLUSIONS

A new subtype, of Cryptosporidium hominis named IaA11R2, has been described as a cause of an outbreak in a nursery school in Granada, Spain. However an outbreak of giardiasis could not be confirmed.

Detection and molecular characterization of Giardia duodenalis in children attending day care centers in Majadahonda, Madrid, Central Spain

Infections by the protozoan enteroparasites Giardia duodenalis and Cryptosporidium spp are a major cause of morbidity in children attending day care facilities in developed countries. In this cross-sectional study, we aimed to estimate the occurrence and genotype frequencies of these pathogens in children attending day care centers in Majadahonda, Central Spain. To do so, single stool samples were obtained from 90 children and tested for the presence of G duodenalis and Cryptosporidium spp by conventional microscopy and immunochromatography. Positive results by these techniques were subsequently confirmed by immunofluorescence microscopy. G duodenalis-positive samples were subjected to molecular characterization studies by multilocus sequence-based genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. G duodenalis assemblages were confirmed by restriction fragment length polymorphism analyses and sequencing. A socioepidemiological questionnaire was used to identify variables potentially associated with giardiasis/cryptosporidiosis in the population of children under investigation. Overall, G duodenalis and Cryptosporidium spp were detected in 15.5% and 3.3% of stool samples, respectively. Giardiasis and cryptosporidiosis were found in 3/3 and 2/3 day care centers, respectively, affecting mainly infants aged 13 to 24 months. A total of 8 G duodenalis isolates were confirmed as subassemblage BIV, all of them belonging to asymptomatic children. Attempts to genotype Cryptosporidium isolates failed. None of the variables considered could be associated with higher risk of infection with giardiasis or cryptosporidiosis. These results clearly indicate that asymptomatic infections with G duodenalis and Cryptosporidium spp are frequent in <3-year-old children in Central Spain.

First molecular characterization of Cryptosporidium and Giardia from bovines (Bos taurus and Bubalus bubalis) in Sri Lanka: unexpected absence of C. parvum from pre-weaned calves

Background

The genetic characterization of Cryptosporidium and Giardia has important implications for investigating their epidemiology and underpins their control. We undertook the first molecular epidemiological survey of domestic bovids in selected regions of Sri Lanka to establish whether they excreted Cryptosporidium and/or Giardia with zoonotic potential.

Methods

Faecal samples were collected from dairy calves (n = 340; Bos taurus; < 3 months of age; weekly sampling for six weeks) and water buffaloes (n = 297; Bubalus bubalis; <6 months and ≥6 months of age; one sampling) from seven different farms in Sri Lanka. Genomic DNAs were extracted from individual faecal samples and then tested for the presence of parasite DNA using a PCR-based mutation scanning-targeted sequencing-phylogenetic approach, employing genetic markers within the small subunit of nuclear ribosomal RNA and 60 kDa glycoprotein genes (designated pSSU and pgp60, respectively) for Cryptosporidium, and within the triose phosphate isomerise (ptpi) gene for Giardia.

Results

Based on pSSU sequence data, C. bovis, C. ryanae and six new genotypes that were genetically similar but not identical to C. andersoni (n = 1), C. bovis (n = 1), C. ryanae (n = 3) and C. suis (n = 1) were recorded in cattle. For pSSU, two other, new genotypes were defined in water buffalo, which were genetically most similar to Cryptosporidium genotypes recorded previously in this host species in other countries including Australia. Consistent with the findings for pSSU, no species or genotypes of Cryptosporidium with zoonotic potential were detected using pgp60. Based on ptpi sequence data, G. duodenalis assemblages A and E were detected in four and 137 samples from cattle, respectively, and assemblage E in two samples from water buffaloes.

Conclusions

The present study showed that C. parvum, the most commonly reported zoonotic species of Cryptosporidium recognised in bovine calves globally, was not detected in any of the samples from pre-weaned calves tested in the present study. However, eight new genotypes were recorded. Future studies of different host species in various regions are required to investigate the molecular epidemiology of cryptosporidiosis and giardiasis in Sri Lanka and neighbouring countries in South Asia.

A year-long study of Cryptosporidium species and subtypes in recreational, drinking and wastewater from the central area of Spain

A year-long longitudinal study was undertaken to evaluate the presence of Cryptosporidium spp. in drinking water treatment plants (DWTPs), wastewater treatment plants (WWTPs) and freshwater bathing beaches (FBBs) from the central area of Spain. Water samples were collected according to USEPA Method 1623, and concentrated by the IDEXX Filta-Max® system. Cryptosporidium species were detected based on PCR-restriction fragment length polymorphism and sequence analyses of the ssuRNA gene. C. hominis and/or C. parvum isolates were subtyped by DNA sequencing of the Gp60 gene. Among 150 samples, 23 (15.3%) were positive by IFAT and 40 (26.7%) by PCR. Cryptosporidium spp. was more frequent in WWTPs (26.2 and 50.8%) and FBBs (12.5 and 17.5%) by IFAT and PCR respectively. Effluent waters from DWTPs were negative for this parasite suggesting that they are suitable for public use. Tertiary treatment in the WWTPs demonstrated a high removal efficiency of Cryptosporidium in the samples evaluated. Cryptosporidium species identified included C. hominis, C. parvum, C. ubiquitum, C. andersoni and C. muris. Subtyping analysis revealed C. hominis IbA10G2 and IeA11G3T3 alleles, which is the first report of the latter in water samples. Cryptosporidium highest frequency was observed in winter and spring. Our data provide information about the occurrence and diversity of Cryptosporidium in water of human use from the central area of Spain.

Zoonotic potential of Giardia

Giardia duodenalis (syn. Giardia lamblia and Giardia intestinalis) is a common intestinal parasite of humans and mammals worldwide. Assessing the zoonotic transmission of the infection requires molecular characterization as there is considerable genetic variation within G. duodenalis. To date eight major genetic groups (assemblages) have been identified, two of which (A and B) are found in both humans and animals, whereas the remaining six (C to H) are host-specific and do not infect humans. Sequence-based surveys of single loci have identified a number of genetic variants (genotypes) within assemblages A and B in animal species, some of which may have zoonotic potential. Multi-locus typing data, however, has shown that in most cases, animals do not share identical multi-locus types with humans. Furthermore, interpretation of genotyping data is complicated by the presence of multiple alleles that generate "double peaks" in sequencing files from PCR products, and by the potential exchange of genetic material among isolates, which may account for the non-concordance in the assignment of isolates to specific assemblages. Therefore, a better understanding of the genetics of this parasite is required to allow the design of more sensitive and variable subtyping tools, that in turn may help unravel the complex epidemiology of this infection.

[Molecular characterization of Cryptosporidium spp. isolated in humans in two different locations in Spain]

Molecular PCR based diagnostic techniques have enabled us to distinguish between the different, morphologically identical, Cryptosporidium species that can infect humans. Of the 23 recognized species in the genus, at least 9 are able to infect humans. As the intensity of the clinical manifestations, pathogenicity, excretion of oocysts, and incidence, are different between this species, molecular studies are crucial for a better understanding of the epidemiology of human cryptosporidiosis. Samples form two independent studies are analyzed in this publication. One included 23 samples from Madrid, and the other, 72 samples from La Coruña. All of them positive for Cryptosporidium spp. by microscopic methods and belonging to isolated cases of human cryptosporidiosis. For the identification of the species responsible for the infection, the 18S rDNA diagnostic region and the COWP gene diagnostic regions were used. Out of the 95 samples tested, in 77 cases we were able to extract and amplify DNA. In those cases the species responsible for the infection were: C. parvum (40 cases, 2 Madrid and 38 La Coruña), C. hominis (30 cases, 10 Madrid and 20 La Coruña) and C. meleagridis (2 cases, 1 Madrid and 1 La Coruña). In 5 samples it was impossible to detect the species responsible for the infection, but their positivity was confirmed by PCR (4 Madrid and 1 La Coruña). The genotypes of the isolates from patients correlated well with animals from the same regions.

Detection of concurrent infection of dairy cattle with Blastocystis, Cryptosporidium, Giardia, and Enterocytozoon by molecular and microscopic methods

Of fecal specimens examined from 47 dairy cattle ranging in age from neonates to multiparous cows, 9, 10, 24, and 17 were positive for Blastocystis spp., Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi, respectively, as determined by PCR. Eight 3- to 5-month-old cattle were concurrently infected with three or four of these parasites. This is the first report to identify multiple concurrent infections with these four potentially zoonotic protist pathogens in cattle. None of the cattle exhibited signs of illness or effects of infection on growth and are regarded as healthy carriers. A commercially available immunofluorescence (IFA) microscopic test confirmed six of seven available PCR-positive Blastocystis specimens and identified one IFA-positive cow that was PCR negative.