First report of prevalence and assemblage analysis of Giardia duodenalis in pigs from Guangxi Zhuang Autonomous Region, southern China

Giardia duodenalis is a common intestinal protozoan that can cause diarrhea and intestinal disease in animals and in humans. However, the prevalence and assemblages of G. duodenalis in pigs from Guangxi Zhuang Autonomous Region have not been reported. In this study, a total of 724 fecal samples (201 from nursery pigs, 183 from piglets, 175 from breeding pigs, and 165 from fattening pigs) were obtained in four areas of the region (Nanning, Yulin, Hezhou, and Guigang). The gene of the small subunit ribosomal RNA (SSU rRNA) of G. duodenalis was amplified by nested PCR. The results show that the prevalence of G. duodenalis in pigs was 3.59% (26/724), of which 14 samples belonged to assemblage A (53.85%) and 12 samples belonged to assemblage E (46.15%). The infection rates of G. duodenalis in Hezhou, Yulin, Nanning, and Guigang were 0%, 0.7%, 10.8% and 1.1%, respectively (χ2 = 45.616, p < 0.01); whereas 5.1% of breeding pigs, 6.0% of piglets, 2.4% of fattening pigs, and 1.0% of nursery pigs were infected with G. duodenalis (χ2 = 8.874, p < 0.05). The SSU rRNA-positive samples were amplified by PCR based on the β-giardin (bg), glutamate dehydrogenase (gdh), and triphosphate isomerase (tpi) genes. Ten, eight and seven positive samples were detected, respectively. Based on phylogenetic analysis of the three genetic loci sequences, a multilocus genotyping A1 was found. The findings of this study provide basic data for the development of prevention and control of G. duodenalis infections in pigs and humans in the Guangxi Zhuang Autonomous Region.

Clonal Outbreak of Trichophyton tonsurans Causing Tinea Capitis Among a Wrestling Team in Beijing, China

Trichophyton tonsurans mostly causes tinea capitis and tinea corporis and often associates with outbreaks among combat sports athletes. Here, we report an outbreak of tinea capitis caused by T. tonsurans among five juvenile athletes in a wrestling team in Beijing, China. Scrapings from the lesions of the five patients were performed by direct microscopic examination and fungal culture. The fungal pathogens were all identified as T. tonsurans by morphology and sequencing of the internal transcribed spacer (ITS) regions. Multilocus genotyping analysis was performed by sequencing of 13 gene loci. The sequences of these markers were identical among the five isolates, revealing a single genotype. Antifungal susceptibilities of terbinafine, itraconazole, fluconazole, ketoconazole, and amphotericin B against T. tonsurans was determined by broth microdilution method according to the Clinical and Laboratory Standards Institute M38-A3 document and these isolates were all susceptible to the common antifungal drugs treating tinea capitis.

Giardia duodenalis in patients with diarrhea and various animals in northeastern China: prevalence and multilocus genetic characterization

Background

Giardia duodenalis is a common parasitic diarrheal agent in humans, especially in developing countries. The aim of this study was to investigate the prevalence and multilocus genetic characterization of G. duodenalis in patients with diarrhea and animals in northeastern China, and to assess the epidemiological role of animals in the transmission of human giardiasis.

Methods

A total of 1739 fecal specimens from 413 diarrheal patients and 1326 animals comprising 16 mammal species were collected in Heilongjiang Province of China and screened for G. duodenalis by PCR and sequencing of the SSU rRNA gene. All G. duodenalis-positive specimens were subtyped by PCR and sequencing of the bg, tpi, and gdh genes. To detect additional mixed infections of different assemblages, assemblage A/B/E-specific PCRs were performed to amplify the tpi gene.

Results

Sequence analysis of the SSU rRNA gene determined the prevalence of G. duodenalis (5.81%, 24/413) in diarrheal patients, with a peak in minors aged 5–17 years, and identified assemblages A and B. MLG-AII and MLG-B1 were obtained based on concatenated nucleotide sequences of the bg, tpi, and gdh genes, with MLG-AII being identical to a cat-derived isolate reported previously. By sequence analysis of the SSU rRNA gene, G. duodenalis was detected in 214 (16.14%) animals belonging to 11 mammal species, with the prevalence ranging from 1.69 to 53.85%, and assemblages A to G were identified. Sequence analysis of the bg, tpi, and gdh genes from 46 specimens produced 31 MLGs, including MLG-AI (n = 1), MLG-B2–B8 (n = 18), and MLG-E1–E23 (n = 27).

Conclusions

The finding of G. duodenalis in diarrheal patients enhances consciousness of detecting G. duodenalis in clinical practice and emphasizes the importance of health education in local inhabitants, especially in the age group of 5–17 years. The identification of seven assemblages (A to G) and 33 MLGs reveals genetic heterogeneity of G. duodenalis in the investigated areas. Due to insufficient homology data on the zoonotic transmission of G. duodenalis, the precise epidemiological role that animals play in the transmission of human giardiasis needs to be assessed by more large-scale molecular epidemiological investigations of local humans and animals.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05269-9.

Fusarium head blight in the Russian Far East: 140 years after description of the 'drunken bread' problem

The first appearance of Fusarium head blight (FHB)—and the beginning of scientific research of this disease—occurred the Far East region of Russia at the end of the 19th century. In the summer of 2019, in the Amur region, which comprises 60–70% of grain production in the Russian Far East, flooding caused a state of emergency. The quality of wheat and barley grains grown under natural conditions of FHB outbreaks, including grain infection, fungal species composition, DNA content of F. graminearum and chemotypes, and the presence of various mycotoxins, was studied. Fusarium infection rates reached extremely high percentages, 51–98%, the majority of which were F. graminearum infections. The amount of F. graminearum DNA in wheat grain samples was higher than in the barley grain samples and averaged 6.1 and 2.1 pg/ng, respectively. The content of deoxynivalenol (DON) in the wheat samples reached 13,343 ppb and in barley reached 7,755 ppb. A multilocus genotyping assay was conducted on the partially sequenced fragments of the translation elongation factor EF-1a, ammonium ligase gene, reductase gene, and 3-O-acetyltransferase gene in 29 Fusarium graminearum sensu lato strains from the grain harvested in the Amur region. All strains from the Far East region were characterized as F. graminearum sensu stricto; 70% were the 15-AcDON chemotype, while the other strains were the 3-AcDON chemotype. According to the results, after 140 years of study of FHB, we are still not very successful in controlling this disease if conditions are favorable for pathogen development. Even at present, some of the grain harvested must be destroyed, as high contamination of mycotoxins renders it unusable.

Occurrence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis among captive mammals in the Bangladesh National Zoo

Cryptosporidium and Giardia are protozoan parasites capable of causing gastrointestinal illness in humans and animals. The purpose of this research was to determine the occurrence, genetic characteristics, and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in captive mammals at the Bangladesh National Zoo. A total of 200 fresh fecal samples from 32 mammalian species were collected and examined for Cryptosporidium spp. using nested polymerase chain reaction (PCR) targeting the small subunit (SSU) rRNA gene and G. duodenalis targeting the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. The overall infection rates of Cryptosporidium and G. duodenalis among captive mammals in the zoo were 3.5% (7/200) and 5.5% (11/200), respectively. Five species/genotypes of Cryptosporidium (C. hominis, C. andersoni, C. muris, C. felis, and Cryptosporidium deer genotype) were identified. C. hominis was subtyped as IbA12G3 by sequence analysis of the glycoprotein 60 (gp60) gene. Multilocus genotyping of G. duodenalis revealed assemblages A, B, and D. Mixed infections of assemblages B and D and A and B were found in an Asiatic jackal and a Nilgiri langur, respectively. To our knowledge, this is the first report on the occurrence and genetic identity of the two parasites among zoo animals in Bangladesh. The results suggest that zoonotic Cryptosporidium spp. and G. duodenalis are maintained in and transmitted between captive mammals. Therefore, washing, cleaning, and disinfection measures should be implemented to reduce the spread of Cryptosporidium and G. duodenalis infections.

Spatial distance between sites of sampling associated with genetic variation among Neospora caninum in aborted bovine foetuses from northern Italy

BACKGROUND

Neospora caninum, a coccidian protozoan, represents an important cause of bovine abortion. Available N. caninum strains show considerable variation in vitro and in vivo, including different virulence in cattle. To which extent sexual recombination, which is possible in the intestines of domestic dogs and closely related carnivores as definitive hosts, contributes to this variation is not clear yet.

METHODS

Aborted bovine foetuses were collected between 2015 and early 2019 from Italian Holstein Friesian dairy herds suffering from reproductive problems. A total of 198 samples were collected from 165 intensive farms located in Lombardy, northern Italy. N. caninum samples were subjected to multilocus-microsatellite genotyping using ten previously established microsatellite markers. In addition to our own data, those from a recent study providing data on five markers from other northern Italian regions were included and analysed.

RESULTS

Of the 55 samples finally subjected to genotyping, 35 were typed at all or 9 out of 10 loci and their individual multilocus-microsatellite genotype (MLMG) determined. Linear regression revealed a statistically significant association between the spatial distance of the sampling sites with the genetic distance of N. caninum MLMGs (P < 0.001). Including data from this and a previous North Italian study into eBURST analysis revealed that several of N. caninum MLMGs from northern Italy separate into four groups; most of the samples from Lombardy clustered in one of these groups. Principle component analysis revealed similar clusters and confirmed MLMG groups identified by eBURST. Variations observed between MLMGs were not equally distributed over all loci, but predominantly observed in MS7, MS6A, or MS10.

CONCLUSIONS

Our findings confirm the concept of local N. caninum subpopulations. The geographic distance of sampling was associated with the genetic distance as determined by microsatellite typing. Results suggest that multi-parental recombination in N. caninum is a rare event, but does not exclude uniparental mating. More comprehensive studies on microsatellites in N. caninum and related species like Toxoplasma gondii should be undertaken, not only to improve genotyping capabilities, but also to understand possible functions of these regions in the genomes of these parasites.

Multilocus genotyping of Giardia intestinalis in pet dogs of Medellín Colombia

According to a few parasitological and epidemiological studies, Giardia is the most prevalent parasitic infection among pet dogs in the city of Medellín, the second-largest city in Colombia. This study determined the assemblages of Giardia in the fecal samples of dogs obtained from 18 veterinary centers of Medellín. One hundred fecal samples of dogs diagnosed with Giardia using microscopy were analyzed via nested polymerase chain reaction (PCR) using three genes (gdh, bg, and tpi). The PCR products were purified and sequenced, and phylogenetic analyses were conducted using the maximum likelihood algorithm of the three loci. From the 100 samples analyzed, 47 were Giardia-positive via PCR. Genotypes C and D were detected in six samples, neither of which were associated with human infection. However, the zoonotic potential of Giardia cannot be ruled out because of the small number of samples that could be sequenced for assemblage assignation.

First multilocus sequence typing (MLST) of Giardia duodenalis isolates from humans in Romania

Background

Giardia duodenalis is one of the most prevalent and highly diverse human parasites, encompassing a complex of eight genetically distinct assemblages, each further divided into sub-assemblages. While in recent years, G. duodenalis genotype distribution patterns in humans have been intensely studied, there is still very little information available on the diversity of Giardia genotypes and sub-assemblages infecting people in Romania. In the present study, we investigated the genetic diversity of Giardia duodenalis in asymptomatic patients from Romania.

Methods

Over an 11-month period, human feces from 7805 healthy adults were screened by microscopic analysis for G. duodenalis cysts during their obligatory periodic check-ups. DNA extraction was performed from microscopic-positive fecal samples, followed by multilocus sequence typing of four genetic loci of the ITS region, gdh, tpi and bg genes, followed by DNA sequencing and phylogenetic analysis. Statistical analysis was performed using EpiInfo 2000 software.

Results

The prevalence of giardiasis in the present study was 0.42% (33/7805). Twenty-three samples (76.67%) were successfully genotyped at each locus. The bg and tpi genes had the highest typing success rate (100%). The identified assemblages were assemblage A in 27 cases (subtypes A2 and A3), and B in 3 cases.

Conclusions

To our knowledge, the present study is the first report of multilocus sequence typing of G. duodenalis isolated from humans in Romania. The present results may shed light on G. duodenalis infection in humans at a regional and national level, thus increasing awareness against this parasitic infection.

Molecular detection and phylogenetic analysis of canine tick-borne pathogens from Korea

Ticks transmit more pathogens than any other arthropod vector and are of paramount veterinary and zoonotic significance. Domestic dogs are an important reservoir of zoonotic agents, particularly because of their close contact with humans. Previous studies in Korea have examined canine tick-borne pathogens (CTBP) by ELISA and real-time PCR methods. However, phylogenetic information on CTBP in Korea is lacking. This study assessed the prevalence, risk factors, and co-infectivity of CTBP such as piroplasms, rickettsiae, Coxiella burnetii, hepatozoa, hemotropic mycoplasmas, and Borrelia spp., using PCR and phylogenetic analyses. Of the 510 dogs tested, three CTBP, including Anaplasma phagocytophilum 16S rRNA (13; 2.6 %), Hepatozoon canis 18S rRNA (2; 0.4 %), and Mycoplasma haemocanis 16S rRNA (1; 0.2 %) were detected. PCR adapted to amplify A. phagocytophilum msp2 and groEL genes generated amplicons thereof in two out of 13 positive dogs. One shelter dog was co-infected with A. phagocytophilum and M. haemocanis. However, Ehrlichia spp., Rickettsia spp., C. burnetii, Borrelia spp., Babesia spp., and Theileria spp. pathogens were not detected. To the best of our knowledge, this is the first study to undertake a phylogenetic analysis of H. canis and M. haemocanis in dogs reared in Korea. Although previous studies have improved our understanding of evolutionary behaviors and host-pathogen relations of CTBP, additional investigations are required to pin down vectors and reservoirs of CTBP in Korea. A surveillance system for arthropod vectors and CTBP in dogs should be established to monitor pathogen distribution and mitigate pathogen spread proactively, such as with ectoparasite medications in dogs.

Multilocus genotyping and risk factor analysis of Giardia duodenalis in dogs in Korea

Giardia duodenalis (syn. G. intestinalis, G. lamblia), a protozoan parasite that infects most mammals (including humans), has recently been classified into eight different groups/assemblages (A to H) based on host range and genetic characteristics. Assemblages A and B have been reported in humans and in many other animals, including dogs. This study analyzed Giardia infections, implementing multilocus genotyping, including the 18S rRNA, gdh, and β-giardin genes, in sheltered, companion, and special-purpose dogs throughout Korea. Of 640 dog stool samples, 99 (15.5%) were G. duodenalis-positive; this prevalence was similar to that previously reported in Korean calves. In addition, the prevalence was significantly higher in the southern region, and lower in non-sheltered dogs, older dogs, and in the autumn season. Phylogenetic analysis revealed that all G. duodenalis-positive samples belonged to assemblages C and D. Although no G. duodenalis assemblages A and B (mainly found in humans) were identified in this study, assemblage C was detected in the main types of dogs in contact with humans. Assemblage C, thought to be dog-specific, was recently identified in humans. As Giardia (including zoonotic assemblages) is distributed throughout Korea, dog living environments and the potential for dog-human transmission should be monitored.

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.

Infection patterns, clinical significance, and genetic characteristics of Enterocytozoon bieneusi and Giardia duodenalis in dairy cattle in Jiangsu, China

The infection patterns and clinical significance of Enterocytozoon bieneusi and Giardia duodenalis in dairy cattle remain poorly investigated despite their common occurrence. Data on the genetic diversity are also needed to understand the transmission and human-infective potential of the two pathogens. In this study, fecal specimens from 1366 dairy cattle on a large farm were examined for the presence and genotype distribution of E. bieneusi and G. duodenalis by PCR and DNA sequencing. The overall infection rates of E. bieneusi and G. duodenalis were 13.0% and 20.6%, respectively. Pre-weaned calves had significantly higher infection rates of both pathogens than post-weaned and adult cattle (P < 0.001), with peak occurrence of the pathogens in animals of 7-12 weeks. In both pre- and post-weaned calves, animals with diarrhea were 2.1-3.0 times more likely to be infected with either pathogen than those without diarrhea (P < 0.01). The E. bieneusi identified belonged to five genotypes, including J (n = 138), I (n = 21), BEB4 (n = 10), Type IV (n = 1), and a novel genotype CHC17 (n = 1). Genotype J was the dominant one in all age groups, whereas genotype I was only identified in calves of 6-11 weeks. Genotyping of G. duodenalis at three genetic loci identified assemblage E (n = 278), assemblage A (n = 2), and concurrence of the two (n = 1). Altogether, 13, 7 and 10 subtypes of assemblage E were detected at the bg, gdh, and tpi loci, respectively, forming 65 multilocus genotypes. The formation of two major clusters of MLGs in eBURST analysis indicated that intra-assemblage genetic recombination of two dominant MLGs could have led to the high genetic heterogeneity within assemblage E on a single farm. Results of this study provide much needed data on the pathogenicity of E. bieneusi and G. duodenalis in pre- and post-weaned calves. The clinical significance of the two pathogens in dairy cattle warrants further investigations.

First description of Giardia duodenalis in buffalo calves (Bubalus bubalis) in southwest region of São Paulo State, Brazil

We performed molecular characterization of Giardia duodenalis in buffalo calves from the Southwest region of São Paulo State, Brazil. A total of 183 fecal samples of Murrah breed buffaloes up to six months of age were collected. We examined these samples by the polymerase chain reaction (PCR) targeting the small-subunit ribosomal RNA gene and positive samples were characterized using additional PCR assays targeting a portion of the beta-giardin, the glutamate dehydrogenase and the triose-phosphate isomerase genes. Based on the SSU rRNA nPCR, the presence of G. duodenalis was confirmed in 12 (6.56%) of fecal samples, of these, five, four and three samples were positive for the tpi, bg and gdh genes, respectively. Assemblage identification by sequencing was successful in 6 of 12 samples and sequence analysis showed 100% genetic similarity with G. duodenalis assemblage E. This observation represents the first detection of G. duodenalis assemblage E in buffaloes calves in Brazil.

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First study of Giardia in fecal samples of buffalo calves from Brazil.

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Detection of Giardia in buffaloes by nested PCR using four genetic markers.

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Phylogenetic analysis identified Giardia duodenalis assemblage E.

MLSTar: automatic multilocus sequence typing of bacterial genomes in R

Multilocus sequence typing (MLST) is a standard tool in population genetics and bacterial epidemiology that assesses the genetic variation present in a reduced number of housekeeping genes (typically seven) along the genome. This methodology assigns arbitrary integer identifiers to genetic variations at these loci which allows us to efficiently compare bacterial isolates using allele-based methods. Now, the increasing availability of whole-genome sequences for hundreds to thousands of strains from the same bacterial species has allowed us to apply and extend MLST schemes by automatic extraction of allele information from the genomes. The PubMLST database is the most comprehensive resource of described schemes available for a wide variety of species. Here we present MLSTar as the first R package that allows us to (i) connect with the PubMLST database to select a target scheme, (ii) screen a desired set of genomes to assign alleles and sequence types, and (iii) interact with other widely used R packages to analyze and produce graphical representations of the data. We applied MLSTar to analyze more than 2,500 bacterial genomes from different species, showing great accuracy, and comparable performance with previously published command-line tools. MLSTar can be freely downloaded from http://github.com/iferres/MLSTar.

Toxoplasma genotyping in congenital toxoplasmosis in Upper Egypt: evidence of type I strain

Toxoplasma gondii has subpopulation structures in different geographical regions caused by less frequent sexual recombination, population sweeps, and biogeography. The majority of strains isolated in North America and Europe fall into one of three clonal lineages, referred to as types I, II, and III. So far, little is known about genetics of Toxoplasma strains in Africa. The present study aimed to determine the genotype of Toxoplasma strains obtained directly from trophoblastic/placental tissues of 29 complicated pregnant women using multilocus nested-PCR-RFLP technique depending on four independent genetic loci (5' SAG2 and 3' SAG2), SAG3, GRA6, and BTUB genes. All samples gave positive amplicons at 5'-3' SAG2 and SAG3 genes. Meanwhile, no amplification products were observed in 12 (41.37%) and 10 (34.48%) samples with GRA6 and BTUB genes, respectively. The restriction pattern revealed the presence of genotype I in all samples, except one sample, which revealed atypical genotype with unusual restriction pattern at 3' SAG2 gene. The negative amplifications in some samples could be due to presence of mutations or polymorphisms in the primer binding sites of these isolates, raising the possibility of mixed or recombinant genotypes. To the best of our knowledge, this is the first time to perform genotype analysis study based on Multiplex nPCR-RFLP technique for genetic characterization of T. gondii in Egypt. Besides, it is the first time to prove that the most prevalent strain of T. gondii, responsible for congenital toxoplasmosis in Upper Egypt, is the highly virulent type I. Atypical genotype was detected as well.

New multilocus genotypes of Giardia lamblia human isolates

Giardia lamblia is considered a species complex, whose members show little differences in their morphology, but have remarkable genetic variability. The aim of this study was to identify inter- and intra-assemblage genetic variation in G. lamblia among patients in Rio de Janeiro. The parasitological study was performed on faeces, and DNA was extracted from the samples which tested positive for G. lamblia. The genetic assemblages and subtypes were determined via multilocus sequence typing (MLST) using β-giardin, triose phosphate isomerase and glutamate dehydrogenase gene loci. Fourteen assemblage A samples were successfully genotyped at the three MLST loci (bg/tpi/gdh). Two previously identified multilocus genotypes were found (AII-1 and AII-4), and two novel multilocus genotypes are proposed (AII-8, profile A2/A2/A4; AII-9, profile A3/A2/A2). Sequence analysis showed that assemblage B isolates have a higher nucleotide variation than those from assemblage A. Novel assemblage B sequences are described and most (66.7%) have heterogeneous nucleotides, which prevent the definition of multilocus genotypes. This is the first time that MLST has been used to characterise G. lamblia isolates in human clinical samples from Rio de Janeiro. In addition, MLST has enabled the detection of novel subtypes in both assemblages and the description of two novel multilocus genotypes in assemblage A. This study provides new insights into the genetic diversity of assemblage A and shows that MLST should be used to characterise G. lamblia both in Brazil and globally.

High genetic diversity of Giardia duodenalis assemblage E in pre-weaned dairy calves in Shanghai, China, revealed by multilocus genotyping

Giardia duodenalis is a common parasitic protozoan in human and animals. Epidemiological and molecular data are available from dairy cattle in many industrialized countries, but information on genetic diversity at multiple genetic loci is limited, especially in pre-weaned dairy calves. In this study, 818 fecal specimens were collected from five dairy cattle farms located in suburbs of Shanghai, China, with two to five samplings per farm. G. duodenalis assemblages and subtypes were determined using multilocus genotyping (MLG) at the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) loci. The overall prevalence was 60.1% (492/818) combining data from the three genetic loci. Three G. duodenalis assemblages were detected, including E (n = 482), A (n = 5), and B (n = 1), with the concurrence of A and E in a few animals (n = 4). Intra-genotypic sequence diversity was high for assemblage E, showing 12, 13, and 17 subtypes at the bg, gdh, and tpi loci, including four, six, and eight new subtypes, respectively. All dominant subtypes (E3, E2, and E8 at the bg locus; E1 and E3 at the gdh locus; and E11 and E3 at the tpi locus) were detected on all farms at most sampling occasions, and only limited differences in subtype distribution were observed among five farms. Altogether, 58 assemblage E MLGs were identified, all of which had not been reported before, and seven (MLG-E1-MLG-E7) were each seen on multiple farms. These results indicate a high occurrence of G. duodenalis in dairy calves, the existence of high genetic heterogeneity of assemblage E on five farms, and frequent exchange of parasite populations among farms within a small geographic area. The clinical and epidemiologic significance of these observations warrants further investigations.

Prevalence and genotyping of Giardia duodenalis isolated from sheep in Henan Province, central China

Giardia duodenalis is a gastrointestinal protozoan that infects sheep. It is a well-known zoonotic pathogen and sheep have been implicated as a source of human infection. However, there have been few studies of its potential threat to public health in China. We used a multilocus analysis of the beta-giardin (bg), glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) genes to examine the occurrence and genotype distribution of G. duodenalis in sheep in China. In total, 716 fresh faecal specimens, including 89 from pre-weaned lambs (<3 months old) and 627 from post-weaned sheep (>3 months old) from nine intensive sheep farms in Henan Province, China, were examined for Giardia cysts with microscopy. Of these specimens, 6.65% (47/716; 99% CI: 6.2%-6.92%) from five farms were positive for G. duodenalis. The infection rate was significantly higher in pre-weaned lambs than in post-weaned sheep (12.36% versus 5.74%, respectively; P<0.05). Infection rates ranged from 2.8% to 17.2% on the G. duodenalis-positive farms. All G. duodenalis-positive samples were assayed with PCR followed by sequencing at the three gene loci investigated in this study. As a result, two assemblages were detected: assemblage A (n=5) and assemblage E (n=31), with some mixed E and A infections (n=3). The ratios of assemblage A to assemblage E on the different successfully sequenced G. duodenalis-positive farms were 0:1, 3:14, 1:4, and 1:12. Two new tpi sequences and one new gdh sequence were identified. Multilocus genotyping yielded seven multilocus genotypes (MLGs): one new assemblage A MLG and six assemblage E MLGs. In the phylogenetic analysis, the assemblage A MLG was more closely related to AI than to AII or AIII. The detection of G. duodenalis assemblage A in sheep has public health implications, although G. duodenalis assemblage E was predominant. The data provide basic information for control of giardiasis in human and sheep in Henan province, central China.

Genetic characterisation of Neospora caninum strains from clinical samples of zebuine foetuses obtained in abattoirs in Goiás, Brazil

The Neospora caninum microsatellite markers were applied to clinical samples. Genotyping technology involving fluorescently labelled DNA fragment analysis was used in combination with DNA sequencing for markers with complex repetitive sequences. Nineteen DNA samples from 15 brains and four hearts of naturally infected non-aborted zebuine foetuses from abattoirs in Goiás, Brazil. N. caninum had been detected in these foetuses by nested-PCR of the internal transcribed spacer-1 rRNA region, and the samples were analysed using these microsatellites. Seven complete or nearly complete allele profiles were obtained from six foetuses. Three distinct profiles of N. caninum were identified in a unique microregion (Meia Ponte) of Goiás. Two alleles for the same marker were detected in a unique foetus that was probably infected with two different strains. A new allele for one of the microsatellites is described. The multilocus analysis performed here revealed a preliminary means of discriminating between individual strains according to their geographical origins. These are the first results that have been obtained regarding the molecular characterisation of strains of N. caninum from infected zebuine foetuses in South America and reveal for the first time that there are genotypic differences in the strains that are responsible for foetal transmission in zebuine foetuses.