Development of HRM real-time PCR for assemblage characterization of Giardia lamblia

Detection and molecular characterization of Blastocystis sp., Enterocytozoon bieneusi and Giardia duodenalis in asymptomatic animals in southeastern Iran

Domestic animals can harbor a variety of enteric unicellular eukaryotic parasites (EUEP) with zoonotic potential that pose risks to human health. The aim of this study was to evaluate the occurrence and genetic diversity of EUEP of zoonotic relevance in domestic animals in Iran. Faecal samples were collected from cattle, sheep, camels, goats, donkeys, horse, and dogs. A real-time PCR was performed to detect the parasites, followed by sequence-based genotyping analyses on isolates that tested positive for Enterocytozoon bieneusi, Giardia duodenalis, and Blastocystis sp.. Overall, 53 out of 200 faecal samples (26.5%, 95% CI 20.5-33.2) were positive for one or more EUEP. Enterocytozoon bieneusi was found in 23.8%, 12.0%, 26.1%, and 13.3% of cattle, sheep, goats, and camels, respectively. Giardia duodenalis was identified in 19.3% of cattle and 6.7% of camels. Blastocystis sp. was detected in 5.7% of cattle and 16.7% of camels. Enterocytozoon bieneusi genotypes macaque1, J, BEB6, and CHG3 were identified in 3.7% (1/27), 3.7% (1/27), 44.4% (12/27), and 48.2% (13/27) of the isolates, respectively. Giardia duodenalis assemblage B and Blastocystis subtype 10 were identified in one cattle and one camel isolate, respectively. These findings suggest that domestic animals could serve as potential reservoirs for EUEP of zoonotic relevance and might play a significant role in transmitting these parasites to humans and other animals.

Application of Nested-qPCR-High Resolution Melting (HRM) Technology on Strongyloides stercoralis Isolates from Iran

PURPOSE

Strongyloides stercoralis is a parasite with special characteristics presenting it as a unique nematode. Iran is an endemic area for S. stercoralis. In this study, nested-qPCR-high resolution melting (HRM) technology was applied on some human isolates of S. stercoralis from this country by focusing on evolutionary genetics analysis.

METHODS

Twelve human isolates of S. stercoralis were collected from four endemic provinces of Iran. Genomic DNA was extracted from a single filariform larva for every isolate. Using specific primers targeting partial regions in cox1 gene, nested-qPCR-HRM was performed and melting-curve profiles were analyzed alongside the evaluation of genetic proximity and phylogenetic analysis using MEGA7 and DnaSP5 software.

RESULTS

The melting temperature (Tm) values of the isolates were 77.9 °C-78.3 °C. All isolates from Guilan, Mazandaran, and Khouzestan Provinces shared Tm values of 78.2 °C to 78.3 °C, while the isolates from Hormozgan Province showed Tm values of 77.9 °C, 78.0 °C, and 78.1 °C. The phylogenetic tree illustrated that the sequences of the current study included nine haplotypes. Tajima's D index analyses showed that cox1 gene in S. stercoralis isolates was negative (Tajima's D = - 0.27).

CONCLUSION

The isolates were divided into five temperature groups. Although HRM assay compared to PCR sequencing identified more limited genetic changes, it revealed that the mean of Tm of the isolates from Hormozgan Province was lower than those of other provinces and represented specific haplotypes for this geographical region on the phylogenetic tree.

Prevalence of Giardia duodenalis in dogs and cats: Age-related predisposition, symptomatic, and asymptomatic cyst shedding

Background and Aim

Giardiasis is a protozoal disease that is globally prevalent in dogs and cats. The clinical manifestations vary, but asymptomatic cases have also been reported. This study aimed to estimate the prevalence of Giardia duodenalis in domestic dogs and cats, characterize the age susceptibility to this disease, and determine the frequency of cases in which cysts are combined with stool changes.

Materials and Methods

After centrifugation in a zinc sulfate solution (specific gravity = 1.32 g/cm3), feces of dogs (2761) and cats (1579) were examined microscopically. The age of the animals and the presence of coprological stool characteristics such as fecal odor, consistency, presence of mucus, and other pathological impurities were taken into account.

Results

G. duodenalis infection rates were 18.2% (215/1182) in dogs aged 1-12 months and 3.8% (60/1579) in dogs older than 12 months. The infection rate was 7.8% (48/615) in cats aged 1-12 months and 3.35% (33/994) in cats aged >12 months. The most frequently observed coprological abnormalities in cyst-positive animals were soft and/or mushy stool and pungent odor. In dogs, the frequency of these symptoms was 24.4% (67/275), 27.6% (76/275), and 36.4% (100/275) for soft stools, mushy stools, and pungent fecal odor, and 37.8% (31/82), 25.6% (21/82), and 19.5% (16/82), respectively. No stool changes were found when G. duodenalis cysts were detected in dogs in 24.7% (68/275) of cases and in cats in 24.4% (20/82).

Conclusion

G. duodenalis cysts are reported more frequently in domestic cats and dogs under 12 months of age than in dogs under 12 months of age. The presence of Giardia cysts is usually accompanied by a strong odor of feces and changes in their consistency. It can be concluded that it is necessary to conduct periodic surveillance for apparently healthy dogs and cats to rule out G. duodenalis infection.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genetic diversity and molecular diagnosis of Giardia

Giardia is a genus of flagellated protozoan parasites that infect the small intestine of humans and animals, causing the diarrheal illness known as giardiasis. Giardia exhibits significant genetic diversity among its isolates, which can have important implications for disease transmission and clinical presentation. This diversity is influenced by the coevolution of Giardia with its host, resulting in the development of unique genetic assemblages with distinct phenotypic characteristics. Although panmixia has not been observed, some assemblages appear to have a broader host range and exhibit higher transmission rates. Molecular diagnostic methods enable researchers to examine the genetic diversity of Giardia populations, enhancing our understanding of the genetic diversity, population structure, and transmission patterns of this pathogen and providing insights into clinical presentations of giardiasis.

The prevalence of potentially zoonotic intestinal parasites in dogs and cats in Moscow, Russia

This study was aimed to determine the prevalence of Toxocara canis/cati, Strongyloides stercoralis, Giardia spp., and Cryptosporidium spp., which occur and are potentially zoonotic to humans in domestic dogs and cats in Moscow (Russia). The fecal flotation method and larvae detection by microscopy of a direct feces smear were performed to detect Toxocara, Giardia spp., and Cryptosporidium spp. The total parasitic prevalence in dogs was as follows: Giardia spp.: 10.2 % (226/2208), Cryptosporidium spp.: 2.7 % (60/2208), T. canis: 2 % (45/2208), S. stercoralis larvae: 1.1 % (25/2208). The younger animals under were infected more than those over 12 months of age (p<0.001). The preva lence rates were along these lines: Giardia spp. (18.2 %), Cryptosporidium spp. (5.7 %), T.canis (3 %), S. stercoralis larvae (2.3 %). The overall prevalence in cats was as follows: Giardia spp. - 5.2 % (71/1350), Cryptosporidium spp. - 4.8 % (65/1350), T. cati - 4.1 % (56/1350). Similarly to dogs, the infection rates were higher in cats under 12 months of age Giardia spp. (8.2 %), Cryptosporidium spp. (8.6 %), T. cati (7.5 %. Analysis of combined infections in dogs revealed the following combinations: Giardia spp. and Cryptosporidium spp. (35.5 %) larvae of S. stercoralis sp. and Giardia spp. (32.3 %), T.canis and Giardia spp. (22.6 %), T.canis and Cryptosporidium spp. (6.6 %), T.canis and S.stercoralis and (3.2 %), respectively. In cats, only two coinfections by Giardia spp. and Cryptosporidium spp. (58.3 %), and T.cati with Giardia spp. (41.7 %) were noticed. Further research is needed to study the spread of parasitic diseases in pet animals. The data will improve countermeasures to prevent these diseases' spread among animals and humans.

Toward waterborne protozoa detection using sensing technologies

Drought and limited sufficient water resources will be the main challenges for humankind during the coming years. The lack of water resources for washing, bathing, and drinking increases the use of contaminated water and the risk of waterborne diseases. A considerable number of waterborne outbreaks are due to protozoan parasites that may remain active/alive in harsh environmental conditions. Therefore, a regular monitoring program of water resources using sensitive techniques is needed to decrease the risk of waterborne outbreaks. Wellorganized point-of-care (POC) systems with enough sensitivity and specificity is the holy grail of research for monitoring platforms. In this review, we comprehensively gathered and discussed rapid, selective, and easy-to-use biosensor and nanobiosensor technologies, developed for the early detection of common waterborne protozoa.

Multigene typing of Giardia Duodenalis isolated from tuberculosis and non-tuberculosis subjects

Giardia duodenalis is a cryptic protozoan, which has eight assemblages (A-H). Assemblages A and B are the main genotypes reported from humans with probable anthroponotic and zoonotic transmission. The current study aimed to characterize G. duodenalis assemblages in tuberculosis (TB) patients and healthy subjects using multilocus genotyping (MLG). Thirty Giardia-positive stool samples, which were obtained from TB patients and healthy subjects were included in the study. After total DNA extraction, three β-giardin (bg), triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh) genes were amplified and sequenced. Obtained sequences were compared to the GenBank database to characterize assemblages. Phylogenetic analysis using Maximum Likelihood (ML) and Tamura 3-parameter was performed for each gene. From 30 Giardia-positive subjects, 17 (57%) and 13 (43%) were from healthy and TB-infected subjects, respectively. There was no significant co-existence of Giardia and tuberculosis (P-value = 0.051). In addition, 14 (46.7%) and 16 (53.3%) of Giardia isolates were from asymptomatic and symptomatic subjects, respectively. PCR amplification was successful in 25 single samples (83.3%) consisted of 20 for tpi, 15 for bg, and 13 for gdh genes. Accordingly, 13/25 (52%) and 8/25 (32%) belonged to assemblage A and assemblages B, respectively, whereas 4/25 (16%) were either assemblage A or B with different genes at the same time. Significant correlation between assemblages and TB, age, and symptoms was not seen. The phylogenetic analyses represented no separation based on TB and gastrointestinal symptoms. Assemblage A was the predominant genotype in samples. The high frequency of assemblage AII indicated importance of anthroponotic transmission of Giardia in both healthy and TB patients. In addition, considering the exclusive reports of sub-assemblage AIII in wild ruminants, the presence of AIII in the current study have to be carefully interpreted. The inconsistency between the assemblage results of either bg or gdh loci with tpi gene signifies the insufficiency of single gene analysis and the necessity for MLG in molecular epidemiology of G. duodenalis.