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

Introduction

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

Methods

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

Results

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

Conclusion

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

Evaluation of the therapeutic effect of propolis on Fasciola gigantica and Clostridium novyi type B infections in sheep

The use of natural products for disease control is a promising approach to solving the problem of drug resistance. The aim of the research reported here was to evaluate the fasciolicidal and anti-Clostridium novyi type B activities of propolis administered orally to sheep infected with Fasciola gigantica and C. novyi type B. Sheep infected with both pathogens were divided into two groups: an infected treated group and an infected non-treated group. The treatment was oral administration of 50 mg propolis extract/kg daily for 15 days. The body weight of the sheep, fecal egg counts of F. gigantica, serum levels of F. gigantica IgG, concentrations of cytokines (IL-2, IL-10, and IL-17), and bacterial counts of C. novyi were evaluated. Following treatment, the sheep had increased body weight and a significant decrease in the egg count, which was reduced by 54.54% at 15 days post treatment. The level of anti- Fasciola IgG increased, whereas levels of IL-2, IL-10, and IL-17 decreased in propolistreated sheep. Treatment of sheep with propolis produced a significant reduction in fecal count of C. novyi, from 8 × 10⁹ to 3 × 10³ colony units per gram at 15 days post treatment. This research highlights the therapeutic potential of Egyptian propolis extract as a treatment against F. gigantica and C. novyi type B infections, and investigated its mode of action through its effect on some cellular and humoral responses in sheep with both infections.

Significance of a common 65 kDa antigen in the experimental fasciolosis and toxoplasmosis

In the current study, cross-reaction between two important zoonotic parasites; extracellular helminthes Fasciola gigantica and intracellular protozoa Toxoplasma gondii was proved by enzyme linked immunosorbent assay. Five antigens were used to identify and compare the cross-binding activities in the prepared antisera. Two F. gigantica antigens; adult flukes (FgA) and eggs (FgEA) were used to detect IgG in T. gondii naturally infected human sera (TgIHS) and experimentally infected sera of sheep (TgISS), mice (TgIMS) and rats (TgIRS). Three types of T. gondii antigens; RH (TgRHA), local sheep isolate (TgLA) and ME49 isolate (TgMEA) were used to detect cross binding activities in F. gigantica experimental infected rabbit sera (FgIRS) and F. gigantica naturally infected bovine sera (FgIBS). The cross-binding activities in the prepared antisera were strongly directed towards FgA and TgLA rather than the other antigens. The characterization of the five antigens using SDS-PAGE showed 4 common bands of FgA and TgLA; 165, 97, 76, and 65 kDa. While two common bands were observed between TgRHA, TgMEA and FgA; 165, and 65 kDa. Whereas, two common bands found between three types of T. gondii antigens and FgEA were identified; 165 and 65 kDa. The immunogenic cross-reactive bands between FgA and TgLA with F. gigantica infected bovine sera were identified by immunoblot. In FgA, the common immunogenic bands were 165, 65 and 14 kDa. While in TgLA, common immunogenic bands were 165 and 65 kDa. Whereas, the common immunogenic band between FgA and TgLA identified with T. gondii experimentally infected sheep sera was 65 kDa. The current research proves cross reaction between F. gigantica and T. gondii. One common band of 65 kDa showed broad immunogenic cross-reactivity with the developed antisera raising the prospect of being putative common immunodiagnostic candidate of both infections.