Inhibitory effect of allicin on the growth of Babesia and Theileria equi parasites

Allicin is an active ingredient of garlic that has antibacterial, antifungal, antiviral, and antiprotozoal activity. However, the inhibitory effects of allicin on Babesia parasites have not yet been examined. In the present study, allicin was tested as a potent inhibitor against the in vitro growth of bovine and equine Babesia parasites and the in vivo growth of Babesia microti in a mouse model. The in vitro growth of Babesia bovis, Babesia bigemina, Babesia caballi, or Theileria equi was inhibited by allicin in a dose-dependent manner and had IC50 values of 818, 675, 470, and 742 μM, respectively. Moreover, allicin significantly inhibited (P < 0.001) invasion of B. bovis, B. bigemina, B. caballi, and T. equi into the host erythrocyte. Furthermore, mice treated with 30 mg/kg of allicin for 5 days significantly (P < 0.05) reduced the parasitemia of B. microti over the period of the study. To further examine the potential synergism of allicin with diminazene aceturate, growth inhibitory assays were performed in vitro and in vivo. Interestingly, combinations of diminazene aceturate with allicin synergistically potentiated its inhibitory effects in vitro and in vivo. These results indicate that allicin might be beneficial for the treatment of babesiosis, particularly when used in combination with diminazene aceturate.

Large-scale drug screening against Babesia divergens parasite using a fluorescence-based high-throughput screening assay

The validation of a fluorescence-based high-throughput screening (HTS) assay for determining the efficacies of large chemical libraries against Babesia divergens (bovine strain) in in vitro cultures was evaluated in this study. Hematocrits (HCTs) of 2.5%, 5%, and 10% were used for the in vitro culture at 1% parasitemia without daily replacement of the medium. Linearity and HTS assay results revealed that the best HCTs were 5% and 10%. The obtained IC50 values of diminazene aceturate, either by fluorescence-based HTS assay with and without daily replacement of medium or by fluorescence- and microscopy-based methods, did not differ significantly at 5% HCT. Actinonin and chloroquine diphosphate were the most effective drugs against the in vitro growth of B. divergens, followed by pyronaridine tetraphosphate- and luteolin-treated cultures. On contrary, tetracycline hydrochloride and (-)-epigallocatechin-3-gallate from green tea exhibited poor activity as compared with diminazene aceturate (positive control drug). The data indicated that 5% HCT without daily replacement of the culture medium mixed with bovine serum in vitro using a fluorescence-based HTS assay creates the best conditions for large-scale drug screening against B. divergens that infect cattle.

Inhibitory effects of fluoroquinolone antibiotics on Babesia divergens and Babesia microti, blood parasites of veterinary and zoonotic importance

Aim

This study aimed to evaluate the inhibitory effects of fluoroquinolone antibiotics, including enrofloxacin, enoxacin, trovafloxacin, norfloxacin, and ofloxacin, on the in vitro and in vivo growth of Babesia divergens and Babesia microti parasites, respectively.

Materials and methods

The in vitro and in vivo inhibitory effects of fluoroquinolone antibiotics against B. divergens and B. microti, respectively were evaluated using fluorescence-based assay. Additionally, combination therapies of highly effective fluoroquinolone antibiotics (enrofloxacin, enoxacin, and trovafloxacin) with diminazene aceturate, luteolin, or pyronaridine tetraphosphate were tested on the in vitro cultures of B. divergens.

Results

Enrofloxacin, trovafloxacin, and enoxacin were the most effective fluoroquinolones against the in vitro growth of B. divergens, followed by norfloxacin and ofloxacin. Furthermore, a combination of enoxacin or trovafloxacin with either diminazene aceturate, luteolin, or pyronaridine tetraphosphate significantly enhanced the inhibitory effect on the growth of B. divergens in in vitro cultures. In mice infected by B. microti, enoxacin and diminazene aceturate combination therapy exhibited a potential antibabesial effect.

Conclusion

These results suggest that safe and cheap fluoroquinolone, such as enoxacin, might be used for the treatment of clinical cases caused by Babesia spp. in animals or humans.

Secretion of a new spherical body protein of Babesia bovis into the cytoplasm of infected erythrocytes

A cDNA encoding a new Babesia bovis spherical body protein 4 (BbSBP-4) was reported to have no significant homology to other apicomplexan proteins or previously reported B. bovis spherical body proteins. In the present study, we further examined the molecular characteristics of BbSBP-4 including the expression and cellular localization of the BbSBP-4. An anti-rBbSBP-4 mouse serum specifically reacted to a 41-kDa native protein B. bovis in Western blot analysis. The immunoelectron microscopic examination confirmed the localization of BbSBP-4 in spherical bodies, but not in the nucleus, rhoptries, and micronemes. Interestingly, the protein was found to be localized not only in the spherical body of B. bovis but also in the cytoplasm of infected erythrocytes (iRBC) at the later stage of parasite development. The confocal laser microscopic examination and Western blot analysis demonstrated the increased accumulation of BbSBP-4 in the cytoplasm of iRBC and in the supernatant of cultivated B. bovis during the late developmental stage of the parasite. These results suggest that BbSBP-4 was secreted from spherical body into cytoplasm of iRBC during the late developmental stage of the parasite before the rupture of infected RBC. Taken together, BbSBP-4 might play an important role as a secreted protein in the intracellular development and/or survival of B. bovis.

Performance and consistency of a fluorescence-based high-throughput screening assay for use in Babesia drug screening in mice

In this study, we evaluated the validity of a fluorescence-based assay using SYBR Green I (SG I) stain for screening antibabesial compounds against B. microti in mice. Two different hematocrits (HCTs; 2.5% and 5%) were used. Correlating relative fluorescence units (RFUs) with parasitemia showed significant linear relationships with R² values of 0.97 and 0.99 at HCTs of 2.5% and 5%, respectively. Meanwhile, the Z′ factors in a high-throughput screening (HTS) assay were within the permissible limit (≥0.5) at 2.5% HCT and lower than this value at 5% HCT. Taken together, the highest signal-to-noise (S/N) ratios were obtained at 2.5% HCT; therefore, we concluded that 2.5% was the best HCT for applying fluorescence assay in antibabesial drug screening in mice. Additionally, positive control mice and those treated with diminazene aceturate, pyronaridine tetraphosphate, and an allicin/diminazene aceturate combination showed peak parasitemia and fluorescence values on the same day post-inoculation. Moreover, using different concentrations of SG I revealed that the optimal concentration was 2x. In summary, considering that all experiments were applied under optimal laboratory conditions, fluorescence assay at 2.5% HCT using 2x SG I for B. microti parasite offers a novel approach for drug screening in mice.

Evaluation of the inhibitory effect of N-acetyl-L-cysteine on Babesia and Theileria parasites

N-acetyl-L-cysteine is known to have antibacterial, antiviral, antimalarial, and antioxidant activities. Therefore, the in vitro inhibitory effect of this hit was evaluated in the present study on the growth of Babesia and Theileria parasites. The in vitro growth of Babesia bovis, Babesia bigemina, Babesia divergens, Theileria equi, and Babesia caballi that were tested was significantly inhibited (P < 0.05) by micromolar concentrations of N-acetyl-L-cysteine. The inhibitory effect of N-acetyl-L-cysteine was synergistically potentiated when used in combination with diminazene aceturate on B. bovis and B. caballi cultures. These results indicate that N-acetyl-L-cysteine might be used as a drug for the treatment of babesiosis, especially when used in combination with diminazene aceturate.

Molecular characterization of a new Babesia bovis thrombospondin-related anonymous protein (BbTRAP2)

A gene encoding a Babesia bovis protein that shares significant degree of similarity to other apicomplexan thrombospondin-related anonymous proteins (TRAPs) was found in the genomic database and designated as BbTRAP2. Recombinant protein containing a conserved region of BbTRAP2 was produced in E. coli. A high antigenicity of recombinant BbTRAP2 (rBbTRAP2) was observed with field B. bovis-infected bovine sera collected from geographically different regions of the world. Moreover, antiserum against rBbTRAP2 specifically reacted with the authentic protein by Western blot analysis and an indirect fluorescent antibody test. Three bands corresponding to 104-, 76-, and 44-kDa proteins were identified in the parasite lysates and two bands of 76- and 44-kDa proteins were detected in the supernatant of cultivated parasites, indicating that BbTRAP2 was proteolytically processed and shed into the culture. Apical and surface localizations of BbTRAP2 were observed in the intracellular and extracellular parasites, respectively, by confocal laser microscopic examination. Moreover, native BbTRAP2 was precipitated by bovine erythrocytes, suggesting its role in the attachment to erythrocytes. Furthermore, the specific antibody to rBbTRAP2 inhibited the growth of B. bovis in a concentration-dependent manner. Consistently, pre-incubation of the free merozoites with the antibody to rBbTRAP2 resulted in an inhibition of the parasite invasion into host erythrocytes. Interestingly, the antibody to rBbTRAP2 was the most inhibitive for the parasite’s growth as compared to those of a set of antisera produced against different recombinant proteins, including merozoite surface antigen 2c (BbMSA-2c), rhoptry-associated protein 1 C-terminal (BbRAP-1CT), and spherical body protein 1 (BbSBP-1). These results suggest that BbTRAP2 might be a potential candidate for development of a subunit vaccine against B. bovis infection.

Development and evaluation of a nested PCR based on spherical body protein 2 gene for the diagnosis of Babesia bovis infection

We developed and evaluated a nested PCR assay for the diagnosis of Babesia bovis infection in cattle based on the spherical body protein 2 gene (SBP2) from B. bovis. The specificity and sensitivity of the test were compared with the B. bovis RAP-1 gene nPCR. The SBP2 primers have specificities of 100% for B. bovis DNA. The sensitivity of the SBP2 nPCR to B. bovis from the in vitro cultured parasites was higher than that of the B. bovis RAP-1 gene nPCR, and a parasitemia as low as 10(-8)% was detected. The sensitivity of the SBP2 nPCR to B. bovis-diluted genomic DNA was also higher than that of B. bovis RAP-1 gene nPCR, and as little as 1fg per test detected. For field applications, the sensitivity to a total of 145 field samples from Ghana, Mongolia, and Brazil was evaluated. The nPCR assay of spherical body protein-2 gene detected 87.6% (127/145), while B. bovis RAP-1 gene nPCR detected 37.2% (51/145) of the total samples examined. This nPCR assay provides a good diagnostic tool for the laboratory diagnostic assessment of B. bovis infection in cattle worldwide.

Myrrh Oil in Vitro Inhibitory Growth on Bovine and Equine Piroplasm Parasites and Babesia microti of Mice

The present experimental study was conducted for the assessment of the efficacy of in vitro inhibition of myrrh oil on the propagation of Babesia bovis, B. divergens, B. bigemina, Theileria equi, and B. caballi and in vivo efficacy on B. microti in mice through fluorescence assay based on SYBR green I. The culture of B. divergens B. bovis and was used to evaluate the in vitro possible interaction between myrrh oil and other commercial compound, such as pyronaridine tetraphosphate (PYR), diminazene aceturate (DA), or luteolin. Nested-polymerase chain reaction protocol using primers of the small-subunit rRNA of B. microti was employed to detect any remnants of DNA for studied parasitic species either in blood or tissues. Results elucidated that; Myrrh oil significantly inhibit the growth at 1% of parasitic blood level for all bovine and equine piroplasm under the study. Parasitic regrowth was inhibited subsequently by viability test at 2 µg/mL for B. bigemina and B. bovis, and there was a significant improvement in the in vitro growth inhibition by myrrh oil when combined with DA, PYR, and luteolin. At the same time; mice treated with a combination of myrrh oil/DA showed a higher inhibition in emitted fluorescence signals than the group that challenged with 25 mg/kg of diminazene aceturate at 10 and 12 days post-infection. In conclusion, this study has recommended the myrrh oil to treat animal piroplasmosis, especially in combination with low doses of DA.

Inhibitory effects of pepstatin A and mefloquine on the growth of Babesia parasites

We evaluated the inhibitory effects of pepstatin A and mefloquine on the in vitro and in vivo growths of Babesia parasites. The in vitro growth of Babesia bovis, B. bigemina, B. caballi, and B. equi was significantly inhibited (P < 0.05) by micromolar concentrations of pepstatin A (50% inhibitory concentrations = 38.5, 36.5, 17.6, and 18.1 μM, respectively) and mefloquine (50% inhibitory concentrations = 59.7, 56.7, 20.7, and 4 μM, respectively). Furthermore, both reagents either alone at a concentration of 5 mg/kg or in combinations (2.5/2.5 and 5/5 mg/kg) for 10 days significantly inhibited the in vivo growth of B. microti in mice. Mefloquine treatment was highly effective and the combination treatments were less effective than other treatments. Therefore, mefloquine may antagonize the actions of pepstatin A against babesiosis and aspartic proteases may play an important role in the asexual growth cycle of Babesia parasites.

Development and evaluation of two nested PCR assays for the detection of Babesia bovis from cattle blood

We developed and evaluated two nested polymerase chain reaction (nPCR) assays for the diagnosis of Babesia bovis infection in cattle based on two membrane protein genes from B. bovis, BBOV_IV005650 (BV5650) and BBO_IV008970 (BV8970). The specificities and sensitivities of the tests were compared with B. bovis Rhoptery associated protein 1 gene (RAP-1) nPCR. The specificity of the tests was 100% for B. bovis DNA. The sensitivities of nPCR to B. bovis from the in vitro cultured parasites were as low as 10(-8)%, 10(-6)%, and 10(-7)% parasitemia for BV5650, BV8970, and RAP-1 nPCR, respectively. The nPCR detected as little as 1 fg genomic DNA per test for BV5650 and 100fg per test for both BV8970 and RAP-1 genes. For field applications, the sensitivity was evaluated to a total of 165 field samples from Ghana, Mongolia, Brazil and Japan. The nPCR assay of BV5650 was the most sensitive for the detection of B. bovis from the field samples. The BV5650 nPCR assay provides a good diagnostic tool for laboratory diagnostic assessment of B. bovis infection in cattle worldwide.

Evaluation of in vitro inhibitory effect of enoxacin on Babesia and Theileria parasites

Enoxacin is a broad-spectrum 6-fluoronaphthyridinone antibacterial agent (fluoroquinolones) structurally related to nalidixic acid used mainly in the treatment of urinary tract infections and gonorrhea. Also it has been shown recently that it may have cancer inhibiting effect. The primary antibabesial effect of Enoxacin is due to inhibition of DNA gyrase subunit A, and DNA topoisomerase. In the present study, enoxacin was tested as a potent inhibitor against the in vitro growth of bovine and equine Piroplasms. The in vitro growth of five Babesia species that were tested was significantly inhibited (P < 0.05) by micro molar concentrations of enoxacin (IC50 values = 33.5, 15.2, 7.5 and 23.2 μM for Babesia bovis, Babesia bigemina, Babesia caballi, and Theileria equi, respectively). Enoxacin IC50 values for Babesia and Theileria parasites were satisfactory as the drug is potent antibacterial drug with minimum side effects. Therefore, enoxacin might be used for treatment of Babesiosis and Theileriosis especially in case of mixed infections with bacterial diseases or incase of animal sensitivity against diminazin toxicity.

Gastrointestinal nematodes from buffalo in Minoufiya Governorate, Egypt with special reference to Bunostomum phlebotomum

Gastrointestinal nematodes cause massive economic losses as an important impediment to the development of animals around the world. This study aimed to investigate the microscopical diagnosis of nematode parasites of buffalo from Minoufiya, Egypt and molecular characterization of Bunostomum phlebotomum. We examined 390 fecal samples with floatation and fecal culture techniques to recognize different genera of nematodes. The results revealed B. phlebotomum (2.56%), Strongyloides papillosus (3.85%), Toxocara vitulorum (7.69%), Haemonchus sp. (1.28%), and Dictyocaulus viviparus (1.28%). The recovered eggs and larvae of nematodes were identified as well as the adults of B. phlebotomum. Age-wise, sex-wise, and seasonal prevalences of the recovered nematodes were recorded. Sequence analysis of the ITS-2 gene of B. phlebotomum was highly identical (99-100%) to sequences from Australia and China and occurred in the same clade with B. trigoncephalum. In conclusion, the study presented the coprological survey of gastrointestinal nematodes, and the genetic characterization of B. phlebotomum from Minoufiya Governorate, Egypt for the first time.

Infection rate and biochemical characterization of Cysticercus tenuicollis from sheep in Minoufiya governorate, Egypt

Cysticercus tenuicollis, the larval stage of Taenia hydatigenia, infects sheep and causes economic losses due to condemnation of infected organs. This study was designed to report the infection rate, risk factors, biochemical, and molecular characterization of Cysticercus tenuicollis in sheep from Ashmoun, Minoufiya, Egypt. The infection rate was 18%. The age was a risk factor for infection where there was a significant difference in infection rate between sheep more than 3 years and sheep under 3 years of age. There was no significant difference between infection in male and female groups. The liver had the highest organ distribution followed by omentum. Biochemical analysis of the cyst fluid showed some variations in the levels of ALT, AST, triglycerides, cholesterol, total protein, urea nitrogen, calcium, sodium, chromium, potassium than the levels identified in Algeria, Iraq, and Iran. PCR and sequence analysis of cox1 and ssrRNA showed that the sequences from Minoufiya, Egypt were highly identical to the related ones from several countries and confirmed the cyst is Cysticercus tenuicollis. This study reported the infection rate, risk factors, biochemical analysis, and molecular characterization of Cysticercus tenuicollis in sheep from Minoufiya, Egypt.

Infection rate and molecular characterization of Echidnophaga gallinacea in chickens from Matrouh Governorate, Egypt

Echidnophaga gallinacea is the sticktight flea of chickens. It causes dermatitis and ulcers in the skin and carries some disease-causing agents such as Rickettsia and Bartonella. This study was conducted to detect the infection rate and elucidate the molecular characterization of E. gallinacea in chickens from El-Dabaa City, Matrouh Governorate, Egypt. The fleas were collected from infected chickens and identified morphologically. The internal transcribed spacer-1 (ITS-1) gene PCR method was used for molecular characterization. Based on the morphology, the collected fleas were confirmed as E. gallinacea. The overall infection rate was 5%, with 4.5% in female and 10% in male chickens. ITS-1 PCR revealed a specific band of 488 bp. The ITS-1 gene sequence from Egypt occurred in the same phylogenetic clade as that from Cameroon, with a percentage identity of 98.47%.

Prevalence and molecular characterization of Hysterothylacium species infecting Pandora (Pagellus erythrinus) in the Mediterranean Sea of Egypt

Species of the genus Hysterothylacium are aquatic roundworms (nematodes) belonging to the family Raphidascarididae. Some species in this family are known to be associated with zoonotic diseases in humans after they consume their parasitic larvae in raw or undercooked fish. The aim of this research was to report the prevalence, morphology, and molecular characteristics of Hysterothylacium species in Pagellus erythrinus. A total of Two hundred fish were purchased from the fish market in Damanhour, Beheira Province, between December 2021 and November 2022 and subjected to examination. For molecular characterization, the internal transcribed spacer (ITS) region of nuclear ribosomal DNA and the mitochondrial cytochrome oxidase subunit 2 (COX-2) gene were used. Hysterothylacium species were morphologically described and identified from the intestine of Pagellus erythrinus in Beheira Province, Egypt. The PCR amplified 1087 bp and 629 bp of the target sequences of the ITS region and COX-2 gene, respectively. Sequence analysis revealed the Hysterothylacium thalassini species. The identified species provided novel biological data for the Hysterothylacium nematode in Pagellus erythrinus. The prevalence of Hysterothylacium species recovered from the intestine was 55%. The highest prevalence of 72% has been reported in summer compared to the lowest prevalence of 38% in the winter. Females had a higher prevalence of 61.8% than males, with 44.2%. The first detection, prevalence, and molecular characterization of H. thalassini in Pagellus erythrinus from Beheira Province, Egypt, was presented in this study.

Prevalence and molecular characterization of Ascaridia galli in chickens from Minoufiya Governorate, Egypt

Ascaridia galli causes weight loss, emaciation, anemia, decreased egg production, and sometimes, intestinal obstruction and death in birds, leading to economic losses in the poultry industry. This research aimed to record the occurrence of A. galli in free-range chickens at farmers' houses in three villages in Ashmoun City, Minoufiya Governorate, Egypt. Additionally, molecular characterization was conducted using internal transcribed spacer 1 (ITS-1) region PCR and sequence analysis. A total of 570 chickens from 570 small flocks, each ranging in size from 10 to 20 free-range chickens, were investigated for the presence of A. galli. DNA was extracted from 10 adult worms collected from Shoshai and Elmanil-Dowib villages and subjected to PCR amplification and sequence analysis. The overall occurrence of A. galli in Ashmoun City was 38 %, with Elmanil-Dowib village having the highest prevalence at 45 %. The oldest chickens, over one year old, had the highest occurrence rate at 56 %, while females showed a higher occurrence (44 %) than males (15 %). The highest occurrence was observed during winter (47 %). The mean intensity and abundance of A. galli in Ashmoun were 5.52 and 2.07, respectively. The ITS-1 sequences of A. galli from Ashmoun, Minoufiya, Egypt had up to 100 % identity and clustered within the same genetic clade as A. galli from Egypt, Poland, and Bangladesh. Haplotype and nucleotide diversity analyses revealed that the sequences from Ashmoun represent a single haplotype and show no nucleotide mutations. This study presents the first report of the occurrence and genetic characterization of A. galli in Baladi chickens in Ashmoun City, Minoufiya, Egypt, thereby enhancing the understanding of A. galli epidemiology in this district and developing effective control strategies.

Identification and Characterization of P0 Protein as a Vaccine Candidate Against Babesia divergens, Blood Parasite of Veterinary and Zoonotic Importance

The molecular identification and antigenic characterization of P0 protein in Babesia divergens, a blood parasite of veterinary and zoonotic importance, were carried out in this study for use in developing subunit vaccines against B. divergens infection. Recombinant protein encoding P0 (BdP0) was developed in Escherichia coli, and its antiserum was generated in mice for further molecular characterization. Anti-rBdP0 serum had a specific interaction with the corresponding legitimate B. divergens protein, as confirmed by Western blotting and indirect fluorescent antibody tests. ELISA was used to assess the immunogenicity of BdP0 in a group of 68 bovine field samples, and significant immunological reactivity was found in 19 and 20 positive samples of rBdp0 and B. divergens lysate, respectively. The in vitro growth of B. divergens cultures treated with anti-rBdP0 serum was significantly inhibited (p < 0.05). Furthermore, after 6 h of incubation with 2 mg/ml anti-rBdP0 serum, the ability of pre-incubated free merozoites to invade bovine erythrocytes was reduced by 59.88%. The obtained data suggest the possible use of rBdP0 as diagnostic antigen and may serve as a vaccine candidate against babesiosis caused by B. divergens either in animal or human.