In vitro anti-Trichomonas gallinae effects of Ziziphus vulgaris L. and Camellia sinensis (L.) Kuntze extracts

BACKGROUND

Trichomonas gallinae is a parasite that causes canker and severe loss and death, especially in young pigeons. Metronidazole (MTZ) is the recommended drug for treating avian trichomoniasis. Due to drug resistance, non-chemical alternatives, such as medicinal plant extracts, are also considered possible therapies for this disease.

OBJECTIVES

This study compares the antitrichomonal effects of MTZ with extracts of Camellia sinensis and Ziziphus vulgaris on T. gallinae in vitro.

METHODS

Samples of T. gallinae were taken from infected pigeons. Multi-well plates with different concentrations (5, 10, 25, 50 and 100 µg/mL) of plant extracts were used for the in vitro study.

RESULTS

The minimum inhibitory concentration (MIC) of C. sinensis extract was 25 µg/mL over 24 h, compared to 50 µg/mL for MTZ. The MIC value of the Z. vulgaris extracts was 50 µg/mL.

CONCLUSIONS

The results suggest that the extracts of Z. vulgaris and C. sinensis, as potential natural agents, could have anti-avian trichomoniasis properties. This study also shows that MTZ, C. sinensis and Z. vulgaris are equally effective in preventing the growth of T. gallinae trophozoites in the culture.

Drug resistance patterns and genotype associations of Trichomonas gallinae in meat pigeons (Columba livia): insights from Guangdong Province, China

Avian trichomoniasis, caused by the protozoan parasite Trichomonas gallinae, is a prevalent and economically significant disease in pigeons. This study investigated the drug resistance of T. gallinae isolates in Guangdong Province, China. The results revealed that 25.3% (20/79) of the isolates were resistant to one or more of the four nitroimidazole drugs tested, namely, metronidazole, dimetridazole, secnidazole, and tinidazole. Secnidazole elicited the highest resistance rate (19.0%; 15/79), followed by tinidazole (17.7%; 14/79), metronidazole (17.7%; 14/79), and dimetridazole (13.9%; 11/79). An enormous majority of the resistant isolates (70.0%; 14/20) exhibited resistance to multiple drugs. Additionally, the resistance rate was significantly higher in isolates from birds aged < 30 days (53.3%; 8/15) than in those from older birds (23.1%; 12/52). Moreover, no drug resistance was detected in female pigeons. The genotype of the isolated strain was also associated with drug resistance. Specifically, 50.0% (15/30) of ITS-B genotypes exhibited resistance to drugs, while only 10.2% (5/49) of ITS-A genotypes demonstrated resistance. This study also found the growth characteristics of different Trichomonas isolates to be influenced by their genotypes and initial inoculum concentrations. These findings underscore the urgent need for effective measures to control and prevent drug-resistant T. gallinae infections in pigeons, thus ensuring the stable development of the pigeon industry.

Identification of new drug candidates against Trichomonas gallinae using high-throughput screening

Trichomonas gallinae is a protozoan parasite that is the causative agent of trichomoniasis, and infects captive and wild bird species throughout the world. Although metronidazole has been the drug of choice against trichomoniasis for decades, most Trichomonas gallinae strains have developed resistance. Therefore, drugs with new modes of action or targets are urgently needed. Here, we report the development and application of a cell-based CCK-8 method for the high-throughput screening and identification of new inhibitors of Trichomonas gallinae as a beginning point for the development of new treatments for trichomoniasis. We performed the high-throughput screening of 173 anti-parasitic compounds, and found 16 compounds that were potentially effective against Trichomonas gallinae. By measuring the median inhibitory concentration (IC50) and median cytotoxic concentration (CC50), we identified 3 potentially safe and effective compounds against Trichomonas gallinae: anisomycin, fumagillin, and MG132. In conclusion, this research successfully established a high-throughput screening method for compounds and identified 3 new safe and effective compounds against Trichomonas gallinae, providing a new treatment scheme for trichomoniasis.

A retrospective study of pigeon herpesviral infection in domestic pigeons in California (1991-2014) and literature review

We characterized naturally occurring pigeon herpesvirus (PiHV; Columbid alphaherpesvirus 1) infection in domestic pigeons in California. We retrieved and analyzed 62 pathology reports produced between 1991 and 2014 at the California Animal Health and Food Safety Laboratory System. In 56 of the cases, the diagnosis of PiHV infection was established based on histopathology, either alone (44 cases) or combined with virus isolation (VI; 8), transmission electron microscopy (TEM; 3), or PCR (1); in the remaining 6 cases, the diagnosis was established based on VI (5 cases) or TEM (1) alone. PiHV infection affected 1 system in 34, 2 in 16, and ≥3 systems in 6 cases; data were not available for the remaining 6 cases. Most commonly affected was the digestive system (55 cases), followed by the respiratory tract (5) and lymphoid system (2). The liver (39 cases), crop (17), and esophagus (14) were the organs affected most commonly. Many affected cells often bore single eosinophilic intranuclear inclusion bodies. PiHV infection was a secondary diagnosis or incidental finding in 35 cases. Most (55) cases had 1 (21), or up to 4 (34), other concurrent infections; the most common concurrent infections were pigeon circoviral infection (26), trichomonosis (24), aspergillosis (11), and colibacillosis (10).

Supplementation of exogenous bile acids improve antitrichomonal activity and enhance intestinal health in pigeon (Columba livia)

The study investigated the effects of supplementation of bile acids in drinking water on antitrichomonal activity, growth performance, immunity and microbial composition of pigeon. A total of 180 pairs of White King parent pigeons were randomly assigned to 5 treatments of 6 replications with 6 pairs of parent pigeons and 12 squabs in each replicate. The control (CON) group drank water without any additions. The metronidazole (MTZ) group drank water with 500 μg/mL metronidazole for 7 d and without any additions in other days. The else groups drank water with 500, 750, and 1,250 μg/mL bile acid (BAL, BAM, BAH) for 28 d. The results showed that Trichomonas gallinae (T. gallinae) in MTZ, BAL, BAM, and BAH groups were lower than that in CON group at 14, 21, and 28 d of parent pigeons (P < 0.05) and at 21 and 28 d of squabs (P < 0.05). Albumin and alanine transaminase in CON group were higher than those in MTZ, BAL, and BAH groups (P < 0.05). The levels of soluble CD8 were higher in MTZ and BAH groups compared with CON group (P < 0.05). The lesions in oral mucosa, thymus, liver, and spleen tissues of CON group could be observed. Abundance-based coverage estimator (ACE) index in BAH group was higher than that in CON and MTZ groups. Simpson index in CON and BAH groups was higher than MTZ group (P < 0.05). Lactobacillus was the highest colonized colonic bacteria in genera that were 77.21, 91.20, and 73.19% in CON, MTZ, and BAH, respectively. In conclusion, drinking water supplemented with 500, 750, and 1,250 μg/mL bile acid could inhibit growth of T. gallinae in both parent pigeons and squabs. Squabs infected with T. gallinae in control group had higher mortality rate and more serious tissue lesions. Squabs in bile acids treated group had more sCD8 in serum and abundant intestinal morphology. Bile acids could be an efficient drinking supplements to inhibit T. gallinae and improve pigeon adaptive immunity and intestinal health.

Anti-Trichomonas gallinae activity of essential oils and main compounds from Lamiaceae and Asteraceae plants

Trichomonas gallinae is a flagellated protozoan that parasitizes the upper digestive tract of various bird species and causes avian trichomonosis. The emergence of resistant strains to the standard treatment, based on nitroimidazoles, increases the need to find alternative therapies. In this study, 36 essential oils (EOs) from Lamiaceae and Asteraceae plant families were tested against T. gallinae trophozoites using the 3-(4,5-dimethylthiazol-2-yl-)-2,5-dipheniltetrazolium bromide (MTT) reduction assay. Among them, EOs from distinct species of Lamiaceae, including the genera Lavandula, Salvia, Thymus, Origanum, and Satureja were the ones reporting better anti-trichomonal activity, and were selected for further analysis, including chemical composition and in vitro assays. The chemical composition of the selected EOs was determined by gas chromatography followed by mass spectrometry and 19 pure compounds were tested against the protozoa, according to their higher abundance in the active EOs. Pure compounds which displayed the highest activity against T. gallinae trophozoites, ordered by highest to lowest activity, were α and β-thujones, camphene, β-pinene, linalyl acetate, thymol, 4-terpineol, γ-terpinene, α-pinene, p-cymene, D-fenchone and β-caryophyllene. A dose dependent effect was observed in most of the EOs and pure compounds tested. The toxicity test conducted in eukaryotic cell cultures with the anti-trichomonal active pure compounds showed that β-caryophyllene, camphene, α-pinene, and β-pinene were slightly toxic for Vero cells, and the selectivity index was calculated. Based on the anti-trichomonal activity and the absence of cytotoxicity results, natural products from Lamiaceae plants could be useful as alternative therapy against avian trichomonosis, mainly those containing linalyl acetate, thymol, 4-terpinenol, γ-terpinene, p-cymene and D-fenchone.

Antitrichomonal activity of metronidazole-loaded lactoferrin nanoparticles in pigeon trichomoniasis

In recent years, increasing attention has been paid to the novel drug delivery systems to reduce the dose of the drug and avoid side effects. Metronidazole has been used for many years in the treatment of anaerobic bacterial and protozoal infections. Nanolactoferrin, a newly developed antibacterial agent originated from lactoferrin, is applied both as an active therapeutic and a drug nanocarrier. The present study describes the development and characterization of metronidazole-loaded lactoferrin nanoparticles (nano-MTZ) as well as reports their antitrichomonal activity on Trichomonas gallinae, the protozoal causative agent of pigeon trichomoniasis. The activity of the nano-MTZ is compared with the regular metronidazole formulation (MTZ) under in vitro and in vivo conditions. Additionally, cytotoxicity of the nano-MTZ to fibroblast cell line and possible hepatotoxicity in treated pigeons were evaluated. Nano-MTZ was prepared based on the thermal treatment method and the average size and surface charge of the dispersion were 30.6 nm and - 44.6 mv, respectively. No significant cytotoxicity was noted for the nano-MTZ in comparison to the MTZ. Loading efficiency in nano-MTZ was calculated as 55%. In vitro susceptibility results demonstrated 24 h 90% lethal concentration values of 4.23 and 6.64 µg/mL for MTZ and nano-MTZ, respectively. Oral treatment of the pigeons experimentally infected with T. gallinae resulted in the earlier eradication of the infection in the nano-MTZ-treated pigeons. No adverse effects on the liver function have been observed for the nano-MTZ. These findings suggest that nanolactoferrin is a promising platform for the development of novel MTZ formulations with improved antitrichomonal activity.

Antiprotozoal and anthelmintic activity of zinc oxide nanoparticles

Nanomaterials represent a wide alternative for the treatment of several diseases that affect both human and animal health. The use of these materials mainly involves trying to solve the problem of resistance that pathogenic organisms acquire to conventional drugs. A well-studied example that represents a potential component for biomedical applications is the use of zinc oxide (ZnO) nanoparticles (NPs). Its antimicrobial function is related, especially the ability to generate/induce ROS that affects the homeostasis of the pathogen in question. Protozoa and helminths that harm human health and the economic performance of animals have already been exposed to this type of nanoparticle. Thus, through this review, our goal is to discuss the state-of-the-art effect of ZnO NPs on these parasites.

Comparative pharmacokinetics of metronidazole in healthy and Trichomonas gallinae infected pigeons (Columba livia, var. domestica)

1. This study investigated the pharmacokinetics of metronidazole after intravenous (i.v.) and oral administration to healthy and experimentally Trichomonas gallinae-infected pigeons, and determined the in vitro antiprotozoal activity of metronidazole against T. gallinae.2. Twelve pigeons which were experimentally infected to T. gallinae and twelve healthy pigeons received metronidazole at the dose of 25 mg/kg by oral or i.v. administration. Serial blood sampling was used for pharmacokinetic analysis. The metronidazole minimum lethal concentration (MLC) and the concentration killing 50% of the trophozoites (LC₅₀) in the culture media were determined.3. In vitro data showed that the 24 h LC₅₀ and MLC of metronidazole were 0.31 and 25 µg/ml, respectively. In vivo results showed no statistical differences between pharmacokinetics in infected and non-infected pigeons for both routes of administration. The area under the curve was statistically higher after the i.v. administration in both infected and healthy pigeons. The mean oral bioavailability was similar in the infected (83.8%) and the healthy (81.5%) birds.4. In conclusion, the pharmacokinetics of metronidazole in pigeons was not affected by experimentally-induced trichomoniasis. Despite in vitro susceptibility testing, which showed probable resistance of the isolated T. gallinae to metronidazole, five-day oral treatment of infected pigeons with 25 mg/kg metronidazole twice a day resulted in total eradication of trophozoites recovered in crop lavage of infected birds.

In vitro assessment of anti-Trichomonas effects of Zingiber officinale and Lavandula angustifolia alcoholic extracts on Trichomonas gallinae

Trichomonas gallinae is a parasite that acts as a canker-causing agent and leads to significant loss and mortality, especially in young birds. Metronidazole is the approved drug used for the treatment of trichomoniasis. A non-chemical alternativess such as medical plant extracts are also used to treat this disease due to drug resistance. This study aimed to assess in vitro antitrichomonal effects of Lavandula angustifolia and Zingiber officinale extracts on T. gallinae compared with metronidazole. The T. gallinae samples were obtained from infected pigeons. Multi-well plates filled with different concentrations (5.00, 10.00, 25.00, 50.00, and 100 μg mL^-1) were used to perform in vitro analysis. The Z. officinale extract's minimum inhibitory concentration (MIC) in the 24-hr period was 25.00 μg mL^-1, while it was 50.00 μg mL^-1 for metronidazole. The MIC value obtained for L. angustifolia extract in 24-hr was 50.00 μg mL^-1. The results indicated that the extracts of Z. officinale and L. angustifolia could act as potential natural agents against trichomoniasis. Furthermore, this study delineated the equal efficiency of L. angustifolia and Z. officinale with that of metronidazole in inhibiting the growth of Trichomonas gallinae trophozoites in culture media.