Prevalence and risk factors associated with Tritrichomonas foetus infection in cattle in the state of Paraíba, Brazil

Evaluation of the susceptibility of Tritrichomonas foetus to extracts of Lantana camara (Verbenaceae) by flow cytometry

Bovine Trichomonosis (BT), a sexually transmitted disease endemic in countries with extensive cattle farming and natural service, is one of the most common causes of reproductive failure. 5-nitroimidazoles and their derivatives are used for its treatment, mainly metronidazole. The emergence of drug resistance mechanisms and treatment failures raise the need to investigate the effectiveness of new active compounds that contribute to parasite control. In this regard, extracts of Lantana camara (Verbenacea) have shown high biocidal potential against isolates of Trypanosoma cruzi and Leishmania braziliensis in vitro assays, although their effect on Tritrichomonas foetus has not been demonstrated yet. The available information on in vitro susceptibility of trichomonicidal drugs comes from the use of a diversity of methodologies and criteria, especially the observation of parasite motility under the optical microscope to assess their viability. Recently, in our laboratory, the use of flow cytometry has been described for the first time as a rapid and efficient method to evaluate the viability of T. foetus against metronidazole. The present study aimed to evaluate the cytostatic effect of L. camara extracts against T. foetus isolates by flow cytometry. Under aerobic conditions, IC50 values of 22.60 µg/mL were obtained on average. Under anaerobic conditions, the IC50 oscilated around 29.04 µg/mL. The results obtained allowed describing the susceptibility exhibited by these protozoa, being a valuable information for the development of potential BT treatments.

Molecular prevalence and phylogenetic confirmation of bovine trichomoniasis in aborted cows in Iraq

Background and Aim

Bovine trichomoniasis, caused by Tritrichomonas foetus, is a venereal disease that is distributed in many countries, including Iraq. Compared with other abortive infectious diseases, prevalence of T. foetus is expected to be relatively low in the field by veterinarians. This study aimed to estimate the prevalence of T. foetus in aborted cows by conventional polymerase chain reaction (PCR) and phylogenetic analysis of local T. foetus isolates was documented in the National Center for Biotechnology Information as the first sequenced isolates from Iraq.

Materials and Methods

Vaginal fluids were collected from 62 aborted cows and examined by PCR. Data were reported for the following parameters: Vital signs (body temperature and respiratory and pulse rates), age (<4, 4-8, and >8 years), reproductive health status (premature calving, embryonic death, pyometra, and healthy newborn), breed (pure or crossbred), type of breeding (natural or artificial), bull-to-cow ratio (1:<10, 1:10-20, and 1:>20), contact of cow with bull(s) from other farmers (yes or no), and contact with stray animals (dogs and cats).

Results

A total of 20.97% of aborted cows were positive for T. foetus. Phylogenetic analysis for 10 positive local T. foetus isolates demonstrated high identity with the Thai (MN560972.2) and Chinese (MH115435.1) isolates, with an identity range of 98.8%-99.5% and 98.6%-99.3%, respectively. Clinical data showed that the vital signs differed insignificantly between cows positive and negative for T. foetus. Prevalence and risk of infection increased significantly in <4-year-old, early calving, embryonic death, crossbred, and naturally inseminated cows that had direct contact with bulls from other farmers, and contact with stray animals. Fetal pneumonia and death of premature calves were significant among positive aborted fetuses.

Conclusion

Tritrichomonas foetus is highly prevalent in aborted cows in Iraq and phylogenetic analysis demonstrated an identity between the local and global isolates, that is, Thai and Chinese, of cats.

Tritrichomonas Foetus as a Causative Agent of Tritrichomonosis in Different Animal Hosts

Tritrichomonas foetus is a protozoan parasite that has been traditionally identified as a cause of reproductive tract disease in cattle and gastrointestinal tract infection in cats. Moreover, T. foetus is also well known as a commensal of the nasal cavity, intestines, and stomach in swine. In this review we describe T. foetus as a pathogen dangerous to more than one animal host, diagnostic and taxonomic aspects of this infection, and the extent to which isolates from different hosts share genetic identity.

In Vitro Susceptibility to Metronidazole of Tritrichomonas foetus Bovine Isolates from Argentina

BACKGROUND

Tritrichomonas foetus is the etiologic agent of the sexually transmitted disease Bovine Trichomonosis (BT). In Argentina, BT is endemic and represents a relevant health problem that causes reproductive inefficiency in cattle and large economic losses. Metronidazole is the drug of choice in the treatment of BT. Treatment has been associated with a temporary resolution of the clinical signs but is not able to control the disease. In recent years, the apparition of in vivo and in vitro aerobic and anaerobic resistance leading to ineffective treatments has been reported.

AIMS

Thus, the aim of the present study was to explore the susceptibility of six different isolates of T. foetus under aerobic (AC) and anaerobic (ANC) conditions.

RESULTS AND DISCUSSION

Six isolates of T. foetus were obtained from samples of preputial smegma of bovine origin. Values of minimum lethal concentration and minimum inhibitory concentration were higher than those observed in other works and represent current data in Argentina and provide information to establish new treatment protocols.

Flow cytometry evaluation of in vitro susceptibility of bovine isolates of Tritrichomonas foetus to metronidazole

Bovine Trichomonosis, an endemic sexually transmitted disease in countries with extensive livestock and natural service, represents one of the most common causes of reproductive failure. 5-nitroimidazoles and their derivatives are used for its treatment, mainly metronidazole (Mz). The emergence of resistance mechanisms adopted by the parasites against the drug and failure of the treatments suggest the need to investigate susceptibility and obtain current values. The available information of in vitro susceptibility of these drugs comes from the use of a diversity of methodologies and criteria, especially observation of the mobility of the parasite under the optical microscope to evaluate its viability. These techniques are arduous and time consuming and lead to a subjective assessment dependent on the operator, the methodology used, and the morphology adopted by the protozoan. In this sense, flow cytometry has proven to be a fast and efficient method to evaluate viability in other protozoa. The aim of this study was to evaluate the in vitro susceptibility of six bovine isolates of Tritrichomonas foetus to Mz in aerobic (AC) and anaerobic (ANC) conditions by means of the calculation of the 50% inhibitory concentration (IC₅₀), by flow cytometry, and also to analyze minimum lethal concentration (MLC) by means of recovery tests post-treatment in vitro. IC₅₀ values ranged from 1.06 to 1.25 μM in ANC and from 1.44 to 3.03 μM in AC, these being the only ones reported at 48 h for these protozoa. With respect to MLC at 48 h, the results were from 3.67 to 7.35 μM in ANC, and from 7.35 to 14.7 μM for AC, where two isolates (Tf0 and Tf2) for AC and one (Tf2) for ANC showed higher values than those described in the literature. Flow cytometry has proven to be an effective, rapid and objective methodology and very useful in susceptibility tests. The data obtained through these tests allow us to describe the susceptibility exhibited by these protozoa, this being valuable information when establishing dosages in Mz treatments.