Extruded urea levels in lamb supplementation in rainy tropical savanna conditions: the triad host-gastrointestinal nematodes-environment.

The objective of this study was to evaluate the influence of increasing levels of extruded urea (EU, Amireia®) in the diet of lambs naturally infected by gastrointestinal nematodes on the interactions in the host-pasture-soil components in edaphoclimatic conditions of the tropical rainy savanna. A total of 60 Texel lambs with a mean initial weight of 20.7 ± 0.87 and mean age of 2.5 ± 0.70 months were distributed in a completely randomized design, in five treatments consisting of different levels of EU supplementation viz., 0, 6, 12, 18, and 24 g 100 kg-1 live weight (LW). The performance of lambs, parasitological variables, gastrointestinal nematodes (NGIs), and larvae recovery in pasture and soil were evaluated. The highest animal performance was observed in animals that received 0 to 18 g kg-1 LW (146.0 g day-1) and the lowest in animals supplemented with 24 g kg-1 LW (81.0 g day-1) of EU. The body condition score (BCS) was similar in the animals (P > 0.05). Parasitic infection did not differ as a function of EU level (P > 0.05). Eggs of Haemonchus spp., Trichostrongylus spp., Cooperia spp., and Oesophagostomum spp. were found. The largest amount of larvae in the L1/L2 and L3 stages was recovered in the pastures occupied by the animals that received supplementation 0 g kg-1 LW of EU (750 larvae), the smallest in those that the animals received 6 g 100 kg-1 LW of EU (54 larvae). The presence of larvae in the L1/L2 stages changed significantly (P < 0.05) in the soil; in the other stages, it did not differ in the soil. Increasing levels of extruded urea do not influence the eggs per gram of feces (EPG) count. The 0 to 18 g 100 kg-1 LW level maintains animal performance, BCS and FAMACHA©. There is less dispersal of NGI larvae in pasture and soil when EU levels increase in the edaphoclimatic conditions of the rainy tropical savannah, which suggests that this supplement can be implemented in the diet of beef lambs, in addition to to be a lower cost nitrogen source.

Phenotypic and Target-Directed Screening Yields New Acaricidal Alternatives for the Control of Ticks.

Rhipicephalus microplus, the "common cattle tick", is the most important ectoparasite in livestock worldwide due to the economic and health losses it produces. This tick is a vector for pathogens of several tick-borne diseases. In Latin American countries, damages reach approximately USD 500 million annually due to tick infections, as well as tick-borne diseases. Currently, resistant populations for every chemical group of acaricides have been reported, posing a serious problem for tick control. This study aims to find new alternatives for controlling resistant ticks with compounds derived from small synthetic organic molecules and natural origins. Using BME26 embryonic cells, we performed phenotypic screening of 44 natural extracts from 10 Mexican plants used in traditional medicine, and 33 compounds selected from our chemical collection. We found 10 extracts and 13 compounds that inhibited cell growth by 50% at 50 µg/mL and 100 µM, respectively; the dose-response profile of two of them was characterized, and these compounds were assayed in vitro against different life stages of Rhipicephalus microplus. We also performed a target-directed screening of the activity of triosephosphate isomerase, using 86 compounds selected from our chemical collection. In this collection, we found the most potent and selective inhibitor of tick triosephosphate isomerase reported until now. Two other compounds had a potent acaricidal effect in vitro using adults and larvae when compared with other acaricides such as ivermectin and Amitraz. Those compounds were also selective to the ticks compared with the cytotoxicity in mammalian cells like macrophages or bovine spermatozoids. They also had a good toxicological profile, resulting in promising acaricidal compounds for tick control in cattle raising.

Delayed reduction of Anaplasma marginale parasitemia and packed cell volume normalization despite prolonged enrofloxacin treatment of cattle co-infected with Trypanosoma vivax.

Although co-infections of Trypanosoma vivax, Anaplasma spp., and Babesia spp. have been reported, knowledge gaps remain that need to be addressed. The present study evaluated the efficacy of enrofloxacin (7.5 mg/kg) against A. marginale in naturally infected cattle and cattle experimentally co-infected with T. vivax by observation of the variation in A. marginale parasitemia and packed cell volume (PCV) for 39 days. Bovines were distributed into two groups, each with six calves: T01 = animals immunosuppressed with dexamethasone and with latent anaplasmosis; T02 = animals immunosuppressed with dexamethasone, with latent anaplasmosis and experimentally co-infected with T. vivax on day 0 (D0). Animals of both groups were immunosuppressed with dexamethasone and received enrofloxacin (7.5 mg/kg) whenever mean values of parasitemia for A. marginale were ≥ 5% per group. Cattle of group T02 were also treated with isometamidium chloride (0.5 mg/kg) on D25. On D17 and D22 to D28 of the study, there was a higher (P ≤ 0.05) A. marginale parasitemia in animals of T02 than in those of T01. Animals of T01 required one enrofloxacin treatment to decrease A. marginale parasitemia, while those from T02 needed five treatments. From D5 to D37 of study, the mean values of PCV for calves from T02 were lower (P ≤ 0.05) than that for calves from T01. In conclusion, bovines co-infected T. vivax needed four more treatments with enrofloxacin to reduce A. marginale parasitemia and keep PCV values within reference standards.

Assessment of Babesia bovis 6cys A and 6cys B as components of transmission blocking vaccines for babesiosis.

BACKGROUND: Babesia bovis reproduces sexually in the gut of its tick vector Rhipicephalus microplus, which involves expression of 6cys A and 6cys B proteins. Members of the widely conserved 6cys superfamily are candidates for transmission blocking vaccines (TBV), but intricacies in the immunogenicity of the 6cys proteins in the related Plasmodium parasites required the identification of transmission blocking domains in these molecules for vaccine design. Hereby, the immunogenic efficacy of recombinant (r) B. bovis 6cys A and B proteins as a TBV formulation was studied. METHODS: The immunogenicity of r6cys A and 6cys B proteins expressed in a eukaryotic system was evaluated in a cattle immunization trial (3 immunized and 3 control calves). A B. bovis sexual stage induction in vitro inhibition assay to assess the ability of antibodies to block the production of sexual forms by the parasite was developed. RESULTS: Immunized cattle generated antibodies against r6cys A and r6cys B that were unable to block sexual reproduction of the parasite in ticks. Additionally, these antibodies also failed in recognizing native 6cys A and 6cys B and peptides representing 6cys A and 6cys B functional domains and in inhibiting the development of sexual forms in an in vitro induction system. In contrast, rabbit antibodies generated against synthetic peptides representing predicted B-cell epitopes of 6cys A and 6cys B recognized recombinant and native forms of both 6cys proteins as well as peptides representing 6cys A and 6cys B functional domains and were able to neutralize development of sexual forms of the parasite in vitro. CONCLUSIONS: These data, combined with similar work performed on Plasmodium 6cys proteins, indicate that an effective 6cys protein-based TBV against B. bovis will require identifying and targeting selected regions of proteins containing epitopes able to reduce transmission.

Innate and humoral immune parameters at delivery in colostrum and calves from heifers experimentally infected with Neospora caninum.

Neospora caninum is a leading cause of abortion in cattle worldwide. The study of the immune response against N. caninum is critical to understand its epidemiology, pathogenesis, diagnosis and, ultimately, in preventing and controlling bovine neosporosis. Herein, we determined the gene expression of innate immune components endosomal RNA-sensing TLRs, BMAP28 cathelicidin, TNF-α and IL-10 and characterized the variation in both IgG ratio and avidity at delivery in N. caninum-infected heifers challenged at day 210 of gestation, colostrum and their calves. Increased BMAP28 expression was observed not only in colostrum but also in peripheral blood mononuclear cells (PBMC) and umbilical cord of calves from N. caninum-infected heifers in comparison with mock-infected control group. In addition, statistically significant decrease of TLR7 and IL-10 expression levels were observed in umbilical cord, suggesting an attempt to avoid an exacerbated immune response against the parasite. At delivery, serum and colostrum samples from infected group evidenced specific IgG anti-N. caninum. Infected heifers showed IgG1/IgG2 ratios <1 and high avidity specific IgG. As expected, colostrum samples of these animals exhibited a high IgG1 concentration and elevated avidity values. Three out of four calves from N. caninum-infected heifers had specific IgG with IgG1/IgG2 ratios>1 and lower avidity values before colostrum intake. Interestingly, both IgG1/IgG2 ratios and avidity values increased in seropositive calves after colostrum intake. Overall, this study provides novel information on neonatal immunity in congenitally infected calves, which is essential to understand how the immune pathways could be manipulated or immune components could be employed in order to improve protection against neosporosis.

Development of an efficient antitick natural formulation for the control of acaricide-resistant ticks on livestock.

Animal production has a key role in global economic development and food security. Ticks, specifically Rhipicephalus microplus cause substantial economic and health impacts on more than eighty percent of the world cattle population. Though synthetic acaricides play a major role in tick management, their injudicious usage has caused environmental pollution and also promote the establishment of multi-acaricide resistant tick populations which is a matter of great concern. To provide an effective tool for controlling these resistant ticks, the present work was aimed to develop safe and inexpensive antitick natural formulations. Our bioprospection studies of Ageratum conyzoides plant established it as a species potentially having strong acaricidal activity due to the presence of potent acaricidal phyto-chemicals. To develop a suitable antitick natural formulation, 41 samples/fractions/formulations were prepared from the dry powder of the whole aerial part of the A. conyzoides plant using different techniques and delivery matrices. The strongest antitick effect was recorded for formulation ACF6, which demonstrated 87 ± 6% mean mortality with 57 % inhibition of oviposition in treated female ticks. Ticks treated with the ACF6 formulation showed a significant (p < 0.001) reduction in cuticular protein (1.238 ± 0.01 mg/mL) as compared to control ticks (2.928 ± 0.01 mg/mL) but no significant difference in chitin content of treated ticks and control ticks was observed. The formulation was found safe in a rat model as no significant differences in biochemical and haematological parameters among treated and control rats were noted. Histopathological studies indicated no sign of hepatocellular necrosis and no significant changes in the weights of liver and spleen was recorded. The overall in vivo efficacy of the formulation was 85 % for experimentally infested cattle with direct mortality of more than 80 % within 96 h post-application. The lethal effect of the formulation was in the form of drying and dead ticks 1-2 d after application. The developed formulation has the potential to be adopted as an alternative tick control measure in an ecofriendly manner.

Control of Rhipicephalus annulatus resistant to deltamethrin by spraying infested cattle with synergistic eucalyptus essential oil-thymol-deltamethrin combination.

The current study investigated the synergistic effect of combinations containing deltamethrin (D), Eucalyptus essential oil (E), and the thyme essential oil component thymol (T), against a field population of Rhipicephalus annulatus in Egypt that was characterized to be resistant to D. Solutions of T, E, or TE at concentrations of 1.25-5% were combined with 5% deltamethrin at different dilutions (0.25-2 mL/L). Results of the adult immersion test used to estimate the in vitro acaricidal activity of these combinations at 5% yielded LC50 values for D, E-D, T-D, and TE-D of 3.87 mL/L, 3.89 mL/L, 0.14 mL/L, and 0.05 mL/L, respectively. Biochemical analyses using whole-body homogenate of ticks from the in vitro tests revealed that the lowest acetylcholinesterase and glutathione peroxidase activity, and the maximum lipid peroxidation were recorded in ticks treated with 5% TE-D. Glutathione content significantly decreased (p ≤ 0.05) in all treated ticks. Three groups, each containing five cross breed cattle naturally infested with R. annulatus from the same area where resistance to D was detected, were sprayed twice at two-week intervals using 1 mL/L of 5% solutions of D, T-D, or TE-D. Overall efficacy of the D, T-D, and TE-D sprays by day 30 post-treatment was 21.6, 88.3, and 95 %, respectively. Ticks collected from infested cattle three days after treatment with the D spray deposited egg masses that were able to hatch, deposited small masses of eggs unable to hatch when exposed to the T-D spray, and laid few eggs that didn't hatch when sprayed with the TE-D combination. Values for liver and kidney function parameters were comparable in cattle before and after treatment with the combination sprays tested. The TE-D spray overcame the insensitivity to D of this R. annulatus population in Egypt, which also highlighted the significant synergistic effect of thymol on the acaricidal activity of deltamethrin observed in vitro. Acaricidal activity of the TE-D combination apparently has deleterious effects on multiple tick systems involving inhibition of acetylcholinesterase, increased lipid peroxidation, and oxidative stress. These findings document that combinations of natural and synthetic products can be part of integrated management solutions to the problem with widespread resistance to pyrethroids like deltamethrin in populations of cattle ticks, including R. annulatus, around the world.

Current status of prevalence and risk factors associated with liver fluke Fasciola hepatica in cattle raised in different altitudinal regions of Colombia.

Fasciola hepatica is a trematode parasite with a worldwide distribution that affects mammals, including humans, and is considered a major food safety and public health problem. A research was conducted in three hundred eighty-five livestock farms located in different altitudinal regions of Colombia between February 2017 and March 2018 with the aim to determine the coprological prevalence, seroprevalence (SP) and risk factors associated with liver fluke F. hepatica. A total of 5620 fecal sample were collected from cattle and processed using sedimentation technique. Additionally, 597 blood samples were collected and processed by an ELISA test. The coprological prevalence of F. hepatica in animals and herds was 6.4% and 38.4%, respectively. Regarding the prevalence by municipalities, there was statistical association (P < .05), indicating that the prevalence was higher in those municipalities above 2000 masl (meters above sea level). Regarding risk factors, cattle raised in municipalities at 2000 to 3000 masl showed about 4 (OR = 3.96 [CI95% 3.1-5]; P < .05) times higher probability for infection than those raised at lower altitude. Cattle from 2 to 3 year of age, showed almost 4 times (OR = 3.7[CI95% 2.5-5.4]; P < .05), increased infection risk. Females and dairy breeds showed almost 2 (OR = 1.9 [CI95% 1.3-2.6]; P < .05) and 10 times (OR = 10 [CI95% 7.8-12.8]; P < .05), respectively, increased infection risk. The presence of antibodies anti- F. hepatica (SP = 37.8%; [CI95% 35.8-39.7]; P < .05) in cattle of the region under study is confirmed, which suggests an endemic behavior of this parasitosis. The present study provides current information on the prevalence of F. hepatica in different altitudinal regions of Colombia, and these findings could be useful for designing new holistic control measures for the liver fluke F. hepatica infection.

A holistic model to assess risk factors of fasciolosis in Ankole cattle.

In recent decades, remote sensing (RS) technology and geographical information systems (GIS) were increasingly used as tools for epidemiological studies and the control of zoonotic diseases. Fasciolosis, a zoonotic disease caused by a trematode parasite (Fasciola spp.), is a good candidate for the application of RS and GIS in epidemiology because it is strongly influenced by the environment, i.e. the habitat of the intermediate host. In this study, we examined variables which may increase the fasciolosis risk of Ankole cattle in the degraded and overgrazed Mutara rangelands of north-eastern Rwanda. The risk variables considered included three environmental variables (normalized difference vegetation index, NDVI; normalized difference moisture index, NDMI; normalized difference water index, NDWI), two landscape metric variables (rangeland proportion, building density), two geological variables (poorly-drained soil proportion, elevation) and three animal husbandry variables (herd size, adult proportion and the body condition score). Fasciola spp. prevalence was used as the dependent variable, sampling season as a fixed factor and four principal components (PCs, condensed from the ten risk variables) as covariates in a univariate General Linear Model. Fasciola spp. prevalence was positively correlated to rangeland proportion, cattle herd size in rural areas, adult proportion and individual body condition. Moreover, high Fasciola spp. prevalence was found in densely vegetated areas with high moisture (high values of NDVI and NDMI), in combination with large proportions of poorly-drained soil at low elevations. Future investigations should focus on increased sampling across the Mutara rangelands to prepare a predictive, spatial fasciolosis risk map that would help to further improve sustainable land-use management.

Rhipicephalus microplus (acari: Ixodidae): Clinical safety and potential control by topical application of cottonseed oil (Gossypium sp.) on cattle.

The present study was performed to determine the acaricidal activity of the cottonseed oil (CSO) against cattle tick Rhipicephalus microplus. CSO was analyzed using Gas Chromatograph with high-resolution Mass Spectrometer (GC-HRMS) to identify the presence of active compounds. In vitro bioassays were performed using larval packet test (LPT) and adult immersion test (AIT) by taking different concentrations of CSO (i.e. 0.1, 0.5, 1.5, 2.5, 5, 7.5, 10 and 12.5%). In vivo acaricidal activity of CSO was evaluated by its topical application on red Sahiwal calves for 144 h. Clinical safety of CSO was evaluated by performing skin irritancy test and examination of hematological profile of calves'. GC-HRMS analysis of CSO revealed the presence of many fatty acids including oleic acid, lauric acid, palmitic acid, stearic acid and other components. Results exhibited that all the concentrations of CSO were effective in reducing the number of ticks and their growth. However, CSO at concentrations of 10% (CSO7) and 12.5% (CSO8) exhibited 100% mortality of R. microplus larvae and adults in LPT and AIT, respectively. In vivo acaricidal assay revealed that CSO7 and CSO8 shown 85% and 89% inhibition of ticks, respectively on calves after 144 h as compared to the control group. CSO was clinically safe on calves' skin with mild erythema up to 20 min. Hematological profile of calves revealed no sign of toxicity after treatment with CSO. Thus, CSO can be used as an alternative and safe drug therapy against R. microplus.

The potential of Allium sativum and Cannabis sativa extracts for anti-tick activities against Rhipicephalus (Boophilus) microplus.

The efficacy of Allium sativum and Cannabis sativa against Rhipicephalus microplus ticks was evaluated using the adult immersion and the larval packet test. In addition, an in silico approach was utilized by performing a docking study in order to identify the active ingredients from both plants. Results showed a comparatively high lethal effect of A. sativum and C. sativa on egg laying (index of egg laying = 0.26 and 0.24, respectively), egg hatching (33.5 and 37.1, respectively), and total larval mortality (100%, both), at 40 mg/mL. When applied to cattle which had been inoculated with larvae ticks, it was observed that a 45% solution of both herbal extracts significantly reduced the number of ticks by 96 h post treatment. We analyzed in silico 27 known active molecules from both plants and identified in the PubChem database to explore the hypothesis that the effect found on ticks was based on inhibition of acetylcholinesterase (AChE). Vitamin E and cannabidiol are the most potent AChE inhibitors with docking scores of -15.85 and -14.38, respectively. Based on these findings, we conclude that A. sativum and C. sativa may potentially be used for the control of R. microplus, and should be further investigated as a potential supplement to or replacement of synthetic acaricides.

Marrubium vulgare L.: A Phytochemical and Pharmacological Overview.

Marrubium vulgare is a plant with high bioactive potential. It contains marrubiin, a labdane diterpene that is characteristic for this genus, as well as a complex mixture of phenolic compounds. According to numerous studies, M. vulgare acts as a good antioxidant agent, and due to this, it could potentially be useful in treatments of cancer, diabetes mellitus, and liver diseases. In addition, its anti-inflammatory, wound-healing, antihypertensive, hypolipidemic, and sedative potential are discussed. Apart from that, its antimicrobial activity, especially against Gram+ bacteria, fungi, herpes simplex virus, and parasites such as Toxoplasma gondii, Trichomonas vaginalis, and Plasmodium berghei-berghei was recorded. Additionally, it could be used as a chicken lice repellent, herbicide, and natural insecticide against mosquito larvae and natural molluscicide. In veterinary medicine, M. vulgare can be used as an anthelmintic against the eggs and larvae of bovine strongyles parasites, and as an antibiotic against bovine mastitis caused by resistant bacterial strains. Due to the mentioned benefits, there is a tendency for the cultivation of M. vulgare in order to ensure high-quality raw material, but more firm scientific evidence and well-designed clinical trials are necessary for the well-established use of M. vulgare herb and its preparations.

Vibrational Spectroscopic Based Approach for Diagnosing Babesia bovis Infection.

Babesia bovis parasites present a serious and significant health concern for the beef and dairy industries in many parts of the world. Difficulties associated with the current diagnostic techniques include the following: they are prone to human error (microscopy) or expensive and time-consuming (polymerase chain reaction) to perform. Little is known about the biochemical changes in blood that are associated with Babesia infections. The discovery of new biomarkers will lead to improved diagnostic outcomes for the cattle industry. Vibrational spectroscopic technologies can record a chemical snapshot of the entire organism and the surrounding cell thereby providing a phenotype of the organism and the host infected cell. Here, we demonstrate the applicability of vibrational spectroscopic imaging techniques including Atomic Force Microscopy Infrared (AFM-IR) and confocal Raman microscopy to discover new biomarkers for B. bovis infections. Furthermore, we applied Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) to detect B. bovis in red blood cells (RBCs). Based on changes in the IR spectral bands, with ATR-FTIR in combination with Partial Least Squares-Discriminant Analysis we were able to discriminate infected samples from controls with a sensitivity and specificity of 92.0% and 91.7%, respectively, in less than 2 min, excluding sample extraction and preparation. The proposed method utilized a lysis approach to remove hemoglobin from the suspension of infected and uninfected cells, which significantly increased the sensitivity and specificity compared to measurements performed on intact infected red blood cells (intact infected RBC, 77.3% and 79.2%). This work represents a holistic spectroscopic study from the level of the single infected RBC using AFM-IR and confocal Raman to the detection of the parasite in a cell population using ATR-FTIR for a babesiosis diagnostic.

In vitro acaricidal activity of Cymbopogon citratus, Cymbopogon nardus and Mentha arvensis against Rhipicephalus microplus (Acari: Ixodidae).

The chemical composition and acaricidal activity of plant-derived essential oils was assessed against Rhipicephalus microplus ticks. The essential oils of Mentha arvensis, Cymbopogon citratus and C. nardus were assessed for acaricidal activity against Rhipicephalus microplus. Essential oils (EO) of plants were separated by hydrodistillation (three times) and analyzed using gas chromatography - mass spectrometer (GC-MS). For bioassays, engorged females of R. microplus were exposed to C. citratus and C. nardus EO at 2%, 3%, 4% and 5% concentrations; and to M. arvensis EO at 1%, 3%, and 5% for 5 min. The weight egg mass, nutrient index (N.I), egg production index (E.P.I), hatching and control rate were evaluated. Non-feed larvae of R. microplus were exposed to essential oils with 0.25%, 0.5%; 1%; 1.5% and 2% concentrations; the mortality rate was measured after 48 h. Only engorged females presented reduced biological activities (oviposition, E.P.I) after exposure to M. arvensis at 3%, when in comparison to both positive and negative controls. The hatchability of R. microplus larvae ranged from 66.9% (after exposure to C. nardus EO at 5%) to 99.2% (positive control). The nutrition index was lower (46.6%) for the exposure to M. arvensis EO at 5%. M. arvensis at 3% and 5% concentrations was significantly efficient for engorged females when compared to control (53.7% and 47.5%, respectively). C. citratus EO at 1%, 1.5% and 2% concentrations yielded better results in the larval packet test, causing 100% mortality. Nonetheless, C. nardus and M. arvensis EO at 2% yielded 66% and 39% mortality, respectively. The study showed that M. arvensis presented potential for the control of R. microplus engorged females while C. citratus and C. nardus presented potential as a larvicide.

Repellency effect of Pilocarpus spicatus A. St.-Hil essential oil and nanoemulsion against Rhipicephalus microplus larvae.

Rhipicephalus microplus, the cattle tick, is a major cause of economic losses in bovine production. Due to the widespread acaricidal resistance to commercially available products, as well as their toxicity and environmental impact, alternative control methods are required. Nanoformulations produced from plant extracts as bioactive substances are very promising as innovative acaricidal agents. Thus, the aim of this study was to evaluate the in vitro repellent activity of Pilocarpus spicatus essential oil and its nanoemulsion against R. microplus, using larval repellent test (RT). The essential oil was extracted by hydrodistillation, using a Clevenger-type apparatus. The nanoemulsion was prepared with 5% essential oil, 5% tween 80, and 90% water, using the phase inversion method (50 mg/mL). Limonene was the major component (46.8%) of the essential oil, as determined by gas chromatography-mass spectrometry (GC/MS) and confirmed by flame ionization detection (GC/FID). According to the RT results, the essential oil had a repellent activity greater than 69%, from concentrations of 3.12 mg/mL (69.81 ± 10%) to 50 mg/mL (98.10 ± 0.6%), whereas the nanoemulsion at 50 mg/mL presented repellent activities of 97.14 ± 1.37% and 97.89 ± 0.52% 6 and 10 h after treatment, respectively. These values regarding to total repellency were very close to those calculated for mortality corrected by Abbott's formula. The phase inversion method preserved the chemical and physical characteristics of the essential oil since both reached an equal repellent effect at the same concentration. Therefore, P. spicatus essential oil and nanoemulsion had excellent repellent activities against R. microplus larvae, demonstrating its potential for future use as an alternative for tick control.

Importance of colostrum IgG antibodies level for prevention of infection with Cryptosporidium parvum in neonatal dairy calves.

Cryptosporidiosis is one of the most common zoonosis worldwide, causing intestinal infection to both humans and livestock. The purpose of this study was to assess whether the level of anti-C. parvum IgG antibodies transferred through colostrum from dams to newborn calves impacts the susceptibility to cryptosporidiosis. A number of 50 dams and their healthy newborns were included in the study. Colostrum samples were collected within 12 h after birth and anti-C. parvum IgG antibody levels were determined by single radial immunodiffusion. The health condition of the newborns was daily monitored, and fecal samples were collected at first diarrheic episode of a calf. In all dams, the anti-C. parvum IgG antibody concentration in colostrum varied between 570 and 4070 mg/dl; in dams who gave birth to calves with diarrhea and were C. parvum-positive, the antibody concentration in colostrum varied between 680 and 3680 mg/dl (Table 1). The point-biserial correlation showed a negative correlation between the levels of anti-C. parvum antibodies and manifestation of clinical cryptosporidiosis (r=-0.425). Our findings highlight the importance of IgG levels in colostrum received by neonatal calves during their first day of life for prevention of C. parvum infection.

Drug screening of food and drug administration-approved compounds against Babesia bovis in vitro.

Babesia (B.) bovis is one of the main etiological agents of bovine babesiosis, causes serious economic losses to the cattle industry. Control of bovine babesiosis has been hindered by the limited treatment selection for B. bovis, thus, new options are urgently needed. We explored the drug library and unbiasedly screened 640 food and drug administration (FDA) approved drug compounds for their inhibitory activities against B. bovis in vitro. The initial screening identified 13 potentially effective compounds. Four potent compounds, namely mycophenolic acid (MPA), pentamidine (PTD), doxorubicin hydrochloride (DBH) and vorinostat (SAHA) exhibited the lowest IC50 and then selected for further evaluation of their in vitro efficacies using viability, combination inhibitory and cytotoxicity assays. The half-maximal inhibitory concentration (IC50) values of MPA, PTD, DBH, SAHA were 11.38 ± 1.66, 13.12 ± 4.29, 1.79 ± 0.15 and 45.18 ± 7.37 µM, respectively. Of note, DBH exhibited IC50 lower than that calculated for the commonly used antibabesial drug, diminazene aceturate (DA). The viability result revealed the ability of MPA, PTD, DBH, SAHA to prevent the regrowth of treated parasite at 4 × and 2 × of IC50. Antagonistic interactions against B. bovis were observed after treatment with either MPA, PTD, DBH or SAHA in combination with DA. Our findings indicate the richness of FDA approved compounds by novel potent antibabesial candidates and the identified potent compounds especially DBH might be used for the treatment of animal babesiosis caused by B. bovis.

Effect of essential oils on cattle gastrointestinal nematodes assessed by egg hatch, larval migration and mortality testing.

The efficacy of eight essential oils (EOs) (Solidago canadensis, Eucalyptus globulus, Pelargonium asperum, Ocimum basilicum, Thymus vulgaris, Mentha piperita, Cymbopogon citratus and Cymbopogon martinii) against gastrointestinal nematodes (GINs) was evaluated using eggs collected from naturally infected cattle and cultured infective larvae (L3). The larvae species cultured from the faecal samples and subjected to two in vitro tests were Haemonchus spp. (55.5%), Trichostrongylus spp. (28.0%), Cooperia spp. (15.0%) and Oesophagostomum spp. (1.5%). The genus of EO Cymbopogon (C. citratus and C. martinii) showed the highest anthelmintic activity at the dose of 8.75 mg/ml, for the egg hatch, the larval migration and mortality assays. All of the EOs tested reduced egg hatching to rates <19.0%, compared to the controls (water and water + Tween 20) that had rates >92.0%. Cymbopogon citratus and C. martinii treatments resulted in 11.6 and 8.1% egg hatch, had the lowest migration of larvae through sieves, 60.5 and 54.9%, and the highest mortality rates, 63.3 and 56.3%, respectively. Dose-response tests showed that EO from C. citratus had the lowest larval LC50 and migration inhibition concentration (IC50) values of 3.89 and 7.19 mg/ml, respectively, compared to two other EOs (C. martinii and O. basilicum). The results suggest that EOs from the genus Cymbopogon can be interesting candidates for nematode control in cattle, although it may prove challenging to deliver concentrations to the gastrointestinal tract sufficient to effectively manage GINs.

Acaricidal activity of plant-derived essential oil components against Psoroptes ovis in vitro and in vivo.

BACKGROUND: Treatment of Psoroptes ovis in cattle is limited to topical acaricides or systemic treatment with macrocyclic lactones. Treatment failure of macrocyclic lactones has been reported. The aim of this study was to evaluate a potential alternative treatment against P. ovis. METHODS: The acaricidal activity against P. ovis of four plant-derived essential oil components, i.e. geraniol, eugenol, 1,8-cineol and carvacrol, was assessed in vitro and in vivo. In vitro contact, fumigation and residual bioassays were performed. In addition, 12 Belgium Blue cattle were artificially infested and treated topically once a week for three successive weeks with carvacrol in Tween-80 (treatment group) or with Tween-80 alone (control). The efficacy of carvacrol was determined by the reduction in lesion size and mite counts. Six additional animals were topically treated with carvacrol to assess local adverse reactions. RESULTS: Three components showed a concentration-dependent acaricidal activity in a contact assay, with LC50 of 0.56, 0.38 and 0.26% at 24 h for geraniol, eugenol, and carvacrol, respectively. However, 1,8-cineol showed no activity at any of the tested concentrations in a contact bioassay. In a fumigation bioassay, carvacrol killed all mites within 50 min after treatment, whereas geraniol, eugenol and 1,8-cineol needed 90 to 150 min. Following a 72 h incubation period in a residual bioassay, carvacrol killed all mites after 4 h of exposure to LC90, while geraniol and eugenol killed all mites only after 8 h exposure. Based on these results, carvacrol was further assessed in vivo. Mite counts in the treatment group were reduced by 98.5 ± 2.4% at 6 weeks post-treatment, while in the control group the mite population had increased. Topical application of carvacrol only caused mild and transient erythema 20 min after treatment. No other side effects were observed. CONCLUSIONS: Considering the strong acaricidal activity of carvacrol in vitro and in vivo and the mild and transient local side effects, carvacrol shows potential as an acaricidal agent in the treatment of P. ovis in cattle.

The Anthelmintic Effects of Medicinal Plant Extracts Against Paramphistome Parasites, Carmyerius spatiosus.

INTRODUCTION: Paramphistomosis is a disease caused by the rumen flukes which cause an acute gastroenteritis and anemia with high mortality particularly in young ruminants. MATERIALS AND METHODS: In this study, we have investigated the anthelmintic effect of medicinal plant extracts from leaves and heartwoods of Cassia siamea L., roots of Plumbago zeylanica L. and Plumbago indica L., and leaves of Terminalia catappa L. against Carmyerius spatiosus. RESULTS: The highest anthelminthic effect on the flukes after 24 h of exposure was found in heartwood ethyl acetate extract of C. siamea (LC50 = 374.30; LC90 = 749.03 ppm), root n-butanol extract of P. zeylanica (LC50 = 1005.12; LC90 = 2411.55 ppm), root hexane, ethyl acetate, and n-butanol extract of P. indica (LC50 = 34.38, 211.34, 506.92; LC90 = 64.09, 496.05, 934.86 ppm), and leaf n-butanol and water extract of T. catappa (LC50 = 487.17, 470.28; LC90 = 913.27, 848.23 ppm). When observed by scanning electron microscopy, the tegument showed similar sequence of morphological changes after treatments with all plant extracts, comprising of swelling of ridges and folds, blebbing, rupturing of the blebs, erosion, lesion and disruption of the tegument. CONCLUSION: This study is the first report on the anthelmintic activity of plant extracts to C. spatiosus; therefore, these plant extracts are highly effective in the elimination of adult rumen flukes.