Establishment and application of TaqMan real-time PCR method for detection of Theileria annulata resistant to buparvaquone

Tropical theileriosis is a tick-borne disease that caused by Theileria annulata, and leads to substantial economic impact in endemic area. Distinguishes to other piroplasms, Theileria is the only eukaryotic parasite could transform mammalian leukocytes. At present, buparvaquone is the most effective drug used for treatment of Theileria infection. However, frequently reported of failure treatment with buparvaquone for some T. annulata isolates. Mutation of TaPIN1 was reported to be the direct reason for failure of buparvaquone treatment. Through in vitro culture, a T. annulata isolate with a TaPIN1 mutation that is similar to the reported strain was recently identified in China. In order to understand the distribution of Theileria with mutation of TaPIN1 in China, here we developed a TaqMan probe-based real-time PCR technology to detect the mutated TaPIN1 gene. The specificity, sensitivity and reproducibility of the established TaqMan Real-time PCR method were evaluated, and field cattle blood samples collected from Xinjiang Uyghur Autonomous Region were used to test its application. Among 1683 samples, 335 samples were confirmed positive for T. annulata by traditional PCR method and 34 samples were positive for buparvaquone-resistant. The TaPIN1 gene of those 34 samples was sequenced and analyzed with the published gene sequences from NCBI database. The results showed that the sequence obtained from the present study has good consistency with those published sequences. In conclusion, the TaqMan probe-based real-time PCR targeting T. annulata mutated TaPIN1 gene was successfully established and can be used to detect clinical samples to investigation of buparvaquone-resistant parasites in Xinjiang region quickly and accurately, which will be useful for guiding clinical medicine application.

Modulation of CXCL10 activity as a therapeutic target of ocular toxoplasmosis in diabetic mice

Ocular toxoplasmosis is likely the most common cause of infectious posterior uveitis worldwide. CXCL10 chemokine has an important role in the maintenance of the T-cell response and the control of Toxoplasma gondii in the eye during chronic infection. Drugs that can modulate the chemokine activity could be effective against the parasite. In this work, CXCL10 local retinal expression was investigated in a diabetic mouse model with ocular toxoplasmosis for the first time. In addition, the efficacy of naphthoquinones and quinolones was compared to spiramycin (SP) in treating the infection and modulating the chemokine expression. Our results revealed that chloroquine (CQ) achieved the best results regarding the reduction of cerebral cyst burden (84.36%), improving the retinal histopathological changes, cellular infiltrates, and vasculitis significantly (P < 0.005), and balancing the strong CXCL10 expression caused by the infection. Buparvaquone-treated mice showed a significant percentage of reduction of brain cysts (76.25%), moderate improvement of histopathology, and mild to moderate CXCL10 expression. While SP showed the least efficacy against the parasite in the eye in the form of mild improvement of histopathological changes and downregulation of retinal chemokine expression with the least reduction rate of cerebral parasitic burden (57%). In conclusion, Optimal control of pathogens probably needs a balanced immune response with an optimum expression of chemokines. So, targeting the modulation of retinal CXCL10 may eventually be beneficial in the management of ocular toxoplasmosis plus its potential to act as a marker for predictive local immunological response during the infection.

Theileria annulata Induced Bilateral Ocular Signs in Cattle and Its Successful Therapeutic Management: A Case Report

Bovine tropical theileriosis is one of the potentially fatal disease of dairy cattle, which is caused by hemoparasite Theleria annulata. About seven years old cross-bred cow was presented with complaint of pyrexia, inappetance, lacrimation and ocular swelling since last 5 days. The clinical examination showed elevated rectal temperature (39.4 °C), mild enlarged pre-scapular lymph nodes, bilateral bulging of temporal fossa, protruded pale and icteric conjunctivae of the eyes with lacrimation and presence of ticks on body. The case was suspected for haemoprotozoan disease. Blood and serum sample were collected for hematological, blood smear examination and molecular examination (PCR), and biochemical analysis respectively. Microscopic examination of blood smear revealed intra-erythrocytic signet ring shaped periplasm of Theileria annulata. Hemato-biochemical examination revealed anemia, hypoproteinemia, hypoalbuminemia and jaundice. Further, PCR assay was done using T. annulata-specific primer pair, Cyto b1 gene targeting the amplicon of 312 bp showed specific band on Gel-electrophoresis. Therapeutic regimen was started with Buparvaquone @ 2.5 mg/kg body weight IM single dose followed by Oxytetracycline @ 10 mg/kg body weight IV in 500 ml of NS for 5 days and Prednisolone @ 0.25 mg/kg body weight IM for 3 days along with supportive therapy. The cattle well responded to the therapy and complete regression of ocular signs was observed within one week of treatment.

Genetic characterisation of the Theileria annulata cytochrome b locus and its impact on buparvaquone resistance in bovine

Control of tropical theileriosis, caused by the apicomplexan Theileria annulata, depends on the use of a single drug, buparvaquone, the efficacy of which is compromised by the emergence of resistance. The present study was undertaken to improve understanding of the role of mutations conferring buparvaquone resistance in T. annulata, and the effects of selection pressures on their emergence and spread. First, we investigated genetic characteristics of the cytochrome b locus associated with buparvaquone resistance in 10 susceptible and 7 resistant T. annulata isolates. The 129G (GGC) mutation was found in the Q₀₁ binding pocket and 253S (TCT) and 262S (TCA) mutations were identified within the Q₀₂ binding pocket. Next, we examined field isolates and identified cytochrome b mutations 129G (GGC), 253S (TCT) and 262S (TCA) in 21/75 buffalo-derived and 19/119 cattle-derived T. annulata isolates, providing evidence of positive selection pressure. Both hard and soft selective sweeps were identified, with striking differences between isolates. For example, 19 buffalo-derived and 7 cattle-derived isolates contained 129G (GGC) and 253S (TCT) resistance haplotypes at a high frequency, implying the emergence of resistance by a single mutation. Two buffalo-derived and 12 cattle-derived isolates contained equally high frequencies of 129G (GGC), 253S (TCT), 129G (GGC)/253S (TCT) and 262S (TCA) resistance haplotypes, implying the emergence of resistance by pre-existing or recurrent mutations. Phylogenetic analysis further revealed that 9 and 21 unique haplotypes in buffalo and cattle-derived isolates were present in a single lineage, suggesting a single origin. We propose that animal migration between farms is an important factor in the spread of buparvaquone resistance in endemic regions of Pakistan. The overall outcomes will be useful in understanding how drug resistance emerges and spreads, and this information will help design strategies to optimise the use and lifespan of the single most drug use to control tropical theileriosis.

Oral administration of buparvaquone nanostructured lipid carrier enables in vivo activity against Leishmania infantum

Leishmaniasis, a neglected tropical disease, is prevalent in 98 countries with the occurrence of 1.3 million new cases annually. The conventional therapy for visceral leishmaniasis requires hospitalization due to the severe adverse effects of the drugs, which are administered parenterally. Buparvaquone (BPQ) showed in vitro activity against leishmania parasites; nevertheless, it has failed in vivo tests due to its low aqueous solubility. Though, lipid nanoparticles can overcome this holdback. In this study we tested the hypothesis whether BPQ-NLC shows in vivo activity against L. infantum. Two optimized formulations were prepared (V1: 173.9 ± 1.6 nm, 0.5 mg of BPQ/mL; V2: 232.4 ± 1.6 nm, 1.3 mg of BPQ/mL), both showed increased solubility up to 73.00-fold, and dissolution up to 83.29%, while for the free drug it was only 2.89%. Cytotoxicity test showed their biocompatibility (CC50 >554.4 µM). Besides, the V1 dose of 0.3 mg/kg/day for 10 days reduced the parasite burden in 83.4% ±18.2% (p <0.05) in the liver. BPQ-NLC showed similar leishmanicidal activity compared to miltefosine. Therefore, BPQ-NLC is a promising addition to the limited therapeutic arsenal suitable for leishmaniasis oral administration treatment.

Shape mediated splenotropic delivery of buparvaquone loaded solid lipid nanoparticles

Buparvaquone (BPQ)-loaded asymmetric solid lipid nanoparticles (SLN) prepared by a modified nanoprecipitation method were evaluated for splenotropic drug delivery. BPQ SLN exhibited an average particle size of 650.28 ± 6.75 nm with polydispersity index ≤ 0.3, entrapment efficiency of 96.57 ± 0.190%, and drug loading of 24.63 ± 0.042%. Scanning electron microscopy (SEM) revealed elongated particles with flattened and rounded edges. Aspect ratio, an important determinant of asymmetricity of the BPQ SLN, measured as the ratio of average length (1143 ± 0.083 nm) to width (419 ± 0.031 nm) was found to be 2.727 ± 0.19. The hemolytic potential of 10.86 ± 0.04% and good serum stability suggested feasibility for intravenous administration. ^99mTc-labeled BPQ SLN revealed high radiolabeling efficiency (> 95%) and good stability. Intravenous administration in mice revealed > 75% accumulation in the reticuloendothelial system organs. The percent radioactivity per gram of organ was in the order spleen > kidney > lungs > liver > lymph nodes, with high splenic accumulation and significantly lower concentration in the liver. An astoundingly high spleen/liver ratio with a maximum of 11.94 ± 1.37 at 3 h, which confirmed high splenic uptake is attributed to Kupffer cell bypass. Other factors contributing to splenotropy are the rigidity and the low molecular weight of the lipid in the BPQ SLN which enabled translocation of the particles into the splenic pulp. Our study proposes asymmetric BPQ SLN as a promising splenotropic delivery system for improved efficacy in theileriosis, a spleen resident infection.

Topical buparvaquone nano-enabled hydrogels for cutaneous leishmaniasis

Leishmaniasis is a neglected disease presenting cutaneous, mucosal and visceral forms and affecting an estimated 12 million mostly low-income people. Treatment of cutaneous leishmaniasis (CL) is recommended to expedite healing, reduce risk of scarring, prevent parasite dissemination to other mucocutaneous (common with New World species) or visceral forms and reduce the chance of relapse, but remains an unmet need. Available treatments are painful, prolonged (>20 days) and require hospitalisation, which increases the cost of therapy. Here we present the development of optimised topical self-nanoemulsifying drug delivery systems (SNEDDS) loaded with buparvaquone (BPQ, a hydroxynapthoquinone from the open Malaria Box) for the treatment of CL from New World species. The administration of topical BPQ-SNEDDS gels for 7 days resulted in a reduction of parasite load of 99.989 ± 0.019% similar to the decrease achieved with intralesionally administered Glucantime® (99.873 ± 0.204%) in a L. amazonensis BALB/c model. In vivo efficacy was supported by ex vivo permeability and in vivo tape stripping studies. BPQ-SNEDDS and their hydrogels demonstrated linear flux across non-infected CD-1 mouse skin ex vivo of 182.4 ± 63.0 μg cm^-2 h^-1 and 57.6 ± 10.8 μg cm^-2 h^-1 respectively localising BPQ within the skin in clinically effective concentrations (227.0 ± 45.9 μg and 103.8 ± 33.8 μg) respectively. These levels are therapeutic as BPQ-SNEDDS and their gels showed nanomolar in vitro efficacy against L. amazonensis and L. braziliensis amastigotes with excellent selectivity index toward parasites versus murine macrophages. In vivo tape stripping experiments indicated localisation of BPQ within the stratum corneum and dermis. Histology studies confirmed the reduction of parasitism and indicated healing in animals treated with BPQ-SNEDDS hydrogels. These results highlight the potential clinical capability of nano-enabled BPQ hydrogels towards a non-invasive treatment for CL.

Exposure to ambient air causes degradation and decreased in vitro potency of buparvaquone and parvaquone

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Buparvaquone and parvaquone are used to treat livestock infected with Theileria spp.

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Air exposure had a significant impact on the stability of buparvaquone and parvaquone.

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Parvaquone was more stable than buparvaquone.

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Drug degradation was related with loss of potency by an in vitro viability assay.

Buparvaquone and parvaquone are hydroxynaphthoquinone compounds commonly used to treat livestock infected with Theileria species such as T. parva and T. annulata. In many (sub)tropical regions, chromatic changes in medicines can result from extreme environmental conditions and improper drug storage or handling, raising the possibility of drug degradation and loss of potency. We evaluated the effects of UV light, elevated temperature, and atmospheric air on the stability and potency of both buparvaquone and parvaquone by using a combination of high performance liquid chromatography (HPLC) and a T. equi based in vitro parasite growth inhibition assay (to measure potency). Aliquots (1 ml; 3 replicates per treatment) of each compound were subjected to a variety of treatments that varied in duration and intensity followed by HPLC and potency assays. Exposure to ambient air for 50 days was correlated with a significant loss of potency for both buparvaquone (4535%, P <  0.05) and parvaquone (247%, P <  0.05), while elevated temperature (37°C) and UV light exposure (24 h) had no significant impact (P >  0.05). The decrease in potency of both buparvaquone and parvaquone correlated with drug degradation (r = -0.74 and -0.88, respectively) as measured by HPLC. In practice, if there is headspace present in the vial, then ambient air will invariably enter the vial and contribute to degradation of these compounds. Such degradation may contribute to increasing drug resistance, economic losses for farmers, and animal welfare concerns for animals that are treated for Theileria infections.

Co-delivery of buparvaquone and polymyxin B in a nanostructured lipid carrier for leishmaniasis treatment

OBJECTIVES

This study aimed to describe the preparation and in vitro evaluation of a surface-modified nanostructured lipid carrier (NLC) using chitosan and dextran for co-delivery of buparvaquone (BPQ) and polymyxin B (PB) against leishmaniasis.

METHODS

The NLC was prepared using high-pressure homogenisation. Polymyxin B binding and surface modification with biopolymers were achieved by electrostatic interaction. In vitro cytotoxicity was assessed in mouse peritoneal macrophages, and leishmanicidal activity in amastigotes of Leishmania infantum.

RESULTS

The performance attributes of BPQ-NLC, BPQ-NLC-PB[A^-] (anionic) and BPQ-NLC-PB[C⁺] (cationic) were respectively: Z-average 173.9 ± 1.6, 183.8 ± 4.5 and 208.8 ± 2.6 nm; zeta potential -19.6 ± 1.5, -20.1 ± 1.1 and 31.1 ± 0.8 mV; CC₅₀ 583.4 ± 0.10, 203.1 ± 0.04 and 5.7 ± 0.06 μM; IC₅₀ 229.0 ± 0.04, 145.7 ± 0.04 and 150.5 ± 0.02 nM. The NLC in vitro leishmanicidal activity showed up to 3.1-fold increase when compared with free BPQ (P <  0.05, α = 0.05).

CONCLUSIONS

The developed NLC proved to be a promising formulation with which to overcome the drawbacks of current leishmaniasis treatment by the co-delivery of two alternative drugs and a macrophage targeting modified surface.

Evidence of multiple point mutations in Theileria annulata cytochrome b gene incriminated in buparvaquone treatment failure

Drug resistance is one of the emerging and re-emerging epidemics affecting both veterinary and public health sectors. Buparvaquone provides the most satisfactory means in the treatment of bovine tropical theileriosis. However, recently there has been widespread reports of development of resistance of Theileria annulata to buparvaquone. To investigate the situation in Sudan where bovine tropical theileriosis is endemic, fifty blood samples from T. annulata-positive cattle. were used for DNA extraction, PCR and cytochrome b gene nucleotide sequencing. Analysis of the two buparvaquone binding site regions Q₀₁ (130-148) and Q₀₂ (244-266), revealed three non- synonymous mutations at codon 146; alanine (GCT) to threonine (ACT) within the Q₀₁ region across all 50 isolates and the other mutation at codon 129; serine (AGC) to glycine (GGC) in 18 isolates which is very close to the Q₀₁ binding site. However, we documented another mutation at position 227; valine (GTG) to methionine (ATG) close to the close to the Q₀₂ binding site, in three isolates with mutation at codon 129. We concluded that this study has provided evidence of point mutations in the cytochrome b gene of T. annulata that might be associated with buparvaquone treatment failure in Sudan.

A comprehensive review on past, present and future aspects of canine theileriosis

Canine theileriosis is a notorious tick borne piroplasmid infection of wild and domestic canines. The causative agent has not yet been accurately classified. PCR studies revealed that causative agent resembles to Theileria genus and thus provisionally named as Theileria annae. The other Theileria species reported in canines is Theileria annulata, Theileria equi and unnamed Theileria specie. This emergent canine infection is considered to be endemic in most of the European countries. However in Asia this disease has not been reported till date. The vectors responsible for transmission of this disease have not been determined. It has been suggested that DNA of Theileria annae has been detected in hard tick Ixodes hexagonus in Northwestern Spain and several other tick species. Clinically canine theileriosis is characterized by severe weakness, fever, hemoglobinuria and anemia. Recently atovaquone or buparvaquone plus azithromycin therapy showed better clinical efficacy. This comprehensive review is intended to summarize the current knowledge on prevalence and epidemiology of canine theileriosis in different countries of the world and associated tick vectors.

Antiprotozoal treatment of canine babesiosis

Canine babesiosis is a tick-borne disease caused by several Babesia spp. which have different susceptebility to anti-protozoal drugs. A few drugs and drug combinations are used in the treatment of canine babesiosis often without complete parasite elimination leaving treated dogs as carriers which could relapse with clinical disease and also transmit infection further. Although the large form canine babesial species Babesia canis, Babesia vogeli and Babesia rossi are sensitive to the aromatic diamidines imidocarb dipropionate and diminazene aceturate, small form species such as Babesia gibsoni, Babesia conradae and Babesia vulpes (Theileria annae) are relatively resistant to these drugs and are treated with the combination of the hydroxynaphthoquinone atovaquone and the antibiotic azithromycin. Azithromycin and other antibiotics that have anti-protozoal properties target the apicoplast, a relict plastid found in protozoa, and exert a delayed death effect. The triple combination of clindamycin, diminazene aceturate and imidocarb dipropionate is also effective against B. gibsoni and used to treat atovaquone-resistant strains of this species. Novel drugs and the synergistic effects of drug combinations against Babesia infection should be explored further to find new treatments for canine babesiosis.

Buparvaquone therapy in a rock pigeon infected with Haemoproteus columbae showing torticollis

A clinical Haemoproteus columbae infection in a two months rock pigeon was diagnosed on the basis of outward signs and blood smear examination. The clinical signs suggestive of pigeon malaria were anorexia, depression, inability to fly, circling movements and episodes of torticollis. The characteristic halter shaped gametocytes were seen, in thin blood smear, encircling the nucleus of erythrocytes. Buparvaquone therapy, two intramuscular injections at the rate of 5 mg/kg at 72 h interval, was successful. Supplementation of multivitamin helped in speedy recovery and clinical signs along with uncommon torticollis, completely disappeared in one week.

A rare case of Theileria annulata induced corneal opacity in a calf

A 10 months old male cross-bred calf was presented in OPD Medicine, Referral Veterinary Polyclinic, ICAR-Indian Veterinary Research Institute, Izatnagar with the history of anorexia, impaired vision, heavy tick infestation and diarrhoea for the last 1 week. The clinical examination revealed enlarged pre-scapular lymph nodes, prominent cloudiness in eyes and exophthalmos. The presence of Koch blue bodies in biopsied lymph nodes and a PCR assay confirmed it to be bovine tropical theileriosis associated with unique corneal opacity. Treatment with buparvaquone at a dose of 2.5 mg/kg i.m. two doses 48 h apart was successful and typical ocular manifestations completely subsided after 2 weeks of therapy.

Theileria annulata induced brisket oedema in a bull and its successful treatment

In the present case, jugular vein engorgement and oedema of the brisket region which mimic the signs of pseudopericarditis due to theileriosis in a bull was reported. An adult Ongole crossbred bull with history of weakness, anorexia and oedema at brisket region was referred to Teaching Veterinary Clinical Complex, College of Veterinary Science, Proddatur. Physical examination revealed the presence of ticks over the body, right and left prescapular lymphadenopathy and oedema at brisket region. Blood examination revealed the presence of piroplasms in erythrocytes, schizont in lymphocytes, anaemia and lymphopenia. Bull was treated with injection buparvaquone along with supportive medications. By the 3rd week of therapy improvement was noticed by disappearance of brisket oedema and recurrence was not noticed during the 8  months of observation.

Efficacy, safety and tolerance of imidocarb dipropionate versus atovaquone or buparvaquone plus azithromycin used to treat sick dogs naturally infected with the Babesia microti-like piroplasm

BACKGROUND

Piroplasmosis caused by the Babesia microti-like piroplasm (Bml) is increasingly being detected in dogs in Europe. Sick dogs show acute disease with severe anaemia associated with thrombocytopenia with a poor response to current available drugs. This study assesses the safety and tolerance of three treatments and compares their efficacy over a full year of follow up in dogs naturally infected with Bml.

METHODS

Fifty-nine dogs naturally infected with Bml were randomly assigned to a treatment group: imidocarb dipropionate (5 mg/kg SC, 2 doses 14 d apart) (IMI); atovaquone (13.3 mg/kg PO q 8 h, 10 d)/azithromycin (10 mg/kg PO q 24 h, 10 d) (ATO); or buparvaquone (5 mg/kg IM, 2 d apart)/azithromycin (same dosage) (BUP). Before and after treatment (days 15, 45, 90 and 360), all dogs underwent a physical exam, blood tests and parasite detection (blood cytology and PCR). Clinical efficacy was assessed by grading 24 clinical and 8 clinicopathological signs from low to high severity.

RESULTS

Before treatment, most dogs had severe regenerative anaemia (88.13%) and thrombocytopenia (71.4%). On treatment Day 45, clinical signs were mostly reduced in all dogs, and by Day 90, practically all dogs under the ATO or BUP regimen were clinically healthy (76.4 and 88%, respectively). Highest percentage reductions in laboratory abnormalities (82.04%) were detected in animals treated with ATO. Over the year, clinical relapse of Bml was observed in 8 dogs (8/17) treated with IMI. However, on Day 360, these animals had recovered clinically, though clinicopathological abnormalities were still present in some of them. Parasitaemia was PCR-confirmed on Days 90 and 360 in 47.05 and 50% of dogs treated with ATO, 68 and 60.08% with BUP, and 94.1 and 73.3% with IMI, respectively. Even after 360 days, 13.3% of the dogs treated with IMI returned a positive blood cytology result.

CONCLUSIONS

IMI showed the worse clinical and parasitological, efficacy such that its use to treat Bml infection in dogs is not recommended. The treatments ATO and BUP showed better efficacy, though they were still incapable to completely eliminate PCR-proven infection at the recommended dose. All three treatments showed good tolerance and safety with scarce adverse events observed.

In-vitro sensitivity of Pakistani Leishmania tropica field isolate against buparvaquone in comparison to standard anti-leishmanial drugs

In this study, in vitro anti-leishmanial activity of buparvaquone was evaluated against promastigotes and intracellular amastigotes of Pakistani Leishmania tropica isolate KWH23 in relation to the current standard chemotherapy for leishmaniasis (sodium stibogluconate, sodium stibogluconate, amphotericin B and miltefosine). For buparvaquone, mean % inhibition in intracellular amastigotes at four different concentrations (1.35 µM, 0.51 µM, 0.17 µM and 0.057 µM) was 78%, 44%, 20% and 14% respectively, whereas, against promastigotes it was 89%, 77%, 45% and 35% respectively. IC50 values calculated to estimate the anti-leishmanial activity of buparvaquone against intra-cellular amastigotes and promastigotes was 0.53 µM (95% C.I. = 0.32-0.89) and 0.15 µM (95% C.I. = 0.01-1.84) respectively. Amphotericin B was the most potent in-vitro drug tested, with an IC50 of 0.075 µM (95% C.I. = 0.006-0.907) against promastigotes, and 0.065 µM (95% C.I. = 0.048-0.089) against intra-cellular amastigotes. Amphotericin B was more cytotoxic against THP1 cells, with an IC50 of 0.15 µM (95% C.I. = 0.01-0.95) and an apparent in-vitro therapeutic index of 2.0, than was buparvaquone, with an IC50 of 12.03 µM (95% C.I. = 5.36-26.96) against THP1 cells and a therapeutic index of 80.2. The study proposes that buparvaquone may be further investigated as a candidate drug for treatment of cutaneous leishmaniasis.

Buparvaquone is active against Neospora caninum in vitro and in experimentally infected mice

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Buparvaquone inhibits proliferation of Neospora caninum at nanomolar concentrations.

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In vitro, the drug acts mainly parasitostatic.

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Parasiticidal effects occur at µmolar concentrations after extended periods of time.

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Buparvaquone acts slowly as evidenced by transmission electron microscopy.

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Buparvaquone prevents clinical signs of acute neosporosis in mice.

The naphthoquinone buparvaquone is currently the only drug used against theileriosis. Here, the effects of buparvaquone were investigated in vitro and in an experimental mouse model for Neospora caninum infection. In 4-day proliferation assays, buparvaquone efficiently inhibited N. caninum tachyzoite replication (IC₅₀ = 4.9 nM; IC₁₀₀ = 100 nM). However, in the long term tachyzoites adapted and resumed proliferation in the presence of 100 nM buparvaquone after 20 days of cultivation. Parasiticidal activity was noted after 9 days of culture in 0.5 µM or 6 days in 1 µM buparvaquone. TEM of N. caninum infected fibroblasts treated with 1 µM buparvaquone showed that the drug acted rather slowly, and ultrastructural changes were evident only after 3–5 days of treatment, including severe alterations in the parasite cytoplasm, changes in the composition of the parasitophorous vacuole matrix and a diminished integrity of the vacuole membrane. Treatment of N. caninum infected mice with buparvaquone (100 mg/kg) either by intraperitoneal injection or gavage prevented neosporosis symptoms in 4 out of 6 mice in the intraperitoneally treated group, and in 6 out of 7 mice in the group receiving oral treatment. In the corresponding controls, all 6 mice injected intraperitoneally with corn oil alone died of acute neosporosis, and 4 out of 6 mice died in the orally treated control group. Assessment of infection intensities in the treatment groups showed that, compared to the drug treated groups, the controls showed a significantly higher parasite load in the lungs while cerebral parasite load was higher in the buparvaquone-treated groups. Thus, although buparvaquone did not eliminate the parasites infecting the CNS, the drug represents an interesting lead with the potential to eliminate, or at least diminish, fetal infection during pregnancy.

Control and therapeutic management of bovine tropical theileriosis in crossbred cattle

Bovine tropical theileriosis (BTT) is a disease of worldwide economic importance in cattle, caused by Theileria annulata, a protozoan parasite, and transmitted cyclically by ticks. The disease is one of the serious constraints to dairy industry in endemic areas like India, leading to fatal infections in exotic cattle and significant mortality in cross-bred cattle and zebu cattle. The present report demonstrates the clinical manifestation, haematological alteration and therapeutic management of theileriosis cases in a cross-bred cattle dairy farm at district Bijnor, Uttar Pradesh. Clinical examination of affected animals revealed high rectal temperature (104-106 °F), generalized enlargement of superficial lymph nodes, pallor mucous, apathy and watery blood. The affected animals were severely infested with Hyalomma anatolicum ticks. The blood smears examination after staining with Leishman stain revealed the presence of typical Theileria organisms. Buparvaquone along with symptomatic and supportive therapy could cure all the animals.

Spectrofluorimetric determination of buparvaquone in biological fluids, food samples and a pharmaceutical formulation by using terbium-deferasirox probe

A simple spectrofluorimetric method is described for the determination of buparvaquone (BPQ), based on its quenching effect on the fluorescence intensity of Tb(3+)-deferasirox (DFX) complex as a fluorescent probe. The excitation and emission wavelengths were 328 and 545nm, respectively. The optimum conditions for determination of BPQ were investigated considering the effects of various affecting parameters. The variations in fluorescence intensity of the system showed a good linear relationship with the concentration of BPQ in the range of 10-1500μgL(-1), its correlation coefficient was 0.999 with the detection and quantification limits of 1.1 and 3.4μgL(-1), respectively. Linearity, reproducibility, recovery, limits of detection and quantification made the method suitable for BPQ assay in biological fluids, meat, dairy products and BPQ parenteral solutions (vials). The method was applied to real samples of serum and milk of three cows receiving BPQ.