RU2480215C1 - Method of treating feline calicivirus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to veterinary science. The method comprises the oral administration of Ribavirin-Lipint 20-25 mg/kg of body weight once a day, before feed intake, for 10 days.

EFFECT: method provides a high therapeutic effect, reduces the length of animal's recovery.

3 tbl, 3 ex

Description

The invention relates to veterinary medicine, and in particular to methods of treating feline calicivirosis.

A known method of treating feline calicivirosis, including the use of the antiviral drug ribavirin (Povey RC Effect of orally administered ribavirin on experimental feline calicivirus infection in cats / RCPovey // Am. J. Vet. Res. - 1978. - Vol. 39. - P. 1337-1341). A method of treating feline calicivirosis involves the oral administration of ribavirin at a dose of 75 mg / kg of animal weight, in 3 doses per day, for 10 days.

Ribavirin is an antiviral drug, a synthetic analog of nucleosides, the mechanism of action of which is to inhibit adenosine monophosphate dehydrogenase, which leads to inhibition of the synthesis of viral RNA and DNA. At the same time, ribavirin selectively inhibits the synthesis of viral RNA without inhibiting the synthesis of RNA in normally functioning cells. Ribavirin easily penetrates into the affected cells and is rapidly phosphorylated by intracellular adenosine kinase to ribavirin mono-, di- and triphosphate. These metabolites, especially ribavirin triphosphate, have a pronounced antiviral activity. Ribavirin inhibits the replication of new virions, which reduces the viral load. It has been established that ribavirin preparations are effective against many DNA and RNA viruses that are not sensitive to other antiviral drugs, including the feline calicivirosis virus.

However, studies on the antiviral activity of ribavirin in relation to feline calicivirosis were carried out on a small number of experimentally infected animals, which does not provide reliable data on the dose and timing of its use, contributing to the recovery of cats naturally infected with this virus. The dose in the proposed method is quite high, causes toxicosis, accompanied by a decrease in the number of red blood cells and white blood cells, an increase in the activity of alanine aminotransferases (ALT), the appearance of jaundice, weight loss.

Despite the high activity of ribavirin against many viruses, the drug was not used in veterinary practice due to severe toxicity.

The most acceptable, from the point of view of the described shortcomings, and adopted for the prototype is a method of treating human hepatitis C using the drug ribavirin-Lipint.

Ribavirin-Lipint is a new preparation of liposomal ribavirin, using the mechanism of targeted delivery of the substance. Ribavirin-Lipint has less toxicity and higher therapeutic efficacy than existing ribavirin preparations.

This drug has been clinically tested and recommended for the treatment of hepatitis C in humans. The dose of ribavirin-Lipint in this method of treatment is 1000 mg per day (1 bottle in the morning and 1 bottle in the evening).

There are no data on the use of the drug ribavirin-Lipint in calicivirusosis.

The objective is to expand the arsenal of methods for treating feline calicivirosis.

The stated technical problem is solved in that in the known method of treating calicivirosis in cats, including oral administration of ribavirin-Lipint, according to the invention, cats are fed ribavirin-Lipint in a dose of 20-25 mg / kg body weight 1 time per day, before feeding, for 10 days.

The invention is illustrated by the following examples.

Example 1

Determination of the antiviral activity of the drug ribavirin-Lipint in relation to the cat calicivirosis virus in vitro

In the experiments, the cat calicivirosis virus (strain Lars-30DEP) was used. Infectious activity of the virus was determined in a sensitive transplanted line of cultures of the cells of the kidney of a kitten (F-81). The cultivation and infection of the cells with the feline calicivirus virus was carried out on the transplanted cell culture line F-81 (kitten's kidney) in cell culture vials (Nunc, Denmark) until a 100% cytopathogenic effect appeared. Cells were grown in MEM’s Needle medium with a double set of amino acids and vitamins (manufactured by the Federal State Unitary Enterprise “The Production of Bacterial and Viral Preparations Research Institute of Poliomyelitis and Virus Encephalitis named after MP Chumakov RAMS”) with the addition of 5-10% fetal calf serum (HyClone , lot No. ASA28574), 0.06% L-glutamine and 100 μg / ml kanamycin. Cells were cultured at 37 ° C and 5% CO ₂ . As the supporting medium used the same medium without serum.

Determination of toxicity and antiviral activity of the drug was carried out in accordance with the "Guidelines for the experimental (preclinical) study of new pharmacological substances" (R.U. Khabriev, Publishing House Medicine, 2005. - 832 p.).

The infectious activity of feline calicivirosis virus was determined by micromethod in 96-well culture plates (Costar) with F-81 cell culture using at least four parallel rows. The infectious titer of the virus was expressed in T _{CD50 / 0.1 ml} (50% tissue cytopathic dose).

Determination of antiviral activity of the drug in vitro. The monolayer of the used cell culture was infected with cat calicivirosis virus at a dose of at least 1 TCD / cell, 1.5 hours later it was washed with serum-free culture medium and the drug was added in a 50% inhibitory dose (experiment) or dilution medium (control). After 72 hours of culturing the virus in such a biosystem, the culture fluid was titrated. The antiviral effect of the drug was calculated by the ratios of the infectious activities of the virus in the experimental and control samples. In each experiment, an additional control was performed on the toxicity of the test dose of the drug (Table 1).

Table 1 Drug name The used dose of the drug The concentration of feline calicivirosis virus (M ± m), log TCD _{50 / 0.1 ml} Experience The control Ribavirin-Lipint 50 mcg / ml 3.17 ± 0.14 7.5 ± 0.24

As a result of the studies, it was found that the studied drug has an antiviral effect on the cat calicivirosis virus. The decrease in the infectious activity of the virus was 4.33 lg TCD _{50 / 0.1 ml.}

Example 2

Determination of the effective dose of the drug ribavirin-Lipint for the treatment of feline calicivirus.

To determine the effective dose of the drug ribavirin-Lipint in the focus of calicivirosis, experimental (3) groups of cats were formed according to the principle of analogues of 6 animals each. They noted: an increase in body temperature from 39.5 to 41.5 ° C, sneezing, coughing, serous-catarrhal outflows from the eyes and nose, refusal to eat, the presence of erosion on the nasal mucosa, oral cavity and tongue. In all animals, an acute respiratory form of calicivirosis due to the presence of the virus (Feline calicivirus virus) FCV was established clinically and according to the results of virological studies.

We used the commercial drug ribavirin-Lipint developed by the State Research Center of the World Bank “Vector”. The drug was drunk to animals before feeding in appropriate doses: the 1st group - 20-25 mg / kg, the 2nd - 30-35 and the 3rd - 40-45 mg / kg of the animal’s body weight, once a day for 10 days.

The animals were followed by clinical observations, biochemical blood tests, daily sampling of biomaterial for virological studies.

Clinical symptoms of calicivirosis were recorded daily before treatment and were monitored throughout the observation period.

The criterion for the effectiveness of therapy was the duration of the manifestation of clinical signs and the timing of detection of the virus in the nasal, conjunctival secretions and secretions from the oral mucosa. One of the main indicators of clinical recovery was a decrease in body temperature, restoration of appetite, the absence of outflows from the nose and eyes, coughing and sneezing, and erosion in the oral cavity. Virological recovery was determined based on the results of virological studies of samples of biomaterial taken from animals.

The results of studying the therapeutic efficacy of ribavirin-Lipint are presented in table 2.

In experimental group 1 in animals, the duration of clinical signs was 7–9 (7.83 ± 0.78) days, and the time for virus detection in biomaterial samples was 5–8 (6.83 ± 0.39) days.

The optimal treatment results for feline calicivirosis were obtained using ribavirin-Lipint at a dose of 20-25 mg / kg (experimental group 1).

table 2 Group of animals
(n = 6) Dose (mg / kg body weight) The duration of the manifestation of clinical signs, days (M ± m) Duration of virus detection in biomaterial samples, days (M ± m) Experienced 1 20-25 7.83 ± 0.78 6.83 ± 0.39 Experienced 2 30-35 7.67 ± 0.81 6.67 ± 0.45 Experienced 3 40-45 9.33 ± 0.81 6.33 ± 0.38

An increase in the dose of the drug to 30-35 mg / kg and 40-45 mg / kg did not lead to significant reductions in the duration of clinical signs in animals and the time for virus detection in samples of biomaterial in animals of experimental groups 2 and 3 in comparison with animals of experimental group 1.

Valuable information on the functional state of the liver is provided by the determination in blood serum of the activity of enzymes of hepatic origin - transaminases and alkaline phosphatase. Transaminases - alanine aminotransferase (Alt) and aspartate aminotransferase (AcT) are enzymes that catalyze the transfer of an amino group from amino acids to keto acids. The exit of transferases from hepatocytes and an increase in their activity in the blood is a marker of the initial stages of the cytolytic syndrome. An increase in the activity of alkaline phosphatase (ALP) in the blood serum indicates cholestasis syndrome with lesions of the hepatobiliary system.

The results of a study of the effect of ribavirin-Lipint on the activity of serum enzymes in experimental animals are presented in Table 3.

Monitoring the dynamics of changes in the biochemical parameters of the functional state of the liver allowed us to conclude that at the selected dosage (20-25 mg / kg), ribavirin-Lipint does not have a toxic effect on the hepatobiliary system of animals (Table 3), and gives optimal treatment results for feline calicivirus.

Table 3 Indicators 10 days after the use of the drug ribavirin-Lipint Before using the drug ribavirin-Lipint 20-25 mg / kg 30-35 mg / kg 40-45 mg / kg (n = 6) (n = 6) (n = 6) (n = 6) Alt, Unit / L 40.2 ± 0.6 50.9 ± 2.1 63.8 ± 0.9 39.1 ± 0.3 AST, Unit / L 41.2 ± 0.3 55.0 ± 0.5 63.6 ± 0.8 40.9 ± 0.7 Alkaline phosphatase, units / l 108.8 ± 0.9 115.9 ± 1.2 122.3 ± 1.1 109.6 ± 0.8

An increase in the dose of the drug to 30-35 mg / kg and 40-45 mg / kg was accompanied by an increase in Alt, AcT and alkaline phosphatase.

Example 3

To confirm the optimal treatment time for calicivirosis in cats with ribavirin-Lipint at a dose of 20-25 mg / kg, a production experiment was conducted on 32 cats. The results are presented in table 4.

The results of virological studies were negative in 84.4% of animals on the 5th day of treatment. The effectiveness of treatment by the 14th day was 100%.

Table 4 Treatment Efficiency Criteria Duration of observation, days 5 7 fourteen The number of animals without clinical manifestations 28 thirty 32 signs of calicivirus, goals % of the total number of animals 87.5 93.75 one hundred The number of animals with negative results of virological studies of nasal secretions 27 29th 32 % of the total number of animals 84,4 90.6 one hundred

Thus, the proposed method for the treatment of feline calicivirosis significantly reduces the recovery time of animals and allows you to use the optimal dose of the drug, which does not worsen the general condition of the body and has promise in the treatment of feline calicivirosis.

Claims (1)

A method of treating feline calicivirosis, including oral administration of ribavirin-Lipint, characterized in that the drug is used in a dose of 20-25 mg / kg body weight 1 time per day before taking the feed for 10 days.