diclazuril and Toxoplasmosis--Animal

Triazines are relatively new antiprotozoal drugs that have successfully controlled coccidiosis and equine protozoal myeloencephalitis. These drugs have favorably treated other protozoal diseases such as neosporosis and toxoplasmosis. In this article, we discuss the pharmacological characteristics of five triazines, toltrazuril, ponazuril, clazuril, diclazuril, and nitromezuril which are used in veterinary medicine to control protozoal diseases which include coccidiosis, equine protozoal myeloencephalitis, neosporosis, and toxoplasmosis.

Topics: Acetonitriles; Animals; Antiprotozoal Agents; Coccidiosis; Encephalomyelitis, Equine; Horses; Nitriles; Protozoan Infections, Animal; Toxoplasmosis, Animal; Triazines

Toxoplasma gondii is a widespread zoonotic protozoan that infects most species of mammals and birds, including poultry. This study aimed to investigate the course of T. gondii infection and the efficacy of diclazuril and Artemisia annua in preventing infection in experimentally infected chickens. Seventy-five 1-month-old chickens, female and male, were randomly divided into five groups (n = 15 each) as follows: (1) uninfected untreated (negative control, NC); (2) infected with T. gondii genotype II/III isolated from a wild cat (group WC); (3) infected with T. gondii genotype II isolated from a domestic cat (group DC); (4) infected with T. gondii domestic cat strain and treated with the anticoccidial diclazuril (group DC-D); and (5) infected with T. gondii domestic cat strain and treated with the medicinal plant Artemisia annua (group DC-A). Clinical signs, body temperature, mortality rate, weight gain, feed conversion ratio, hematological parameters, and the presence of T. gondii-specific IgY antibodies were recorded in all groups. Five chickens per group were euthanized 28 days post-infection (p.i.) and their brains, hearts, and breast muscle tested for T. gondii by mouse bioassay and polymerase chain reaction (PCR). No clinical signs related to the experimental infection were observed throughout the study period. T. gondii-specific antibodies were detected by day 28 p.i., but not in all infected chickens. Overall, T. gondii DNA was detected (bioassay or tissue digests) in all infected and untreated chickens (10/10), while viable parasite (bioassay) was isolated from 7 out of 10 chickens. The parasite was most frequently identified in the brain (7/10). There were no differences in the T. gondii strains regarding clinical infection and the rate of T. gondii detection in tissues. However, higher antibody titers were obtained in chickens infected with T. gondii WC strain (1:192) comparing with T. gondii DC strain (1:48). A. annua reduced replication of the parasite in 3 out of 5 chickens, while diclazuril did not. In conclusion, broiler chickens were resistant to clinical toxoplasmosis, irrespective of the strain (domestic or wild cat strain). The herb A. annua presented prophylactic efficacy by reduced parasite replication. However, further studies are required aiming at the efficacy of diclazuril and A. annua for the prevention of T. gondii infection in chickens using quantitative analysis methods.

Topics: Animals; Antibodies, Protozoan; Artemisia annua; Brain; Cats; Chickens; Coccidiostats; Female; Genotype; Heart; Male; Mice; Nitriles; Pectoralis Muscles; Plants, Medicinal; Poultry Diseases; Random Allocation; Seroconversion; Tissue Distribution; Toxoplasma; Toxoplasmosis, Animal; Triazines

The 'Alala (Corvus hawaiiensis) is the most endangered corvid in the world, and intensive efforts are being made to reintroduce it to its former native range in Hawaii. We diagnosed Toxoplasma gondii infection in five free-ranging 'Alala. One 'Alala, recaptured from the wild because it was underweight and depressed, was treated with diclazuril (10 mg/kg) orally for 10 days. Antibodies were measured before and after treatment by the modified agglutination test (MAT) using whole T. gondii tachyzoites fixed in formalin and mercaptoethanol. The MAT titer decreased four-fold from an initial titer of 1:1,600 with remarkable improvement in physical condition. Lesions of toxoplasmosis also were seen in two partially scavenged carcasses and in a third fresh intact carcass. Toxoplasma gondii was confirmed immunohistochemically by using anti-T. gondii specific serum. The organism was also cultured by bioassay in mice from tissues of one of these birds and the brain of a fifth 'Alala that did not exhibit lesions. The life cycle of the parasite was experimentally completed in cats. This is the first record of toxoplasmosis in 'Alala, and the parasite appears to pose a significant threat and management challenge to reintroduction programs for 'Alala in Hawaii.

Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Biological Assay; Bird Diseases; Brain; Coccidiostats; Female; Hawaii; Immunohistochemistry; Liver; Male; Mice; Nitriles; Songbirds; Toxoplasma; Toxoplasmosis, Animal; Triazines

Diclazuril is a benzeneacetonitrile anticoccidial that is also effective in the prevention of toxoplasmosis. The present study was conducted to examine the efficacy of diclazuril alone or in combination with pyrimethamine for the treatment of acute toxoplasmosis in mice. Diclazuril administered at 10 mg/kg beginning 6 days after inoculation and given for 10 days protected 90% of mice over a 56-day observation period. Treatment with diclazuril at 1.0 or 0.5 mg/kg protected 20 and 0% of mice, respectively. Treatment with pyrimethamine at 12.5 or 6.0 mg/kg protected 60 and 0% of mice, respectively. When diclazuril (1.0 or 0.5 mg/kg) was combined with pyrimethamine (12.5 mg/kg) all mice survived the 56-day observation period. When diclazuril (1.0 or 0.5 mg/kg) was combined with pyrimethamine (6.0 mg/kg) 30 and 10% of mice, respectively, survived the 56-day observation period.

Topics: Acute Disease; Animals; Coccidiostats; Drug Therapy, Combination; Female; Mice; Nitriles; Pyrimethamine; Toxoplasmosis, Animal; Triazines

The capability of diclazuril, a benzeneacetonitrile anticoccidial agent, to inhibit development of tachyzoites of Toxoplasma gondii was examined in cultured human foreskin fibroblast cells and in Hsd:ICR mice. Treatment of infected cell cultures with 10.0, 1.0, 0.1 or 0.01 microgram of diclazuril/ml for 3 days resulted in > 99% reduction in tachyzoite counts, compared with controls. Treatment with 0.005 microgram of diclazuril/ml resulted in > 97% reduction in tachyzoite counts, compared with controls. Treatment of host cells with 10.0, 1.0, 0.1 and 0.01 microgram of diclazuril/ml for 24 hours prior to tachyzoite inoculation resulted in 97, 31, 0, and 0% reduction in tachyzoite counts, compared with controls, respectively, 3 days after inoculation. All mice that were treated orally with 10.0 mg of diclazuril/kg of body weight and 80% of mice treated orally with 1.0 mg of diclazuril/kg 1 day prior to and for 10 days after tachyzoite inoculation were protected against acute toxoplasmosis. Mice treated with 10.0 mg of diclazuril/kg did not develop protective immunity, whereas mice treated with 1.0 mg of diclazuril/kg survived challenge exposure.

Topics: Animals; Cells, Cultured; Female; Fibroblasts; Humans; Mice; Mice, Inbred ICR; Nitriles; Toxoplasma; Toxoplasmosis, Animal; Triazines