Artemisone inhibits in vitro and in vivo propagation of Babesia bovis and B. bigemina parasites.

Artemisone was evaluated, in in vitro and in vivo, for control of bovine babesiosis caused by Babesia bigemina and Babesia bovis parasites. In vitro, artemisone reduced parasitemia in a dose-dependent manner: the inhibitory effects increased gradually, reaching a maximum inhibition of 99.6% and 86.4% for B. bigemina and B. bovis, respectively 72 h after initiation of treatment with initial parasitemia of 0.5%. In calves infected with either B. bigemina or B. bovis artemisone treatment was well tolerated and prevented development of acute babesiosis in all animals except for one B. bovis-infected calf. The treatment did not eliminate all blood parasites, and recovered animals carried a persistent low-level infection. Treatment with artemisone may be useful as an alternative drug for preventing the pathology that results from babesiosis, without interfering with acquired immune protection following recovery from an acute babesiosis infection or vaccination.

Neosporosis in naturally infected pregnant dairy cattle.

Neosporosis caused by caused by the apicomplexan parasite Neospora caninum is one of the major causes of infectious abortion in bovines worldwide. A long-term prospective study was performed in a dairy herd endemic for N. caninum in order to analyze the impact of neosporosis on the proportion of aborting cows. A total of 1078 pregnant cows were tested for presence of antibodies and the proportion of abortions was calculated. The overall seroprevalence of N. caninum found in the herd was 35.5%. The percentage of abortions in seropositive cows was 3 times higher than in their seronegative counterparts (21.6 and 7.3%, respectively). No statistically significant association was found between the antibody level of positive during pregnancy and the proportion of aborting cows. However, 41.2% of the dams with antibody titers of 1:12,800 aborted. The risk of abortion for such dams was 2.7 times higher than for other seropositive cows which had lower titers of antibodies (p=0.0072). In the follow-up examinations of the seropositive cows during several pregnancies, the overall percent of abortions observed was significantly higher than in seronegative individuals (49.3 and 16.9%, respectively; p<0.0001). Moreover, the proportion of repetitive abortion observed was 5 to 1 (17.4 and 3.5%) in seropositive and seronegative dams, respectively (p<0.001). The rate of vertical transmission in positive dams was 61.0% and it appeared to be directly associated with antibody levels: the higher the titer in the dams during pregnancy, the higher the percentage of sero-positivity in their calves. Increased proportion of abortions was observed in seropositive cows both in summer and winter in comparison with spring and autumn. It was found that in seropositive cows, an increased number of pregnancies, which was directly related to the age of the dam, has been associated with an increased number of abortions.

Neospora caninum: in vivo and in vitro treatment with artemisone.

Neosporosis caused by Neospora caninum has global economic, clinical, and epidemiological impacts, mainly in the cattle industry. Currently, there is no useful drug for treatment of neosporosis. This publication is the first to describe the significant benefits that artemisone has on Neospora infections both in vitro and in vivo. Artemisone is a new semi-synthetic 10-alkylamino artemisinin that is superior to other artemisinin derivatives in terms of its significantly higher antimalarial activity, its tolerance in vivo, lack of detectable neurotoxic potential, improved in vivo pharmacokinetics and metabolic stability. Low micromolar concentrations of artemisone inhibited in vitro Neospora development. Prophylactic and post-infection treatment profoundly reduced the number of infected cells and parasites per cell. In the in vivo gerbil model, a non-toxic dose prevented typical cerebral symptoms, in most animals. There were no signs of clinical symptoms and brain PCR was negative. Most treated gerbils produced high specific antibody titer and were protected against a challenge. Overall, artemisone could be considered as a future drug for neosporosis.