Infection with the intracellular protozoan parasite Toxoplasma gondii causes serious public health problems and is of great economic importance worldwide. The micronemal protein MIC3, which is a potent adhesin of T. gondii, could be a significant candidate vaccine against toxoplasmosis. In this study, all CBA/J mice intramuscularly vaccinated with a plasmid encoding the immature form of the MIC3 protein (pMIC3i) produced specific anti-MIC3 immunoglobulin G (IgG) antibodies, and their sera displayed high antibody titers. This response was increased by the coadministration of a plasmid encoding the granulocyte-macrophage colony-stimulating factor (pGM-CSF). Similarly, a specific and significant cellular immune response was obtained in mice immunized with pMIC3i, and this response was markedly enhanced by pGM-CSF coadministration. The cellular immune response was associated with the production of gamma interferon IFN-␥ and interleukin-2 (IL-2), indicating that this was a Th1-type response. This was confirmed by the production of large amounts of IgG2a. Mice immunized with pMIC3i displayed significant protection against an oral challenge with T. gondii 76K cysts, exhibiting fewer brain cysts than did the control mice. Coadministration of pGM-CSF enhanced this protection. In conclusion, this study describes the design of a potent DNA vaccine encoding the novel T. gondii target antigen, MIC3 protein, that elicits a strong specific immune response as well as providing effective protection against T. gondii infection. In the attempt to achieve complete protection against toxoplasmosis, MIC3 is a good candidate vaccine which could be combined with other relevant and previously described candidates, such as SAG1 and GRA4.

Mic1-3KO is an effective vaccine against chronic and congenital toxoplasmosis.

This study assessed the effectiveness of a mutant strain of Toxoplasma gondii (RH strain) lacking the mic1 and mic3 genes (Mic1-3KO) against Toxoplasma abortion in sheep. Ewes were inoculated subcutaneously with 105 Mic1-3KO tachyzoïtes in three independent experiments. Following vaccination, Mic1-3KO induced a mild febrile response and serum IgG antibodies, which persisted throughout the experiments. Tissue cysts formed in the sheep, but were not, under our experimental conditions, infectious when given orally. Ewes were mated two months after vaccination and were orally challenged with the PRU strain of T. gondii at mid-gestation (400 oocysts in Experiments 1 and 2; 100 oocysts in Experiment 3). Challenge of vaccinated pregnant ewes resulted in a slight febrile response, whereas unvaccinated ewes developed a more severe, characteristic febrile response of longer duration. After challenge, all unvaccinated ewes aborted whereas 62%, 91% and 64% (Experiments 1, 2 and 3 respectively) of the lambs from vaccinated ewes were viable, with no clinical signs of infection. Mic1-3KO was as effective as S48, the strain used as a live vaccine for sheep (Toxovax®). A dose of 105 Mic1-3KO tachyzoites was sufficient to induce protection (versus a dose of 2 × 106). Both subcutaneous and intraperitoneal injections were effective. Moreover, preliminary results showed the potential of Mic1-3KO to reduce the development of tissue cysts in lambs born to vaccinated ewes. This study demonstrates that Mic1-3KO is a potent vaccine candidate.

Clinical, haematological, and biochemical changes induced by naturally occurring babesiosis in dromedary camels were described. Of 258 dromedary camels studied, 34 camels suffered from fever, appetite loss, weakness, depression, and reluctant movement; abortion and/or infertility were also observed. Parasitological blood examinations were performed using Giemsastained blood smears. The clinically affected animals were diagnosed with babesiosis, with 13.17% overall morbidity. Camels that suffered from babesiosis were subjected to haematological and biochemical analyses and the affected group was compared with a control group containing 34 healthy camels. The affected animals showed a highly significant (P<0.001) reduction of the total red blood cell (RBC) count, haemoglobin (HGB) concentration, and mean corpuscular volume (MCV) as well as a highly significant reduction (P<0.01) of haematocrit (HCT) and a significant reduction of (P<0.05) mean corpuscular haemoglobin (MCH). Additional, highly significant increases (P<0.01) in white blood cell (WBC) count and plateletcrit (PCT) percentage were detected. However, other haematological parameters were not significantly altered. There was a very significant reduction (P<0.001) of the blood iron level and a very significant increase (P<0.001) in blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) in the affected camels. Additionally, significant increases in total protein, albumin, γ-glutamyltransferase (GGT), aspartate aminotransferase (AST), and total bilirubin were observed in the affected camels. It was concluded that babesiosis highly affects the haematobiochemical parameters of dromedary camels, including the liver, kidney, and muscle functions. These results represent novel findings concerning natural babesiosis in camels.