Summary data of mean change in body weight of experimental and control mice for. Comparative data of the number of seropositive mice exposed to different doses of brain tissue homogenate (BTH+) that showed histopathological abnormalities in the.
INTRODUCTION
Collection and Identification of Rats
The rats captured were individually caged at the De La Salle University-Dasmariñas (DLSU-D) Laboratory Research Facility. The physical characteristics and morphometrics of the rat species used in the present study were recorded (Table 1), and the rats were identified as R.
The displayed characteristics and morphometrics were consistent with those reported earlier by Sumangil (1990), Fernando et al. Sera that had anti-T.gondii Abs titers of ≥ 1:64 were further tested to distinguish between acute (phase of infection characterized by proliferation of tachyzoites) and chronic (phase of infection characterized by tissue cyst formation) infections.
This was done by washing the cages daily and removing and cleaning the removable board at the bottom to wash away food waste, urine and faeces. Cages (320 x 150 x 150 cm) were large enough to allow rats to perform normal behaviors such as exploration and grooming.
Preparation of Brain Tissue Homogenate
Using a pipette, the sera were transferred into correctly labeled test tubes, stored in a refrigerator (4–8 °C) and serologically processed within 24 hours after collection. The test kit contains a suspension of polystyrene latex particles of the same size coated with soluble Toxoplasma gondii Ags.
Monitoring of progression and infection in mice exposed to BTH + (Figure 3)
The body weights of experimental and control mice in gm were recorded before inoculation, then at seven days PE and weekly thereafter until sacrifice. Normal histological conditions for the control mice were noted using several references (Young and Heath, 2000; Burkitt et al., 1996; di Fiore, 1989; Cormack, 1987) and these were compared with the experimental mice.
Termination of the experiment
Data Analysis
- Serologic data on experimental mice
- Examination of blood smear and intraperitoneal exudates of mice for T. gondii parasites
- Monitored change in body weight of experimental mice
- Mortality
- Histopathology of selected organs of seropositive (sero + ) mice
Summary data of the number of seropositive rats inoculated with brain tissue homogenates (BTH+) from Rattus species collected from agricultural (AGR), commercial (COM) and residential (RES) sites. Regardless of the source of BTH+, seropositivity was higher in mice exposed to the 1.0 ml inoculation dose. Summary data of mean change in body weight of experimental and control mice for four weeks after exposure (PE).
Comparison of mean weight change during four weeks of follow-up of sero+ mice inoculated with three different doses of brain tissue homogenate (BTH+) R. Tissue sections of lung, liver, spleen, heart, diaphragm and brain of 93 sero+ mice inoculated with R.n.-BTH+ and R.r.m.- BTH+ captured at AGR, COM and RES sites were evaluated/assessed the extent of tissue damage. Regardless of the BTH+ source, inflammatory cell infiltration was consistently seen in the lungs, liver, diaphragm,
Comparative data on the number of seropositive (sero+) mice exposed to different doses of brain tissue homogenate (BTH+) that showed histopathological abnormalities in different organs.
Lungs
Parasites were detected in blood vessels showing congestion and pneumonic interstitial lung tissue (Plates 13A & B). Interestingly, the severity of injury was more pronounced in the bronchioles of R.n.-BTH+ infected mice. The histopathological changes noted in WK-4 PE mice, interstitial pneumonia and vascular vasculitis, atelectasis and pulmonary congestion observed in the present study are pathological changes that have been previously reported in birds (Dubey et al., 2001) and in rats (Decker-Schluter et al., 1998; . Guimaraes et al., 1990; Shadduck, 1978).
Histopathogenesis leading to pulmonary congestion and pulmonary edema is the result of pulmonary vessel congestion and fluid transudation in the alveolar spaces (Burkitt et al., 1996). With increasing severity of parasite invasion, atelactase or collapse of the alveoli may develop (Sandritter and Thomas, 1979) and emphysema, which is characterized by a large empty space bordered by thin, ruptured alveolar septa with confluent alveoli (Burkitt et al. , 1996). ).
Liver
The thickening of the alveolar septum has been attributed to the migration of inflammatory cells along the alveolar septa, coupled with bleeding (Burkitt et al., 1996; Sandritter and Thomas, 1979), and the accumulation of lymphocytes, plasma cells or histiocytes in the alveolar walls in presence of the parasites. The liver is one of the preferred target organs of proliferative tachyzoites causing multiple infectious lesions, reflecting the. Acute inflammation of the liver parenchyma characterized by focal accumulations of inflammatory cells at necrotic sites (Tseng, 1986; Burkitt et al., 1996) in T.
Follicular hyperplasia, which is a form of acute inflammatory response involving the giant macrophages, and necrosis of the white pulp were manifestations in all sero+ mice exposed to 0.75-1.0 ml BTH at WK-3 PE (plates 19C- D). In three out of four dead mice exposed to 1.0 ml R.n.-BTH+, white pulp hypoplasia (=incomplete or arrested development) was observed (Plate19F).
Heart
The spleen is a secondary lymphoid organ with a large concentration of lymphocytes, T and B cells, and macrophages. The presence of parasites and the host's immune response can cause follicular hypoplasia, and in cases of severe infection, the white pulp is depleted of immune cells, with replacement cells taking longer to replace them (Stites et al. , 1984). Necrosis, is a cell-mediated immune reaction resulting in loss of striae crissica and myocardium (= inflammatory myocardial damage), a histopathology showing T.
At WK-3 PE, tissue cysts were found in the heart muscle of only R.r.m.-BTH+/RES mice, indicating the avirulent or. Tissue cysts are not necessarily harmful to the host, as they are considered a protective mechanism to spare the parasites from immunological attacks, giving them greater chances of survival (Roberts and McLeod, 1999; Guimaraes et al., 1990; Dubey and Frenkel, 1972).
Diaphragm
Furthermore, Folkers (1974) and Frenkel (1973) noted the presence of parasites in the spleen and other lymphoid organs for two weeks, in the liver and lungs for 10 weeks. Once immunity develops, they find their way into the muscles and brain, where they form tissue cysts and can remain there for two years PE.
Brain
Intracellular parasites in tachyzoites and tissue cysts were detected in the brains of R.r.m.-BTH+-exposed mice at WK-4 PE (plates 28A & B). Tissue cysts were observed in the brain of R.r.m.-BTH+/RES at WK-4 PE, suggesting chronic phase of infection. The detection of brain tissue cysts in R.r.m.-BTH/RES at WK-4 PE in the present study is in contrast to the results of Feldman (1994) and Dubey and Beattie (1988), where tissue cysts were detected as early as 1-3 WK PE.
Considering the presence of tissue cysts in the heart muscle and diaphragm as early as WK-3 PE and less severe histopathology in the organs of mice exposed to R.r.m.-BTH+, T. tissue cysts were found in the heart, diaphragm and brain as early as WK-3 PE in sero+ of mice vaccinated with R.r.m.-BTH+/RES.
Conclusions
Histopathological conditions such as infiltration of inflammatory cells, vasculitis, and congestion and dilation of blood vessels were consistently seen in the examined organs. Even in WK-1 PE, histopathological manifestations were observed in the lungs, liver, spleen, heart, diaphragm, and brain, especially pronounced in the lungs and liver. As infection progressed in WK-4 PE, tissue damage became more evident in the spleen, heart, diaphragm, and brain.
Histopathologic manifestations consisted of interstitial pneumonia, alveoli atelactase, and pulmonary congestion due to haemorrhage. The detection of tissue cysts in the diaphragm, heart and brain of mice already exposed to R.r.m.-BTH+/RES during WK-3 PE is indicative of the avirulence/low virulence of T.
Recommendations
Structures of Toxoplasma gondii tachyzoites, bradyzoites and sporozoites and the biology and development of tissue cysts. Prevalence of antibodies against Toxoplasma gondii in sera of domestic pigs and some game species from Zimbabwe. Detection of Toxoplasma antigens and antibodies in mice infected with different Toxoplasma gondii strains.
A study of the presence of Toxoplasma gondii antibodies in cats raised in the Philippines using the enzyme-linked immunosorbent test. Detection of Toxoplasma gondii tachyzoites and bradyzoites in blood, urine and brain of infected mice.
Qualitative test
The reactants were mixed by gently tapping the side of the plate for 30 seconds and then the plate was placed in a shaker for 30 seconds. The reading of the results was based on the reaction of the specific Abs present in the serum of rats infected with Toxoplasma gondii with the Ags reagent. Therefore, a reaction showing a smooth cell mat covering all or nearly all of the bottom of the well (agglutination) appears to be a positive reaction.
Test can be performed again after 2-3 weeks to observe the possible evolution of the abs titer. This is interpreted as presence of Abs and a quantitative test will be performed to find the titer of Abs.
Quantitative test
The reagent vial was shaken to obtain complete homogenization, so no sediment should be observed at the bottom of the vial. Alternatively, the reaction components were mixed by gently tapping the side of the plate for 30 seconds. The reading of the results was based on the reaction of specific Abs present in the serum of mice infected with Toxoplasma gondii with the Ags reagent.
Therefore, a reaction showing a smooth mat of cells covering all or almost all of the bottom of the well (agglutination) was considered a positive reaction. If there is no reaction, the highly purified suspension of Toxoplasma settled from Ags reagent and formed a clear bottom, therefore no agglutination occurred.
Test for the Differentiation of IgG-IgM c.1 Preparation of serum
- Tissue Preparation
- Tissue Processing ( Bruce-Gregorios, 1974 with slight modification)
The Toxocell latex agglutination test (LAT) is a qualitative test for anti-T.gondii Abs, and is used to determine the presence or absence of the parasite in the experimental mice. The tissues (lungs, liver, spleen, heart, diaphragm and brain) were washed and cleaned after being detached from the mice's body. The paraffin blocks containing the specimen were fixed on the block holder of the microtome for sectioning (the correct orientation of the specimen desired for sectioning was noted).
This is checked by looking at a section of tissue under a microscope to see if the nuclear structures have taken up the stain. This was verified by looking at a tissue section under a microscope to see if the cytoplasmic structures had taken up the stain.
APPENDIX I
This is also characterized by alveolar consolidation or the combination of alveolar walls causing the loss of the alveolar sac. Alveolar lining thickening due to hemorrhage and infiltration of mononuclear inflammatory cells. Untidy coat as a result of the animal's failure to clean its body regularly; due to the lack of the habit of cleaning which is a manifestation of the weakness of the body.
The coat is wrinkled and agitated, usually seen on the back of the body, just below the head. The occasional habit of scratching the surface of the skin as a sign of discomfort and pain.
