Microscopic changes in some organs of cats at the infectious peritonitis

Abstract

The study's relevance is that pathomorphological changes in the infectious peritonitis of cats have been studied by a few authors and still need to be fully described. This paper describes the microscopic changes in the brain and spinal cord, liver, and somatic and visceral lymph nodes in cats with infectious peritonitis. The leading research method is a histological examination of sections obtained from the listed organs of cats of various ages that died from mixed (26 animals) and dry (7 animals) forms of infectious peritonitis. Sections were stained with hematoxylin and eosin according to the generally accepted method. It was found that microscopic changes in the brain and spinal cord do not depend on the form and duration of the disease. Gray and white matter are swollen, blood vessels are spasmodic, and nerve cells are in basophilia. A particularly significant swelling was found in the white matter of the spinal cord, which at the same time underwent lysis. In the liver, microscopic changes do not depend on the disease's form but are somewhat different depending on the duration of its course. In cats that were ill for less than three weeks before death, fibrinous-necrotic overlays are found on the surface of the capsule in places. Areas where mesotheliocytes of the capsule undergo metaplasia, are also seen – they acquire a cubic or columnar shape. In some places, the liver capsule is destroyed. The portal tracts are swollen and infiltrated with a small number of lymphocytes and monocytes, and the walls of the arteries of the hepatic triad are necrotized. Foci of tissue necrosis of the portal tract are also detected. Veins and bile ducts are not differentiated. Liver lobules are infiltrated with lymphocytes and monocytes. Cell swelling and destruction of hepatocytes were established. In animals that were ill for more than three weeks before death, in addition to the changes typical for infectious peritonitis, portal hepatitis, edema, and disorganization of liver lobules, hydropic dystrophy, destruction, and necrosis of hepatocytes were found. Changes in the lymph nodes are individual and do not depend on the form and duration of the course of the disease. However, in all cases of the registry, there were foci of necrosis in the central part of lymphoid nodules and the paracortical zone.