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To examine the susceptibility of pigs for elaphostrongylosis, six 3.5-month-old Vietnam pigs were infected with doses of from 500 to 10000 invasive larvae of E. cervi. In all infected pigs any clinical symptoms of infection were observed. After one month post infection a necropsy of the pig infected with 5000 larvae was conducted. On the surface of the liver itself were found 6 white nodules from 2 to 6 mm in diameter. Third stage larvae of E. cervi were found in enlarged mesenteric lymph nodes. Most of them were dead, but after isolation some were still alive. The rest of the pigs infected with doses of 3000, 2000, 1000, 500 and 10000 larvae, were necropsied successively after 2, 3, 4, 5 and 6 months post infection. Any pathological changes were observed in their organs. In the pig necropsied 2 months post infection, dead E. cervi larvae or their fragments were found in mesenteric lymph nodes, and in the rest of the pigs, in this same localization, only fragments of dead larvae or detritus after their resorption were found. Histopathological examinations confirmed the presence of parasitic nodules in lymph nodes and in livers in which cross-sections of larvae of this parasite have been seen. Results of the presented investigations indicate that pigs are not susceptible to infection of E. cervi larvae. One can suppose that a similar low susceptibility to the discussed parasitosis occur in other omnivorous animals and also in men.
The development and prevalence of gastro-intestinal larvae of sheep in the Lublin region have been studied for 3 years. Feces of sheep containing numerous eggs of trichostrongyloides were laid out on grass plots from April until December. Every three days the grass was cut and examined by Baerman’s method for the presence of larvae. Results of the experiment revealed that the development of larvae in spring was extended to 9 weeks. In summer (July and August), when temperatures did not show day and night fluctuations, the period of larvae development was reduced to 3 weeks. Prevalence of larvae on grass was 35 days in spring and 30 days in summer.
The activation of muscle cell nucleus in the course of T. spiralis infection, established using morphological methods (part I), has been confirmed in histochemical (histones, RNP) and histoenzymatic (RN-aze) investigations. The activity of the cell nucleus increased from the 5th day after infection up to the complete encapsulation of the larva (30th day) however it remained at a weak stable level in later stages of infection.
The objective of the study was to establish possibilities of the development of the I stage larvae of E. cervi in fishes and amphibians, and possibilities of paratheny in the organism of these animals. In the alimentary tract of the fishes both the I stage and the invasive (i.e. III stage) larvae can not cross the intestine barrier and undergo digestion. However, in the frag organism the I stage larvae of E. cervi are capable of crossing the wall of the alimentary canal and of going through a part of their development, though not attaining the II stage. The invasive larvae fed to the frogs penetrate under the peritoneum, into the mesenterium and the muscles and there they survive inside cysts. Frogs as parathenic hosts for E. cervi can be dangerous for predators feeding on amphibians. The larvae of E. cervi liberated in their organism can pass through the cerebral phase of their development thus causing neural clinical symptoms.
Single doses (from 300 to 1000 larvi per an animal) of invasive larvae E. cervi Cameron, 1931, obtained from experimentally infected snails Helix pomatia L. were given to 17 guinea pigs and 17 golden hamsters. Clinical nervous symptoms in the form of paresis and paralysis of limbs occurred only in the guinea pigs which were given a dose of 1000 larvi. These animals died in the period from the 75th to 117th day of infection. From their central nervous system single adult males and females of E. cervi were isolated. In the lungs and mesenteries of 2 dead pigs live larvae of E. cervi were found. This fact proves that the guinea pig can fulfil the role of a final and a paratenic host of E. cervi. No clinical symptoms were noticed in any hamster. In hamsters dissected on the 7th day of infection live larvae of E. cervi were found in the mesentery and in the fleshy part of the diaphgram. After 14 days the larvae found both in the mesentery and in the diaphragm were dead and surrounded by cellular infiltration. A strong tissue reaction of the hamster after the administration of E. cervi larvae is responsible for the larvae destruction and resorption.
The guinea pigs were administrated vit. A (400 i.u.), vit. B₂ (1 mg) or vit. B₁₅ (5 mg). On the 9-th day of the experiment part of them was infectpd with 5000 invasive eggs of Ascaris suum. The invasion lasted 6 days and was controlled by lungs and kidney weight, and number of larvae in the lungs. The activity of amylase was determined by saccharogenic method in both organs. In the lungs of infected animals the activity of alpha-amylase was abouth 3 times lower than in the control. The infection of guinea pigs which were given vitamins did not cause change of enzyme's activity. In the kidney directive tendency was the same, but the differences were smaller. The infection resulted in an increase of relative mass of lungs. This index and number of larvae was considerable smaller in guinea pigs with vitamins A and B₁₅ administration. Any testing agent did not cause change of relative weight of kidney.
The studies were carried out on 40 guinea pig males weighting about 230 g. The experimental animals were infected with 7000 invasive eggs of Ascaris suum. On the 3-rd, 7-th and 10-th day after infection the activity of alpha-amylase was estimated according to Caraway's method in serum, liver, pancreas, lungs, kidneys and spleen. The infection of guinea pigs results in increased activity of enzyme in serum and spleen, and decreased in pancreas, liver, kidneys and lungs. On the 3-rd day after infection the changes in amylase activity were the most intense.
The percentage of NBT-positive cells in peritoneal fluid, spleen and mesenteric lymph node of CWF mice infected orally with 200 Trichinella spiralis larvae was investigated. The highest level of NBT-positive cells in peritoneal fluid was found on the 5-6th and 50-60th day post infection (p.i.), in spleen between the 30-75th and in mesenteric lymph node between the 50-75th day p.i. The lack of reaction between peritoneal fluid cells and newborn migrating larvae at the 15th and 20th day p.i. observed by the authors, may be associated with slight activity of these cells in the NBT reduction test between 8-30th day p.i.
The infection of guinea pigs with Ascaris suum larvae resulted in decrease of the activities of trypsin and alpha-amylase, and in increase of lipase activity in extracts from their pancreas. The activity of alpha-amylase, lipase and the relative weight of lungs of infected animals which were given vitamin A, did not differ from control animals. The activity of trypsin from pancreas these animals was higher than that measured in only infected guinea pigs but it was lower than in control animals. Application of vitamin B₂ and the infection of guinea pigs with A. suum did not lead to the synonymous results.
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