Quantitative analysis of microfilarial periodicity of Dirofilaria immitis in cats.

Microfilarial periodicity of Dirofilaria immitis in the venous blood of infected cats was analyzed by a trigonometric model. Cats were infected by subcutaneous transplantation with 120-day-old juvenile D. immitis. Microfilariae in the blood were first observed 98 days after transplantation. Blood was collected at 4h intervals for a 24h period, and examinations were repeated five times in two cats. The calculated periodicity index was 75.1 and 50.3 in these two cats. The estimated hour of peak microfilarial density ranged from 1.00 to 2.84h. Thus, the periodicity of microfilariae of D. immitis in the blood of cats was characterized as nocturnally sub-periodic.

Influences of alkaline ionized water on milk electrolyte concentrations in maternal rats.

We previously reported that body weight on day 14 after birth in male offspring of rats given alkaline ionized water (AKW) was significantly heavier than that in offspring of rats given tap water (TPW), but no significant difference was noted in milk yield and in suckled milk volume between the two groups. Additionally, the offspring in the AKW group and TPW group were given AKW and TPW, respectively, at weaning, and unexpectedly, the necrotic foci in the cardiac muscle were observed at the 15-week-old age in the AKW group, but not in the TPW group. The present study was designed to clarify the factors which are involved in that unusual increase of body weight and occurrence of cardiac necrosis. Eight dams in each group were given AKW or TPW (control) from day 0 of gestation to day 14 of lactation. The milk samples were collected on day 14 of lactation and analyzed for concentrations of calcium (Ca), sodium (Na), potassium (K), magnesium (Mg) and chloride (Cl). The AKW and TPW were also analyzed. Ca, Na and K levels in milk were significantly higher in the AKW group compared to the TPW group. No significant difference was noted in the Mg and Cl levels between the two groups. These data suggested that the Ca cation of AKW enriched the Ca concentration of the milk and accelerated the postnatal growth of the offspring of rats given AKW.

Influences of alkaline ionized water on milk yield, body weight of offspring and perinatal dam in rats.

The authors previously reported that male offspring of mothers rats given alkaline ionized water (AKW) showed a significantly higher body weight by day 14 after birth than did offspring of mother rats given tap water (TPW); furthermore, marked myocardial necrosis and fibrosis were observed particularly in the former male offspring at the age of 15 weeks. In the present experiment we looked for differences in bioparameters, namely the milk yield of mothers and suckled milk volume of the offspring, between the AKW- and the TPW-treated groups in order to reveal the factors which cause the unusual body weight gain in the offspring. Even though we were able to repeat our previous observation (the body weight of the male offspring of the AKW group increased significantly more by day 14 and 20 after birth and of the female by day 20 after birth than did that of the TPW group (p < 0.05), no significant difference was noted in any of the bioparameters, including those related to milk production and consumption. It is thus suspected that the water-hydrated cation, which was transferred either to the fetus through the placenta or to the offspring through the milk, might be the cause of the unusual body weight increase. Since calcium plays an important role in skeletal formation, it is tentatively concluded that the higher calcium concentration of AKW enriched the mother, serum calcium which was transferred to the fetus through the placenta and to the offspring through the milk.

Histopathological influence of alkaline ionized water on myocardial muscle of mother rats.

We have reported that a marked necrosis and subsequent fibrosis of myocardium occurred among male rats 15 weeks old given alkaline ionized water (AKW) during gestation and suckling periods, and after weaning. In this study, it was examined whether similar lesions would occur in mother rats which were given AKW from day zero of gestation to day 20 of lactation. The myocardial lesion in the mother rats given AKW showed cell infiltration, vacuolation and fibrosis in the papillary muscle of the left ventricle, as were observed in male rats of 15 weeks old. Myocardial degeneration may cause a leakage of potassium into the blood that results in a higher concentration of potassium in the blood in the test group than in that of the control group given tap water.

[Detection of intestinal parasites from main-land raccoon dogs, Nyctereutes procyonoides viverrinus, in southeastern Kanagawa Prefecture].

To obtain the basic data on the route of infection of intestinal parasites as zoonosis, we examined the feces from 87 main-land raccoon dogs, all of which were kept in the Yokohama Kanazawa Zoo (Kanagawa) between 1994-1996, for detection of intestinal parasites and evaluated the detection rates. Intestinal parasites were detected from 72 of the 87 raccoon dogs (82.8%). Among the parasites, Ancylostoma spp., Trichuris vulpis, Ascaridoidea and Isospora spp. were most commonly detected. Of the 72 raccoon dogs with parasites, 43 (59.7%) had mixed infection of more than two species of parasites. Since Ancylostoma spp., Ascaridoidea and Isospora spp., which are important causes of human diseases, were detected at relatively high rates, it was suggested that the raccoon dog could be a source of human infection of intestinal parasites.

[Anti-toxoplasma antibody levels in the main-land raccoon dog, Nyctereutes procyonoides viverrinus, in southeastern Kanagawa prefecture].

Naturally-occurring toxoplasma infection has been observed for years in various kinds of wild animals. However, the infection situation has not been well characterized due to a lack of research. In present study, latex fixation tests were conducted for 109 main-land raccoon dogs (67 males and 42 females) all of which were kept in Kanazawa Zoo in Yokohama City, Kanagawa Prefecture between 1991-1994 to measure levels of toxoplasma antibodies. The test results indicated 20 positive samples out of the total 109, an 18.3% positive rate. This demonstrates that toxoplasma infection exists in the raccoon dog population in Kanagawa Prefecture, and that the raccoon dog could be a source of spread of toxoplasma infection. We believe there is significant reason to continue the investigation as a part of a prophylaxis for zoonotic diseases.

Swine erythrocyte fractionation in Percoll density gradients.

A method for the fractionation of swine erythrocytes according to age using Percoll is described. Centrifugation of erythrocytes on discontinuous Percoll gradients yielded four fractions of erythrocytes. To ascertain that each fraction of erythrocytes represented a different age group, the activities of hexokinase (Hx), aldolase, glyceraldehyde-3-phosphate dehydrogenase (GAPD), pyruvate kinase (PK), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were determined. These enzyme activities decreased successively from the top to the bottom fractions of the centrifuged column. Young erythrocytes obtained from the upper fractions of the centrifuged column exhibited a higher activity of each enzyme than that found in the heavier and older erythrocytes at the bottom fraction. This method is proposed as the most appropriate for use as an aid in distinguishing the presence of a young erythrocyte population.

[Studies on the giardiasis as the zoonosis. III. Prevalence of Giardia among the dogs and the owners in Japan].

To obtain the basic data on the route of Giardia infection as zoonosis, of many regions in Japan, the feces from 2218 dogs were examined for detection of Giardia cysts. Giardia cysts were detected in 239 of the 2218 dogs (10.9%), which was the same as previous reports from America. None were found from the owners of 51 dogs in which Giardia cysts were detected. The detection rates of each facilities were, 68 of 366 (18.6%) from the breeder's kennels, 169 of 1811 (9.3%) in individual houses, 2 of 42 (4.9%) from research institutes. The detection rate of the breeder's kennels was higher than the other two facilities (p less than 0.05, p less than 0.001). The detection rates of Kanagawa and Shizuoka prefectures among 17 regions in Japan were higher than the others (p less than 0.001, p less than 0.05). Especially in Shizuoka, the rate of the individual houses was higher than from breeder's kennels. In kanagawa the rates of the individual houses and the breeders kennels were higher than the mean in Japan (p less than 0.001). Therefore one must instruct the breeders when teaching health education to included zoonosis, and that the detection rate of the age groups of less than 3 years old was high-221 of 1276 (17.3%). Since the detection rates of Giardia cysts in the dogs were low, the possibility that human infection acquired from dogs was low. However, some of patients with giardiasis we encountered had never been abroad, and it is not yet clear whether Giardia is strictly host specific or not, so attention should be paid to the possibility of cross-infection between man and animals.

[Studies on the giardiasis as the zoonosis. II. Giardiasis in dogs and cats].

To obtain the basic data on the route of Giardia infection as zoonosis, we examined feces from 354 dogs and 34 cats for Giardia cysts and trophozoites and evaluated the detection rates. In addition, the feces of owners of the dogs infected with Giardia were examined. Giardia cysts and trophozoites were detected in 58 of the 354 dogs (16.4%) and 3 of the 34 cats (8.8%). Of the 61 animals from which cysts and trophozoites were isolated, 59 were purchased from the breeders and the other two animals had been kept for examinations in the research institute. None of the owners of the dogs had this infection. This result suggests that the possibility of human infection from contact with infected dogs or cats seems to be very low. However, attention should be paid to the possibility of cross-infection between men and animals, because it is not yet clear whether Giardia is strictly host-specific or not.