Sheep experimentally infected with sarcocystis from dogs. I. Disease in young lambs.

Eight Polled Dorset lambs were orally inoculated with Sarcocystis ovicanis sporocysts. Two lambs that received 100,000 or 200,000 sporocysts became clinically ill, recovered, and were killed 67 and 88 days after inoculation (DAI). Numerous intramuscular cysts were found in their skeletal and cardiac muscles. Three lambs received 100,000 sporocysts, three lambs received 1 million sporocysts, and three lambs received no sporocysts. After an acute clinical illness characterized by anemia, inappetence, weight loss, fever, and reduced serum protein, all lambs that received 100,000 sporocysts died 27 to 29 DAI and all that received 1 million sporocysts died 24 or 25 DAI. Hemorrhage involving the striated muscle and visceral organs was the most apparent gross lesion. The heart appeared most severely affected. Schizonts were found in vascular endothelial cells of all six inoculated lambs. Uninoculated lambs remained healthy, and neither lesions nor parasites were found in any tissues. Dogs fed tissues containing S. ovicanis cysts produced sporocytes 11 to 37 days after feeding; cats fed similar stages produced no sporocysts. Dogs fed tissues containing schizonts produced no sporocysts.     

Pathophysiological changes in urine and blood from calves experimentally infected with Sarcocystit cruzi.

Two 8-week experiments were conducted to determine the relationships between nutritional stress and pathophysiological changes in male Holstein calves infected with Sarcocystis cruzi. Calves were infected by oral inoculation with 200 000 S. cruzi sporocysts. In the first experiment weight gain reduction was greatest in inoculated calves during weeks 4 and 5 after inoculation. Feed intake was reduced during the 5th week. Erythrocyte count was reduced during week 5 and haemoglobin was reduced during week 6. The 24-h excretion of urinary and urea nitrogen from the inoculated calves was increased by treatment. In the 2nd experiments, both the feed-restricted and inoculated calves lost weight during weeks 4 and 5; feed intake was lower from week 5 to 8 inclusive. Urine volume from inoculated calves was lower during week 8. Lower urine excretions of sodium and potassium resulted from S. cruzi inoculation. There was a non-significant trend for higher urinary zinc excretion in the inoculated group during week 4. Urine nitrogen excretion from inoculated calves was higher during week 6. The urinary excretion of 3-methylhistidine from the inoculated calves was higher during week 4 and excretion of guanine was higher during weeks 4, 5 and 8. S. cruzi has several specific pathophysiological effects on calves beyond those induced by nutritional stress.     

One-year follow-up of anti-Leishmania antibody concentrations in serum and saliva from experimentally infected dogs

The quantification of anti-Leishmania antibodies in serum and saliva by a time-resolved immunofluorometric assay is useful for the diagnosis and treatment monitoring of dogs with clinical leishmaniasis. We compared the kinetics of anti-Leishmania IgG2 and IgA antibodies in serum and saliva from 11 Beagle dogs experimentally infected with Leishmania infantum. Most dogs showed detectable concentrations of anti-Leishmania IgG2 earlier in serum (between 3 and 4 months p.i.) than in saliva (between 4 and 6 months p.i.). Overall, a high correlation between concentrations of anti-Leishmania IgG2 in serum and saliva (r = 0.853; P < 0.0001) was observed. The quantification of anti-Leishmania IgA showed less diagnostic value than IgG2, since detectable amounts of IgA were not observed in the saliva of four dogs and in the serum of one dog. In addition, a very low correlation between anti-Leishmania IgA in serum and saliva (r = 0.289; P < 0.001) was observed. Our results indicate that the antibodies against L. infantum in saliva appear approximately 1 month later than in serum, and suggest that there is a threshold for the passing of immunoglobulins from serum to saliva in dogs. These facts should be taken into consideration for a proper interpretation of saliva assays for quantification of antibodies.     

Echinostoma caproni: kinetics of IgM, IgA and IgG subclasses in the serum and intestine of experimentally infected rats and mice

The kinetics of specific immunoglobulin M, A and IgG subclasses against Echinostoma caproni (Trematoda: Echinostomatidae) were analyzed in serum and intestinal fluid of two host species (Wistar rats and ICR mice) in which the course of the infection markedly differs. In rats, the worms were rapidly expelled, whereas E. caproni evokes in mice long-lasting infection. The pattern of antibody responses in both serum and intestinal samples was different in each host species. Serum responses in mice were characterized by significant increases of IgM, IgA, total IgG, IgG1 and IgG3, but not IgG2a. In contrast, serum responses in rats showed elevated levels of IgM, probably in relation to thymus-independent antigens, and slight increases of total IgG, IgG1 and IgG2a. At the intestinal level, increases of IgM and IgA levels were observed in mice. In regard to IgG subclasses, increases in both IgG1 and IgG2a were detected. Later decreases to normal values in IgG2a were also detected. In rats, only increases in total IgG and IgG2a were found. According to our results the development of long-lasting E. caproni infections in mice appears to be associated with a dominance of Th2 responses at the systemic level and balanced Th1/Th2 responses at the local level, characterized by initial increases in IgG1 and IgG2a levels. In contrast, the worm expulsion appears to be related to increases in local IgG2a levels.     

Antigen recognition by serum antibodies in non-human primates experimentally infected with Mycobacterium tuberculosis

Tuberculosis is a significant threat to non-human primates and their caretakers. The diagnosis of tuberculosis in living non-human primates is currently based on the tuberculin skin test, which is cumbersome and sometimes inaccurate. Development of an accurate serodiagnostic test requires identification of the key antigens of Mycobacterium tuberculosis involved in antibody production. When sequential serum samples obtained from 17 cynomolgus, rhesus, and African green monkeys up to seven months since experimental infection with M. tuberculosis Erdman were screened for antibody against purified proteins of M. tuberculosis, three highly seroreactive antigens were identified. One protein, ESAT-6, reacted with sera from all infected animals. Two additional proteins, alpha-crystallin and MTSA-10, were recognized by sera from approximately 90% of infected animals. Time course analysis of antibody production indicated that the earliest response was usually to ESAT-6 alone or to ESAT-6 and other antigen(s). These results provide experimental evidence of the potential value of ESAT-6 as an antigen for use in serodiagnosis of tuberculosis in non-human primates.     

Rodents infected with Schistosoma mansoni produce cytolytic IgG and IgM antibodies to the Lewis x antigen

Schistosoma mansoni is a blood fluke that produces glyco-conjugatescontaining the Lewis x antigen (Le^x) Galß1     

Serum monitoring of IgG and IgM Babesia bigemina (Haemosporidia: Babesiidae) antibodies in calves from the Mexican tropics

Antibody dynamics (IgG and IgM) against Babesia bigemina was studied on 41 under 15 days of age from three ranches (R1, R2 and R3) in Yucatan, Mexico. Blood samples were collected every 30 days, for eight months. Sera were tested by the indirect fluorescent antibody method to detect IgG and IgM. Overall IgM seroprevalence during the calves first eight months of life was 17.1% without relation to age. Overall IgG seroprevalence was 66.8%, increasing with age. Seroprevalence in R1, R2 and R3 were 87.5%, 77.1% and 31.8% respectively. Ranches 1 and 2 were in enzootic stability. In Yucatan, the modification of management factors in ranches with enzootic instability, could increase the risk of clinical babesiosis. Cattle mobilization from ranches with enzootic instability must be strictly controlled.     

Severe thrombocytopenia in young calves experimentally infected with noncytopathic bovine viral diarrhea virus.

Seven calves between 1 week and 2 months of age were infected with a noncytopathic field isolate of bovine viral diarrhea virus (BDV) in order to evaluate the effect of BDV infection on the concentration of circulating platelets in the blood. All calves were determined to be free of BDV and neutralizing antibodies to BDV before infection. Platelet counts were performed on a daily basis over a 30-day period beginning at the time of infection. By 2 weeks postinfection, all calves showed a significant drop in the number of circulating platelets and a marked hyperplasia of megakaryocytes in the bone marrow. In three of the seven calves, thrombocytopenia was severe (less than or equal to 5,000/microliters) for 1 to 6 days. In two of these three animals, extensive petechial and ecchymotic hemorrhages were observed on all mucosal surfaces and on various internal organs during the period of severe thrombocytopenia. BDV was consistently isolated from the platelets during the early phases of the infection, and viral antigen was occasionally detected on platelets by a fluorescent-antibody assay. The results demonstrate that BDV infection is associated with decreases in platelet numbers and suggest that platelets may serve as carriers of circulating virus.     

Class IgG,IgM and IgA antibodies againstStaphylococcus aureus antigens in human serum and saliva

Using the ELISA method antibodies against the sonicate, teichoic acid (TA) and exoproducts ofStaphylococcus aureus were determined in sera and saliva of healthy individuals. Main serum antibodies against all the antigens used were shown to be class IgG antibodies. However, antigens of the sonicate stimulated significantly even the systemic IgA response. In the saliva class IgA antibodies predominated, but IgG antibody levels against TA and exoproducts approached the level of IgA antibodies. Levels of IgM antibodies against all antigens tested were low in both the serum and saliva which corresponds with the anamnestic type of response. On the basis of these results one may assume that not only IgG, but also IgA antibodies are important in the systemic immunity against staphylococcal infection and in the immunity of mucous membranes; besides IgA, even class IgG antibodies play an important role.     

Detection of IgG and IgM antibodies with ELISA technique in human trichomoniasis

The direct wet mount examination of vaginal secretion, widely applied for the diagnosis of Trichomonas vaginalis infection in woman patients, is rapid and economical, however, the sensitivity of this technique is not so high. In this study enzyme-linked immunosorbent assay (ELISA) was employed for the detection of serum anti-T. vaginalis IgG and IgM antibodies from 30 vaginal trichomoniasis patients and 30 non-infected healthy persons. The results were as follows: 1. Serum ELISA-IgG value was 0.37 +/- 0.134 (Mean +/- S.D.) in vaginal trichomoniasis patients and 0.21 +/- 0.054 in healthy controls (p less than 0.005), and the sensitivity and specificity of ELISA for serum IgG antibody were 70.0% and 96.7%, respectively. 2. Serum ELISA-IgM value was 0.33 +/- 0.177 (Mean +/- S.D.) in vaginal trichomoniasis patients and 0.11 +/- 0.051 in healthy controls (p less than 0.005), and the sensitivity and specificity of ELISA for serum IgM antibody were 70.0% and 96.7%, respectively. 3. The ELISA-IgG values showed a significant correlation with ELISA-IgM values (r = 0.77, p less than 0.005). With above results, it is assumed that ELISA is a reliable method for the diagnosis of T. vaginalis infection and simultaneous measurement of serum IgG and IgM with this technique is recommended.     

An enzyme-linked immunosorbent assay to detect serum IgG to Pasteurella multocida in naturally and experimentally infected rabbits

An enzyme-linked immunosorbent assay (ELISA) was evaluated for efficacy in detecting serum IgG against Pasteurella multocida in both naturally and experimentally infected rabbits. Blood samples and nasal cultures were taken concurrently from 58 rabbits from four conventional rabbitries. Nine rabbits from a pasteurella-free colony served as negative controls. Fifty-six rabbits were ELISA positive. Of these, 46 were P. multocida culture positive, 10 were culture negative. Two rabbits were ELISA negative, culture negative. There were no ELISA negative, culture positive animals. Serotyping by the gel diffusion precipitin test demonstrated that of the 44 typed P. multocida isolates, 57% were serotype 4, 27% were serotype 12 and 16% were serotype 3. In rabbits experimentally infected intranasally with P. multocida, serum IgG against P. multocida began to rise 21 to 33 days after infection and remained elevated until the animals were euthanized 90 days post infection. Two enzyme-linked immunosorbent assays were compared which used potassium thiocyanate extracts of different serotypes of P. multocida as antigen. The results obtained were similar, suggesting the presence of antigens common to both serotypes.     

Production of Sarcocystis cruzi sporocysts by dogs fed experimentally infected and naturally infected beef.

Twenty-one coccidia-free dogs were fed either experimentally infected or naturally infected beef in 4 experiments. The pretreatment period ranged from days 9 to 33; 7 dogs shed their first sporocysts on day 12. The full length of the patent period was not determined because most dogs were still shedding sporocysts when experiments ended on days 40 and 60. Although the patent period was long, sporocysts were not shed continuously; the total number of days sporocysts were actually shed ranged from 3 to 40. The average number of sporocysts shed by dogs fed 454 to 908 g of beef ranged from 861,000 to over 20 million. Most sporocysts were shed from days 15 to 30; peak numbers were shed on days 23 and 24. Average peak numbers ranged from 145,000 to 408,400 sporocysts. Such data can be applied to facilitate collection of sporocysts in the laboratory or to estimate the potential for transmission of infective organisms under field conditions.     

Kinetics of antibodies and antigens in serum of mice experimentally infected with Echinostoma caproni (Trematoda: Echinostomatidae)

The present study reports on the kinetics of antibodies and antigens in serum of mice experimentally infected with 75 metacercariae of Echinostoma caproni during the first 12 wk postinfection (wpi). Antibody titers in the serum of mice were determined by an indirect enzyme-linked immunosorbent assay (ELISA) using excretory/secretory (ES) antigens of E. caproni. The early detection of antibodies against ES antigens of E. caproni is feasible using indirect ELISA. Mice developed significant antibody responses at 2 wpi, and the values progressively increased until the end of the experiment. This may be related to the intestinal absorption of adult worm antigens that induces humoral responses. The presence of E. caproni circulating antigens was determined by a capture ELISA based on polyclonal rabbit antibodies against ES antigens of E. caproni. High levels of seroantigens in mice were detected by 1-2 wpi, probably because of the local inflammatory responses in mice induced by the adult worms. A drop in circulating antigen levels was observed at 9 wpi, which could reflect changes in the intestinal tissues over the course of the infection.