PCR-based diagnosis for detection of Leishmania in skin and blood of rodents from an endemic area of cutaneous and visceral leishmaniasis in Brazil

The technique of polymerase chain reaction (PCR) associated to hybridization was used to screen 123 samples collected from wild and synanthropic rodents captured in a cutaneous and visceral leishmaniasis endemic area in the State of Minas Gerais, Brazil. The detection of Leishmania spp in naturally infected rodents is of fundamental importance for incriminating them as possible reservoir hosts of the diseases in Minas Gerais. A total of 62 specimens belonging to wild (Thrichomys apereoides, Oryzomys subflavus, Galea spixii, Bolomys lasiurus and Wiedomys pyrrhorhinos) and synanthropic (R. rattus) rodent species were captured in different ecotopes. Blood and skin samples were submitted for PCR analyses followed by molecular hybridization with specific probes for the three Leishmania-species complexes. Fifteen samples were found positive after PCR-hybridization and identified as follows: nine belonging to the L. mexicana complex, three to the L. braziliensis complex and three to the L. donovani complex. Positive PCR results were found in 11 out of the 61 (18%) blood samples and in four out of the 62 (6.4%) skin fragments screened. R. rattus and T. apereoides were the most abundant species in the area also presenting high prevalence of natural infection. The presence of parasite DNA belonging to L. braziliensis, L. mexicana and L. donovani complexes was confirmed in several individuals of a rodent species, R. rattus. This work is the first report of the detection of L. (L.) chagasi in a naturally infected T. apereoides. The utility of filter paper as a substrate for PCR analyses and the efficacy of the procedure associated to the hybridization is emphasized.     

Cloning and analysis of a novel cDNA from Trichinella spiralis encoding a protein with an FYVE zinc finger domain

A cDNA library from Trichinella spiralis adults 3 days post-infection was screened with a cDNA probe, designated T 54, derived from a newborn larvae subtracted cDNA library. Sequence analysis showed that the positive clone contained a cDNA insert of 1464 bp in length with a single open reading frame of 1290 bp, which encoded a protein of 429 amino acids with a putative molecular mass of 49.9 k Da. Database analysis predicted the deduced protein had a leucine zipper motif and an FYVE zinc finger domain. The recombinant fusion protein was expressed and rabbit anti-recombinant protein sera reacted with a single peptide migrating at approximately 55 k Da in crude worm extract from muscle larvae, adults and newborn larvae stages.     

Uses and effectiveness of pamidronate disodium for treatment of dogs and cats with hypercalcemia

Uncorrected hypercalcemia can cause clinical signs such as polyuria, polydipsia, vomiting, diarrhea, lethargy, and depression and contributes to the development of primary renal failure and soft tissue mineralization. Treatment of hypercalcemia includes diagnosis and treatment of the underlying disease process and some combination of excracellular fluid volume expansion by administration of fluids intravenously and administration of glococorticosteroids, salmon calcitonin, and furosemide. Bisphosphonates such as pamidronate disodium also may be safe and effective in the treatment of hypercalcemia. The purpose of our study was to characterize the efficacy and safety of pamidronate in the treatment of hypercalcemia attritutable to several different disease processes in the dog and cat. Seven dogs and 2 cats were administered pamidronate at a dose of 1.05-2.0 mg/kg IV for a variety of disease processes, including neoplasia (n = 4), calcipotriene toxicity (n = 3), nocardiosis (n = 1), and idiopathic hypercalcemia with chronic renal failure (n = 1). In all the animals, IV pamidronate administration rapidly decreased serum calcium concentrations without evident toxicosis. Two animals received pamidronate several times without obvious toxicosis. On the basis of the findings in our retrospective study, pamidronate may be a safe and effective drug with which to lower both serum total and ionized calcium concentrations in patients with hypercalcemia arising from a wide variety of underlying disease processes.     

Preparation of antibodies directed to the Babesia ovata- or Theileria sergenti-parasitized erythrocytes

To investigate the surface antigens of the bovine red blood cells (RBCs) parasitized by Babesia ovata or Theileria sergenti, attempts were made to produce monoclonal antibodies (mAbs) with BALB/c mice. Comparable numbers of hybridomas producing anti-piroplasm mAbs, as well as anti-bovine RBC mAbs, were obtained from the mice immunized with B. ovata- or T. sergenti-PRBCs. However, mAbs directed to the surface of parasitized RBCs (PRBCs) were obtained only from the mice immunized with B. ovata-PRBCs, but not from those immunized with T. sergenti-PRBCs. When serum samples from the immunized mice and the infected cattle were examined, antibodies recognizing B. ovata-PRBC surface were detected in the sera against B. ovata, but analogous antibodies were undetectable in the sera against T. sergenti, despite that the sera showed substantial antibody titers to T. sergenti piroplasms. The results suggest that significant antigenic modifications occur on the surface of B. ovata-PRBCs, but not on the surface of T. sergenti-PRBCs.     

B-cell epitopes recognized by Chinese water buffaloes (Bos buffelus) on the 22 kDa tegumental membrane-associated antigen (Sj-22) of the Asiatic bloodfluke, Schistosoma japonicum.

The 22.6 kDa tegumental membrane-associated antigen of schistosomes is of recognized importance in immunity to schistosomiasis. In China, bovines are known to play an important role in the transmission of Schistosoma japonicum. Ten buffaloes (Bos buffelus) were vaccinated with a recombinant form (reSj-22) of the S. japonicum 22.6 kDa tegumental antigen (Sj-22) and the sera were used to identify and map possible linear B-cell epitopes on this molecule using a series of 18 overlapping synthetic peptides (P1-P18). Sera from all of the ten vaccinated buffaloes reacted strongly with Sj-22 in western blots and in ELISA, while sera from a further ten adjuvant (Quil A) control buffaloes did not. Four peptides (P3, P8, P9 and P10) were predominantly recognized by at least 90% of the buffalo sera. This pattern of recognition is similar to that obtained in a previous study we undertook in mice immunized with the same antigen whereby peptides 3, 8, 9 and 10 were recognized by over 80% of CBA strain mice. The peptide most frequently recognized by mice (peptide 6), and mapping to an EF-hand calcium binding domain, was recognized by six of the ten vaccinated buffaloes. The major difference between buffaloes and mice occurred with peptide 1 which was recognized very frequently by all three strains of mice tested but was only weakly recognized by three of the ten buffaloes. This study provides a valuable reference for further study on the immunity stimulated by the 22.6 kDa tegumental antigen in the murine model and a natural bovine host of Schistosomiasis japonica.     

Effects of L-carnitine fed during gestation and lactation on sow and litter performance

Multiparous sows (n = 307) were used to evaluate the effects of added dietary L-carnitine, 100 mg/d during gestation and 50 ppm during lactation, on sow and litter performance. Treatments were arranged as a 2 (gestation or lactation) x2 (with or without L-carnitine) factorial. Control sows were fed 1.81 kg/d of a gestation diet containing .65% total lysine. Treated sows were fed 1.59 kg/d of the control diet with a .23 kg/d topdressing of the control diet that provided 100 mg/d of added L-carnitine. Lactation diets were formulated to contain 1.0% total lysine with or without 50 ppm of added L-carnitine. Sows fed 100 mg/d of added L-carnitine had increased IGF-I concentration on d 60 (71.3 vs. 38.0 ng/mL, P<.01) and 90 of gestation (33.0 vs. 25.0 ng/mL, P = .04). Sows fed added L-carnitine had increased BW gain (55.3 vs 46.3 kg; P<.01) and last rib fat depth gain (2.6 vs. 1.6 mm; P = .04) during gestation. Feeding 100 mg/d of added L-carnitine in gestation increased both total litter (15.5 vs. 14.6 kg; P = .04) and pig (1.53 vs 1.49 kg; P<.01) birth weight. No differences were observed in pig birth weight variation. Added L-carnitine fed during gestation increased litter weaning weight (45.0 vs. 41.3 kg, P = .02); however, no effect of feeding L-carnitine during lactation was observed. No differences were observed in subsequent days to estrus or farrowing rate. Compared to the control diet, feeding added L-carnitine in either gestation, lactation, or both, increased (P<.05) the subsequent number of pigs born alive, but not total born. In conclusion, feeding L-carnitine throughout gestation increased sow body weight and last rib fat depth gain and increased litter weights at birth and weaning.     

The distribution of pepsinogen within the abomasa of cattle and sheep infected with Ostertagia spp. and sheep infected with Haemonchus contortus.

The effect of nematode infections on the production of pepsinogen by ruminants was investigated immunohistochemically and biochemically. Abomasal tissues were collected from parasite-naive cattle and sheep, from sheep infected with predominantly Ostertagia circumcincta, sheep infected experimentally with Haemonchus contortus and cattle infected with Ostertagia ostertagi. Pepsinogen was also assayed biochemically in homogenates of fundic mucosae from sheep infected with predominantly O. circumcincta. Infection with Ostertagia spp. parasites was associated mainly with nodular hyperplasia, resulting in increased numbers of cells that produce both pepsinogen and mucus. Measured biochemically, nodules contained more pepsinogen than adjacent more normal mucosa (p < 0.05), and this effect was largely attributable to the greater mass of nodules. Infection of sheep with H. contortus was associated with generalised hyperplasia, characterised by increased numbers of mucopeptic cells and in at least one animal with reductions in parietal cell numbers. At the same time, the zymogen granule content of chief cells was reduced. Similar changes were occasionally seen in sheep infected predominantly with O. circumcincta. Generalised hyperplasia is likely to be indicative of the presence of ambulatory parasitic stages as opposed to those confined to nodules. The potential for the enhanced production of pepsinogen by increased numbers of cells with a joint mucous cell and zymogenic cell phenotype may offset decreases in the numbers of chief cells or reductions in chief cell activity.     

八斑球腹蛛对褐飞虱的捕食作用

八斑球腹蛛对褐飞虱的种群数量有一定的控制作用。田间日捕食量为0.25～1.88头。试验室内,其功能反应可用Ⅱ型和Ⅲ型反应模型拟合;当空间容积增大时,为典型的S形Ⅲ型。为此,虫蛛比应是随褐飞虱密度、龄期结构和防治指标等变化的函数。