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1.
Infection by Trypanosoma vivax and other African trypanosomes plays an important role in reproductive disorders in male and female livestock. Outbreaks of T. vivax in the semi-arid region of northeastern Brazil are characterized by wasting disease in cattle, sheep and goats with hematological, cardiac and nervous compromises in addition to reproductive failures. Similar to reports from Africa, we previously observed a reduction in fertility rates and severe testicular degeneration and epididymitis in male sheep infected with T. vivax from this region. Although anestrus is frequently reported in goats and sheep infected with T. vivax, the effects of this infection on the female reproductive organs need clarification. In this study, we addressed this issue through a histopathological evaluation of ovarian follicular morphology and classification in goats experimentally infected with a T. vivax isolate from the Brazilian semi-arid region. The infected animals presented typical clinical signs of trypanosomosis by T. vivax, including anemia, hyperthermia, pallor of the mucous membranes, enlarged lymph nodes, and progressive loss of weight. All the infected goats remained anestrus throughout the experimental period and exhibited important disturbances in the ovaries, evidenced by reduced size and a smooth surface without follicles or corpora lutea, and abnormal follicular development. In addition, through PCR, we detected T. vivax DNA in the ovarian tissues of the infected goats. Our findings contributed to understand the female reproductive failure associated with trypanosomosis caused by T. vivax.  相似文献   

2.
《Veterinary parasitology》2015,207(1-2):17-33
Salivarian trypanosomes sequentially express only one variant surface glycoprotein (VSG) on their cell surface from a large repertoire of VSG genes. Seven cryopreserved animal trypanosome isolates known as TeAp-ElFrio01, TEVA1 (or TeAp-N/D1), TeGu-N/D1, TeAp-Mantecal01, TeGu-TerecayTrino, TeGu-Terecay03 and TeGu-Terecay323, which had been isolated from different hosts identified in several geographical areas of Venezuela were expanded using adult albino rats. Soluble forms of predominant VSGs expressed during the early infection stages were purified and corresponded to concanavalin A-binding proteins with molecular masses of 48–67 kDa by sodium dodecyl sulfate-polyacrylamide gel electropohoresis, and pI values between 6.1 and 7.5. The biochemical characterization of all purified soluble VSGs revealed that they were dimers in their native form and represented different gene products. Sequencing of some of these proteins yielded peptides homologous to VSGs from Trypanosoma (Trypanozoon) brucei and Trypanosoma (Trypanozoon) evansi and established that they most likely are mosaics generated by homologous recombination. Western blot analysis showed that all purified VSGs were cross-reacting antigens that were recognized by sera from animals infected with either T. evansi or Trypanosoma (Dutonella) vivax. The VSG glycosyl-phosphatidylinositol cross-reacting determinant epitope was only partially responsible for the cross-reactivity of the purified proteins, and antibodies appeared to recognize cross-reacting conformational epitopes from the various soluble VSGs. ELISA experiments were performed using infected bovine sera collected from cattle in a Venezuelan trypanosome-endemic area. In particular, soluble VSGs from two trypanosome isolates, TeGu-N/D1 and TeGu-TeracayTrino, were recognized by 93.38% and 73.55% of naturally T. vivax-infected bovine sera, respectively. However, approximately 70% of the sera samples did not recognize all seven purified proteins. Hence, the use of a combination of various VSGs for the diagnosis of animal trypanosomosis is recommended.  相似文献   

3.
The aim of this study was to measure the levels of inflammatory mediators in serum from horses naturally infected with Trypanosoma vivax. Banked serum samples collected during a previously reported T. vivax natural infection were used to analyze proinflammatory cytokines such as interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin 1 (IL-1), interleukin 6 (IL-6), and nitrite/nitrate (NOx) levels. We evaluated 12 serum samples from horses from a farm in southern Brazil, four of which had parasitological and molecular diagnoses for T. vivax and presented with clinical signs of disease. Cytokines were assessed by quantitative sandwich enzyme-linked immunosorbent assay, and NOx was measured using the modified Griess method. Levels of IFN-γ, TNF-α, IL-1, IL-6, and NOx were increased in serum of infected animals compared to that in noninfected animals. Therefore, infection with T. vivax caused an increase in proinflammatory cytokines and nitric oxide content.  相似文献   

4.
The present work aimed to investigate the presence of T. vivax DNA in the semen of experimentally infected goats. Twelve male goats native to the Brazilian Northeast, adults, were randomly assigned to two experimental groups: the infected group consisting of six goats infected intravenously with 0.5 mL of blood containing approximately 1.25?×?105 trypomastigotes of T. vivax, and a control group composed of six uninfected goats. After the infection, clinical examinations aiming to evaluate rectal temperature, parasitemia and hematocrit were performed. Semen samples were collected from goats by electroejaculation on the 7th, 14th and 21st days post-infection (dpi). The recombinant DNA-encoding gene encoding the L-like-specific gene for T. vivax. The infection was characterized by increased rectal temperature, high parasitemia and significant reduction of hematocrit values. Results for T. vivax DNA detection using TviCatL-PCR were positive in all semen samples from the infected group collected on 7th, 14th and 21st dpi. The presence of T. vivax DNA in 7th dpi suggests the early invasion of the parasite in the reproductive organs. Also, the finding of T. vivax DNA in all periods analyzed may suggest the continued elimination of the parasite in the semen, which may increase the chances of sexual transmission. Thus, T. vivax DNA is recorded for the first time in the semen of infected goats. Thus, these data are of great importance, since the detection of the T. vivax genetic material in the semen may point to the possibility that the parasite may be transmitted through the sexual pathway.  相似文献   

5.

Background

Ethiopia, particularly in the Northwest region, is affected by both tsetse and non-tsetse fly transmitted trypanosomosis, with significant impact on livestock productivity. The aim of this study was to determine and compare clinical findings and haematological values between experimental infections induced by Trypanosoma vivax isolates from areas of either transmission mode. Sixteen young (aged between 6 and 12 months) Zebu cattle (Bos indicus), purchased from a trypanosome-free area and confirmed to be trypanosome-negative, were randomly assigned into four groups of four animals. Groups 1, 2 and 3 were infected with an isolate from a tsetse infested or one of two isolates from a non-tsetse infested area, and group 4 was a non-infected control. All animals in the infected groups were inoculated intravenously with 2 × 106 trypanosomes from donor animals. The experimental animals were monitored for eight consecutive weeks post infection for clinical signs, parasitaemia and haematological changes in packed cell volume (PCV), haemoglobin concentration (Hgb), total red blood cell (RBC) and white blood cell (WBC) counts, differential WBC count and blood indices (mean corpuscular volume [MCV], mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration).

Results

Infection was characterized by reduced feed intake, weakness, pyrexia, parasitaemia, rough hair coat, enlarged prescapular lymph nodes, lacrimation, weight loss, pallor mucus membrane and dehydration. Body weight loss in all infected groups was significantly higher than in the non-infected control. Similarly, body weight loss was higher (P < 0.001) in animals infected with the tsetse infested isolate than with the non-tsetse infested isolates. The mean PCV, Hgb, total RBC and WBC counts were lower (P < 0.001), and mean MCV was higher (P = 0.01) in all infected groups than in non-infected control animals at different time points during the study period. Except for minor variations in haematological values, the overall changes were similar in all infected groups.

Conclusion

Clinical signs and significant reduction in haematological values in the infected groups indicated the pathogenicity of the T. vivax parasites. Pathogenicity of T. vivax from the non-tsetse infested area can be considered as nearly as important as that of its counterpart derived from the tsetse infested area.  相似文献   

6.
In rats, rabbits, sheep, and goats experimentally infected with several strains of Trypanosoma brucei, the trypanosomes were observed to localise extravascularly in connective tissues. Focal inflammatory reactions were associated with the localisation of the parasites. Trypanosoma congolense in the same species of animals and T. vivax in sheep and goats, were not observed to localise outside blood vessels. On the basis of these observations it appears that the pathogenesis of the disease caused by T. brucei differs from that caused by T. congolense and T. vivax.  相似文献   

7.
The effect of simultaneous infections with trypanosomes (Trypanosoma vivax and Trypanosoma congolense) and gastrointestinal nematodes on the productivity of sheep and goats was studied in 20 animals (6 male goats and 14 male sheep) at a farm near Maputo. The animals were divided into 4 groups which received either treatment against gastrointestinal nematodes, or against trypanosomes, or treatment against both, or no treatment at all.In two-weekly and later in weekly intervals body weight, packed cell volume, body temperature, worm egg burdens and occurence of trypanosomes in the peripheral blood were recorded. Body temperature and packed cell volume did not show the expected close relation to an infection with either trypanosomes or gastrointestinal nematodes, but the differences in the increase of body weight among the 4 groups were very considerable.Animals receiving both treatments gained an average of 13.5 kg in body weight in 40 weeks compared with 5.1 kg (surviving animals with treatment against worm parasites), 6.5 kg (surviving animals with treatment against trypanosomes) and 3.4 kg (surviving animals without any treatment). Of the last 3 groups 1 sheep (21 kg), 2 sheep (50 kg) and 1 sheep (21 kg), respectively, died.One goat, treated against gastrointestinal nematodes, but suffering from an infection with Trypanosoma vivax and Trypanosoma congolense was killed at the end of the experiment. A striking finding during the post-mortem examination was the complete hyperplasia of the red-marrow of the right and left femur.  相似文献   

8.
The present study was aimed at investigating the effect of experimental infection by Trypanosoma vivax in different stages of pregnancy, determining the pathogenesis of reproductive failure, and confirming transplacental transmission. We used 12 pregnant ewes distributed into four experimental groups: G1, was formed by three ewes infected with T. vivax in the first third of pregnancy (30 days); G2 comprised three infected ewes in the final third of pregnancy (100 days); G3 and G4 were composed of three non-infected ewes with the same gestational period, respectively. Each ewe of G1 and G2 was inoculated with 1.25 × 105 tripomastigotes. Clinical examination, determination of parasitemia, serum biochemistry (albumin, total protein, glucose, cholesterol, and urea), packed cell volume (PCV), serum progesterone, and pathological examination were performed. Placenta, amniotic fluid, blood and tissues from the fetuses and stillbirths were submitted to PCR. Two ewes of G1 (Ewe 1 and 3) presented severe infection and died in the 34th and 35th days post-infection (dpi), respectively; but both fetuses were recovered during necropsy. In G2, Ewe 5 aborted two fetuses on the 130th day (30 dpi) of pregnancy; and Ewe 6 aborted one fetus in the 140th day (40 dpi) of gestation. Ewes 2 and 4 delivered two weak lambs that died five days after birth. Factors possibly involved with the reproductive failure included high parasitemia, fever, low PCV, body score, serum glucose, total protein, cholesterol, and progesterone. Hepatitis, pericarditis, and encephalitis were observed in the aborted fetuses. The presence of T. vivax DNA in the placenta, amniotic fluid, blood, and tissues from the fetuses confirms the transplacental transmission of the parasite. Histological lesion in the fetuses and placenta also suggest the involvement of the parasite in the etiopathogenesis of reproductive failure in ewes.  相似文献   

9.
The reliability of the haematocrit centrifugation technique (HCT) was compared to the wet film, the thin and thick stained smears and the lymph node aspirate examination techniques in the diagnosis of bovine trypanosomiasis. Blood samples from cattle naturally as well as experimentally infected with T. vivax were used. In the experimental infection, HCT and thick blood smears were more efficient than the wet blood films, thin blood smears and lymph node aspirations in detecting the infection. In 753 field samples, 16 positive cases were detected by HCT. It was estimated that 62.5–75.0% of positive samples were not detected by using the wet or the thin films alone. Despite the relative unreliability of most of the methods tested, the Woo technique showed significant difference in relationship to the other techniques evaluated. It could be recommended, in combination with thick and thin films, for the diagnosis of trypanosomiasis in cattle.  相似文献   

10.
A murine monoclonal antibody specific for bovine immunoglobulin (Ig) G2 was used to develop an enzyme-linked immunosorbent assay (ELISA) to measure serum antibodies against the bovine pathogen Staphylococcus aureus. Anion exchange chromatography was used to prepare IgG2 from serum taken from a mastitic cow infected with S aureus. Specific-IgG2 antibodies binding S aureus were purified with an affinity column, using a heat-killed, low protein A strain of S aureus (M-10). Purified antibodies did not contain IgG1 or IgM and were composed of greater than 95% heavy and light chains determined on the basis of polyacrylamide gel electrophoresis. Purified IgG2 anti-S aureus antibody was used as a reference in an ELISA that (i) could detect 5.0 ng of IgG2, (ii) was specific for IgG2 antibodies binding S aureus, (iii) was precise within and among different assays, (iv) yielded 112% recovery of the purified standard, and (v) when diluted in nonspecific IgG2, generated a curve that was parallel to the standard when a sample was serially diluted. A field study with cows having elevated California mastitis test scores showed evidence of infection with S aureus, as judged by a 59% increase (P less than 0.01) in IgG2 S aureus-specific antibodies and a 25% increase (P less than 0.05) in total IgG2 antibodies. There were no differences in IgG1 concentrations in plasma. Using indirect immunofluorescence, we also confirmed that bovine polymorphonuclear cells bound IgG2 preferentially over IgG1 or IgM. Measurement of antigen-specific IgG2 antibodies may therefore be useful as an index of specific antibody immunity to mastitis-causing organisms.  相似文献   

11.
The effect of several inhibitors of complement were examined in haemolytic, bactericidal and myoplasmacidal systems with bovine serum as the complement source. It appears that although EGTA-Mg allows the alternative complement pathway to function in a haemolytic system it has an inhibitory effect on this pathway in bactericidal and mycoplasmacidal systems. Both ?-aminocaproic acid and salcyladoxime were found to be useful for distinguishing the complement pathways in bovine serum and the results of experiments with these substances indicated that bovine IgG1 and IgG2 activated bovine complement, with a mycoplasma as the target cell, by the classical pathway. Mycoplasma bovis, which unlike Acholeplasma laidlawii, does not activate the alternate pathway in gnotobiotic-calf serum, was killed by serum from cattle that had not been infected previously with this mycoplasma. In this case killing was apparently mediated by cross-reacting IgM and complement via the classical pathway.  相似文献   

12.
Bovine serum amyloid-A (b-SAA) was purified from a pool of acute phase serum using hydrophobic interaction chromatography and gel filtration. Serum was applied at a low salt concentration to a phenyl-sepharose column and SAA was eluted with a gradient of 0 to 6 M guanidine-HCI. Fractions containing SAA were pooled, concentrated and further purified by gel filtration on Superose-12. The concentration of SAA in bovine serum was quantified by an indirect ELISA using rabbit anti-human SAA and horseradish peroxidase conjugated donkey anti-rabbit IgG. Dilutions of an acute phase bovine serum sample were used as working standards. The SAA concentration of this standard was determined by comparison with purified b-SAA on SDS-polyacrylamide gel electrophoresis followed by densitometry at 590 nm. The assay detection limit was 3 μg ml−1; the intra-assay coefficient of variation was 4 per cent and interassay coefficients of variation were 5·5 per cent and 7·2 per cent at 66 and 178 μg ml−1 SAA, respectively. In calves experimentally infected with Pasteurella haemolytica type A1 the ELISA was able to detect a 10-fold increase of SAA within 24 hours of inoculation.  相似文献   

13.
Summary A micromodification of the enzyme-linked immunosorbent assay (ELISA) was evaluated for its potential application in the immunodiagnosis of bovine trypanosomiasis. Serum samples from infected and non-infected Zebu cattle and samples from Friesian cattle with experimental infections were examined for the presence of trypanosomal antibodies. There were significant differences between the microELISA values obtained with samples from infected and non-infected cattle. During the course of infection microELISA values were found to fluctuate and the antibody response varied in individual animals. The test did not distinguish between infections withTrypanosoma brucei, T. vivax andT. congolense. There were no cross-reactions between trypanosome antigens and serum samples from cattle infected withT. theileri, Theileria parva, Th. mutans, Th. annulata, Babesia divergens andAnaplasma marginale.  相似文献   

14.
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15.
Phagocytosis of Bacteroides nodosus by ovine peripheral blood leucocytes (PBL) was examined after organisms had been opsonized in sera from normal sheep, or from animals immune to, or infected with ovine footrot. Ingestion of bacteria, as assessed microscopically or by counting isotopically-labelled organisms spectrometrically was effected in suspensions by polymorphonuclear leucocytes (PMN). Opsonization of bacteria in immune serum, particularly its IgG2 isotype, enhanced the rate of phagocytosis by PMN compared with that promoted by normal serum or medium alone. Whereas IgG2 from immune serum also increased the rate of ingestion of B. nodosus by adherent PMN, IgM and IgG1 from immune serum also initiated phagocytosis of bacteria by adherent ovine monocytes. Leucocytes from normal, immune or infected sheep of different breeds ingested B. nodosus with equal facility.  相似文献   

16.
A high molecular-mass proteolytic enzyme of Actinobacillus pleuropneumoniae serotype 1, was purified from culture supernatants (CSN) by using DEAE-cellulose and sepharose-4B-gelatin chromatography. In 10% SDS-polyacrylamide gels copolymerized with porcine gelatin, the protease showed a single band of activity of > 200 kDa. However, minor molecular-mass proteolytic bands were observed when the protease was electrophoresed in the presence of either 5% beta-mercaptoethanol, 50 mM dithiothreitol, or 0.25 M urea. Furthermore, when the > 200-kDa purified protein was passed through a sucrose gradient, several bands with proteolytic activity were found: 62, 90, 190, and 540 kDa. The proteolytic activity was increased in the presence of calcium or zinc and was not affected after being heated at 90 degrees C for 5 min. Proteolytic activities were also observed in CSN from all A. pleuropneumoniae serotypes and biotypes. The purified protease hydrolyzed porcine IgA and IgG in vitro. In addition, by immunoblot the protease was recognized by serum of naturally infected pigs with serotypes 1 and 5, and by serum of pigs experimentally infected with serotypes 1, 2, 8, or 9. Serum of a pig vaccinated with CSN of a serotype 3 strain also recognized the protease, but not sera of pigs vaccinated with a bacterin (serotype 1). Proteins from CSN of all the serotypes, which were precipitated with 70% (NH4)2SO4, were recognized by a polyclonal antibody raised against the purified protease. Taken together these results indicate that an antigenic protease is produced in vivo by all the serotypes of A. pleuropneumoniae. The results indicate that proteases could have a role in the disease and in the immune response of pigs infected with A. pleuropneumoniae.  相似文献   

17.
Assays dealing with the therapeutic and prophylactic activity of isometamidium on experimental infections by Trypanosoma vivax and T. evansi were carried out. The drug was found to be highly effective against T. vivax infection in sheep and cattle in which periods of protection ranging from 118 to 195 days were achieved. No complete effects against infection by T. evansi were observed. The drug was well tolerated in sheep and cattle while side-effects were noted in treated mares. It was concluded that isometamidium could be used to prevent damage and economical losses caused by T. vivax in Venezuela.  相似文献   

18.
Intravenous injection of Berenil (3.5 mg/kg) was followed in 5 min by an increase in the jugular blood parasite count of T. congolense-infected cattle. This increase was statistically significant between 5 and 10 min post Berenil injection. The peak parasitemia reached at 8 min post Berenil was 15 times greater than the pre-treatment parasitemia. It is suggested that the rise in jugular parasitemia results from release into the general circulation of T. congolense organisms which are localized in the microcirculation. Also, because a direct trypanocidal effect of Berenil was not observed in the blood held in vitro, it is suggested that Berenil acts by making trypanosomes available to host defenses, such as the macrophage system.  相似文献   

19.
Summary

To investigate how T. vivax affects metabolism in dwarf goats, nine wethers (infection group) given alfalfa pellets ad libitum were infected intravenously and food intake was recorded up to 49 days after infection in the infection group and in the control group (n=9). Controls received the same diet, ad libitum before infection and in restricted amounts after infection in order to obtain similar intakes in the two groups. Digestible organic matter intake (DOMI) and nitrogen balance (NB) were determined during four balance trials. All animals were bled regularly to measure parasitaemia, packed cell volume (PCV) and a number of serum metabolites.

All infected animals showed symptoms typical for T. vivax infection as judged by parasitaemia, PCV and rectal temperature. Infection had a non‐uniform negative effect on food intake. Compared with controls at equal DOMI, NB was lower in infected animals, the difference being significant 4 weeks after infection. This was caused by a gradual increase in NB at equal DOMI of the control group. The NB of the ad libitum fed infected animals 2 and 4 weeks after infection was comparable to values normally found in healthy ad libitum fed dwarf goats with an equal DOMI.

NEFA values in serum were significantly elevated after infection. Except for two infected animals with an extremely low food intake towards the end of the experiment, no rise in serum ketone bodies was evident. After infection, serum protein increased, differences with controls being significant 4 and 7 weeks after infection.

It is concluded that T. vivax infection results in a decrease in energy intake and a decrease in NB up to at least 4 weeks after infection. At equal DOMI, NB of infected animals was not lower than expected for ad libitum fed healthy animals but was lower than in healthy controls on a restricted diet, probably as a result of a decrease in maintenance requirements of the latter. The data on NB and serum NEFA concentrations suggest that non‐protein energy sources are used to supply the increased energy demand as a result of infection.  相似文献   

20.
During infection with T. vivax (strain Y 58) four stages can be distinguished: (a) A prepatent period of about 1 week. (b) An acute or fulminating disease characterized by an almost continuous, fluctuating parasitaemia, a decrease of the number of thrombocytes, blood serotonin level, packed cell volume (PCV) and Hb, serum albumin and γ-globulin fractions, a low serum total lipid content and an initial rise with subsequent decrease of the blood bradykinin level. (c) A critical stage of about 4–5 weeks post infection (pi) during which the animal may develop a progressive parasitaemia and may die from disseminated intravascular coagulation. At necropsy microthrombi were a consistent and most significant observation. Accompanying features were oedema and haemorrhages in the various tissues, pulmonary oedema and lobular infarction, patches of necrosis in liver, spleen and adrenals and nephrotic changes in the kidneys. Perivascular mononuclear infiltrates, resulting in local granuloma formation (heart liver), were a constant feature. Related biochemical changes were an increase of the blood urea and serum lactate dehydrogenase levels. (d) A post-critical stage characterized by an ameliorating condition, periods with no or few trypanosomes in the peripheral blood alternating with relatively high peaks of parasitaemia. This was associated with increased blood bradykinin levels, an increase of the PCV and Hb, serum albumin and γ-globulin fractions, number of thrombocytes and blood serotonin level. A return to normal values of the serum total lipids was observed at this stage. Despite this clinical recovery of the animals, at necropsy (on days 90, 98, and 99 pi) there was a moderate to massive histiocyte-lymphocyte-plasma cellular infiltration of the heart, which led to cardiac insufficiency in two heifers.The rise of the d-amino laevulinic acid dehydratase levels of erythrocytes during the decline of the PCV and Hb values is an indication for the production of many young erythrocytes and thereby for the haemolytic nature of the anaemia.  相似文献   

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