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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This work extends basic knowledge of tropical theileriosis in taurine and crossbred cattle. Infection of Bos taurus and Bos taurus cross Bos indicus (Sahiwal) calves with graded doses of sporozoites of Theileria annulata (Hissar), an Indian stock of the parasite, showed the following to be dose dependent in both cattle types: the time to appearance and population size of macroschizonts, microschizonts and piroplasms, time and severity of pyrexia, anaemia manifested by erythrocyte counts and haematocrit. All infections were accompanied by a prompt and severe panleucopenia. This effect was dose related in both the taurine and the Sahiwal crossbred calves. Lymphocyte counts returned to preinfection levels in the blood of animals which recovered, but death from theileriosis was characteristically accompanied by a persistent and severe lymphocytopenia. Flow cytometry using monoclonal antibodies to bovine mononuclear cells was used to identify the lymphocyte subsets involved in lymphocytopenia. The outcome of infection was dose dependent in the crossbred calves but not in taurine calves. Although the results obtained did not differ qualitatively between the two cattle types, they provided some preliminary evidence for resistance to tropical theileriosis in Sahiwal crossbred calves.
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PMID:Tropical theileriosis in Bos taurus and Bos taurus cross Bos indicus calves: response to infection with graded doses of sporozoites of Theileria annulata. 143 13

The susceptibility of N'Dama cattle (Bos taurus) to four consecutive infections with different tsetse-transmitted clones of Trypanosoma congolense was compared with that of Borans (Bos indicus). All animals were aged 13 months at the start of the study and had been born and raised free from trypanosomiasis under the same management and nutritional conditions, thereby limiting environmental factors that could have influenced susceptibility. While cattle of both breeds were equally susceptible to the establishment of trypanosome infections, the N'Damas exhibited superior resistance. Despite infection with virulent parasites, the N'Damas gained weight at the same rate as uninfected control animals, they did not develop anaemia to the extent that trypanocidal drug treatment was required, and all made a spontaneous recovery to normal haematological values within two to four months. In contrast, all the Borans needed treatment during the course of the four infections because of severe anaemia and showed markedly reduced liveweight gains. These clinical differences in the N'Damas were associated with two repeatable characteristics, namely, the ability to control parasitaemia and to 'resist' anaemia, processes that did not appear to be linked. Also in contrast to the Borans, the N'Damas were able to mount accelerated haemopoietic responses, resulting in the reduced severity of anaemia following a primary infection. These findings pose the question as to whether the ability to control parasitaemia and to 'resist' anaemia could be used as criteria for identifying resistant or trypanotolerant cattle.
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PMID:Susceptibility of N'Dama and Boran cattle to sequential challenges with tsetse-transmitted clones of Trypanosoma congolense. 192 67

Twenty cross-bred (Bos taurus X Bos indicus) calves, 7-21 days old, were infected by a ground-up tick supernate of Hyalomma anatolicum anatolicum infected with the Hisar isolate of Theileria annulata. Six calves acted as untreated controls and they all died of theileriosis within 17 days of infection. The remaining 14 calves were divided into Group A and B, each consisting of seven calves. All the calves of Groups A and B were treated intramuscularly with buparvaquone (BW 720C) on Day 11 post-infection, when clinical signs of theileriosis were apparent. Each calf received 2.5 mg BW 720 C kg-1 body weight as a single injection. In addition, each calf of Group B was given proprietary haematinics by intramuscular injection, daily for 12 days. In Group A, two calves died of cerebral theileriosis and five were clinically cured. However, four of these five calves later died of anaemia. In Group B, all the calves were clinically cured and none died during the observation period of 1 month. The parasitaemia declined to less than 1% within a fortnight of treatment. The initial declines in haemoglobin concentration and packed cell volume were halted and preinfection values were soon restored. No toxic signs attributable to treatment with buparvaquone were observed.
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PMID:Treatment of experimentally induced Theileria annulata infection in cross-bred calves with buparvaquone. 336 76

Bovine babesiosis caused by Babesia bovis remains a significant constraint to beef and milk cattle production throughout the world. Exoantigens released by the parasites in culture supernatants are a potential source of antigen to induce protective immunity. An attenuated strain of B. bovis from Brazil, catalogued as BbUFV1, was maintained in vitro by the MASP method, and exoantigen-containing supernatant fluids were collected daily to form a pool representing a 72-h culture cycle for preparation of the vaccine. Exoantigen concentration was estimated using a two-site EIA. Three groups of susceptible non-splenectomised male Bos taurus cattle, 14 months old, were used. Group A (vaccinated) received two subcutaneous immunizations with a 21-day interval of B. bovis supernatant, content 6500 EIA units of exoantigens plus 1.5 mg saponin, and Group B (adjuvant control) received two injections of adjuvant alone. Four weeks after the second immunization, Groups A, B and C (control) were challenged intravenously with 10(8) virulent parasites of a heterologous B. bovis strain. The results showed that exoantigens present in in vitro cultures can induce a high degree of protection against virulent heterologous challenge exposure. In Group A only one animal showed discrete parasitaemia; all developed a fever and slight decreases in PCV, with a rapid return to normal values. One animal of Group B died; the survivors showed fever, anaemia and parasitaemia. All animals of Group C died between 7 and 13 days after challenge. Vaccination elicited both humoral and cell-mediated immune responses. In Group A, after the challenge, the maximum antibody titer was 12,800. When vaccinated, cattle were tested at the moment of challenge for B. bovis-specific cell-mediated immunity by the monocytemigration inhibition test. A mean inhibition index of 60 +/- 0.33 was observed. Preliminary Western blot analysis of the immunogen revealed at least four proteins of molecular weight ranging between 30 and 160 kDa.
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PMID:Exoantigens of an attenuated strain of Babesia bovis used as a vaccine against bovine babesiosis. 853 77

N'Dama (Bos taurus) cattle are known to tolerate trypanosome infections, developing less severe anemia and lower parasitemia, compared to Boran (Bos indicus) cattle. Young calves were also reported to be more resistant to trypanosomiasis than adult cattle. To explore the basis for this resistance, the erythropoietic response was evaluated in four native yearling N'Dama calves and four age-matched Boran calves which developed anemia over a 140- day primary infection with Trypanosoma congolense clone IL 13E3. Similar levels of parasites were detected in the two breeds until 42 days postinfection (dpi). During the same period, a rapid and greater colony-forming units-erythroid response in the bone marrow of yearling Boran calves, compared with N'Dama calves, may explain the unusual absence of breed differences in mean packed cell volumes (PCV). However, this early erythropoietic response was transient and did not result in any rise in PCV from 70 dpi onward. In contrast, in the N'Dama calves, following the erythroid response, the mean PCV was gradually compensated from 56 dpi onward and reached 30% by 126 dpi. This period of PCV recovery coincided with low and intermittent parasitemia and a return of the erythroid progenitor levels to near preinfection values. Elevated levels of erythroid progenitors in the N'Dama calves, occurring 1 week after trypanocidal treatment, returned the PCV to preinfection values. These results suggest that the age of the Bos indicus cattle has an important impact on the early bone marrow response in primary T. congolense infection and confirmed previous suggestions of a high erythropoietic potential in trypanosome-infected young calves.
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PMID:Trypanosoma congolense: high erythropoietic potential in infected yearling cattle during the acute phase of the anemia. 861 36

A survey was carried out on 79 lactating Bos taurus/indicus cross-bred cows on three dual-purpose cattle farms to measure the blood concentration of metabolites and to evaluate possible relationships with nutritional status and productive variables. A rotational grazing system on Star grass and other tropical pastures (10-12% CP in leaves) was used and 2-3 kg/cow/day of concentrate were fed on two farms. Restricted calf suckling was used in two herds. Average milk yield sold per farm was 6 kg/day/cow and body condition scores (BCS) were between 3.0 and 3.8 on a scale of one-to-five. On two farms, the average interval from calving to conception (ICC) was more than 145 days. Mean blood concentrations of albumin, globulin, urea, beta-hydroxybutyrate and phosphorus were generally within reference values, but a significant group of cows had low levels of albumin and urea and high levels of globulin. Packed cell volume (PCV) was below normal values, with anemia in 63% of cows during the second trimester of lactation, which was negatively correlated to milk yield. The high incidence of anemia could be related to factors such as hematophagic parasites, not evaluated in this study. ICC values were negatively related to albumin level and could be associated with protein deficiency in the diet or with disease, as globulin values were high in many cows. Based on these diagnoses, an experiment was carried out on one of the farms to evaluate the influence of supplementation with 0.5 kg/cow/day of fish meal. Total milk yield was not influenced by the fish meal and reproductive efficiency was high in the two supplemental treatments. It was shown that supplementation with undergraded protein is not required in these cows.
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PMID:Blood metabolites and their relationship with production variables in dual-purpose cows in Venezuela. 1008 93

Natural resistance to African trypanosomiasis in certain Bos taurus cattle in West Africa, called trypanotolerance, may hold solutions for control of this economically crippling disease. Comparison of immune responses between trypanotolerant and trypanosusceptible cattle have shown some differences in antibody response, complement level and cytokine expression, but it is not known whether these differences are the cause of resistance. Two experiments were carried out to assess the contribution of the immune and haemopoietic systems to trypanotolerance. The production of haemopoietic chimaeras from trypanotolerant and susceptible twin calves and comparison of their responses after infection with singleton calves, allowed an assessment of the role of the haemopoietic system in trypanotolerance. An in vivo depletion of CD4 cells in the two breeds allowed an appraisal of the role of T and B lymphocytes in trypanotolerance. The results of the two experiments suggest that natural resistance comprises at least two mechanisms, an innate mechanism that controls parasite growth, and another, involving the haemopoietic system, that is able to limit anaemia. This supports the hypothesis that innate mechanisms in trypanotolerant cattle are more efficient in controlling disease, making them less reliant on antibody responses.
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PMID:Identification of mechanisms of natural resistance to African trypanosomiasis in cattle. 1207 33

Trypanosomosis, or sleeping sickness, is a major disease constraint on livestock productivity in sub-Saharan Africa. To identify quantitative trait loci (QTL) controlling resistance to trypanosomosis in cattle, an experimental cross was made between trypanotolerant African N'Dama (Bos taurus) and trypanosusceptible improved Kenya Boran (Bos indicus) cattle. Sixteen phenotypic traits were defined describing anemia, body weight, and parasitemia. One hundred seventy-seven F2 animals and their parents and grandparents were genotyped at 477 molecular marker loci covering all 29 cattle autosomes. Total genome coverage was 82%. Putative QTL were mapped to 18 autosomes at a genomewise false discovery rate of <0.20. The results are consistent with a single QTL on 17 chromosomes and two QTL on BTA16. Individual QTL effects ranged from approximately 6% to 20% of the phenotypic variance of the trait. Excluding chromosomes with ambiguous or nontrypanotolerance effects, the allele for resistance to trypanosomosis originated from the N'Dama parent at nine QTL and from the Kenya Boran at five QTL, and at four QTL there is evidence of an overdominant mode of inheritance. These results suggest that selection for trypanotolerance within an F2 cross between N'Dama and Boran cattle could produce a synthetic breed with higher trypanotolerance levels than currently exist in the parental breeds.
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PMID:Mapping of quantitative trait loci controlling trypanotolerance in a cross of tolerant West African N'Dama and susceptible East African Boran cattle. 1280 60

Trypanotolerance is the capacity of certain West-African, taurine breeds of cattle to remain productive and gain weight after trypanosome infection. Laboratory studies, comparing Trypanosoma congolense infections in trypanotolerant N'Dama cattle (Bos taurus) and in more susceptible Boran cattle (Bos indicus), confirmed the field observations. Experiments using haemopoietic chimeric twins, composed of a tolerant and a susceptible co-twin, and T cell depletion studies suggested that trypanotolerance is composed of two independent traits. The first is a better capacity to control parasitaemia and is not mediated by haemopoietic cells, T lymphocytes or antibodies. The second is a better capacity to limit anaemia development and is mediated by haemopoietic cells, but not by T lymphocytes or antibodies. Weight gain was linked to the latter mechanism, implying that anaemia control is more important for survival and productivity than parasite control. Anemia is a marker for a more complex pathology which resembles human haemophagocytic syndrome: hepatosplenomegaly, pancytopenia and a large number of hyperactivated phagocytosing macrophages in bone marrow, liver and other tissues. Thus, mortality and morbidity in trypanosome-infected cattle are primarily due to self-inflicted damage by disproportionate immune and/or innate responses. These features of bovine trypanotolerance differ greatly from those in murine models. In mice, resistance is a matter of trypanosome control dependent on acquired immunity. However, a model of anaemia development can be established using C57BL/6J mice. As in cattle, the induction of anaemia was independent of T cells but its development differed with different trypanosome strains. Identification of the molecular pathways that lead to anaemia and haemophagocytosis should allow us to design new strategies to control disease.
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PMID:Bovine trypanotolerance: A natural ability to prevent severe anaemia and haemophagocytic syndrome? 1667 82

In central and sub-Saharan Africa, trypanosomosis is a tsetse fly-transmitted disease, which is considered as the most important impediment to livestock production in the region. However, several indigenous West African taurine breeds (Bos taurus) present remarkable tolerance to the infection. This genetic capability, named trypanotolerance, results from numerous biological mechanisms most probably under multigenic dependences, among which are control of the trypanosome infection by limitation of parasitemia and control of severe anemia due to the pathogenic effects. Today, some postgenomic biotechnologies, such as transcriptome analyses, allow characterization of the full expressed genes involved in the majority of animal diseases under genetic control. One of them is serial analysis of gene expression (SAGE) technology, which consists of the construction of mRNA transcript libraries for qualitative and quantitative analysis of the entire genes expressed or inactivated at a particular step of cellular activation. We developed four different mRNA transcript libraries from white blood cells on a N'Dama trypanotolerant animal during an experimental Trypanosoma congolense (T. congolense) infection: one before experimental infection (ND0), one at the parasitemia peak (NDm), one at the minimal packed cell volume (NDa), and the last one at the end of the experiment after normalization (NDf). Bioinformatic comparisons in bovine genomic databases allowed us to obtain more than 75,000 sequences, among which are several known genes, some others are already described as expressed sequence tags (ESTs), and the last are completely new, but probably functional in trypanotolerance. The knowledge of all identified named or unnamed genes involved in trypanotolerance characteristics will allow us to use them in a field marker-assisted selections strategy and in microarrays prediction sets for bovine trypanotolerance.
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PMID:Bovine transcriptome analysis by SAGE technology during an experimental Trypanosoma congolense infection. 1713 28


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