Lipopolysaccharide binding protein in the acute phase response of experimental murine Trypanosoma brucei brucei infection

Cellular responses to lipopolysaccharide (LPS) are enhanced by LPS-binding protein (LBP). The present study investigated the acute phase response of LBP during Trypanosoma brucei brucei infection in mice. Mean plasma concentrations of LBP increased two-fold by the seventh day following infection, but decreased to intermediate levels by the 14th day. There were no significant differences in LBP concentrations of infected/antibiotic-treated and infected/untreated mice. At 35 days post-infection, the infected mice were treated with the anti-trypanosomal diminazine aceturate (Berenil^®). LBP levels of the mice then decreased to pre-infection levels within one-week. This demonstrated that LBP is an acute phase protein during murine trypanosomosis. Furthermore, opportunistic secondary bacterial infection during trypanosomosis did not seem to play an important role in the changes in plasma LBP levels. We speculate that the marked concomitant increases in plasma LBP and endotoxin-like activity following murine trypanosome infection might play an important role in the pathogenesis of trypanosomosis.     

In vitro erythrophagocytosis by cultured macrophages stimulated with extraneous substances and those isolated from the blood, spleen and bone marrow of Boran and N'Dama cattle infected with Trypanosoma congolense and Trypanosoma vivax

A standard radioactive chromium (51Cr) release assay was used to assess the in vitro phagocytosis and lysis of bovine erythrocytes by cultured splenic, bone marrow and peripheral blood monocyte-derived (PBM) macrophages isolated from healthy and Trypanosoma congolense and T. vivax-infected cattle of the Boran and N'Dama breeds. Recombinant cytokines (rHuTNF-alpha and rBolFN-gamma) and non-acid-dialysed peripheral blood mononuclear cell (PBMNC) culture supernatants stimulated these PBM for enhanced activities. The stimulants caused increases in the rate of erythrocyte phagocytosis and lysis by cultured PBM in a concentration-dependent manner. But very high stimulant concentrations caused deceased in vitro erythrophagocytosis. However, bacterial lipopolysaccharide (LPS) and acid-dialysed PBMNC culture supernatants did not cause any increase in cultured PBM erythrophagocytosis. In vitro erythrocyte phagocytosis and lysis by splenic, bone marrow and peripheral blood monocyte (PBM)-derived macrophages of Boran breed of cattle infected with Trypanosoma congolense increased from 14 days post-infection (DPI) onwards and thereafter maintained at various levels above pre-infection. Cultured splenic macrophages showed the greatest erythrocyte destruction capability while PBM-derived macrophages was the least. The rates of in vitro erythrocyte phagocytosis and lysis were higher with the cultured PBM of the Boran than those of the N'Dama cattle during T. congolense infection. The rate of in vitro erythrocyte destruction was however, similar in both groups of cattle during T. vivax infection. These results correlated positively with the dynamics and degree of anaemia developed by these groups of animals during both T. congolense and T. vivax infections. Cattle infected with T. congolense and T. vivax developed varying degrees of normocytic normochromic anaemia during infection. Boran cattle developed a more severe anaemia, and had to be treated with diminazine aceturate, than N'Dama cattle during T. congolense infection. Both breeds of cattle developed a milder but similar degree of anaemia during T. vivax infection. None of the animals were treated. The results of this study indicated a role of in vivo macrophage stimulatory factors, notably cytokines such as TNF-alpha and IFN-gamma in host's serum, as well as parasite antigens, which may act singly or in concert, in the process of enhanced erythrocyte destruction, hence anaemia by the mononuclear phagocytic system (MPS) during bovine trypanosomosis.     

The effects of diminazene aceturate on systemic blood pressure in clinically healthy adult dogs

Diminazene aceturate is a commonly used antibabesial agent. It has been postulated that diminazine may induce a decrease in blood pressure and exacerbate the hypotension presented in dogs with babesiosis. This study was undertaken to assess the effect of diminazine aceturate on the blood pressure of healthy dogs. Six healthy German shepherd dogs between 18 and 24 months of age with a mean weight of 30.4 +/- 2.75 kg were used. Blood pressure was directly measured at the following time intervals: -5, 0, 5, 10, 15, 20, 25, 30, 35, 40, 50, 60, 90 and 120 minutes after treatment with diminazine aceturate (4.2 mg/kg) intramuscularly. No statistical difference (P > 0.05) was found in blood pressure between any of the time intervals. An increase in heart rate was seen 5 minutes after the administration of diminazine aceturate but no change in blood pressure was evident. This study concluded that diminazene aceturate in its current formulation with antipyrine does not alter blood pressure in healthy adult dogs.     

Pathobiochemical mechanisms involved in the control of the disease caused by Trypanosoma congolense in African grey duiker (Sylvicapra grimmia)

The course of Trypanosoma congolense infections in African grey duiker (Sylvicapra grimmia) and sheep and goats were studied. Several parameters suggested that the grey duiker was much more resistant to trypanosomosis than sheep and goats. They showed increases in weight during infection, had a much longer pre-patent period, and their peak parasitaemia levels were about 100-fold lower than those of sheep and goats. Parasites were no longer detected in grey duiker blood 35 days after infection. Anaemia, measured as drops in packed cell volume (PCV), haemoglobin (Hb) concentration and erythrocyte (RBC) counts were not observed in the grey duiker. In contrast, sheep and goats suffered severe weight losses and had continuously high parasitaemia levels. Sheep and goats developed progressively severe normocytic normochromic anaemia and leucopenia from day 14 post-infection onwards.Serum levels of total protein, globulin and albumin of grey duiker did not change significantly throughout the course of infection, while the levels of total serum protein, globulin and gamma-globulin exhibited significant increases from day 21 post-infection onwards in sheep and goats, with peak values recorded on 28 and 35 days post-infection in sheep and goats, respectively. There were inconsistent variations in albumin levels in sheep and goats throughout the course of infection.There were no significant changes in erythrocyte activities of AST and ALT, while there were transient but significant elevations of ALP level on day 35, and GGT levels between 14 and 35 days post-infection in grey duiker. Conversely, the levels of all the enzymes were progressively depressed, especially from 14 to 49 days post-infection.In vitro erythrocyte peroxidation remained relatively unchanged throughout the period of the experiment in the grey duiker, except for slight but significant increase on day 42 post-infection. However, in vitro erythrocyte peroxidation increased significantly by between 100 and 300% of pre-infection levels from 14th to 42nd day p.i. both in sheep and goats, before returning to pre-infection levels after 14 days of treatment.Haematological values, serum and erythrocyte indices studied returned to near pre-infection levels 14 days after treatment with Berenil((R)).It is concluded that the grey duiker is inherently trypanotolerant. This is shown by its ability to control parasitaemia, suffer less severe anaemia, and to a relative degree resist pathobiochemical derangements of some serum and erythrocyte metabolites and enzymes, as well as reduction of infection-induced erythrocyte lipid peroxidase damage than sheep and goats.     

The porcine acute phase protein response to acute clinical and subclinical experimental infection with Streptococcus suis

The pig acute phase protein (APP) response to experimental Streptococcus suis (S. suis) infection was mapped by the measurement of the positive APPs C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp) and major acute phase protein (pig-MAP) and the negative APPs albumin and apolipoprotein (Apo) A-I. The aim was to elucidate the differences in the acute phase behaviour of the individual APPs during a typical bacterial septicaemic infection. Pigs were inoculated subcutaneously with live S. suis serotype 2 and blood was sampled before and on various days post inoculation (p.i.), until the pigs were killed and autopsied on day 14 p.i. Clinical signs (fever and lameness) were observed in four of the five inoculated pigs from day 2 p.i., and these pigs also had arthritic lesions at autopsy. CRP and SAA showed fast increases in serum concentrations, CRP being elevated from days 1 to 12 p.i. and peaking at 10 times the day 0-levels on day 1 p.i. SAA rose quickly to peak levels of 30-40 times the day 0-level on days 1-2 and returned to pre-inoculation level on day 5 p.i. Hp and pig-MAP showed slightly slower responses, both peaking around 5 days p.i. Hp was increased throughout the experiment with maximum levels around 10 times the day 0-levels, and pig-MAP was elevated on days 1-12 p.i. with peak levels of around seven times the day 0-levels. Apo A-I was decreased from days 1 to 8 and showed minimum levels of about 40% of day 0-levels around 1-2 days p.i. No clear pattern of changes in albumin levels could be identified. One pig, showing clinical signs on day 2 only, also showed an APP response, although of a relatively short duration, whereas three pigs presenting clinical signs for several days had a more protracted acute phase response. Remarkably, the one pig showing no clinical signs and no arthritic lesions showed an APP response comparable to that of the other, clinically affected pigs. Thus, both acute clinical and subclinical S. suis infection could be revealed by the measurement of one or more of the APPs CRP, SAA, Hp, pig-MAP and Apo A-I. The combined measurement of two or three APPs, including proteins with slow and fast kinetics, should be used to achieve the highest sensitivity for the detection of ongoing S. suis infection during a prolonged time period. A diagnostic tool based on such APP-measurements could considerably improve strategic control procedures for this important infection.     

Acute phase response to Mycoplasma haemofelis and 'Candidatus Mycoplasma haemominutum' infection in FIV-infected and non-FIV-infected cats

The pathogenicity of Haemoplasma spp. in cats varies with 'Candidatus Mycoplasma haemominutum' (CMhm) causing subclinical infection while Mycoplasma haemofelis (Mhf) often induces haemolytic anaemia. The aims of this study were to characterise the acute phase response (APR) of the cat to experimental infection with Mhf or CMhm, and to determine whether chronic feline immunodeficiency virus (FIV) infection influences this response. The acute phase proteins serum amyloid A (SAA), haptoglobin (Hp) and α-1-acid glycoprotein (AGP) concentrations were measured pre-infection and every 7-14days up to day 100 post-infection (pi) in cats infected with either Mhf or CMhm. Half of each group of cats (6/12) were chronically and subclinically infected with FIV. Marbofloxacin treatment was given on days 16-44 pi to half of the Mhf-infected cats, and on days 49-77 pi to half of the CMhm-infected cats. FIV-infected animals had significantly lower AGP concentrations, and significantly greater Hp concentrations than non-FIV-infected cats when infected with CMhm and Mhf, respectively. Both CMhm and Mhf infection were associated with significant increases in SAA concentrations, while AGP concentrations were only significantly increased by Mhf infection. Mhf-infected cats had significantly greater SAA concentrations than CMhm-infected animals. Both Mhf and CMhm infections were associated with an APR, with Mhf infection inducing a greater response. Chronic FIV infection appeared to modify the APR, which varied with the infecting Haemoplasma species.     

Kinetics of the response of four positive acute phase proteins in pigs experimentally infected with toxigenic Pasteurella multocida

In the present study, acute phase proteins (APP) responses in pigs after infection with toxigenic strain of Pasteurella multocida (Pm) were evaluated. Twelve piglets from a herd free from toxigenic Pm were used. Six of them were infected intranasally with Pm. CRP, Hp, SAA and Pig-MAP concentrations were measured using commercial ELISA tests. CRP and Hp were significantly induced from 2 days post inoculation (dpi). The concentration of Hp in inoculated pigs remained elevated until the end of the study. The concentrations of SAA and Pig-MAP increased significantly from 3 dpi, and remained elevated to 5 or 7 dpi, respectively. Strong correlations were observed between concentration of Hp or SAA and changes in the lungs. No correlations were found between levels of APP in serum and changes observed in the turbinates. On the basis of our investigation, we cannot state that evaluation of APP concentrations in serum may provide useful information about severity of atrophic rhinitis. However, the concentration of all investigated APP increased after inoculation. Thus, APP-measurements may reveal ongoing infection. Monitoring of APP concentrations in the pig herds may help to pinpoint infected animals even before clinical signs are present. If found, these "APP-high" animals may be chosen next for pathogen-specific diagnostics. Early diagnosis and therapy may prevent the infection from spreading in the herd. Moreover, monitoring of APP concentrations in serum may be useful for selecting clinically healthy pigs before integration into an uninfected herd. Future studies should focus on the possibility of distinguishing infected and non-infected pigs under field conditions.     

The pathogenesis of Babesia motasi (Wales) infection in sheep

Studies on the pathogenesis of Babesia motasi (Wales) infection following blood transfusion of infected blood to normal or splenectomised recipients showed that the intact animal is refractory to infection but that infection in splenectomised animals caused weight loss, fever, anorexia, lassitude and a macrocytic hypochromic anaemia which coincided with the peak of parasitaemia. There was an initial leucocytosis, largely due to a neutrophilia. The prepatent period following blood transfusion was 2-3 days. Unconjugated and conjugated (direct) bilirubin levels increased from pre-infection levels to peaks of 1.43 and 0.70 mg/100 ml of blood, respectively. Serum glutamic pyruvic acid transaminases (SGPT) increased slightly but serum glutamic-oxaloacetic acid transaminases (SGOT) and blood sugar (glucose) levels did not show significant changes after infection. Total serum protein levels increased temporarily and then returned to normal. Blood urea nitrogen levels increased, with biphasic peaks (76.32 and 86.29 mg/100 ml) on Days 2 and 8 post-patency. Clinical infections even in splenectomised sheep, were mild and of short duration, although recovered sheep remained carriers.     

Relapse infection after chemotherapy in goats experimentally infected with Trypanosoma brucei: pathological changes in central nervous system

Fourteen goats were experimentally infected with Trypanosoma brucei with the following results: Four animals became terminally ill 24 to 47 days after inoculation of trypanosomes and were killed for necropsy. A second group of four goats became sick, had signs of systemic trypanosomiasis, were treated with diminazine aceturate (Berenil) and recovered showing no signs of disease over observation periods of 151 to 163 days. A third group of six goats, were treated with Berenil and temporarily recovered and in 60 to 79 days after therapy; four of these goats underwent relapse infection characterized by severe central nervous system (CNS) disease. Two of these goats were necropsied 45 days after chemotherapy, before clinical signs were evident, to show early neurological lesions. In group 3 (the relapse group), the microscopic changes became more severe as relapse infection progressed. Microscopically, the central nervous system lesions were edema, hyperemia, and infiltration of plasma cells, small lymphocytes, and some macrophages in the leptomeninges, choroid plexus, and brain parenchyma. Relapse infection is discussed from the standpoint of an occult phase of the disease where parasites are protected from the effects of trypanocidal drugs by the blood-brain barrier.     

Optimal combinations of acute phase proteins for detecting infectious disease in pigs

ABSTRACT: The acute phase protein (APP) response is an early systemic sign of disease, detected as substantial changes in APP serum concentrations and most disease states involving inflammatory reactions give rise to APP responses. To obtain a detailed picture of the general utility of porcine APPs to detect any disease with an inflammatory component seven porcine APPs were analysed in serum sampled at regular intervals in six different experimental challenge groups of pigs, including three bacterial (Actinobacillus pleuropneumoniae, Streptococcus suis, Mycoplasma hyosynoviae), one parasitic (Toxoplasma gondii) and one viral (porcine respiratory and reproductive syndrome virus) infection and one aseptic inflammation. Immunochemical analyses of seven APPs, four positive (C-reactive protein (CRP), haptoglobin (Hp), pig major acute phase protein (pigMAP) and serum amyloid A (SAA)) and three negative (albumin, transthyretin, and apolipoprotein A1 (apoA1)) were performed in the more than 400 serum samples constituting the serum panel. This was followed by advanced statistical treatment of the data using a multi-step procedure which included defining cut-off values and calculating detection probabilities for single APPs and for APP combinations. Combinations of APPs allowed the detection of disease more sensitively than any individual APP and the best three-protein combinations were CRP, apoA1, pigMAP and CRP, apoA1, Hp, respectively, closely followed by the two-protein combinations CRP, pigMAP and apoA1, pigMAP, respectively. For the practical use of such combinations, methodology is described for establishing individual APP threshold values, above which, for any APP in the combination, ongoing infection/inflammation is indicated.     

Temporal changes in concentrations of serum amyloid-A and haptoglobin and their associations with weight gain in neonatal reindeer calves

Age-related changes in serum concentrations of two acute phase proteins (APPs), haptoglobin (Hp) and serum amyloid-A (SAA) were investigated in newborn reindeer calves. Repeated blood samples were obtained from 51 reindeer calves at ages 0-32 days (2-4 samples from each calf). An increase of SAA concentrations was observed during the first 2 weeks of life. However, by the end of the observation period, SAA concentrations had decreased to levels below those of the first week. Serum Hp concentrations increased throughout the observation period. SAA concentrations in the second week had a negative association with weight gain during the entire study period (4 months). These time-related changes in APP concentrations suggest that these proteins have a role in the defence and adaptation mechanisms of newborn reindeer calves. Possible reasons for these changes include the presence of APP mediators in the colostrum, exposure to environmental pathogens after birth and age-related changes in hepatic synthesis of APP.     

Effects of sub-clinical post-weaning colibacillosis and dietary protein on acute phase proteins in weaner pigs

There is an increasing body of evidence that plasma acute phase proteins (APP) can be used as a marker to assess pig health. The objective of this study was to assess whether experimentally induced sub-clinical post-weaning colibacillosis (PWC) affects the concentration of two plasma APP, i.e. haptoglobin (Hp) and C-reactive protein (CRP). Since sub-clinical PWC is sensitive to protein supply, we additionally assessed whether these APP responses are sensitive to dietary protein contents. Weaned pigs (6 groups of 9 each) were offered one of the three foods, i.e. H (230 g CP/kg), L (130 g CP/kg) or HA (23% CP with anti-microbial growth promoters). On day 5 post-weaning, pigs were either dosed with 10⁸ colony forming units of enterotoxigenic E. coli or were sham-infected. Three days later and across feeding treatments, infection had reduced feed intake. Feeding and infection treatment significantly interacted for both Hp and CRP. Infection increased Hp concentration in H and HA pigs, but not in L pigs, whilst infection increased CRP concentration to a larger extent in HA pigs than in H and L pigs. The results suggest that sub-clinical PWC leads to changes in APP profiles and that these changes may be sensitive to dietary protein contents. Usefulness of APP to describe health status in pigs may therefore need to be considered in relation to their nutritional environment.     

The pathophysiology of ovine trypanosomosis: haematological and blood biochemical changes.

The course of Trypanosoma congolense infection in sheep was followed for 96 days. Infected animals developed fluctuating parasitaemia, macrocytic normochromic anaemia and leucocytosis which was principally a lymphocytosis. Following treatment with the trypanocidal drug, diminazene aceturate at 84 days after infection, the haematological values returned to normal within 12 days. Infected sheep developed hypocholesterolaemia and hypophospholipidaemia leading to a reduction in total serum lipids. This study has shown that sheep infected with T. congolense develop anaemia, the onset of which follows the first wave of parasitaemia. The changes in blood lipids observed in infected sheep appeared to be related to the intensity and duration of parasitaemia.     

Acute phase proteins response in cats naturally infected by hemotropic mycoplasmas

Information about the acute phase proteins (APP) response in cats naturally infected with hemoplasmas and in cats co-infected with different species of hemoplasmas is lacking.This study evaluated serum amyloid A (SAA), haptoglobin (Hp) and albumin in 48 cats naturally infected with hemoplasmas, including 25 with Candidatus Mycoplasma haemominutum and 23 co-infected with different hemoplasmas agents; and in 10 healthy control cats.Infected cats had significantly higher Hp and lower albumin than controls. Symptomatic cats had significantly higher SAA and Hp, and lower albumin than asymptomatic animals, and also than controls. Asymptomatic cats had significantly higher Hp than controls. Concentrations of APP were not significantly different between single infected and co-infected cats.According with these results, hemoplasmosis should be considered when alterations in APP are detected in diseased cats with compatible clinical signs. Furthermore, a subclinical infection should be considered in apparently healthy cats from endemic areas with increased Hp.     

Clinical and haematological findings in 70 naturally occurring cases of canine babesiosis

Natural cases of Babesia canis infection in Nigerian dogs were encountered over a two-year period. Over 70 per cent of the dogs were less than or equal to one year of age. The hyperacute and acute forms of the disease were encountered in dogs as young as four weeks. The acute form of the disease was most common. Consistent clinical signs of the acute form included abnormal appetite, lethargy, fever, anaemia, generalised lymphadenopathy, splenomegaly, emaciation and icterus. Anaemia was of the regenerative type in all cases while neutrophilic leucocytosis was mainly observed in hyperacute cases. Four dogs with hyperacute disease died despite treatment while all other dogs recovered following single dose (3–5 mg/kg) treatment with diminazene aceturate. The results of this study indicate that hyperacute babesiosis in dogs should be considered more frequently by veterinarians.     

Serum haemolytic complement activity and C3 levels in bovine trypanosomosis under natural conditions of challenge--early indications of individual susceptibility to disease

Twenty-five Baoule (Bos taurus) and 12 Zebu (Bos indicus) cattle, which were part of an experiment aimed at characterizing cattle for resistance to trypanosomosis under natural challenge in Burkina Faso, were monitored for complement levels. Total haemolytic activity of the alternative complement pathway and C3 in sera taken weekly were estimated. The results were analysed in relation to the course of the disease, parasitological data, packed red cell volume (PCV) and body weight. All the animals became infected with Trypanosoma vivax and/or T. congolense. The Zebu had to be treated with Berenil (Diminazene aceturate, Hoechst, W. Germany) after a mean period of 5 weeks of infection, whereas 7 of the 25 Baoule remained in good condition throughout the experiment. The remaining 18 Baoule required treatment after a variable period of infection. There was a decrease in haemolytic complement activity (HC') as well as in C3 levels, which coincided with the first detection of parasites in the blood. The titres in the Zebu fell to 10-20% of pre-infection level within 2-3 weeks and they showed no tendency towards regaining normal levels. The drop in complement in the Baoule was less pronounced and was in most cases followed by an increase approaching normal values. In these animals, the complement level in early infection was found to depend on the intensity of parasite load and on the control potential of each individual. There was a significant correlation between minimum complement activity (min. HC'), minimum C3 (min C3) and minimum PCV (min.PCV) in early infection. These three parameters correlated with individual resistance and might, therefore, be useful criteria for the identification of the most resistant individuals within a trypanotolerant breed.     

The role of acute phase proteins in diagnosis and management of steroid-responsive meningitis arteritis in dogs

Acute phase proteins (APPs) have become an important tool in the diagnosis, management and prognosis of inflammatory diseases in humans and are developing a similar utility in domestic species. Steroid-responsive meningitis arteritis (SRMA) is a well-recognised inflammatory disease of the dog, the diagnosis of which remains unsatisfactory based on clinical criteria and non-specific laboratory investigations. In this prospective pilot study the authors examined the acute phase response throughout the course of SRMA in serum and cerebrospinal fluid (CSF) by evaluating three key stages in disease management: presentation, treatment response and putative relapse.Serum APPs were found to be of value in supporting the diagnosis of SRMA and monitoring its treatment. C-reactive protein (CRP), serum amyloid-A (SAA), alpha-1-acid glycoprotein (AGP) and haptoglobin (Hp) all exhibited an increase above our laboratory reference range in nine patients at initial presentation. During treatment APPs decreased significantly compared to presentation except Hp which increased (Wilcoxon–Signed–Rank-test: CRP, SAA and AGP P < 0.05). Serum CRP and SAA were also found to be of clinical value in the identification of putative relapse (seven cases), particularly in the light of unperturbed CSF parameters where APP concentrations were elevated. CSF APPs were found to be less reliable markers in the management of this disease. The results indicate that SRMA causes a significant APP response in dogs, which although not disease specific, is of value in supporting the diagnosis of SRMA.     

High milk neutrophil chemiluminescence limits the severity of bovine coliform mastitis

Polymorphonuclear neutrophil (PMN) function changes during mastitis. To investigate the contribution of milk PMN to the severity of Escherichia coli (E. coli) mastitis, chemiluminescence (CL) of blood and milk PMN and their efficiency to destroy coliform bacteria in the mammary gland were examined following the induction of E. coli mastitis in early lactating cows. To better assess and define the degree of mastitis severity, cows were classified as moderate and severe responders according to milk production loss in the non-infected quarters at post-infection hour (PIH) 48. There was an inverse relationship between pre-infection milk PMN CL and colony-forming units at PIH 6. In moderate cows, the pre-infection blood and milk PMN CL was approximately 2-fold higher than that of severe cows. The probability of severe response increased with decreasing pre-infection PMN CL. At the beginning of the infection blood and milk PMN CL was consistently higher, and milk PMN CL increased faster after infection in moderate cows. At PIH > 48 milk PMN CL in severe cows exceeded that of moderate cows. The somatic cell count (SCC) in moderate cows increased faster than colony-forming units, whereas in severe cows the results were reversed. The kinetics of CL activity for blood and milk PMN before and during the early phase of infection confirmed an impairment in PMN CL activity for severe responding cows. High pre-infection blood and milk PMN CL and the immediate increase of milk PMN CL and SCC after infection limited bacterial growth thereby facilitating the recovery of E. coli mastitis in moderate cows. Our study strengthens the idea that pre-existing milk PMN (a static part of the udder's immune defense) functions as a "cellular antibiotic" before and during infection, and low milk PMN CL is a risk factor for bovine coliform mastitis.     

Elevation of muscle and plasma 3-methylhistidine as a result of turkey coccidiosis

To assess muscle breakdown during avian coccidiosis, the level of the non-metabolizable amino acid 3-methylhistidine (3MH) was determined in muscle and plasma from turkey poults that received an infection with a field isolate containing a mixture of Eimeria species. The effect of increased levels of parasitism was evaluated at 6 days postinoculation (DPI) in birds receiving 2.5 x 10(4), 1 x 10(5), or 2 x 10(5) oocysts each. The changes in 3MH levels during recovery from acute infection were assessed at 6-29 DPI in animals given 1.9 x 10(5) oocysts per bird. In some experiments, uninoculated birds given the same amount of feed as infected birds (pair fed) were used to determine the impact of feed deprivation on weight loss and 3MH levels. Infected birds had significantly elevated plasma and muscle 3MH at 6 DPI after a single dose of Eimeria oocysts. The plasma and muscle 3MH returned to control levels after 14 DPI. The 3MH levels increased with increased dose of oocysts. Plasma and muscle 3MH levels were well correlated, and an inverse curvilinear relationship between weight gain and plasma 3MH concentrations levels was observed. Plasma and muscle 3MH levels were significantly elevated in pair-fed birds, but 3MH levels in infected birds were increased by 30% over pair-fed birds. The results suggested that muscle breakdown, as assessed by plasma and muscle levels of 3MH, increased during the acute stage of Eimeria infection in turkey poults.     

Bovine serum transferrin concentration during acuteinfection with Haemophilus somnus

A novel, competitive immunoassay based on time-resolved fluorimetry was developed, and used to measure the serum concentration of bovine transferrin during acute Haemophilus somnus pneumonia. Upper and lower limits of normality were established using serum from healthy cattle (3.72–1.37mgmL⁻¹). Following experimental infection with Haemophilus somnus, transferrin concentration was depressed in all calves but recovered to pre-infection levels in groups of calves which had either no lesions, or mild lesions at necropsy between 5 and 6 days after infection. In a third group, which developed extensive lesions, the transferrin concentration remained depressed. Transferrin levels remained within the normal range for all calves during the experimental period. Those calves which had low transferrin concentrations pre-infection, developed extensive lung lesions following experimental infection with Haemophilus somnus.