Hematological and biochemical studies of stephanofilarial dermatitis in naturally infected cattle of West Bengal, India

This experimental study was conducted to assess the alterations in hematobiochemical values of cattle infected with stephanofilarial microfilariae. Hematological studies of infected cattle revealed significant (P < 0.05) decrease in Hb%, PCV and TEC values whereas TLC values were significantly (P < 0.05) increased. There was insignificant increase in lymphocyte concentration (%), significant (P < 0.05) increase in eosinophil concentration (%) and insignificant decrease in neutrophil concentration (%) in infected cattle in relation to control animal. Biochemical studies revealed that the values of glucose, alkaline phosphatase, AST and ALT were significantly (P < 0.05) increased in infected cattle than control cattle. However, the value of total serum protein was not affected.     

Acquired methemoglobinemia in anemic cattle infected with Theileria sergenti.

To investigate the mechanism of anemia accompanying Japanese bovine theileriosis, we examined whether production of methemoglobin (MetHB), an indicator of erythrocyte oxidation, was associated with anemia in cattle experimentally infected with Theileria sergenti. The percentage of MetHB, which is an oxidized form of hemoglobin, increased according to the onset of anemia. During severe anemia, high levels of acquired methemoglobinemia were observed in all infected cattle. A significant correlation (r=-0.649; P<0.01) between an increase in MetHB concentration and a decrease in packed cell volume (PCV) was observed. It was considered that hemoglobin oxidation may be one of the aggravating factors of anemia in T. sergenti infection.     

Elevated Serum Cardiac Troponin I in Cattle with Theileriosis

Background

Theileria annulata is a blood parasite affecting ruminants. Hemolytic anemia, secondary hypoxia, and vasculitis are the most important features of tropical theileriosis.

Objectives

Evaluation of electrocardiographic findings and changes in cardiovascular biochemical markers including cTnI concentrations in cattle naturally infected with theileriosis in the absence of acute cardiac failure.

Animals

Ninety adult Holstein cattle (>1 year) with clinical and laboratory evidence of theileriosis and 30 healthy cattle served as controls.

Methods

Case‐control study in which blood samples were collected and randomized after clinical, hematologic, parasitologic examination and laboratory confirmation and electrocardiographic recording on all animals, serum cardiac troponin I (cTnI), aspartate aminotransferase (AST), and creatine kinase‐MB (CK‐MB) were evaluated.

Results

Serum concentration of cTnI was significantly higher in cattle with theileriosis (mean: 0.028 ng/mL; range: 0.005–0.21 ng/mL; control mean: 0.011; range: <0.005–0.09 ng/mL; P = .003). There was significant correlation between serum level of cTnI and PCV (r = ?0.257; P < .001) and also between cTnI and parasitemia (r = 0.515; P < .001). Mean serum activities of AST and CK‐MB were 107 ± 46 and 301 ± 103 U/L in sick animals, which were significantly higher than healthy cattle (P = .002 and P = .041, respectively). There were no pathologic arrhythmias detected in sick animals.

Conclusions and Clinical Importance

Theileriosis is a risk factor for elevation of cardiac biomarkers in naturally infected Holstein cattle. Severity of anemia and parasitemia might contribute to the pathophysiology of myocardial damage. The prognostic significance of increased serum cardiac troponin I concentrations in cattle with hemolytic anemia merits further investigation.

     

Theileria orientalis MPSP types in Australian cattle herds associated with outbreaks of clinical disease and their association with clinical pathology findings

Between September 2010 and November 2011, 350 EDTA blood samples were received from 73 Australian cattle herds, as cases suspected to be infected with Theileria orientalis. Beef cattle were predominantly affected, with Angus and Angus-crossbred cattle representing 48% of smear positive samples examined. DNA extracts were tested in conventional polymerase chain reaction (PCR) assays for genes encoding the p32, Ikeda, Chitose and Buffeli major piroplasm surface proteins (MPSP). PCR findings were compared with results of clinical pathology examinations of stained blood smears for parasitaemia and packed cell volume (PCV). PCR testing was much more sensitive than clinical pathology examinations in detecting T. orientalis infections, and concurrent testing of neat and diluted extracts gave significantly more PCR positive results than testing of neat extract alone. Significant associations and correlations were shown between PCR results of p32 and Ikeda assays with PCV levels indicative of anaemia, and with the level of parasitaemia estimated by smears. A high proportion of samples had concurrent Ikeda and Chitose infection, and significantly more clinical cases of theileriosis were associated with the Ikeda MPSP type as the sole infection, compared with sole infection with types Chitose or Buffeli. The findings indicate Ikeda type organisms were significantly associated with clinical parameters of theileriosis in cattle herds in eastern Australia, and that this type is most likely to be responsible for outbreaks of theileriosis experienced in affected Australian herds. In New South Wales, 11 of 14 regulatory districts yielded Ikeda positive samples, with five (Mid-Coast, Cumberland, Central North, Hume and Lachlan) containing 234/307 (76%) of the Ikeda positive samples.     

Preoperative prognostic indicators in cattle with abomasal volvulus

A prospective study evaluating preoperative prognostic indicators in 80 cattle with abomasal volvulus was done. Surgical correction of the abomasal volvulus was performed in all animals. After surgery, cattle were categorized into 3 groups: productive (acceptable milk production or appetite, n = 59), salvaged (poor milk production or appetite, n = 10), and nonsurvivors (n = 11). Mean values for study variables did not differ significantly between salvaged and nonsurvivor groups. Cattle in these 2 groups were combined to form a nonproductive group, which was compared with the productive group. Productive cattle had a significantly lower preoperative heart rate than nonproductive cattle, were less dehydrated, had lower serum alkaline phosphatase (ALP) activity and serum creatinine concentration, more frequent rumen contractions, higher serum Na+ and Cl- concentrations, and had been inappetent for a shorter period. Significant differences were not detected in blood pH, base excess, anion gap, PCV, and serum K+ concentrations between the 2 groups. Feces from nonproductive cattle tended to be reduced in volume and were significantly darker. A number of preoperative prognostic indices were evaluated by calculating the sensitivity, specificity, and positive predictive value (+PV) of each variable and by using logistic regression. Positive predictive values were generally higher in identifying productive cattle than nonproductive cattle.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute phase response in cattle infected with Anaplasma marginale

This study was undertaken to evaluate the acute phase responses via the assessment of the concentration of serum sialic acids (total, lipid bound and protein bound), inflammatory mediators (IFN-γ and TNF-α) and acute phase proteins (Hp and SAA) in 20 adult crossbred cattle naturally infected by Anaplasma marginale. The infected animals were divided into 2 subgroups on the basis of parasitemia rate (<20% and >20%). Also, as a control group, 10 clinically healthy cattle from the same farms were sampled. Our data revealed significant decreases in red blood cell count (RBC), hematocrite (PCV) and hemoglobine (Hb) in infected cattle compared to healthy ones. Conversely, the concentrations of Hp, SAA, ceruloplasmin, fibrinogen, serum sialic acids and the circulatory IFN-γ and TNF-α were increased in the diseased cattle (P<0.05). In addition, it was evident that the progression of parasitemia in infected cattle did not induce any significant alterations in the hematological indices (RBCs, PCV and Hb) and the concentrations of Hp, SAA, ceruloplasmin and fibrinogen. SAA was the most sensitive factor to change in the diseased cattle. Therefore, increase in SAA concentration may be a good indicator of inflammatory process in cattle naturally infected with Anaplasma marginale.     

牛瑟氏泰勒虫病致病机理的研究进展

牛瑟氏泰勒虫病是由蜱传染的一种血液原虫病。近年来,随着养牛业的发展,牛瑟氏泰勒虫病的发生呈上升趋势,尤其是引进牛和改良牛的发病率和致死率均较高,给养牛业带来了巨大的经济损失。本文对近年来牛瑟氏泰勒虫病的病原体、流行病学、病理学和致病作用等与此病的致病机理相关的方面的研究进展作一总结,以便广大兽医工作者对此病有更加深入的认识。     

BSE Risks for Humans Consuming Beef and Beef Products: How Any Risks Are Managed

The biochemical parameters were studied in adult and young Friesian cattle naturally infected with Theileria annulata in the Qassim Region, Saudi Arabia. Forty-three clinical cases of tropical theileriosis were studied, together with 40 clinically healthy Friesian cattle. Cattle clinically infected with T. annulata had significantly lower serum total protein, albumin, globulin, creatinine, calcium, phosphorus, magnesium, potassium, iron and copper concentrations and significantly higher AST activity and bilirubin concentration than the healthy cattle.     

Serum biochemical and hematologic values of normal and Mycobacterium bovis-infected American bison

Hematologic and serum biochemical tests were used to monitor the health of 3 groups of bison in an experimental study of tuberculosis. Bison were randomly assigned to Mycobacterium bovis-infected, M. bovis-sensitized, and uninfected control groups. Hematologic measurements included total and differential leukocyte counts, hemoglobin (Hb), packed cell volume (PCV), fibrinogen, and plasma proteins. Biochemical tests included serum urea nitrogen, creatinine, aspartate amino transferase, sorbitol dehydrogenase, serum calcium, and serum phosphorus. There were no significant differences (P = 0.05) in any test values between groups of bison. The bison data were combined and compared to similar data of cattle. The mean values for PCV and Hb were higher than values (PCV 24-46%, Hb 8-15 g/dl) for cattle. Mycobacterium bovis-infected bison had a slight increase in the number of blood monocytes and lymphocytes when compared to the uninfected bison but were within the normal ranges for bison and cattle. Other hematologic parameters were within normal ranges reported for cattle. Creatinine levels in all bison were above the normal range (1.0-1.5 mg/dl) for cattle. Phosphorus levels for M. bovis-infected and M. bovis-sensitized bison exceeded the normal range (5.6-8.0 mg/dl) reported for cattle. The level for uninfected bison was near the upper limit of normal for cattle. Mean values for other serum biochemical tests were within the normal ranges reported for cattle.     

Alterations of erythrocyte antioxidant mechanisms: antioxidant enzymes, lipid peroxidation and serum trace elements associated with anemia in bovine tropical theileriosis

In order to investigate the alterations of erythrocyte protective antioxidant mechanisms, lipid peroxidation and trace elements associated with anemia in bovine tropical theileriosis, an infected group comprised of 50 crossbred Holstein cattle, about 1-2 years old, naturally infected with Theileria annulata, were divided into 4 subgroups according to their parasitemia rates (<1%, 1-3%, 3-5%, >5%) and also 10 healthy cattle as control were selected. Blood samples were taken and hematological parameters, the activities of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase and serum concentrations of some antioxidant trace elements (copper, iron, zinc, manganese and selenium) were measured. As an index of lipid peroxidation, the level of Malondialdehyde (MDA) was also determined. The results showed a conspicuous decrease in the activities of SOD, GPX and catalase (P<0.01), and a significant decrease in the serum concentrations of Cu, Zn, Mn and Se in cattle with higher than 1% parasitemia (P<0.05) compared to the control. In addition, remarkable elevations in the MDA level (P<0.01) and serum concentration of iron (P<0.05) were observed in the infected animals. These findings pointed to the occurrence of exacerbating oxidative injuries to erythrocytes during parasitemia. Furthermore, it can be concluded that infection with T. annulata can interfere with protective antioxidant mechanisms of RBCs against oxidative damages, which promote the development of anemia.     

Prognostic indicators for canine monocytic ehrlichiosis

In order to identify prognostic factors for survival in canine monocytic ehrlichiosis (CME), clinical records of 40 cases of CME were retrospectively studied. The dogs were assigned as survivors (n=21) and non-survivors (n=19), and their signalment, anamnesis, clinical and clinicopathological signs, and treatment protocols were compared. Pale mucous membranes, bleeding tendencies and weakness were more prevalent in the non-survivors compared to the survivors. Dogs in the non-survivor group had significantly lower white blood cell (WBC), hematocrit (HCT), and platelet (PLT) counts. Pronounced pancytopenia (WBC < 4 x 10(3) microL(-1); HCT < 25%; PLT < 50 x 10(3) microL(-1)) was found as a risk factor for mortality. In this study, severe leucopenia (WBC < 0.93 x 10(3) microL(-1)), severe anemia (PCV < 11.5%), prolonged activated partial thromboplastin time (APTT>18.25s) and hypokalemia (K<3.65 mmol/L) were each found to predict mortality with a probability of 100%. In contrast, WBC counts above 5.18 x 10(3) microL(-1), platelet counts above 89.5 x 10(3) microL(-1), PCV > 33.5%, APTT < 14.5s and serum potassium concentration above 4.75 mmol/L, each provided 100% prediction for survival. These prognostic indicators can be easily obtained at presentation, are inexpensive, and may be useful aids when treatment and prognosis are being considered.     

Hematology analyzer comparison: Ortho ELT-8/ds vs. Baker 9000 for healthy dogs,mice,and rats

A Baker 9000 hematology analyzer (electronic impedance) was purchased to replace an Ortho ELT-8/ds analyzer (laser optics) due to discontinued technical support. An analytical comparison of hemograms from healthy dogs, rats, and mice was made from paired disodium ethylenediamine tetra-acetate anticoagulated blood samples. Both instruments were calibrated with human blood products, and the ELT-8/ds hematocrit (HCT) was calibrated to a spun packed cell volume (PCV) for each species. For Beagle dogs (n = 49), Baker 9000 mean platelet (PCV) counts had a negative bias of -89 X 10(3)/microliter when compared to ELT-8/ds values. Mean +/- standard error manual PLT counts compared well with Baker 9OOO values for dogs (n = 10): 369 +/- 28 vs. 367 +/- 27 X 10(3)/microliter; r = 0.93. For CD-1 mice (n = 44), Baker 9000 mean white blood cell (WBC) counts had positive biases of 1. 1 X 10(3)/microliter when compared to ELT-8/ds and 0.5 X 10(3)/microliter when compared to hemacytometer counts. Diluted microsamples using the predilution mode on the Baker 9000 compared well with undiluted samples for mice. For Sprague-Dawley rats (n = 70), Baker 9000 mean WBC, red blood cell (RBC), and PLT counts had absolute biases of 0.8 X 10(3)/microliter, -1.09 X 10(6)/microliter, and -357 X 10(3)/microliter, respectively, when compared to ELT-8/ds values. Baker 9000 RBC, WBC, and PLT counts from rats compared well with reference hemacytometer counts. The Baker 9000 HCT determination for rats had an absolute negative bias of 6% when compared to the ELT-8/ds values or spun PCV. The Baker 9000 required whole blood calibration to PCV for accurate determination of HCT for rats. The biases between analyzers may be due to inherent physical differences between the analytical methods and/or the calibration techniques.     

Development of a hamster model of Chlamydophila pneumoniae infection

The purpose of the study was to evaluate haemostatic function in cattle with abomasal displacement (AD) and to reflect the occurrence of disseminated intravascular coagulation (DIC). Ten adult cattle with left displacement of abomasum (LDA) (group I), 10 adult cattle with right displacement of abomasum with volvulus (RDA) (group II) and 10 clinically healthy adult cattle (control group) were used as material. Numbers of platelets (PLT) and coagulation tests (activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), serum fibrin/fibrinogen degradation products (FDPs), fibrinogen) were measured before the surgical treatment of cattle with LDA and RDA. APTT was prolonged only in group II compared with the control and group I (p<0.05). However, when the individual values of coagulation profiles of each cow were evaluated, two cattle in group I and three cattle in group II had at least three abnormal coagulation profiles, which reflect the occurrence of DIC. These cattle died after surgical treatment. The two cattle with LDA had abnormal APTT, FDPs and PLT values; three cattle with RDA had abnormal APTT, PT, TT, FDPs and PLT values. APTT (5 cases), FDPs (5 cases) and thrombocytopenia (5 cases) were the three most common abnormal tests on coagulation profile in the cattle with LDA and RDA. The results of the study indicate that cattle with AD had a spectrum of haemostatic dysfunction and that DIC was a significant risk factor for mortality.     

A study about tick vectors of bovine theileriosis in an endemic region of Iran

The aim of this study was to determine the population of ticks in infected cattle and to identify the tick vectors of bovine theileriosis in an endemic area of Iran from 1998 to 1999. A total of 120 suspected cattle suffering from theileriosis were clinically examined and investigated for the presence of Theileria annulata in blood smears and the presence of any tick species on the body of cattle. In this study, 680 ticks were collected from 107 cattle infected with T. annulata. The prevalence of ticks infesting cattle was 92.35% Hyalomma anatolicum excavatum, 5.14% H. marginatum marginatum, 1.17% H. asiaticum asiaticum and 1.32% Rhipicephalus sanguineus. The examination of 510 tick salivary glands revealed that 51% of H. a. excavatum and 1.3% of H. a. asiaticum were infected with sporozoites of T. annulata.     

Tropical theileriosis in Bos taurus and Bos taurus cross Bos indicus calves: response to infection with graded doses of sporozoites of Theileria annulata.

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.     

Status of Lipid Peroxidation,Some Antioxidant Enzymes and Erythrocytic Fragility of Crossbred Cattle Naturally Infected with <Emphasis Type="Italic">Theileria annulata</Emphasis>

Erythrocytic lipid peroxidation, activities of some antioxidant enzymes and osmotic fragility of red blood cells was studied in adult (>1 year) crossbred cattle naturally infected with Theileria annulata. Twenty clinically healthy animals (group I) and 15 clinical cases (group II) of tropical theileriosis were selected. Cattle suffering from theileriosis had significantly higher (p<0.01) erythrocytic lipid peroxidation and osmotic fragility. Activities of antioxidant enzymes, viz. glucose-6-phosphate dehydrogenase (G6PD) and glutamate peroxidase (GPx) were also significantly increased (p<0.01) in group II. However, superoxide dismutase and catalase did not show significant changes. The results indicated that infection with theileria led to increased oxidative stress to the animals, and even a significant rise in the activities of antioxidant enzymes. G6PD and GPx could not lower this oxidative stress. However, the increase in the activities of antioxidant enzymes pointed towards the body’s defence mechanism against lipid peroxidation during oxidative stress in theileriosis.     

Serum Progesterone Concentrations and Blood Neutrophil Alkaline Phosphatase Activity in Cows Following Normal and Abnormal Parturition

Serum progesterone concentrations and alkaline phosphatase (ALP) activity of blood neutrophils were determined in 3 groups of cows (n = 5 each) on days 1 and 2 and then at 3-day intervals up to 32 days post-partum. Group I cows had a normal delivery, Group II cows had dexamethasone-induced parturition and Group III cows were subjected to a caesarian section. All cows in Group III and 2 cows in Group II retained their fetal membranes. Mean serum progesterone concentrations declined the second day after calving (to < 0.67 ng/ml) and remained at low levels (< 0.54 ng/ml) throughout the observation period, except for the values in Group III, which were elevated on day 16 (0.94 ng/ml), declined again on day 26 (0.46 ng/ml) and peaked (1.05 ng/ml) on day 32 portpartum. Significant (P < 0.01) differences were found between serum progesterone concentrations on day 1 and on each of the other sampling days in Groups I and III. Day X parturition group interaction was significant (P < 0.05) for the progesterone concentrations. No significant differences were found between the overall means of ALP activity of blood neutrophils in the 3 parturition groups nor between days of the experiment. No significant correlation was found between serum progesterone concentrations and ALP activity values of blood PMN during the first 32 days post-partum. Inhalt: Serum Progesteron Konzentrat und Aktivität der alkalischen Phosphatase in neutrophilen Blutzellen bei Küken mit normalem und abnormalen Geburtsverlauf Serum-Progesteronkonzentrationen und alkalische Phosphatase- (ALP) Aktivität von neutrophilen Granulozysten, nach der Abkalbung am Tag 1 und 2 und dann im Abstand von 3 Tagen bis zum 32. Tag p.p. bei Kühen untersucht, die in drei Untersuchungsgruppen (n = 5) eingeteilt waren. Gruppe I kalbte normal ab, in Gruppe II wurde die Geburt durch Dexamethason eingeleitet, und Kälber der Gruppe III wurden via Kaiserschnitt gewonnen. Alle Tiere der Gruppe III und 2 Kühe der Gruppe II wiesen Nachgeburtsverhaltungen auf Der mittlere Serum-Progesterongehalt sank am 2. Tag p.p. auf < 0,67 ng/ml ab und blieb auf niederigem Niveau (< 0,54 ng/ml) während der gesamten Untersuchungs-periode. Lediglich in Gruppe III, mit erhöhten Werten (0,94 ng/ml) an Tag 16 p.p., sanken die Werte wieder an Tag 26 p.p. (0,46 ng/ml) und erreichten einen Maximalwert an Tag 32 p.p. mit 1,05 ng/ml. Signifikante (P 0,01) Unterschiede in der Serum-Progesteronkonrentration wurden zwischen Tag 1 p.p. und allen anderen Untersuchungstagen in den Gruppen I und III gefunden. Interaktionen zwischen den Gruppen für Tag X waren signifikant (P 0,05). Keine signifikanten Unterschiede wurden für den Gesamtmittelwert der ALP-Aktivität in den neutrophilen Granulorysten zwischen den Gruppen und im Vergleich der Untersuchungstage gefunden. Es wurden auch keine signifikanten Korrelationen zwischen den Serum-Progesteronkonzentrationen und der ALP-Aktivität der PMN während der ersten 32 Tage p.p. nachgewiesen.     

Field study on nematode resistance in Nelore-breed cattle

The present study evaluated Nelore cattle with different degrees of resistance to natural infections by gastrointestinal nematodes. One hundred weaned male cattle, 11-12 months of age, were kept on the same pasture and evaluated from October 2003 to February 2004. Faecal and blood samples were collected for parasitological, haematological and immunological tests. In February 2004, the 10 most resistant and the 10 most susceptible animals were selected based on individual means of nematode faecal egg counts (FEC). Such animals were slaughtered for worm burden determination and nematode species identification. The repeatability estimates for FEC (+/-S.D.), log-transformed FEC and packed-cell volume (PCV) in all animals were 0.3 (+/-0.05), 0.26 (+/-0.04) and 0.42 (+/-0.05), respectively. The resistant group showed lower FEC and worm burdens than the susceptible group (P<0.05). There were no significant differences between groups regarding mean body weight, weight gain, PCV and total serum protein values (P>0.05). The resistant group showed higher total serum IgE levels (P<0.05) and higher mean eosinophil blood counts. However, the latter was statistically significant only 42 days after the beginning of the study. Nematodes Cooperia punctata and Haemonchus placei were predominant and the correlation between Cooperia and Haemonchus burdens was 0.64 (P<0.05), which indicated that animals presenting increased numbers of one of those genera probably had increased numbers of the other. The current study provides further evidence of IgE active role in nematode immunity and suggests that total serum IgE level might serve as an additional marker to select Nelore cattle that are responsive to H. placei and C. punctata infections.     

Adenosine deaminase activity in serum, erythrocytes and lymphocytes of rats infected with Leptospira icterohaemorrhagiae

Leptospirosis is a systemic disease of humans and domestic animals, mainly dogs, cattle and swine. The course of human leptospirosis varies from mild to severe fatal forms and the most severe form of human leptospirosis is principally caused by Leptospira interrogans serovar icterohaemorrhagiae (L. icterohaemorrhagiae). The enzyme adenosine deaminase (ADA) plays an important role in the production and differentiation of blood cells. The aim of this study was to evaluate the activity of ADA in serum, erythrocytes and lymphocytes of rats infected with L. icterohaemorrhagiae, as compared with non-infected rats. Twenty-four adult rats, divided into two uniform groups (A and B) were used for the enzymatic assays. The animals in Group B were inoculated intraperitoneally with 2×10(8) leptospires/rat, and the rodents in Group A (control) were not-inoculated. Blood collection was performed on days 5 and 15 post-infection (PI) and the blood used to assess the ADA activity. The infection by L.icterohaemorrhagiae altered erythrocyte count, hemoglobin concentration and hematocrit, causing a decrease in all these parameters on day 15 PI. Lymphocytes decreased significantly on day 15 PI, and ADA activity in serum was inhibited in infected rats on days 5 and 15 PI and its activity in erythrocytes were increased on day 5 PI. On day 5 PI, we found an increase in ADA activity in erythrocytes of infected rats. No correlation was observed between hematocrit and erythrocyte ADA activity on days 5 and 15 PI. The ADA activity was inhibited in rats infected on day 15 PI. A positive correlation (r(2)=60) was also observed between the number of lymphocytes and ADA activity in lymphocytes on day 15 PI (P<0.05). In conclusion, our results showed that the ADA activity is altered in serum, lymphocytes and erythrocytes in experimental infection by L.icterohaemorrhagiae in rats, concomitantly with hematological parameters.     

Laboratory and field investigations into the Theileria parva carrier-state in cattle in Zimbabwe.

The Theileria parva carrier-state in cattle on commercial farms on Zimbabwe was investigated using parasitological and serological methods. The proportion of cattle showing Theileria piroplasms on two farms, which had recent histories of disease outbreaks, were 64% (n = 106, total of heifers and weaned calves examined) and 71.5% (n = 60) while the proportion of T. parva antibodies for the same animals were 59% and 98.5%, respectively. On four farms where no cases of the disease occurred for over 10 years, the average proportion of animals showing piroplasms and antibodies were 55.4% (range 32-82, n = 223) and 73% (range 47-91, n = 223), respectively. However, on another three farms which had no history of theileriosis outbreaks these proportions were very low, being 11.4% (0-24, n = 157) for piroplasms and 12.2% (5-23, n = 157) for antibodies. The mean infection rate in unfed Rhipicephalus appendiculatus adults collected from farms with a high prevalence of cattle which were carriers of Theileria piroplasms during the tick activity season was 29% (range 12-60%) with 9.3 (range 2-18.7) mean infected acini per infected tick. The infectivity of different tick batches to susceptible cattle produced a wide spectrum of theileriosis reactions. Laboratory controlled experiments were carried out to study the persistence of T. parva (Boleni) piroplasms in cattle immunized with this strain as well as its infectivity for ticks and its subsequent transmissibility to cattle. Examination of the salivary glands of 15 batches of ticks collected from six immunized cattle on three different occasions over 18 months showed that none were infected with Theileria parasites. However, the infectivity of other ticks in the same batches to susceptible animals was demonstrated 6, 10 and 18 months after cattle had been immunized with Boleni stabilate.