Cotton-top tamarins (Saguinus oedipus oedipus) Hematologic reference values and hemopathologic responses.код для вставкиСкачать
American Journal of Primatology 5:231-239 (1983) Cotton-top Tamarins (Saguinus oedipus oedipus): Hematologic Reference Values and Hemopathologic Responses C.M. HAWKEY, M.G. HART, J.A. KNIGHT, A.K. FITZGERALD, ANI) D.M. JONES Department of Veterinary Science, Institute of Zoology, Zoological 5'ociet.y of London, London, England Hematologic reference values have been established for captive adult cottontop tamarins (Saguinus oedipus oedipus) by carrying out full blood counts and fibrinogen estimation on 43 clinically normal animals. Females were shown to have significantly lower hemoglobin levels, red cell counts and packed cell volumes, and higher reticulocyte counts than males. The reference values were used to identify abnormal changes in the blood of 13 clinical cases. Marked neutrophilia was found in animals with localized bacterial infections, and a degenerative left shift was recorded in an individual with streptococcal septicemia. Three cases of unexplained progressive muscle wasting showed Heinz body anemia and abnormal white cell changes. These hematologic responses have been compared where possible with those recorded in other species of Callithricidae. Key words: Cotton-top tamarin, Saguinus oedipus oedipus, bacterial infections, Heinz bodies, wasting marmoset syndrome, hematuria, myocardial degeneration INTROI~UCTION Clinical hematology provides a useful aid to differential diagnosis in man and domesticated animals and should also be of value i n other species including small primates. Unfortunately lack of normal reference values and of information about species variations in the response of the circulating blood to different disease processes can make the interpretation of blood counts on sick animals difficult. This has prevented the utilization of clinical hematology t o its full potential. Attempts are now being made to remedy this situation. Normal hematologic reference values have been reported for cotton-top tamarins (Saguinus oedipus oedipus) [Anderson et al, 1967; Burns et al, 19671, Panamanian tamarins (5'. geoffioyi) [Porter, 19701, white-lipped tamarins (S. nigricollis) [Anderson et al, 19671, red bellied tamarins (S. Labiatus) [Wadsworth et al, 1982; Hawkey et al, 19831, golden Received January 27, 1983; accepted June 21, 1983. Address reprint requests to Dr. C.M. Hawkey, Department of Veterinary Science, Institute of Zoology, Zoological Society of London, London NW1 4RY, England. CCJ 1983 Alan R. Liss, Jnc. 232 Hawkey et a1 lion tamarins (Leontopithecus rosalia) [Bush et al, 19821, and common marmosets (Callithrix jaccus) [Eccleston, 1977; Sanderson and Phillips, 1981; Hawkey et al, 1982; McNees et al, 19821. Hemopathologic responses have been investigated for three of these species: the golden lion tamarin [Bush et al, 19821; the red bellied tamarin [Hawkey et al, 19831; and the common marmoset [Hawkey et al, 19821. This study reports the results of a further study on cotton-top tamarins in which abnormalities in the blood count of 13 ill individuals were identified by comparison with reference values obtained from 43 normal animals and were related when possible to the clinical diagnosis and/or pathologic findings. In order to begin to define basic hemopathologic responses in marmosets and tamarins, the abnormal findings in bacterial infections and wasting syndromes have been compared between species when appropriate. MATERIALS AND METHODS Animals Blood samples were obtained from S. oedipus in the collection of the Zoological Society of London and from animals housed in the Institute of Zoology for reproductive studies. The group included 43 clinically normal adult ( > 1 year) animals and 13 ill individuals admitted to the Animal Hospital for diagnosis and treatment. Clinical normality was established by careful examination a t the time of sampling and from knowledge of previous and subsequent clinical histories. Blood Samples Using a plastic disposable syringe and disposable 23-gauge needles, 1.0 ml blood was collected from a femoral vein of each manually restrained or sedated animal. Sedation was by intramuscular injection of ketamine hydrochloride (Vetalar, Parke Davis) a t a dose rate of 25-30 m g k g body weight. No significant differences were found between hematologic values of conscious and sedated animals. The blood was placed immediately in commercially available plastic tubes containing 1.75 mg of the dipotassium salt of ethylenediamine tetraacetic acid (EDTA).Tests were carried out within four hours of obtaining the sample. Laboratory Methods These were based on techniques described for use on human blood [Dacie and Lewis, 19751 and have been detailed elsewhere [Hawkey et al, 19821. Fibrinogen was estimated as protein precipitated a t 56°C by the micromethod of Millar et a1 . Calculation of Reference Values Values for clinically normal adult males and females were compared by calculating the t statistic for two means. Where no significant sex difference was apparent, results on males and females were combined for calculation of means and standard deviations (SD). Values falling outside the range of & 2 x SD were considered to be abnormal [Hawkey et al, 19821. RESULTS Normal Blood Cell Morphology On blood films stained by the May-Grunwald-Giemsa method, red cells of normal animals usually showed slight anisocytosis, poikilocytosis, and polychromasia. In a few individuals, a small number of nucleated red cells (< 0.02 x 109m were found. In one clinically normal adult female, Heinz bodies were recorded in 5% of the red cells. Since there were no associated hematologic abnormalities and the individual remained healthy, it was included in the reference group. Cotton-top Tamarin Hematology 233 The neutrophils were regular, round cells (average diameter 13.0 pm) with welllobulated nuclei (three t o seven lobes, averaging five) and colorless cytoplasm containing numerous small pink or red granules. Eosinophils were similar in size with irregularly lobed nuclei and pale blue cytoplasm closely packed with small, spherical, strongly eosinophilic granules. The basophils were smaller cells (average diameter 12.1pm) with large, spherical, or oval purple granules completely filling the cytoplasm. Lymphocytes averaged 12.2 pm in diameter, with round nuclei and pale blue cytoplasm sometimes containing one or several small azurophilic granules. Monocytes were larger cells (average diameter 15.8 pm) with indented nuclei and slightly opaque, blue-grey, sometimes vacuolated cytoplasm. The platelets averaged 3.5 pm in size and contained distinctive basophilic granules. Microfilaria A small number of microfilaria, thought to be Dipetalonema sp., were found in the blood of eight of the clinically normal animals. There were no associated hematologic or clinical abnormalities. Reference Values Adult males had significantly higher hemoglobin (Hb), red cell counts (RBC), packed cell volume (PCV), mean cell hemoglobin (MCH) levels, and mean cell hemoglobin concentrations (MCHC), and lower reticulocyte counts than adult females. The relative (%) but not the absolute number of lymphocytes was significantly higher in females than in males. Females also had higher absolute eosinophil counts than males. Neither of these white cell differences was considered to be of biological significance. Sex differences and calculated reference values for adult males and females and for the group as a whole are shown in Table I. Clinical Cases Blood tests were carried out on 13 animals admitted to the Animal Hospital for diagnosis and treatment of disease (Table 11). Hematologic abnormalities in these cases were identified by comparison with the reference values given in Table I. One of the animals (case 8) was a juvenile for which adult reference may not be valid. However, the anemia and abnormalities in red cell and neutrophil morphology recorded in this case were considered unlikely to be related to an age effect. It has therefore been discussed with the adult group. For analysis of the hematologic abnormalities identified, the cases have been grouped according to clinical signs and response to treatment. Bacterial infections. Bacterial infection as the primary cause of illness was confirmed in three animals (cases 1, 2, 5) and suspected in another four (cases 3, 4, 5, 7) (Table 11).In four of these cases (1-4), the lesions were localized, the red cells were normal, but the total white cell counts (WBC) were raised. In cases 1,2, and 4 the leucocytosis was mainly a result of increased neutrophil numbers, although the neutrophil morphology was normal. Lymphocytosis was the only abnormal finding in case 3 and was also present in cases 1 and 2. Monocytosis, basophilia, raised fibrinogen, and thrombocytopenia were each recorded in a single animal (Table 11). Localized bacterial infection was also suggested by the clinical signs in cases 6 and 7. These two cases showed white cell changes similar to those in cases 1, 2 and 4, but additional minor red cell abnormalities were found. Case 6, although not anemic, showed Hb, RBC, and PCV levels below the reference ranges, probably due to chronic blood loss from the skin lesions. In case 7, the increased RBC could be attributed to hemoconcentration through excessive fluid loss from the gastrointestinal tract. 234 Hawkey et a1 TABLE 1. Hematologic Reference Values for Adult Cotton-Top, Tamarins ( S a p i n u s oedipus oedipus) Measurement No. and sex Hemoglobin (g/dl) 25, M 18, F 25, M 18, F 25, M 18, F 25, M 25, M 18, F 25, M 18, F 25, M 18, F 7M,5F 25 M, 18 F 25 M, 18 F 25 M, 18 F 25 M, 18 F 25, M 18, F 25 M, 18 F 25 M, 18 F 25, M 18,F 25 M, 18 F 25 M, 18 F 25 M, 18 F 15 M, 13 F 13 M, 11F Red cell count ( X lO''/L) Packed cell volume (LA) Mean cell volume (fl) Mean cell hemoglobin (pg) Mean cell hemoglobin concentration (gidl) Reticulocytes (%f ESR (mm in 1 hr) White cell count ( x lo9&) Neutrophils ( x lo9/%) Lymphocytes ( x lo9&) Monocytes ( x 109/L) Eosinophils ( X lo9&) Basophils ( x 109/L) Neutrophils (%) Lymphocytes (Q) Monocytes (%,) Eosinophils (%) Basophils (%) Platelets ( x 1 0 ' 1 ~ ) Fibrinogen (gidl) Average 17,5"** 16,0**" 6.7* 6.3" 0.52"* * 0.48*** 76.8 26.3" 25.4* 34.0* 33.3* 3.2"" 5.5"* 0 7.7 5.19 2.36 0.11 0.03" 0.11" 0.07 65.6 26.0* 35.0" 1.3 1.0 0.8 398 3.9 SD T 1.4 i 1.4 k0.6 i0.5 + 0.03 k0.03 +3.6 k1.3 11.6 k 1.3 11.0 k 1.3 13.2 i2.0 +1.84 f0.90 k0.15 10.06 k0.13 k0.08 k7.7 k11 10 k 1.5 k1.3 k 1.1 ill1 10.7 * Range 15.5 - 20.1 13.3 - 18.8 5.7 - 7.7 5.4 - 7.2 0.5 - 0.58 0.3 - 0.53 70.0 - 83.2 23.8 - 28.7 22.2 - 28.1 31.9 - 36.8 31.8 - 35.0 0.7 - 6.2 0.4 - 11.5 0 4.2 - 11.1 2.10- 8.68 0.91- 4.28 0 - 0.34 0 - 0.30 0 - 0.30 0 - 0.26 53 - 78 10 - 56 15 - 55 0 - 5 0 - 0 0 - 4 195 -607 2.5 - 5.2 Abbruuiatcons: ESR, erythrocyte sedimentation rate [Wintrobe, 19671. *P < 0.05, **P < 0.01, ***:P< 0.005. In case 5, a n animal which was tested immediately before it was euthanized for humane reasons, the WBC and neutrophil counts were within normal limits, but the neutrophils showed a left shift, and the fibrinogen level was raised. By analogy with C. jacchus [Hawkey et al, 19821 the results suggested an overwhelming bacterial infection, and this diagnosis was confirmed by the postmortem finding of streptococcal septicemia. The possible significance of the presence of Heinz bodies in a small number of red cells in this animal is discussed below. Generalized wasting. Three animals (cases 8-10) were studied in which the main abnormal signs were progressive muscle wasting and loss of condition (Table 11). These cases were of particular interest because, as well as having similar presenting signs, they also showed several features in common with each other and with S. labiatus and C. jacchus which may have been suffering from wasting marmoset syndrome (WMS) [Shimwell et al, 1979; Hawkey et al, 1982, 1983). All three cases showed reduced Hb, RBC, and PCV levels, red cells containing Heinz bodies, and neutrophilia with a left shift. All three animals died or were euthanized Cotton-top Tamarin Hematology 235 in extremis and in two (cases 8 and 9) the cause of the wasting illness was not found. The third (case 8 ) showed postmortem evidence of peritonitis but this was considered unlikely to have been the cause of the progressive muscle wasting and loss of condition. The hematologic findings in these cases are compared with those on S. labiatus and C. jacchus with generalized signs of wasting in Table 111. Miscellaneous clinical cases. An adult female (case 11)in which intermittent hematuria had been noticed for 3 weeks following a cesarian section for removal of a dead fetus showed red cell abnormalities consistent with compensated chronic blood loss. Blood coagulation screening tests were normal. Exploratory laparotomy revealed enlarged blood vessels on the wall of the bladder and adhesions between the bladder and the wall of the peritoneal cavity. The neutrophilia and monocytosis seen in this case were not explicable in terms of a concurrent infection. There was no further hematuria after surgical removal of the adhesions and recovery was uneventful. A second animal (case 12) in which hematuria was reported showed a normal blood count and in this case, no abnormalities were detected a t laparotomy. A male (case 13)which had been successfully treated for severe osteodystrophy five years previously and which was tested after sudden collapse showed lymphopenia, neutrophils with a left shift, and a significant number of circulating nucleated red cells. This animal was euthanized after sampling. A t postmortem examination there was a large amount of pericardial fat and the myocardium appeared congested. Histologic examination showed evidence of moderate myocardial fibre degeneration; this finding was substantiated by acid fuchsin staining and was considered to be a contributory cause of morbidity. DISCUSSION The normal adult S. labiatus tested in this survey had lower neutrophil counts than those studied by Burns et a1  but otherwise the reference values were generally similar to those reported for other Callitrichid species [Anderson et al, 1967; Porter, 1970; Eccleston, 1977; Sanderson and Phillips, 1981; Bush et al, 1982; Hawkey et al, 1982; Wadsworth et al, 19821. The sex differences in Hb, RBC, and PCV levels are similar to that found in L. rosalia and some other species of primates [Bush et al, 19821 including man. The validity of the reference values is illustrated by the fact that they have provided the basis for identification of abnormalities in the blood of all but one of the clinical cases examined. The single case in which the blood count was normal was a n animal with transient hematuria in which an exploratory laparotomy also failed to show any abnormalities (case 12). As well as the need for valid reference values, a second prerequisite for the interpretation of blood counts on ill animals is a n understanding of the range and specificity of hemopathologic responses likely to occur. This information is difficult to obtain because detailed case histories including hematologic data are rarely reported. However, the present study of S. oedipus, together with recent surveys relating blood findings to diagnosis in C. jacchus, L. rosalia, and S. labiatus provides material for a preliminary comparison of hemopathologic responses in marmosets and tamarins. Although it is often difficult to find exact clinical parallels between the species, some apparent similarities and differences are worthy of note. The group of S. oedipus tested included several animals with localized bacterial infections in which marked neutrophilia was the most significant finding. Neutrophi1 counts of up to 21 x 109A have been recorded in these individuals, indicating that the quantitative leucocyte response to infection in S. oedipus can be relatively large and that white cell counts can be useful in the differential diagnosis of infection in this species. A similar degree of neutrophilia has been reported in S. labiatus with infectious conditions [Hawkey et al, 19831 whereas in C. jacchus and Clinical observations Case no. WBC 21.7t, neutros 12.81, lymphs 7.8t, monos 0.781 WBC 29.3t, neutros 19.6t, lymphs 6.2T, basos 0.3t (fibrinogen ND) WBC 13.7t, lymphs 8.4t WBC 32.3t, neutros 18.7t, lymphs 12.61, platelets 11OL, fibrinogen 6.41 Neutros left shift, fibrinogen 5.21, occasional Heinz body WBC 22.5T, neutros 16.21, lymphs 5.4t, monos 0.5t, Hb 14.61, PCV 0.441, MCV 65.51, MCH 21.71 (fibrinogen ND) WBC 21.71, neutros 16.91, monos 0.41, RBC 8 . l t , MCV 65.81, MCH 21.71, (fibrinogen ND) WBC 25.77, neutros 21.9t, left shift, RBC 3.01, Hb 7.31, PCV 0.231, target cells +, Heinz bodies 2% of RBC, retics 9.81, platelets 6501 Recurrent face abscess Abscess, forelimb Abscess, face Abscess, neck Collapse Infected dermatitis, self-inflicted exacerbation Diarrhea 9/12, proteinuria Diarrhea, muscle wasting, loss of condition, alopecia of tail region Ad, F Ad, M Ad, M Ad, M Ad, M 14 Y, M 11-12 y, M Hematologic abnormalities Ad, M Age and sex Cases TABLE 11. S. oedipus-Clinical Outcome Euthanasia i n extremis. Peritonitis. Mesenteric lymph nodes enlarged and melanotic. No pathogens isolated from feces. Recovered without treatment. Euthanasia. Streptococcal septicemia. Fusion of mandibular joint. Not known Staphylococcus aureus and Candida parupsilosis isolated from lesion. Recovered after antibiotic treatment. Klebsiella pneumoniae isolated from lesion. Recovered after antibiotic treatment. No organisms isolated. Recovered after antibiotic treatment. No organisms isolated. Recovered after antibiotic treatment. % E Y F8 Q, N W Transient hematuria Collapse Ad, M 3y,F Ad, M >10y,M 10 11 12 13 Neutros left shift, lymphs 0.41. nucleated RBC 0.3T WBC 27.31, neutros 11.71, lymphs 15.0t, RBC 5.41, Hb 13.61, PCV 0.441, MCHC 30.91, Heinz bodies 2.8% of RBC WBC 5 6 . l t , neutros 40.47, left shift, lymphs 15.7t, RBC 4.81, Hb 12.21,PCV 0.391, MCHC 31.31, retics 8.8t, Heinz bodies 10%of RBC WBC 16.5t, neutros 11.7t, monos 0.81, RBC 5.21, Hb 12.91, PCV 0.381, MCHC 31.61, retic 11.3t, nucleated RBC 0.8t None (fibrinogen ND) WBC 22.9t, neutros 15.01, left shift, lymphs 8.0t, RBC 5.41, Hb 11.81, PCV 0.361, occasional Heinz body, fibrinogen 7.27, platelets 682T WBC 3.51, neutros 1.81, RBC 4.21, Hb 8.81,retics 10.4T Exploratory laparotomy. No abnormalities detected. Euthanasia. Myocardial failure, senilitv. Exploratory laparotomy. Surgical removal of adhesions. Recovered. Died next day. Generalised muscle wasting. Lymph nodes enlarged, adrenals congested. Cause of death not apparent. Euthanasia in extremis. Minimal hemorrhagic bladder necrosis. Cause of morbidity not apparent. Treated with antibiotics, multivitamins. Condition improved after antibiotic treatment. Abbreuiations: basos, basophils ( x lo9 L); Hb, hemoglobin (g/dl); lymphs, 1 mphocytes ( x lo9 L);MCH, mean cell volume (fl); MCHC, mean cell hemoglobin concentration (gidl); MCV, mean cell volume (fl); monos, monocytes ( X 10B L); ND, not done; neutros, neutrophils ( X lo9 L); PCV, packed cell volume (LLL); RBC, red cell count ( x 10l2L); WBC, white cell count ( X lo9 L); t values above normal; 1 values below normal. Hematuria, 4 wec--s. Previous cesarian section. Weight loss. Collapse 6 weeks later. Loss of condition Collause. 2 weeks later. Hematuria. Collapse, loss of condition, diarrhea. Twin of case 8. 1 Y, M 9 238 Hawkey et a1 TABLE 111. Hematologic Abnormalities in S. oedipus, S. labiatus, and C. jacchzts With Progressive Wasting No. tested No. with Anemia Heinz bodies Reticulocytosis Neutrophilia Neutropenia Left shift Lymphocytosis Lymphopenia Thrombocytosis Thrombocytopenia Raised fibrinogen No. deadb S. oedipus S. labiatus C. jacchus 3 2 14 3 3 2 1 1 0 0 1 0 2 1 1 2 2 6 14 5 2 3 1 3 2 0 2 0 1 3 4 1 6 3 1 8" 0" 4a 9 "Not all animals tested. bDied or euthanased in extremis. L. rosalia the neutrophil response to infection is apparently qualitative rather than quantitative and has been described in terms of a n increased number of band forms in L. rosalia [Bush et al, 19821 and as a shift to the left in C. jacchus IHawkey et al, 19821. A degenerative shift to the left was found in a n S. oedipus with streptococcal septicemia (case 5 ) and provided a situation analogous to that described in C. jacchus with overwhelming infections [Hawkey et al, 19821. Monocytosis and increased fibrinogen levels have been associated with bacterial infections in all four species and high platelet counts appear to be a particularly characteristic response in C. jacchus. The occurrence of unexplained weight loss and muscle wasting in three of the S. oedipus studied suggests a parallel with the condition known as WMS described in C. jacchus [Shimwell et al, 1979; Hawkey et al, 19821 and other related species [King, 1976; Morin and Spiegler, 1982; Hawkey et al, 19831. Although WMS is considered to be a n important cause of death among captive marmosets, the clinical signs of the disease have not yet been defined satisfactorily and the etiology is not known. Thus, hematologic pointers could be of great value in elucidating this condition. Our comparisons of blood counts on the three S. oedipus with signs of wasting with those on S. labiatus and C. jacchus with similar clinical signs confirms the claim by Shimwell et a1 [19791 that Heinz body anemia is a common finding in WMS. However, in the present survey, Heinz bodies were found in one healthy animal and in one ill animal (case 5) in which wasting was not apparent and have also been reported in normal C. jacchus [Sanderson and Phillips, 1981; Hawkey et al, 19821. Their presence is therefore apparently not pathognomic for WMS. The alternative possibility that a shared feature of marmoset and tamarin red cells renders them particularly susceptible to Heinz body formation and that conditions triggering the mechanism occur in WMS is currently under investigation. The white cell changes associated with wasting in the three marmoset and tamarin species show no consistent pattern. However, the relative frequency of both quantitative and qualitative neutrophil abnormalities, high fibrinogen levels, and increased platelet counts suggests that infection may be involved, either as a triggering factor or as a terminal event. Cotton-top Tamarin Hematology 239 Taken as a whole, t h e findings reported in this study confirm that normal blood values in closely related species are similar but that interspecies differences in hemopathologic responses occur. Further analysis of blood findings on carefully documented clinical cases is needed to clarify these differences. CONCLUSIONS 1.Hematologic findings on 43 clinically normal adult Saguinus oedipus oedipus have provided reference values for the identification of hemopathologic changes in 13 ill individuals. 2. Adult females normally have lower Hb levels, RBC, and PCV and higher reticulocyte counts than adult males. 3. Marked neutrophilia was characteristic of localized bacterial infection. A case of streptococcal septicemia showed a degenerative left shift of the neutrophils. 4. Three animals with unexplained progressive muscle wasting showed Heinz body anemia, neutrophilia with a left shift, and several other white cell and platelet abnormalities. The hematologic findings in these cases were generally similar to those recorded in S. labiatus and Callithrix jacchus which may have had wasting marmoset syndrome. ACKNOWLEDGMENTS We wish to thank Mr. S. Pugsley and Mr. R. Parsons for postmortem and microbiological studies and Mrs. B. Murrill and her staff for day to day care of the animals. REFERENCES Anderson, E.T.; Lewis, J.F.; Passovoy, M.; Trobaugh, F.E. Marmosets as laboratory animals. 11: The hematology of laboratory kept marmosets. LABORATORY ANIMAL CARE 17:30-39,1967. Burns, K.F.; Ferguson, F.G.; Hampton, S.H.; Compendium of normal blood values for baboons, chimpanzees and marmosets. AMERICAN JOURNAL OF CLINICAL PATHOLOGY 48:484-494,1967. 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