Elective ovariohysterectomy or castration can proceed in shelter dogs despite mild to moderate presurgical leukocytosis

Poyu Lai Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS

Search for other papers by Poyu Lai in
Current site
Google Scholar
PubMed
Close
 BS
,
Kate S. KuKanich Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS

Search for other papers by Kate S. KuKanich in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
, and
Nora L. Springer Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS

Search for other papers by Nora L. Springer in
Current site
Google Scholar
PubMed
Close
 DVM, PhD

Click on author name to view affiliation information

Abstract

OBJECTIVE

To determine whether shelter dogs presenting for elective ovariohysterectomy or castration have leukocytosis, whether leukocytes are associated with age and infection, and whether leukocytosis precludes progression to surgery.

ANIMALS

138 dogs (from 13 regional shelters) presented for ovariohysterectomy or castration between October 7 and December 6, 2019.

PROCEDURES

For this prospective study, each dog underwent presurgical physical examination, CBC, and tests for Dirofilaria immitis antigen and Anaplasma phagocytophilum, Borrelia burgdorferi, and Ehrlichia canis antibodies, with additional tests performed as needed. Dogs were aged by dentition as juvenile (< 3 or ≥ 3 to ≤ 6 months) or adult (> 6 months). Leukogram results were compared across age groups with recognized infections and parasitism and with dogs’ progression to surgery.

RESULTS

There were 34 dogs < 3 months old, 22 dogs ≥ 3 to ≤ 6 months old, and 82 > 6 months old. Sixty-three of 138 (45.6%) dogs had leukocytosis (median, 16,500 cells/µL; range, 13,700 to 28,300 cells/µL). Dogs < 3 months of age had higher median leukocyte and lymphocyte counts (14,550 cells/µL and 3,700 cells/µL, respectively) than dogs > 6 months of age (12,500 cells/µL and 2,400 cells/µL, respectively). Only 1 dog had a stress leukogram. Forty-seven dogs had recognized infection, but there was no association with leukocytosis. Surgery proceeded successfully for all dogs with leukocytosis.

CLINICAL RELEVANCE

Mild to moderate leukocytosis is common before elective surgery in shelter dogs, but surgery can proceed safely. A CBC should be reserved for ill-appearing dogs rather than as a screening test, and age-specific reference intervals should be considered.

Abstract

OBJECTIVE

To determine whether shelter dogs presenting for elective ovariohysterectomy or castration have leukocytosis, whether leukocytes are associated with age and infection, and whether leukocytosis precludes progression to surgery.

ANIMALS

138 dogs (from 13 regional shelters) presented for ovariohysterectomy or castration between October 7 and December 6, 2019.

PROCEDURES

For this prospective study, each dog underwent presurgical physical examination, CBC, and tests for Dirofilaria immitis antigen and Anaplasma phagocytophilum, Borrelia burgdorferi, and Ehrlichia canis antibodies, with additional tests performed as needed. Dogs were aged by dentition as juvenile (< 3 or ≥ 3 to ≤ 6 months) or adult (> 6 months). Leukogram results were compared across age groups with recognized infections and parasitism and with dogs’ progression to surgery.

RESULTS

There were 34 dogs < 3 months old, 22 dogs ≥ 3 to ≤ 6 months old, and 82 > 6 months old. Sixty-three of 138 (45.6%) dogs had leukocytosis (median, 16,500 cells/µL; range, 13,700 to 28,300 cells/µL). Dogs < 3 months of age had higher median leukocyte and lymphocyte counts (14,550 cells/µL and 3,700 cells/µL, respectively) than dogs > 6 months of age (12,500 cells/µL and 2,400 cells/µL, respectively). Only 1 dog had a stress leukogram. Forty-seven dogs had recognized infection, but there was no association with leukocytosis. Surgery proceeded successfully for all dogs with leukocytosis.

CLINICAL RELEVANCE

Mild to moderate leukocytosis is common before elective surgery in shelter dogs, but surgery can proceed safely. A CBC should be reserved for ill-appearing dogs rather than as a screening test, and age-specific reference intervals should be considered.

Introduction

Veterinarians conduct preanesthetic patient evaluations prior to surgery in dogs to determine if additional diagnostic testing or anesthetic protocol adjustments are needed to optimize safety. In addition to evaluating the patient’s history, current medications, and physical examination, the American Animal Hospital Association’s Anesthesia and Monitoring Guidelines suggest that a minimum database including a CBC might be warranted for some patients.1 Anemia is listed as an anesthetic risk factor in veterinary medicine; thus, a PCV is often performed prior to elective and nonelective surgeries.1 However, the value of the leukogram in determining anesthetic risk and altering candidacy for surgery is less clear. In human health care, presurgical laboratory work is not recommended for relatively healthy general surgical patients, such as patients in the American Society of Anesthesiologists Grade 1 undergoing low to moderate risk surgery, as results have not corresponded with changes in protocol, complications, or outcome.2,3 Veterinary studies assessing utility of preanesthetic laboratory testing have found mixed results. In a study4 of 1,537 dogs, laboratory changes were of little clinical relevance and did not prompt major changes to anesthetic technique. However, in a separate study,5 veterinary anesthesiologists reviewing 100 canine medical records would alter perioperative management on the basis of laboratory screening results in 79% of cases, yet there was weak agreement between anesthesiologists.

Dogs from a shelter presenting for routine elective ovariohysterectomy (OHE) or castration often have limited medical history available and might have unknown comorbidities or subclinical infections that alter their anesthetic risk even if they appear outwardly healthy. This population of dogs might also have increased stress due to living in a shelter environment or recent rehoming,6 which can also increase their risk of infection. It would be helpful to know if the value and cost of a full CBC prior to an elective surgery is justified for shelters or new pet owners, compared with a simple PCV. Leukocyte counts can be affected by age, stress, medications, vaccines, infection, and inflammation, among other factors.79 One study6 found that, 1 day after entering a shelter, 92 healthy dogs > 6 months of age had significantly higher total leukocyte and neutrophil counts than did a control group of 15 privately owned dogs. After 1 month of living in a shelter, neutrophil count decreases and lymphocyte count increases in dogs, which might suggest a decrease in stress and improvement in welfare.10 Leukogram findings in dogs from a shelter setting presenting to a veterinarian for elective OHE or castration have not been reported.

In healthy research Beagles, it is well described that total leukocyte count varies with age as puppies develop into adults. Compared to a laboratory reference interval (RI) for leukocyte counts in adult dogs (13,951 cells/µL), newborn healthy Beagle puppies have a leukocyte count of 16,493 to 16,800 cells/µL, and this value decreases by 1 month of age (13,075 to 13,900 cells/µL), then increases by 3 months of age (17,051 cells/µL), and then gradually declines to the normal adult value.11,12 Similar leukogram RIs have not been determined for a mixed population of juvenile dogs that appear healthy but might have subclinical disease. As elective OHE and castration can occur in dogs from < 3 months of age until adult,13 knowing leukogram age differences in this population of dogs would be valuable to allow for improved interpretation of health and anesthetic risk.

This study aimed to determine the value of the leukogram as a preanesthetic screening test for elective OHE or castration in juvenile and adult dogs from a shelter setting. Specifically, we aimed to determine whether shelter dogs presenting for elective OHE or castration have higher leukocyte counts than RIs and to describe the leukogram patterns seen (acute inflammatory, chronic inflammatory, steroid leukocytosis, or physiologic leukocytosis). Further, we aimed to determine whether leukocyte counts were associated with age or typical infections seen in shelter dogs and whether leukocytosis precludes progression to elective surgery. It was hypothesized that leukocytosis would be common in shelter dogs presenting for elective OHE or castration due to increased stress and that juvenile dogs would have higher leukocyte counts than adults, consistent with data from healthy juvenile research Beagles. It was also hypothesized that these leukogram changes would not be clinically relevant or change whether dogs would be able to safely proceed with elective surgery.

Materials and Methods

Animals

For this prospective study, dogs were enrolled from regional shelters that were presented to the Kansas State University College of Veterinary Medicine for elective OHE and castration by veterinary students in the Veterinary Surgery course from October 7 to December 6, 2019. Prior to presentation, dogs were evaluated by a shelter veterinarian or shelter staff (when no veterinarian available) and determined to be healthy and considered good candidates for elective OHE or castration. A medical history for each dog was provided, and data collected included date and type of vaccinations received, infectious disease testing, and prior medications. Informed consent was provided by participating shelters before enrollment for physical examination, phlebotomy, fecal, and radiographic examinations, general anesthesia, and surgery. The study protocols were reviewed and approved by the university’s Institutional Animal Care and Use Committee. Although all dogs were determined to be healthy by the shelter prior to presentation, some dogs enrolled in this study were diagnosed with infectious and inflammatory conditions during their presurgical physical examination and diagnostic testing at Kansas State University, as described below.

Patient assessments

Physical examination—Each dog received a complete physical examination by a third-year veterinary student and faculty veterinarian on the day of arrival at Kansas State University. Each dog’s age was estimated by the research team on the basis of dental eruption status. Dogs with no adult incisors erupted were estimated to be < 3 months of age, dogs with ≥ 1 erupted adult incisor but ≤ 3 erupted adult canine teeth were estimated to be ≥ 3 to ≤ 6 months of age, and dogs with complete eruption of all 4 adult canine teeth were estimated to be > 6 months of age.14 Dogs ≤ 6 months of age were considered to be juvenile, while dogs > 6 months of age were considered to be adults.

Hematologic assessments—Each dog underwent jugular or lateral saphenous vein phlebotomy with a 20- to 23-gauge needle attached to a 3- to 5-mL nonheparinized syringe to collect 2 mL of blood, which was then transferred to a plastic Vacutainer EDTA tube. A commercially available ELISA test (Snap 4Dx; Idexx Laboratories Inc) to detect antibodies for Anaplasma phagocytophilum, Borrelia burgdorferi, and Ehrlichia canis, and Dirofilaria immitis antigen was performed for each dog. Whole blood samples in Vacutainer EDTA tubes were submitted to the Kansas State Veterinary Diagnostic Laboratory for CBC with a commercial analyzer (ADVIA 2120i; Siemens Medical Solutions). Total leukocyte count from the hematology analyzer as well as counts of segmented neutrophils, nonsegmented neutrophils, lymphocytes, monocytes, eosinophils, and basophils from a 100-cell differential count, performed by medical technologist review of blood smears were recorded. White blood cell morphology and platelet estimate from blood smear evaluation were also recorded. For the purpose of this study, leukogram patterns were defined as previously described.7 Erythrogram parameters for these dogs have been reported previously.15

Fecal tests—Fecal flotations were performed by students for dogs with soft feces or diarrhea. A commercially available parvovirus antigen test (SNAP Parvo; Idexx Laboratories Inc) was performed on any dog with lethargy, vomiting, bloody diarrhea, or leukopenia alone or in combination.

Treatment decisions

Dogs with no obvious evidence of anesthetic or surgical contraindications based on physical and other diagnostic examinations underwent elective OHE or castration performed by third-year veterinary students under close supervision by faculty anesthesiologists and surgeons. Postoperatively, dogs received appropriate analgesia, were monitored closely, and were returned to their shelters 3 days after surgery.

Statistical analysis

Descriptive statistics were used to summarize results for demographic information, diagnostic testing, and infectious or inflammatory disease conditions. The Shapiro-Wilk test was used to test whether the leukocyte, neutrophil, monocyte, lymphocyte, eosinophil, or basophil counts had normal distributions within each age group. The leukogram data within age groups were not all normally distributed; thus, the nonparametric Kruskal-Wallis 1-way ANOVA test with Dunn pairwise comparisons was used to compare median leukocyte, neutrophil, lymphocyte, monocyte, eosinophil, and basophil counts across age groups. The χ2 test was used to compare proportions of dogs with leukogram results that were above, within, or below the RIs across age groups. For eosinophil and basophil counts, the Freeman-Halton extension of the Fisher exact probability test was used to compare proportions of dogs above or within the RIs across age groups because it was a 2 X 3 contingency table and over 20% of the expected values in the table were less than 5. The Shapiro-Wilk test was performed to test whether dogs of either sex had normal distribution of data within each age group (ie, leukocyte count in male dogs < 3 months old). The leukogram data across sexes within age groups included both normally distributed data and nonnormally distributed data. A Mann-Whitney rank sum test (nonnormally distributed) or t test (normally distributed) was used to compare median or mean leukogram results across sexes within each age group, respectively. The χ2 test was also used to compare the proportions of dogs with documented infections or parasites with the proportion of dogs having leukocytosis. Significance was set at P ≤ 0.05; however, a Bonferroni adjustment was made to the P value to account for multiple comparisons. Commercial software programs (SigmaPlot version 12.5; Systat Software Inc; and Prism version 7.03; GraphPad Software) were used for statistical analysis and figure creation.

Results

Animals

There were 138 dogs enrolled from 13 regional shelters. Based on the age estimation from dental eruption status, 34 dogs were < 3 months of age (18 males and 16 females), 22 dogs were ≥ 3 to ≤ 6 months of age (8 males and 14 females), and 82 dogs were > 6 months of age (35 males and 47 females). During surgery at the Kansas State University, 4 of the 77 females (all adults) were found to have already been spayed. Dogs presented were well distributed among the 13 shelters: dogs that were < 3 months of age were presented from 6 shelters, dogs that were ≥ 3 to ≤ 6 months of age were presented from 8 shelters, and dogs that were > 6 months of age were presented from 12 shelters.

Vaccine history was provided for 114 of the 138 (82.6%) dogs, including rabies (63 dogs), combination vaccination for distemper, adenovirus, parainfluenza, and parvovirus (108 dogs), and Bordetella (71 dogs) but was incomplete and variable. No dog had a record of steroid or antimicrobial treatment prior to presentation. One hundred twenty-eight out of 138 (92.8%) dogs had received anthelmintic or flea prevention treatment prior to presentation (32 dogs < 3 months old, 19 dogs ≥ 3 to ≤ 6 months old, and 77 dogs > 6 months old). Among those 128 dogs, 51 dogs were given anthelmintic medication within 2 weeks prior to presentation (12 dogs < 3 months old, 8 dogs ≥ 3 to ≤ 6 months old, and 31 dogs > 6 months old). Sixty-five of 128 dogs were treated with flea prevention within 2 weeks prior to presentation (16 dogs < 3 months old, 13 dogs ≥ 3 to ≤ 6 months old, and 36 dogs > 6 months). Product and doses for anthelmintic and flea prevention varied.

Leukogram data

Complete leukogram data were available for all enrolled dogs. Sixty-three of 138 (45.6%) dogs had a leukocytosis (median, 16,500 cells/µL; range, 13,700 to 28,300 cells/µL), compared to the laboratory’s RI (4,300 to 13,600 cells/µL). No dog had leukopenia. Dogs < 3 months of age had a higher (P = 0.014) median leukocyte count (14,550 cells/µL) than dogs > 6 months of age (12,500 cells/µL; Figure 1). Similarly, there was a higher (P = 0.002) proportion of dogs < 3 months of age (24/34 [70.6%]) with leukocyte counts above the adult laboratory RI than dogs > 6 months of age (30/82 [36.6%]; Table 1).

Figure 1
Figure 1
Figure 1

Individual-value plots of leukocyte (A) and lymphocyte (B) count results for 138 shelter dogs, grouped by age (< 3 months, ≥ 3 to ≤ 6 months, or > 6 months), that were presented for routine ovariohysterectomy or castration between October 7 and December 6, 2019. Asterisks signify significant (P < 0.05) differences in median leukocyte count or lymphocyte count between age groups. For each plot, each circle represents the result for 1 dog, the longest horizontal line on the vertical bar represents the median, and the lower and upper horizontal lines on the vertical bar represent the limits of the interquartile (25th to 75th percentiles) range.

Citation: Journal of the American Veterinary Medical Association 260, 7; 10.2460/javma.21.10.0455

Table 1

Results of χ9 test to compare proportions of leukogram results that were below, within, or above laboratory reference intervals (RIs) for 138 shelter dogs that were presented for routine ovariohysterectomy or castration between October 7 and December 6, 2019, stratified by age groups (< 3 months of age, ≥ 3 to ≤ 6 months of age, and > 6 months of age).

< 3 months of age (n = 34) ≥ 3 to ≤ 6 months of age (n = 22) > 6 months of age (n = 82)
No. (%) of dogs No. (%) of dogs No. (%) of dogs
Cell type RI for adult dogs Median (range) With results below RI With results within RI With results above RI Median (range) With results below RI With results within RI With results above RI Median (range) With results below RI With results within RI With results above RI χ2 P value
Total Leukocytes (103 cells/µL) 4.3–13.6 14.55 (6.1–21.3) 0 (0) 10 (29.4) 24 (70.6) 13.2 (9.1–28.3) 0 (0) 13 (59.1) 9 (40.9) 12.5 (6.1–28.3) 0 (0) 52 (63.4) 30 (36.6) 11.4 0.003
Segmented Neutrophils (103 cells/µL) 2.5–9.3 9.35 (3.7– 17.2) 0 (0) 17 (50.0) 17 (50.0) 8.35 (5.0–23.5) 0 (0) 15 (68.2) 7 (31.8) 8.4 (3.9–18.8) 0 (0) 51 (62.2) 31 (37.8) 2.2 0.333
Lymphocytes (103 cells/µL) 0.8–4.3 3.7 (1.0–7.5) 0 (0) 20 (58.8) 14 (41.2) 3.4 (0.3–8.5) 1 (4.5) 17 (77.3) 4 (18.2) 2.4 (0.1–7.6) 5 (6.1) 67 (81.7) 10 (12.2) 13.7 0.008
Monocytes (103 cells/µL) 0–3.3 0.8 (0–2.1) 1 (2.9) 22 (64.7) 11 (32.4) 0.7 (0.2–1.9) 0 (0) 16 (72.7) 6 (27.3) 0.7 (0–3.3) 2 (2.4) 65 (79.3) 15 (18.3) 3.5 0.473
Eosinophils (103 cells/µL) 0–1.5 0.4 (0–1.4) 0 (0) 34 (100) 0 (0) 0.3 (0–2.6) 0 (0) 20 (90.9) 2 (9.1) 0.4 (0–6.0) 0 (0) 74 (90.2) 8 (9.8) 0.157
Basophils (103 cells/µL) 0–0.1 0 (0–0.2) 0 (0) 33 (97.1) 1 (2.9) 0 (0–0.2) 0 (0) 21 (95.5) 1 (4.5) 0 (0–0.3) 0 (0) 76 (92.7) 6 (7.3) 0.873

— = Test not performed (the Freeman-Halton extension of the Fisher exact probability test was performed rather than the χ2 test).

Fifty-five of 138 (39.9%) dogs had a neutrophilia (median, 11,600 cells/µL; range, 9,400 to 23,500 cells/µL), compared to the laboratory’s adult RI (2,500 to 9,300 cells/µL). No dogs had neutropenia. There was no association of median neutrophil count (9,350 cells/µL for dogs < 3 months of age, 8,350 cells/µL for dogs ≥ 3 to ≤ 6 months of age, and 8,400 cells/µL for dogs > 6 months of age) with age (P = 0.343). Six dogs had nonsegmented neutrophil counts higher than the RI (0 to 100 cells/µL), including 3 dogs < 3 months (200 cells/µL each), 1 dog ≥ 3 to ≤ 6 months (200 cells/µL), and 2 dogs > 6 months (200 cells/µL and 500 cells/µL). No dog had toxic change of neutrophils noted.

Most dogs (104/138 [75.4%]) had a lymphocyte count within RI (800 to 4,300 cells/µL). Lymphopenia was uncommon (6/138 [4.3%]), with a median of 650 cells/µL (range, 100 to 700 cells/µL). The median lymphocyte count was higher (P < 0.001) in dogs < 3 months of age (3,700 cells/µL) compared with dogs > 6 months of age (2,400 cells/µL), and higher (P < 0.01) in dogs ≥ 3 to ≤ 6 months old (3,400 cells/µL) compared with dogs > 6 months of age (Figure 1). Similarly, a higher (P = 0.008) proportion of dogs < 3 months of age (14/34 [41.2%]) had lymphocyte counts above the RI than did dogs ≥ 3 to ≤ 6 months of age (4/22 [18.2%]) or dogs > 6 months of age (10/82 [12.2%]; Table 1). On blood smear evaluation, 19 of the 138 (13.8%) dogs (2 dogs < 3 months old, 2 dogs ≥ 3 to ≤ 6 months old, and 15 dogs > 6 months old) had rare reactive lymphocytes, 35 (25.3%) dogs (11 dogs < 3 months old, 6 dogs ≥ 3 to ≤ 6 months old, and 19 dogs > 6 months old) had occasional reactive lymphocytes, and 25 (18.1%) dogs (10 dogs < 3 months old, 5 dogs ≥ 3 to ≤ 6 months old, and 10 dogs > 6 months old) had mild reactive lymphocytes.

Most dogs (103/138 [74.6%]) had monocyte counts within RI (0 to 900 cells/µL). Monocytosis was uncommon (32/138 [23.2%]), with a median of 1,200 cells/µL (range, 1,000 to 3,300 cells/µL). There was no difference in median monocyte count between age groups (P = 0.142). Ten dogs had eosinophilia (RI, 0 to 1,500 cells/µL) including 2 dogs ≥ 3 to ≤ 6 months old (1,600 cells/µL and 2,600 cells/µL), and 8 dogs > 6 months old (median, 2,300 cells/µL; range, 1,600 to 6,000 cells/µL). There was no difference in median eosinophil count between age groups (P = 0.787). Eight dogs had basophil counts above the RI (0 to 100 cells/µL), with a median of 200 cells/µL (range, 200 to 300 cells/µL), with no difference in median basophil counts between age groups (P = 0.289).

Results of normality testing and comparison of leukogram cell types by sex of dogs were compiled (Table 2). When dogs were grouped by age, there were no significant differences in the counts of total leukocytes, segmented neutrophils, lymphocytes, or monocytes between male and female dogs.

Table 2

Results of Shapiro-Wilk normality testing, Mann-Whitney tests, and t tests to identify potential associations between sex and leukogram cell count for the 138 shelter dogs described in Table 1, grouped by age (< 3 months, ≥ 3 to ≤ 6 months, or > 6 months) and sex.

Cell type Dog age group Sex (No. of dogs) Mean* or median (range) cell count (103 cells/µL) P value sex data normality P value age data normality P value§ P value
Leukocytes < 3 mo Males (18) 14.6 (6.1–21.3)* 0.694 0.482 0.689
Females (16) 15.1 (8.5–21.0)* 0.751
≥ 3 to ≤ 6 mo Males (8) 12.4 (9.6–28.3) 0.004 < 0.050 0.393
Females (14) 13.6 (9.1–23.2) 0.471
> 6 mo Males (35) 13.0 (6.7–22.3) 0.652 < 0.050 0.344
Females (47) 11.6 (6.7–25.2) 0.002
Neutrophils < 3 mo Males (18) 9.0 (3.7–13.0)* 0.903 0.877 0.188
Females (16) 10.3 (5.2–17.2)* 0.848
≥ 3 to ≤ 6 mo Males (8) 7.7 (5.4–23.5) < 0.001 < 0.050 0.357
Females (14) 8.9 (5.0–18.1) 0.191
> 6 mo Males (35) 8.4 (4.9–18.5) 0.018 < 0.050 0.873
Females (47) 8.4 (3.9–18.8) 0.003
Lymphocytes < 3 mo Males (18) 4.3 (1.5–7.5)* 0.154 0.427 0.501
Females (16) 3.5 (1.0–5.4)* 0.529
≥ 3 to ≤ 6 mo Males (8) 3.8 (2.6–8.4) 0.054 < 0.050 0.193
Females (14) 3.2 (0.3–8.5) 0.041
> 6 mo Males (35) 2.6 (0.1–7.6) 0.009 < 0.050 0.590
Females (47) 2.3 (0.6–5.0) 0.010
Monocytes < 3 mo Males (18) 0.8 (0–2.1)* 0.134 0.145 0.705
Females (16) 0.9 (0.1–1.5)* 0.062
≥ 3 to ≤ 6 mo Males (8) 0.6 (0.2–1.2)* 0.477 0.128 0.053
Females (14) 0.9 (0.4–1.9)* 0.189
> 6 mo Males (35) 0.7 (0–1.8) 0.105 < 0.050 0.713
Females (47) 0.6 (0–3.3) < 0.001

Values of P ≤ 0.05 were considered significant.

*Data are reported as mean and range.

†Data are reported as median and range.

‡Shapiro-Wilk test was performed to test whether dogs of either sex had normal distribution of data within each age group (ie, leukocyte counts in male dogs < 3 months old).

§Mann-Whitney test (for nonnormally distributed data) was used to compare median leukogram results across sexes within each age group.

t Test (for normally distributed data) was used to compare mean leukogram results across sexes within each age group.

— = Test not performed.

One dog’s CBC was characterized as a stress leukogram (age ≥ 3 to ≤ 6 months). Eleven dogs had a physiologic leukocytosis (6 dogs < 3 months, 1 dog ≥ 3 to ≤ 6 months, and 4 dogs > 6 months old). Twenty-eight dogs had CBCs characterized as a chronic inflammatory leukogram (8 dogs < 3 months old, 3 dogs ≥ 3 to ≤ 6 months old, and 17 dogs > 6 months old), and no dog had an acute inflammatory leukogram based on leukocyte counts alone. The remaining dogs with leukocytosis (n = 23) had mixed cellular patterns that did not fit into a standard definition.

Infection and parasitism

Forty-seven of 138 (34.1%) dogs had evidence of an infection or parasite on the day of presentation (Table 3), including 9 dogs < 3 months old, 7 dogs ≥ 3 to ≤ 6 months old, and 31 dogs > 6 months old. Seven dogs had 2 infections or parasites identified (1 dog < 3 months old, 1 dog ≥ 3 to ≤ 6 months old, and 5 dogs > 6 months old).

Table 3

Signs of infection, infectious agents, and parasites identified in 47 of the 138 shelter dogs described in Table 1 grouped by age and with median (range) leukogram results reported for each group.

Overall By age group Median (range)
Sign or agent No. (%) of dogs Age No. of dogs Total leukocytes (103 cells/µL) RI, 4.3–13.6 Segmented neutrophils (103 cells/µL) RI, 2.5–9.3 Lymphocytes (103 cells/µL) RI, 0.8–4.3 Monocytes (103 cells/µL) RI, 0.1–0.9 Eosinophil (103 cells/µL) RI, 0–1.5
Persistent pyrexia 1 (0.7) > 6 mo 1 16.8 12.8 2.4 0.7 1.0
Active skin lesion 20 (14.5) > 6 mo 14 13.6 (7.0–25.2) 9.9 (5.5–17.8) 1.9 (0.7–7.6) 0.8 (0.1–3.3) 0.4 (0–1.4)
≥ 3 to ≤ 6 mo 3 16.5 (9.6–19.0) 7.8 (5.4–11.6) 4.4 (3.2–8.4) 0.8 (0.2–1.5) 0.3 (0.2–1.3)
< 3 mo 3 13.8 (13.6–19.4) 12.0 (8.1–14.4) 3.9 (1.0–4.1) 0.5 (0.4–0.7) 0.6 (0.1–1.1)
Otitis externa 2 (1.4) > 6 mo 2 14.6 (14.0- 15.1) 9.6 (9.2- 9.9) 2.9 (2.2–3.6) 0.8 (0.8–0.8) 1.3 (1.0–1.5)
Vaginitis 1 (0.7) ≥ 3 to ≤ 6 mo 1 9.9 5.6 2.5 0.5 1.3
Fleas or flea dirt 12 (8.7) > 6 mo 10 11.8 (7.3–18.1) 7.6 (4.7–14.1) 2.4 (1.8–3.6) 0.7 (0.1–1.8) 0.4 (0–4.5)
≥ 3 to ≤ 6 mo 1 13.1 9.6 2.9 0.5 0.1
< 3 mo 1 8.5 5.2 2.9 0.4 0
Anaplasma phagocytophilum 4 (2.9) > 6 mo 4 15.0 (11.5–20.9) 9.5 (8.2–11.1) 4.1 (1.6–6.5) 0.6 (0.3–1.2) 1.1 (0.1–2.9)
Ehrlichia canis 4 (2.9) > 6 mo 3 10.4 (9.1–12.4) 6.4 (6.2–7.6) 3.0 (1.0–3.1) 0.5 (0.2–1.1) 0.7 (0.6–1.2)
≥ 3 to ≤ 6 mo 1 12.2 6.6 3.9 1.2 0.5
Toxocara 3 (2.2) < 3 mo 3 14.6 (12.1–21.0) 11.4 (9.4–17.2) 1.8 (1.5–3.4) 0.7 (0.4–0.8) 0.4 (0–0.7)
Ancylostoma 2 (1.4) ≥ 3 to ≤ 6 mo 1 19.0 11.6 4.4 1.5 1.3
< 3 mo 1 14.6 11.4 1.8 0.7 0.7
Taenia 1 (0.7) < 3 mo 1 17.8 9.8 5.2 1.4 1.4
Coccidia 1 (0.7) ≥ 3 to ≤ 6 mo 1 12.4 8.7 2.9 0.7 0.1
Parvovirus 1 (0.7) < 3 mo 1 11.9 10.1 1.5 0 0
Heartworm 1 (0.7) > 6 mo 1 9.0 6.2 1.5 0.6 0.6

RI = Reference interval.

One dog was reported to be lethargic (< 3 months old; promptly diagnosed with parvovirus), while 19.6% (27/138) were quiet, alert, and responsive and 79.7% (110/138 dogs) were bright, alert, and responsive. Six dogs initially had increased rectal temperature (> 39.7 °C); 5 of those dogs had temperature return to normal when rechecked within 24 hours, and 1 dog (> 6 months old) had persistent pyrexia of 40.1 °C. No dog showed respiratory signs (nasal discharge, sneezing, or cough). Ten percent (14/138) of dogs had diarrhea or soft stools, and 1 dog vomited during the initial examination. Fourteen percent (19/138) of dogs had active skin lesions (defined as open wounds or pyoderma), and 2 dogs had otitis externa. Nine percent (12/138) of dogs had live fleas or flea dirt. One dog had vaginitis. No additional clinical signs or examination findings were recorded that would suggest an infectious or inflammatory disease.

Fecal samples were collected from 14 dogs with diarrhea or soft stools to perform fecal flotation, which confirmed parasitism in 6 dogs (Toxocara alone [n = 2], Toxocara and Ancylostoma [1], Ancylostoma alone [1], Taenia alone [1], Coccidia alone [1]). Three of these 14 dogs had concurrent lethargy, vomiting, bloody diarrhea, or leukopenia (alone or in combination) and thus were tested for parvovirus antigen. One dog (a male intact < 3 months old and having received 1 parvovirus vaccine 13 days prior to presentation) was confirmed positive for parvovirus, and surgery was postponed for that dog.

One dog tested positive for heartworm antigen. The dog was not coughing, and thoracic radiographs were unremarkable; thus, surgery was performed as scheduled. All dogs tested negative for B burgdorferi. Four dogs tested positive for E canis antibodies; however, none were febrile or thrombocytopenic. Four dogs tested positive for A phagocytophilum antibodies; none were febrile, but 1 dog was thrombocytopenic (51,000 cells/µL; RI, 130,00 to 370,000 cells/µL). Surgery was postponed for the A phagocytophilum–positive and thrombocytopenic dog, and medical treatment was initiated.

The presence of recognized infection or parasitism was not associated with leukocytosis (P = 0.730). Forty-three percent (20/47) of dogs with a recognized infection or parasite also had a leukocytosis, and 31.7% (20/63) of dogs with a leukocytosis had a recognized infection or parasite. When only dogs < 3 months were considered, 55.6% (5/9) of dogs with a recognized infection or parasite also had a leukocytosis and 20.8% (5/24) of dogs with leukocytosis had a recognized infection or parasite (P = 0.395). Of 10 dogs with leukocyte counts > 20,000 cells/µL (range, 20,900 to 28,300 cells/µL), 2 dogs had active skin lesions (25,200 cells/µL with 500 nonsegmented neutrophil count, and 21,400 cells/µL), 1 dog had anaplasmosis (20,900 cells/µL), and 1 dog had toxocariasis (21,000 cells/µL), while 6 dogs did not have identified infections or parasites. Eosinophilia was rare among dogs with documented infections and parasites, seen only in a dog that tested positive for Anaplasma (2,900 cells/µL) but not in any dogs with gastrointestinal parasites.

Treatment and surgery

On the day of presentation, all 138 dogs received a single oral dose of praziquantel, pyrantel pamoate, and febantel (Drontal Plus) according to the FDA-approved label. One dog with coccidiosis was treated with ponazuril (30 mg/kg, PO, q 24 h for 3 days). Dogs that tested negative for heartworm antigen (137/138) also received a single dose of FDA-approved heartworm preventative; specific product administered depended on product availability during the study period. The dog that was parvovirus positive was treated medically in our intensive care unit’s isolation for 2 days with classic parvovirus signs of vomiting, diarrhea, lethargy, and inappetence and then made a full recovery. One thrombocytopenic dog that tested positive for A phagocytophilum was treated with doxycycline (4.2 mg/kg, PO, q 12 h for 21 days). Four additional dogs were treated with antimicrobials (cefazolin [n = 2], amoxicillin-clavulanate [1], and cephalexin [1]) for skin wounds or pyodermas.

Elective OHE or castration was successfully performed as scheduled for 136 of the 138 (98.6%) dogs. Two dogs had surgery postponed due to parvovirus (leukocyte count, 11,900 cells/µL) or anaplasmosis-related thrombocytopenia (leukocyte count, 11,500 cells/µL). Among the 63 dogs with leukocytosis, all had surgery and no dog had anesthetic, surgical, or postoperative complications attributable to a condition that could be indicated by their leukogram. All dogs were discharged with instructions for postoperative care, and recommendations were made for the treatment of identified infections or parasites; dogs with leukocytosis above 20,000 cells/µL were recommended to have an examination and CBC rechecked at their suture-removal veterinary visit.

Discussion

This study was designed to determine whether shelter dogs presenting for elective OHE or castration have higher leukocyte counts than RIs and to describe the leukocyte patterns seen in this population of dogs. The study also aimed to determine whether leukocytes are associated with age and common infections seen in shelter dogs and whether leukocytosis precludes progression to surgery. Leukocytosis was found in 45.6% (63/138) of dogs, with higher leukocyte and lymphocyte counts in dogs < 3 months old than in dogs > 6 months old. Although we hypothesized that leukocytosis in these dogs would be most likely from a stress leukogram due to their shelter experience, only 1 dog had a stress leukogram. Similarly, although infection or parasitism was identified in 34.1% (47/138) of dogs, there was no association with leukocytosis. Only 2 dogs did not proceed with surgery, and all dogs with leukocytosis had uneventful surgeries. These results suggested that a CBC with leukogram is not a necessary preanesthetic screening test for shelter dogs before elective surgery, and instead, limited resources should be spent on targeted diagnostic testing for individual dogs when illness is identified before anesthesia.

It was common to find total leukocyte counts above the adult RI in this population of dogs from shelters, especially in the juvenile dogs. Dogs < 3 months of age had higher total leukocyte counts than did older dogs, and only 20.8% (5/24) of those dogs < 3 months of age with high leukocyte counts had a recognized infection or parasite. A complete evaluation was not performed to rule out all causes of infection or inflammation that could increase leukocyte counts, and a normal pattern does not rule out infectious or inflammatory disease. However, these data suggest that juvenile shelter dogs do have a higher leukocyte count than adults, as has been found in healthy research Beagles,11 and that age-matched RI, when available, should be considered when interpreting leukograms in puppies.

Shelter dogs of all ages have been shown to have increased leukocyte counts and cortisol concentrations, attributed to stress from their environment.6 In the present study, while stress was suspected to be the cause for the leukocytosis, only 1 dog was characterized as having a stress leukogram based on laboratory RI. However, applying the definition of stress leukogram to dogs of varying ages while only RIs established with samples from adult dogs were used could result in misclassification. Lymphocyte counts are highest (5,900 cells/µL) in healthy Beagles from 2 to 4 months of age,11 and the present study found that 41.1% (14/34) of shelter dogs < 3 months of age and 18.2% (4/22) of shelter dogs ≥ 3 to ≤ 6 months of age had a lymphocyte count above the high end of the adult RI (4,300 cells/µL). Thus, even with a stress-induced reduction of lymphocytes in juvenile dogs, the absolute count might remain above or within the adult RI. Therefore, a stress response likely occurred more often than was documented in this study and might be overlooked if age-specific RIs are not used.

A physiologic leukocytosis was identified in 11 dogs and represents the classic catecholamine-induced fight-or-flight response from excitement, fright, pain, exercise, or anxiety.7,16 With these stressors, lymphocytes shift from the marginated to the circulating lymphocyte pool, creating lymphocytosis as the differentiating hallmark of this response.7 Although considered uncommon in dogs, it would be expected to see this response in some shelter dogs presenting for elective surgery.6 However, a leukogram could be mislabeled and overinterpreted as a physiologic leukocytosis in a juvenile dog because the lymphocyte count is naturally higher even in healthy juvenile dogs.

In most dogs with leukocytosis, the alterations were mild and not clinically relevant. A chronic inflammatory leukogram was most common, likely reflecting identified or potential subclinical infections present in this population. Ten dogs had leukocytosis > 20,000 cells/µL (range, 20,900 to 28,300 cells/µL), with 4 having identified infections and 6 having no infection or parasite identified. If identified on a routine yearly examination or presurgical screening, this degree of leukocytosis would typically warrant a recheck CBC and possible further diagnostic evaluation for infectious and inflammatory disease, as recommended in the discharge instructions for the shelter dogs in this study. Because 136 of the 138 (98.6%) dogs in this study proceeded to surgery without complication, including all 63 dogs that had leukocytosis, it was concluded that the leukogram shows little benefit for presurgical screening in dogs from shelters undergoing routine elective procedures such as OHE or castration. As the leukogram adds additional cost, time, and resources for both the veterinary personnel and shelter or dog owner, it should be reserved for dogs that are identified on examination as appearing ill. Because dogs’ clinical status can change rapidly, a thorough examination the day of surgery is needed to determine surgical candidacy. The 1 dog with parvovirus in this study, a < 3-month-old male intact Labrador, was deemed healthy prior to presentation but appeared lethargic and developed vomiting and diarrhea during our initial examination. A dog with this signalment and clinical signs is at high suspicion for parvovirus, thus a parvovirus test and CBC were both warranted. While it was interesting that this dog’s leukocyte count was within RI, it is common for leukopenia to lag behind the gastrointestinal signs of parvoviral infection.17

In the present study, 6 dogs initially presented with a rectal temperature of ≥ 39.7 °C. Inflammatory conditions (including infectious, immune-mediated, or neoplastic) can result in a fever or pyrexia caused by an elevated hypothalamic set point.18 In contrast, environmental heat, exercise-induced hyperthermia, malignant hyperthermia, and seizures can result in nonfebrile hyperthermia with no change in hypothalamic set point.18 In dogs, temperature can also fluctuate due to stress (including separation, introduction of strangers, and examination), as well as excitement.19,20 As 5 of the 6 dogs in this study with initial hyperthermia returned to normal rectal temperature in 24 hours, no further evaluation was required. The 1 dog with persistent pyrexia had a traumatic wound on his tail and a mild chronic inflammatory leukogram (leukocyte count, 16,800 cells/µL). Dogs with persistent pyrexia would benefit from a CBC preoperatively, and additional diagnostic testing might be warranted to determine the underlying cause and direct appropriate treatment.21,22

A limitation of this study was that vaccination protocols were not standardized for dogs prior to enrollment; thus, it was not possible to make meaningful conclusions about the effect of vaccines on leukograms. In dogs, data are sparse regarding the effect of vaccination on postvaccination leukograms but suggest that lymphocyte counts are increased by day 7 after vaccination due to antigenic stimulation.23,24 These data suggest that recent vaccination might complicate interpretation of CBC results in dogs, and future studies are warranted to better elucidate the exact timing, effect on different leukocyte populations, and differences among various vaccines (ie, infectious agent and formulation).

Additional limitations of this study included incomplete medical records from shelters regarding administration of medications that could affect leukocyte counts; no dog was reported to have received glucocorticoids, but it is possible this could have been omitted from submitted records. Due to financial limitations, limited evaluations were performed to confirm or rule out presence of infection in enrolled dogs with leukocytosis. This could have resulted in underreporting of infections in dogs in this population. Specifically, it is possible that gastrointestinal parasites were underdiagnosed with students performing fecal flotations and intermittent shedding of parasites; additional cases of parasitic disease might have been identified if feces had been submitted to the parasitology laboratory, students consistently used centrifugation, or fecal floats were repeated. Instead, since dogs appeared stable, they had surgery as planned and were provided recommendations for follow-up. Another limitation was that there was much overlap of definitions of leukogram patterns.7,16 Additional testing, such as measuring cortisol concentrations, might have further helped categorize patient leukograms. However, the number of dogs in each category was considered less important than recognizing that dogs in this study likely had several confounding influences on their leukogram, including stress, physiologic factors, inflammation or infection, recent vaccines, and age. Despite the changes these influences might have had on the leukograms, no dog had surgery postponed due to leukogram concerns. A final limitation was that there were both normally and nonnormally distributed data in our data set, necessitating a mixture of parametric and nonparametric tests for comparing leukogram data between groups of dogs.

In conclusion, our findings indicated that, as hypothesized, leukocytosis is common in shelter dogs presenting for elective OHE or castration, yet it is typically mild to moderate; all dogs were able to proceed with surgery. Leukogram differences existed between juvenile and adult dogs, with dogs < 3 months of age having higher total leukocyte and lymphocyte counts than did adults, and leukocytosis was not associated with the presence of identified infection or parasites. When presurgical examination suggests a dog is ill or infection is suspected, a leukogram might be helpful and an age-specific RI should be used. For dogs with no identified illness or infection, presurgical CBC is not necessary and resources can be responsibly allocated elsewhere.

Acknowledgments

This study was funded by the Kansas State University Department of Clinical Sciences, a private anonymous donor, and a Kansas State University Pet Tribute Grant. Scholar funding was provided in part by the Boehringer Ingelheim Veterinary Scholars program and in part by the Kansas State University Veterinary Research Scholars Program.

The authors declare there were no conflicts of interest.

References

  • 1.

    Grubb T, Sager J, Gaynor JS, et al. 2020 AAHA anesthesia and monitoring guidelines for dogs and cats. J Am Anim Hosp Assoc. 2020;56(2):5982. doi:10.5326/JAAHA-MS-7055

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2.

    Chandra A, Thakur V, Bhasin N, Gupta D. The role of pre-operative investigations in relatively healthy general surgical patients–a retrospective study. Anaesth Pain Intensiv Care. 2014;18(3):241244.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3.

    Benarroch-Gampel J, Sheffield KM, Duncan CB, et al. Preoperative laboratory testing in patients undergoing elective, low-risk ambulatory surgery. Ann Surg. 2012;256(3):518528. doi:10.1097/SLA.0b013e318265bcdb

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4.

    Alef M, von Praun F, Oechtering G. Is routine pre-anaesthetic haemotological and biochemical screening justified in dogs? Vet Anaesth Analg. 2008;35(2):132140. doi:10.1111/j.1467-2995.2007.00364.x

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5.

    Mitchell K, Barletta M, Quandt J, Shepard M, Kleine S, Hofmeister E. Effect of routine pre-anesthetic laboratory screening on pre-operative anesthesia-related decision-making in healthy dogs. Can Vet J. 2018;59(7):773778.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6.

    Dudley ES, Schiml PA, Hennessy MB. Effects of repeated petting sessions on leukocyte counts, intestinal parasite prevalence, and plasma cortisol concentration of dogs housed in a county animal shelter. J Am Vet Med Assoc. 2015;247(11):12891298. doi:10.2460/javma.247.11.1289

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7.

    Stockham SL, Scott MA. Leukocytes. In: Stockham SL, Scott MA, eds. Fundamentals of Veterinary Clinical Pathology. 2nd ed. Blackwell; 2008:53106.

    • Search Google Scholar
    • Export Citation
  • 8.

    Harper EJ, Hackett RM, Wilkinson J, Heaton PR. Age-related variations in hematologic and plasma biochemical test results in Beagles and Labrador Retrievers. J Am Vet Med Assoc. 2003;223(10):14361442. doi:10.2460/javma.2003.223.1436

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9.

    Prentice S, Kamushaaga Z, Nash SB, Elliott AM, Dockrell HM, Cose S. Post-immunization leukocytosis and its implications for the management of febrile infants. Vaccine. 2018;36(20):28702875. doi:10.1016/j.vaccine.2018.03.026

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10.

    Righi C, Menchetti L, Orlandi R, Moscati L, Mancini S, Diverio S. Welfare assessment in shelter dogs by using physiological and immunological parameters. Animals (Basel). 2019;9(6):340 doi:10.3390/ani9060340

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11.

    Anderson AC, Gee W. Normal blood values in the Beagle. Vet Med. 1958;53:135138.

  • 12.

    Shifrine M, Munn SL, Rosenblatt LS, Bulgin MS, Wilson FD. Hematologic changes to 60 days of age in clinically normal Beagles. Lab Anim Sci. 1973;23(6):894898.

    • Search Google Scholar
    • Export Citation
  • 13.

    Kustritz MV. Early spay-neuter: clinical considerations. Clin Tech Small Anim Pract. 2002;17(3):124128. doi:10.1053/svms.2002.34328

  • 14.

    Wiggs RB, Lobprise HB. Veterinary Dentistry Principles and Practice. Lippincott-Raven; 1997:97.

  • 15.

    KuKanich KS, Springer NL, Klutzke JB, KuKanich B. Comparisons of hematologic results for juvenile versus adult shelter dogs presented for ovariohysterectomy or castration. J Am Vet Med Assoc. 2021;259(3):275282. doi:10.2460/javma.259.3.275

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16.

    Latimer KS, Tvedten H. Leukocyte disorders. In: Willard MD, Tvedten H, Turnwald GH, eds. Small Animal Clinical Diagnosis by Laboratory Methods. 3rd ed. WB Saunders Co; 1999:5274.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17.

    Macartney L, McCandlish IA, Thompson H, Cornwell HJ. Canine parvovirus enteritis 1: clinical, haemotological and pathological features of experimental infection. Vet Rec. 1984;115(9):201210. doi:10.1136/vr.115.9.201

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 18.

    Lunn KA. Fever. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. Elsevier; 2012:11151123.

  • 19.

    Riemer S, Assis L, Pike TW, Mills DS. Dynamic changes in ear temperature in relation to separation distress in dogs. Physiol Behav. 2016;167:8691. doi:10.1016/j.physbeh.2016.09.002

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20.

    Travain T, Colomb ES, Heinzl EUL, Bellucci D, Prato-Previde E, Valsecchi P. Hot dogs: thermography in the assessment of stress in dogs (Canis familiaris)–a pilot study. J Vet Behav. 2015;10(1):1723. doi:10.1016/j.jveb.2014.11.003

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21.

    Chervier C, Chabanne L, Godde M, Rodriguez-Piñeiro MI, Deputte BL, Cadoré JL. Causes, diagnostic signs, and utility of investigations of fever in dogs: 50 cases. Can Vet J. 2012;53(5):525530.

    • Search Google Scholar
    • Export Citation
  • 22.

    Dunn KJ, Dunn JK. Diagnostic investigations in 101 dogs with pyrexia of unknown origin. J Small Anim Pract. 1998;39(12):574580. doi:10.1111/j.1748-5827.1998.tb03711.x

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23.

    Edreis SM, Albehwar AM, Sobhy NM, Zaghlool MA. Immunological and clinical studies on vaccinated dogs with the live attenuated canine adeno-1 virus vaccine. Egypt J Agric Res. 2018;96(1):305311.

    • Search Google Scholar
    • Export Citation
  • 24.

    Marinho Maciel R, dos Anjos Lopes ST, Melazzo Andrade Mazzanti C, et al. A hematologic and electrophoretic study in puppies vaccinated against canine distemper virus and canine parvovirus. Acta Sci Vet. 2012;40(1):16.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 876 0 0
Full Text Views 1511 1085 270
PDF Downloads 865 323 30
Advertisement