Epidemiological survey and clinicopathological diagnosis of diarrhea in Korean native calves = 한우 송아지 설사에 대한 역학 조사와 임상병리학적 진단

다국어 초록 (Multilingual Abstract)

Epidemiological survey and clinicopathological diagnosis
of diarrhea in Korean native calves

Sung-Hwan Lee

Department of Veterinary Medicine
Graduate School, Kangwon National University

ABSTRACT

The clinical symptoms of calf diarrhea are very similar even if the causative agents are different. Therefore, identification of the causative agents and examination of blood values of diarrheal claves are essential for proper treatment of the patient and appropriate preventive measures. However, there are only a few small–scale studies of causative agents and no report on the blood gas analysis of diarrhea in Korean native calves (KNC). In addition, the reference range of blood variables for KNC is basically not reported. Therefore, the objectives of this study were to examine arterial and venous blood gas, electrolytes, and biochemical and hematological values in healthy KNC, to investigate causative agents and epidemiology of diarrhea in KNC, to determine blood values in KNC with diarrhea, and to investigate the relationship between blood values and clinical symptoms in KNC with diarrhea.
The arterial and venous blood samples from 62 healthy KNC within 3 weeks old were analyzed using a portable blood gas analyzer. Glucose (r=0.927) had the strongest correlations between arterial and venous values. The correlation between the values of the arterial and the venous blood was strong in creatinine (r=0.925), lactate (r=0.815), Ca2+ (r=0.806), Hct (r=0.799), Na+ (r=0.790), Hb (r=0.786), BE (r 0.749), pH (r=0.710), HCO3- (r=0.710), and tCO2 (r=0.663). The mean concentrations of glucose and lactate within 3 weeks old of KNC were higher than those of healthy adult cattle. The blood values according to age within 3 weeks old of arterial and venous blood variables were not significantly different (P>0.05). In this study, we could obtain the reference range of blood variables in KNC that can be used in clinical practice. In particular, pH, HCO3-, BE, Na+, Hct, Hb, glucose, lactate, and creatinine have diagnostic worth of venous blood, which is commonly used in the treatment of diarrheal calves.
The 14 causative agents were detected from 164 out of 207 diarrheal calves. Rotavirus was the most common causative agent (34.8%), followed by Eimeria spp (31.7%), E coli (22.0%), Giardia spp (14.0%), C difficile (9.8%), BVDV (8.5%,) coronavirus (7.9%), Cryptosporidium spp (7.3%), torovirus (6.7%), parvovirus (5.5%), norovirus (4.9%), kobuvirus (1.8%), adenovirus (1.2%), and Salmonella spp (0.6%). 95 (57.9%) out of 164 calves were infected by single causative agent and 69 (42.1%) calves were infected by multiple causative agents. Diarrhea caused by viral and bacterial agents was mainly a problem within 3 weeks old, but causative agents were detected up to 8 weeks old. Protozoal pathogen was mainly detected between 3 weeks and 10 weeks old. The prevalence of diarrhea was the highest in spring (46.3%), followed by winter (32.3%), summer (13.4%), and autumn (7.9%). The mortality rate caused by diarrhea was 7.9% in spring, 6.7% in winter, 3% in summer, and 0.6% in autumn, respectively (p<0.05). Most of the rotavirus and E coli induced severe watery diarrhea in KNC. Hemorrhagic diarrhea was observed in the cases of rotavirus, coronavirus, parvovirus, torovirus, E coli, C difficile, and Eimera spp infection. As calves were infected with multiple causative agents, the prevalence of hemorrhagic diarrhea was increased. However, there was no significant difference in mortality between single and mixed infected calves (p>0.05).
The most of diarrheal calves showed metabolic acidosis caused by loss of bicarbonate, hyponatremia, azotemia, and low level of pCO2. And the mean values of K+, Cl-, Hct, and Hb of diarrheal calves were in the upper limit of reference range. More than 50% of calves had higher BUN values. BUN was the most sensitive indicator of change of physical activity status and dehydration(p≤0.001). The values of pH, BE, and AnGap were also highly related to physical deterioration and dehydration (p≤0.001).
In conclusion, this study provided reference ranges on arterial and venous blood gas, electrolytes, and biochemical and hematological variables in healthy KNC which can be used for diagnosis of calf diseases. And this study elucidated the causative agents and their epidemiology of diarrhea in KNC. This study also confirmed the relationship between blood values and clinical symptoms in KNC with diarrhea. Comprehensive recent information on diarrhea of KNC obtained in this study will be helpful for clinical practitioners to treat and control of diarrhea of KNC.

Key words: Korean native calves, blood gas analysis, reference range, diarrhea, causative agents, epidemiology, physical activity, dehydration.

국문 초록 (Abstract)

한우 송아지 설사에 대한 역학 조사와 임상병리학적 진단

이 성 환

강원대학교 대학원 수의학과

감염성 송아지 설사는 원인체가 다양하지만 원인체가 다른 경우에도 임상증상은 매우 유사하다. 그러므로 환자의 적절한 치료와 예방 조치를 위해서는 설사 원인체의 정확한 진단과 혈액학적, 전해질, 산-염기 및 혈액화학적 검사가 필수적이다. 그러나 한우 송아지의 설사 원인체와 임상병리학적 연구는 희소한 실정이며 정상 한우 송아지의 혈액학적, 혈액화학적, 전해질 및 산-염기에 대한 기준 범위(reference range)도 보고되지 않은 실정이다. 본 연구는 건강한 한우 송아지의 동맥 및 정맥혈액의 혈액가스, 전해질, 생화학적 및 혈액학적 측정치를 조사하고, 한우 송아지의 설사 원인체와 발생역학을 조사하며, 설사를 하는 한우 송아지 혈액의 임상병리학적 측정치를 조사하고 임상증상과 혈액학적 측정치 간의 관련성을 조사하는 것을 목적으로 하였다.
3 주령 이내의 건강한 한우 송아지 62두의 동맥 및 정맥 혈액 샘플을 휴대용 혈액가스분석기를 사용하여 즉시 분석하였다. 포도당 (r=0.927)은 동맥과 정맥의 값 사이에 가장 강한 상관관계를 보였으며 동맥혈과 정맥혈의 creatinine(r=0.925), 젖산 (r=0.815), Ca2+ (r=0.806), Hct (r=0.799), Na+ (r=0.790), BE (r=0.749), pH (r=0.710), HCO3- (r=0.710) 및 tCO2 (r=0.663)에서도 강한 상관관계를 나타냈다. 송아지의 포도당과 젖산의 평균 농도는 성우의 측정치보다 높았다. 3 주령 이내 송아지의 동맥 및 정맥혈액의 각 측정치는 주령에 따라 유의한 차이가 나타나지 않았다 (P>0.05). 본 연구에서는 임상에서 참고치가 될 한우 송아지 혈액의 기준 범위(reference range)를 구할 수 있었다. 특히, 정맥혈액의 pH, HCO3-, BE, Na+, Hct, Hb, glucose, creatinine 및 젖산의 측정치는 동맥혈액 대신에 임상에서 송아지 설사 치료에 이용할 수 있는 유용한 측정치로 판단되었다.
총 207 마리의 설사하는 송아지 중 164 마리에서 14 종류의 설사원인체가 검출되었으며 그 중에 Rotavirus가 가장 흔한 원인체 (34.8 %)이었고, Eimeria spp (31.7 %), E coli (22.0%), Giardia spp (14.0%), C difficile (9.8%), BVDV (8.5%), coronavirus (7.9%), Cryptosporidium spp (7.3%), torovirus (6.7%), parvovirus (5.5%), norovirus (4.9%), kobuvirus (1.8%), adenovirus (1.2%) 및Salmonella spp (0.6%) 순으로 검출되었다. 164 마리의 송아지 중 95 마리 (57.9%)가 단일 원인체에 감염되었으며 69 마리 (42.1%)는 여러 원인체에 혼합감염 되었다. 바이러스 및 세균에 의한 설사는 주로 생후3 주 이내에 발생하였지만 원인체는 8 주까지 검출되었으며 원충은 주로 3 주에서 10 주 사이에 검출되었다. 설사의 발생률은 봄 (46.3 %)이 가장 높았고 겨울 (32.3%), 여름 (13.4%) 및 가을 (7.9%) 순이었으며 설사로 인한 사망률도 봄 (7.9%), 겨울 (6.7%), 여름 (3%) 및 가을 (0.6%) 순이었다 (p<0.01). 대부분의 rotavirus와 대장균은 심한 수양성 설사를 일으켰으며 출혈성 설사는 rotavirus, coronavirus, parvovirus, torovirus, 대장균, C difficile 및 Eimeria spp 감염의 경우에 관찰되었다. 송아지가 여러 원인체에 혼합감염 될 경우 출혈성 설사의 발생이 증가하였으나 단일 및 혼합 감염된 송아지 사이의 사망률에는 유의한 차이가 없었다 (p>0.05). 설사하는 송아지는 주로 대사성 산증, 저나트륨혈증, 고질소혈증을 나타내었으며, K+, Cl-, Hct와 Hb의 평균값은 기준 범위의 상한선에 있었다. 또한 설사하는 송아지의 70 % 이상이 중탄산염의 소실로 인한 대사성 산증을 나타내었다. BUN은 신체 활성 변화와 탈수에 가장 민감한 지표였으며 pH, BE 및 AnGap도 신체활성 및 탈수와 관련이 높았다 (p≤0.001). HCO3-, BE, AnGap, K+, Cl-, Hct 및 Hb 측정치는 설사하는 송아지의 신체 상태와 탈수와 관련하여 임상 증상을 평가하는데 유용한 지표가 될 뿐만 아니라 탈수, 전해질 및 산-염기 불균형의 교정을 위한 수액 치료에 유용하게 이용될 수 있었다.
이 연구에서 얻어진 정상 한우 송아지의 혈액학적, 혈액화학적, 전해질 및 산-염기와 관련된 기준 범위는 송아지 질병진단에 유용한 정보를 제공하였다. 그리고 본 연구에서 얻은 송아지 설사 원인체와 역학 조사의 결과들은 최근 국내에서 발생하는 송아지 설사에 대한 이해력을 높이는데 기여한 것으로 판단된다. 설사하는 한우 송아지의 혈액학적, 혈액화학적, 전해질 및 산-염기와 관련된 측정치들은 임상가들이 송아지 설사를 진단할 때 중요한 판단 기준으로 활용될 수 있을 것이다. 또한 이들 측정치와 신체 활성도 및 탈수 정도와의 상관성은 임상가들이 실험실적 진단 없이 임상증상에 근거하여 수액 처치를 실시하는데 도움을 줄 것으로 판단된다










주요어; 한우 송아지, 설사, 혈액가스분석, 기준범위, 원인체, 역학, 신체활성도, 탈수.

목차 (Table of Contents)

• CONTENTS
• ABSTRACT -----------------------------------------ⅰ
• CONTENTS -----------------------------------------ⅳ
• LIST OF ABBREVIATIONS -------------------------------ⅵ
• LIST OF TABLES --------------------------------------ⅶ
• LIST OF FIGURES -------------------------------------ⅸ
• CHAPTER Ⅰ
• General introduction --------------------------------- 1
• CHAPTER Ⅱ
• Arterial and venous blood gases, electrolytes, and biochemical and hematological values healthy Korean native calves
• ABSTRACT--------------------------------------- 17
• INTRODUCTION ------------------------------------ 18
• MATERIALS AND METHODS-----------------------------20
• RESULTS ---------------------------------------- 23
• DISCUSSION -------------------------------------- 29
• CHAPTER Ⅲ
• Causative agents and epidemiology of diarrhea in Korean native calves
• ABSTRACT ---------------------------------------34
• INTRODUCTION ------------------------------------36
• MATERIALS AND METHODS ---------------------------38
• RESULTS ----------------------------------------45
• DISCUSSION - ------------------------------------63
• CHAPTER Ⅳ
• Relationship between values of blood variables and physical status in Korean native calves with diarrhea
• ABSTRACT ---------------------------------------73
• INTRODUCTION ------------------------------------74
• MATERIALS AND METHODS - ---------------------------77
• RESULTS ---------------------------------------- 80
• DISCUSSION- ------------------------------------- 89
• CHAPTER Ⅴ
• General discussion ---------------------------------94
• REFERENCES --------------------------------------102
• ABSTRACT IN KOREAN -------------------------------118
• LIST OF ABBREVIATIONS
• AnGap: Anion Gap
• BE: Base excess
• BUN: Blood urea nitrogen
• BVDV: Bovine viral diarrhea virus
• C difficile: Clostridium difficile
• Ca2+: Calcium ion
• Cl-: Chloride ion
• E coli : Escherichia coli
• Glu: Glucose
• Hb: Hemoglobin
• HCO3-: Bicarbonate ion
• Hct: Hematocrit
• K+: Potassium ion
• KNC: Korean native calves
• Na+: Sodium ion
• OPG: Oocysts per gram
• PCO2: Partial pressure of carbon dioxide
• PCR: Polymerase chain reaction
• RT-PCR: Reverse transcription polymerase chain reaction
• SO2: Oxygen saturation
• TCO2: Total carbon dioxide
• LIST OF TABLES
• CHAPTER Ⅱ
• Table 2-1. Mean ± standard deviations (SD) values and reference ranges of arterial and venous blood variables and correlation coefficients between arterial and venous blood variables (n=62)---------------26
• Table 2-2. Values of blood gases, hematologic, and chemistry of arterial blood according to age ------------------------------27
• Table 2-3. Values of blood gases, hematologic, and chemistry of venous blood according to age ------------------------------38
• CHAPTER Ⅲ
• Table 3-1. Viruses, primer sequences, product sizes, and PCR or RT-PCR conditions for viruses --------------------------42
• Table 3-2. The target gene of bacteria, primer sequences, product sizes of PCR, and PCR conditions -------------------------------43
• Table 3-3. The target gene of protozoa, primer sequences, product size of PCR, and PCR conditions -------------------------------44
• Table 3-4. Prevalence of single infected calves by causative agent (n=95) from diarrheal KNC (n=164) --------------------------48
• Table 3-5. Prevalence of mixed infected calves by causative agents (n=69) from diarrheal KNC (n=164) --------------------------49
• Table 3-6. Prevalence of single or mixed infected causative agents (n=257) detected from diarrheal KNC (n=164) -----------------50
• Table 3-7. Seasonal distribution of the causative agents (n=257) detected in 164 diarrheal KNC (n=164) --------------------------57
• Table 3-8. Fecal forms of single and mixed infection (n=257) according to the causative agents of diarrheal calves (n=164) --------------61
• CHAPTER Ⅳ
• Table 4-1. Mean ± standard deviations (SD) of the blood values of diarrheal calves
• (n=180) -----------------------------------81
• Table 4-2. Changes of blood values according to physical activity status (n=180)
• ----------------------------------------86
• Table 4-3. Evaluation of blood values according to dehydration degree (n=180)
• ----------------------------------------88
• LIST OF FIGURES
• CHAPTER Ⅲ
• Fig 3-1. Prevalence of causative agents detected from 164 diarrheal calves. --47
• Fig 3-2. Distribution of major causative agents infected single and mixed according
• to onset age of diarrhea (Rotavirus (p≤0.001), coronavirus, BVDV, E coli, C difficile, Eimeria spp (p≤0.001), Cryptosporidium spp, and Giardia spp (p<0.01)). ------------------------------------54
• Fig 3-3. Seasonal comparison of prevalence of diarrhea and mortality caused by diarrhea in KNC (n=164). --------------------------58
• Fig 3-4. Distribution of fecal forms in 52 diarrheal calves detected Eimeria spp according to oocysts per gram (OPG). OPG was classified as OPG 1, 1,000 or less; OPG 2, 1,000 to 10,000; and OPG 3, 10,000 or more. ------62
• CHAPTER Ⅳ
• Fig 4-1. Distribution of diarrheal calves in reference range, low, and high level of blood variables (n=180). BE, base excess; tCO2, total carbon dioxide; HCO3-, bicarbonate; Na+, sodium; Glu, glucose; pCO2, partial pressure of carbon dioxide; Cl-, chloride; K+, potassium; Hct, hematocrit; Hb, hemoglobin; AnGap, anion gap; and BUN, blood urea nitrogen. -----84