The raccoon dog (Nyctereutes procyonides) is a wild canid native to East Asia. Raccoon dogs are omnivores that feed on insects, rodents, birds, fish, and even human garbage. In Korea, many raccoon dogs are observed in urban areas due to the situation of overlap between their habitat and human residential areas. Consequently, cases of humans, domestic dogs, and raccoon dogs sharing the same diseases are commonly reported (3,7). Scabies is a representative disease in raccoon dogs. If infected, raccoon dogs show a pathognomonic clinical sign of wet hyperkeratosis, making the diagnosis relatively easy compared with other animals (5). As the infection progresses, the hyperkeratinization of the skin becomes crusted, which causes the weakened lower skin to crack and leads to severe chronic bleeding. A previous study reported significant decreases in the packed cell volume (PCV) and hemoglobin concentration in debilitated raccoon dogs with scabies infestation. However, even if severe anemia occurs due to a severe scabies infection, it is difficult to improve the situation through a blood transfusion in raccoon dogs because of the difficulty to find a donor; thus, medical treatment is necessary, but no cases of drug therapy for severe anemia in raccoon dogs have been reported.

This case report describes a patient in whom scabies infection and the resulting severe anemia that worsened during the treatment process improved through the administration of hematopoiesis-promoting factors and iron supplements.

An adult female free-ranging wild raccoon dog was rescued with cachexia. At the time of admission, the patient had little vitality, and the response to stimulation was unclear. Physical examination revealed hypothermia (35.6°C), a poor body condition (2 out of 5), severe dehydration (8-10%), pale mucus membranes, and generalized hyperkeratosis and alopecia (more than 70% of the body surface) consistent with scabies infestation. Complete blood count (CBC) and serum biochemistry parameters showed a significantly decreased red blood cell (RBC) count (2.48 × 10⁶ cells/μL), PCV (15%), hemoglobin concentration (5 g/dL), and glucose (36 mg/dL), while the WBC count (24 × 10⁶ cells/μL) and globulin (4.7 g/dL) concentration were increased (Table 1). A blood film examination showed neutrophilic inflammation with grade 1 toxic change and leptocytosis, indicating a mild regenerative response to the anemia (Fig. 1). Radiographic examination showed no specific findings. The patient was initially diagnosed with a scabies infection with secondary acute inflammation and a mild regenerative anemia presumed to be caused by chronic bleeding. A daily broad-spectrum antibiotic (30 mg/kg of cefazolin, IM, bid, Cefazolin Injection^®, Chongkundang, Seoul, Korea), daily non-steroidal anti-inflammatory (0.1 mg/kg of meloxicam, IM, bid, Metacam^®, Labiana Life Sciences, Barcelona, Spain), 0.8 ug/kg of darbepoetin alpha (DPO; SC, NESP^®, Kyowa Kirin Korea, Seoul, Korea), 10 mg/kg of iron dextran (IM, Prolonger^®, Elanco, Indianapolis, USA) and 56 mg/kg of oral fluralaner (Bravecto^®, MSD Animal Health, Korea) were administrated. Even though the patient’s condition was poor, the appetite was maintained; therefore, food and water were provided ad libitum. The patient was managed in the intensive care unit to maintain body temperature and provide oxygen.

Table 1 . Hematologic and serum biochemistry profile results from a raccoon dog rescued with scabies infection and cachexia at initial presentation.

Test	Parameter (unit)	Results	Reference interval	Reference
Complete blood count	RBC (×106/µL)	2.48	6.26 ± 1.19	4
	PCV (%)	15	40.00 ± 7.00
	Hemoglobin (g/dL)	5.0	12.90 ± 2.20
	WBC (×103/µL)	24.0	9.90 ± 3.75
	Neutrophil (×103/µL)	9.26	7.58 ± 3.66
	Lymphocyte (×103/µL)	8.18	2.19 ± 1.18
	Monocyte (×103/µL)	4.32	0.11 ± 0.15
	Eosinophil (×103/µL)	2.23	1.01 ± 1.12
	Basophil (×103/µL)	0	0.00 ± 0.00
Serum biochemistry profile	Total protein (g/dL)	6.8	6.7 ± 0.8	4
	Albumin (g/dL)	2.1	3.0 ± 0.5
	Globulin (g/dL)	4.7	5.89 ± 1.05	8
	A:G ratio	0.44	-
	AST (IU/L)	76	90.2 ± 86.3	4
	ALT (IU/L)	61	121.9 ± 148.5
	BUN (mg/dL)	57	27.1 ± 10.6
	Creatinine (mg/dL)	< 0.1	35.4 ± 17.7
	Total cholesterol (mg/dL)	356	64.32 ± 11.35	8
	Glucose (mg/dL)	36	111.17 ± 72.43	4
	Total bilirubin (mg/dL)	0	0.15 ± 0.08
	CPK (IU/L)	1,218	474.91 ± 217.26	8
	Amylase (IU/L)	1,503	2287.50 ± 338.75
	ALP (IU/L)	24	109.3 ± 96.0	4
	GGT (IU/L)	0	11.70 ± 5.08	8
	Sodium (mmol/L)	163	142.6 ± 2.6	4
	Potassium (mmol/L)	4.0	4.5 ± 0.5
	Chloride (mmol/L)	122	105.5 ± 4.1
	Calcium (mg/dL)	8.1	42.34 ± 3.60
	Phosphorus (mg/dL)	4.8	32.61 ± 9.37

Figure 1. A photo of blood film examination on day 1 showing the grade 1 toxic changes of neutrophils and leptocytosis. Diff-Quik stain, x100 objective.

On day 5 of hospitalization, however, despite indications of a regenerative response, the PCV decreased to 5.9%, and the patient’s condition decreased to the point where the raccoon dog only responded to a noxious stimuli (Fig. 2). Since it was assumed that the problem was caused by external bleeding from the skin lesions and rehydration caused by the water consumption being faster than the speed of the regenerative response, measures were planned to more rapidly increase the regenerative response. The same dosage of DPO injection was repeated with iron dextran on days 5 and 6, and the patient was monitored in the intensive care unit with oxygen supplementation in a warm environment. Despite the severe anemia and poor condition, the raccoon dog had an appetite but had difficulty raising the head and eating on its own; therefore, food was provided by force-feeding.

Figure 2. The graph illustrates time-dependent changes in the patient’s PCV, RBC count, and hemoglobin concentration. The red arrow indicates the day of darbepoetin alpha and iron dextran administration via SC and IM, respectively.

On day 10, a CBC showed that the PCV and hemoglobin had increased rapidly to 16.4% and 5.7 g/dL, respectively. A blood film examination revealed strong leptocytosis, indicating an active RBC regenerative response. As the hyperkeratinization and crusts caused by the scabies infection began to fall off, the skin lacerations and bleeding areas gradually began to crust over. On day 15, a CBC showed that the PCV and hemoglobin had gradually increased to 19.8% and 5.8 g/dL, respectively. By day 30, all the skin crusts had fallen off, and all of the lesions except alopecia had resolved. On day 36, the PCV exceeded 25%, and on day 45, the hemoglobin concentration exceeded 10 g/dL, showing that the severe anemia that was present at the beginning of hospitalization was resolved. A CBC that was reexamined on day 88 while waiting for the patient’s hair to grow back showed a PCV of 31.1% and a hemoglobin concentration of 11.4 g/dL. Although the raccoon dog’s fur did not fully grow back, the weather warmed up in July, and the animal’s condition considerably improved; therefore, the raccoon dog was finally released into the wild.

This report describes a case in which severe anemia in a raccoon dog was corrected without a blood transfusion by treating the primary cause of the anemia and repeatedly administering DPO and iron dextran. It is difficult to secure a raccoon dog capable of donating blood and to obtain enough donated blood due to the small body size of this animal (3 to 5 kg); thus, a blood transfusion is generally not easily performed to treat anemia in raccoon dogs. Due to this limitation, we selected DPO and iron dextran injections, which are hematopoiesis-promoting factors, as well as intensive care unit-based oxygen supplementation and temperature management. With these treatments and regular PCV monitoring, the patient finally achieved good results.

In dogs with severe anemia, blood transfusions are necessary to improve oxygen supply to tissues by increasing blood oxygen-carrying capacity (6). In addition to safety issues, various factors such as the patient’s PCV, hemoglobin concentration, mentation, exercise tolerance, heart rate, and respiratory rate must be considered when deciding to perform a blood transfusion. In dogs, a transfusion is usually indicated when the dog has clinical anemia (heart rate ≥160 beats/min, pale to white mucous membranes, depressed mentation, PCV <20%, hemoglobin concentration <7 g/dL, and signs of impaired oxygen delivery [hypoxemia and an elevated respiratory rate]), a coagulopathy, or deficiencies of specific plasma components. In the case of raccoon dogs, there is no information regarding the indications for a blood transfusion; however, considering that scabies-infected raccoon dogs develop gradual anemia and that their appetite and activity level are maintained in many cases with a PCV of 15 to 20%, it appears that a blood transfusion is not essential. However, this case is unique because the PCV, which was 15% at the time of the first examination, decreased dramatically to 5% due to rehydration caused by drinking water, and the patient maintained consciousness and had an appetite despite a severely decreased activity level. As the degree of hypoxemia in this patient was not monitored, it is difficult to determine the impact of the extreme decrease in the PCV on oxygen transport. Future research will be needed to discover the main causes of death and prognostic factors in scabies-infected raccoon dogs by comprehensively analyzing their physical examination findings, hematological data, and treatment results.

Although they belong to the same family, domestic dogs and raccoon dogs have different clinical symptoms of scabies infections. Unlike domestic dogs, which develop dry, easily shedding scales (2), the scales in raccoon dogs are moist and sticky and form crusts on the skin. As a result, scabies infection in raccoon dogs forms pathognomonic lesions that can be diagnosed through visual inspection. The skin cracks and bleeds due to the presence of these thick crusts, and when the face is affected, feeding activities become impossible due to the inability to open the eyes. It remains unclear why the scales of raccoon dogs are different from those of domestic dogs. But in the case of crusted scabies in humans, which form lesions similar to those of raccoon dogs, unlike ordinary scabies in humans, the difference in the immune cells (especially T cells) involved in the infection. The resulting cytokine responses are related to the different patterns of the symptoms (1). Further research is needed to identify the causes of differences in cutaneous clinical signs between raccoon dogs and domestic dogs, despite them sharing identical infectious agents and belonging to the same closely related family.

This subject was supported by the National Institute of Wildlife Disease Control and Prevention as “Specialized Graduate School Support Project for Wildlife Diseases Specialists”.

The authors have no conflicting interests.