• 1. California Department of Forestry and Fire Protection. Stats and Events. Available at: www.fire.ca.gov/. Accessed Oct 18, 2019.

  • 2. Duclos P, Sanderson LM, Lipset M. The 1987 forest fires disaster in California: assessment of emergency room visits. Arch Environ Health 1990;45:5358.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Madigan JE, Rowe JD, Angelos JA, et al. Wildlife associated burn injury of 1400 sheep in Northern California: a coordinated mass casualty veterinary response. Prehosp Disaster Med 2011;26 (suppl 1):S90S91.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. California Veterinary Medical Association. California Veterinary Medical Reserve Corps (CAVMRC) volunteer handbook. Sacramento: California Veterinary Medical Association, 2019. Available at: cvma.net/resources/disaster-response-program-2/california-veterinary-medical-reservecorps-cavmrc/california-veterinary-medical-corps-cavmrc-information/. Accessed May 18, 2020.

    • Search Google Scholar
    • Export Citation
  • 5. Pavletic MM, Trout NJ. Bullet, bite, and burn wounds in dogs and cats. Vet Clin North Am Small Anim Pract 2006;36:873893.

  • 6. Hanson RR. Management of burn injuries in the horse. Vet Clin North Am Equine Pract 2005;21:105123.

  • 7. Food Animal Residue Avoidance Data Bank. Prohibited and restricted drugs in food animals. Available at: farad.org/prohibited-and-restricted-drugs.html. Accessed Sep 30, 2019.

    • Search Google Scholar
    • Export Citation
  • 8. Patsouris D, Qi P, Abdullahi A, et al. Burn induces browning of the subcutaneous white adipose tissue in mice and humans. Cell Rep 2015;13:15381544.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9. Wilmore DW, Long JM, Mason AD Jr, et al. Catecholamines: mediator of the hypermetabolic response to thermal injury. Ann Surg 1974;180:653669.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Herndon DN, Wilmore DW, Mason AD Jr. Development and analysis of a small animal model simulating the human postburn hypermetabolic response. J Surg Res 1978;25:394403.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Herndon DN, Curreri PW, Abston S, et al. Treatment of burns. Curr Probl Surg 1987; 24:341397.

  • 12. Fox SM. Management of thermal burns, part 1. Compend Contin Educ Pract Vet 1985;7:631642.

  • 13. Geiser D, Walker RD. Management of large animal thermal injuries. Compend Contin Educ Pract Vet 1985;7:S69S78.

  • 14. Orsini JA, Divers TJ. Burns and acute swelling. In: Orsini JA, Divers TJ, eds. Manual of equine emergencies. 2nd ed. Philadelphia: WB Saunders Co, 2003;300304.

    • Search Google Scholar
    • Export Citation
  • 15. Owens CJ, Yarbrough DR III, Brackett NC Jr. Nephrotic syndrome following topically applied sulfadiazine silver therapy. Arch Intern Med 1974;134:332335.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16. Sawada Y. Adverse reaction to sulphonamides in a burned patient—a case report. Burns Incl Therm Inj 1985;12:127131.

  • 17. McKenna SR, Latenser BA, Jones LM, et al. Serious silver sulphadiazine and mafenide acetate dermatitis. Burns 1995;21:310312.

  • 18. Lockhart SP, Rushworth A, Azmy AA, et al. Topical silver sulphadiazine: side effects and urinary excretion. Burns Incl Therm Inj 1983;10:912.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 19. Eldad A, Neuman A, Weinberg A. Silver sulphadiazine-induced haemolytic anaemia in a glucose-6-phosphate dehydrogenase-deficient burn patient. Burns 1991;17:430432.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20. Maciel ABDS, Ortiz JF, Siqueira BS, et al. Tissue healing efficacy in burn patients treated with 1% silver sulfadiazine versus other treatments: a systematic review and meta-analysis of randomized controlled trials. An Bras Dermatol 2019;94:204210.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21. Nímia HH, Carvalho VF, Isaac C, et al. Comparative study of silver sulfadiazine with other materials for healing and infection prevention in burns: a systematic review and meta-analysis. Burns 2019;45:282292.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Boardman LA, Cooper AS, Blais LR, et al. Topical gabapentin in the treatment of localized and generalized vulvodynia. Obstet Gynecol 2008;112:579585.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23. Hiom S, Patel GK, Newcombe RG, et al. Severe postherpetic neuralgia and other neuropathic pain syndromes alleviated by topical gabapentin. Br J Dermatol 2015;173:300302.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24. Safaeian P, Mattie R, Hahn M, et al. Novel treatment of radicular pain with a multi-mechanistic combination topical agent: a case series and literature review. Anesth Pain Med 2016;6:e33322.

    • Search Google Scholar
    • Export Citation
  • 25. Derry S, Wiffen PJ, Kalso EA, et al. Topical analgesics for acute and chronic pain in adults—an overview of Cochrane Reviews. Cochrane Database Syst Rev 2017;5:CD008609.

    • Search Google Scholar
    • Export Citation
  • 26. Brutcher RE, Kurihara C, Bicket MC, et al. Compounded topical pain creams to treat localized chronic pain: a randomized controlled trial. Ann Intern Med 2019;170:309318.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27. Subrahmanyam M. A prospective randomized clinical and histological study of superficial burn wound healing with honey and silver sulfadiazine. Burns 1998; 24:157161.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28. Wijesinghe M, Weatherall M, Perrin K, et al. Honey in the treatment of burns: a systematic review and meta-analysis of its efficacy. N Z Med J 2009;122:4760.

    • Search Google Scholar
    • Export Citation
  • 29. Rieman MT, Neely AN, Boyce ST, et al. Amish burn ointment and burdock leaf dressings: assessments of antimicrobial and cytotoxic activities. J Burn Care Res 2014;35:e217e223.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30. Ollstein RN, McDonald C. Topical and systemic antimicrobial agents in burns. Ann Plast Surg 1980;5:386392.

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Clinical management and outcomes for goats, sheep, and pigs hospitalized for treatment of burn injuries sustained in wildfires: 28 cases (2006, 2015, and 2018)

Munashe Chigerwe1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Sarah M. Depenbrock1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Meera C. Heller1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Ailbhe King2William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Suzanne A. Clergue2William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Celeste M. Morris2William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Jamie L. Peyton3Integrative Medicine Service, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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John A. Angelos1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.

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Abstract

OBJECTIVE

To characterize injuries and describe medical management and clinical outcomes of goats, sheep, and pigs treated at a veterinary medical teaching hospital for burn injuries sustained during wildfires.

ANIMALS

Goats (n = 9), sheep (12), and pigs (7) that sustained burn injuries from wildfires.

PROCEDURES

Medical records were searched to identify goats, sheep, and pigs that had burn injuries associated with California wildfires in 2006, 2015, and 2018. Data regarding signalment, physical examination findings, treatments, clinical outcomes, time to discharge from the hospital, and reasons for death or euthanasia were recorded.

RESULTS

The eyes, ears, nose, mouth, hooves, perineum, and ventral aspect of the abdomen were most commonly affected in both goats and sheep. In pigs, the ventral aspect of the abdomen, distal limb extremities, ears, and tail were most commonly affected. The median (range) time to discharge from the hospital for goats and pigs was 11 (3 to 90) and 85.5 (54 to 117) days, respectively. One of 9 goats, 12 of 12 sheep, and 5 of 7 pigs died or were euthanized. Laminitis and devitalization of distal limb extremities were common complications (13/28 animals) and a common reason for considering euthanasia in sheep and pigs.

CONCLUSIONS AND CLINICAL RELEVANCE

Burn injuries in small ruminants and pigs required prolonged treatment in some cases. Results suggested prognosis for survival may be more guarded for sheep and pigs with burn injuries than for goats; however, further research is needed to confirm these findings.

Abstract

OBJECTIVE

To characterize injuries and describe medical management and clinical outcomes of goats, sheep, and pigs treated at a veterinary medical teaching hospital for burn injuries sustained during wildfires.

ANIMALS

Goats (n = 9), sheep (12), and pigs (7) that sustained burn injuries from wildfires.

PROCEDURES

Medical records were searched to identify goats, sheep, and pigs that had burn injuries associated with California wildfires in 2006, 2015, and 2018. Data regarding signalment, physical examination findings, treatments, clinical outcomes, time to discharge from the hospital, and reasons for death or euthanasia were recorded.

RESULTS

The eyes, ears, nose, mouth, hooves, perineum, and ventral aspect of the abdomen were most commonly affected in both goats and sheep. In pigs, the ventral aspect of the abdomen, distal limb extremities, ears, and tail were most commonly affected. The median (range) time to discharge from the hospital for goats and pigs was 11 (3 to 90) and 85.5 (54 to 117) days, respectively. One of 9 goats, 12 of 12 sheep, and 5 of 7 pigs died or were euthanized. Laminitis and devitalization of distal limb extremities were common complications (13/28 animals) and a common reason for considering euthanasia in sheep and pigs.

CONCLUSIONS AND CLINICAL RELEVANCE

Burn injuries in small ruminants and pigs required prolonged treatment in some cases. Results suggested prognosis for survival may be more guarded for sheep and pigs with burn injuries than for goats; however, further research is needed to confirm these findings.

California frequently experiences devastating wildfires that result in loss of human and animal life, destruction of property, displacement of residents from affected areas, negative impact on air quality, changes in ecosystems, and financial losses.1 Wildfires result from arson, dry lightning strikes, problems with power lines, or other sources such as campfires, but the cause can remain unknown in some cases.1 Risk factors for the occurrence and spread of wildfires in California include prolonged dry weather conditions from spring to fall, low humidity, and presence of strong winds.2

In wildfire emergencies, veterinary care for burn injuries of domestic animals might be performed efficiently in the field or in temporary shelters.3 However, animals with severe burns require intensive management in a hospital setting to improve survival and pain control. Recently, the California Veterinary Medical Reserve Corps updated their canine, feline, and equine burn-care protocols,4 and additional information on the care of small ruminants and pigs with these injuries will add to the body of knowledge on management of burns in other animal species. Therefore, observational studies describing clinical outcomes of hospitalized livestock with burn injuries from wildfires are warranted. The objective of the study reported here was to characterize injuries and describe medical management and clinical outcomes of goats, sheep, and pigs treated at a VMTH for burn injuries sustained during wildfires.

Materials and Methods

Case selection criteria

Computerized medical records of the University of California-Davis VMTH were electronically searched to identify goats, sheep, and pigs that were treated for burn injuries from wildfires in 2006, 2015, and 2018. The wildfires in 2006, 2015, and 2018 occurred close to or within the VMTH practice area, thereby allowing patient admissions. Keywords in electronic searches included forest, fire, wildfire, burn, caprine, ovine, and porcine.

Medical records review

The information on age, breed, and use of animals was limited. Information on age (when available) and sex, physical examination findings associated with the burn wounds, and medical and surgical procedures performed were recorded. Burns were classified during clinical examination on the basis of depth and body surface area involved, consistent with classifications used for dogs,5 cats,5 and horses.6 First-degree burns were superficial and involved the outermost layer of the epidermis. Second-degree burns were partial thickness and involved the epidermis and portions of the dermis. Third-degree burns were full thickness and involved loss of epidermis and dermis. Fourth-degree burns involved underlying muscles, bone, ligaments, fat, and fascia. Clinical outcomes, including time to discharge from the hospital, death, or euthanasia, were recorded.

Medical and surgical management

For goats and sheep, medical procedures such as IV catheter placement and surgical debridement were performed with the patient under sedation or general anesthesia. These animals were sedated with xylazine hydrochloridea or detomidine hydrochlorideb (0.01 to 0.05 mg/kg [0.005 to 0.023 mg/lb], IV) alone or with midazolamc (0.2 to 0.4 mg/kg [0.09 to 0.18 mg/lb], IV), followed by induction and maintenance of general anesthesia with isofluraned (to effect) when applicable. For pigs, medical and surgical procedures were performed after administration of either tiletamine-zolazepame (2 to 4 mg/kg, IM) alone or with midazolam (0.2 to 0.4 mg/kg, IM), followed by induction and maintenance of general anesthesia with isoflurane (to effect) when applicable. Use of sedation alone or sedation followed by general anesthesia was determined on the basis of severity of the burns as assessed during clinical examination. When deemed necessary, a CBC and serum biochemical analysis were performed at the time of admission, during hospitalization, or both to assess organ function or monitor systemic response to treatment. Thoracic radiography was performed to assess whether pneumonia associated with smoke inhalation was present in patients with respiratory distress at the time of admission.

When present, hair or wool around the burn lesions was clipped. Prior to debridement of the lesions, fire decontamination body wipesf were used to remove soot. Wounds were debrided with sterile gauze, a scalpel blade, or both; rinsed with warm saline (0.9% NaCl) or dilute betadine (approx 1:100 [vol:vol] in saline) solution; and dried with sterile gauze. Management of patients after wound debridement depended on the type of topical medications available at the VMTH at the time of treatment. For animals treated in 2006 and 2015, 1% silver sulfadiazine creamg alone or in combination with zinc oxideh was applied topically every 12 hours. For animals treated in 2018, drying of lesions was followed by application of a topical wound spray.i After the topical wound spray dried, a compounded topical gelj formulated for pain relief (ie, burn wound gel) containing a mixture of gabapentin (11.8%), lidocaine (0.67%), prilocaine (0.67%), diclofenac (0.89%), and ketamine (1.8%) was applied every 12 to 24 hours on lesions, except those around the eyes, nose, ears, and mouth for all species. For areas around the eyes, nose, ears, and mouth, the topical wound spray application was followed by topical application of a compounded cream (manuka honey wax salve) containing beeswax, coconut oil, and aloe verak every 12 hours. When burns affected the eyelids or eye globe, either of 2 topical ophthalmic ointmentsl,m was applied every 12 to 24 hours. On a case-by-case basis in 2018, burned skin was treated with 1% silver sulfadiazine cream and burn wound gel with or without manuka honey wax salve. Debridement and application of topical medication continued until patients were discharged from the hospital. Depending on the severity and location of injuries, dressing of wounds with sterile gauze bandaging was performed on a case-by-case basis.

Crystalloid fluids with added amino acids, dextrose, or vitamins; a colloid solution (plasma); or both were administered IV in all species when deemed necessary. Nonsteroidal anti-inflammatory drugs administered included flunixin megluminen (0.5 to 1.1 mg/kg [0.23 to 0.5 mg/lb], q 12 to 24 hours) administered IV for goats and sheep and IM for pigs, meloxicamo (0.5 mg/kg, PO, q 24 h), for all species, or carprofenp (2.2 mg/kg [1 mg/lb], PO, q 12 h) for pigs. Opioids used to manage pain included morphineq (0.1 to 0.4 mg/kg [0.045 to 0.18 mg/lb], IM or IV, q 4 to 12 hours), fentanylr (transdermal patch formulated to release 25 μg/h; replaced q 48 to 72 hours), or hydromorphones (0.01 mg/kg [0.0045 mg/lb], IV, q 4 to 12 hours). Gabapentint (5 to 10 mg/kg [2.3 to 4.5 mg/lb], PO, q 8 to 12 hours) was administered for all species when neurogenic pain was suspected or evident. Analgesics were administered as an NSAID alone, an opioid alone, a combination of an NSAID and opioid, or a combination of an NSAID, an opioid, and gabapentin. Decisions to administer analgesics individually or as combinations were made on the basis of findings for assessment of kidney function through serum biochemical analysis, ability to establish peripheral venous access, and subjective assessment of the degree of pain experienced by the patient.

Classes of antimicrobials administered for treatment or prophylaxis at the recommended dosages included macrolides (tulathromycin), tetracyclines (oxytetracycline), phenicols (florfenicol), penicillin-β lactamase inhibitors (amoxicillin–clavulanic acid), and cephalosporins (ceftiofur). Other medications administered on a case-by-case basis included thiamine hydrochlorideu (10 mg/kg, IV or IM, q 4 to 12 hours), famotidine hydrochloridev (0.4 mg/kg, IV, q 4 to 8 hours), vitamin Ew (40 U/kg [18 U/lb], PO, q 24 h) or a vitamin E–selenium combinationx (1 mL/22.5 kg [1 mL/49.5 lb], IM, once), and tetanus antitoxiny (1,500 U/animal, IM, once). There was extralabel use of the topical gels and some antimicrobials, and meat withdrawal time recommendations were requested from the Food Animal Residue Avoidance Data Bank.7

Data analysis

Descriptive statistics for age, sex, breed, and classification of burns were determined for goats, sheep, and pigs. Clinical examination findings and medical and surgical procedures performed were summarized, and the proportions of patients that developed complications, survived to hospital discharge, died, or were euthanized during management were calculated for each species.

Results

Goats, sheep, and pigs that sustained burn injuries from wildfires were presented to the VMTH by owners, volunteers, fire department personnel, or members of law enforcement agencies. Nine goats (2 in 2015 and 7 in 2018), 12 sheep (11 in 2006 and 1 in 2018), and 7 pigs (2 in 2015 and 5 in 2018) met the study inclusion criteria.

The median age of goats was 4 years (range, 3 months to 10 years) at admission. The ages of sheep at admission were unknown or not recorded, but all sheep were considered ≥ 2 years old on the basis of dental examination. The ages of pigs at admission were not reported, except for 1 patient that was 6 months of age. Six of 9 goats were males, and 3 were females. One of 12 sheep were males, and 11 were females. One of 7 pigs were males, and 6 were females. Breed was reported for 8 of 9 goats and included Boer (n = 2), Nubian (2), Alpine (2), Nigerian Dwarf (1), and Tennessee Fainting Goat (1). Eleven sheep were Suffolk or Suffolk crosses, and breed was not reported for the remaining sheep. There were 3 Vietnamese potbellied pigs, 1 Duroc, and 1 Poland China; breed was not reported for the remaining 2 pigs. Eleven sheep were raised as production animals; all goats and pigs and the remaining sheep were considered pets.

Clinical examination findings and procedures

Most patients (5/9 goats, 12/12 sheep, and 7/7 pigs) had third-degree burns. Second-degree burns were sustained by 6 animals (4 goats and 2 pigs). First-degree and fourth-degree burns were identified in 2 goats and 2 pigs, respectively. Five patients (2 goats and 3 pigs) had burns of > 1 classification. The most commonly affected body regions in goats and sheep were the head (eyes, ears, nose, mouth, or a combination of these sites; 18/21 animals), the hooves (13), the perineum (6), and the ventral aspect of the abdomen (5). Additionally, the udder was commonly affected in sheep (n = 2). In pigs, the most commonly affected body regions were the ventral aspect of the abdomen (5/7), distal limb extremities (5), ears (2/7 animals), and tail (2). Laminitis was diagnosed in 13 animals (10 sheep and 3 pigs).

In addition to burns, 2 sheep and 1 pig had signs of respiratory distress, presumably as a result of smoke inhalation, at the time of admission. Radiographic findings for the 2 sheep included peracute diffuse, interstitial, intra-alveolar, and interlobular edema. Radiographic findings for the pig included acute moderate, interstitial pneumonia with regional inflation.

Complete blood counts were performed for 3 goats, and clinically relevant abnormalities included leukocytosis (n = 3) and hyperfibrinogenemia (1). Results were within the respective reference ranges for 2 of 2 pigs that had CBCs performed. Serum biochemical analysis was performed for 4 goats, 5 sheep, and 4 pigs; results were within the respective reference ranges for all goats, whereas various abnormalities were found in sheep (hyperglycemia [n = 1], hypoglycemia [1], hypokalemia [5], hypoalbuminemia [4], mild hyperchloremia [5], and high creatine kinase activity [1]) and pigs (hypoglycemia [n = 2], mild hypophosphatemia [1], and high creatine kinase activity [2]).

Analgesics were administered parenterally to all patients. Four of 9 goats, 3 of 12 sheep, and 0 of 7 pigs were administered IV fluids. Eight of 9, 10 of 12, and 7 of 7 goats, sheep, and pigs, respectively, received parenteral antimicrobial treatment. Antimicrobials administered to goats and sheep included ceftiofur, florfenicol, tulathromycin, and oxytetracycline. Antimicrobials administered to pigs included ceftiofur, florfenicol, tulathromycin, and amoxicillin–clavulanic acid. Silver sulfadiazine was applied topically to the burn wounds in 5 of 9 goats, 8 of 12 sheep, and 5 of 7 pigs. Of topically applied treatments available only in 2018, the wound spray was used for 2 of 7 goats and 5 of 5 pigs treated at the VMTH in that year; the burn wound gel was used for 3 goats and 5 pigs; and the manuka honey wax salve was used for 2 goats and 3 pigs. Zinc oxide was used for 1 goat, 3 sheep, and 2 pigs.

Clinical outcomes

Proportions of goats, sheep, and pigs that died or were euthanized were 1 of 9, 12 of 12, and 5 of 7, respectively. The median time to discharge from the hospital for surviving goats and pigs was 11 days (range, 3 to 90 days [n = 8]), and 85.5 days (range, 54 to 117 days [2]), respectively. Median time to euthanasia or death for sheep and pigs was 6.5 days (range, 1 to 20 days [12]), and 13 days (range, 1 to 25 days [5]), respectively. The goat was euthanized 14 days after admission because of seizures that were nonresponsive to treatment with IV fluid administration, analgesics, thiamine, and vitamin E with selenium. Eleven sheep were euthanized, and 1 died; 3 pigs were euthanized, and 2 died. Reasons for euthanasia of sheep included severe laminitis characterized by coronary band separation and sloughing of the hoof wall (n = 10), and obtundation with bilateral blindness (1). Death in 1 sheep was caused by complications associated with septicemia. The 3 pigs were euthanized because of burn-induced septic arthritis with exposure or complete devitalization and sloughing of distal extremities including the third phalanx, and death for the 2 pigs that died was attributed to complications from septicemia (n = 1) and seizures (1).

A semipermanent rumenostomy was performed in 1 goat to aid feeding. A bilateral pinnectomy was performed in 1 goat because of severe aural burns. The same goat that underwent pinnectomy developed urolithiasis while hospitalized, and this condition was managed successfully with tube cystostomy. Five sheep were pregnant, and emergency cesarean sections were performed for 4 of these 5 animals because of deteriorating clinical condition. All lambs (4 pairs of twins) delivered by cesarean section died or were euthanized because of prematurity.

Necropsy results were available for 10 of 12 sheep and 3 of 5 pigs. Consistent pathological findings in sheep included severe extensive epidermal and dermal necrosis of the skin with eschar formation (ie, scab of dead tissue shedding off from healthy tissue) and severe laminitis with coronary band separation and sloughing of the hoof wall. The 2 sheep with signs of respiratory distress had severe interstitial pneumonia. Consistent pathological findings in pigs included eschar formation and full-thickness necrosis of skin on the limbs and ventral abdomen. Additionally, one of the pigs had interstitial pneumonia, another had fibrinosuppurative pneumonia with intralesional bacteria, and another had pulmonary edema and encephalitis diagnosed.

Discussion

In the study reported here, mortality rates associated with complications from wildfire burn wounds were relatively high in sheep and pigs, compared with the outcomes for goats. The most common reason for considering euthanasia of sheep and pigs in our study sample was severe damage to the distal aspects of limbs. The likely reason for the high mortality rate in sheep in our study was the relatively higher frequency of third-degree burns at admission. It is important to note that the burn classifications could potentially change during management, for instance, burns classified as third degree could progress to fourth degree, thereby negatively impacting the patient's prognosis.

Several anecdotal reasons might potentially explain the differences in severity of burn wounds for the 3 species in this study. The sheep in our study were all from large flocks raised for meat production, and it was likely that there were delays in restraint, medical management in the field, or transport to the hospital. Burning wool may also have exacerbated the intensity and transfer of heat to the skin in sheep, resulting in more severe burns. The presence of substantial amounts of subcutaneous fat in pigs might aid transfer of heat to underlying tissues resulting in more severe injury. Furthermore, severe burn injuries to the ventrum of pigs could have resulted from their low body carriage exposing the ventrum and the relatively short limbs being in contact with hot coals or flames when moving through burning pastures. Research in laboratory mice and examination of samples from human patients indicate that changes in adipose tissue are associated with a hypermetabolic state following burn injury, which in turn is associated with higher morbidity and mortality rates in patients recovering from burn injuries.8 Thus, it is possible that the greater body fat in pigs might also increase their risk for severe illness and death.

The hypermetabolic state in patients with burn injuries is characterized by increased caloric expenditure, protein catabolism, and increased glucose consumption.9–11 Thus, provision of parenteral nutrition by IV fluid administration or enteral feeding via rumenostomy when burn injuries preclude prehension, as was determined for some patients in our study, are warranted to prevent severe weight loss. In horses being managed for burn injuries, weight loss > 10% to 15% of body weight indicates insufficient nutritional intake.6 Although there are no comparable recommendations in small ruminants or pigs, the guidance for determining insufficient nutrition in horses might be applicable to goats, sheep, and pigs. Alternatively, monitoring of body condition scores should be considered to assess for weight loss during management of small ruminants and pigs recovering from burn injuries. Gradual increases in the quantity of grain and highly digestible forages such as alfalfa have been recommended to improve caloric intake in horses.6 These dietary recommendations might also be applicable to goats and sheep (grain and alfalfa) and pigs (grain) recovering from burn injuries.

Silver sulfadiazine cream was the only topical antimicrobial used in our study. The product penetrates eschars and is active against bacteria likely to contaminate burn wounds, including Pseudomonas spp, Staphylococcus aureus, and Enterobacteriaceae, including Escherichia coli and Proteus spp.12–14 Silver sulfadiazine causes minimal pain on application, but it is inactivated by tissue secretions and must be applied twice daily.6 However, it should be noted that application of topical medications and placement of bandaging every 12 hours might not be feasible for patients (such as pigs) that require sedation or general anesthesia for wound debridement. Topical application of silver sulfadiazine has been reported to have minimal systemic effects in horses13,14; however, several adverse effects, including skin hypersensitivity, hemolysis, formation of immune complexes, and methemoglobinemia have been reported in human patients.15–19 Although, to our knowledge, no comparable reports are available for small ruminants and pigs, we found no indication of any of the reported adverse effects in the medical records for patients in our study. It should be noted that the number of animals in this study was small; also, topical application of silver sulfadiazine constituted an extralabel use of the antimicrobial in pigs in the present study. Extralabel use of this and other sulfonamides is restricted in major food-producing species (prohibited in some cases) and is discouraged but not prohibited in minor food-producing species (eg, goats and sheep) in the United States.7 Results of recent meta-analyses of human clinical trials20,21 indicate that silver sulfadiazine is associated with delayed wound healing and increased rates of infection, compared with other topical treatments such as honey, hydrocolloids, and aloe vera. Comparison of silver sulfadiazine with other topical treatments was beyond the scope of our retrospective study, but the findings reported for human patients should be considered in treatment of burn wounds after debridement for veterinary patients.

Compounded combination topical pain-relieving formulations such as the burn wound gel used in our study have been considered as alternative treatments for human patients with neuropathic pain to reduce the incidence of adverse effects associated with NSAID use or opioid dependence, but the study outcomes have been variable. Some reports described benefits for patients treated for localized chronic pain with topical creams containing gabapentin22,23 or a multimechanistic combination of topical agents,24 but other studies25,26 reported no benefits from their use, compared with placebos. To our knowledge, no comparable studies of such treatments for large animals are available, and we did not find evidence of adverse effects from potential systemic absorption of the burn wound gel used in animals of the present study in 2018. However, this should be interpreted cautiously because of the small number of treated animals for each species. Also, the application of this topical gel constituted extralabel drug use, and its cost was relatively high. Further studies are warranted to determine whether the use of such products is beneficial. Anecdotally, attending veterinarians who administered the compounded burn wound gel in our study reported subjectively improved local pain control at the wound sites in patients. Some of the patients in the last year of this retrospective study had manuka honey wax salve applied to burn injuries on the basis of reports27,28 for human patients indicating that such products promote healing of burn injuries, results attributed to potential anti-inflammatory and antimicrobial effects. However, results of an in vitro study29 showed that reconstituted extracts from 1 topical burn wound dressing containing honey wax had no antimicrobial activity but inhibited growth of keratinocytes and fibroblasts and had potential cytotoxic effects, suggesting a negative impact on wound healing.

Short-term parenteral administration of antimicrobials is recommended during the immediate postburn period when quantitative tissue biopsy cultures yield > 10,000 cells/g.30 Biopsies were not performed for the animals described in the present study, but these patients received parenteral antimicrobial treatment because the attending veterinarians considered them to have an increased risk for secondary bacterial infections and development of septicemia. The choice of antimicrobials administered in our study was made on the basis of the antimicrobial spectrum, patient organ function as assessed by clinical examination and hematologic or biochemical test results, severity and contamination of the wounds, and clinician preference. Parenteral antimicrobial administration in these patients contrasted with an anecdotal report6 that indicates systemic antimicrobial treatments do not favorably influence rates of wound healing, fever, or death, and might encourage the emergence of resistant microorganisms. Furthermore, blood circulation to the burned areas is often compromised, making it unlikely that parenterally administered antimicrobials can reach therapeutic concentrations at the wound sites.6

Thiamine was administered to goats and sheep to prevent cerebrocortical necrosis (polioencephalomalacia) due to decreased feed intake (and thus decreased thiamine synthesis from rumen microbes) resulting from pain associated with burn wounds around the lips. Famotidine hydrochloride was administered to prevent abomasal or gastric ulceration secondary to stress likely to be associated with pain and hospitalization. Vitamin E and selenium were administered for their antioxidant properties, whereas zinc oxide ointment was applied as a barrier on burn wounds to prevent additional skin irritation.

Although wildfires are more common in California, compared with other regions in the United States, our study results provided practical clinical information applicable to goats, sheep and pigs in California and other regions that might experience wildfires. It is important to note that wildfires might also result in destruction of veterinary practices, and thus, veterinarians from private and academic practices in surrounding unaffected areas might be asked to manage animals surviving wildfires from their geographic region.

Limitations of the study reported here included a small sample size; the retrospective, records-based nature of the study; and limited external validity of the study results. It was likely that sheep and pigs referred to the VMTH were the most severely affected for which treatment was sought, resulting in high mortality rates. In our study, the time from admission to hospital discharge was unreliable because some patients were hospitalized longer than necessary to allow time to identify the owner or for the owner to find temporary shelter for the animals. The cost for managing each patient was relatively high, but financial assistance was provided by the VMTH, private donors, and state emergency agencies. Thus, in clinical practice, the costs of some medical and surgical procedures for small ruminants or pigs with burn injuries may be a limiting factor if financial assistance is not available.

The anatomic regions commonly affected in goats and sheep that sustained burn injuries in wildfires included the eyes, ears, nose, mouth, ventral aspect of the abdomen, perineum, and hooves, with the udder commonly affected in sheep as well. In pigs, the ears, ventral aspect of the abdomen, distal limb extremities, and tail were commonly affected. Our study results suggested that treatment of patients with burn wounds from wildfires can be prolonged. Laminitis characterized by separation of the hoof wall was a common complication in the study sample (identified in 13/28 [46%] animals) and a common reason for euthanasia of sheep. Burns causing devitalization of entire distal limb extremities including phalangeal bones were a common reason for euthanasia of swine. The results suggested that prognosis for survival of burn injuries may be more guarded for sheep and pigs than for goats, however, further research is needed to confirm these findings. Veterinarians should encourage livestock owners to develop evacuation plans and be prepared for fire events during times of the year when risks for wildfires are greatest.

Acknowledgments

No third-party funding or support was received in connection with this study or the writing or publication of the manuscript. The authors declare that there were no conflicts of interest.

ABBREVIATIONS

VMTH

Veterinary medical teaching hospital

Footnotes

a.

AnaSed, Akorn Animal Health, Lake Forest, Ill.

b.

Dormosedan, Zoetis, Parsippany, NJ.

c.

Akorn Animal Health, Lake Forest, Ill.

d.

Isoflurane, Piramal Healthcare, Bethlehem, Pa.

e.

Telazol, Zoetis Inc, Kalamazoo, Mich.

f.

Hero Wipes Fire, Diamond Wipes International Inc, Chino, Calif.

g.

Silvadene cream 1%, King Pharmaceuticals Inc, Bristol, Tenn.

h.

Desitin, Johnson & Johnson Inc, NB, NJ.

i.

Microcyn Animal Health Wound and skin care, Oculus Innovative Sciences, Petaluma, Calif.

j.

Burn gel, UC Davis VMTH Pharmacy, Davis, Calif.

k.

Honey wax salve, UC Davis VMTH Pharmacy, Davis, Calif.

l.

Microcyn Animal Health ophthalmic gel, Oculus Innovative Sciences, Petaluma, Calif.

m.

Terramycin Ophthalmic Ointment, Zoetis, Kalamazoo, Mich.

n.

Banamine, Merck Animal Health, Madison, NJ.

o.

Unichem Pharmaceuticals, Rochelle Park, NJ.

p.

Rimadyl, Zoetis, Kalamazoo, Mich.

q.

West-Ward Pharmaceuticals, Eatontown, NJ.

r.

Fentanyl transdermal system, 25 μg/h, Mallinckrodt Pharmaceuticals, Mountain View, Calif.

s.

West-Ward Pharmaceuticals, Eatontown, NJ.

t.

Actavis, Parsippany-Troy Hills, NJ.

u.

Vedco Inc, St Joseph, Mo.

v.

West-Ward Pharmaceutical, Eatontown, NJ.

w.

Emcelle Tocopherol, Stuart Products, Bedford, Tex.

x.

Bo-Se, Merck Animal Health, Madison, NJ.

y.

Tetanus antitoxin, Colorado Serum Co, Denver, Colo.

References

  • 1. California Department of Forestry and Fire Protection. Stats and Events. Available at: www.fire.ca.gov/. Accessed Oct 18, 2019.

  • 2. Duclos P, Sanderson LM, Lipset M. The 1987 forest fires disaster in California: assessment of emergency room visits. Arch Environ Health 1990;45:5358.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Madigan JE, Rowe JD, Angelos JA, et al. Wildlife associated burn injury of 1400 sheep in Northern California: a coordinated mass casualty veterinary response. Prehosp Disaster Med 2011;26 (suppl 1):S90S91.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. California Veterinary Medical Association. California Veterinary Medical Reserve Corps (CAVMRC) volunteer handbook. Sacramento: California Veterinary Medical Association, 2019. Available at: cvma.net/resources/disaster-response-program-2/california-veterinary-medical-reservecorps-cavmrc/california-veterinary-medical-corps-cavmrc-information/. Accessed May 18, 2020.

    • Search Google Scholar
    • Export Citation
  • 5. Pavletic MM, Trout NJ. Bullet, bite, and burn wounds in dogs and cats. Vet Clin North Am Small Anim Pract 2006;36:873893.

  • 6. Hanson RR. Management of burn injuries in the horse. Vet Clin North Am Equine Pract 2005;21:105123.

  • 7. Food Animal Residue Avoidance Data Bank. Prohibited and restricted drugs in food animals. Available at: farad.org/prohibited-and-restricted-drugs.html. Accessed Sep 30, 2019.

    • Search Google Scholar
    • Export Citation
  • 8. Patsouris D, Qi P, Abdullahi A, et al. Burn induces browning of the subcutaneous white adipose tissue in mice and humans. Cell Rep 2015;13:15381544.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9. Wilmore DW, Long JM, Mason AD Jr, et al. Catecholamines: mediator of the hypermetabolic response to thermal injury. Ann Surg 1974;180:653669.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 10. Herndon DN, Wilmore DW, Mason AD Jr. Development and analysis of a small animal model simulating the human postburn hypermetabolic response. J Surg Res 1978;25:394403.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 11. Herndon DN, Curreri PW, Abston S, et al. Treatment of burns. Curr Probl Surg 1987; 24:341397.

  • 12. Fox SM. Management of thermal burns, part 1. Compend Contin Educ Pract Vet 1985;7:631642.

  • 13. Geiser D, Walker RD. Management of large animal thermal injuries. Compend Contin Educ Pract Vet 1985;7:S69S78.

  • 14. Orsini JA, Divers TJ. Burns and acute swelling. In: Orsini JA, Divers TJ, eds. Manual of equine emergencies. 2nd ed. Philadelphia: WB Saunders Co, 2003;300304.

    • Search Google Scholar
    • Export Citation
  • 15. Owens CJ, Yarbrough DR III, Brackett NC Jr. Nephrotic syndrome following topically applied sulfadiazine silver therapy. Arch Intern Med 1974;134:332335.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16. Sawada Y. Adverse reaction to sulphonamides in a burned patient—a case report. Burns Incl Therm Inj 1985;12:127131.

  • 17. McKenna SR, Latenser BA, Jones LM, et al. Serious silver sulphadiazine and mafenide acetate dermatitis. Burns 1995;21:310312.

  • 18. Lockhart SP, Rushworth A, Azmy AA, et al. Topical silver sulphadiazine: side effects and urinary excretion. Burns Incl Therm Inj 1983;10:912.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 19. Eldad A, Neuman A, Weinberg A. Silver sulphadiazine-induced haemolytic anaemia in a glucose-6-phosphate dehydrogenase-deficient burn patient. Burns 1991;17:430432.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20. Maciel ABDS, Ortiz JF, Siqueira BS, et al. Tissue healing efficacy in burn patients treated with 1% silver sulfadiazine versus other treatments: a systematic review and meta-analysis of randomized controlled trials. An Bras Dermatol 2019;94:204210.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 21. Nímia HH, Carvalho VF, Isaac C, et al. Comparative study of silver sulfadiazine with other materials for healing and infection prevention in burns: a systematic review and meta-analysis. Burns 2019;45:282292.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22. Boardman LA, Cooper AS, Blais LR, et al. Topical gabapentin in the treatment of localized and generalized vulvodynia. Obstet Gynecol 2008;112:579585.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 23. Hiom S, Patel GK, Newcombe RG, et al. Severe postherpetic neuralgia and other neuropathic pain syndromes alleviated by topical gabapentin. Br J Dermatol 2015;173:300302.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24. Safaeian P, Mattie R, Hahn M, et al. Novel treatment of radicular pain with a multi-mechanistic combination topical agent: a case series and literature review. Anesth Pain Med 2016;6:e33322.

    • Search Google Scholar
    • Export Citation
  • 25. Derry S, Wiffen PJ, Kalso EA, et al. Topical analgesics for acute and chronic pain in adults—an overview of Cochrane Reviews. Cochrane Database Syst Rev 2017;5:CD008609.

    • Search Google Scholar
    • Export Citation
  • 26. Brutcher RE, Kurihara C, Bicket MC, et al. Compounded topical pain creams to treat localized chronic pain: a randomized controlled trial. Ann Intern Med 2019;170:309318.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 27. Subrahmanyam M. A prospective randomized clinical and histological study of superficial burn wound healing with honey and silver sulfadiazine. Burns 1998; 24:157161.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28. Wijesinghe M, Weatherall M, Perrin K, et al. Honey in the treatment of burns: a systematic review and meta-analysis of its efficacy. N Z Med J 2009;122:4760.

    • Search Google Scholar
    • Export Citation
  • 29. Rieman MT, Neely AN, Boyce ST, et al. Amish burn ointment and burdock leaf dressings: assessments of antimicrobial and cytotoxic activities. J Burn Care Res 2014;35:e217e223.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 30. Ollstein RN, McDonald C. Topical and systemic antimicrobial agents in burns. Ann Plast Surg 1980;5:386392.

Contributor Notes

Address correspondence to Dr. Chigerwe (mchigerwe@ucdavis.edu).