United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Veterinary Services 

Centers for Epidemiology and Animal Health August 2012 

_________________________________________________________________________________________________________________________ 

Risk Factors Associated with 

Clostridial Dermatitis on U.S. 

Turkey-grower Farms 

Introduction 

A disease of turkeys and broilers, clostridial dermatitis 

(cellulitis/gangrenous dermatitis) has become an issue of 

concern in recent years. In 2010, the U.S. Animal 

Health Association (USAHA) ranked clostridial dermatitis 

among the top three disease issues in turkeys (USAHA, 

2010). The disease causes mortality with necrosis, 

edema, and/or gas in the subcutaneous tissues, and 

most often affects toms 13 to 18 weeks old. 

 In December 2008, a Gold Medal Panel of industry 

experts was assembled to identify research needs and 

discuss clostridial dermatitis. Several measures to 

control or stop the disease were discussed: 

 Removing dead birds from barns at least two to 

three times per day, 

 Keeping litter dry, 

 Feeding probiotics/direct-fed microbials, 

 Barn cleanout including litter removal after an 

affected flock, 

 Acidifying litter, 

 Acidifying birds’ drinking water, 

 Adding iodine to birds’ drinking water, 

 In-barn composting of litter between flocks (windrow 

composting), 

 Minimizing bird stress, 

 Adding extra vitamin E to feed, and 

 Increasing barn space allocated for birds 

(decreased stocking density) (Clark, 2010). 

 Most of these measures are aimed at decreasing the 

bacterial load in the barn and/or changing environmental 

conditions to be less favorable for clostridial growth. 

Methodology

 The U.S. Department of Agriculture’s National 

Animal Health Monitoring System (NAHMS) conducted a 

study to determine risk factors associated with clostridial 

dermatitis on U.S. turkey farms. For the study, 15 of the 

Nation’s largest turkey companies were selected to 

participate. The selected companies represented 76.8 

percent of turkeys slaughtered in the United States in 

2009 (WATT, 2010). Ten of the 15 selected companies 

agreed to participate in the study. 

 Participating companies selected case and control 

farms based on the following definitions provided by 

NAHMS: 

 Case farm: farm in which at least two-thirds of flocks 

placed were affected with clostridial dermatitis during 

the previous 12 months. An affected flock was one 

in which mortality due to clostridial dermatitis was 

greater than 0.5 per 1,000 birds for 2 consecutive 

days. 

 Control farm: farm with little or no problem with 

clostridial dermatitis during the previous 12 months. 

 Questionnaires were completed for 36 case farms 

and 35 control farms between June 3 and December 17, 

2010. Questionnaire data were analyzed to look for 

statistical associations between farm status (case vs. 

control) and farm characteristics, such as management 

practices. 

Results 

 Risk factors found to be associated 

(p-value <0.05) with clostridial dermatitis included: 

 Composting litter within 200 feet of a poultry barn, 

 Soil pH immediately outside of barn of 6.0 or 

higher, and

 Humidity level 60 percent or higher in the barn 

(figure 1, table 1). 

 

 In addition, requiring employees to scrub footwear 

was associated with a reduced risk of clostridial 

dermatitis. The questionnaire did not collect information 

on in-barn windrow composting of litter, only on litter 

composting that occurred in a location outside the 

poultry barns. 

Technical Brief
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Table 1. Results of logistic regression for factors 

associated with being a clostridial dermatitis case 

farm 

Factor Odds ratio p-value 

Litter composted within 

200 ft of poultry barn1 8.3 0.01 

Employees required to scrub 

footwear (bucket and brush)1 0.09 0.0004 

Soil pH ≥6.02 17.5 0.02 

Humidity ≥60 percent2 11.6 0.02 

1

Adjusted for region. 

2

Adjusted for region and season.

 Case farms were less likely to require employees to 

scrub footwear compared with control farms (OR=0.09; 

table 1). This finding suggests that clostridial organisms 

from other locations on the farm might be transported 

and introduced to the poultry barn by employee 

footwear. Most of the farms that did not require 

employees to scrub footwear used a different footwear 

precaution, such as dry or liquid footbaths. Scrubbing 

footwear with a bucket and brush, and thereby reducing 

microbial contamination from boots, might be more 

effective than dry or wet footbaths. Based on this study, 

scrubbing footwear is recommended to help prevent or 

control clostridial dermatitis. 

 Litter management is thought to be an important 

component of clostridial dermatitis control. This study 

found that case farms were more likely than control 

farms to compost litter within 200 feet of poultry barns 

(OR=8.3; table 1). Control farms were more likely to 

compost litter more than 200 feet from poultry barns or 

not compost litter at all. The proximity of the composting 

shed to the poultry barns was the important factor, not 

whether litter was composted on site. 

 It is unclear why having a composting shed in close 

proximity to the poultry barns is associated with being a 

case farm. Clostridium septicum is thought to be the 

principal cause of clostridial dermatitis (Tellez, 2009). 

Litter from an affected flock is likely to have a high 

number of C. septicum spores. Some farms also 

compost dead birds along with litter, which may increase 

the clostridial load. In theory, C. septicum could be 

carried mechanically from the composting shed to the 

poultry barns by people, rodents, or insects. Airborne 

spread of some clostridial species has also been 

reported (Pillai et al., 1996; Chai et al, 1997; Best et al., 

2010; Keessen et al., 2011). C. septicum could be 

disseminated by airborne routes as well, but further 

research is needed to determine how far spores can 

travel when airborne. 

 Case farms had significantly higher humidity levels 

in the poultry barns and higher soil pH than control farms 

(figure 1). Perhaps the association between high 

humidity and clostridial dermatitis is related to increased 

litter moisture. However, litter moisture was not 

measured in this study. Higher soil pH (≥6) may be 

favorable to clostridial organisms since they prefer a pH 

of 6 to 7 for optimal growth and toxin production. 

 Certain factors believed to be important to clostridial 

dermatitis control were not found to have a statistically 

significant association with farm status (case vs. control) 

in this study. For example, the following variables were 

analyzed but not found to be statistically significant: 

• Frequency of mortality removal 

• Use of a cull pen 

• Barn cleanout practices 

• Litter tilling 

• Dead bird disposal by composting. 

 

 If case farms changed their practices in response to 

disease, this may have affected the study’s ability to 

detect an association between the practice and being a 

case farm. Therefore, the study findings did not refute 

the importance of these practices for the control or 

prevention of clostridial dermatitis. A prospective study 

or a clinical trial could be used to further analyze these 

practices. However, clinical trials are costly and time 

consuming. 

 To further investigate risk factors for clostridial 

dermatitis, another analysis was performed using the 

last completed flock on each of the 36 case farms. This 

analysis compared flocks that had mild or minimal 

clostridial dermatitis with flocks with moderate or severe 

clostridial dermatitis, to evaluate interventions used on 

case farms. The following definitions for the severity of 

clostridial dermatitis were used: 

0

20

40

60

80

Control

Case

Litter

composted 

within 200 ft

of poultry barn

Employees

required to

scrub 

footwear

Soil pH 

≥6.0

Characteristic

Percent

Figure 1. Percentage of case farms and control farms

with the following characteristics 

Farm

33

6

23

0.9

55

14

Humidity

≥60 percent

72 70

24
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

 Mild = not treated 

 Minimal = treated once and responded 

 Moderate = multiple or continuous treatment, 

responded 

 Severe = no or poor response to treatment 

 Due to the small sample size, and because threefourths of case farms had a moderate to severe 

clostridial dermatitis problem, establishing reliable 

statistical associations was not possible. However, a few 

variables were interesting numerically: water 

acidification, use of direct-fed microbials, and use of 

ionophores. 

 A lower percentage of moderately to severely 

affected flocks had received acidified water or direct-fed 

microbials compared with mildly or minimally affected 

flocks (figure 2). This finding is in agreement with the 

belief that acidification may help control or prevent this 

disease by creating conditions that are less favorable for 

clostridial growth. Similarly, direct-fed microbials alter gut 

flora and may cause a competitive inhibition of clostridial 

growth in the gut. 

 In addition, an apparently lower percentage of 

moderately to severely affected flocks than mildly or 

minimally affected flocks had received ionophores. This 

result was unexpected. The questionnaire did not collect 

information on timing or duration of administration of 

ionophores. These intervention strategies deserve 

further investigation in future studies. 

Summary 

 The NAHMS study verified that high environmental 

humidity and high soil PH contribute to clostridial 

dermatitis and identified two measures that might aid in 

the prevention or control of clostridial dermatitis: 

footwear scrubbing by employees and keeping litter 

composting sheds more than 200 feet from poultry 

barns. 

 Water acidification and administering direct-fed 

microbials or ionophores may be effective in reducing 

the severity of clostridial dermatitis on affected farms, 

but further research is needed in this area. 

References

Best EL, Fawley WN, Parnell P, Wilcox MH. 2010. The potential for 

airborne dispersal of Clostridium difficile from symptomatic patients. 

Clin Infect Dis 50(11):1450–1457. 

Chai T, Müller W, Zucker BA. 1997. Airborne microorganisms in animal 

stables. 1. Anaerobic airborne bacteria in a calf stable with special 

regard to Clostridium perfringens. Berl Munch Tierarztl Wochenschr 

110(1):1–4.

Clark S, Porter R, McComb B, Lippert R, Olson S, Nohner S, 

Shivaprasad HL. 2010. Clostridial dermatitis and cellulitis: an emerging 

disease of turkeys. Avian Dis 54(2):788–794. 

Keessen EC, Donswijk CJ, Hol SP, Hermanus C, Kuijper EJ, Lipman 

LJ. 2011. Aerial dissemination of Clostridium difficile on a pig farm and 

its environment. Environ Res 111(8):1027–1032.

Pillai SD, Widmer KW, Dowd SE, Ricke SC. 1996. Occurrence of 

airborne bacteria and pathogen indicators during land application of 

sewage sludge. Appl Environ Microbiol 62(1):296–299. 

Tellez G, Pumford NR, Morgan MJ, Wolfenden AD, Hargis BM. 2009. 

Evidence for Clostridium septicum as a primary cause of cellulitis in 

commercial turkeys. J Vet Diagn Invest 21:374–377. 

USAHA. 2010. Transmissible diseases of poultry report. 

WATT Poultry USA Turkey Profiles, Feb. 2010. 

_____________________________ 

For more information, contact: 

USDA:APHIS:VS:CEAH 

NRRC Building B, M.S. 2E7 

2150 Centre Avenue 

Fort Collins, CO 80526-8117 

970.494.7000 

http://nahms.aphis.usda.gov

#655.0812 

____________________________________ 

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0

20

40

60

80

100 Mild or 

minimal

Moderate 

or severe

Acidified the

birds’ drinking

water

Flock fed

ionophores*

Characteristic

Percent

Figure 2. Percentage of case farms with the following

characteristics, by severity of clostridial dermatitis in

the last completed flock

44

75

67

Flock fed

direct-fed

microbials/

probiotics

54

100

50

*Includes Coban and Avitec coccidiostats.

Severity