Fusobacterium necrophorum, and not Dichelobacter nodosus, is associated with equine hoof thrush

Treponema spp. spirochetes and keratinopathogenic fungi isolated from keratomas in donkeys

Keratoma is an aberrant keratin mass thought to originate from epidermal horn-producing cells interposed between the stratum medium of the hoof wall and the underlying third phalanx. The cause is unknown, although the presence of keratomas is frequently associated with chronic irritation, focal infection, or trauma. A total of 167 donkeys with keratomas were presented in this study. The diagnosis of a keratoma was based on clinical signs, radiography, and histopathologic examination. Surgical excision was attempted on all donkeys with lameness unless euthanasia was advised. Histopathologic examination, including Giemsa, periodic acid Schiff, and Young's silver special histochemical stains, was performed and showed the presence of fungal hyphae and spirochete bacteria within the degenerate keratin. Polymerase chain reaction (PCR) for treponeme bacteria was performed on 10 keratoma lesions and 9 healthy pieces of hoof (controls). All healthy donkey tissues were negative for the 3 recognized digital dermatitis (DD) treponeme phylogroups, whereas 3 of 10 (30%) donkey keratoma samples were positive for one of the DD treponeme phylogroups. Routine fungal culture and PCR for fungi were performed on 8 keratoma lesions and 8 healthy pieces of hoof (controls). Keratinopathogenic fungi were detected in 1 of 8 (12.5%) keratomas, while only non-keratinopathogenic, environmental fungi were detected in 8 control healthy hoof samples. This is the first time the DD treponemes phylogroup and keratinopathogenic fungi have been detected in keratomas. Further studies are required to assess the significance of this finding.

Effect of Cooling Blanket on the Heat Stress of Horses in Hot and Humid Environments

Simple Summary

Heat stress is serious problem for livestock. While riding horses and racehorses spend the majority of their days in stalls, there are few reports on effective methods for reducing stall heat stress. The aim of the present study was to evaluate the effectiveness of an ice horse blanket in hot and humid environments. Twenty healthy horses were measured first without the blanket (C) and then measured with the blanket (IB), or vice versa, in a cross-over trial. The blanket was designed to keep cooling the front back, the rear back, and the loin. The skin surface temperature of the front back was decreased with cooling time in IB, whereas it was not changed in C. Similarly, respiratory rate and plasma cortisol level also decreased only in IB. The blanket used in the present study had the advantage of allowing for gentle cooling of the horse’s body without the use of water or fans. Applying this methodology should enable effective reduction of heat stress not only in horses but also in other mammals kept in barns.

Abstract

Heat stress is serious problem for livestock. While riding horses and racehorses spend the majority of their days in stalls, there are few reports on effective methods for reducing stall heat stress. The aim of the present study was to evaluate the effectiveness of an ice horse blanket in hot and humid environments. Twenty healthy horses were measured first without the blanket (C) and then measured with the blanket (IB), or vice versa, in a cross-over trial. The blanket was designed to keep cooling the front back, the rear back, and the loin. Skin surface temperature, respiratory rate, rectal temperature, and plasma cortisol level in both C and IB were measured at 10:00, 12:30, and 15:00. The skin surface temperature of the front back was decreased with cooling time in IB, whereas it was not changed in C. Similarly, heart rate, respiratory rate, and plasma cortisol level also decreased only in IB. The blanket used in the present study had the advantage of allowing for gentle cooling of the horse’s body without the use of water or fans. Applying this methodology should enable effective reduction of heat stress not only in horses but also in other mammals kept in barns.

Reducing exposure to pathogens in the horse: a preliminary study into the survival of bacteria on a range of equine bedding types

AIMS

To compare the rate of growth of four microbial strains that cause disease in the horse, on four commonly used types of bedding. The moisture-holding capacity of each bedding type was also tested.

METHODS AND RESULTS

Microbial strains included Streptococcus equi, Streptococcus zooepidemicus, Fusobacterium necrophorum, Dichelobacter nodosus and Dermatophilus congolensis. The bedding types tested were Pinus sylvestris (Scots pine shavings), Pinus nigra (Corsican pine shavings), Picea sitchensis (Sitka spruce shavings), Cannabis sativa (hemp) and chopped wheat straw. A suspension of each microbial strain was spread in triplicate on agar media and incubated in its optimal growth conditions. The viable count (colony-forming unit per ml) was determined for each bacterial strain for the five different bedding types. Pinus sylvestris bedding resulted in significantly less (P = 0·001) bacterial growth of all strains tested.

CONCLUSIONS

Factors resulting in the inhibition of bacterial growth include the antibacterial effects reported in the Pinacea family and the physical properties of the bedding substrate. Research is currently focussed on the diagnosis and management of disease. Prevention of disease is also important for matters of biosecurity. Strategies should include the provision of a hygienic environment and the use of specific types of bedding.

SIGNIFICANCE AND IMPACT OF THE STUDY

Bedding choice has implications for global equine health and disease prevention as well as potential benefits in other animal species.

Isolation and identification of Dichelobacter nodosus and Fusobacterium necrophorum using the polymerase chain reaction method in sheep with footrot

Footrot is an important infectious disease of small ruminants leading to severe economical losses. The aim of the present study was to determine isolation and identification rates ofDichelobacter nodosusandFusobacterium necrophorumin the culture techniques and reveal the specificity and sensitivity of the culture technique based on the polymerase chain reaction (PCR) method in sheep with footrot. Dry swabs and swabs with Amies medium from 83 sheep were subjected to PCR and culture analyses. In dry swabs, 4 samples were positive forF. necrophorumand all were negative forD. nodosus. Colonies in Eugon and Fusobacterium selective agars from swabs with Amies medium were evaluated. Polymerase chain reaction analysis was conducted on macroscopically and microscopically unidentified samples. The positivity rate was 55.4% forD. nodosusand 69.8% forF. necrophorumin cultures from Fusobacterium selective agars. The positivity rate forD. nodosusin Fusobacterium selective agars was higher than that in Eugon agar. Performing PCR and culture methods increased positivity as compared to performing them alone. In comparison with the PCR method, culturing in Fusobacterium selective agars had moderate sensitivity and low specificity forD. nodosus(71.7 and 28.7%) andF. necrophorum(61.3 and 80.0%), respectively. In conclusion, Fusobacterium selective agar (without antibiotics) for isolation and identification ofD. nodosusis superior to Eugon agar.Fusobacterium necrophorumshould also be considered as a provoking agent for footrot in small ruminants. The PCR method on culture increases elucidation of definitive aetiology.