Fungal Diseases in Chickens

Dermatomycosis of the cockscomb

Ringworm of the crest. Dermatomycosis:

Dermatomycosis is a contagious infectious disease, a fungal infection that typically causes lesions on the scalp, Microsporum gallinae, Trichophyton gallinae.

It is also known by:

  • Ringworm of the crest.
  • Spots of the crest.
  • Crest white.
  • Tinea favosa.

This condition is characterized by the formation of dandruff-like scabs on the bird’s skin, which are particularly noticeable on areas where feathers are sparse, especially on the crest, face, and wattles. It is transmitted directly through contact with an infected bird and indirectly through the air when birds are in close proximity to one another.

Over time, these scabs grow in size and number, forming round, ash-white scabs. To evolve, the fungus can get to expand in the neck and the body, attacking the base of the feathers and causing them to break and fall.

Ringworm is contagious; therefore, it is advisable to isolate the infected animal and disinfect the premises. It should be noted that the ringworm fungus thrives in dark, overcrowded, and damp chicken coops.

Etiology:

This disease is caused by a pathogenic fungus of the genus Trichophyton, specifically Trichophyton gallinae. This zoophilic dermatophyte infects chickens and rarely infects humans.

The Trichophyton gallinae It grows quite well on standard fungal media (Sabouraud, Czapek) enriched with thiamine, producing abundant macroconidia. The colony is glossy and white, with a striking red pigment.

 

Susceptible species:

They are considered susceptible to ringworm all species of mammals, birds, and even reptiles.

This disease primarily affects domestic chickens (Gallus domesticus), particularly those breeds with large combs.

Turkeys (Meleagris gallopavo) can become also and developing the disease in the areas implumes of the head.

Ringworm is more common during the colder months, when humidity is low and rainfall is scarce. Keeping animals in warm, damp, dirty stalls with thick layers of manure promotes infection.

Similarly, the overcrowding in intensive production makes the animals more receptive.

Routes of transmission:

The disease spreads slowly through direct contact from one bird to another; it is also commonly transmitted when sick and healthy birds come into contact with feeders and waterers.

The scales shed by sick animals are a source of infection that can contaminate healthy birds.

Not considered to be unlikely, the possibility that these scales are ingested or inhaled the powder in the chicken coop and accentuate the lesions in internal organs.

The disease progresses more rapidly when the skin abraded or lacerated.

This disease has a presentation enzootic and markedly seasonal, disappearing with the onset of the summer rains.

Cultivation of Microsporum gallinae

Clinical manifestations:

As the fungus spreads throughout the chicken coop, white patches resembling scales begin to appear on the birds' combs.

The crest and wattles appear as if they had been dusted with flour. As the disease progresses, the fungus can also take hold in the feathered areas, causing the feathers to begin falling out; around the base of the feathers, we observe scaly crusts and thickening of the skin.

The disease may be accompanied by general symptoms such as depression, weakness, weight loss, anemia, etc.

The evolution goes on sometimes way to chronicity, although there are animals where it has been observed the spontaneous cure.

The lethality is low when you maintain the hygiene measures.

The area of skin affected by the fungal infection is thickened and covered with scabs; in addition to external lesions, some birds exhibit necrotic foci, nodules, and yellowish caseous deposits on the mucous membranes of the upper respiratory tract or the digestive tract.

Histopathological examination reveals caseous necrosis in the crop or small intestine; these lesions also show signs of favus.

Microsporum gallinae, on a rooster's wattle

Microsporum gallinae, on a rooster's wattle

Diagnosis:

Clinical diagnosis is fairly straightforward and often accurate, as abnormalities in the crest, chin, and featherless areas of the skin strongly support our diagnosis.

In case of doubts or broader research, we resort to the diagnostic laboratory, where in culture or microscopic examination direct, it highlights the causal agent.

In addition, the biological diagnosis and the epizootiological data obtained complement the investigation.

As a therapeutic can use solutions of iodine, green soap and others, although this treatment is individual and not advised in the offspring modern intensive.

Follow-up treatment:

First, apply a disinfectant—use iodine, especially for conditions affecting the crest area, since it is non-irritating and because we are treating a fungal infection.

The iodine we can apply it while you brush the area with a toothbrush (soft), to try to exfoliate the affected area. We use disposable gloves, and make sure that the brush is always moist to prevent flakes that could be sources of infection in the future.

Once cleaned and disinfected the area, we proceed to dry it and clean it with a sterile gauze pad, and in this step we could apply some antifungal cream, such as those that contain miconazole, clotrimazole, or similar ingredients.

This treatment repeat for several days, including brushing. If, unfortunately, the infection has spread to deep area of the skin to the hair follicle, it is possible that you need topical antifungal medication stronger, such as ketoconazole or similar. We may also require antibiotics to treat secondary bacterial infections.

Infections are very steep, you can also manage the bird some antifungal oral as an adjuvant.

Microsporum gallinae, rooster comb

Microsporum gallinae, in chicken face

Microsporum gallinae, chicken comb and face

Literature review:

MERCK & CO. (1995). Manual Merck de Veterinaria. Rahway, N. J., EE. UU.

BUXADÉ, P. (1987). The laying hen. Ed. Mundiprensa. Madrid.

DORN, P. (1987). Manual of avian pathology. Ed. Acribia. Zaragoza.

HOFSTAD, M. S. (1984). Diseases of Poultry. Iowa State University Press, Ames, Iowa.

ZARZUELO, E. (1982). Vade mecum of the pathology, infectious poultry. Ed. Aedos, Barcelona.

CASTELLÓ, F. and CASTELLÓ, J. A. (1960). The New Art of Raising Chickens. Aedos, Barcelona.

OROZCO, F. (1989). Breeds of chickens Spanish. Ed. Mundiprensa. Madrid.

LACADENA, J. R. (1998). Genetics. Ed. AGESA

PUERTAS, M.J. (1992). Genetics: Fundamentals and Perspectives. McGraw-Hill Interamericana.

SANCHEZ-MONGE, E. (1969), Genetics. Espasa-Calpe S.A.

OROZCO, F. and ROBLA, F. (1986). Genetic aspects of the León rooster. 24th Symposium of the WPSA (Spanish Section): 199–212.

HILL, J. L. (1973). Genetics, general and applied. Ed. UTEHA.

CASTELLÓ, J. A., LLEONART, R., FIELD, J. L., OROZCO, F. (1989). Biology of the chicken. Real Escuela de Avicultura.

LLEONART, F., ROCA, E., CALLÍS, M., GURRI, A., PONTES, M. (1991). Poultry Hygiene and Pathology. Royal School of Poultry Science.

STURKIE, P.D. (1968). Fisiología aviar, ed. Acribia. Zaragoza.

LOHMANN ANIMAL HEALTH (2012)

 

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