Pythiosis in the Nasal Cavity of Horses.

This study explores two documented instances of nasal pythiosis, a fungal infection, in horses from a semi-arid region in northeastern Brazil. Over a twenty-nine year period, of 156 horses diagnosed with pythiosis, only two presented with lesions in the nasal cavity, a condition found to occur sporadically in this area where cutaneous pythiosis is more common.

Research Context

• The study was conducted in the Laboratory of Animal Pathology at the Federal University of Campina Grande in Brazil over 29 years, from January 1986 to December 2015.
• Over the period of research, the laboratory received 830 samples from horses, out of which, around 18.79% or 156 horses were diagnosed with a fungal infection known as pythiosis.
• This disease is caused by the Pythium insidiosum, a pathogen that commonly affects horses.

Findings

• Of the horses diagnosed with pythiosis, only two instances were noted where the lesions were found in the nasal cavity, making up only 1.28% of the total diagnoses. This indicates that nasal pythiosis in horses in the studied region is not very common.
• The two cases involved an adult male and female cross-breed horse, both of which had access to water reservoirs.
• The symptoms included swelling in the rhinofacial region (nose and face) and a discharge from the nose that contained both serum (a component of blood) and blood.
• The study revealed that the lesions were characterized by a yellow-grey granular surface with cavities of varying sizes. Within these cavities were coral-like masses of necrotic (dead) tissue, known as kunkers.
• Upon microscopic examination, the samples showed hyphae, filamentous structures associated with fungal growth, resembling the structure of Pythium insidiosum.
• In the more severe of the two cases, the lesions spread from the nasal cavity to surrounding tissues, including muscle, cartilage, bone and lungs.

Conclusions

• The study confirmed the suspicion of nasal pythiosis through a diagnostic procedure called immunohistochemistry, which involves the use of antibodies to detect the presence of certain cells or tissues.
• The research concludes that the occurrence of nasal pythiosis happens sporadically in horses in northeastern Brazil, a semi-arid region where the skin manifestation of pythiosis (cutaneous pythiosis) is more prevalent.