Cutaneous Leishmaniosis caused by Leishmania martiniquensis in a Horse in Florida.

The study presents a new case of a skin disease called cutaneous leishmaniosis caused by a protozoan parasite, Leishmania martiniquensis, found in a horse in Florida. This indicates that this specific parasite might have established a persistent presence in the state.

Research Background

• The study presents a single case of cutaneous leishmaniosis in a 10-year-old neutered male Quarter horse in Florida.
• Leishmaniosis is a parasitic disease caused by Leishmania.
• In this particular case, the pathogenic species was identified as Leishmania martiniquensis.
• This specific species is associated with pyogranulomatous dermatitis, a skin condition characterized by inflammation, which results in ulceration (open sores) and oozing.
• The primary evidence came from the non-healing wounds observed on the horse’s ears, which had persisted for several weeks and regressed spontaneously after a few months.

Investigative Method

• Microscopical examination was conducted on biopsies taken from the lesions on the horse’s ears, revealing epidermal hyperplasia (abnormal increase in the number of skin cells), ulceration and pyogranulomatous inflammation (clustered immune cells fighting infection).
• The researchers also observed numerous intact and degenerate neutrophils (type of white blood cells) surrounded by different types of immune cells.
• They also discovered small round protozoa within the macrophages (cells that consume harmful particles) and inflammatory infiltrate.
• To identify the parasite, immunohistochemistry and colourimetric in-situ hybridization were performed, providing positive results for amastigote forms of Leishmania spp. (one of the life stages of this parasite).
• The researchers confirmed the presence of L. martiniquensis using polymerase chain reaction (PCR), a technique used for making multiple copies of a specific DNA segment, on extracts of tissue samples from skin lesions.

Significance

• This study is significant because it’s the second confirmed case of leishmaniosis caused by L. martiniquensis in Florida in the past five years.
• This prompts a suggestion that the parasite may have become endemic in Florida, meaning that it may be regularly found among particular people or in a certain area.
• More research will need to be done to confirm this, as the disease can have serious health impacts and could potentially spread to other states or regions.