Chronic Progressive Lymphedema in Belgian Draft Horses: Understanding and Managing a Challenging Disease

Abstract

Chronic progressive lymphedema (CPL) in draft horses is characterized by increased dermal thickness and fibrosis, with the development of skinfolds and nodules, hyperkeratosis, and ulcerations on the distal limbs of affected horses. Secondary bacterial, fungal, or parasitic infections frequently complicate and aggravate the lesions, as well as the progression of this disease. CPL has a particularly high prevalence of up to 85.86% in the Belgian draft horse breed. Due to the disease’s progressive and incurable nature, affected horses are often euthanized prematurely. The treatment options are solely symptomatic, aimed at improving the horse’s quality of life. Despite the severity of this condition, many uncertainties about its etiology and pathogenesis still remain to date. The established scientific research on CPL is rather limited, although there is an urgent need for strategies to tackle this disease. This review summarizes the available knowledge, serving as a guideline for practitioners, and provides perspectives for future research programs.

The Estimation of Genetic Parameters for Chronic Progressive Lymphedema and Body Traits in the Rhenish German Draught Horse

“…Chronic progressive lymphedema (CPL) is an incurable disease, progressing throughout the life of horses with swelling, skin thickening and crusting, hyperkeratosis, fibrosis, skin folds, and nodules, often complicated with exudative wounds and ulcerations or even with verrucous lesions, of the distal limbs . Secondary bacterial, fungal, and recurrent parasitic infections worsen and complicate lesions [8][9][10]13,14,19,21]. Finally, CPL leads to disability of limbs, loss of appetite, and condition deterioration [4,9,10,19,21].…”

“…Secondary bacterial, fungal, and recurrent parasitic infections worsen and complicate lesions [8][9][10]13,14,19,21]. Finally, CPL leads to disability of limbs, loss of appetite, and condition deterioration [4,9,10,19,21]. Draught horse breeds, particularly in breeds with genealogical relationships with Belgian draught horses [2][3][4]10,19], are the only breeds that have been reported as susceptible to this disease.…”

“…Draught horse breeds, particularly in breeds with genealogical relationships with Belgian draught horses [2][3][4]10,19], are the only breeds that have been reported as susceptible to this disease. Reports on CPL include Ardennes [6]; Belgian [1,4,8,15,16,19,21,22]; Breton [6]; Boulonnais [6]; Cheval de Trait Auxois [21]; Clydesdale [1,4,7]; Comtois [19]; Danish draught [1]; Friesian [23]; German draught such as Black Forest, Mecklenburg, Rhenish German, Schleswig, Saxon-Thuringian, South German [1][2][3][4][5][10][11][12][13]20,24], and Gypsy Cobs; Gypsy Vanners [14]; Shire [1,4,7]; Trait du Nord; and Trait Mulassier Poitevin [18]. Anecdotal studies presumed large genetic effects on CPL based on progeny records of stallions [1][2][3]5].…”

“…For three loci (ECA 1, 10, and 17), immune-response-associated genes were located within these loci. A vicious cycle of interconnected and reinforcing-each-other factors were claimed to be the key players in CLP pathogenesis [21]. The main components may be the lymphatic elastic system with a failing elastic network and chronic inflammation leading to an overregulated inflammatory immune response [26][27][28][29] as well as autoimmune responses [13,21,24].…”

“…A vicious cycle of interconnected and reinforcing-each-other factors were claimed to be the key players in CLP pathogenesis [21]. The main components may be the lymphatic elastic system with a failing elastic network and chronic inflammation leading to an overregulated inflammatory immune response [26][27][28][29] as well as autoimmune responses [13,21,24]. The genetic disposition may be present in any of the components initiating and driving CPL [10][11][12]19,21,22].…”