Epidemiology of epizootic lymphangitis of carthorses in northern Ethiopia using conventional diagnostic methods and nested polymerase chain reaction

Abstract

Background Epizootic lymphangitis (EL), caused by Histoplasma capsulatum variety farciminosum (HCF) is a contagious, chronic disease of equines, characterized by development of nodular lesions in the lymph nodes, lymphatic vessels and skin. It is one of the most important diseases of equines in Ethiopia, causing significant economic loss, particularly in the livelihood of carthorse owners. To date there is neither effective diagnostic nor control measure implemented in the country. Furthermore, there is a shortage of data on the epidemiology of the disease in different regions of this country. The aim of this study was to investigate epidemiology of EL in northern Ethiopia, using the conventional methods as well as nested polymerase chain reaction (PCR). Results The presence of HCF genetic material was confirmed in 44% (84/191) of the carthorses. Subclinical infection was observed in 18.2% (22/121) of the apparently healthy carthorses. Considering the nested PCR as a gold standard, sensitivity and specificity of clinical examination were 74% and 92.5%, respectively, while the area under the ROC curve (AUR) was 0.83 (95% confidence interval, 0.77, 0.896). Moreover, a moderate (k = 0.675) agreement observed between the nested PCR and clinical examination. Conclusions This study demonstrated widespread occurrence of EL in northern Ethiopia, and the advantage of the nested PCR in detecting infection of HCF, even before the clinical symptoms became apparent.

Epidemiology of Epizootic Lymphangitis Among Carthorses in Ethiopia

“…Although the sample size and area coverage are limited in our study the results confirm to the previous study ( 7 ) suggesting the widespread occurrence of epizootic lymphangitis in carthorses throughout Ethiopia. On the other hand the prevalence observed in this study is lower than the reports of Hadush et al ( 14 ) from northern Ethiopia (44%). Our observation is higher than the reports of Wilson ( 15 ) from Sudan (17–58 cases per year) and that of Abdullahi et al ( 16 ) from Nigeria (5.6%).…”

Control and Prevention of Epizootic Lymphangitis in Mules: An Integrated Community-Based Intervention, Bahir Dar, Ethiopia

“…EZL prevalence in 2010 was within the range reported across Ethiopia in cart horses (16,55), which varied from 39.1% in Mojo to 21.1% in Nazret, and was comparable to reports from Ejaji and Bako where prevalence was 21% in cart mules (17). Prevalence of wounds in 2010 was also comparable to previous reports in Bahir Dar and the adjacent town of Adet (8,56), where most wounds were also associated with poor harnessing practice (10).…”

Prevalence and risk factors of epizootic lymphangitis in cart pulling horses and mules in Central and South Gondar zones, Amhara region, Ethiopia

“…The prevalence was determined on based samples from clinically affected animals and as such the prevalence refers to only the clinical prevalence of the disease. But use of advanced laboratory diagnostic tests such as polymerase chain reaction indicated the existence of the subclinical form of the disease [ 40 ].…”