Lumpy Skin disease lesions
Recently, for the first time in Catalonia and the Iberian Peninsula, several outbreaks of lumpy skin disease (LSD), a viral disease of cattle, have been confirmed. This disease is on the list of Category A diseases, which means that, by regulation, measures must be taken to eradicate it from the country and prevent the outbreak from spreading.
The measures contemplated are the stamping out of confirmed farms, the restriction of animal movements and the reinforcement of biosecurity measures to prevent transmission between farms. This is complemented by the emergency vaccination of all cattle herds around the outbreak. For eradication to be possible, it is key that all outbreaks that may exist in the territory are detected early. Farmers and veterinarians who see compatible clinical signs (passive surveillance) must notify the competent authorities so that they can take samples and rule out or confirm the suspicion. And it is necessary to carry out active surveillance on farms around outbreaks to detect new cases that may have been overlooked.
Surveillance at the slaughterhouse also plays a key role in detecting outbreaks that may have escaped the active and passive surveillance mechanisms on the farm.
In this post we show you images of lesions compatible with dermatosis to familiarize yourself with them, in case of suspicion you must follow the protocols for reporting notifiable diseases.
There are several etiologies that can cause the appearance of skin nodules, some of which we will also show in this post, such as arthropod bites, demodicosis or the presence of cutaneous lymph nodes. In the current epidemiological situation, we recommend sending any skin nodular lesion that you observe in cattle or buffalo carcasses to the laboratory urgently. The laboratory will rule out the suspicion using PCR and histopathology.
The sample of choice for laboratory diagnosis is the skin nodule, as this is where the highest viral load is found. Viremia (blood+EDTA) and virus excretion through secretions (oral/nasal/ocular swabs) are intermittent and may be negative in infected animals. (EV and AC)
A) Antemortem. Skin. Cattle, farm with confirmed LSD. Generalized multifocal nodular dermatitis. B) Ulcer on the nasal mucosa. C) Ulcers on the tracheal mucosa.
Antemortem. Cattle, farm with confirmed LSD. Nasal and ocular discharge.
Skin. Cattle, farm with confirmed LSD. A) Generalized multifocal nodular dermatitis. Acute nodules (~1-2 weeks). B) Histological image at low magnification. The arrow indicates the nodular lesion, with a predominantly necrotic component. C) Detail of the lesion at higher magnification showing necrosis of the dermis and mononuclear inflammatory infiltrate.
A) Lung. Cattle, farm with confirmed LSD (field necropsy). Interstitial emphysema. Histologically the lung showed severe acute interstitial pneumonia. B) Proliferative pleuritis in the costal serous pleura.
Skin. Cattle, farm with confirmed LSD. A) Generalized multifocal nodular dermatitis. Sub-acute nodules (~3 weeks). B) Histological image at low magnification. In this case, an area of coagulative (ischemic) necrosis surrounded by a mononuclear inflammatory infiltrate is observed. C) Detail of the lesion at higher magnification, necrosis of the dermis (*), vasculitis (arrow) and mononuclear inflammatory infiltrate can be observed.
Skin. Cattle, farm with confirmed LSD. Appearance of the nodules in section. Chronic nodules with crust formation at the level of the superficial dermis (~ 4 weeks). On the right the histological image where an area of coagulative (ischemic) necrosis can be seen surrounded by a ring of mononuclear inflammation and the formation of incipient granulation tissue.
Skin. Cattle, farm with confirmed LSD. More chronic nodules (~3-4 weeks). A) Deep dermis and subcutaneous tissue involvement. Histologically, an area of coagulative (ischemic) necrosis with a mononuclear inflammatory infiltrate underneath can be observed. B) Lesion of similar chronicity but with less involvement of the subcutaneous tissue.
Skin. Cattle, farm with confirmed LSD. A) Nodule before hair clipping. B) Nodule after hair clipping. Long hair can hide nodules and make it difficult to detect nodules if the animal's skin is not palpated. C) Section of the nodule. The area of coagulative (ischemic) necrosis can be seen as a red well demarcated area. D) Histological image of the nodule, a mononuclear inflammatory infiltrate can be seen around and below the ischemic area. This is a chronic lesion 3-4 weeks of age.
Skin. Cattle, farm with confirmed LSD. A) Example of a chronic nodule with the crust already detached and leaving an ulcerated lesion (~4 weeks). B) Section of the nodule and the crust. C) Histological image where it can be observed that the granulation tissue has replaced the space occupied by the nodule, pushing the crust outwards, and the epidermis remains in the process of re-epithelialization and the dermis without hair follicles or appendages.
Cattle. Skin, farm with confirmed LSD. A) Antemortem. Presence of multiple nodules on the flank (arrow). B) When removing the nodule it is observed that it does not affect the dermis or epidermis, it is a subcutaneous nodule. C) Histological study of the same sample showing it consists of a hyperplastic subcutaneous lymph node.
Cattle. Skin. A) Case submitted to SESC of a carcass with multiple skin nodules. B) Section of one of the nodules showing a well-circumscribed dermal lesion, which does not affect the epidermis. C) Histological section showing dermatitis with abundant eosinophils and the presence of Demodex spp mites (insert), therefore these are demodicosis lesions. The PCR for capripoxvirus was negative.
Skin. Cattle. Cases submitted to SESC of carcasses with a few skin nodules. A) Alopecic nodular lesion with thickening of the dermis. Histologically it corresponds to an eosinophilic dermatitis compatible with hypersensitivity to arthropod bites. B) Dermal nodular lesion, well delimited, histologically also corresponds to an eosinophilic dermatitis, compatible with arthropod bites. In this case, despite not observing lesions histologically compatible with LSD in the samples studied, the PCR for the genus capripoxvirus was positive in both animals, at postmortem examination interstitial pulmonary emphysema and lymphadenopathy of the prescapular lymph nodes were also observed in the slaughterhouse.
