University:
Texas A&M University
Course:
BIOL 318 | Chordate Anatomy
Academic year:

2020
Views:

134

Pages:

66
Author:

Lamghari6kx

Malignant Catarrhal Fever Symptoms Host Range The disease can occur in cattle, domesticated buffaloes, a wide range of captive antelopes and deer, and free-living deer. Host Range Under natural conditions only domestic cattle and deer develop clinical signs MCF has never been reported in freeliving wild animals in Africa Host Range In zoological collections a wide variety of ruminant species have been reported to develop clinical signs Rabbits can be infected experimentally Host Range It was recently confirmed in pigs in Scandinavia Reservoir ruminant species Blue wildebeest Black wildebeest Domestic sheep Goats Blue Wildebeest Black Wildebeest Transmission Neonatal and adolescent wildebeest shed virus Transmission from reservoir animals to domestic cattle, deer contact with calving wildebeest contact with lambing sheep Cattle are more susceptible to Wildebeest derived MCF than to the sheep or goat MCF Congenital Transmission Cow will die then later calf will die Malignant Catarrhal Fever: Clinical Signs In some cases MCF presents as chronic alopecia and weight loss as with deer infected with the Caprine herpesvirus. However, MCF is typically fatal. Clinical Signs There are many factors that affect the duration of the disease in different species The severity of the clinical symptoms will depend on those factors. Mortality is usually 100% but some animals face weeks of progressive disease For this reasons, once the disease is identified, most elect to euthanized the affected animal. Clinical Signs High fever 106-107°F (41-41.5°C) Depression In deer - sudden death Deer and bison that survive 2-3 days: – Hemorrhagic diarrhea – Bloody urine – Corneal opacity – Then death Clinical Signs The longer the animal survives the course of the disease the more severe the signs become. For example, animals that die acutely may not develop lymphadenopathy or corneal opacity As the disease progresses: Catarrhal inflammation Erosions and exudates in upper respiratory tract, ocular and oral mucosa Swollen lymph nodes Lameness CNS signs (depression, tremors, stupor, hypo-responsive, aggression, convulsions Clinical Signs On average the time to death for European cattle is longer than for deer, bison and water buffalo; usually 7-17 days after the appearance of clinical signs In cattle the swollen lymph nodes and severe eye lesions are more frequent Clinical Signs Hemorrhagic enteritis and cystitis are more frequently seen in bison and deer than in cattle Skin lesions are common in animals that do not succumb quickly Most eventually die, about 5% recover clinically Clinical signs Depressed and VERY SICK Stertorous respiration Enlarged lymph nodes Clinical Signs Animals suffer, are painful and cannot breathe well Clinical Signs Secondary bacterial bronchopneumonia may be eventual cause of death if not euthanized first Clinical Signs Painful swollen eyes Clinical Signs Ocular and nasal discharge Clinical Signs “snotsiekte” Mucopurulent discharge, crusting occludes the nostril; animal begins open mouth breathing. Characteristic of MCF Early corneal opacity begins at the limbus Progresses to total opacity Clinical Signs Severe panophthalmitis, hypopion, corneal erosions are more frequent in cattle Severe Ocular lesions Painful Conjunctivitis Severe Ocular lesions Progresses to corneal opacity beginning at Limbus Severe Ocular lesions Characteristic eye lesions Severe Ocular lesions Characteristic eye lesions Severe Ocular lesions Oral Lesions Erosions on gums, dental pad and near teeth Oral Lesions Erosions near the teeth Oral Lesions Necrosis of papillae similar to rinderpest Oral Lesions Erosions here are similar to bluetongue in Africa Oral Lesions Erosions of papillae Oral Lesions Erosions in squamous (anterior) portion of nasal cavity Enlarged and edematous lymph nodes Moist necrotic dermatitis with exudation and encrustations Skin lesions associated with both sheep form and wildebeest derived. Resembles foot-and-mouth disease Mild diarrhea sometimes seen which is black and tarry, but not effusive In terminal stages CNS symptoms: falling, circling, head pressing, high stepping convulsions, then death Clinical Signs in Swine From a case in Norway: Symptoms reported as: hyperemic conjunctiva, vomiting, restlessness and anorexia. The rectal temperature was 41° C, the respiratory rate was 33 per minute, and the heart rate was 110 per minute. Despite parenteral antibiotic treatment, the symptoms worsened and the pig died 5 days after onset of disease. Over a short period, three other adult swine in the same herd died after showing similar clinical signs. Clinical Features Summary Incubation period is LONG – weeks to months Morbidity LOW Clinical illness – weight loss, enlarged lymph nodes, corneal opacity, rhinitis Mortality – 100% Diagnosis at Necropsy The disease is systemic and lesions can be found in any organ Inflammation and necrosis of the respiratory, alimentary and urinary mucosa Generalized lymphoid proliferation and necrosis Widespread vasculitis Focally disseminated erosions and ulcerations in the GIT Focally disseminated erosions and ulcerations in the GIT “button ulcers” 5-10 cm erosions Frequently see erosions in the bladder mucosa Lymphoid infiltration Multifocal lymphoid infiltration Multifocal lymphoid infiltration Enlarged lymphoid tissue – everywhere – looks like lymphoma Lymph nodes – TOO BIG Tonsils bulge Hemal nodes are prominent Spleen infiltrated Peyer’s patches stand out Diagnosis Diagnosis Histopathology T lymphocyte hyperplasia, cell necrosis Histopathology Severe necrotizing vasculitis Perivascular lymphoid infiltration Histopathology Perivascular lymphoid infiltration of arterioles Summary Think Malignant Catarrhal fever when: Only a few cattle are affected and they die Cattle have been exposed to sheep during lambing season Cattle have severe respiratory symptoms and conjunctivitis with cornel opacity Lesions are on the ventral side of the tongue

Malignant Catarrhal Fever Symptoms

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