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Review of Clinical Signs of Foreign Animal Diseases
Extension Veterinarian Veterinary Medicine Extension University of California, Davis Veterinary Medical Teaching and Research Center Tulare, CA
Contents Vesicular Diseases Contagious Bovine Pleuropneumonia Bovine Spongiform Encephalopathy
Vesicular Diseases Foot-and-Mouth Disease FMD Definition: FMD is an acute, highly communicable disease seen almost exclusively in cloven-footed animals (cattle, sheep, pigs, game park hoof stock). It is characterized by the formation of vesicles followed by erosions in the mucosa of the mo uth, external nares and skin between and above the hoof and on the teats. Etiology: Virus with 7 immunologically and serologically distinct types which are Types O, A, and C, Southern African Territories (SAT-1, SAT-2, SAT-3) and Asia-1. Distribution: Most all major cattle producing countries except North America, Central America, Australia, New Zealand, Japan and Ireland. Transmission: The virus is transmitted by contact with infected animals (aerosols primarily), by infected animal products (ingestion) and by contaminated objects. Also by birds and rodents. Carried by wind for long distances. Hosts: All cloven hooved animals, domestic and wild) are naturally susceptible. Clinical signs: Incubation period is 1-5 days or longer. Fever Depression Off feed Excessive salivation Smacking of lips Drooling These signs are caused by formation, rupture and erosion of vesicles in the mouth. Lameness Altered gait This is caused by formation, rupture and erosion of vesicles on the feet. Decreased milk production Less time spent eating due to lesions in mouth. Also lesion possible in GI tract often in the rumen. Mastitis Especially if vesicles form on the teats. Abortions Recovery in 2 weeks with about 5% mortality. Excessive culling due to foot and mastitis problems following the active disease. Differential Diagnosis: All vesicular diseases. Also IBR, BVD, Bluetongue MCF and Contagious Ecthyma.
Vesicular Stomatitis VS Definition: Vesicular stomatitis is a viral disease of horses, cattle and swine. Macules, vesicles and erosions appear successively in the mucous membranes of the mouth, skin of teats and on the feet. Etiology: Virus which has two serotypes - New Jersey and Indiana. Infections are clinical indistinguishable for each other as well as FMD. Distribution: VS occurs mainly in the Western Hemisphere with enzootic areas of the New Jersey and Indiana serotypes. Found often in Mexico, Central America, Panama, Venezuela, Colombia, Ecuador and Peru. In US it has occurred in horses in New Mexico, Colorado, Utah and Arizona over the last few summers. Cattle outbreaks were most recently seen in Idaho and California. Transmission: The ecology of the virus is still uncertain. Often seen during periods of abundant arthropods suggesting that they may be involved in transmission. Hosts: Horse, cattle and hogs. Wild animals also infected (bats, carnivores, rodents). Clinical Signs: Incubation period is from 2-4 days. Same as for FMD Vesicles may tend to locate in one place more than others in most outbreaks. Animal recover in about one week often without serious effects. Secondary infections such as mastitis may occur. While the lesions may heal quickly, economic losses on dairie s may be significant. Differential Diagnosis: All vesicular diseases. Economic losses can be very high due to excessive culling rates in cattle.
Bovine Papular Stomatitis Definition: Widely distributed viral disease with papular and occasionally mild erosive lesions on the muzzle and mouth of young cattle. Etiology: Virus which may be the same virus as Pseudocowpox. Distribution: Reported in US, Africa, Australia, New Zealand, Canada, Great Britain and Europe. Hosts: Primarily calves. Can effect man. Clinical Signs: Transient fever Small papules Small rounded lesions - depressed centers Clinical signs of the disease are very mild and almost always go unnoticed. Lesions heal quickly in 4-7 days. May reoccur in same animal over a period of months. Could be confused with pseudocowpox, FMD, VS, BVD, and Rinderpest.
Rinderpest Definition: RP or cattle plaque is an acute, highly contagious viral disease primarily of cattle but also occurring in sheep, goats and wild ruminants. Just in case you were wondering, the US javelina is very susceptible. Etiology: Virus related to measles and distemper virus. Distribution: Enzootic in Asia and Africa. Not in Europe or the Americas. Transmission: By contact with infected animals or indirectly with secretion or excretion of infected animals, and fomites. Like most viral diseases, the virus is in the blood and secretions before clinical signs appear. Therefore, infected anim als are spreading the virus before anyone knows they are ill. Bad news for stockyards and slaughterhouses. If animals recover, they are solidly immune. Hosts: Chiefly cattle, buffaloes, deer, camels, sheep, goats and once in a while swine. Clinical signs: Three to 10 day incubation period. High fever (104-107 F) Nasal discharge Erosions of mucous membranes - mouth Excessive salivation Constipation, then diarrhea Dehydration Rough appearance Death in 7-12 days with high mortality rate Gross lesions: Punched-out erosions - lips, gums, tongue, soft palate Lymph nodes edematous Inflamed, eroded, hemorrhagic, necrotic Peyer's patches Hemorrhagic mucosa of abomasum Edema, hemorrhage, erosions of cecum, cecocolic junctions, and rectum. Zebra stripped large intestine Differential Diagnosis: Acute mucosal disease (BVD), MCF, acute coccidiosis and perhaps FMD.
Malignant Catarrhal Fever Definition: MCF of Africa (wildebeest associated MCF) is an acute generalized disease of cattle and buffaloes characterized by high fever, profuse nasal discharge, severe hyperemia, diffuse necrosis of oral and nasal mucosa, leukopenia, ophthal mia, corneal opacity and generalized enlargement of lymph nodes. There are four syndromes peracute, intestinal, head and eye (the most common) and mild. Morbidity is usually low, however, mortality is high. Etiology: Herpes virus is the cause of Africa MCF. No proven agent has been found outside of Africa (usually called sheep-associated MCF). Distribution: Africa (wildebeest) MCF is known to occur in South Africa. Sheep associated MCF occurs sporadically on a worldwide basis. Transmission: In Africa, the wildebeest is the reservoir. Elsewhere, sheep are thought to be the reservoir. Close contact is regarded as essential for transmission via nasal discharge. Hosts: Wildebeest and sheep have naturally occurring, inapparent infections. Cattle are secondary hosts. Clinical Signs: Head and eye form: Pyrexia (104-107 F) 7-10 later, nasal and ocular discharges Bilateral serous>>mucoid, mucopurulent, purulent Encrustation of nostril>>dyspnea Mouth breathing and drooling Hyperemia of oral mucosa Diffuse superficial necrosis of all oral mucosa Blunted oral papilla Show severe pain - resist examination of mouth Ocular discharge - lacrimation>>purulent Ophthalmia Corneal opacity - usually bilateral Photophobia - close eyes, look away from light Enlarged lymph nodes - commonly head and neck Increased thirst Anorexia late in course Constipation, perhaps diarrhea at death Death in 7-14 days Gross necropsy lesions: Evidence of purulent discharge, erosions and hyperemia in respiratory tract. Erosions and hyperemia in the GI tract. Perhaps, whitish focal areas in kidneys. Enlarged lymph nodes (2-5x), most commonly of the head and nec k. Differential diagnosis: Bluetongue, BVD, RP, VS-diseases
Contagious Bovine Pleuropneumonia Definition: CBPP is a specific disease of cattle caused by Mycoplasma mycoides, subspecies mycoides. It is highly infectious and occurs in acute, subacute and chronic septicemic forms. Etiology: Mycoplasma specific for cattle. Sheep and goats have their own subspecies. Distribution: Endemic in Africa, also in China and India. Not in western hemisphere. Transmission: Transmission by inhalation of bronchial secretions from infected carrier animals. Hosts: Cattle of all ages. Clinical signs: Incubation period is usually long - 3 to 6 months. Fever Rumen shut-down Severe cough after exercise Arched back Chest pain Distended elbows Extended head and neck Grunting expirations Shallow rapid breathing with fluid sounds Gurgling rales Pleuritic Friction Areas of pulmonary dullness on percussion Mortality up to 70%. Gross lesions: Thickening and inflammation of pleura with fibrin deposits, interlobular edema in one or both lungs. Gray to red hepatization of lungs.
Lumpy Skin Disease Definition: LSD in the classical form is an acute viral disease of cattle characterized by the eruption of variably sized cutaneous nodules, edema of one or more limbs and swelling of the superficial lymph nodes. Etiology: Pox virus which is related serologically to sheep and goat pox viruses. Distribution: Africa, Kuwait, Egypt and Israel Transmission: Insect transmission as well as contact transmission. Hosts: Cattle and buffaloes are the natural hosts. Clinical signs: Incubation period of 4-14 days. Fever - fluctuating up to 107 F - nodules after peak Increased salivation Nasal discharge Skin eruptions Skin nodules at different locations - surrounded by intense congestion Gross lesions: Skin nodules of varying sizes. Thicken masses of skin tissue with a creamy gray color. Some lesions ulcerate. Differential diagnosis: Allergies, screwworm infestations, and cutaneous streptothricosis.
Heartwater Definition: HW is an acute, non-contagious infectious disease of ruminants affecting cattle, sheep, goats, and antelope. It is caused by a rickettsia, Cowdria ruminantium, which is transmitted by the Amblyomma ticks. Etiology: Cowdria ruminantium. Distribution: Important disease of Africa and more recently some of the Caribbean Islands. Hosts: Cattle, sheep, goats, buffaloes, and antelope. The antelope is believed to be very important in Africa. The are several non-ruminant hosts including guineafowl, tortoise, hares, and some amphibians and reptiles that may be important in t he maintenance of C. ruminantium in nature. Of importance in the US, is the fact that cattle egrets are known hosts of the host ticks. Experimentally the white tail deer can be infected with HW. Host ticks: Only Amblyomma ticks are known to carry the infective organism. A. variegatum, "the tropical bont tick" is the most important tick. Two US ticks have been shown to be able to carry the organisms…A. maculatum, "the Gulf Coast tick" and A. cajennense, judging from the name, it is probably a Gulf Coast type tick as well. The Gulf Coast tick is a common parasite of white tail deer in the US. Clinical signs: There are four forms of HW of which the acute form is the most common. The acute form is seen in animals introduced into HW areas, therefore, it might be type we would see in the US. Incubation period - 14-28 days after introduced to HW area. Fever - sudden, high (up to 107 F) Off feed Depression Listlessness Rapid breathing Nervous signs: Chewing movements Twitching of eyelids Protrusion of tongue Circling High stepping gait Standing with legs apart and head down Proceeding to convulsions and death within a week Differential diagnosis: Anthrax, rabies, tetanus, or poisonings (lead, organophosphates)
Screwworms Definition: Infestation by the larvae of the fly, Cochliomyia hominivorax, characterized by maggots feeding deeply down in open wounds. Etiology: Larvae from screwworm fly. Distribution: South American below the sterile fly barrier in Panama. They could easily exist in Florida, Texas or California. Hosts: The larvae will feed in open wounds of all warm-blooded animals. Clinical signs: Infestation start with any open wound even those as small as a tick bite. Common sites are the umbilical cords of newborns and management wounds from dehorning, castration, ear tagging, or branding. Maggots deep within wounds Foul-smelling odor Dark exudate
Maggots may be placed in 70% alcohol and shipped to NVSL for identification.
Hemorrhagic Septicemia Definition: Classic HS is a particular form of pasteurellosis manifested by an acute and highly fatal septicemia in cattle and buffaloes. Etiology: Pasteurella multocida Distribution: Africa, Southeast Asia, China, and India. Often seen at the beginning of the monsoon season after several months of dry weather. Hosts: Cattle and buffaloes Transmission: Direct or indirect (fomite) contact with infected cattle or carriers. Clinical signs: Incubation period of a few hours up to 30 hours. Acute death - within 6-24 hours after first signs Dullness Reluctance to move Elevated temperatures Salivation Nasal discharge Edematous swelling under pharynx to brisket Congested mucous membranes Respiratory distress Collapse and death within 72 hours Rapid disease course, high herd incidences and appearance of edematous swelling is very suggestive of HS. Gross lesions: Generalized hemorrhages, edema and hyperemia. Edema of head, neck, brisket. Blood tinged fluid in thoracic and abdominal cavities. Petechial hemorrhages scattered in tissues and lymph nodes.
Bovine Spongiform Encephalopathy Definition: BSE is a fatal, neurodegenerative disease characterized by alterations in behavior (nervousness, fearfulness, panic, kicking) and locomotion (ataxia in hindlimbs, falling down, difficulty in rising, inability to rise) as well as hy persensitivity to touch, sound or light. Etiology: Prions probably spread through contaminated feeds. Distribution: Great Britain, Northern Ireland, Guernsey, Isle of Man, Switzerland, Republic of Ireland, Jersey, Portugal, and France and sporadically elsewhere in Europe. Several countries due to imported cattle from GB. Hosts: Cattle Transmission: Spread to cattle through contaminated feeds following a change in the rendering practices in GB. Clinical signs: Incubation period - 3.5 to 5 years First behavioral: Act different than usual Nervous Fearful or anxiety Aggressive Panic Kicking Refuse to enter parlor Refuse to go through doorways Apprehensive Hyperesthetic Separate from other cattle on pasture Locomotion changes: Ataxia of hindlimb Difficulty rising Inability to rise Progressively worse signs - 1 week to 1 year: Loss of body condition Reduced ruminal contractions Differential diagnosis: Rabies, hypomagnesemia, ketosis, CNS abscesses, mineral or plant toxicity, listeriosis.
General References: Foreign Animal Diseases. Revised 1992. Committee on Foreign Animal Diseases of USAHA, Suite 114, 1610 Forest Avenue, PO Box K227, Richmond, VA 23288. 804-285-3210, FAX 804-285-3367 Illustrated Manual for the Recognition and Diagnosis of Certain Animal Diseases. 1982. Mexico-United States Commission for the Prevention of Foot and Mouth Disease. USAHA, Suite 205, 6924 Lakeside Avenue, Richmond, VA 23228 Illustrated Manual for the Recognition and Diagnosis of Certain Animal Diseases. Volume 2. 1988. Mexico-United States Commission for the Prevention of Foot and Mouth Disease. Braun U, Pusterla N, Schicker E. Bovine Spongiform Encephalopathy: Diagnostic Approach and Clinical Findings. Compendium 20(10); S270-S278, Oct 1998.
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