Animal Diseases – Multiple species
Equine/Horse, Rabbit, Primate, Camel

African horse sicknessTop

Overview
African horse sickness is a noncontagious, vector-transmitted disease affecting all species of equidae (mainly horses, mules, donkeys, and zebras). While the disease is usually fatal in horses, other equine species and their crossbreds may display only mild clinical signs.

AHS is endemic in the central African regions. Outbreaks in Europe have occurred in Spain (1987–1990) and Portugal (1989). The spread of the disease depends on the occurrence of its main vector, Culicoides spp.

Signs
Clinical signs of AHS are fever, hemorrhage, and edema of subcutaneous tissues, lungs, and heart. As the characteristics and clinical signs of the disease can easily be confused with those of other diseases, laboratory diagnosis of AHS is very important.

Human health risk
It does not appear that African horse sickness presents a zoonotic risk.

Economic impact
The mortality rate for horses infected with the disease is 70% or greater. Economic consequences could be substantial and long-lasting if an outbreak of African horse sickness were to occur in North America or Europe, where the horse industries are multi-billion dollar industries.

Clostridium perfringensTop

Overview
A spore-forming, anaerobic bacterium, Clostridium perfringens is commonly found in the soil and digestive tracts of various domestic animals, and is categorized into six unique types (A, B, C, D, E, and F), with Type-B, -C, and -D being the most common forms of the disease.

It is not uncommon for small amounts of C. perfringens to inhabit and pass through the digestive tract of an animal without causing disease. But in instances where an animal is exposed to a sudden increase in carbohydrates (milk, supplementary concentrates, etc.) C. perfringens can rapidly increase in numbers, producing large amounts of toxin that often cause rapid death.

Type-B, also known as lamb dysentery, presents a high mortality rate in young lambs and is also linked to disease in young calves.

Type-C typically affects cattle, small ruminants, and swine, where it can contribute to hemorrhagic and necrotic enteritis.

Type-D, also known as “pulpy kidney disease” or "overeating disease,” is associated with small ruminants and cattle. C. perfringens Type-A and -C can also cause enterocolitis (swelling of the small and large intestines) in foals, where stock-horse breeds such as quarter horses are more susceptible.

Signs
Clinical signs are usually absent with animals that were healthy several hours prior and then suddenly found dead. Because of the aggressive nature of the disease, and rapid onset of death, it can be challenging to observe clinical signs in an infected animal. Upon closer examination of an animal prior to death, C. perfringens may present a variety of signs such as excitement, circling, headpressing, convulsions, listlessness, diarrhea, colic or a disinterest in nursing.

Human health risk
It does not appear that C. perfringens presents a zoonotic risk.

CryptosporidiosisTop

Overview
Cryptosporidiosis is caused by microscopic intestinal parasites that are excreted in the feces of an infected animal. Found throughout the world, the parasites commonly interact with other enteropathogens to produce diarrhea and intestinal injury in neonatal farm animals such as piglets, kids, lambs, and foals.

Studies have shown that concurrent infections with other pathogens such as coronavirus and rotavirus can result in more severe diarrhea. While mortality rates in cryptosporidiosis are usually low, fatalities can occur when complicated by other factors such as an animal experiencing energy deficit as a result of low colostrum/milk intake, concurrent infections, or chilling caused by adverse weather conditions.

Transmission of the disease may occur directly from animal to animal, or indirectly from environmental contamination, fecal contamination (water or feed supply), or human transmission. Infection in calves can be detected at as early as 5 days of age, with diarrhea occurring between 5–15 days of age.

In small ruminants, infection can be associated with severe outbreaks of diarrhea, resulting in high mortality rates in lambs 4–10 days of age, and goat kids 5–21 days of age.

Although cryptosporidiosis is not generally regarded as an important enteric pathogen in swine, infections can be seen over a broader age range (1 week of age up to market age), and can contribute to post-weaning malabsorptive diarrhea in infected swine.

Cryptosporidiosis is less prevalent in foals, but when infection does occur it is typically at 5–8 weeks of age.

Signs
Signs of cryptosporidiosis can include diarrhea that persists for several days, significant weight loss, emaciation, apathy, anorexia, and dehydration.

Human health risk
Cryptosporidium can be a common nonviral cause of diarrhea in immunocompetent persons (e.g., children) and can have a severe health impact on immunocompromised persons. Infected animals can transmit the disease directly to humans, and there is also a risk of the cryptosporidiosis being transmitted through surface and drinking water that has been contaminated with the feces of an infected animal.

Equine arteritis (EAV)Top

Overview
EAV is an enveloped single-stranded, positive-sense RNA virus that primarily affects equine populations, with the highest occurrence of the disease appearing in warmbloods and standardbreds. With the exception of Iceland and Japan, EAV is a global disease and has been associated with an increased number of laboratory-verified outbreaks in recent years. Outbreaks of EAV are commonly linked to transport of infected animals or shipment of semen that is contaminated with the virus.

EAV is primarily transmitted via the respiratory route and in environments where naive equids may be kept in close contact, such as shows, breeding farms, racetracks, and veterinary hospitals. Mares can also be infected venereally after breeding to a carrier stallion, either by live cover or artificial insemination. Additionally, the infection can be transmitted through indirect contact via the hands or clothing of animal handlers, or through fomites contaminated by the virus (e.g., shanks, breeding equipment, twitches, etc.).

Signs
Signs of the disease can differ greatly from one animal to the next and may include persistent fever, limb edema, depression, leukopenia, and anorexia. While less common, infected animals may also show signs of conjunctivitis, nasal discharge, photophobia, lacrimation, stiffness of gait, dyspnea, diarrhea, icterus, ataxia, and edema (supraorbital, periorbital, or ventral body wall).

Human health risk
It does not appear that EAV presents a zoonotic risk.

Economic impact
EAV can contribute to abortion in susceptible mares, and a large percentage of stallions can become carriers of the disease. Since carrier stallions have the potential to transmit EAV very efficiently via natural breeding or artificial insemination, the economic implications for the breeding industry can be significant.

Regulatory requirements vary by country; products may not be available in your geographic area.

Equine viral rhinopneumonitisTop

Overview
The equine herpesvirus 1 (EHV-1) and equine herpesvirus 4 (EHV-4) viruses affect horse populations worldwide and produce acute respiratory disease that is characterized by tracheobronchitis and rhinopharyngitis. Horse population and immune status determine the distribution (age, season, geography) of the virus, but outbreaks of respiratory disease from EHV-1 and EHV-4 will typically first occur in foals within the first weeks or months of their lives. Recurrent clinically apparent infections can be seen in weanlings, yearlings, and young horses, particularly when there is a commingling of horses from different sources.

EHV-1 may cause abortion in mares several weeks to months after infection with the virus, and infection may also contribute to the birth of weak, nonviable foals, or neurologic disease such as equine herpesvirus myeloencephalopathy (EHM).

EHV-1 and EHV-4 are commonly transmitted via indirect or direct contact with nasal secretions or aerosolized secretions from coughing horses infected with the virus. EHV-1 may also be transmitted through contact with aborted fetuses, placentas, or placental fluids.

Documented outbreaks of EHV-1 have shown increased morbidity and mortality rates since 2000 and have resulted in the USDA designating the neurologic form of EHV-1 as an emerging disease.

Signs
Typical signs for EHV may include malaise, cough, nasal discharge, fever, neutropenia, and lymphopenia. Outbreaks with specific strains of EHV-1 can result in neurological disease, with an infected animal displaying a variety of clinical signs such as incoordination, loss of bladder function, loss of skin sensation, and posterior paralysis that could progress to quadriplegia and death.

Human health risk
It does not appear that EHV presents a zoonotic risk.

Economic impact
The economic impact of EHV on the multi-billion dollar horse industry can be significant. In addition to the loss of valuable racing, competition, and recreational horses that may die as a result of EHV, the disease can also contribute to other financial burdens such as treatment costs, quarantines, disease prevention, and an inability of horses to compete in events.

West Nile virusTop

Overview
West Nile virus (WNV) can cause inflammation of the brain and spinal cord lining (meningitis) or inflammation of the brain (encephalitis), and is a mosquito-borne virus. Outbreaks of the virus have been reported in various regions, including Africa, Egypt, Asia, Europe, Australia, and the United States.

Of horses bitten by a carrier mosquito, one-third will typically develop severe disease that will result in death or require the animals to be euthanized. In some instances, gestating foals may become infected with the virus if WNV should cross from the mother’s placenta.

Signs
Signs of WNV may include listlessness, limb weakness, stumbling, droopy eyelids or lower lip, difficulty defecating or urinating, skin twitching, and muscle tremors. In some cases the infected animals may also show signs of fever, seizures, and blindness.

Human health risk
While WNV cannot be transmitted from horses to humans, humans are at risk of being infected with the virus if bitten by a carrier mosquito.

Economic impact
The economic impact of WNV can be significant. In addition to horses that may die as a result of WNV, the disease can also contribute to other financial burdens such as treatment costs, quarantines, disease prevention, and an inability of the animal to be used during its recovery period.

Regulatory requirements vary by country; products may not be available in your geographic area.

Rabbit hemorrhagic disease virus (RHDV)Top

Overview
RHDV causes rabbit hemorrhagic disease (RHD) in adult European rabbits. Since it was first reported in China during the early 1980s, the virus has quickly spread worldwide and is considered endemic in a number of countries. RHD contributes to a high mortality rate in domestic and wild adult animals, with death typically occurring between 48 and 72 hours post-infection. The disease is often associated with necrotizing hepatitis, but it is not uncommon for hemorrhage to be found in the kidneys, lungs, and heart.

There are several potential transmission routes for the disease, including nasal, oral, parenteral, and conjunctival. Since infected rabbits may secrete or excrete viral particles, RHDV can be transmitted through direct contact with an infected animal, or indirectly via contaminated water, food, bedding, equipment, or clothing. There is also a potential for vector-borne transmission of the disease via scavenging insects, birds, and mammals.

Signs
In the peracute form of the disease, rabbits die suddenly and display no obvious clinical signs prior to death. Acute RHDV infections are associated with a variety of clinical signs that may include apathy, anorexia, excitement, paralysis, bloody nasal discharge, ocular hemorrhage, shortness of breath (dyspnea), and inflammation of the trachea (tracheitis).

Human health risk
It does not appear that RHDV presents a zoonotic risk.

Tuberculosis (Tb)Top

Overview
Bovine tuberculosis (Tb) is a respiratory disease caused by the bacterium Mycobacterium bovis. It is a major infectious disease found worldwide in domestic animals, particularly cattle, as well as in certain wildlife populations.

Airborne transmission is the primary pathway for infection of M. bovis within and between species; however, animals may also become infected if they ingest large quantities of the bacterium.

Signs
Tb is predominantly a respiratory disease affecting the lungs and associated lymph nodes. Infection is often subclinical, while clinical signs, when present, are not specifically distinctive of the disease. Symptoms may include physical weakness, anorexia, emaciation, enlargement of lymph nodes, and coughing, particularly in advanced cases of Tb.

Human health risk
Bovine tuberculosis is a significant zoonosis and presents a serious health risk to humans. The bacterium can be spread from animals to humans through aerosols, or through the consumption of unpasteurized milk or dairy products from infected cows.

Economic impact
An outbreak of bovine tuberculosis may have a significant negative impact on the farming industry as a result of reduced milk yields, culling of herds, and restrictions on meat exports from affected areas.

Regulatory requirements vary by country; products may not be available in your geographic area.

Rift Valley fever (RVF)Top

Overview
Rift Valley fever (RVF) is categorized as a bunyavirus and is an acute zoonotic disease that affects ruminants throughout the Arabian Peninsula, Africa, and Madagascar. During periods of epidemic, high abortion and mortality rates can occur among young animals, and humans will often experience an influenza-like disease.

RVF may be transmitted by the movement of animals infected with the virus or by various species of wind-borne mosquitoes. Instances of RVF generally reach their peak during summer, and at the sign of first frost, insect vectors and the disease will typically disappear. In warmer regions, the disease and vectors may be present year-round.

Signs
Common signs of RVF may include lethargy, fever, unwillingness to feed, abdominal pains, jaundice, and diarrhea. In some cases, abortion may be the only sign of infection that an animal displays.

Human health risk
It is possible for humans to be infected with RVF via contact with infected animal tissue or aborted fetuses, mosquito bites, or blood aerosols generated during the slaughter of an infected animal.