Isolated image of a horse's nose. Horse and Rider magazine online.

Of viruses, zoonotics and horses

A morbillivirus that caused fatal disease in horses and humans

Articles on this subject keep popping up in our news feed on horses, most likely because of the coronavirus pandemic so that any mention of any type of virus is garnering attention.

No need for alarm horse lovers, owners and handlers. The title of the article clearly states “that caused” (past tense), not “is causing” (current tense).

We cite below some information on the morbillivirus for the scientists among us first. Following that we talk about zoonoses (a disease which can be transmitted to humans from animals) associated with horses. Non-scientists please feel free to skip ahead.

In an abstract published by PubMed they state:

Open quote

A morbillivirus has been isolated and added to an increasing list of emerging viral diseases. This virus caused an outbreak of fatal respiratory disease in horses and humans. Genetic analyses show it to be only distantly related to the classic morbilliviruses rinderpest, measles, and canine distemper. When seen by electron microscopy, viruses had 10- and 18-nanometer surface projections that gave them a “double-fringed” appearance. The virus induced syncytia that developed in the endothelium of blood vessels, particularly the lungs.


NCBI tells us:

Open quote

The genus Morbillivirus belongs to the virus family Paramyxoviridae, a group of enveloped viruses with non-segmented, negative strand RNA genomes. It contains viruses that are highly infectious, spread via the respiratory route, cause profound immune suppression, and have a propensity to cause large outbreaks associated with high morbidity and mortality in previously unexposed populations. In populations with endemic virus circulation, the epidemiology changes to that of a childhood disease, as hosts that survive the infection normally develop lifelong immunity.

Measles virus (MV) is the prototype morbillivirus, and causes disease in primates. Read more at NCBI »


Well, we don’t know about you but that was “all Greek” to us.

It is true, however, that animals can sometimes carry harmful germs that can spread to people and cause illness — these are known as zoonotic diseases or zoonoses. Please read on.

Click image to see “Kissing horses — cute or dangerous?” (REDDIT). We are not talking about “exchanging breath” which is normal and natural, especially to a horse.

If you live with, care for or ever have to handle horses, please pay special attention to the bulleted recommendations at the end of the report below.

This is sound advice, and excellent habits to form if you are going to be around horses for any reason. Copy and paste the list into a document, print it out and carry it with you. Post it at your stable, in your barn and/or barn office.

Zoonoses associated with horses

By WASHINGTON STATE UNIVERSITY

This document provides information on various diseases that can be passed from horses to humans. Often these diseases do not make the animal appear sick but can cause serious illness in humans. Persons with specific medical conditions such as an immunodeficiency and pregnancy may be at higher risk of developing disease or complications from a zoonotic disease and should consult with their physician before working with horses. The diseases associated with horses include rabies, ringworm, methicillin-resistant strains of Staphylococcus aureus, leptospirosis, salmonellosis, campylobacterosis, cryptosporidiosis and infections with Rhodococcus equi.

Diseases associated with direct contact:

Rabies is a fatal viral infection that can be transmitted by bites, and mucus membrane exposure from an infected animal. Rabies in horses in the Northwest is very rare but horses can be infected from contact with wildlife such as bats, skunks, and raccoons. Infected animals often exhibit neurological symptoms and unusual behavior. There is an effective vaccine available for people and most domestic animals including horses.

Dermatophytosis is a fungal skin infection commonly known as “ringworm” and is seen in both animals and people as scaly round areas of hair loss. Transmission of ringworm is by direct contact with an infected animal. For prevention, wear gloves when handling infected animals and wash hands after contact.

Methicillin-resistant Staphylococcus aureus (MRSA) has been identified in both normal horses and those with clinical symptoms of wound infections. It is possible to contract the infection through direct contact with an infected horse. Once infected, people may or may not develop symptoms. While transmission is unlikely, it is recommended to wash your hands after handling horses and to cover any open wounds that are susceptible to infection.

Diseases associated with vectors or contaminated materials:

Leptospirosis is most commonly associated with eye infections, abortion or kidney disease in horses and is typically shed in the urine of infected animals. People acquire the infection by oral ingestion and contact with contaminated urine, placenta, and fetal tissues. The organism can infect people through abraded skin.

Rhodococcus equi is a bacterium that causes pneumonia in foals and is found in manure and contaminated soil around horse facilities. Inhalation of dust particles laden with virulent R. equi is the major route of infection. R. equi is an opportunistic pathogen in immunocompromised people and does not cause disease in persons with normal immune function.

Salmonellosis, campylobacterosis, and cryptosporidiosis are acquired by contact and accidental oral ingestion of fecal material from infected animals. Animals infected with these diseases typically have diarrhea but some animals may show no symptoms of disease. Any animal with diarrhea should be suspect of having a zoonotic disease.

Individuals with exposure to animals and animal environments may develop allergic reactions to animal proteins (allergens). Approximately 20-30 percent of individuals working with laboratory animals will develop an allergic reaction to animal proteins and 5-10 percent of individuals will develop asthma. Personnel may be exposed to allergens through inhalation and contact with skin, eyes and mucous membranes. Animal allergens may be present in animal dander, hair, skin, urine, saliva, serum and any contaminated feed or bedding materials. Risk factors for developing an allergic reaction include history of previous allergies to animals. The signs and symptoms of an allergic reaction are nasal discharge and congestion, conjunctivitis, tearing and eye itching, skin redness, rash or hives and lower airway symptoms (coughing, wheezing and shortness of breath).  Individuals with symptoms suggestive of an allergic reaction related to a workplace allergen should report their concerns to their supervisor and consult a physician.

Transmission of zoonotic diseases from horses is primarily by direct contact when handling and grooming horses, contact with contaminated objects such as grooming tools, accidental ingestion of feces or urine or inhalation of aerosolized materials.

We can protect ourselves from most diseases by using the following procedures:

  • Handle animals appropriately and safely to avoid bites, kicks, and other injuries.
  • Thoroughly wash bite wounds and report injuries.
  • Do not eat, drink, apply makeup or use tobacco products while handling horses or in horse stalls or pens.
  • Wash hands after handling animals or their waste both before eating or drinking.
  • Wear clothing appropriate for handling large animals including long pants and shoes or boots that cover your feet (no sandals). Launder the soiled clothing separate from your personal clothes and preferably at the animal facility
  • Wear respiratory protection when appropriate.
  • Keep animal areas clean and disinfect equipment after using it on animals or in animal areas.

Most importantly, familiarize yourself about the animals that you will be working with and the potential zoonotic diseases associated with each species. If at any time, you suspect that you have acquired a zoonotic disease, inform your supervisor and seek medical care.


Thank you for stopping by.

Fund for Horses

Please see also the Fund for Horses’ new website which we launched at the beginning of the year. We keep forgetting to mention it. It is deluxe! It is wonderful for us finally to have all our sites hosted in one place, at the highly recommended WordPress.com.


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