Malignant Catarrhal Fever (MCF) is a dead disease, which makes th century and killed Hild Romanes, including its occurrence and sheep and other animals. Even though relatively uncommon, it is a dangerous threat to animal health due to the high rate of mortality and because no effective treatment has been found. MCF is caused by numerous herpesviruses and typically results in a devastating loss for agricultural producers.
Here, we talk about the cause, symptoms, transmission, diagnosis, and prevention of MCF, presenting an overview of this significant veterinary illness.
What Is Malignant Catarrhal Fever?
The Malignant Catarrhal Fever typically results in inflammation of inflammation and gastrointestinal tract, the eyeballs, and the nose, commonly in affected animals. Although it may be present in certain species, sickness is more general in the cattle and bison exposed to the gnu or sheep.
MCF is the result of viruses within the Macavirus genus of the herpesvirus family. The two primary types of MCF are:
- Sheep-associated MCF (SA-MCF) – Ovine herpesvirus-2 (OvHV-2).
- Wildebeest-associated MCF (WA-MCF) – Alcelaphine herpesvirus-1 (AlHV-1).
Hosts and Transmission
Reservoir Hosts
- Sheep (for OvHV-2) and wildebeest (for AlHV-1) are the natural carriers.
- These animals normally harbor the virus asymptomatically and serve as reservoirs, shedding the virus via nasal secretions.
Susceptible Hosts
- Cattle
- Bison
- Deer
- Elk
- Water buffalo
These animals are not natural reservoirs and become severely diseased following infection.
How It Spreads
- Transmission is mainly through aerosol droplets or nasal contact with contaminated secretions from infected animals.
- No animal-to-animal transmission takes place among infected susceptible animals; it’s nearly always from the reservoir host.
- Outbreaks frequently develop when susceptible species are housed together with shedding carriers, particularly around lambing or calving time when viral shedding is most prolific.
Clinical Signs and Symptoms
MCF has an incubation period that varies from 10 days to several months, and the clinical course tends to be acute and fatal. The typical symptoms are:
- High fever
- Profuse nasal and ocular discharge
- Keratoconjunctivitis (foggy, inflamed eyes)
- Mouth and nasal erosions
- Swollen lymph nodes
- Diarrhea
- Neurological signs (tremors, incoordination)
- Death, usually within days of onset
In other species, e.g., bison, the disease runs very quickly with nearly 100% mortality.
Diagnosis
Since MCF signs are similar to those of other diseases such as Bovine Viral Diarrhea (BVD), Foot-and-Mouth Disease (FMD), or infectious bovine rhinotracheitis (IBR), laboratory examination is required for a confirmed diagnosis.
Diagnostic Techniques:
PCR (Polymerase Chain Reaction): Identifies viral DNA (OvHV-2 or AlHV-1).
Histopathology: Checks tissue samples for typical inflammation.
Serological Tests: Identifies antibodies in affected animals.
Treatment and Management
Treatment
There is no cure or definite antiviral treatment for MCF. Supportive care can extend life but generally not save it.
Management
Isolation of infected animals to avoid suffering and additional losses.
Euthanasia can be advised in extreme cases.
Prevention and Control
Prevention is the best method of controlling MCF risk, particularly in areas where sheep and cattle share the same area.
Main Preventive Measures:
- Prevent contact between vulnerable species (e.g., cattle, bison) and reservoir hosts (e.g., sheep), particularly during lambing.
- Sheep and cattle segregation housing or grazing facilities.
- Improved farm biosecurity.
- Control and minimize exposure during risk periods (spring lambing season).
Currently, there is no commercial MCF vaccine, although research continues.
Economic and Agricultural Impact
MCF is not prevalent, but when it hits, the economic losses can be severe owing to:
- High mortality rates
- Loss of breeding animals
- Disruption in herd management
- Veterinary and diagnostic expenses
This is especially important in bison farms, where MCF can destroy entire herds because of extreme susceptibility.
Final Thoughts
Malignant Catarrhal Fever continues to be a concern in mixed-species farming operations. While infrequent, its severity and high mortality rate mean that livestock managers need to be concerned. Prevention using species separation and biosecurity is the best course of action. As investigation continues into possible vaccines and improved diagnostic tools, education and management continue to be our best defense against this pernicious disease.
