· The first ever case of Foot and Mouth Disease appeared in 1957 in New Zealand.
Is Foot and Mouth Disease A Persistent Threat to Global Livestock? As the number of cases and instances is increasing worldwide, the concern is very rightful. Moreover, the humans aren’t aware of diseases in animals until there is some hue about it. The research shows that animals can also be affected with severe pandemics. For instance, a research study in 2020 showed that animals could also contract corona virus. Similarly, animals are able to contract all human diseases. In fact, some researchers claims the intermingling of animals and humans could be a reason of common diseases.
Therefore, we discuss the etymology of Foot and Mouth Disease. The first identified case of hand, foot, and mouth disease (HFMD) was reported in New Zealand in 1957. The characteristic symptoms, including fever and a vesicular rash on hands and feet caused by Coxsackievirus (CV), were first described in Toronto, Canada, in 1957. The term “hand-foot-and-mouth disease” was initially used in 1959 to describe a similar disease with the same symptoms.
Foot and Mouth Disease (FMD) is a highly contagious viral disease that affects cloven-hoofed animals such as cattle, pigs, sheep, goats, and deer. It is caused by the Aphthovirus of the family Picornaviridae. FMD is a major concern for global agriculture due to its rapid transmission, economic implications, and the challenges it poses to trade and animal health. Despite significant progress in disease control in certain regions, FMD continues to persist in many parts of the world, particularly in Africa, Asia, and parts of South America. This article provides a detailed examination of the etiology, transmission, clinical presentation, diagnosis, control strategies, and the broader implications of FMD on global agriculture and economy.
Etiology and Virus Structure
Foot and Mouth Disease is caused by the Foot-and-Mouth Disease Virus (FMDV), which is a non-enveloped, single-stranded RNA virus. The virus is classified into seven serotypes: O, A, C, SAT 1, SAT 2, SAT 3, and Asia 1. Each serotype has multiple subtypes, and immunity to one serotype does not confer protection against others. This antigenic diversity makes vaccine development and immunization efforts particularly challenging.
FMDV is highly resilient in the environment under favorable conditions, particularly in cool and moist climates. It can survive in contaminated materials such as hay, manure, and even on clothing or equipment, contributing to its potential for rapid and widespread dissemination.
Modes of Transmission of Foot and Mouth Disease
FMDV spreads through direct and indirect routes:
Direct Transmission: This includes close contact between infected and susceptible animals. The virus is present in all secretions and excretions, including saliva, milk, urine, and feces.
Aerosol Transmission: The virus can be airborne and spread via aerosols over short distances, and under favorable climatic conditions, even several kilometers.
Fomites: Contaminated vehicles, clothing, footwear, feed, and equipment can act as fomites and play a significant role in long-distance transmission.
Animal Products: Meat and dairy products from infected animals, if not properly processed, can harbor the virus.
Human beings, although not susceptible to FMDV infection, can be mechanical vectors by carrying the virus on their bodies or clothing.
Clinical Signs and Symptoms of Foot and Mouth Disease
The clinical presentation of FMD varies depending on the species, strain of the virus, and the age and immune status of the animal. Common signs include:
- High fever (up to 41°C) at the onset of infection.
- Formation of vesicles (blisters) in the mouth, on the tongue, gums, lips, teats, and between the hooves.
- Lameness due to painful lesions on the feet.
- Drooling and reduced feed intake due to oral lesions.
- Decreased milk production in dairy animals.
In young animals, particularly calves, the virus can cause myocarditis, leading to sudden death. In pigs, lesions in the feet may be more severe, causing reluctance to move and lameness. Morbidity rates can approach 100% in a herd, but mortality is typically low in adult animals.
Diagnosis and Laboratory Confirmation
Due to the similarity of FMD symptoms with other vesicular diseases such as vesicular stomatitis, accurate laboratory diagnosis is crucial. Diagnostic techniques include:
- Virus Isolation: Traditional method using cell culture, but time-consuming.
- ELISA (Enzyme-Linked Immunosorbent Assay): Detects viral antigens or antibodies.
- RT-PCR (Reverse Transcriptase Polymerase Chain Reaction): Highly sensitive and rapid, used for detecting viral RNA.
- Serological Testing: Used to determine past exposure and herd immunity levels.
Rapid diagnosis is essential for implementing timely control measures to contain outbreaks.
Prevention Measures for Foot and Mouth Disease
Control strategies vary depending on whether a country is FMD-free or endemic. The following measures are commonly employed:
- Vaccination: In endemic regions, regular vaccination programs using serotype-specific vaccines are the primary tool for controlling outbreaks. However, vaccine efficacy can be compromised due to antigenic variability and cold chain issues.
- Movement Restrictions: Imposing quarantines and bans on the movement of animals and animal products during an outbreak to prevent spread.
- Stamping Out: In FMD-free countries, the culling of infected and exposed animals is a standard response to outbreaks.
- Biosecurity Measures: Enhancing farm-level biosecurity, including disinfection protocols and controlling access to livestock premises.
- Surveillance and Monitoring: Active and passive surveillance systems to detect early cases and monitor the spread.
- Public Awareness and Education: Training farmers, veterinarians, and stakeholders on early detection and control measures.
Economic Implications of Foot and Mouth Disease
The impact of FMD on the agricultural economy is profound. An outbreak can lead to:
- Loss of productivity in terms of milk yield, weight gain, and reproduction.
- Massive costs associated with culling, disposal, compensation, and vaccination.
- Disruption of domestic and international trade due to imposed bans on exports of animals and animal products.
- Long-term effects on food security and livelihoods, particularly in developing countries where livestock are a primary source of income.
The 2001 outbreak in the United Kingdom is a stark reminder, where over six million animals were culled, and the economic cost exceeded £8 billion, including losses from tourism and related sectors.
Global Efforts and Future Directions
International organizations such as the World Organization for Animal Health (WOAH) and the Food and Agriculture Organization (FAO) are leading global efforts through initiatives like the Global Framework for the Progressive Control of Transboundary Animal Diseases (GF-TADs). These programs aim to improve surveillance, vaccine banks, and emergency preparedness.
Emerging technologies in vaccine development, including recombinant and marker vaccines, promise to enhance control capabilities. Additionally, advances in molecular diagnostics and digital surveillance tools offer improved early detection and response.
Is Foot and Mouth Disease A Persistent Threat to Global Livestock?
Foot and Mouth Disease remains one of the most formidable viral threats to livestock worldwide. While significant strides have been made in controlling and eradicating the disease in some regions, it continues to pose a serious risk in others. The multifaceted challenge of FMD requires an integrated approach combining scientific innovation, international cooperation, and robust policy implementation. Continued investment in research, infrastructure, and farmer education is essential to mitigate the impact of this enduring and economically devastating disease.
