Model Answer
0 min readIntroduction
Foot and Mouth Disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals, including ruminants like cattle, sheep, and goats. It’s characterized by fever and blister-like lesions in the mouth, on the feet, and in the interdigital spaces. FMD poses a significant threat to livestock industries globally, causing substantial economic losses due to reduced productivity, trade restrictions, and control measures. The disease is a reportable disease under the Prevention and Control of Infectious and Communicable Diseases Act, 2017, highlighting its importance to national animal health security. Recent outbreaks in India (2023) have underscored the need for robust prevention and control strategies.
Etiology of Foot and Mouth Disease
FMD is caused by the Foot and Mouth Disease Virus (FMDV), belonging to the Aphthovirus genus within the Picornaviridae family. There are seven serotypes (O, A, C, Asia-1, Asia-2, G, and J), each with numerous topotypes. The virus is small (22-30 nm), non-enveloped, and has a single-stranded RNA genome. Genetic variability within serotypes is high, complicating vaccine development and control efforts. Transmission occurs through direct contact with infected animals, aerosols (short-range), contaminated feed/water, and fomites (vehicles, equipment).
Clinical Findings in Ruminants
The clinical signs of FMD vary depending on the animal’s age, immune status, and the virus serotype. Common signs include:
- Fever: A sudden rise in body temperature (typically 39.5°C - 42°C).
- Oral Vesicles: Blisters develop in the mouth, tongue, and pharynx, causing painful salivation (frothing).
- Foot Lesions: Vesicles appear on the interdigital spaces (between toes) and coronary band. These lesions rupture, leading to lameness.
- Nasal Discharge: Serous or mucopurulent nasal discharge.
- Loss of Appetite: Affected animals refuse to eat due to oral pain.
- Reduced Milk Production: In lactating animals, milk yield significantly decreases.
- Deformities: Severe cases can lead to permanent hoof deformities.
Young animals are often more severely affected and may experience higher mortality rates. Clinical signs can be subtle or absent in some animals, leading to asymptomatic spread.
Diagnosis of Foot and Mouth Disease
Diagnosis relies on a combination of clinical suspicion, epidemiological history, and laboratory confirmation.
- Clinical Examination: Characteristic lesions are highly suggestive, but differentiation from other vesicular diseases (e.g., hog cholera, vesicular stomatitis) is crucial.
- Viral Isolation: The virus can be isolated from vesicle fluid or tissue samples using cell culture techniques.
- RT-PCR (Reverse Transcription Polymerase Chain Reaction): A highly sensitive and specific molecular test to detect viral RNA.
- Serological Tests: ELISA (Enzyme-Linked Immunosorbent Assay) and virus neutralization tests are used to detect antibodies against FMDV. These are useful for epidemiological surveillance.
- Differential Diagnosis: Must rule out diseases like Vesicular Exanthema, Swine vesicular disease, Bovine viral diarrhea.
| Diagnostic Method | Advantages | Disadvantages |
|---|---|---|
| Viral Isolation | Confirms presence of live virus | Time-consuming, requires specialized facilities |
| RT-PCR | Rapid, highly sensitive | Requires trained personnel and equipment |
| ELISA | Relatively simple, high throughput | Detects antibodies, not the virus itself |
Control of Foot and Mouth Disease
Control measures are multifaceted and require a coordinated approach:
- Vaccination: Vaccination is a cornerstone of FMD control. Polyvalent vaccines (containing antigens from multiple serotypes) are used. However, due to the virus's genetic variability, vaccines need to be regularly updated. India's FMD control program uses inactivated vaccines.
- Biosecurity: Strict biosecurity measures are essential to prevent virus spread. This includes:
- Restricting animal movement
- Disinfecting vehicles and equipment
- Controlling access to farms
- Implementing quarantine protocols for new animals
- Movement Restrictions: Movement of animals and animal products from infected areas is restricted to prevent further spread.
- Culling: In severe outbreaks, culling of infected and in-contact animals may be necessary to eradicate the virus.
- Surveillance and Monitoring: Active surveillance programs are crucial for early detection and rapid response.
- Public Awareness: Educating farmers and the public about FMD and its prevention is vital.
- International Cooperation: Collaboration with neighboring countries is essential for preventing transboundary spread.
The National FMD Control Programme in India aims to progressively reduce the incidence of FMD through vaccination and improved biosecurity practices.
Conclusion
Foot and Mouth Disease remains a significant challenge to the livestock industry. Effective control requires a comprehensive approach integrating vaccination, stringent biosecurity measures, rapid diagnosis, and international cooperation. Continuous monitoring of virus evolution and adaptation of control strategies are crucial for maintaining disease-free status and safeguarding the livelihoods of farmers. The recent outbreaks in India highlight the need for enhanced surveillance and public awareness to mitigate the impact of this devastating disease.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.