FMDV introduction

Foot-and-Mouth Disease (FMD) is a highly contagious viral disease that affects cloven-hoofed animals, including cattle, sheep, goats, pigs, and various wild species. Classified as a List A disease by the World Organisation for Animal Health (WOAH), it poses a severe threat to global livestock industries, food security, and livelihoods, causing substantial economic losses due to reduced productivity, trade restrictions, and control costs. Among the seven distinct serotypes of FMD Virus (FMDV)—O, A, C, Asia 1, SAT 1, SAT 2, and SAT 3—the Southern African Territories (SAT) subtypes (SAT 1, SAT 2, SAT 3) are particularly notable for their geographic distribution, genetic diversity, and unique epidemiological characteristics, requiring targeted surveillance and control strategies. 

What are Foot-and-mouth disease SAT subtypes?

SAT subtypes share the core biological features of FMDV, including high contagiousness through respiratory, oral, and contact transmission—infected animals shed the virus in saliva, urine, feces, and milk, and it can survive in the environment and animal products for extended periods. Clinically, infection with SAT subtypes causes fever, as well as blisters and sores on the mouth, feet, nose, and teats, leading to lameness, loss of appetite, reduced milk production, and in severe cases, sudden heart failure in young animals. Subclinical infections are also common, especially in small ruminants, complicating early detection.

The SAT subtypes were first identified in the 1940s in samples from Southern African Territories (now Botswana, Zambia, and Zimbabwe), hence their name. Unlike serotypes O and A, which are globally widespread, SAT 1, SAT 2, and SAT 3 exhibit distinct serological and genetic differences, with no cross-immunity between them or other FMDV serotypes—immunity from infection or vaccination is serotype-specific, limiting the effectiveness of broad-spectrum control measures. SAT 1, SAT 2, and SAT 3 are further divided into multiple topotypes and lineages based on genetic variations: SAT 1 topotypes are numbered using Roman numerals (I to XIII), while SAT 2 and SAT 3 have their own distinct genetic lineages that continue to evolve. Notably, SAT subtypes exhibit higher interserotype sequence diversity and intra-typic variation compared to Eurasian serotypes, posing additional challenges for vaccine development and diagnostic accuracy.

The global distribution of SAT subtypes is primarily centered in Africa, with the African buffalo (Syncerus caffer) serving as their natural reservoir host, maintaining the virus in the wild and facilitating spillover to domestic livestock. SAT 1 and SAT 2 are distributed throughout most of Africa, while SAT 3 is restricted to southern Africa and a small area in eastern Africa. In recent years, SAT 2 has emerged as a growing concern due to its expansion beyond Africa—novel strains have been detected in North Africa (Algeria, Libya, Tunisia) and the Middle East (Iraq, Turkey, Bahrain), driven by livestock movement, international trade, and environmental factors. Africa is divided into three loosely defined FMDV pools (East Africa: Pool 4; West Africa: Pool 5; Southern Africa: Pool 6), with overlaps between Pools 4 and 5, and SAT subtypes circulating within these pools with varying prevalence.

Effective control of SAT subtypes requires a comprehensive, multi-faceted approach tailored to their epidemiological characteristics. Vaccination is a key preventive measure, but it must target the specific SAT serotypes and lineages circulating in a region, as cross-protection between serotypes is absent. The Food and Agriculture Organization (FAO) and WOAH promote the Progressive Control Pathway for FMD (PCP-FMD), guiding countries to adopt risk-based strategies, including robust surveillance, animal movement controls, and strict biosecurity measures to prevent virus transmission through contaminated equipment, clothing, or vehicles. In outbreak situations, culling of infected and contact animals, disinfection of affected areas, and restriction of livestock trade are critical to containing the spread. Additionally, capacity building for veterinary services and enhanced preparedness in high-risk regions, such as the Mediterranean, are essential to respond quickly to emerging outbreaks.

Early detection of Foot-and-mouth disease SAT subtypes

Early and accurate detection is the cornerstone of effective SAT subtype control, as prompt identification of infected animals and virus strains enables timely implementation of containment measures—a critical step given the high genetic variability of SAT subtypes and the challenges of subclinical infections. WOAH/FAO network for foot-and-mouth disease has released the primers for SATs and other subtypes of FMDV, which enables quick and correct identification of the nucleic acid of these infections in different animals. Produced by Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER) in Italy, the IZSLER FMDV SAT ELISA kits are highly specialized solid-phase competitive ELISA tests designed for the detection of antibodies specific to Foot-and-Mouth Disease Virus (FMDV) structural proteins (SP), specifically SAT 1 and SAT 2 serotypes.

Ringbio as the professional manufacturer, have been working on FMDV testing for years, now we have the followingy items for your selections, which include

These kits can be used for Foot-and-mouth disease SAT subtypes testing in different scenarios. The real-time PCR are applicable for testing labs, government testing, etc, while the ELISA kits are readily available for large-quantity sample screening, and the rapid test kits can be used on farms. All these kits together, provide robust, efficient tool to strengthen surveillance, confirm outbreaks promptly, and facilitate trade screening, ultimately supporting global efforts to protect livestock industries and safeguard food security.

Note: this article is drafted with the help of AI.

Further readings

• WOAH, FMDV technical disease cards, https://www.woah.org/en/document/technical-disease-card-fmd/
• FAO, Foot-and-mouth disease, https://www.fao.org/animal-health/animal-diseases/foot-and-mouth-disease/en
• Network for foot-and-mouth disease, WOAH/FAO reference laboratory, Pirbright UK, https://www.foot-and-mouth.org/science/lineage-specific-fmdv-real-time-rt-pcr-assays