Genetic Polymorphisms of Foot-and-Mouth Disease Virus

*Khammadov Nail Ildarovich*

### **Abstract**

The aim of the work is to search for loci of the genome of various types of foot-and-mouth disease virus (FMDV), characterized by the lowest variability, for use as genetic markers in the polymerase chain reaction (PCR) of virus identification. The nucleotide sequences of the genomes of FMDV of types A, Asia-1, C, O, and SAT (1, 2, and 3) were analyzed. When aligning the genomes of isolates of each type of virus, potentially conservative sites were identified. Comparing these loci, different types of the virus have one, the most conserved locus. Subsequent basic local alignment search tool (BLAST) analysis established the correspondence of the conservative locus to the FMDV genome, and primers and a probe were developed to amplify this locus.

**Keywords:** foot-and-mouth disease virus, type, strain, genome polymorphism, PCR

#### **1. Introduction**

The foot-and-mouth disease virus (FMDV) is an RNA virus belonging to the genus *Aphthovirus,* family *Picornaviridae*. The FMDV includes serotypes: A, Asia-1, C, O, and SAT (1, 2, and 3) [1]. The FMDV infection causes ulcerations (vesicles) on the mucous membranes of the tongue, mouth, nares, hooves, and udder. FMDV is highly contagious. One sick animal can spread the infection rapidly to susceptible animals. The virus is released during the incubation period, in exhaled air, milk, urine, feces, sperm, and saliva. And when there are clinical signs of the disease, the virus is also isolated from the vesicular erosive lesions of the mucous membranes and skin [2].

FMDV is pathogenic to more than 100 domestic and wild animal species [3–5]. FMDV also affects humans [6].

The FMD is zoonotic. It can cause mild infection in humans. The virus infiltrates the human body through the mucous membranes. The incubation period (5–10 days) [7] of the disease is characterized by the virus reproduction in the primary focus. At the end of the incubation period, the pathogen spreads through the body (viraemia). In places where the virus enters, skin and mucous membrane blisters are formed. These blisters later transform into ulcers. The clinical manifestation of FMDV in children is more pronounced, and the clinical signs are sometimes similar to intoxication [8].

In addition to the obvious clinical picture, the detection of FMDV actively uses serological and molecular genetic diagnostic methods. For serological diagnostics, the enzyme immunoassay method is deservedly popular [9–13]. Polymerase chain

reaction and virus genome sequencing methods are used for genetic indication of FMD [14, 15]. The historical development of FMDV research covers a wide variety of techniques. In 1960, the use of cell cultures infected with FMDV was mentioned [16]. In 1966, a complement fixation test (CFT) was used to identify the FMDV [17]. The virus neutralization was employed [18] and, in 1979, the ELISA was introduced and currently in use [9, 10, 13]. The present century is also characterized by the active use of genetic analysis of FMDV nucleic acids [19].

The aim of the study is to search for universal conservative genome loci present in all types of foot-and-mouth disease virus, for use as genetic markers for PCR virus detection.
