Elsevier

Veterinary Microbiology

Volume 208, September 2017, Pages 89-93
Veterinary Microbiology

Short communication
Molecular characterization of circulating Foot and mouth disease virus (FMDV) serotype O topotype EA-3 and serotype A (African topotype) genotype IV in Egypt, 2016

https://doi.org/10.1016/j.vetmic.2017.07.018Get rights and content

Highlights

  • FMDV outbreaks affecting non-vaccinated animals appeared in severe and mild forms.

  • We characterized two strains (serotype O EA-3 and Serotype A Genotype IV).

  • The detected strains clustered in separate clades, indicating new incursions.

  • The most closely related strains were originated from Sudan.

Abstract

In January–April 2016, cattle and buffalo farm owners and veterinarians reported clinical signs suggestive of foot and mouth disease virus (FMDV) outbreaks among non-vaccinated cattle and buffalo herds in Egypt. The clinical disease observed was either mild (small oral lesions and speedy recovery) or severe (extensive oral lesions and/or mortalities), and the form of the disease (either mild or severe) segregated by farm. This study aimed to confirm the presence of FMDV and to characterize the circulating strains associated with the outbreaks. Vesicular epithelia were collected from 41 animals representing 15 affected cattle and buffalo farms in five governorates (Behira, Cairo, Daqahlia, Giza and Ismailia), and tested by real time (rt) RT-PCR. Consequently, 92% (38/41) of examined samples were positive. Furthermore, the VP1 coding region of 60% (23/38) of positive specimens were amplified by RT-PCR and sequenced. The phylogenetic analysis identified two distinct strains characterized as serotype O topotype EA-3 and serotype A (African topotype) of genotype IV in the severe and mild disease forms, respectively. The newly identified strains clustered in distinct clades in the phylogenetic trees, indicating the likelihood of new incursions into Egypt. Those strains were most closely related to previously described Sudanese strains.

Introduction

Foot and mouth disease (FMD) is a contagious viral disease affecting cloven hoofed animals. The disease causes severe economic loss due to reduced production, deaths in newborn animals, expensive control measures, and restricted animal and meat movement between countries (Knight-Jones and Rushton, 2013).

The foot and mouth disease virus (FMDV) genome is positive-sensed, single-stranded RNA and belongs to the family Picornaviridae, genus Aphthovirus (Grubman and Baxt, 2004). The virus has a spherical structure of about 20–30 nm in diameter and a genome length of 8.4 kb. FMDV is characterized by genetic and antigenic diversity (Domingo et al., 2003), resulting in classification of the virus into seven distinct serotypes (O, A, C, Asia 1, SAT1, SAT2 and SAT3). The serotypes are further delineated into clades (topotyes) based on the sequence analysis of the VP1 structural protein gene, which reflects genetic, antigenic and geographical relationships among the strains (Knowles and Samuel, 2003).

The history of FMDV in Egypt goes back to 1950, with the first reported outbreak caused by serotype SAT2. Following which, a series of outbreaks took place from 1970 until 2006, predominantly caused by serotype O, with a few exceptions of serotype A (Ahmed et al., 2012). In 2006, widespread outbreaks of serotype A affected 24 out of the 27 governorates in the country (Knowles et al., 2007). The SAT2 serotype was re-introduced in 2012, after 62 years of absence from the country. The estimated reduction in calf crop numbers in 2012 was 18% with a mortality rate of 16% as a result of this re-introduction (Ahmed et al., 2012). Serotypes O, A and SAT2 have been detected in the country since 2013, with Serotype O considered to be the predominant serotype (http://www.wrlfmd.org/fmd_genotyping/africa/egy.htm).

Currently, the bovine population in Egypt is estimated at 8.8 million head, divided equally between cattle and buffalo. In 2016, the importation of live cattle increased by 30% to reach 220,000 head compared to 2015 to face a shortage in meat production. In 2015/2016, the main suppliers for live cattle to Egypt were Sudan, Ethiopia, Uruguay, Ukraine, Hungary and Australia (Hamza, 2015). The majority of the cattle population in Egypt (61%) are in small herds of five animals or less, while 25% are in herds of 10 or less. This exacerbates the impact of FMDV in Egypt, because small farmers have less access to vaccines and veterinary services (Hamza, 2012). In 2013, Egypt mandated vaccination of all cattle and buffalo using the locally developed trivalent vaccine containing serotypes A, O, and SAT2 for a subsidized cost of ∼$9/head per year (Hamza, 2015).

During 2016, FMDV outbreaks occurred in non-vaccinated cattle and buffalo herds. The disease varied in severity, with severe outbreaks characterized by extensive vesicular lesions and/or mortalities, while the mild outbreaks manifested as small vesicular lesions, fast recovery and absence of mortalities. Severe and mild forms occurred in both cattle and buffalo, but the form observed segregated by farm. Therefore, this study aimed to investigate the molecular epidemiology of FMDV strains associated with the outbreaks.

Section snippets

Material and methods

Between January to April of 2016, 15 non-vaccinated cattle and buffalo herds in five governorates (Behira, Cairo, Daqahlia, Giza and Ismailia) (Fig. 1) reported outbreaks consistent with FMDV. The farm owners requested the study investigators for technical support. The study team visited the affected farms and conducted clinical examination of a subset of the affected animals. Vesicular epithelia were collected from 41 affected animals from affected farms (Table 1), and transported to the

Results

The 15 investigated farms are located within the five governorates (Behira, Cairo, Daqahlia, Giza and Ismailia) in Egypt. None of the farms vaccinated their animals against FMDV and all farms reported recent introduction of newly purchased animals from local markets prior to the onset of the outbreak. Among the affected animals, clinical symptoms varied in severity between mild and severe manifestations. However, the severity of the manifestations did not vary on each farm; all affected animals

Discussion

The multiplicity of reports of FMDV outbreaks in Egypt identifies a significant breach in disease control and prevention in the country. Despite the presence of a locally developed trivalent vaccine against serotypes A, O and SAT2, annual outbreaks are usually associated with animal trafficking throughout the country. Our data identified two FMDV strains circulating in cattle and buffalo herds in Egypt, 2016. The phylogenetic analyses clustered the strains in serotype O topotype EA-3 and

Conclusion

This study characterized two widespread FMDV strains in Egypt, 2016. The identified strains belong to serotype O topotype EA-3 and serotype A African topotype genotype IV. Those strains were closely related to Sudanese strains. The study displays the continuity of FMD introduction to the Egyptian market despite the control efforts, suggesting further stringency on animal movement and vaccine distribution.

Acknowledgments

The authors would like to thank Mohamed Shafek and Osama Abo-soliman for assisting in sample collection. This research did not receive any support from any funding agencies.

References (20)

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