Research Article

A Confirmation of Foot-and-Mouth Outbreaks,Virus Serotypes, and Hematological Alterations in Naturally Infected Sheep in Al-Quba City, Libya

Ahmad Omar Ali
Omar Al-Mukhtar University, Libya
* Corresponding author
Aiman Arheim
Omar Al-Mukhtar University, Libya
Salah Edein Abrayk
Omar Al-Mukhtar University, Libya
Zahra Mohammed
Omar Al-Mukhtar University, Libya
DOI icon 10.24018/ejvetmed.2025.5.4.149

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Submitted 2025-09-09
Published 2025-11-18

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Article Main Content

Foot-and-mouth disease is a viral disease that affects domestic and wild cloven-hoofed animals. This study aimed to confirm FMD outbreaks, identify FMD virus serotypes, and assess the alterations in hematological parameters in affected sheep. A total of 95 sheep were used in this study; 45 sheep were confirmed for FMD, and the other 40 sheep were healthy and used as a control group. Blood samples were collected to establish CBC, and serum samples were collected for FMD virus serotypes identification. Two serotypes were identified by the ELISA test: serotype A and serotype O. Serotype A was more prevalent than serotype O with percentages of 50% and 20%, respectively. The mean values of RBCs, Hb, and PCV were decreased significantly, whereas the mean values of WBC, MCV, and MCH were significantly increased in the affected group. In conclusion, this study confirmed the FMD outbreak and identified the virus serotypes, reporting serotype A in the area, revealing that FMD has induced significant alterations in hematological parameters. These changes could be attributed to anorexia or the disruption of hematopoiesis as a complication of the virus’s virulence.

Keywords: Aphthovirus hematology FMDV serotypes Foot-andmouth disease

Introduction

Foot-and-mouth disease (FMD) is a contagious disease caused by a viral infection [1]. The causative viral agent, Foot-and-mouth disease virus (FMDV), belongs to the family Picornaviridae and genus Aphthovirus. There are seven FMDV serotypes; C, A, O, Asia-1, SAT-1, SAT-2, and SAT-3 [1], [2]. However, only serotypes O, A, and SAT-2 have been identified in Libya [3].

This disease is generally endemic in most developing countries, whereas industrialized countries are free [1], [4]. FMD has been present in Libya for over half a century, and the first periodic outbreaks occurred in 1959 [5]. Furthermore, a massive number of FMD outbreaks occurred in February 2012, and by the end of 2012, Libyan authorities responded with a mass vaccination using inactivated purified vaccine [6].

FMD not only reduces the commercial value of affected animals by body weight loss, wool and milk production, and vaccination costs. However, it is one of the most important diseases limiting the commercial use of animals and their products, both locally and globally [7].

FMD is not fatal in affected sheep [8], [9]. Unlike in cattle, the disease is characterized by clinical signs. In contrast, it is often mild and inapparent in sheep [10]. Sheep with FMD show clinical symptoms including fever, salivation, lameness, anorexia, and the presence of vesicular lesions [8], [11]. Furthermore, Hughes et al., (2002) reported that the only consistently observed lesions in affected sheep with FMD are vesicular lesions, whereas other lesions may not be observed. These lesions occur primarily in the oral cavity, udder, and foot particularly involving both the interdigital cleft and the coronary band region [12]. In some cases in lambs, this disease may induce necrosis in the heart tissue and lead to death before vesicular lesions develop and become visible in common locations [13].

In Libya, small ruminants are the primary source of income for farmers, particularly in the eastern province, where sheep considered the main source of dietary protein. For these reasons, it is important to control any outbreak and implement preventive measures to eradicate FMD in Libya. This study was conducted to confirm FMD outbreaks, identify FMDV serotypes, and evaluate the possible alterations in blood parameters in naturally infected sheep with foot-and-mouth disease in Al-Quba City, Al-Jabal Al-Akhdar region, Libya.

Materials and Methods

Study Area and Animals

This study was carried out in Al-Quba city, which is situated within Al-Jabal Al-Akhdar region of Libya’s eastern province. Al-Quba is located at latitude 32°46 N and longitude 22°15 E with an elevation of 708 meter above sea level. The temperature ranges from 25°C to 27.2°C during the hottest seasons and 8°C to 10°C during the coldest seasons.

From July 2020 to February 2021, a total of 45 local breeds of sheep from five farms with suspected FMD, aged 2–4 years, which had never been vaccinated were used in this study. Forty healthy local breeds from another farm were used as the control group. All sheep were examined for their physical condition and vital signs.

Serological Test

Peripheral blood samples (5 ml) were collected from the jugular vein of each animal by using plain evacuated blood tubes. Samples were centrifuged at 3000 rpm for 20 minutes to obtain serum. Serum was collected from each tube and placed into separate well-labeled tubes. The tubes were sent to the Libyan National Center for Animal Health (NCAH). The NCAH then forwarded them to IZSLER in Brescia, Italy, an OIE/FAO FMD reference laboratory for virus serotype identification. Briefly, the reference laboratory conducted various tests, including a NSP-ELISA for antibody detection against non-structural proteins (NSP), and a series of three competitive ELISAs for the detection and serotyping of antibodies to the structural proteins (SP) of FMDV serotypes O, A, and SAT-2 for the identification of FMDV serotypes [3], [14], [15].

Hematology

Peripheral blood samples (5 ml) were collected from the jugular vein of each animal using evacuated blood tubes containing EDTA for complete blood count (CBC); including red blood cells (RBC), hemoglobin (Hb) concentration, white blood cells (WBC), packed cell volume (PCV) Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), and Mean Corpuscular Hemoglobin Concentration (MCHC). Analysis was performed using a Hematology Analyzer, (Genex, USA).

Statistical Analysis

All data were analyzed using the t-test followed by analysis of variance (two-way ANOVA analysis). The analysis was performed using Statistical Package for Social Sciences (IBM SPSS® Statistics version 27). The hematological results are presented as the mean ± SD, and the level of significance was p > 0.05.

Results

All diseased animals were observed from a distance, and any behavioral changes were recorded (Table I). Diseased sheep were inactive, had anorexia, excessive salivation, preferred not to move or stand, and suffered lameness. The body temperature was elevated in all diseased sheep. Physical examination revealed the presence of small vesicles in the oral cavity and feet.

Animals Age by months Temperature (°C) Salivation Vesicular lesions (number of animals) Lameness Preferred not to stand
Oral cavity Foot
Healthy 24.6 39.04 0 0 0 0 0
Diseased 35.4 41.28 29 29 21 43 20
Table I. Clinical Observations of Healthy and Diseased Animals

Virus Identification

A total of 45 samples were positive for FMD. Two serotypes were identified: serotype A and O. The majority of positive samples were serotype A, followed by serotype O at 50% and 20%, respectively (Table II). In addition, there was no correlation between age and serotype prevalence.

Animals FMDV (Positive) Free of FMDV (Negative)
Serotype A Serotype O
Healthy 0 0 40
Diseased 27 18 0
Table II. Number of Positive and Negative Samples and Detected FMDV Serotypes

Hematology

The hematological parameters of sheep with FMD showed a significant elevation in WBC count, MCV, and MCH values compared to healthy sheep. Moreover, RBC count, Hb, and PCV values were decreased significantly in diseased sheep (Table III). However, the MCHC value from diseased sheep increased but was not significant when compared that to healthy sheep.

Blood parameters Healthy animals Diseased animals
RBCs × 106 9.98 ± 0.10 3.86 ± 0.38*
WBCs × 103 7.54 ± 0.01 44.69 ± 5.88*
Hb (g/dL) 12.23 ± 0.19 9.36 ± 0.39*
PCV (%) 25.68 ± 1.94 18.32 ± 1.36*
MCV (FL) 25.70 ± 1.43 53.13 ± 2.88*
MCH (Pg) 13.31 ± 1.02 24.43 ± 2.72*
MCHC (g/dL) 47.64 ± 3.71 51.33 ± 3.91
Table III. Hematological Parameters in Healthy and Sheep Affected by FMD

Discussion

Foot-and-mouth disease is the most highly contagious viral diseases affecting small ruminants and is therefore regarded as one of the most significant transboundary animal diseases [16]–[18].

The present study demonstrated that most sheep affected by FMDV exhibited fever, inactivity, depression, anorexia, excessive salivation, lameness, and vesicular lesions limited in the mouth and on the feet. These clinical signs are consistent with those reported in many previous studies [11]–[13], [16], [19], [20].

Since the last sporadic outbreaks in Libya in 2012, FMD infection in sheep has been reported but confirmed only clinically by veterinarians. This study is the first, to our knowledge, to identify FMDV serotypes and blood profiles in naturally infected sheep in Libya. Moreover, this study reported that samples submitted for FMDV identification were positive for serotypes O and A. Interestingly, serotype A was more dominant than serotype O, by 50% and 20% respectively. However, during the last sporadic outbreak of FMD, only serotype O was reported in small ruminants in the area of Al-Jabal Al-Akhder, where the city of Al-Quba is located [3]. Therefore, this study is the first to report FMDV serotype A in the Al-Jabal Al-Akhder region.

Previous studies have reported different hematological findings, such as a significant increase in WBC count and MCV values, along with a significant decrease in the RBC count [21]–[24]. In contrast, other studies demonstrated a significant increase in PCV percentage with no significant changes in RBC, MCV, MCH, MCHC, and WBC values [25], [26]. In this study, we reported a significant reduction in RBC count, Hb, and PCV values, accompanied by a significant increase in WBC count, MCV, and MCH values when compared with the results from healthy animals. Our results are corroborated by some of the previous studies but disagree with others. The significant increase in MCV and MCH values suggests macrocytosis; a hematological condition in which RBCs become abnormally large [27]. The interpretation of our findings in this study regarding the reduction in RBC count, Hb, and PCV could be attributed to anorexia or a complication of the virulence of the virus strain that led to hemolysis hematopoietic disorder, or endocrinopathy; suggesting further investigation in the future studies.

Conclusion

This study investigated the Foot-Mouth-Disease outbreaks in small ruminants (sheep) that occurred in the area of Al-Quba city, Libya, until the outbreaks stopped, and it has provided reliable and new findings regarding FMDV subtypes, morbidity, mortality, and economic impacts. It can also be concluded that FMDV (serotypes A and O) causes macrocytic anemia accompanied by significant alterations in blood parameters in affected sheep. These effects lead to poor health and significant economic losses in animals.

Conflict of Interest

The authors declare that they do not have any conflict of interest.

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