Seroprevalence and Associated Risk Factors of Foot and Mouth Disease in Cattle in West Shewa Zone, Ethiopia

Sero-Prevalence of Foot-and-Mouth Disease in Cattle in Selected Districts of Jimma Zone, South-Western Ethiopia

BACKGROUND

Foot-and-mouth disease (FMD) is highly contagious and results in a high economic loss in the world.

METHODS

A cross-sectional study was conducted from December 2021 to June 2022 in three selected districts to determine the sero-prevalence of FMD. A total of 384 cattle sera samples were collected and tested for antibodies against FMD virus using FMD NSP c-ELISA.

RESULTS

The overall sero-prevalence of 25.3% was determined. Sero-prevalence of 31.0%, 32.37% and 4.5% was seen in the districts. Higher sero-prevalence was observed in Limmu Seka, and the disease was statistically significant in both Limmu Kosa and Limmu Seka districts (p < 0.05). Higher sero-prevalence was seen at Ambabesa Sadeka Peasant Association (42.86%). However, except Ambabesa Sadeka peasant association (PA), there was no statistically significant association (p > 0.05) of FMD occurrence among the nine PAs. Higher sero-prevalence was recorded in females (33.65%), old age (39.1%), poor body condition (43.0%) and herd size (43.1%). Therefore, sex, age, body condition of the animals and herd size showed significant association (p < 0.05) in the occurrence of FMD in the study areas. Purchased animals were highly infected (56.4%), and there was also a statistically significant association in the origin of the animals (p < 0.05).

CONCLUSION

Overall, FMD is an economically important disease in the study areas.

RECOMMENDATION

Further studies are warranted to characterize FMD virus serotypes in the areas and investigation in wildlife and small ruminants is needed to determine their roles in FMD virus maintenance and transmission.

Seroprevalence and serotype distribution of foot and mouth disease virus and associated risk factors in cattle across various export livestock sourcing districts of Bale Zone, Ethiopia

BACKGROUND

Foot and mouth disease (FMD) is a contagious and economically important viral disease affecting cloven-hoofed animals. A cross-sectional study was conducted from January to March 2022 in selected districts of Bale zone, Ethiopia to determine the seroprevalence and serotypes of FMD virus circulating in cattle. Blood samples were collected from cattle and tested for antibodies against non-structural proteins (NSP) of FMD virus using a 3ABC enzyme-linked immunosorbent assay (ELISA). Positive samples were further tested for serotype-specific antibodies using solid phase competitive ELISA (SPCE). Descriptive statistics, both univariable and multivariable logistic regression were used to analyse FMD serostatus and associated risk factors.

RESULTS

A total of 962 cattle sera were tested and 200 samples, 20.8% (95% CI: 18.3-23.5) were positive for antibodies against NSP of the FMD virus. The highest seroprevalence was observed in the Seweyna district (35.2%, 95%CI: 26.8-44.7) and the lowest in the Dinsho district (13.0%, 95% CI: 9.5-17.5). The seroprevalence of FMD virus antibody was significantly associated with district (P < 0.05). The seroprevalence among different age groups was statistically significant (P < 0.05). The odds of FMD infection for males was 0.76 (95% CI: 0.534-1.082) compared to females, indicating that male cattle have a lower risk for FMD infection. Out of 200 samples tested for serotype O, A, SAT 1, and SAT 2, 85(43%) were found to have serotype O, 59(30%) serotype A, 142(71%) serotype SAT 1, and 75 (38%) serotype SAT2. Furthermore, multiple FMD serotypes were observed in 15-40% (30-80) of animals tested.

CONCLUSIONS

Serotype-specific antibodies against the FMD virus indicate the occurrence and distribution of serotypes O, A, SAT1, and SAT2 in cattle across various districts of the Bale zone in Ethiopia. These findings also highlight the importance of continuously monitoring the seroprevalence of FMD virus serotypes circulation in export livestock sourcing areas. The results indicated that four FMD virus serotypes were distributed across the studied districts. This study supports the inclusion of all four FMD serotypes in vaccine production.

The Pathogenesis of Foot-and-Mouth Disease Virus Infection: How the Virus Escapes from Immune Recognition and Elimination

Foot-and-mouth disease virus (FMDV) is a highly contagious and economically devastating pathogen that affects cloven-hoofed animals worldwide. FMDV infection causes vesicular lesions in the mouth, feet, and mammary glands, as well as severe systemic symptoms such as fever, salivation, and lameness. The pathogenesis of FMDV infection involves complex interactions between the virus and the host immune system, which determine the outcome of the disease. FMDV has evolved several strategies to evade immune recognition and elimination, such as antigenic variation, receptor switching, immune suppression, and subversion of innate and adaptive responses. This review paper summarizes the current knowledge on the pathogenesis of FMDV infection and the mechanisms of immune evasion employed by the virus. It also discusses the challenges and opportunities for developing effective vaccines and therapeutics against this important animal disease.

A review of foot-and-mouth disease in Ethiopia: epidemiological aspects, economic implications, and control strategies

Foot-and-mouth disease (FMD) is a contagious viral disease that affects the livelihoods and productivity of livestock farmers in endemic regions. It can infect various domestic and wild animals with cloven hooves and is caused by a virus belonging to the genus Aphthovirus and family Picornaviridae, which has seven different serotypes: A, O, C, SAT1, SAT2, SAT3, and Asia-1. This paper aims to provide a comprehensive overview of the molecular epidemiology, economic impact, diagnosis, and control measures of FMD in Ethiopia in comparison with the global situation. The genetic and antigenic diversity of FMD viruses requires a thorough understanding for developing and applying effective control strategies in endemic areas. FMD has direct and indirect economic consequences on animal production. In Ethiopia, FMD outbreaks have led to millions of USD losses due to the restriction or rejection of livestock products in the international market. Therefore, in endemic areas, disease control depends on vaccinations to prevent animals from developing clinical disease. However, in Ethiopia, due to the presence of diverse antigenic serotypes of FMD viruses, regular and extensive molecular investigation of new field isolates is necessary to perform vaccine-matching studies to evaluate the protective potential of the vaccine strain in the country.

Factors associated with foot-and-mouth disease seroprevalence in small ruminants and identification of hot-spot areas in northern Nigeria

Many small ruminants infected with foot-and-mouth disease (FMD) remain asymptomatic, with the capacity to promote silent viral spread within domestic and wildlife species. However, little is known about the epidemiological role played by small ruminants in FMD. In particular, there are few studies that examine FMD seroprevalence, spatial patterns and risk factors for exposure in small ruminants. A cross-sectional study was conducted in northern Nigeria (Bauchi, Kaduna, and Plateau States) to determine the true seroprevalence of FMD in backyard small ruminants, identify factors associated with FMD seroconversion at animal and household levels, and identify spatial patterns for FMD virus exposure. Data on animal (n = 1800) and household (n = 300) characteristics were collected using a standardised questionnaire. Sera samples from 1800 small ruminants were tested for antibodies against non-structural proteins of FMD virus. True seroprevalence was estimated stochastically to account for variability and uncertainty in the test sensitivity and specificity previously reported. Risk factors for FMD seropositivity were identified at animal and household levels and spatial patterns were determined. The overall true seroprevalence for FMD virus, in the small ruminant population tested, was estimated to be 10.2 % (95 % Credible Interval (CrI) 0.0-19.0), while State-level estimates were 17.3 % (95 % CrI 0.0-25.8) for Kaduna, 6.9 % (95% CrI 0.0-15.8) for Bauchi, and 3.6 % (95 % CrI 0.0-12.6) for Plateau. State and species were the main risk factors identified at animal level, with interaction detected between them. Compared to goats in Plateau, the odds of testing positive were higher for goats in Bauchi (Odds Ratio (OR)= 1.83, 95 % CI 1.13-2.97, p = 0.01) and Kaduna (OR=2.97, 95 % CI 1.89-4.67, p < 0.001), as well as for sheep in Plateau (OR=3.78, 95 % CI 2.08-6.87, p < 0.001), Bauchi (OR=1.61, 95 % CI 0.91-2.84, p = 0.10), and Kaduna (OR=3.11, 95 % CI 1.61-6.01, p = 0.001). Households located in Kaduna were more likely to have a higher number of seropositive SR compared to those in Plateau (Prevalence Ratio (PR)= 1.75, 95 % CI 1.30-2.36, p < 0.001), and households keeping sheep flocks were more likely to be seropositive (from 1 to 10 sheep: PR=1.39, 95 % CI 1.05-1.82, p = 0.02; more than 10 sheep: PR=1.55, 95 % CI 1.12-2.15, p = 0.008) compared to those that did not keep sheep. A hot-spot was detected in Kaduna, and a cold-spot in Plateau. These results reveal that small ruminants had been recently exposed to FMD virus with spatial heterogeneity across the study area.

Seroprevalence and associated risk factors for foot and mouth disease virus seropositivity in cattle in selected districts of Gamo zone, Southern Ethiopia

Background

Foot and mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals, which hampers livestock production and productivity in Ethiopia. This cross-sectional study was conducted from January to December 2021 to estimate the seroprevalence of FMD in cattle and to assess farmers' knowledge about the disease in selected districts of the Gamo zone. Three districts and two kebeles (smallest administrative division) from each district were purposively sampled using a simple random sampling technique to select individual animals from each kebeles. A total of 384 sera samples were collected, and concurrently, 100 farmers were interviewed. The samples were tested for antibodies against nonstructural proteins of the FMD virus using a 3ABC enzyme-linked immunosorbent assay (ELISA). Univariable and multivariable logistic regressions were used to analyze FMD-associated risk factors.

Result

The questionnaire survey result revealed that among the interviewed farmers, 66% of farmers had knowledge about the disease, and 28% of farmers reported having a case of FMD in at least one cattle in their farm in the previous 6 months. The overall seroprevalence of FMD in cattle was 26.8%. The multivariable logistic regression revealed that age, breed, and agroecology had a significant association with seropositivity. Higher seroprevalence (64.57%) was observed in lowland, followed by midland (9.30%) and highland (5.88%). Study animals from lowland areas were 9.26 times more likely to be seropositive (OR = 9.26, CI = 2.22–38.62) for FMD than highland animals. Also, adult animals were 9.01 times (OR = 9.01, CI = 3.18–25.53) more likely to be seropositive for the disease than young animals. The multivariable logistic regression revealed that crossbreeds have an 84.7% (OR = 0.153, CI = 0.028–0.82) lower likelihood to be seropositive to FMD than local breeds.

Conclusion

This study result confirms that FMD is highly prevalent in the study area, and farmers' knowledge regarding disease transmission and vaccine availability is minimal. Hence the regional concerned bodies should implement FMD vaccination campaigns and create awareness for smallholder farmers regarding the disease transmission, FMD vaccine schedule, and vaccination importance.

Crossing the Line: Seroprevalence and Risk Factors for Transboundary Animal Diseases Along the Tanzania-Zambia Border

Transboundary pathogens pose a threat to livelihood security in countries such as Zambia and Tanzania. This study aimed to investigate the seroprevalence of peste des petits ruminants virus (PPRV), foot and mouth disease virus (FMDV), sheep and goat pox virus (SGPV), Rift Valley fever virus (RVFV) and Brucella spp. in sheep and goats along the Tanzania-Zambia border. Another aim was to assess the association between certain predictor variables and seroprevalence, focusing on trade and proximity to an international border, to a town and to the Tanzania-Zambia highway. During September-October 2018, 486 serum samples from small ruminants in Zambia and 491 in Tanzania were collected and analyzed using enzyme-linked immunosorbent assays (ELISA). A questionnaire focused on management strategies was administered to each household. The animal-level seroprevalence in Zambia was 0.21% [95% confidence interval (CI) (0.01–1.14) for PPRV, 1.03% (95% CI 0.33–2.39) for FMDV, 0% (95% CI 0–0.76) for SGPV, 2.26% (95% CI 1.14–4.01) for RVFV and 1.65% (95% CI 0.71–3.22) for Brucella spp.]. In Tanzania, animal-level seroprevalence was 2.85% (95% CI 1.57–4.74) for PPRV, 16.9% (95% CI 13.7–20.5) for FMDV, 0.20% (95% CI 0.01–1.13) for SGPV, 3.26% (95% CI 1.87–5.24) for RVFV and 20.0% (95% CI 14.5–26.5) for Brucella spp. For PPRV (OR 6.83, 95% CI 1.37–34.0, p = 0.019) and FMDV (OR 5.68, 95% CI 1.58–20.3, p = 0.008), herds situated more than 30 km from an international border were more likely to be seropositive, while being located 10–30 km (OR 4.43, 95% CI 1.22–16.1 p = 0.024) from a border was identified as a risk factor for Brucella spp. For FMDV (OR 79.2, 95% CI 4.52–1388.9, p = 0.003), being situated within 30 km from a town was associated with seropositivity. Furthermore, contact with wild ruminants (OR 18.2, 95% CI 1.36–244), and the presence of sheep in the household (OR 5.20, 95% CI 1.00–26.9, p = 0.049), was associated with seropositivity for PPRV, and FMDV. No significant associations between trade or distance to the Tan-Zam highway and seroprevalence were found. We recommend that the impact of trade and proximity to borders, towns and roads should be further evaluated in larger studies, ideally incorporating aspects such as temporal trade fluctuations.

Epidemiological study on foot-and-mouth disease in small ruminants: Sero-prevalence and risk factor assessment in Kenya

Foot-and-mouth disease (FMD) is endemic in Kenya affecting cloven-hoofed ruminants. The epidemiology of the disease in small ruminants (SR) in Kenya is not documented. We carried out a cross-sectional study, the first in Kenya, to estimate the sero-prevalence of FMD in SR and the associated risk factors nationally. Selection of animals to be sampled used a multistage cluster sampling approach. Serum samples totaling 7564 were screened for FMD antibodies of non-structural-proteins using ID Screen^® NSP Competition ELISA kit. To identify the risk factors, generalized linear mixed effects (GLMM) logistic regression analysis with county and villages as random effect variables was used. The country animal level sero-prevalence was 22.5% (95% CI: 22.3%-24.3%) while herd level sero-prevalence was 77.6% (95% CI: 73.9%-80.9%). The risk factor that was significantly positively associated with FMD sero-positivity in SR was multipurpose production type (OR = 1.307; p = 0.042). The risk factors that were significantly negatively associated with FMD sero-positivity were male sex (OR = 0.796; p = 0.007), young age (OR = 0.470; p = 0.010), and sedentary production zone (OR = 0.324; p<0.001). There were no statistically significant intra class correlations among the random effect variables but interactions between age and sex variables among the studied animals were statistically significant (p = 0.019). This study showed that there may be widespread undetected virus circulation in SR indicated by the near ubiquitous spatial distribution of significant FMD sero-positivity in the country. Strengthening of risk-based FMD surveillance in small ruminants is recommended. Adjustment of husbandry practices to control FMD in SR and in-contact species is suggested. Cross-transmission of FMD and more risk factors need to be researched.

Seroprevalence and Molecular Detection of Foot and Mouth Disease Virus in Dairy Cattle Around Addis Ababa, Central Ethiopia

BACKGROUND

Foot and mouth disease is a debilitating and highly contagious transboundary disease of cattle that can cause a huge economical loss globally. It is a notifiable disease in Ethiopia, and it is thought to be causing a decrease in cattle productivity and production.

METHODS

A cross-sectional study and outbreak investigation were performed to estimate seroprevalence, identify associated factors and serotypes of FMDV in dairy cattle around Addis Ababa. A multi-stage random sampling technique was employed for the selection of sampling units for the seroprevalence study. A total of 383 blood samples were collected using plain vacutainer tubes and the obtained sera were tested by 3ABC-Ab ELISA at the NAHDIC lab. Also, from outbreak cases, 20 epithelial tissue samples were collected purposively for the molecular detection of FMDV serotypes.

RESULTS

The overall seroprevalence of FMD in dairy cattle was 72.1% (95% CI=67.27-76.50). The seroprevalence in dairy cattle of Ada Berga, Holeta, and Sululta districts was 97.2%, 71.4%, and 57.6%, respectively. Up on Chi-square analysis, age, body condition, and management system were significantly associated with FMD seroprevalence (p<0.05). Besides, multivariable logistic regression analysis showed that district, age, body condition, and management were significantly associated with FMD seroprevalence (p<0.05). The odds of being seropositive to FMD were 6.9 (95% CI=1.8-24.9; p=0.005) and 2.3 (95% CI=1.2-4.7; p=0.01) times higher in cattle found in Ada Berga and Holeta Woreda. From outbreak cases, 18 (90.0%) were identified positive for FMDV serotype O.

CONCLUSION

The current study revealed higher seroprevalence was recorded in the study area and associated risk factors identified statically, serotype O of FMDV was identified from outbreak cases. Therefore, it is critical to design and implement feasible control and prevention mechanisms based on the type of circulating virus serotype.