Open Veterinary Journal, (2025), Vol. 15(3): 1488-1494

Research Article

10.5455/OVJ.2025.v15.i3.38

Prevalence and risk factors of rabies in Côte d’Ivoire from 2020 to 2023

Yacouba Kouassi Mamadou¹, Kallo Vessaly², Zobo Anicet Aristide³, Sevidzem Silas Lendzele^4*, Douyeri Thierry Ouattara² and Acapovi-Yao Geneviève Lydie¹

¹UFR Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire

²Direction des Services Vétérinaires (DSV), Abidjan, Côte d’Ivoire

³National Laboratory for Agricultural Development (LANADA), Bingerville, Côte d’Ivoire

⁴Département de santé environnement, Laboratoire d’écologie des maladies transmissibles (LEMAT), Faculté des Technologies et management de la santé, Université Libreville Nord, Libreville, Gabon

*Corresponding Author: Sevidzem Silas Lendzele. Département de santé environnement, Laboratoire d’écologie des maladies transmissibles (LEMAT), Faculté des Technologies et management de la santé, Université Libreville Nord, Libreville, Gabon. Email: sevidzem.lendze [at] gmail.com

Submitted: 07/11/2024 Accepted: 17/02/2025 Published: 31/03/2025

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Abstract

Background: Zoonotic diseases remain a major public health problem. In Côte d’Ivoire, rabies causes significant economic losses in human and animal populations.

Aim: To determine the prevalence and risk factors of animal rabies in Côte d’Ivoire.

Methods: A retro-prospective study was conducted in which surveillance registers of the Directorate of Veterinary Services were consulted and information from 2020 to 2023 on rabies in different animal species was recorded and analyzed.

Results: A total of 152 people were exposed to animal rabies. Of the 147 brain tissue samples obtained from various animal species suspected of rabies and sent to the Central Veterinary Laboratory of Bingerville (LANADA), viral examination of these samples using the direct immunofluorescence technique method showed that 111 samples were positive for rabies, representing an overall prevalence of 75.51% (95% CI: 67.74%–82.22%). The most affected animal species were dogs, with a prevalence of 74.83% (110/147) and a very low prevalence in cats [0.68% (1/147)]. The association between cases of rabies and risk factors showed that males [79.81% (83/104)] were more exposed to rabies than females [65.12% (28/43)]. Animals aged ≥ 36 months [79.75% (63/79)] had a higher risk of infection than their younger counterparts [70.59% (48/69)]. However, vaccinated animals had a lower risk of contracting rabies. Stray animals that had been in contact with rabies-infected counterparts had a higher risk of infection [˃90% (81/89)].

Conclusion: It is clear that this zoonosis remains a permanent public health threat to the population of Côte d’Ivoire, and it is important to implement a national epidemiological surveillance network to better manage this disease.

Keywords: Surveillance, Rabies, Risk factors, Côte d’Ivoire.

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Introduction

Rabies is a zoonotic disease that derives its etymological meaning from the Latin word “rabere” which means mad (Tarantola, 2017). It is a severe viral disease that can spread rapidly in animal and human populations (Hampson et al., 2015). Dogs are the main carriers of this disease in humans (Bourhy et al., 2004). This disease originates from warm-blooded mammals, particularly carnivores, which act as reservoirs and vectors of the rabies virus (Bourhy and Reynes, 2013). The zoonosis is generally transmitted in an invasive manner through saliva that penetrates the skin following a bite. This condition leads to encephalitis with distinct symptoms that result in death (Tarantola, 2017). The World Health Organization (WHO) actively monitors this disease. Indeed, even though it has declined significantly in Europe due to the oral vaccination of foxes (Brochier, 1998), its seriousness in the rest of the world should not be underscored. It affects nearly 59,000 individuals globally each year, and 95% of them come from Asia and Africa (OIE, 2022). Africa pays a heavy price for this disease, with 24,000 fatal cases annually, according to recent WHO estimates (Knobel et al., 2005).

The WHO, the World Organization for Animal Health, and the Food and Agriculture Organization of the United Nations consider this disease a priority through a so-called “Tripartite” alliance to eradicate it (OIE, 2016). The elimination of this disease will not only save 300,000 lives in 5 years, but will also improve the living conditions of thousands of people. In Africa, the estimated annual cost of rabies is 583.5 million US dollars, with the cost of post exposure treatment of patients accounting for most of the expenditure. In Côte d’Ivoire, a country located in West Africa, rabies is a public health problem despite the existence of effective human and veterinary vaccines. This country has approximately 66% of rabies deaths in rural areas, with early 50% of survivors occurring among children. The annual cost of rabies is estimated to be around 20 billion Franc de la Coopération Financiѐre en Afrique (Kallo et al., 2019). Epidemiological data showed a significant prevalence in some cities of the country, such as Abidjan, with a prevalence of 2.5% among stray dogs (Coulibaly et al., 2024). In 2017, all institutions involved in the promotion of “One Health” research made rabies a priority. To this end, a National Integrated Rabies Control Program was developed and adopted. The implementation of this program has made it possible to achieve the global objective of zero cases of human rabies by 2030 (FAO and MIRAH, 2020). The aim of this study was to determine the prevalence of animal rabies from 2020 to 2023 and the related risk factors.

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Materials and Methods

Study area

Brain tissue sampling was carried out in 17 departments, including the north (Minignan, Odienné, and Boundiali), Center (Béoumi and Bouaké), West (Biankouma, Soubré, Gabiadji and Man), East (Transua and Youndouo), and South (Tabou, Guitry, Alépé, Adzopé, Jacqueville and Abidjan) (Fig. 1). The collected samples were analyzed at the Central Veterinary Laboratory of Bingerville (LANADA). These communes or departments were chosen on the basis of cases of animal rabies notified by the veterinary services.

Data collection

This study was based on the analysis of data from the Veterinary Services Directorate on animal rabies reports recorded and managed at the national level from January 2020 to June 2023.

The identification of animals involved and the type of exposure to rabies were carried out from animal consultation registers, animal vaccination registers, and annual reports. The data harnessed had the following sampling information: year, month, localities, animals involved, people exposed, and type of exposure. After data collection, the frequency of cases was calculated using the following formula:

Brain tissue samples from animals in the various departmental and municipal branches suspected of rabies were sent by post or by bus to LANADA for analysis using the direct immunofluorescence (DIF) technique. This technique consists of marking the antibody with a fluorochrome and reactivity with the specific antigen. The product is then observed under a fluorescence microscope. A sample was confirmed positive when an Antibody-Antigen complex was formed, which was marked by fluorescence on the microscope screen (Fig. 2). After the various analyses at LANADA, the prevalence was calculated using the following formula:

The main risk factors for animal rabies were determined on the basis of the association between rabies, age (0 to 36 months and 36 months and over), sex (male and female), behavior (calm or aggressive), and vaccination status (vaccinated or not) of the animals as well as the occurrence of stray animals or not.

Data analysis

The generalized linear model (GLM) was used to compare the prevalence and frequency of exposure to rabies in different localities. The Tukey post-hoc test was used to compare and classify the exposure areas based on their prevalence and relative frequencies. Correspondence factor analysis was used to characterize the distribution of this disease according to locality. In addition, a GLM is used to compare the effects of different risk parameters. All statistical tests were performed using Statistica 7.1 and Past 1.1 software. For each relative frequency and prevalence, a confidence interval was defined at the 5% threshold.

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Results

Occurrence and distribution of rabies from 2020 to 2023

During the study period from 2020 to 2023, 152 people were exposed to animal rabies. The number of bitten subjects was 96 (63.16%) in 2023, 28 (18.42%) in 2022, and 8 (5.26%) and 20 (13.16%) in 2021 and 2020, respectively (Table 1).

The distribution of bitten subjects by locality and year made it possible to distinguish three major groups. The first set on the left was negatively correlated to axis 1 (49.78% contribution) and positively correlated to axis 2 (35.68% contribution), and it regrouped localities such as Soubré, Youndou, Béoumi, Yopougon, Tabou, Adzopé, Odienné, Man, Alépé, Guitry, Jacqueville, Transua, and Biankouma, where bitten subjects were recorded in 2023. The second set correlated negatively by axes 1 and 2 and consisted of Abobo, Cocody, Boundiali, Katiola, Bingerville, and Bouaké, where the bitten subjects were recorded in 2020 and 2021. Finally, the third set located above group 2 regrouped Minignan and Gabiadji, where the bitten subjects were recorded in 2022 (Fig. 3). The GLM showed that the distribution of bitten subjects by locality and sampling years statistically differed significantly (ddl=20; W=147.37; p < 0.00001).

Fig. 1. Map of the ivory coast showing the study sites in Côte d’Ivoire between 2020 and 2023.

Of the 147 brain tissue samples collected from various animal species suspected of rabies and sent to LANADA from 2020 to June 2023, viral examination of these samples using the DIF method showed that 111 samples were positive for rabies, i.e., an overall prevalence of 75.51% (95% CI: 67.74%–82.22%) (Table 2). The most affected animal species were dogs (74.83% (110/147), but this was very low in cats [0.68% (1/147)].

Risk factors associated with animal rabies infections in biting dogs at veterinary clinics

The associations between the occurrence of rabies and risk factors are mentioned (Table 3). Males [79.81% (83/104)] were more exposed to rabies than females [65.12% (28/43)]. Animals aged ≥36 months [79.75% (63/79)] had a higher risk of infection than younger animals [70.59% (48/69)]. Animals with aggressive behavior [76.22% (109/143)] had a higher risk of rabies infection than animals with calm behavior [50% (2/4)]. However, vaccinated animals had a lower risk of contracting rabies. Stray animals that had been in contact with infected animals had a high risk of infection [˃90% (81/89)].

Fig. 2. Presence of a positive dog case of rabies on a slide viewed under the microscope (formation of an antigenantibody complex).

Table 1. Distribution of the number of people who visited health facilities for animal bites in Côte d’Ivoire in 2020 and 2023.

Fig. 3. Distribution of bitten subjects by locality and year in Côte d’Ivoire.

Table 2. Results of diagnosis of rabies in biting animals in Côte d’Ivoire between 2020 and 2023.

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Discussion

Rabies is a zoonotic disease that remains a permanent threat to both animal and human populations and is a concern for veterinary services. This study identified the animals involved (dogs, and cats) and associated risk factors. This study showed that dogs were frequently infected with this disease. These results are similar to those of Benyahia and Bouahadjar (2020), who conducted a study in Algeria and reported dogs as the most infected animal species. However, a study conducted by Servat et al. (2020) in France showed that bats are the most affected by rabies. This difference could be explained by the fact that bats can travel long distances and easily transmit the virus. This study also highlighted the high prevalence of this disease in several localities in the country and enabled an understanding of the evolutionary dynamics of this disease. These high prevalences in all the studied localities could be due to the presence of vegetation that constituted reservoirs for wild animals and hence a source of infection for the domestic animal species studied. The results obtained agree with those of Hind (2022), who found that dog owners in rural areas neglected the health of their animals and their living conditions, leading to their increase in such settings.

The present study also focused on the risk factors associated with animal rabies. Male animals were more infected than their female counterparts. This assertion is consistent with Mediouni (2019), who conducted an epidemiological study in Montreal and reported that male dogs were highly infected. A similar observation of higher numbers of male-infected cases in Algeria was made by Haleche (2020). Consequently, they tend to bite other dogs and other animal species that are grazing around them. Regarding age, older animals contracted this disease than younger animals (Haleche, 2020). This could probably be explained by the fact that during puberty, female dogs accept males, leading to intimate contact, and the phenomenon of the dental group at this age results in their aggressive nature. On the other hand, studies conducted by Sylla (2021) in Bamako have found that school-aged children are the most affected by this disease. During these studies, the author noted that children were much closer to dogs and that the latter could easily be bitten by them.

This study revealed that unvaccinated animals were most commonly exposed to rabies. This finding is similar to that of Thomas et al., (2013), who reported that 35% of animal owners had never visited a rabies center. This study showed that stray dogs were the most affected by this disease. This could be because these animals do not receive more attention when it comes to feeding and health, and most of them have a history of vaccination. It was observed that most dogs go around in search of food and become aggressive when disturbed by humans and other animal species, which could be a possible mechanism for the spread of rabies. These observation results corroborate those of Benyahia and Bouahadjar (2020) where it was reported that dogs were outside the home.

Table 3. Risk factors associated with animal rabies in Côte d’Ivoire between 2020 and 2023.

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Conclusion

The results revealed that animal rabies still exists and is present on the national territory, with 63.16% of bite cases. This zoonosis is especially prevalent in rural areas in several localities of the country, particularly in the Guitry region, where it occurs in 39% of cases. In the Ivory Coast, rabies is a serious public health problem. Dogs are the main reservoir, accounting for more than 56.58% of bite cases. Male animals (dogs) had a high risk of infection, with more than (79.81%) cases against (65.12%) for females. Despite the efforts of the departments involved in the fight against rabies, the risk persists. Therefore, rabies remains a current issue with all the problems caused by this pathology.

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Acknowledgments

The authors thank the authorities of the Direction of Veterinary Services for accepting us to share the data on rabies in animals.

Conflicts of interest

The authors declare that they have no conflicts of interest.

Funding

The authors did not receive any funding for this study.

Authors’ contributions

AYGL and YKM conceived and designed the study. Field sampling, data collection, and laboratory work: YKM. Data entry, analysis, and interpretation: YKM, AYGL, SSL, KV, DTO, and ZAA. The manuscript was drafted by YKM, SSL, and AYGL, and ZAA, DTO, SSL, and AYGL revised the intellectual content. All authors have read, reviewed, and approved the final version of the manuscript.

Data availability

All data used to support the primary findings of this study are included in the manuscript. Complete datasets generated and analyzed during the study are available from the corresponding author upon reasonable request.

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