Prevalence of camel trypanosomosis and herders’ knowledge, attitude, and practices towards the disease in the pastoral area of southern Ethiopia

Abstract

Background

Surra is a parasitic disease caused by Trypanosoma evansi that threatens the health and productivity of camels. Despite its significant impact on camels in Ethiopia, surra has not received as much attention as diseases in cattle and other domestic animals. The objective of the study was to estimate the prevalence of surra, identify the potential risk factors and assess the traditional knowledge, attitude and practices of camel herders towards the disease.

Methods

The study used a parasitological and participatory epidemiological (PE) approach. Between February and July 2022, a total of 335 blood samples were collected from camels across three districts and tested using the buffy coat technique. The PE investigation involved six key informant groups consisting of 8 to 12 key persons, and used a semi-structured interview and various PE tools and principles.

Result

The study found that the prevalence of surra among examined camels was 3.9% (95% CI: 2.1–6.5). The prevalence was significantly higher in camels with a poor body condition score (BCS) (OR = 9.3; 95% CI: 1.8–47.5; p = 0.008) compared with camels with a good BCS. However, district, age, sex, and ethnicity had no effect on the prevalence of surra (p > 0.05). The study also found that the packed cell volume (PCV) was significantly lower (p < 0.0001) in parasitaemic animals (18.92 ± 2.63) than in aparasitaemic animals (25.13 ± 4.56). Camels with poor BCS (22.7 ± 3.5) had a significantly (p < 0.001) lower mean PCV than camels with good BCS (26.2 ± 5.0). The PE investigation showed that all the camel herders were well aware of surra, known locally as Dhukana. The clinical symptoms, the season of high incidence, routes of transmission, impact on production, and control methods were accurately described. Moreover, this study emphasized that surra is the primary disease affecting camel health and productivity.

Conclusion

The study identified a moderate prevalence of surra in the research area. To reduce surra incidence and associated losses, enhancing veterinary services and providing support for proper camel husbandry practices in the region is recommended. Additionally, future studies should consider using more sensitive and specific techniques like serological and molecular assays, as this study relied on microscopy only.

Introduction

Camels are crucial for the livelihood of many pastoral and agro-pastoral communities in arid and semi-arid regions of Africa and Asia [1]. In Ethiopia alone, there are over 7 million camels [2], playing a vital role in the livelihood of pastoralist communities, especially in arid and semi-arid areas such as Afar, Ethiopian Somali, and parts of Oromia including the Borena zone. They provide milk, meat, transport, and other benefits to their owners, and their population is significant in these areas [3]. Camels produce more milk and lactate for longer than any other milking animals raised under similarly harsh environmental conditions [4].

Although Ethiopia is a home to one of the largest camel populations in the world, there are several challenges that hinder the full exploitation of this resource including climate change, disease and parasites, limited access to veterinary services, limited access to markets and limited research and development [5]. Although trypanosomosis was not well studied in camels as other domestic animals, it is the major health problem in camels reported in Ethiopia [6].

Camel trypanosomosis, also known as Surra, is the most important and serious pathogenic protozoan disease of the camel. It is caused by Trypanosoma evansi and transmitted mechanically by haematophagous biting flies, especially tabanids and Stomoxys spp [7]. It has a wide range of distribution in tropical and subtropical regions of the world [8]. Surra is characterized by fever, progressive emaciation, anaemia, subcutaneous oedema, loss of appetite, loss of condition and productivity, nervous signs, abortion and death and is considered the most important health problem in camels [9]. It is most severe in horses, donkeys, mules, camels, dogs and cats. Like other pathogenic trypanosomes, T. evansi induces generalized immunosuppression [8, 10].

In Ethiopia, surra has a significant impact on the health and production of camels, but it has not received as much attention as diseases in cattle and other domestic animals. This lack of attention to surra is concerning given its impact on camel health and production. There are only limited studies available on this disease. According to the available studies, the prevalence ranges from 2.63 to 10.5% based on buffy coat examination technique [ 11, 12, 13, 14, 15 16, 17,18]. These studies are insufficient to develop efficient control and preventive measures against the disease, given the large number of camels in the nation.

The Borena herders in southern Ethiopia have long relied on cattle for milk and wealth, but they are now increasingly interested in camel production [5, 19]. This shift is influenced by various factors, including environmental changes, social conditions, and seasonal migrations, which have spurred camel production on the Borena Plateau. It’s worth noting that the traditional knowledge that has been accumulated over the years was not acknowledged, and the local competence of pastoral people was not assessed or compared with the modern scientific approach in the study area.

The current study aims to bridge this gap by estimating the prevalence of surra, identifying potential risk factors, and assessing the indigenous pastoralists’ knowledge, attitudes and practices towards surra in the Borena pastoral zone of Ethiopia.

Materials and methods

Study area

The study took place in the Yabello, Elwaye, and Gomole districts of the Borena Zone in the Oromia Regional State of Ethiopia (Fig. 1). Yabello district is situated at 4°53′N 38°5′E, with an elevation ranging from 350 to 1857 meters above sea level. Elwaye district is found at an altitude of 1327 meters above sea level, at 4.884°N 38.082°E, while Gomole district is situated at an altitude of 1857 meters above sea level, at 4° 45’ 0” North latitude and 38° 22’ 0” East longitude. The area is characterized by extensive pastoralism and seasonal livestock mobility, predominantly focused on cattle. However, due to increasing aridity, livestock is shifting from cattle to camels, which are socially important. Borana zone receives annual rainfall between 350 mm and 900 mm [20], with mean maximum and minimum temperatures of 24.6 °C and 12.96 °C, respectively [21].

Fig. 1

Map the study area

Study animals

The study population was dromedary camels including of all sex, different age groups and body condition found in Yabello, Gomole and Elwaye districts and managed under pastoral production systems. Borana households maintain camel herds of varying sizes, ranging from a few heads (around five to ten) to several hundred. The herd consists of over 75% female camels. Male camels are typically sold early, either as pack animals or for slaughter. Female camels remain fertile for an impressive 25 years, during which they can produce eight to ten calves. Breeding is seasonal and influenced by rainfall patterns and feed availability. Camels are herded during the daytime on communal range lands and kept in traditional kraals near homesteads at night. Milking is primarily done by men, with a frequency ranging from two to five times per day. The age of the animals was determined based on information from the owners. Camels aged 4 years or below were considered as young, while those above 4 years of age were categorized as adult [17]. The body condition score (BCS) of camels was assessed according to appearance of ribs and dorsal spines [22] and the result was recorded as poor, medium, and good.

Study design and sampling methods

A cross-sectional study was conducted from February 2022 to July 2022, which consisted of two surveys - a parasitological survey and a participatory epidemiological (PE) survey. The purpose of the parasitological survey was to estimate the prevalence of camel trypanosomosis and identify the potential risk factors in three selected districts. On the other hand, the PE survey aimed to assess the perceptions of pastoralists regarding camel trypanosomosis and traditional practices implemented to prevent and control the disease. The three districts were selected purposively based on the camel population and accessibility. Six pastoral kebeles were selected from the three districts, with two kebeles selected from each district. A kebele is the smallest administrative unit in Ethiopia. A total of 24 villages were selected from these kebeles by using simple random sampling. Villages are characterized by the clustering of households with proximity houses in a pastoral camp. Each village is traditionally administered by a village chief, who is an important contact person in facilitating cooperation among camel owners. Sampling frames of camel herds were obtained from a village chief in each respective village. Simple random sampling techniques were employed to select camel herds from each village and individual camels from each herd.

Sample size determination

The sample size required for estimating the prevalence of camel trypanosomosis was calculated following Thrusfield [23], taking into account a 95% confidence level, an anticipated prevalence of 3.5% derived from previous studies’ average [17, 24], and a 2% absolute precision, using the following formula:

$$\:\text{n}=\frac{{\text{Z}}^{2}{\text{P}}_{\text{e}\text{x}\text{p}}\left(1-{\text{P}}_{\text{e}\text{x}\text{p}}\right)}{{\text{d}}^{2}}$$

(1)

Where n = required sample size, Z = 1.96, d = desired absolute precision, and Pexp = expected prevalence (3.5%). Consequently, the required sample size was determined to be 335.

Study methods

Parasitological examination

The buffy coat method was utilized to detect T. evansi in blood samples from 335 study animals. as described in [25]. After physically restraining the animal by the owner, blood samples were collected from each animal by ear vein puncture using a sterile lancet into a pair of heparinized microhematocrit centrifuge capillary tubes (75 × 1.2 mm). Each tube was filled to approximately two-thirds of its length and then sealed at one end with a crystal seal (Hawaksly, England). The tubes were placed symmetrically on a microhematocrit centrifuge and spun at 12,000 rpm for 5 min. After centrifugation, packed cell volume (PCV) was measured using a haematocrit reader (Hawaksly, England), ) to determine the level of anemia. The values were expressed in percentages. Animals with PCV < 24% were considered to be anemic [26]. The capillary tubes were then cut using a diamond-tipped pen 1 mm below the buffy coat to include the top layers of red blood cells and 3 mm above to include the plasma. The contents were expressed onto a clean slide, mixed well and covered with a 22 × 22 mm coverslip. Then the wet smear was examined with X40 objective lens for the presence of motile trypanosomes. Confirmation of trypanosome species was made by examining Giemsa-stained thin smears at X100 magnification [27].

Participatory epidemiological (PE) investigation

A participatory epidemiological (PE) investigation was conducted with six informant groups, each consisting of 8 to 12 key individuals. These groups included both male and female herd owners with extensive experience in herding and rich indigenous knowledge of camel husbandry and health care. Data collection methods for the PE study included semi-structured interviews, simple ranking, pair-wise ranking, matrix scoring, proportional piling, and seasonal calendars [28]. All the questions and checklists used for the PE investigation are available as supplementary file (SF1).

Semi-structured interviews

The study conducted semi-structured interviews using a checklist that was developed specifically to gather information on the major constraints of camel production, major camel diseases observed over the past year, and camel health care and disease prevention [28, 29].

Simple ranking

The key informant groups were asked to list and rank major constraints for camel production and the major camel diseases in their district based on their importance. They ranked the given criteria one after another [28, 29].

Pair-wise ranking

Key informant groups ranked the ten most common camel diseases by severity through a pair-wise ranking process. Each disease was compared to every other disease individually. Disease names were written on cards, and participants compared two diseases at a time in terms of importance. Probing questions were asked to understand the reasons behind their choices and how they differentiated between the diseases. Based on the scores in the pair-wise comparisons, the diseases were then ranked from first to tenth, with the highest scoring disease ranked first and the lowest scoring one ranked last [28, 29].

Matrix scoring

Key informant groups compared the five most commonly ranked camel diseases using a matrix scoring system. The goal was to identify disease indicators, particularly the clinical signs, using 30 counters. Surra was the primary focus, while the other diseases were considered control diseases [28, 29].

Proportional pilling

Proportional piling was utilized to assess the morbidity, mortality, and case fatality rates of camel trypanosomosis within the year prior to the study. Participants were given a pile of 100 counters to represent the number of animals in their camel herds. They then split the pile into two, representing the proportions of sick and healthy animals. The pile representing sick animals was further divided to show the proportions of camels affected by surra, as well as a group labeled as “other diseases.” Subsequently, participants divided the pile representing each surra to indicate the proportions of animals that recovered and those that died from the disease during the year. Through discussion and consensus, pastoralists provided reasons for their choices and agreed upon the scores for each disease. This activity was repeated across all six group discussions [28, 29].

Seasonal calendar

Seasonal calendars were used to show the occurrence of the top five camel diseases throughout the year. We conducted semi-structured interviews to understand the different seasons using the local language in the study area. Objects representing local seasons were placed on the x-axis, while diseases written on cards were placed on the y-axis. To score the relationship between seasons and camel diseases, we used 30 bean seeds as counters. After placing the counters for a specific disease against the corresponding season, participants were allowed to thoroughly review the scores. If desired, they could rearrange the scores until they were satisfied with the results, which were then recorded as the agreed-upon outcomes. This process was repeated for each disease, resulting in the progressive expansion of the matrix [28, 29].

Statistical analysis

The data that was gathered during the study was entered into a Microsoft Excel spreadsheet, after which it was filtered and coded before undergoing statistical analysis. The parasitological data was analyzed using Stata version 14.2 (College Station, TX: StataCorp LP), while the PE data was analyzed using SPSS software. The association of surra with various potential risk factors was analysed using logistic regression analysis. The degree of association was computed using odds ratio (OR) and 95% confidence interval (CI). The age, sex and body condition score (BCS) of camels, district, and ethnicity were the independent variables considered as potential risk factors during the analysis. The difference in mean PCV% between parasitaemic and aparasitaemic animals was evaluated using two-sample t-test, while the difference in mean PCV% among camels with different BCS was evaluated using one way analysis of variance (ANOVA). Descriptive statistics were computed for all the parameters. A p-value of < 0.05 was considered as indicative of a statistically significant difference.

Data from participatory epidemiological investigations were presented descriptively as tables based on mean rank values. The levels of agreement between informant groups on the data obtained from simple ranking, pairwise scoring and matrix scoring was assessed using Kendall’s coefficient of concordance (W). Evidence of agreement between informant groups was categorized as ‘weak’ (W < 0.26, p > 0.05), ‘moderate’ (W = 0.26–0.38, p < 0.05) and ‘strong’ (W > 0.38, p < 0.01) as previously described in [29].

Results

Parasitological examination

Prevalence of camel trypanosomosis

Out of 335 camels tested, 3.9% were found to be positive for trypanosomosis using the buffy coat technique. The prevalence of trypanosomosis was 6.2% in the Yabello district and 3.6% in the Gomole district. No trypanosome infection was detected in Elwaye district (Table 1). The study identified Trypanosoma evansi as the only species present. In the blood smears, it was identified by its slender body, centrally located nucleus, free flagellum, prominent undulating membrane, and sub terminal kinetoplast (Fig. 2).

Table 1 Prevalence of camel trypanosomosis in the Borena Zone based on study districts

Fig. 2

Image of Trypanosoma evansi from an infected camel captured during the study

Risk factors for trypanosomosis

District, age, sex, BCS, and ethnicity were all potential risk factors examined in the univariable logistic regression analysis. Among these variables, BCS was the only one that was associated with a higher prevalence of trypanosomosis in camels (p = 0.008). Camels with poor BCS were found to be 9.3 times more likely to get trypanosomosis than camels with good BCS. Although the prevalence of trypanosomosis was higher in camels from the Yabello than in Gomole district, in males than in females, in adults than in young camels, and in camels of the Borena ethnic group than in the Gabra group, no statistically significant differences were found (p > 0.05). Furthermore, all positive instances of trypanosomosis were found in herds of 15 or more camels, with no cases discovered in smaller herds. A multivariable logistic regression analysis was not undertaken because BCS was the only significant variable in the univariable analysis and all other variables had p-values larger than 0.2 (Table 2).

Table 2 Univariable logistic regression analysis of putative risk factors for camel trypanosomosis

Association of packed cell volume with trypanosome infection status and body condition score of camels

The PCV values of the camels studied ranged from 13 to 47%, with an average of 24.9 ± 4.7%. The average PCV for infected camels (18.9 ± 2.6%) was significantly (p < 0.0001) lower than that of uninfected camels (25.1 ± 4.6%) (Fig. 3). Additionally, there was a significant correlation between BCS and PCV (p < 0.001), as camels with poor BCS had a notably lower average PCV (22.7 ± 3.5%) compared to those with good BCS (26.2 ± 5%) (Fig. 4).

Fig. 3

The mean PCV (%) of camels based on their trypanosome infection status

Fig. 4

The mean PCV (%) of camels according to their body condition score

Participatory epidemiological study results

Major constraints for camel production in the Borena zone

Discussions with six key informant groups uncovered the main constraints impacting camel production. These include, in order of significance, diseases, feed and water scarcity, inadequate veterinary services, and a lack of attention to camels. There was a strong consensus (W = 0.52; p = 0.024) among the key informant (KI) groups regarding the prioritization of these limitations (Table 3).

Table 3 A simple ranking of important constraints on camel rearing in the Borena Zone

The majority of the KIs pointed out that while regular vaccination programs and treatment services were available for cattle, sheep, and goats, similar services were not provided for camels. According to them, the only annual vaccine given to camels is for camel pox. Another significant constraint in the region is the shortage of feed and the limited mobility of the herds. They mentioned that in the past, more than 152 trees were available for camel browsing, but due to local changes such as the use of important trees for charcoal production, overpopulation, land tenure issues, increasing crop agriculture, and the demarcation of administrative sub-units (pastoral kebeles), the availability of trees has declined by half. The KIs emphasized that these changes have led to a decline in the productivity of rangelands in terms of both extent and intensity.

The KIs unanimously agreed that herds from one administrative unit were not allowed to graze on the forage resource in another administrative unit. They emphasized that camels cannot be expected to have milk, meat, disease resistance, or a competitive market price without sufficient forage. The KIs also pointed out that both the pastoralists and the government have not paid much attention to improving the health care, management, and production aspects of camels. There is no longer communal grazing or browsing land available for camels, while there is ample land for cattle sheep, and goats. Furthermore, the KIs mentioned that the district agricultural offices often organize training for community animal health workers regarding the production and health care of other domestic animals, but there is no specific training on camel issues.

The most common camel diseases in the Borena zone

The study conducted semi-structured interviews with KIs to gather information about various diseases affecting camels. KIs listed several diseases affecting camels, with 10 selected for pair-wise ranking to prioritize them based on their impact on camel production and health. The overall priority disease was determined by calculating the frequency of responses from six group discussions. The diseases were identified by their local names, and the probable scientific name for each disease was provided. The diseases with the highest median scores were sequentially ranked from 1 to 10. The results showed that Dhukana (trypanosomosis) is the most significant disease, followed by Fino, Furi, Qanicha, Mala, Dhula, Simbirki, Dhuguda, Luk mur, and Sirgo. There was a good agreement (W = 0.395; p = 0.011) among the KI groups on the ranking of these diseases according to their impact on camel health and production (Table 4).

Table 4 Pairwise ranking of the most common camel diseases based on the severity of the infection

A comparison of the five most commonly ranked camel diseases was conducted by KI groups using a matrix scoring system. The aim was to identify disease indicators using 30 counters, with Dhukana (trypanosomosis) being the primary focus while the other four were control diseases. According to the KIs, the most significant signs of Dhukana were reduced milk production, emaciation, hair loss from the tail and nostrils, high mortality, and abortion and still birth (Table 5). The KIs also provided a clear explanation of the possible transmission methods for Dhukana. They indicated that biting flies transmit the disease, and that these flies are most abundant during the rainy seasons due to moisture-induced hatching. The informants even provided specific local names for some of the transmitting flies, such as Qodhabe during the rainy season, Ilawink during flowering time, Sorondisa during the dry season, and Ofe near mountain and bush areas. These flies are primarily found in bushy land, watering points, river banks, black clay areas, and near mountain basins, which are favourable habitats for fly hatching. They further stated that although all age groups are susceptible to trypanosome infection, but adult camels are particularly vulnerable to Dhukana as they are more exposed to biting flies when they browse in areas with abundant biting flies, such as the bush. The respondents also stated that camels contract the disease when they travel to another place for long distances and get mixed with other camels from neighbouring infected herds through biting flies.

Table 5 Summary of matrix scoring for the clinical signs of camel diseases in the Borena zone determined by the key informant groups

Seasonal calendar of top five camel diseases

The six KI groups were asked to divide a year into four seasons for matrix-scoring purposes. The identified seasons were Ganna (major rainy season), Adoolesa (cool dry season), Hagaya (short rainy season), and Bona Hagaya (dry season). Ganna was from March to May, Adoolesa from June to August, Hagaya from September to November, and Bona Hagaya from December to February. The informants were given 100 counters to indicate the seasonal occurrence of the five selected camel diseases, including trypanosomosis, in their locality. The seasonal calendar they constructed showed that the disease Dhukana (camel trypanosomosis) occurs in all seasons with the highest prevalence during the rainy season and the least in the dry season. The informants attributed the higher occurrence of Dhukana during the rainy (wet) season to the breeding and increase in the population of biting flies (Table 6).

Table 6 Summary seasonal calendar for the five most common camel diseases in the Borena zone

Proportional piling for camel morbidity and mortality

The results of proportional piling on disease prevalence and mortality showed that in the year before the study, 15.3% of camels had Dhukana (surra), 6% of camels died, and the case fatality rate was 26.7% (Table 7).

Table 7 Annual mean incidence, mortality, and case fatality rate of camel trypanosomosis as reported by the key informants

Camels’ healthcare management

According to the KIs, camel healthcare is mainly managed by herders and traditional healers, as veterinary services for camels are not easily accessible. The herders take care of their animals by getting medication from open markets and private veterinary drug shops. Unfortunately, there are no traditional medicines available for treating camel trypanosomosis, so herders must take preventative measures such as moving their camels away from fly-infested areas during fly hatching season and ensuring they have access to high-quality pasture. Nonetheless, some herders are now using modern drugs like isomethamedium chloride, ethidium, and triquin (a combination of Quinapyramine sulphate and chloride salts), which can be obtained illegally on the Kenyan corridor. While triquin is not legally recognized by the Ethiopian government for local use, the KIs mentioned that it is very effective in both curative and preventative measures. Many of the KIs agreed that modern methods of disease control and prevention are more efficient than traditional methods.

Discussion

The prevalence of trypanosomosis in the present study area was found to be 3.9%, closely matching the 3.91% reported by Rafu et al. [17] in the same study area. However, it is lower than previous estimates ranging from 4.4 to 10.65% across different regions of Ethiopia [11, 13, 14, 16, 18]. Conversely, it exceeds specific reports such as 2.63% in the Asayita district of Afar region [15] and 3.5% in the Jijiga zone of the Somali region [12]. This discrepancy may be attributed to agroecological differences and a higher density of T. evansi vectoring biting flies in the present study area. Furthermore, other countries have reported even higher prevalence using the same method, including 5.3% from Nigeria [30], 7% from Sudan [31], 11.25% from Pakistan [32] and 17.3% from Egypt [33]. The lower prevalence observed in our current study may be attributed to regular treatment of sick animals, the dry season during the study, and the avoidance of moving camel herds to areas where biting flies are prevalent. The participatory epidemiological survey revealed that the camel herders are well aware of the seasonality and ecology of the biting flies, which may have contributed to the lower prevalence of the disease in our study area. Additionally, Bogale et al. [34] highlighted the direct impact of season on the distribution of biting flies, which play a role in the mechanical transmission of T. evansi.

In the three districts surveyed, surra was found in Yabello and Gomole districts without a statistically significant difference. Rafu et al. [17] also reported a lack of variation in surra prevalence between the two mentioned districts, possibly due to similar camel management system and agroecology. The lack of trypanosome detection in Elwaye district may be due to the absence of vectors, though this requires confirmation in future vector studies. Additionally, the administration of trypanocidal drugs to camels could play a role. Many herds from the district received prophylactic drugs months prior to the study due to their proximity to the Segen River area in the Southern Ethiopian Region, where trypanocidal drugs are available. This could have impeded the detection of trypanosome infection through parasitological examination. In contrast, Abera et al. [35] and Olani et al. [24] reported a statistically significant difference in the prevalence of surra among the districts of Bale and Borena zones, respectively.

The study revealed a significant correlation between the BCS of camels and surra. Camels with a poor BCS were 9.3 times more likely to have surra compared to those with a good BCS. This result can be interpreted in two ways. Firstly, trypanosomosis may lead to progressive emaciation, explaining the higher prevalence in poorly conditioned camels. Secondly, animals with BCS may have weaker immunity, making them more susceptible to Trypanosoma infection than those with good BCS. This is supported by existing literature [10, 36] indicating that infected camels in good body condition possess a well-developed immune system better equipped to respond to foreign proteins compared to infected camels with poor body condition. These findings align with previous studies in the country and elsewhere [17, 18, 30, 33, 37, 38] which have also highlighted a strong association between camel trypanosomosis and poor body condition. This highlights the need to incorporate regular monitoring of camel body condition into current veterinary practices to facilitate early detection and proactive management of trypanosomosis outbreaks.

Literature suggests that an infected camel with PCV less than or equal to 24% is considered anemic [26]. In this study, the mean PCV of camels infected with trypanosomes was 18.9%, significantly lower than the 25.1% mean PCV in non-infected camels. This notable decrease in mean PCV indicates that surra causes anemia in infected camels and that anemia could serve as a reliable indicator of surra in endemic areas. This finding aligns with previous reports in Ethiopia and other countries [17, 18, 24, 31, 37, 39, 40] which also noted that the mean PCV of trypanosome-infected camels was significantly lower than non-infected camels.

Participatory epidemiology recognizes the knowledge of local communities about animals, infectious and zoonotic diseases. Farmers can describe clinical presentations, epidemiological patterns, and pathological lesions using local languages that correspond to Western clinical case definitions [28]. According to the PE approach, the major challenges faced by camel production in the Borena zone were identified as diseases, feed shortages, inadequate veterinary services, and a lack of attention to camels, in that order of significance. Key informant groups agreed strongly (W = 0.52; p = 0.024) on the prioritization of these limitations. Other researchers from Ethiopia [16, 41] and Somalia [42] have also found that diseases, poor veterinary services, and a lack of attention from the government were the most significant constraints to camel production. The KIs believe that the government has not given enough attention to improving the health care and production aspects of camels, despite their vital importance, especially for marginalized pastoral communities in the arid areas of the country. As a result, camels suffer from diseases and malnutrition, leading to a decrease in their numbers. Without proper health care and nutrition, camels are more susceptible to diseases and parasites, which can quickly spread through the herd. This can have a devastating effect on the pastoralists, as camels are their primary source of income, and they rely on them for food, medicine, and other essential items.

The study found that all herders (100%) were aware of camel trypanosomosis, a disease that they call ‘Dhukana’ in the local language They correctly defined the disease based on its typical signs and symptoms and ranked it as a priority due to its significant impact on the health and production of camels in the area. In addition, they were able to explain through proportional piling technique the percentage of camel morbidity, mortality and case fatality rate that resulted from surra in the year prior to the study. This underscores the ongoing importance of surra in the region and its continued significant impact on the livelihood of pastoral communities. Additionally, this finding emphasizes the necessity for the regional and federal governments to promptly allocate resources and implement control measures in order to reduce the losses inflicted by the disease on the pastoralists, who largely depend on camels for their livelihood. Consistent to the current findings, all (100%) respondents from pastoral communities in Kenya placed camel trypanosomosis (surra) among the top diseases affecting their camels [43], indicating its economic importance in pastoral areas. The herders in the present study also explained potential transmission factors for the disease, noting the role of biting flies as transmitters of trypanosomes, particularly during the rainy seasons. They also linked increased infection cases to a rise in the biting fly population. Consistent with this finding, most survey respondents in a Kenyan study associated the spread of the disease with the presence of biting flies, with a higher prevalence of such vectors reported during the wet season [43]. Furthermore, this finding aligns with the current scientific knowledge of the disease, emphasizing the crucial role of biting flies in transmitting camel trypanosomosis [8, 10, 16, 44].

The KIs created a seasonal calendar that showed the occurrence of the disease Dhukana (surra) in all seasons. It was found that the disease is most prevalent during the major rainy season (Ganna), followed by the cool dry season (Adoolesa) and the short rainy season (Hagaya), and least prevalent in the dry season (Bona Hagaya). The informants attributed the higher occurrence of Dhukana during the rainy season to the breeding and increase in the population of biting flies. Similarly, Giro and Jilo [16] reported a higher prevalence of the disease in the Arero district of the Borena zone during the major rainy season. The existing literature also supports the fact that surra prevalence in camels and other animals is higher during the rainy season when biting fly populations increase [8, 10, 36]. However, some studies have noted increased fly activity and surra cases during the dry or hot season in certain regions [43]. The current finding suggests that while prevalence is highest during the wet season, surra may be endemic in the Borena zone and could occur year-round due to persistent vector presence. Therefore, it is crucial to monitor fly density and surra prevalence throughout the year to implement appropriate preventive measures.

According to the KIs, camels can contract surra when they travel long distances and mix with camels from neighbouring herds that have been in contact with biting flies. Van den Bossche and Vale [45] also support this idea, stating that management factors and animal movement patterns can increase the risk of infection. The herders further explained that when camel herds congregate around water sources and pastures, it facilitates the transmission of the disease by biting flies.

The herders have confirmed that there is no traditional medicine available to cure surra. Therefore, they take preventive measures to avoid contracting the disease. One of these measures is to move their camels away from areas infested with biting flies, especially during fly hatching season. This indicates that the herders are fully aware that surra is transmitted by these flies and that avoiding contact with them reduces the risk of infection. This presents a valuable chance that can be utilized in future interventions aimed at controlling surra.

According to the KIs, camel health care is mainly carried out by herders and traditional healers due to the absence of veterinary services in their area. These herders have stated that they use modern drugs like isomethamedium chloride, ethidium and triquin, which they obtain from the black market in the Kenyan corridor, to treat sick camels by themselves. They believe that triquin, despite not being legally recognized by the Ethiopian government for local use, is a highly effective drug for both curative and preventative purposes. The herders’ understanding of triquin aligns with the existing literature, which indicated triquin, a combination of quinapyramine sulphate and quinapyramine chloride, is more effective and can be used as a curative or preventive drug against T. evansi in horses and camels [8]. However, the non-professionals administration of such medications could lead to drug resistance and complicate the treatment of surra. This highlights the need for immediate action to provide veterinary services and education to herders and traditional healers in these areas to ensure that camel healthcare is managed safely and effectively.

A significant limitation of the study was the reliance on microscopy for detecting trypanosomes, as financial constraints restricted access to more sensitive molecular and serological tests. Additionally, the absence of a survey on T. evansi vectors in the districts further limited the research.

Conclusion

Based on a participatory epidemiological study, surra is the most important disease affecting camel production and health in the Borena zone. However, the current prevalence is lower than that reported in previous studies. The study also revealed that camels with poor body condition were more susceptible to the disease and that anemia was significantly associated with trypanosomosis. During a participatory epidemiological investigation, it was found that all camel herders possessed good knowledge of surra. They were able to provide a clear description of the major clinical signs, transmission mechanisms, season of occurrence, and the effect of the disease on production. This knowledge enables them to detect the disease early, seek timely treatment, avoid risk factors, and adopt preventive measures. However, the major concerns raised by the herders were inadequate veterinary services and the lack of attention given to camels by the government. To reduce the disease prevalence and associated losses, enhancing veterinary services in the area is recommended. Support for good camel husbandry practices should also be provided, and identifying biting flies that act as surra vectors is crucial. Additionally, future studies should consider using more sensitive and specific techniques like serological and molecular assays, as this study relied on microscopy only.