Seroprevalence and potential risk factors of Leptospira interrogans serovar Hardjo infection in dairy cattle of Tanahun district, Nepal

Introduction

The agriculture sector contributes approximately 24% of gross domestic product (GDP) to the national economy of Nepal (AITC 2023), with the livestock sector contributing approximately a quarter of this (Department of Livestock Services 2022). Most Nepalese agriculture households rear at least one type of livestock such as cattle, buffalo, goat, sheep, pigs and poultry. Cattle rearing is a common practice in Nepal, with a total of 7.41 million head in the national herd (Ministry of Agriculture and Livestock Development 2022). Nepalese livestock farming is facing several challenges that include low production and productivity and a high burden of diseases, many of which are zoonotic.

Leptospirosis is one of the zoonotic diseases that are occasionally detected in Nepal in both animal and human populations (Shrestha et al. 2018). It is a globally recognised, yet a neglected, bacterial zoonotic disease (Bharti et al. 2003; Adler and de la Peña Moctezuma 2010). The global burden of leptospirosis is unknown but it is estimated that there are more than 500,000 human cases annually, with a fatality rate of up to 25% in some regions (Zakharova et al. 2021). Among the livestock population, species commonly affected by leptospirosis include cattle, buffalo, goat, sheep, horse and pig, resulting in huge economic losses to the farming communities because of the reproductive problems caused by the disease that include infertility, abortion, stillbirths, weak calves and decreased milk yield (Srivastava 2008; Hensley 2016; Fávero et al. 2017). This disease is caused by an aerobic, Gram-negative, actively motile spirochete of the genus Leptospira spp. The Leptospira interrogans serovar Hardjo is commonly isolated in cattle (Bolin 2000; Leonard et al. 2004; Guerra 2013). Disease transmission, in both humans and animals, can occur through direct contact with urine, tissue or body fluids of carrier animals and indirectly via contaminated soil or water. Human to human transmission has also been recorded through breast-feeding (Bolin and Koellner 1988).

Variable prevalence of Leptospira infection among domestic animals has been reported. Srivastava (2008) showed varying seroprevalence of Leptospira exposure in different species (5.4% in buffaloes, 7.5% in cattle, 12.5% in sheep, 14.6% in horses and 15.9% in dogs) in various states of India. Likewise, a seroprevalence of 40.5%, 31% and 16% in cattle, buffalo and pig respectively, has been reported in West Malaysia (Bahaman et al. 1987). The prevalence of leptospiral serotypes varies with Balamurugan et al. (2013) in Odisha, India, reporting the seroprevalence of L. interrogans serovar Hardjo antibodies to be 23.5%, whereas that for L. australis was as high as 50.9%, with others being lower in abundance. Similarly, in Gujarat, India, L. interrogans serovar Hardjo and L. pomona seroprevalence was found to be 15.56% and 28.89% respectively, in 398 sera screened from cattle (Patel et al. 2014).

Cattle are the major livestock reared in South-east Asian countries including Nepal, with L. interrogans serovar Hardjo being the predominant serovar in cattle. It poses a threat to cattle health in the region, as well as a significant risk to human health in rural and farming communities. Moreover, differences in prevalence among and within countries in the region, owing to variations in geography, climatic conditions, and management practices, together with the resistance exhibited by various breeds, are likely to occur (Hoffmann 2010). The prevalence of this disease is likely to be underestimated in both human and animal populations because of the lack of reliable diagnostic methods, under-reporting and inefficient surveillance facilities across countries in the region (Victoriano et al. 2009; Hartskeerl et al. 2011). The burden of leptospirosis is poorly understood in Nepal because of limited research being conducted, although this disease has been listed in the Nepal Gazette as a top 10 prioritised zoonotic disease in Nepal.

The aim of this study was to gain a greater understanding of the epidemiology of Leptospira infections in Nepal by focusing on serovar Hardjo prevalence in dairy cattle. Tanahun is an emerging district for commercial dairy farming in Nepal. However, only limited studies have been conducted to understand the burden of animal disease, including the zoonotic diseases in this district. To the best of our knowledge, no study has been conducted yet in Tanahun to understand the burden of Leptospira spp. in the cattle population. The objective of this research was to determine seroprevalence of Leptospira exposure in the cattle population of Tanahun, identify the associated risk factors in the herd and in individual animals and to know farmers awareness and level of understanding on zoonoses. The insights provided by this research should help guide disease control strategies for leptospirosis in Nepal.

Materials and methods

Sampling technique

Samples were collected from each of the 10 municipalities located in Tanahun district by using a three-stage random sampling procedure (Fig. 1). The distribution of the cattle population present in each of the municipalities was assessed before finalizing the sampling regimen. At first, 42 villages or wards were selected randomly within the Tanahun district and then 216 farms or herds from the selected areas were randomly chosen for the study on the basis of the farmers willingness to participate and availability. Herd size was found to be ranging from 1 to 140 animals. On chosen farms, cattle were selected randomly and, on average, most farms had three cattle sampled.

Fig. 1.

Map of Nepal, showing site of sample collection inside Tanahun district.

Results

Seroprevalence study

Herd-level and animal-level seroprevalence

Of the 216 herds tested, 6.48%, (95% CI: 3.59–10.64) tested positive for Leptospira exposure. The herd size ranged from 1 to 140 cattle, with three being the median value. Likewise, the study demonstrated that out of the total samples examined, only 4.91% (n = 20/407, 95%CI: 3.20–7.47) were positive for L. interrogans serovar Hardjo specific antibodies whereas, 4.18% (n = 17/407, 95%CI: 2.62–6.59) were classified as suspected samples.

Multivariable logistic regression analysis for herd-level and animal-level risk factors

From univariate regression, only 13/25 herd and 8/13 individual animal explanatory variables, meeting the cut off criteria of P ≤ 0.3, were selected to run in the final multivariable logistic models as shown in Tables 2 and 3. Multivariable logistic regression analysis was performed independently for these selected herd and individual animal explanatory variables.

Table 2.Animal-level risk factors associated with leptospirosis infection in cattle of Tanahun by multivariable logistic regression analysis.

Variable	Level	Total number (N = 390)	Number of seropositive (n)	Adjusted OR	95% CI	P-value
Breed	Holstein cross	136	5	1.467	0.595–3.620	0.406
	Jersey cross	184	7	4.06	0.20–27.51	0.216
	Local Pahadi and stray cattle	70	8	Ref
Bull	Yes	85	10	0.619	0.120–3.191	0.567
	No	305	10	Ref
Cattle origin	Purchased	134	7	2.756	1.191–6.381	0.018*
	Stray/gifts	26	7	2.043	0.664–6.482	0.208
	Home bred	230	6	Ref
Lactation status	Lactating	203	6	1.516	0.816–2.815	0.188
	Non-lactating	187	14	Ref
Milk yield pattern	Reduced	132	6	0.621	0.246–1.569	0.314
	Normal	258	14	Ref
Pregnancy status	Pregnant	131	6	0.765	0.421–1.393	0.381
	Non-pregnant	259	14	Ref
Reproductive problems	Yes	86	7	1.599	0.464–5.510	0.457
	No	304	13	Ref
Tick infestation	Yes	158	15	0.301	0.099–0.919	0.035*
	No	232	5	Ref

CI, confidence interval; OR, odds ratio; *P < 0.05, a significant variable; N, total number of sample taken; n, total number of seropositive cattle; Ref, reference category/level.

Table 3.Herd-level risk factors associated with leptospirosis infection in the cattle of Tanahun by multivariable logistic regression analysis.

Variable	Level	Total number (N = 216)	Number of sero-positive (n)	Adjusted OR	95% CI	P-value
Herd size (median = 3)	>3	106	9	8.516	1.210–59.893	0.031*
	<=3	110	5	Ref
Multispecies farming	Yes	156	12	0.105	0.010–1.057	0.056
	No	60	2	Ref
Frequency of vehicle movements	Frequently	80	6	0.861	0.380–1.951	0.720
	Less frequently	136	8	Ref
Housing type	Intensive	65	2	5.025	0.788–32.062	0.088
	Semi-intensive	133	9	3.291	0.842–16.025	0.128
	Extensive	18	3	Ref
Bedding type	Mat	23	1	2.321	0.200–27.530	0.504
	Cemented	146	7	1.813	0.089–16.174	0.625
	Earthen	47	6	Ref
Isolation of sick animals	Yes	94	4	1.050	0.156–7.030	0.962
	No	122	10	Ref
Rodents	Yes	209	12	26.922	1.220–593.867	0.037*
	No	7	2	Ref
Breeding method	Both	11	0	1.851	0.434–7.901	0.410
	Artificial insemination	149	6	1.704	0.091–10.257	0.651
	Bull mating	14	4	0.921	0.164–5.291	0.935
	Not any	42	4	Ref
Feed contamination with soil	Yes	153	11	0.490	0.160–1.47	0.201
	No	63	3	Ref
Working nature of farmers	Both	178	9	3.657	1.152–11.605	0.028*
	In cow shed or field only	38	5	Ref
Disposal pits	Yes	170	9	0.228	0.025–2.059	0.188
	No	46	5
Animal Import	Yes	117	11	0.240	0.035–1.600	0.139
	No	99	3	Ref
Buy/sell	Within a district	152	11	0.140	0.019–0.970	0.046*
	Out of district	64	3	Ref

CI, confidence intervals; OR, odd ratios; *P < 0.05, a significant variable; N, total number of sample taken; n, total number of seropositive cattle; Ref, reference category/level.

In the final animal-level multivariable regression, only two animal-level risk factors, cattle origin and tick infestation, were significantly associated with seropositivity to Leptospira organism (Table 2). Purchased cattle herds had a significant 2.75-fold increase in the odds of being exposed to L. interrogans serovar Hardjo (P = 0.018, OR: 2.756, 95% CI: 1.191–6.381) relative to stray and home-bred cattle. Herds with tick infestations had a 0.3-fold decrease in the odds of being seropositive (P = 0.035, OR: 0.301, 95% CI: 0.10–0.92), as shown in Fig. 2.

Fig. 2.

Leptospira exposure in total sampled cattle population. (a) Cattle-origin, P ≤ 0.05. (b) Tick-infestations, P ≤ 0.05.

In the final herd-level multivariable model, the four herd-level risk factors, i.e. buying and selling of animals within and out of district, working nature of farmers, presence or absence of rodents, and herd size, were significantly associated with seropositivity to Leptospira organism (Table 3).

Considering sex-wise prevalence, it was evident that females tended to be less affected 4.75% (16/337) than were males 7.55% (4/53), although this was not significant (P ≥ 0.05). The median age of the cattle in the herd was 5 years, ranging from 2.5 months to 23 years. So, age is categorized as ‘≤5’ or ‘>5’. The prevalence tended to be higher (P ≥ 0.05) with the younger age group, with 5.29% (12/227) being affected relative to the older group (4.91%; 8/163).

With respect to herd size, herds with more than three cattle were found to be significantly more affected 8.49% (9/106) than were herds with three or fewer cattle 4.54% (5/110). Herds with more than three cattle were 8.5 times more likely to be seropositive to Leptospira organism (P = 0.031, OR: 8.516, 95% CI: 1.210–59.893) than were those with three or fewer cattle (Fig. 3).

Fig. 3.

Leptospira exposure in total sampled cattle population (a) Herd size, P ≤ 0.05; (b) Presence or absence of Rodents P ≤ 0.05.

Similarly, infestations of rodents were apparent in the majority (96.76%; 209/216) of herds. Farms where rodents were found had a 26.9-fold increase in the odds of being exposed to L. interrogans serovar Hardjo (P = 0.037, OR: 26.922, 95% CI: 1.220–593.867) than those farms with fewer or no rodents (Fig. 3).

The cattle herds bought and sold within the district were less likely to be affected by leptospirosis (P = 0.046, OR: 0.135, 95% CI: 0.019–0.965) than were those moved among districts or across borders.

In 82.41% (178/216) of the farms, owners themselves performed both the cow shed and field activities. It was found that the cattle herds reared by the farmers working in both the cow shed and field had a significantly increased risk, 3.65 times greater, of developing leptospirosis seropositivity (P = 0.028, OR: 3.657, 95% CI: 1.152–11.605) than those herds reared by farmers working only in the cow sheds (Fig. 4).

Fig. 4.

Leptospira exposure in total sampled cattle population. (a) Buying and selling of animals, P ≤ 0.05. (b) Working nature of farmers, P ≤ 0.05.

When comparing breeds, local Pahadi and stray cattle tended to be more affected (11.43%; 8/70) than were Jersey cross (3.80%; 7/184) and Holstein cross (3.68%; 5/136) animals. Although the result was insignificant in multivariate analysis, it was significant in univariate analysis.

Awareness on zoonotic diseases

More than half of the respondents (58.33%; 126/216) were aware of zoonoses. Approximately, 55.56% (120/216) of the respondents knew that disease can be transmitted through contaminated milk, uncooked or raw meat, blood, contaminated soil, contaminated water, body discharges and genital secretions. Of 216 farmers surveyed, 15.28% (33/216) had heard of leptospirosis as an animal disease, whereas only 5.56% (12/216) of the farmers knew that leptospirosis was zoonotic.

Discussion

The present study assessed the serological evidence of L. interrogans serovar Hardjo infections in Tanahun district and identified potential risk variables at the animal and herd levels. The findings showed that the seroprevalence of L. interrogans serovar Hardjo among dairy cattle herds of the Tanahun district of Nepal is very similar to that reported by Khanal et al. (2018). In their study, 6% (10/160) and 4.51% (7/155) of dairy cattle were seropositive to Leptospira interrogans serovar Hardjo infection in the pre-monsoon and the post-monsoon seasons respectively. Another study by Rawal and Shrestha (2019) showed that dairy cattle in the Bhaktapur district of Nepal had a sero-detection rate of 5.11% (9/176), which is consistent with our findings. Similarly, a study conducted by Vongxay et al. (2012) in Lao PDR found 6% antibodies against L. interrogans serovar Hardjo in serum samples of cattle assessed by ELISA. The similarity in Leptospira interrogans serovar Hardjo seroprevalence between our study in Tanahun district and other districts within Nepal can largely be attributed to consistent climatic conditions, and livestock rearing practices in terms of animal husbandry, grazing, and sheltering. These practices contribute to comparable levels of exposure to environmental sources of Leptospira, such as contaminated water and soil, resulting in similar seroprevalence findings. Additionally, the availability and use of ELISA, having similar sensitivity and specificity, as a major serological diagnostic test minimizes variations in the detection and reporting of seroprevalence rates of L. interrogans serovar Hardjo.

However, Joshi and Shrestha (2011) detected a higher seroprevalence of Leptospira exposure in dairy cows (11.0%; 12/114) reared in mid-hills regions of Nepal. Mandal et al. (2008) reported 16.84%, and Savalia and Mahendra (2008) reported 14.77% seroprevalence of Leptospira exposure in dairy cattle of West Bengal and Gujarat state of India respectively, both of which compare well with our present findings. In contrast, higher seroprevalence at the rate of 42.5% (Balamurugan et al. 2013) was recorded in dairy cattle from Orissa and 22% from Uttaranchal, Tamil Nadu, Uttar Pradesh of India (Mariya et al. 2007). Similarly, a study conducted in Lao PDR by Olmo et al. (2019) detected 12.8% antibodies against L. interrogans serovar Hardjo in serum samples of cattle. Moreover, a study by Gamage et al. (2011) reported 20.3% of bovine leptospirosis in Sri Lanka. Prevalence of bovine leptospirosis in dairy herds was reported as 31.3% and 47.3% in research conducted by Tabatabaeizadeh et al. (2011) and Parvez and Faruque (2015) from Iran and Bangladesh respectively. In contrast to our findings, higher seroprevalence observed in studies conducted in neighbouring countries such as India, Bangladesh, Sri Lanka, and in other regions, may reflect the endemic nature of diseases, differences in test methods, livestock rearing practices, and environmental conditions. Because the microscopic agglutination test (MAT) is a serovar-serogroup specific test, having better sensitivity and specificity, it is the preferred choice for sero-epidemiologic studies (WHO 2007). Use of gold standard serological tests, such as MAT that is highly sensitive to detect specific Leptospira antibodies, including L. interrogans serovar Hardjo over ELISA, thus results in higher seroprevalence. Variations in climatic conditions, especially rainfall and humidity, could facilitate the survival and spread of Leptospira in the environment, contributing to higher seroprevalence in those areas. Also, difference in livestock rearing practices among regions can significantly affect exposure rates.

Nevertheless, because of variations in epidemiological study design, study objectives, sample size and geography, leptospirosis prevalence may vary over time. Therefore, even though our findings align closely with other districts within Nepal, the differences observed with respect to other countries underscore the importance of local context in understanding disease prevalence.

In our study, the higher seroprevalence of leptospirosis in purchased and stray cattle herds than in home-bred cattle are symptomatic of transmission between herds. Because Tanahun district connects with the Kaski, Gorkha, Lamjung and Chitwan districts, the frequency of movements of human, vehicles and animal herds is high year-round. Thus, the increased frequency of contact between herds significantly elevates the risk of exposure to Leptospira interrogans serovar Hardjo, because it enhances the opportunities for the organism to spread through direct contact or via contaminating shared water sources, soil, or feed (Hashimoto et al. 2012). Purchased cattle, especially those from different regions or with unknown health histories, may carry and shed the Leptospira without showing symptoms, serving as a hidden reservoir that perpetuates the cycle of Leptospira transmission within and among herds. Within herd settings, close proximity of animals facilitates the transmission of Leptospira through urine, which is the primary mode of shedding for this pathogen. Similarly, free-roaming stray cattle, often of unknown health status, are likely to expose healthy herds to Leptospira infection, especially in environments where they intermingle with domesticated cattle. The increased contact and subsequent exposure not only amplify the risk for the cattle but also pose a greater risk of zoonotic transmission to humans, particularly those working closely with livestock (Balamurugan et al. 2013). Thus, herd management is crucial during transportation of cattle and other susceptible animals to control the spread of the Leptospira organism. Herd management should include implementing quarantine measures for newly purchased cattle before allowing them to join the main herd, and regular health screenings should be standard practice. For stray cattle, relocating them to designated shelters where they can be monitored and treated, along with preventing their access to common grazing areas and water sources, are interventions that further reduce the risk of Leptospira transmission to healthy herds.

Seropositivity to L. interrogans serovar Hardjo was lower in Bandipur, Devghat rural municipality, followed by Bhanu and Vyas municipalities, and higher in Suklagandaki, followed by Myagdey, Vimad and Ghiring municipalities. Lower seroprevalence in these municipalities might be due to closer management of dairy herds where culling of unproductive and unhealthy animals is closely monitored, whereas farm sanitation and knowledge of the disease transmission cycle among farmers helped lower Leptospira exposure in cattle herds. Knowledge of the transmission cycle empowers farmers to implement targeted interventions such as quarantine measures, isolation of suspected animal, routine physical examination, and farm sanitation (Ryan et al. 2012). As such, timely culling helps remove potential carriers from the herd, decreasing the chance of transmission. Farm sanitation, including proper management of waste and water sources, reduces environmental contamination by Leptospira organisms (Sharma et al. 2003; Zakharova et al. 2021). These practices, when implemented effectively, can significantly reduce the risk of Leptospira transmission in cattle populations.

In contrast to this, samples collected from Suklagandaki included more stray and physically unhealthy cattle, which increases the risk of exposure to Leptospira infection. Whereas samples from Vimad municipality were from cattle herds with a history of reproductive problems, including repeat breeding, abortion, metritis and retention of placenta, which indicates an increased exposure to Leptospira infection. Also, in the Myagdey municipality, most of the cattle farms from where samples were taken were located near to the highway. However, lower frequency of animal movement and relatively small number of samples taken from Aabukhaireni and Rising rural municipalities might explain the lower seroprevalence rates. Studies have shown that farms with inadequate biosecurity measures, including uncontrolled animal movement, introduce new sources of infection and spread the pathogen within and among herds, thus increasing the exposure risk (Balamurugan et al. 2013; Picardeau 2013). Additionally, ensuring an adequate sample size in seroprevalence studies is crucial to accurately assess the risk factors and prevalence, because smaller samples may not capture the full extent of population exposure (Skinner 2016).

In relation to herd size, several studies have demonstrated that a larger herd size provides a higher risk for Leptospira exposure (Ryan et al. 2012; Miyama et al. 2018). This is consistent with our results. Larger herd size increases the likelihood of Leptospira transmission because of closer contact among animals, which facilitates the spread of the organism through urine, a primary mode of transmission. Additionally, larger herds often share water and grazing resources, creating more opportunities for environmental contamination and subsequent exposure. Although smaller herds may reduce the risk of Leptospira transmission because of lower animal density and contact, this might not be economically feasible for all types of farmers. Because vaccination against leptospirosis has not been introduced in Nepal, it is recommended that farmers, especially with a larger herd size, implement preventive measures such as improved biosecurity practices to mitigate the risk of Leptospira infection.

Our study showed that rodents were frequently present in herds and could be an important risk factor as rodents play a vital role as a carrier for leptospirosis (Adler and de la Peña Moctezuma 2010). In Tanahun, the timing of our study from August to December included the months of October to November when rice paddy harvesting was conducted and rodents were sighted more frequently. Rats had unrestricted access to paddy hay, the principal dietary component of dairy cattle. Interestingly, study conducted by Olmo et al. (2019) in farms of Lao PDR showed a 9.3% prevalence of rodents and this was not considered to be the major risk factor for leptospirosis infection in cattle. Leptospirosis outbreaks typically correspond to the rainy and paddy harvesting season, with a rise in cases from August and a decrease in cases in November (Zavitsanou and Babatsikou 2008; Victoriano et al. 2009). Poverty and poor education were implicated as conditions leading to rodent-borne transmissions (LaRocque et al. 2005). Rodents should be controlled on the farm because they act as carriers of zoonotic pathogens such as Leptospira and can transmit diseases between animals thus, increasing the risk of outbreaks. However, the risk of leptospirosis transmission can be successfully reduced through the use of rodenticides, animal trapping, and improved sanitation (Mohan Rao 2006).

Furthermore, our findings showed a significant relationship between the nature of farm work and seropositivity to the Leptospira organism (Table 3). Farmers who work both in farms and fields are at a higher risk of contracting leptospirosis because of an increased exposure to environments contaminated with Leptospira organism. Working in fields, especially during the rainy season, can expose farmers to contaminated water and soil, whereas farm work increases direct contact with potentially infected livestock. This dual exposure raises the likelihood of infection. This finding is consistent with previous reports from south-western Iran (Alavi et al. 2013) and Malaysia (Sejvar et al. 2003). To reduce the risk of Leptospira exposure, farmers should practice good hygiene, such as wearing protective clothing and boots, and washing hands and feet after working in potentially contaminated areas. Additionally, implementing measures such as regular health checks of cattle and proper waste management on farms could further reduce the chances of transmission.

Our study also showed that the practice of buying and selling animals within and outside the local district, especially from live animal markets, have a significant effect on increasing the risk of Leptospira infection. The movement of animals through buying and selling, especially across districts, might introduce new sources of Leptospira organisms into existing herds that may have previously been unexposed, thus increasing the overall risk of the disease. Therefore, strict biosecurity measures should be followed when buying or selling animals, including quarantine periods and health screenings, to prevent the introduction of infected animals into healthy herds. In present study, seroprevalence of L. interrogans serovar Hardjo in cattle was found to be insignificant with respect to their age, sex and breed.

The survey taken in the present study was conducted within a population where approximately 30% were literate, with only approximately 8% having advanced to a higher level of education. Our findings reflect this level of education and assist with understanding the level of awareness on zoonosis in the study population. Various studies have shown that the adoption of intensive awareness campaigns, in combination with vaccination of cattle, is successful in reducing the incidence of leptospirosis (Crump et al. 2001; Thornley et al. 2002; Leptospirosis in Japan 2008). Although implementing awareness campaigns and vaccination program for controlling leptospirosis in Nepal is feasible, it may face challenges because of limited government resources and competing public health priorities. Furthermore, studies similar to the current study should be replicated in other parts of Nepal to determine the overall prevalence of leptospirosis in the animal population, so that targeted awareness and vaccination programs in high-risk areas can be implemented. This is particularly important in areas with significant livestock activity, to prevent disease outbreaks and protect vulnerable populations.

Conclusions and recommendations

Herd and animal levels of seroprevalence of Leptospira exposure were found to be 6.48% (14/216) and 4.91% (20/407) respectively, among the dairy cattle herds in the Tanahun district of Nepal. In the final multivariable model, four potential herd-level risk factors, i.e. buying and selling of animals within and out of district, the nature of farm work performed by farmers, presence of rodents and a herd size greater than three animals were significantly associated with seropositivity to Leptospira organism. Similarly, two animal-level risk factors, i.e. cattle origin and tick infestations, were significant factors with respect to Leptospira exposure. Interestingly, 58.33% (126/216) of the respondents were aware of the concept of zoonosis, but only 5.56% (12/216) of the farmers knew leptospirosis as a zoonotic disease.

Based on these research findings, the farmers and general public, especially in high-risk areas, of Tanahun should be made aware of this zoonosis. The key precautionary measures should be consistently applied to rule out associated risk factors of leptospirosis, including regular maintenance of farm hygiene, use of protective clothing, such as boots and gloves while handling animals or working in fields, especially during the rainy season, and ensuring supply of safe and clean water sources for both animals and humans. Moreover, these findings would be helpful in developing targeted control and contingency plans for the management of this disease. By identifying the seroprevalence and risk factors, the study has provided a foundation for implementing effective interventions, such as improved biosecurity measures. For future studies, it is recommended to conduct longitudinal research to track infection trends over time, explore the genetic diversity of Leptospira strains circulating in livestock, and assess the impact of environmental factors on disease transmission. Investigating the link between seroprevalence and clinical disease in both animals and humans would also provide valuable insights for comprehensive leptospirosis management strategies.

Testing for markers for the molecular characterization of pathogenic isolates, including the introduction of a microscopic agglutination test, needs to be performed to identify different serovars of Leptospira spp., along with L. interrogans serovar Hardjo, to obtain a more detailed picture of their comparative prevalence nationwide. A national action plan for the control of prioritized zoonotic diseases such as leptospirosis should be designed and implemented. This needs to include effective cooperation across the public health sectors in developing an effective one health approach to disease control.