Ticks and tick-borne disease control in a pastoral and an agro-pastoral farming systems in Kenya

J M Mugambi, F D Wesonga and S G Ndungu

Kenya Agricultural Research Institute (KARI), Muguga North, P.O.Box 32 Kikuyu Kenya
fwesonga@yahoo.com

Abstract

A study was undertaken on farmers’ perception of ticks as disease vectors and acaricide usage in a pastoral and an agro- pastoral farming systems in Kenya. The objective of the study was to identify, document and evaluate the various options for the management of ticks and tick-borne diseases in pastoral and agro pastoral farming systems. Ten (10) farms from each of the farming systems were selected from Kajiado and Loitokitok Districts. A semi- structured questionnaire was used to determine and gather information on ticks, tick-borne diseases and types of acaricides used, formulation, application techniques, frequency of application and perceived efficacy (of the acaricides). Information was also gathered on the use of ethno veterinary medicine in the two farming systems. Rhipicephalus appendiculatus, Rhipicephalus pulchellus, Boophilus decoloratus and Amblyomma variegatum were the commonest tick species in the two farming systems. The main tick-borne diseases prevalent in the two farming systems are East Coast fever, anaplasmosis, babesiosis and cowdriosis. Tick control using hand sprays and chemotherapy were the main method used to control tick-borne diseases in the two farming systems. The most commonly used group of acaricides was the Amitraz group with the majority of the farmers using this group of acaricides. Most of the farmers applied acaricides using hand sprays. Although most of the farmers indicated that they applied acaricides on their animals on a regular basis, very few of the farmers had information on correct formulation of the acaricides. A few of the farmers used a combination of amitrazes and synthetic pyrethroids (SPs). Overall, 10% the farmers indicated that the Amitraz groups of acaricides were not effective against most tick species prevalent in the two farming systems and hence they found it necessary to combine different groups of acaricides as a means of enhancing efficacy. 

Although most of the farmers could describe the symptoms of the main tick-borne diseases prevalent in the two farming systems, they could not accurately identify the tick vectors of the main diseases. It was concluded from the study that lack of adequate veterinary extension services was the main reason why the farmers could not correctly formulate and apply the acaricides at recommended frequency in the two farming systems. This was also the main reason for the perceived low efficacy of some of the acaricides by the farmers. An integrated approach for the control of tick-borne diseases is recommended for the two farming systems.

Key words: acaricides, anaplasmosis, babesiosis, East Coast fever, farming systems

Introduction

Tick transmitted and tick associated diseases together with those caused by internal parasites are one of the most important group of diseases limiting cattle productivity in Kenya (Ocaido et al 2008). Tick-borne diseases (TBDs) lead either to death of affected cattle, drastic reduction in milk production while recovered animals may suffer weight loss (Norval et al 1992; de Castro 1997; Swai et al 2009) reviewed the methods applied in the control of ticks and TBDs. Control of ticks and tick-borne diseases in Kenya is mainly through use of acaricides. The main method used to control TBDs in Kenya is application of acaricides to reduce vector challenge. The methods used for application of acaricides include plunge dipping, spray races, hand spraying or hand dressing. Several easier methods of acaricide application including use of impregnated ear-tags, neck-bands, tail bands and pour-ons have been developed (Young et al 1988). The principle objective in the acaricide tick control is to kill the infesting ticks in order to break the life cycle and therefore total coverage of all predilection sites of the various tick species is essential. In order to find out how the pastoralists cope with ticks and tick-borne diseases, two districts were selected for an in depth study of the control strategies that the pastoralists employ. Tick control costs are a burden especially to the resource poor farmers. A recent study undertaken on tick control costs in an agro- pastoral farming system indicated that the average annual cost of controlling ticks on an adult cow or bull is USD 4.154. This constitutes 73.8% and 85.6 % of the tick-borne disease control costs on ranches and agro pastoral farming systems, respectively (Ocaido et al 2008). Other novel methods of tick control have been developed but they have not found a wide application. The most common methods include pasture spelling, rotational burning of pastures using tick-repelling grasses (Mwase et al 1990), use of tick vaccines (Willadsen et al 1995) and restriction of livestock movement. Confinement of animals as in zero-grazing management systems also reduces the level of tick challenge (Gitau 1998, Wesonga 2012).      

The study was carried out in July 2010 in Kajiado Central District, where the vast majority of farmers are pastoralists and Loitoktok District, which is mainly inhabited by agro-pastoralists.  

Like in most other districts in the country, communal cattle dips are not functional following the withdrawal of government subsidy on ticks and TBD control under the structural adjustment program in the late 1980s. The problem of tick control in the two districts is compounded by the fact that there are hardly any veterinary extension services to guide the farmers on acaricide application (District Veterinary Officers, personal communication). The objective of the study was to identify, document and evaluate the various options for the management of ticks and tick-borne diseases in pastoral and agro pastoral farming systems It was expected that the information gathered during the study would greatly assist in the formulation of best-bet practices for the control of ticks and tick borne diseases in the two farming systems. 

Materials and methods 

Study site 

Kajiado Central District lies between latitude1⁰50´ 24”South of the Equator and longitude 36⁰ 47´23” East. Most of the land lies within the lower midland 6 (LM6) agro-ecological zone (AEZ) with bimodal rainfall, which is too little to support rain-fed agriculture.

Oloitoktok district is located within latitude 2^o55´30” South and longitude 37⁰ 30´36”East. It has several AEZs including LH2, LH3, UM3, 4 and 5 and LM5 and 6. Most of the land is within AEZ LM5 and LM6 where rainfall is little and of short duration making it unsuitable for rain-fed agriculture.  

Study population 

The study population consisted of pastoralists and agro-pastoralists farmers in Kajiado Central and Loitoktok respectively. Zebu cattle and the small East African goat are the predominant domestic animal species raised in the two districts. Based on the information obtained from the local veterinary department office, accurate livestock population figures were not available due to recent subdivision of the former Kajiado District into Kajiado Central and Loitokitok Districts (Table 1). 

Farmer selection  

Ten farmers were randomly selected from each of the two districts (Table 2). The local chiefs and assistant chiefs assisted in the selection of the farmers. Each of the selected farms was then visited and the study objectives were explained to the farmers. The protocol, objectives and aims of the study were also discussed with veterinary personnel in each of the two districts. Farm level data was collected using a standard questionnaire. The questionnaire was administered to the head of the household or the person normally in charge of livestock.

The questionnaire was administered in Kiswahili or translated into in the local Masaai where respondents had limited knowledge of Kiswahili. To maintain consistence, most of the questionnaires were designed in a closed format except for the introductory sections 1, 2 and 3 (Table 3). The questions were designed to identify the main acaricides used, acaricide dilution procedure (respondents were asked to describe the procedure), frequency of application, perceptions on acaricide efficacy and safety, role of women in livestock management and use of indigenous knowledge in tick control. 

Data collection 

Data was collected on the control of ticks and tick-borne diseases from interviews conducted with selected farmers, key informant interviews and farmer focus group meetings. Transect walks were conducted on a few of the selected farms to verify the accuracy of the information collected. 

Key informant interview 

Key informant interviews were conducted in the two districts on the occurrence of ticks and tick-borne diseases. A semi-structured questionnaire was administered to the respondents who included local veterinarians, livestock officers, provincial administration officers and selected farmers. A semi-structured interview was conducted to assess their perceptions on tick-borne diseases and tick control in the two districts. Retrospective data on reported cases of tick-borne diseases in each of the two districts was obtained from the district veterinary offices. Information on ticks and tick-borne diseases control was also obtained from the veterinary offices.  

Farmer focus discussions 

A farmer focus group discussion meeting was held in each of the two districts. In Kajiado Central district, the farmer focus group was attended by a total of 24 participants, 10 of whom were women. The participants were drawn from various professions, which included livestock keepers, provincial administration, teachers and politicians. The key issues discussed included ticks and tick-borne diseases, diagnosis and their control. The farmers were asked to describe the main tick species prevalent in the district and diseases that are associated with the tick species. 

The focus group meeting in Loitokitok District was attended by 14 participants, 2 of whom were women. Due to cultural inhibitions, some of the women invited for the focus group meeting declined to attend. The participants included livestock keepers, provincial administration staff and two retired teachers (one of whom was a woman). Generally, the level of education for the participants in the Loitokitak meeting was higher than that of the Kajiado participants. The main topics of discussion were the same as those discussed in the Kajiado focus group meeting.

Using the proportional piling technique, the farmers in each of the two districts were asked to rank the main tick–borne diseases prevalent in each of the study areas. The farmers were also asked to rank the main constraints to livestock production. 

Transect walks 

Transect walks were carried out on two randomly selected farms close to each of the four venues where the focus group meetings were held. The purpose of the walks was to make independent observations on farming enterprises, estimate the size of the farms, type of livestock kept, animal husbandry practices, tick species on the livestock and observe tick control procedures being carried out. 

Statistical analysis 

Descriptive statistics and chi square tests were used in the data analysis. The STATA, statistical package (StataCorp, 2007, version 10) was used in the analysis.  A value of p < 0.05 was used to denote significant difference between means. 

Results 

Key informant interview 

Goats are the main livestock species kept in Kajiado Central District, while cattle are the main species kept in Loitokitok District. From the information gathered from the key informants, the main tick-borne disease in Kajiado is East Coast fever (ECF). 3,276 cases were reported for the period 2007 to 2009 (Table 4). Anaplasmosis is the second most important disease in the district with 2,523 cases being reported within the three-year period. In Loitoktok District, anaplasmosis was the main tick-borne disease reported within the three-year period.  Most of the cattle dips, both private and public are not functional (Table 5). 

Farmer focus discussions 

In Kajiado Central District, the participants ranked ECF, heartwater, alopecia and foot rot as the main livestock diseases in the district while lack of adequate finances, water shortage, labour and poor veterinary infrastructure were ranked as the main constraints to the livestock production (Tables 6 and 7). It was found that there was widespread misuse of acaricides, as the government no longer controlled the type of acaricide used. For instance, there is widespread use of pyrethroids, yet the Amitraz group ought to be the “first line” acaricides in most parts of the country except in regions where tsetse flies are a menace. 

In Loitokitok District, the participants ranked anaplasma, ECF, pneumonia and heartwater as the main livestock diseases while lack of extension services particularly with regard to the use of acaricides, poor veterinary infrastructure, water and lack of finance was ranked as the main constraints to livestock production (Tables 6 and 7). In the absence of extension services, the farmers in the district rely on agrovet attendants who provide information which farmers often found confusing. This was due to what farmers attributed to unqualified agrovet attendants hired by the owners of the agrovets to manage the agrovet shops. There is a big shortage of veterinarians in the district. There is only one government vet (who is also the District Veterinary Officer) and one private vet who specializes in artificial insemination services. 

In both districts, the farmers could not correctly link the tick-borne diseases with the tick vectors (Table 8). Amblyomma variegatum was incorrectly linked with the transmission of ECF while Rhipicephalus evertsi was linked with the transmission of Erhlichia ruminantium and foot rot. 

Farmer interviews 

Acaricides were mainly applied by the head of the household who in most cases was male (except where the house hold was employed away from home or was dead and in which case the wife was the defacto house hold head). A total of 20 farmers were visited to assess; type of acaricide used, formulation of acaricide, method of application, frequency of application, and age at which acaricide is first applied on livestock and perception on efficacy of the acaricides that are commonly used in the two farming systems.  The results are summarised in Table 9.  

Most of the farmers in the two districts rely on hand sprays for the control of ticks on their farms as there are very few functional cattle dips in the two districts.

The main source of acaricides are the local Agrovets (Table 9). Most of the farmers indicated that they practiced tick control on a regular basis (once a week to once every two weeks). In both districts, all interviewed farmers indicated that tick infestation of livestock and tick-borne diseases increased soon after the end of the rainy seasons. In both districts, the rains are normally concentrated in two short seasons: end of March to May, and end of October to December. 

Tick control generally commenced at the age of two weeks for cattle, sheep and goats.

A significantly (P < 0.05) higher number of farmers used the Amitraz group of acaricides. The most commonly used acaricide in the two production systems is Triatix. Effectiveness of the acaricide was the main criteria for selection (80% of the respondents). A significantly (P < 0.05) higher number of farmers were satisfied with the efficacy of the acaricide products that they were using at the time of the visit. 

However, 30% and 50% of the farmers respectively in the agro-pastoral and the pastoral agricultural systems concurrently used the synthetic pyrethroids (SP) with the Amitraz products to control ticks on their farms. This, the farmers explained was to enhance the potency of the Amitraz products in instances where the farmers felt that Amistraz products were not effective enough.  

Most the farmers were unable to dilute the acaricides to the right concentration. Only 30% and 10 % of the farmers interviewed in the agro-pastoral and the pastoral agricultural systems respectively used the right concentration of the products. The level of awareness on products available and how they applied to control ticks was higher in the agro-pastoral compared to the pastoral production community. Most of the farmers were of the view that the products they applied on their animals to control ticks were efficacious enough. Only a few of the farmers had concerns about the safety of the products used. 

Although men played the leading role in tick control on the farms, women also play an active role in the control of ticks especially if their husbands are away or tied down by other engagements. 

The farmers in both livestock production systems indicated they were not aware of natural products that can used to control ticks. However up to 20 % of the farmers used products like diazinon, paraffin or used engine oil to control ticks as alternatives to acaricides.    

Apart from tick control, the farmers indicated that the other method used to control TBDs was the use of chemotherapeutic drugs such as long acting tetracylines and bupavarquone (Butalex®).

Transect walks 

It was established during the transect walks that Rhipicephalus appendiculatus, Rhipicephalus pulchellus, Boophilus decoloratus and Amblyomma variegatum were the commonest tick species in the two farming systems. It was also observed that application of the acaricides was undertaken by aerial spraying whereby at least 20 animals were herded into an enclosure and about 20 litres of the dip-wash was sprayed onto them. Tick samples collected from the animals were taken to the VRC laboratories at Muguga for identification up to species level according to Kaiser et al (1988). 

Discussion 

There was high enthusiasm by the farmers towards the survey in the two districts. This was evident from the fact that none of the selected farmers declined to take part in survey. This was explained by the fact that farmers in the two districts hardly get any veterinary services from either the government or private veterinary practitioners. Therefore, this provided the opportunity for the farmers to present animal health problems they have to contend with in an environment of poor veterinary infrastructure. 

The use of qualitative means (questionnaires and ranking) to identify disease constraints to livestock production was useful in providing an insight into the most important diseases in the two districts from the farmers’ perceptive (Wesonga et al 2012). The farmers were able to accurately identify the main diseases prevalent in the two districts. The information gathered on TBDs and tick control from the individual farmer interviews and farmer focus group meetings was similar to that obtained from the key informant interviews.  

The pastoral communities in the two districts where the study was conducted are conversant with the main tick-borne diseases, but do not seem to be conversant with the vector ticks of the TBDs. Besides, only a few farmers selected for the survey were able to correctly formulate the acaricides and apply at the right frequency. The fact that the farmers could not accurately link the TBDS with their tick vectors implies that the farmers are not conversant with the predilection sites of the tick vectors. As a result, the farmers are content with spraying main body or trunk of livestock, leaving out the target predilection sites such the ear and under the belly where Rhipicephalus appendiculatuts and Amblyomma variegatum are respectively found. This was demonstrated by the mode of application of the acaricides, which involved herding of the animals into an enclosure and spraying the acaricide on top (of the animals). Besides this being a waste of acaricides, the spraying of the animals is an exercise in futility as it leaves the animals exposed to the key TBDs.

 The practice of combining amitrazes and synthetic pyrethroids is a major cause of concern, as it is likely to reduce the effective life of the two acaricides through rapid development of resistance to the two compounds. 

Veterinary extension services are necessary to assist farmers on the right choice of acaricides to be used as well as to how effectively apply the hand spray technique of tick control, as it is not as reliable as dips. Farmers need to be trained on how to prepare the correct dilution of the acaricides and the predilection sites of the ticks where the spraying should be focused on the body of animals. Currently, there are inadequate veterinary extension services in the two districts to provide the farmers with the required technical information on tick control.  

Although, it is recognized that AHA or Para veterinary staff have an important role to play in the provision of veterinary services in the country, their scope of training requires intervention of services of qualified veterinarians on certain technical and policy issues. 

Studies by Umali et al (1994), Otieno- Oruko (2000) and Mugunieri et al (2004) do indicate that Para veterinary staff and Community Based Animal Health Workers (CBAHW) can play a significant role in animal health delivery if appropriate policies are put in place to strengthen their activities. The studies found that Para veterinary staff and CABHW who were provided with basic training in animal health and entrepreneurial skills were successful in delivering animal health services particularly in marginal areas.

Based on the findings of this study, it is recommended that services of CABHW be used to complement the inadequate veterinary services, particularly the extension services, provided by the Department of Veterinary Services.   

It was observed during the survey that, tick control on calves, lambs and kids commenced as early as two weeks of age (Perry and Young 1995; Gitau 1998; Kivaria et al 2004). This practice is likely to lead to a state of endemic instability if young animals are not allowed to be exposed to the TBDs early in life. There should also be a policy formulated by the relevant line ministry on frequent farmer trainings on acaricide in pastoral farming systems in country. 

The key lesson learnt from the study was that the private sector, especially the agrovets have an important role to play with regard to the control of ticks and tick-borne diseases in pastoral and agro pastoral farming systems. If properly regulated, agrovets can be used as the entry point with regard to the dissemination of information on proper usage of acaricides. In collaboration with the line ministries, they can also be used as key sources of information on new technologies on the control of tick-borne diseases in pastoral farming systems where farmers may have limited access to electronic media. 

Based on the findings of the study, it is recommended that an integrated approach to the control of ticks and tick-borne diseases be adopted in the pastoral and agro pastoral farming systems in Kenya. In view of limited access to extension services in these farming systems, especially with regard to correct acaricide usage, immunization against ECF together with strategic tick control would be the ideal approach. Future studies in the agro pastoral and pastoral farming systems should focus on tick dynamics in order to establish appropriate tick control frequency regimes in these areas. Environmental and farm factors are known to greatly influence the incidence of tick-borne diseases (Gachohi et al 2011). 

Acknowledgements 

The authors would like to thank ASARECA for funding the study. The authors would also like to thank the DVOs and the staff of the two districts for their assistance. The support of the farmers who participated is highly appreciated.  

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Received 2 February 2012; Accepted 2 April 2012; Published 7 May 2012

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